ATMEL AT32UC3A3256S-CTUR 32-bit avrâ®microcontroller Datasheet

Features
• High Performance, Low Power 32-bit AVR® Microcontroller
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– Compact Single-Cycle RISC Instruction Set Including DSP Instruction Set
– Read-Modify-Write Instructions and Atomic Bit Manipulation
– Performing up to 1.51DMIPS/MHz
• Up to 92DMIPS Running at 66MHz from Flash (1 Wait-State)
• Up to 54 DMIPS Running at 36MHz from Flash (0 Wait-State)
– Memory Protection Unit
Multi-Layer Bus System
– High-Performance Data Transfers on Separate Buses for Increased Performance
– 8 Peripheral DMA Channels (PDCA) Improves Speed for Peripheral
Communication
– 4 generic DMA Channels for High Bandwidth Data Paths
Internal High-Speed Flash
– 256KBytes, 128KBytes, 64KBytes versions
– Single-Cycle Flash Access up to 36MHz
– Prefetch Buffer Optimizing Instruction Execution at Maximum Speed
– 4 ms Page Programming Time and 8ms Full-Chip Erase Time
– 100,000 Write Cycles, 15-year Data Retention Capability
– Flash Security Locks and User Defined Configuration Area
Internal High-Speed SRAM
– 64KBytes Single-Cycle Access at Full Speed, Connected to CPU Local Bus
– 64KBytes (2x32KBytes with independent access) on the Multi-Layer Bus System
Interrupt Controller
– Autovectored Low Latency Interrupt Service with Programmable Priority
System Functions
– Power and Clock Manager Including Internal RC Clock and One 32KHz Oscillator
– Two Multipurpose Oscillators and Two Phase-Lock-Loop (PLL),
– Watchdog Timer, Real-Time Clock Timer
External Memories
– Support SDRAM, SRAM, NandFlash (1-bit and 4-bit ECC), Compact Flash
– Up to 66 MHz
External Storage device support
– MultiMediaCard (MMC V4.3), Secure-Digital (SD V2.0), SDIO V1.1
– CE-ATA V1.1, FastSD, SmartMedia, Compact Flash
– Memory Stick: Standard Format V1.40, PRO Format V1.00, Micro
– IDE Interface
One Advanced Encryption System (AES) for AT32UC3A3256S, AT32UC3A3128S,
AT32UC3A364S, AT32UC3A4256S, AT32UC3A4128S and AT32UC3A364S
– 256-, 192-, 128-bit Key Algorithm, Compliant with FIPS PUB 197 Specifications
– Buffer Encryption/Decryption Capabilities
Universal Serial Bus (USB)
– High-Speed USB (480Mbit/s) Device/MiniHost with On-The-Go (OTG)
– Flexible End-Point Configuration and Management with Dedicated DMA Channels
– On-Chip Transceivers Including Pull-Ups
One 8-channel 10-bit Analog-To-Digital Converter, multiplexed with Digital IOs.
Two Three-Channel 16-bit Timer/Counter (TC)
Four Universal Synchronous/Asynchronous Receiver/Transmitters (USART)
– Fractionnal Baudrate Generator
32-bit AVR®
Microcontroller
AT32UC3A3256S
AT32UC3A3256
AT32UC3A3128S
AT32UC3A3128
AT32UC3A364S
AT32UC3A364
AT32UC3A4256S
AT32UC3A4256
AT32UC3A4128S
AT32UC3A4128
AT32UC3A464S
AT32UC3A464
Preliminary
32072C–03/2010
AT32UC3A3/A4
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– Support for SPI and LIN
– Optionnal support for IrDA, ISO7816, Hardware Handshaking, RS485 interfaces and Modem Line
Two Master/Slave Serial Peripheral Interfaces (SPI) with Chip Select Signals
One Synchronous Serial Protocol Controller
– Supports I2S and Generic Frame-Based Protocols
Two Master/Slave Two-Wire Interface (TWI), 400kbit/s I2C-compatible
16-bit Stereo Audio Bitstream
– Sample Rate Up to 50 KHz
On-Chip Debug System (JTAG interface)
– Nexus Class 2+, Runtime Control, Non-Intrusive Data and Program Trace
110 General Purpose Input/Output (GPIOs)
– Standard or High Speed mode
– Toggle capability: up to 66MHz
Packages
– 144-ball TFBGA, 11x11 mm, pitch 0.8 mm
– 144-pin LQFP, 22x22 mm, pitch 0.5 mm
– 100-ball VFBGA, 7x7 mm, pitch 0.65 mm
Single 3.3V Power Supply
2
32072C–AVR32–2010/03
AT32UC3A3/A4
1. Description
The AT32UC3A3/A4 is a complete System-On-Chip microcontroller based on the AVR32 UC
RISC processor running at frequencies up to 66MHz. AVR32 UC is a high-performance 32-bit
RISC microprocessor core, designed for cost-sensitive embedded applications, with particular
emphasis on low power consumption, high code density and high performance.
The processor implements a Memory Protection Unit (MPU) and a fast and flexible interrupt controller for supporting modern operating systems and real-time operating systems. Higher
computation capabilities are achievable using a rich set of DSP instructions.
The AT32UC3A3/A4 incorporates on-chip Flash and SRAM memories for secure and fast
access. 64 KBytes of SRAM are directly coupled to the AVR32 UC for performances optimization. Two blocks of 32 Kbytes SRAM are independently attached to the High Speed Bus Matrix,
allowing real ping-pong management.
The Peripheral Direct Memory Access Controller (PDCA) enables data transfers between
peripherals and memories without processor involvement. The PDCA drastically reduces processing overhead when transferring continuous and large data streams.
The Power Manager improves design flexibility and security: the on-chip Brown-Out Detector
monitors the power supply, the CPU runs from the on-chip RC oscillator or from one of external
oscillator sources, a Real-Time Clock and its associated timer keeps track of the time.
The device includes two sets of three identical 16-bit Timer/Counter (TC) channels. Each channel can be independently programmed to perform frequency measurement, event counting,
interval measurement, pulse generation, delay timing and pulse width modulation. 16-bit channels are combined to operate as 32-bit channels.
The AT32UC3A3/A4 also features many communication interfaces for communication intensive
applications like UART, SPI or TWI. Additionally, a flexible Synchronous Serial Controller (SSC)
is available. The SSC provides easy access to serial communication protocols and audio standards like I2S.
The AT32UC3A3/A4 includes a powerfull External Bus Interface to interface all standard memory device like SRAM, SDRAM, NAND Flash or parallel interfaces like LCD Module.
The peripheral set includes a High Speed MCI for SDIO/SD/MMC and a hardware encryption
module based on AES algorithm.
The device embeds a 10-bit ADC and a Digital Audio bistream DAC.
The Direct Memory Access controller (DMACA) allows high bandwidth data flows between high
speed peripherals (USB, External Memories, MMC, SDIO, ...) and through high speed internal
features (AES, internal memories).
The High-Speed (480MBit/s) USB 2.0 Device and Host interface supports several USB Classes
at the same time thanks to the rich Endpoint configuration. The On-The-Go (OTG) Host interface
allows device like a USB Flash disk or a USB printer to be directly connected to the processor.
This periphal has its own dedicated DMA and is perfect for Mass Storage application.
AT32UC3A3/A4 integrates a class 2+ Nexus 2.0 On-Chip Debug (OCD) System, with non-intrusive real-time trace, full-speed read/write memory access in addition to basic runtime control.
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32072C–AVR32–2010/03
AT32UC3A3/A4
2. Overview
Block Diagram
NEXUS
CLASS 2+
OCD
MCKO
MDO[5..0]
MSEO[1..0]
EVTI_N
EVTO_N
USB HS
INTERFACE
ID
VBOF
32KB RAM
HRAM0/1
32KB RAM
M
S
M
DMA
MEMORY PROTECTION UNIT
INSTR
INTERFACE
DATA
INTERFACE
M
M
LOCAL BUS
INTERFACE
S
S
S
HIGH SPEED
BUS MATRIX
M
S
DMA
GENERAL PURPOSE IOs
M
S
S
S
M
CONFIGURATION
PB
HSB
HSB-PB
BRIDGE B
REGISTERS BUS
HSB
PERIPHERAL
DMA
CONTROLLER
HSB-PB
BRIDGE A
EXTERNAL
INTERRUPT
CONTROLLER
PDC
EXTINT[7..0]
SCAN[7..0]
NMI
PDC
INTERRUPT
CONTROLLER
USART1
USART0
USART2
PDC
MULTIMEDIA CARD
& MEMORY STICK
INTERFACE
USART3
PDC
DATA[15..0]
PA
PB
PC
PX
DMA
CLK
SERIAL
PERIPHERAL
INTERFACE 0/1
PDC
PBA
PB
CMD[1..0]
VDDIN
SYNCHRONOUS
SERIAL
CONTROLLER
115 kHz
RCSYS
XOUT0
XIN1
XOUT1
CLOCK
GENERATOR
NCS[5..0]
NRD
NWAIT
NWE0
NWE1
NWE3
RAS
CAS
SDA10
SDCK
SDCKE
SDWE
CFCE1
CFCE2
CFRW
NANDOE
NANDWE
RXD
TXD
CLK
RTS, CTS
DSR, DTR, DCD, RI
RXD
TXD
CLK
RTS, CTS
TXD
PA
PB
PC
PX
SPCK
MISO, MOSI
NPCS0
NPCS[3..1]
TX_CLOCK, TX_FRAME_SYNC
TX_DATA
RX_CLOCK, RX_FRAME_SYNC
RX_DATA
TWCK
TWO-WIRE
INTERFACE 0/1
TWD
TWALM
OSC0
OSC1
PLL0
PLL1
RESET_N
POWER
MANAGER
GCLK[3..0]
A[2..0]
B[2..0]
CLK[2..0]
CLOCK
CONTROLLER
PDC
XIN0
32 KHz
OSC
DATA[15..0]
ADDR[23..0]
CLK
ANALOG TO
DIGITAL
CONVERTER
PDC
XIN32
XOUT32
WATCHDOG
TIMER
PDC
1V8
Regulator
VDDCORE
256/128/64
KB
FLASH
RXD
REAL TIME
COUNTER
GNDCORE
64 KB
SRAM
S
DMACA
AES
FAST GPIO
GENERAL PURPOSE IOs
USB_VBIAS
USB_VBUS
DMFS, DMHS
DPFS, DPHS
AVR32 UC
CPU
FLASH
CONTROLLER
JTAG
INTERFACE
EXTERNAL BUS INTERFACE
(SDRAM, STATIC MEMORY, COMPACT
FLASH & NAND FLASH)
TCK
TDO
TDI
TMS
Block Diagram
MEMORY INTERFACE
Figure 2-1.
PBB
2.1
AUDIO
BITSTREAM
DAC
SLEEP
CONTROLLER
RESET
CONTROLLER
AD[7..0]
DATA[1..0]
DATAN[1..0]
TIMER/COUNTER
0/1
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32072C–AVR32–2010/03
AT32UC3A3/A4
2.2
Configuration Summary
The table below lists all AT32UC3A3 memory and package configurations:
Table 2-1.
Memory and Package Configurations
Device
Flash
SRAM
AES
Package
AT32UC3A3256S
256KB
128KB
Yes
144-ball TFBGA/
144-lead LQFP
AT32UC3A3256
256KB
128KB
No
144-ball TFBGA/
144-lead LQFP
AT32UC3A3128S
128KB
128KB
Yes
144-ball TFBGA/
144-lead LQFP
AT32UC3A3128
128KB
128KB
No
144-ball TFBGA/
144-lead LQFP
AT32UC3A364S
64KB
128KB
Yes
144-ball TFBGA/
144-lead LQFP
AT32UC3A364
64KB
128KB
No
144-ball TFBGA/
144-lead LQFP
AT32UC3A4256S
256KB
128KB
Yes
144-ball VFBGA
AT32UC3A4256
256KB
128KB
No
144-ball VFBGA
AT32UC3A4128S
128KB
128KB
Yes
144-ball VFBGA
AT32UC3A4128
128KB
128KB
No
144-ball VFBGA
AT32UC3A464S
64KB
128KB
Yes
144-ball VFBGA
AT32UC3A464
64KB
128KB
No
144-ball VFBGA
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32072C–AVR32–2010/03
AT32UC3A3/A4
3. Package and Pinout
3.1
Package
The device pins are multiplexed with peripheral functions as described in the Peripheral Multiplexing on I/O Line section.
Figure 3-1.
TFBGA144 Pinout (top view)
1
2
3
4
5
6
7
8
9
10
11
12
A
B
C
D
E
F
G
H
J
K
L
M
Table 3-1.
TFBGA144 Package Pinout
1
2
3
4
5
6
7
8
9
10
11
12
A
PX40
PB00
PA28
PA27
PB03
PA29
PC02
PC04
PC05
DPHS
DMHS
USB_VBUS
B
PX10
PB11
PA31
PB02
VDDIO
PB04
PC03
VDDIO
USB_VBIAS
DMFS
GNDPLL
PA09
C
PX09
PX35
GNDIO
PB01
PX16
PX13
PA30
PB08
DPFS
GNDCORE
PA08
PA10
D
PX08
PX37
PX36
PX47
PX19
PX12
PB10
PA02
PA26
PA11
PB07
PB06
E
PX38
VDDIO
PX54
PX53
VDDIO
PX15
PB09
VDDIN
PA25
PA07
VDDCORE
PA12
F
PX39
PX07
PX06
PX49
PX48
GNDIO
GNDIO
PA06
PA04
PA05
PA13
PA16
G
PX00
PX05
PX59
PX50
PX51
GNDIO
GNDIO
PA23
PA24
PA03
PA00
PA01
H
PX01
VDDIO
PX58
PX57
VDDIO
PC01
PA17
VDDIO
PA21
PA22
VDDANA
PB05
J
PX04
PX02
PX34
PX56
PX55
PA14
PA15
PA19
PA20
TMS
TDO
RESET_N
K
PX03
PX44
GNDIO
PX46
PC00
PX17
PX52
PA18
PX27
GNDIO
PX29
TCK
L
PX11
GNDIO
PX45
PX20
VDDIO
PX18
PX43
VDDIN
PX26
PX28
GNDANA
TDI
M
PX22
PX41
PX42
PX14
PX21
PX23
PX24
PX25
PX32
PX31
PX30
PX33
6
32072C–AVR32–2010/03
AT32UC3A3/A4
Figure 3-2.
LQFP144 Pinout
108
73
109
72
144
37
1
Table 3-2.
36
LQFP144 Package Pinout
1
USB_VBUS
25
PB02
49
PX09
73
PX20
97
PX31
121
PB05
2
VDDIO
26
PA27
50
PX08
74
PX46
98
PC00
122
PA00
3
USB_VBIAS
27
PB01
51
PX38
75
PX50
99
PC01
123
PA01
4
GNDIO
28
PA28
52
PX39
76
PX57
100
PA14
124
PA05
5
DMHS
29
PA31
53
PX06
77
PX51
101
PA15
125
PA03
6
DPHS
30
PB00
54
PX07
78
PX56
102
GNDIO
126
PA04
7
GNDIO
31
PB11
55
PX00
79
PX55
103
VDDIO
127
PA06
8
DMFS
32
PX16
56
PX59
80
PX21
104
TMS
128
PA16
9
DPFS
33
PX13
57
PX58
81
VDDIO
105
TDO
129
PA13
10
VDDIO
34
PX12
58
PX05
82
GNDIO
106
RESET_N
130
VDDIO
11
PB08
35
PX19
59
PX01
83
PX17
107
TCK
131
GNDIO
12
PC05
36
PX40
60
PX04
84
PX18
108
TDI
132
PA12
13
PC04
37
PX10
61
PX34
85
PX23
109
PA21
133
PA07
14
PA30
38
PX35
62
PX02
86
PX24
110
PA22
134
PB06
15
PA02
39
PX47
63
PX03
87
PX52
111
PA23
135
PB07
16
PB10
40
PX15
64
VDDIO
88
PX43
112
PA24
136
PA11
17
PB09
41
PX48
65
GNDIO
89
PX27
113
PA20
137
PA08
18
PC02
42
PX53
66
PX44
90
PX26
114
PA19
138
PA10
19
PC03
43
PX49
67
PX11
91
PX28
115
PA18
139
PA09
20
GNDIO
44
PX36
68
PX14
92
PX25
116
PA17
140
GNDCORE
21
VDDIO
45
PX37
69
PX42
93
PX32
117
GNDANA
141
VDDCORE
22
PB04
46
PX54
70
PX45
94
PX29
118
VDDANA
142
VDDIN
23
PA29
47
GNDIO
71
PX41
95
PX33
119
PA25
143
VDDIN
24
PB03
48
VDDIO
72
PX22
96
PX30
120
PA26
144
GNDPLL
7
32072C–AVR32–2010/03
AT32UC3A3/A4
Figure 3-3.
VFBGA100 Pinout (top view)
1
2
3
4
5
6
7
8
9
10
A
B
C
D
E
F
G
H
J
K
Table 3-3.
VFBGA100 Package Pinout
1
2
3
4
5
6
7
8
9
10
A
PA28
PA27
PB04
PA30
PC02
PC03
PC05
DPHS
DMHS
USB_VBUS
B
PB00
PB01
PB02
PA29
VDDIO
VDDIO
PC04
DPFS
DMFS
GNDPLL
C
PB11
PA31
GNDIO
PB03
PB09
PB08
USB_VBIAS
GNDIO
PA11
PA10
PB10
PB07
PB06
PA09
VDDIN
VDDIN
PA04
VDDCORE
D
PX12
PX10
PX13
PX16/PX53
(1)
E
PA02/PX47
(1)
GNDIO
PX08
PX09
VDDIO
GNDIO
PA16
PA06/PA13
F
PX19/PX59(1)
VDDIO
PX06
PX07
GNDIO
VDDIO
PA26/PB05(1)
PA08
PA03
GNDCORE
G
PX05
PX01
PX02
PX00
PX30
PA23/PX46(1)
PA12/PA25(1)
PA00/PA18(1)
PA05
PA01/PA17(1)
H
PX04
PX21
GNDIO
PX25
PX31
PA22/PX20(1)
TMS
GNDANA
PA20/PX18(1)
PA07/PA19(1)
J
PX03
PX24
PX26
PX29
VDDIO
VDDANA
PA15/PX45(1)
TDO
RESET_N
PA24/PX17(1)
K
PX23
PX27
PX28
PX15/PX32(1)
PC00/PX14(1)
PC01
PA14/PX11(1)
TDI
TCK
PA21/PX22(1)
Note:
(1)
1. Those balls are physically connected to 2 GPIOs. Software must managed carrefully the GPIO
configuration to avoid electrical conflict
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32072C–AVR32–2010/03
AT32UC3A3/A4
3.2
Peripheral Multiplexing on I/O lines
Each GPIO line can be assigned to one of 4 peripheral functions; A, B, C, or D. The following
table defines how the I/O lines on the peripherals A, B, C, or D are multiplexed by the GPIO.
Table 3-4.
GPIO Controller Function Multiplexing
TFBGA
QFP
VFBGA
144
144
100
G11
G12
122
123
(1)
G8
G10
(1)
GPIO Pin
Function A
Function B
Function C
PA00
GPIO 0
USART0 - RTS
TC0 - CLK1
SPI1 - NPCS[3]
PA01
GPIO 1
USART0 - CTS
TC0 - A1
USART2 - RTS
PA02
GPIO 2
USART0 - CLK
TC0 - B1
SPI0 - NPCS[0]
D8
15
G10
125
F9
PA03
GPIO 3
USART0 - RXD
EIC - EXTINT[4]
ABDAC - DATA[0]
F9
126
E9
PA04
GPIO 4
USART0 - TXD
EIC - EXTINT[5]
ABDAC - DATAN[0]
F10
124
G9
PA05
GPIO 5
USART1 - RXD
TC1 - CLK0
USB - ID
PA06
GPIO 6
USART1 - TXD
TC1 - CLK1
USB - VBOF
PA07
GPIO 7
SPI0 - NPCS[3]
ABDAC - DATAN[0]
USART1 - CLK
F8
127
E1
(1)
Pin
E8
(1)
(1)
E10
133
H10
C11
137
F8
PA08
GPIO 8
SPI0 - SPCK
ABDAC - DATA[0]
TC1 - B1
B12
139
D8
PA09
GPIO 9
SPI0 - NPCS[0]
EIC - EXTINT[6]
TC1 - A1
C12
138
C10
PA10
GPIO 10
SPI0 - MOSI
USB - VBOF
TC1 - B0
D10
136
C9
E12
F11
J6
132
129
100
J7
101
F12
128
H7
K8
J8
J9
H9
H10
G8
G9
E9
116
115
114
113
109
110
111
112
119
PA11
GPIO 11
SPI0 - MISO
USB - ID
TC1 - A2
(1)
PA12
GPIO 12
USART1 - CTS
SPI0 - NPCS[2]
TC1 - A0
(1)
PA13
GPIO 13
USART1 - RTS
SPI0 - NPCS[1]
EIC - EXTINT[7]
(1)
PA14
GPIO 14
SPI0 - NPCS[1]
TWIMS0 - TWALM
TWIMS1 - TWCK
(1)
PA15
GPIO 15
MCI - CMD[1]
SPI1 - SPCK
TWIMS1 - TWD
PA16
GPIO 16
MCI - DATA[11]
SPI1 - MOSI
TC1 - CLK2
PA17
GPIO 17
MCI - DATA[10]
SPI1 - NPCS[1]
ADC - AD[7]
PA18
GPIO 18
MCI - DATA[9]
SPI1 - NPCS[2]
ADC - AD[6]
PA19
GPIO 19
MCI - DATA[8]
SPI1 - MISO
ADC - AD[5]
PA20
GPIO 20
EIC - NMI
SSC - RX_FRAME_SYNC
ADC - AD[4]
G7
E8
K7
J7
E7
G10
(1)
(1)
G8
H10
H9
(1)
K10
H6
(1)
(1)
PA21
GPIO 21
ADC - AD[0]
EIC - EXTINT[0]
USB - ID
(1)
PA22
GPIO 22
ADC - AD[1]
EIC - EXTINT[1]
USB - VBOF
(1)
PA23
GPIO 23
ADC - AD[2]
EIC - EXTINT[2]
ABDAC - DATA[1]
(1)
PA24
GPIO 24
ADC - AD[3]
EIC - EXTINT[3]
ABDAC - DATAN[1]
(1)
PA25
GPIO 25
TWIMS0 - TWD
TWIMS1 - TWALM
USART1 - DCD
G6
J10
G7
(1)
Function D
D9
120
F7 )
PA26
GPIO 26
TWIMS0 - TWCK
USART2 - CTS
USART1 - DSR
A4
26
A2
PA27
GPIO 27
MCI - CLK
SSC - RX_DATA
USART3 - RTS
MSI - SCLK
A3
28
A1
PA28
GPIO 28
MCI - CMD[0]
SSC - RX_CLOCK
USART3 - CTS
MSI - BS
A6
23
B4
PA29
GPIO 29
MCI - DATA[0]
USART3 - TXD
TC0 - CLK0
MSI - DATA[0]
C7
14
A4
PA30
GPIO 30
MCI - DATA[1]
USART3 - CLK
DMACA - DMAACK[0]
MSI - DATA[1]
B3
29
C2
PA31
GPIO 31
MCI - DATA[2]
USART2 - RXD
DMACA - DMARQ[0]
MSI - DATA[2]
A2
30
B1
PB00
GPIO 32
MCI - DATA[3]
USART2 - TXD
ADC - TRIGGER
MSI - DATA[3]
C4
27
B2
PB01
GPIO 33
MCI - DATA[4]
ABDAC - DATA[1]
EIC - SCAN[0]
MSI - INS
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Table 3-4.
GPIO Controller Function Multiplexing
B4
25
B3
PB02
GPIO 34
MCI - DATA[5]
ABDAC - DATAN[1]
EIC - SCAN[1]
A5
24
C4
PB03
GPIO 35
MCI - DATA[6]
USART2 - CLK
EIC - SCAN[2]
B6
22
A3
PB04
GPIO 36
MCI - DATA[7]
USART3 - RXD
EIC - SCAN[3]
H12
121
F7(1)
PB05
GPIO 37
USB - ID
TC0 - A0
EIC - SCAN[4]
D12
134
D7
PB06
GPIO 38
USB - VBOF
TC0 - B0
EIC - SCAN[5]
D11
135
D6
PB07
GPIO 39
SPI1 - SPCK
SSC - TX_CLOCK
EIC - SCAN[6]
C8
11
C6
PB08
GPIO 40
SPI1 - MISO
SSC - TX_DATA
EIC - SCAN[7]
E7
17
C5
PB09
GPIO 41
SPI1 - NPCS[0]
SSC - RX_DATA
EBI - NCS[4]
D7
16
D5
PB10
GPIO 42
SPI1 - MOSI
SSC - RX_FRAME_SYNC
EBI - NCS[5]
B2
31
C1
PB11
GPIO 43
USART1 - RXD
SSC - TX_FRAME_SYNC
PM - GCLK[1]
K5
98
K5(1)
PC00
GPIO 45
H6
99
K6
PC01
GPIO 46
A7
18
A5
PC02
GPIO 47
B7
19
A6
PC03
GPIO 48
A8
13
B7
PC04
GPIO 49
A9
12
A7
PC05
GPIO 50
G1
55
G4
PX00
GPIO 51
EBI - DATA[10]
USART0 - RXD
USART1 - RI
H1
59
G2
PX01
GPIO 52
EBI - DATA[9]
USART0 - TXD
USART1 - DTR
J2
62
G3
PX02
GPIO 53
EBI - DATA[8]
USART0 - CTS
PM - GCLK[0]
K1
63
J1
PX03
GPIO 54
EBI - DATA[7]
USART0 - RTS
J1
60
H1
PX04
GPIO 55
EBI - DATA[6]
USART1 - RXD
G2
58
G1
PX05
GPIO 56
EBI - DATA[5]
USART1 - TXD
F3
53
F3
PX06
GPIO 57
EBI - DATA[4]
USART1 - CTS
F2
54
F4
PX07
GPIO 58
EBI - DATA[3]
USART1 - RTS
D1
50
E3
PX08
GPIO 59
EBI - DATA[2]
USART3 - RXD
C1
49
E4
PX09
GPIO 60
EBI - DATA[1]
USART3 - TXD
B1
37
D2
PX10
GPIO 61
EBI - DATA[0]
USART2 - RXD
L1
67
K7(1)
PX11
GPIO 62
EBI - NWE1
USART2 - TXD
D6
34
D1
PX12
GPIO 63
EBI - NWE0
USART2 - CTS
MCI - CLK
C6
33
D3
PX13
GPIO 64
EBI - NRD
USART2 - RTS
MCI - CLK
M4
68
K5(1)
PX14
GPIO 65
EBI - NCS[1]
E6
40
K4(1)
PX15
GPIO 66
EBI - ADDR[19]
USART3 - RTS
TC0 - B0
C5
32
D4(1)
PX16
GPIO 67
EBI - ADDR[18]
USART3 - CTS
TC0 - A1
K6
83
J10(1)
PX17
GPIO 68
EBI - ADDR[17]
DMACA - DMARQ[1]
TC0 - B1
L6
84
H9(1)
PX18
GPIO 69
EBI - ADDR[16]
DMACA - DMAACK[1]
TC0 - A2
D5
35
F1(1)
PX19
GPIO 70
EBI - ADDR[15]
EIC - SCAN[0]
TC0 - B2
L4
73
H6(1)
PX20
GPIO 71
EBI - ADDR[14]
EIC - SCAN[1]
TC0 - CLK0
M5
80
H2
PX21
GPIO 72
EBI - ADDR[13]
EIC - SCAN[2]
TC0 - CLK1
M1
72
K10(1)
PX22
GPIO 73
EBI - ADDR[12]
EIC - SCAN[3]
TC0 - CLK2
TC0 - A0
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Table 3-4.
GPIO Controller Function Multiplexing
M6
85
K1
PX23
GPIO 74
EBI - ADDR[11]
EIC - SCAN[4]
SSC - TX_CLOCK
M7
86
J2
PX24
GPIO 75
EBI - ADDR[10]
EIC - SCAN[5]
SSC - TX_DATA
M8
92
H4
PX25
GPIO 76
EBI - ADDR[9]
EIC - SCAN[6]
SSC - RX_DATA
L9
90
J3
PX26
GPIO 77
EBI - ADDR[8]
EIC - SCAN[7]
SSC - RX_FRAME_SYNC
K9
89
K2
PX27
GPIO 78
EBI - ADDR[7]
SPI0 - MISO
SSC - TX_FRAME_SYNC
L10
91
K3
PX28
GPIO 79
EBI - ADDR[6]
SPI0 - MOSI
SSC - RX_CLOCK
K11
94
J4
PX29
GPIO 80
EBI - ADDR[5]
SPI0 - SPCK
M11
96
G5
PX30
GPIO 81
EBI - ADDR[4]
SPI0 - NPCS[0]
M10
97
H5
PX31
GPIO 82
EBI - ADDR[3]
SPI0 - NPCS[1]
M9
93
K4(1)
PX32
GPIO 83
EBI - ADDR[2]
SPI0 - NPCS[2]
M12
95
PX33
GPIO 84
EBI - ADDR[1]
SPI0 - NPCS[3]
J3
61
PX34
GPIO 85
EBI - ADDR[0]
SPI1 - MISO
PM - GCLK[0]
C2
38
PX35
GPIO 86
EBI - DATA[15]
SPI1 - MOSI
PM - GCLK[1]
D3
44
PX36
GPIO 87
EBI - DATA[14]
SPI1 - SPCK
PM - GCLK[2]
D2
45
PX37
GPIO 88
EBI - DATA[13]
SPI1 - NPCS[0]
PM - GCLK[3]
E1
51
PX38
GPIO 89
EBI - DATA[12]
SPI1 - NPCS[1]
USART1 - DCD
F1
52
PX39
GPIO 90
EBI - DATA[11]
SPI1 - NPCS[2]
USART1 - DSR
A1
36
PX40
GPIO 91
M2
71
PX41
GPIO 92
EBI - CAS
M3
69
PX42
GPIO 93
EBI - RAS
L7
88
PX43
GPIO 94
EBI - SDA10
USART1 - RI
K2
66
PX44
GPIO 95
EBI - SDWE
USART1 - DTR
L3
70
J7(1)
PX45
GPIO 96
EBI - SDCK
K4
74
G6(1)
PX46
GPIO 97
EBI - SDCKE
D4
39
E1(1)
PX47
GPIO 98
EBI - NANDOE
ADC - TRIGGER
MCI - DATA[11]
F5
41
PX48
GPIO 99
EBI - ADDR[23]
USB - VBOF
MCI - DATA[10]
F4
43
PX49
GPIO 100
EBI - CFRNW
USB - ID
MCI - DATA[9]
G4
75
PX50
GPIO 101
EBI - CFCE2
TC1 - B2
MCI - DATA[8]
G5
77
PX51
GPIO 102
EBI - CFCE1
DMACA - DMAACK[0]
MCI - DATA[15]
K7
87
PX52
GPIO 103
EBI - NCS[3]
DMACA - DMARQ[0]
MCI - DATA[14]
E4
42
PX53
GPIO 104
EBI - NCS[2]
E3
46
PX54
GPIO 105
EBI - NWAIT
USART3 - TXD
MCI - DATA[12]
J5
79
PX55
GPIO 106
EBI - ADDR[22]
EIC - SCAN[3]
USART2 - RXD
J4
78
PX56
GPIO 107
EBI - ADDR[21]
EIC - SCAN[2]
USART2 - TXD
H4
76
PX57
GPIO 108
EBI - ADDR[20]
EIC - SCAN[1]
USART3 - RXD
H3
57
PX58
GPIO 109
EBI - NCS[0]
EIC - SCAN[0]
USART3 - TXD
G3
56
PX59
GPIO 110
EBI - NANDWE
D4(1)
F1(1)
Note:
MCI - CLK
MCI - DATA[13]
MCI - CMD[1]
1. Those balls are physically connected to 2 GPIOs. Software must managed carrefully the GPIO
configuration to avoid electrical conflict
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3.2.1
Oscillator Pinout
Table 3-5.
Oscillator Pinout
TFBGA144
QFP144
VFBGA100
Pin name
Oscillator pin
A7
18
A5
PC02
XIN0
B7
19
A6
PC03
XOUT0
A8
13
B7
PC04
XIN1
A9
12
A7
PC05
XIN1
PC00
XIN32
PC01
XOUT32
K5
98
H6
99
Note:
3.2.2
K5
K6
1. This ball is physically connected to 2 GPIOs. Software must managed carrefully the GPIO configuration to avoid electrical conflict
JTAG port connections
Table 3-6.
3.2.3
(1)
JTAG Pinout
TFBGA144
QFP144
VFBGA100
Pin name
JTAG pin
K12
107
K9
TCK
TCK
L12
108
K8
TDI
TDI
J11
105
J8
TDO
TDO
J10
104
H7
TMS
TMS
Nexus OCD AUX port connections
If the OCD trace system is enabled, the trace system will take control over a number of pins, irrespective of the GPIO configuration. Three differents OCD trace pin mappings are possible,
depending on the configuration of the OCD AXS register. For details, see the AVR32 UC Technical Reference Manual.
Table 3-7.
Nexus OCD AUX port connections
Pin
AXS=0
AXS=1
AXS=2
EVTI_N
PB05
PA08
PX00
MDO[5]
PA00
PX56
PX06
MDO[4]
PA01
PX57
PX05
MDO[3]
PA03
PX58
PX04
MDO[2]
PA16
PA24
PX03
MDO[1]
PA13
PA23
PX02
MDO[0]
PA12
PA22
PX01
MSEO[1]
PA10
PA07
PX08
MSEO[0]
PA11
PX55
PX07
MCKO
PB07
PX00
PB09
EVTO_N
PB06
PB06
PB06
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3.3
Signal Descriptions
The following table gives details on signal name classified by peripheral.
Table 3-8.
Signal Description List
Signal Name
Function
Type
Active
Level
Comments
Power
VDDIO
I/O Power Supply
Power
3.0 to 3.6V
VDDANA
Analog Power Supply
Power
3.0 to 3.6V
VDDIN
Voltage Regulator Input Supply
Power
3.0 to 3.6V
VDDCORE
Voltage Regulator Output for Digital Supply
Power
Output
1.65 to 1.95 V
GNDANA
Analog Ground
Ground
GNDIO
I/O Ground
Ground
GNDCORE
Digital Ground
Ground
GNDPLL
PLL Ground
Ground
Clocks, Oscillators, and PLL’s
XIN0, XIN1, XIN32
Crystal 0, 1, 32 Input
Analog
XOUT0, XOUT1,
XOUT32
Crystal 0, 1, 32 Output
Analog
JTAG
TCK
Test Clock
Input
TDI
Test Data In
Input
TDO
Test Data Out
TMS
Test Mode Select
Output
Input
Auxiliary Port - AUX
MCKO
Trace Data Output Clock
Output
MDO[5:0]
Trace Data Output
Output
MSEO[1:0]
Trace Frame Control
Output
EVTI_N
Event In
Output
Low
EVTO_N
Event Out
Output
Low
Power Manager - PM
GCLK[3:0]
Generic Clock Pins
Output
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Table 3-8.
Signal Description List
Signal Name
Function
Type
Active
Level
RESET_N
Reset Pin
Input
Low
Comments
DMA Controller - DMACA (optional)
DMAACK[1:0]
DMA Acknowledge
DMARQ[1:0]
DMA Requests
Output
Input
External Interrupt Controller - EIC
EXTINT[7:0]
External Interrupt Pins
Input
SCAN[7:0]
Keypad Scan Pins
NMI
Non-Maskable Interrupt Pin
Output
Input
Low
General Purpose Input/Output pin - GPIOA, GPIOB, GPIOC, GPIOX
PA[31:0]
Parallel I/O Controller GPIO port A
I/O
PB[11:0]
Parallel I/O Controller GPIO port B
I/O
PC[5:0]
Parallel I/O Controller GPIO port C
I/O
PX[59:0]
Parallel I/O Controller GPIO port X
I/O
External Bus Interface - EBI
ADDR[23:0]
Address Bus
Output
CAS
Column Signal
Output
Low
CFCE1
Compact Flash 1 Chip Enable
Output
Low
CFCE2
Compact Flash 2 Chip Enable
Output
Low
CFRNW
Compact Flash Read Not Write
Output
DATA[15:0]
Data Bus
NANDOE
NAND Flash Output Enable
Output
Low
NANDWE
NAND Flash Write Enable
Output
Low
NCS[5:0]
Chip Select
Output
Low
NRD
Read Signal
Output
Low
NWAIT
External Wait Signal
Input
Low
NWE0
Write Enable 0
Output
Low
NWE1
Write Enable 1
Output
Low
RAS
Row Signal
Output
Low
I/O
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Table 3-8.
Signal Description List
Signal Name
Function
Type
SDA10
SDRAM Address 10 Line
Output
SDCK
SDRAM Clock
Output
SDCKE
SDRAM Clock Enable
Output
SDWE
SDRAM Write Enable
Output
Active
Level
Comments
Low
MultiMedia Card Interface - MCI
CLK
Multimedia Card Clock
Output
CMD[1:0]
Multimedia Card Command
I/O
DATA[15:0]
Multimedia Card Data
I/O
Memory Stick Interface - MSI
SCLK
Memory Stick Clock
Output
BS
Memory Stick Command
I/O
DATA[3:0]
Multimedia Card Data
I/O
Serial Peripheral Interface - SPI0, SPI1
MISO
Master In Slave Out
I/O
MOSI
Master Out Slave In
I/O
NPCS[3:0]
SPI Peripheral Chip Select
I/O
SPCK
Clock
Low
Output
Synchronous Serial Controller - SSC
RX_CLOCK
SSC Receive Clock
I/O
RX_DATA
SSC Receive Data
Input
RX_FRAME_SYNC
SSC Receive Frame Sync
I/O
TX_CLOCK
SSC Transmit Clock
I/O
TX_DATA
SSC Transmit Data
Output
TX_FRAME_SYNC
SSC Transmit Frame Sync
I/O
Timer/Counter - TC0, TC1
A0
Channel 0 Line A
I/O
A1
Channel 1 Line A
I/O
A2
Channel 2 Line A
I/O
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Table 3-8.
Signal Description List
Signal Name
Function
Type
B0
Channel 0 Line B
I/O
B1
Channel 1 Line B
I/O
B2
Channel 2 Line B
I/O
CLK0
Channel 0 External Clock Input
Input
CLK1
Channel 1 External Clock Input
Input
CLK2
Channel 2 External Clock Input
Input
Active
Level
Comments
Two-wire Interface - TWI0, TWI1
TWCK
Serial Clock
I/O
TWD
Serial Data
I/O
TWALM
SMBALERT signal
I/O
Universal Synchronous Asynchronous Receiver Transmitter - USART0, USART1, USART2, USART3
CLK
Clock
I/O
CTS
Clear To Send
DCD
Data Carrier Detect
Only USART1
DSR
Data Set Ready
Only USART1
DTR
Data Terminal Ready
Only USART1
RI
Ring Indicator
Only USART1
RTS
Request To Send
RXD
Receive Data
Input
TXD
Transmit Data
Output
Input
Output
Analog to Digital Converter - ADC
AD0 - AD7
Analog input pins
Analog
input
Audio Bitstream DAC (ABDAC)
DATA0-DATA1
D/A Data out
Output
DATAN0-DATAN1
D/A Data inverted out
Output
Universal Serial Bus Device - USB
DMFS
USB Full Speed Data -
Analog
DPFS
USB Full Speed Data +
Analog
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Table 3-8.
Signal Description List
Signal Name
Function
Type
DMHS
USB High Speed Data -
Analog
DPHS
USB High Speed Data +
Analog
USB_VBIAS
USB VBIAS reference
Analog
USB_VBUS
USB VBUS for OTG feature
Output
VBOF
USB VBUS on/off bus power control port
Output
ID
ID Pin fo the USB bus
Active
Level
Comments
Connect to the ground through a
6810 ohms (+/- 1%) resistor in
parallel with a 10pf capacitor.
If USB hi-speed feature is not
required, leave this pin
unconnected to save power
Input
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3.4
3.4.1
I/O Line Considerations
JTAG Pins
TMS and TDI pins have pull-up resistors. TDO pin is an output, driven at up to VDDIO, and has
no pull-up resistor.
3.4.2
RESET_N Pin
The RESET_N pin is a schmitt input and integrates a permanent pull-up resistor to VDDIO. As
the product integrates a power-on reset cell, the RESET_N pin can be left unconnected in case
no reset from the system needs to be applied to the product.
3.4.3
TWI Pins
When these pins are used for TWI, the pins are open-drain outputs with slew-rate limitation and
inputs with inputs with spike filtering. When used as GPIO pins or used for other peripherals, the
pins have the same characteristics as other GPIO pins.
3.4.4
GPIO Pins
All the I/O lines integrate a programmable pull-up resistor. Programming of this pull-up resistor is
performed independently for each I/O line through the I/O Controller. After reset, I/O lines default
as inputs with pull-up resistors disabled, except when indicated otherwise in the column “Reset
State” of the I/O Controller multiplexing tables.
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3.5
3.5.1
Power Considerations
Power Supplies
The AT32UC3A3 has several types of power supply pins:
•
•
•
•
VDDIO: Powers I/O lines. Voltage is 3.3V nominal
VDDANA: Powers the ADC. Voltage is 3.3V nominal
VDDIN: Input voltage for the voltage regulator. Voltage is 3.3V nominal
VDDCORE: Output voltage from regulator for filtering purpose and provides the supply to the
core, memories, and peripherals. Voltage is 1.8V nominal
The ground pin GNDCORE is common to VDDCORE and VDDIN. The ground pin for VDDANA
is GNDANA. The ground pins for VDDIO are GNDIO.
Refer to Electrical Characteristics chapter for power consumption on the various supply pins.
3.5.2
Voltage Regulator
The AT32UC3A3 embeds a voltage regulator that converts from 3.3V to 1.8V with a load of up
to 100 mA. The regulator takes its input voltage from VDDIN, and supplies the output voltage on
VDDCORE and powers the core, memories and peripherals.
Adequate output supply decoupling is mandatory for VDDCORE to reduce ripple and avoid
oscillations.
The best way to achieve this is to use two capacitors in parallel between VDDCORE and
GNDCORE:
• One external 470pF (or 1nF) NPO capacitor (COUT1) should be connected as close to the
chip as possible.
• One external 2.2µF (or 3.3µF) X7R capacitor (COUT2).
Adequate input supply decoupling is mandatory for VDDIN in order to improve startup stability
and reduce source voltage drop.
The input decoupling capacitor should be placed close to the chip, e.g., two capacitors can be
used in parallel (1nF NPO and 4.7µF X7R).
3.3V
VDDIN
CIN2
CIN1
1.8V
1.8V
Regulator
VDDCORE
COUT2
COUT1
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4. Processor and Architecture
Rev: 1.4.2.0
This chapter gives an overview of the AVR32UC CPU. AVR32UC is an implementation of the
AVR32 architecture. A summary of the programming model, instruction set, and MPU is presented. For further details, see the AVR32 Architecture Manual and the AVR32UC Technical
Reference Manual.
4.1
Features
• 32-bit load/store AVR32A RISC architecture
–
–
–
–
–
15 general-purpose 32-bit registers
32-bit Stack Pointer, Program Counter and Link Register reside in register file
Fully orthogonal instruction set
Privileged and unprivileged modes enabling efficient and secure Operating Systems
Innovative instruction set together with variable instruction length ensuring industry leading
code density
– DSP extention with saturating arithmetic, and a wide variety of multiply instructions
• 3-stage pipeline allows one instruction per clock cycle for most instructions
– Byte, halfword, word and double word memory access
– Multiple interrupt priority levels
• MPU allows for operating systems with memory protection
4.2
AVR32 Architecture
AVR32 is a high-performance 32-bit RISC microprocessor architecture, designed for cost-sensitive embedded applications, with particular emphasis on low power consumption and high code
density. In addition, the instruction set architecture has been tuned to allow a variety of microarchitectures, enabling the AVR32 to be implemented as low-, mid-, or high-performance
processors. AVR32 extends the AVR family into the world of 32- and 64-bit applications.
Through a quantitative approach, a large set of industry recognized benchmarks has been compiled and analyzed to achieve the best code density in its class. In addition to lowering the
memory requirements, a compact code size also contributes to the core’s low power characteristics. The processor supports byte and halfword data types without penalty in code size and
performance.
Memory load and store operations are provided for byte, halfword, word, and double word data
with automatic sign- or zero extension of halfword and byte data. The C-compiler is closely
linked to the architecture and is able to exploit code optimization features, both for size and
speed.
In order to reduce code size to a minimum, some instructions have multiple addressing modes.
As an example, instructions with immediates often have a compact format with a smaller immediate, and an extended format with a larger immediate. In this way, the compiler is able to use
the format giving the smallest code size.
Another feature of the instruction set is that frequently used instructions, like add, have a compact format with two operands as well as an extended format with three operands. The larger
format increases performance, allowing an addition and a data move in the same instruction in a
single cycle. Load and store instructions have several different formats in order to reduce code
size and speed up execution.
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The register file is organized as sixteen 32-bit registers and includes the Program Counter, the
Link Register, and the Stack Pointer. In addition, register R12 is designed to hold return values
from function calls and is used implicitly by some instructions.
4.3
The AVR32UC CPU
The AVR32UC CPU targets low- and medium-performance applications, and provides an
advanced OCD system, no caches, and a Memory Protection Unit (MPU). Java acceleration
hardware is not implemented.
AVR32UC provides three memory interfaces, one High Speed Bus master for instruction fetch,
one High Speed Bus master for data access, and one High Speed Bus slave interface allowing
other bus masters to access data RAMs internal to the CPU. Keeping data RAMs internal to the
CPU allows fast access to the RAMs, reduces latency, and guarantees deterministic timing.
Also, power consumption is reduced by not needing a full High Speed Bus access for memory
accesses. A dedicated data RAM interface is provided for communicating with the internal data
RAMs.
A local bus interface is provided for connecting the CPU to device-specific high-speed systems,
such as floating-point units and fast GPIO ports. This local bus has to be enabled by writing the
LOCEN bit in the CPUCR system register. The local bus is able to transfer data between the
CPU and the local bus slave in a single clock cycle. The local bus has a dedicated memory
range allocated to it, and data transfers are performed using regular load and store instructions.
Details on which devices that are mapped into the local bus space is given in the Memories
chapter of this data sheet.
Figure 4-1 on page 22 displays the contents of AVR32UC.
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OCD interface
Reset interface
Overview of the AVR32UC CPU
Interrupt controller interface
Figure 4-1.
OCD
system
Power/
Reset
control
AVR32UC CPU pipeline
MPU
4.3.1
CPU Local
Bus
master
Data RAM interface
High
Speed
Bus slave
CPU Local Bus
High
Speed
Bus
master
High Speed Bus
High Speed Bus
High Speed Bus master
High Speed Bus
Data memory controller
Instruction memory controller
Pipeline Overview
AVR32UC has three pipeline stages, Instruction Fetch (IF), Instruction Decode (ID), and Instruction Execute (EX). The EX stage is split into three parallel subsections, one arithmetic/logic
(ALU) section, one multiply (MUL) section, and one load/store (LS) section.
Instructions are issued and complete in order. Certain operations require several clock cycles to
complete, and in this case, the instruction resides in the ID and EX stages for the required number of clock cycles. Since there is only three pipeline stages, no internal data forwarding is
required, and no data dependencies can arise in the pipeline.
Figure 4-2 on page 23 shows an overview of the AVR32UC pipeline stages.
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Figure 4-2.
The AVR32UC Pipeline
Multiply unit
MUL
IF
ID
Pref etch unit
Decode unit
Regf ile
Read
A LU
LS
4.3.2
Regf ile
w rite
A LU unit
Load-store
unit
AVR32A Microarchitecture Compliance
AVR32UC implements an AVR32A microarchitecture. The AVR32A microarchitecture is targeted at cost-sensitive, lower-end applications like smaller microcontrollers. This
microarchitecture does not provide dedicated hardware registers for shadowing of register file
registers in interrupt contexts. Additionally, it does not provide hardware registers for the return
address registers and return status registers. Instead, all this information is stored on the system
stack. This saves chip area at the expense of slower interrupt handling.
Upon interrupt initiation, registers R8-R12 are automatically pushed to the system stack. These
registers are pushed regardless of the priority level of the pending interrupt. The return address
and status register are also automatically pushed to stack. The interrupt handler can therefore
use R8-R12 freely. Upon interrupt completion, the old R8-R12 registers and status register are
restored, and execution continues at the return address stored popped from stack.
The stack is also used to store the status register and return address for exceptions and scall.
Executing the rete or rets instruction at the completion of an exception or system call will pop
this status register and continue execution at the popped return address.
4.3.3
Java Support
AVR32UC does not provide Java hardware acceleration.
4.3.4
Memory Protection
The MPU allows the user to check all memory accesses for privilege violations. If an access is
attempted to an illegal memory address, the access is aborted and an exception is taken. The
MPU in AVR32UC is specified in the AVR32UC Technical Reference manual.
4.3.5
Unaligned Reference Handling
AVR32UC does not support unaligned accesses, except for doubleword accesses. AVR32UC is
able to perform word-aligned st.d and ld.d. Any other unaligned memory access will cause an
address exception. Doubleword-sized accesses with word-aligned pointers will automatically be
performed as two word-sized accesses.
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The following table shows the instructions with support for unaligned addresses. All other
instructions require aligned addresses.
Table 4-1.
4.3.6
Instructions with Unaligned Reference Support
Instruction
Supported alignment
ld.d
Word
st.d
Word
Unimplemented Instructions
The following instructions are unimplemented in AVR32UC, and will cause an Unimplemented
Instruction Exception if executed:
• All SIMD instructions
• All coprocessor instructions if no coprocessors are present
• retj, incjosp, popjc, pushjc
• tlbr, tlbs, tlbw
• cache
4.3.7
CPU and Architecture Revision
Three major revisions of the AVR32UC CPU currently exist.
The Architecture Revision field in the CONFIG0 system register identifies which architecture
revision is implemented in a specific device.
AVR32UC CPU revision 3 is fully backward-compatible with revisions 1 and 2, ie. code compiled
for revision 1 or 2 is binary-compatible with revision 3 CPUs.
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4.4
4.4.1
Programming Model
Register File Configuration
The AVR32UC register file is shown below.
Figure 4-3.
The AVR32UC Register File
Application
Supervisor
INT0
Bit 31
Bit 31
Bit 31
Bit 0
Bit 0
INT1
Bit 0
INT2
Bit 31
Bit 0
INT3
Bit 31
Bit 0
Bit 31
Bit 0
Exception
NMI
Bit 31
Bit 31
Bit 0
Secure
Bit 0
Bit 31
Bit 0
PC
LR
SP_APP
R12
R11
R10
R9
R8
INT0PC
R7
INT1PC
R6
FINTPC
R5
SMPC
R4
R3
R2
R1
R0
PC
LR
SP_SYS
R12
R11
R10
R9
R8
INT0PC
R7
INT1PC
R6
FINTPC
R5
SMPC
R4
R3
R2
R1
R0
PC
LR
SP_SYS
R12
R11
R10
R9
R8
INT0PC
R7
INT1PC
R6
FINTPC
R5
SMPC
R4
R3
R2
R1
R0
PC
LR
SP_SYS
R12
R11
R10
R9
R8
INT0PC
R7
INT1PC
R6
FINTPC
R5
SMPC
R4
R3
R2
R1
R0
PC
LR
SP_SYS
R12
R11
R10
R9
R8
INT0PC
R7
INT1PC
R6
FINTPC
R5
SMPC
R4
R3
R2
R1
R0
PC
LR
SP_SYS
R12
R11
R10
R9
R8
INT0PC
R7
INT1PC
R6
FINTPC
R5
SMPC
R4
R3
R2
R1
R0
PC
LR
SP_SYS
R12
R11
R10
R9
R8
INT0PC
R7
INT1PC
R6
FINTPC
R5
SMPC
R4
R3
R2
R1
R0
PC
LR
SP_SYS
R12
R11
R10
R9
R8
INT0PC
R7
INT1PC
R6
FINTPC
R5
SMPC
R4
R3
R2
R1
R0
PC
LR
SP_SEC
R12
R11
R10
R9
R8
INT0PC
R7
INT1PC
R6
FINTPC
R5
SMPC
R4
R3
R2
R1
R0
SR
SR
SR
SR
SR
SR
SR
SR
SR
SS_STATUS
SS_ADRF
SS_ADRR
SS_ADR0
SS_ADR1
SS_SP_SYS
SS_SP_APP
SS_RAR
SS_RSR
4.4.2
Status Register Configuration
The Status Register (SR) is split into two halfwords, one upper and one lower, see Figure 4-4 on
page 25 and Figure 4-5 on page 26. The lower word contains the C, Z, N, V, and Q condition
code flags and the R, T, and L bits, while the upper halfword contains information about the
mode and state the processor executes in. Refer to the AVR32 Architecture Manual for details.
Figure 4-4.
The Status Register High Halfword
Bit 31
Bit 16
-
LC
1
-
-
DM
D
-
M2
M1
M0
EM
I3M
I2M
FE
I1M
I0M
GM
0
0
0
0
0
0
0
0
0
1
1
0
0
0
0
1
Bit name
Initial value
Global Interrupt Mask
Interrupt Level 0 Mask
Interrupt Level 1 Mask
Interrupt Level 2 Mask
Interrupt Level 3 Mask
Exception Mask
Mode Bit 0
Mode Bit 1
Mode Bit 2
Reserved
Debug State
Debug State Mask
Reserved
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Figure 4-5.
The Status Register Low Halfword
Bit 15
Bit 0
-
T
-
-
-
-
-
-
-
-
L
Q
V
N
Z
C
Bit name
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Initial value
Carry
Zero
Sign
Overflow
Saturation
Lock
Reserved
Scratch
Reserved
4.4.3
4.4.3.1
Processor States
Normal RISC State
The AVR32 processor supports several different execution contexts as shown in Table 4-2 on
page 26.
Table 4-2.
Overview of Execution Modes, their Priorities and Privilege Levels.
Priority
Mode
Security
Description
1
Non Maskable Interrupt
Privileged
Non Maskable high priority interrupt mode
2
Exception
Privileged
Execute exceptions
3
Interrupt 3
Privileged
General purpose interrupt mode
4
Interrupt 2
Privileged
General purpose interrupt mode
5
Interrupt 1
Privileged
General purpose interrupt mode
6
Interrupt 0
Privileged
General purpose interrupt mode
N/A
Supervisor
Privileged
Runs supervisor calls
N/A
Application
Unprivileged
Normal program execution mode
Mode changes can be made under software control, or can be caused by external interrupts or
exception processing. A mode can be interrupted by a higher priority mode, but never by one
with lower priority. Nested exceptions can be supported with a minimal software overhead.
When running an operating system on the AVR32, user processes will typically execute in the
application mode. The programs executed in this mode are restricted from executing certain
instructions. Furthermore, most system registers together with the upper halfword of the status
register cannot be accessed. Protected memory areas are also not available. All other operating
modes are privileged and are collectively called System Modes. They have full access to all privileged and unprivileged resources. After a reset, the processor will be in supervisor mode.
4.4.3.2
Debug State
The AVR32 can be set in a debug state, which allows implementation of software monitor routines that can read out and alter system information for use during application development. This
implies that all system and application registers, including the status registers and program
counters, are accessible in debug state. The privileged instructions are also available.
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All interrupt levels are by default disabled when debug state is entered, but they can individually
be switched on by the monitor routine by clearing the respective mask bit in the status register.
Debug state can be entered as described in the AVR32UC Technical Reference Manual.
Debug state is exited by the retd instruction.
4.4.4
System Registers
The system registers are placed outside of the virtual memory space, and are only accessible
using the privileged mfsr and mtsr instructions. The table below lists the system registers specified in the AVR32 architecture, some of which are unused in AVR32UC. The programmer is
responsible for maintaining correct sequencing of any instructions following a mtsr instruction.
For detail on the system registers, refer to the AVR32UC Technical Reference Manual.
Table 4-3.
System Registers
Reg #
Address
Name
Function
0
0
SR
Status Register
1
4
EVBA
Exception Vector Base Address
2
8
ACBA
Application Call Base Address
3
12
CPUCR
CPU Control Register
4
16
ECR
Exception Cause Register
5
20
RSR_SUP
Unused in AVR32UC
6
24
RSR_INT0
Unused in AVR32UC
7
28
RSR_INT1
Unused in AVR32UC
8
32
RSR_INT2
Unused in AVR32UC
9
36
RSR_INT3
Unused in AVR32UC
10
40
RSR_EX
Unused in AVR32UC
11
44
RSR_NMI
Unused in AVR32UC
12
48
RSR_DBG
Return Status Register for Debug mode
13
52
RAR_SUP
Unused in AVR32UC
14
56
RAR_INT0
Unused in AVR32UC
15
60
RAR_INT1
Unused in AVR32UC
16
64
RAR_INT2
Unused in AVR32UC
17
68
RAR_INT3
Unused in AVR32UC
18
72
RAR_EX
Unused in AVR32UC
19
76
RAR_NMI
Unused in AVR32UC
20
80
RAR_DBG
Return Address Register for Debug mode
21
84
JECR
Unused in AVR32UC
22
88
JOSP
Unused in AVR32UC
23
92
JAVA_LV0
Unused in AVR32UC
24
96
JAVA_LV1
Unused in AVR32UC
25
100
JAVA_LV2
Unused in AVR32UC
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Table 4-3.
System Registers (Continued)
Reg #
Address
Name
Function
26
104
JAVA_LV3
Unused in AVR32UC
27
108
JAVA_LV4
Unused in AVR32UC
28
112
JAVA_LV5
Unused in AVR32UC
29
116
JAVA_LV6
Unused in AVR32UC
30
120
JAVA_LV7
Unused in AVR32UC
31
124
JTBA
Unused in AVR32UC
32
128
JBCR
Unused in AVR32UC
33-63
132-252
Reserved
Reserved for future use
64
256
CONFIG0
Configuration register 0
65
260
CONFIG1
Configuration register 1
66
264
COUNT
Cycle Counter register
67
268
COMPARE
Compare register
68
272
TLBEHI
Unused in AVR32UC
69
276
TLBELO
Unused in AVR32UC
70
280
PTBR
Unused in AVR32UC
71
284
TLBEAR
Unused in AVR32UC
72
288
MMUCR
Unused in AVR32UC
73
292
TLBARLO
Unused in AVR32UC
74
296
TLBARHI
Unused in AVR32UC
75
300
PCCNT
Unused in AVR32UC
76
304
PCNT0
Unused in AVR32UC
77
308
PCNT1
Unused in AVR32UC
78
312
PCCR
Unused in AVR32UC
79
316
BEAR
Bus Error Address Register
80
320
MPUAR0
MPU Address Register region 0
81
324
MPUAR1
MPU Address Register region 1
82
328
MPUAR2
MPU Address Register region 2
83
332
MPUAR3
MPU Address Register region 3
84
336
MPUAR4
MPU Address Register region 4
85
340
MPUAR5
MPU Address Register region 5
86
344
MPUAR6
MPU Address Register region 6
87
348
MPUAR7
MPU Address Register region 7
88
352
MPUPSR0
MPU Privilege Select Register region 0
89
356
MPUPSR1
MPU Privilege Select Register region 1
90
360
MPUPSR2
MPU Privilege Select Register region 2
91
364
MPUPSR3
MPU Privilege Select Register region 3
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Table 4-3.
4.5
System Registers (Continued)
Reg #
Address
Name
Function
92
368
MPUPSR4
MPU Privilege Select Register region 4
93
372
MPUPSR5
MPU Privilege Select Register region 5
94
376
MPUPSR6
MPU Privilege Select Register region 6
95
380
MPUPSR7
MPU Privilege Select Register region 7
96
384
MPUCRA
Unused in this version of AVR32UC
97
388
MPUCRB
Unused in this version of AVR32UC
98
392
MPUBRA
Unused in this version of AVR32UC
99
396
MPUBRB
Unused in this version of AVR32UC
100
400
MPUAPRA
MPU Access Permission Register A
101
404
MPUAPRB
MPU Access Permission Register B
102
408
MPUCR
MPU Control Register
103-191
448-764
Reserved
Reserved for future use
192-255
768-1020
IMPL
IMPLEMENTATION DEFINED
Exceptions and Interrupts
AVR32UC incorporates a powerful exception handling scheme. The different exception sources,
like Illegal Op-code and external interrupt requests, have different priority levels, ensuring a welldefined behavior when multiple exceptions are received simultaneously. Additionally, pending
exceptions of a higher priority class may preempt handling of ongoing exceptions of a lower priority class.
When an event occurs, the execution of the instruction stream is halted, and execution control is
passed to an event handler at an address specified in Table 4-4 on page 32. Most of the handlers are placed sequentially in the code space starting at the address specified by EVBA, with
four bytes between each handler. This gives ample space for a jump instruction to be placed
there, jumping to the event routine itself. A few critical handlers have larger spacing between
them, allowing the entire event routine to be placed directly at the address specified by the
EVBA-relative offset generated by hardware. All external interrupt sources have autovectored
interrupt service routine (ISR) addresses. This allows the interrupt controller to directly specify
the ISR address as an address relative to EVBA. The autovector offset has 14 address bits, giving an offset of maximum 16384 bytes. The target address of the event handler is calculated as
(EVBA | event_handler_offset), not (EVBA + event_handler_offset), so EVBA and exception
code segments must be set up appropriately. The same mechanisms are used to service all different types of events, including external interrupt requests, yielding a uniform event handling
scheme.
An interrupt controller does the priority handling of the external interrupts and provides the
autovector offset to the CPU.
4.5.1
System Stack Issues
Event handling in AVR32UC uses the system stack pointed to by the system stack pointer,
SP_SYS, for pushing and popping R8-R12, LR, status register, and return address. Since event
code may be timing-critical, SP_SYS should point to memory addresses in the IRAM section,
since the timing of accesses to this memory section is both fast and deterministic.
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The user must also make sure that the system stack is large enough so that any event is able to
push the required registers to stack. If the system stack is full, and an event occurs, the system
will enter an UNDEFINED state.
4.5.2
Exceptions and Interrupt Requests
When an event other than scall or debug request is received by the core, the following actions
are performed atomically:
1. The pending event will not be accepted if it is masked. The I3M, I2M, I1M, I0M, EM, and
GM bits in the Status Register are used to mask different events. Not all events can be
masked. A few critical events (NMI, Unrecoverable Exception, TLB Multiple Hit, and
Bus Error) can not be masked. When an event is accepted, hardware automatically
sets the mask bits corresponding to all sources with equal or lower priority. This inhibits
acceptance of other events of the same or lower priority, except for the critical events
listed above. Software may choose to clear some or all of these bits after saving the
necessary state if other priority schemes are desired. It is the event source’s responsability to ensure that their events are left pending until accepted by the CPU.
2. When a request is accepted, the Status Register and Program Counter of the current
context is stored to the system stack. If the event is an INT0, INT1, INT2, or INT3, registers R8-R12 and LR are also automatically stored to stack. Storing the Status
Register ensures that the core is returned to the previous execution mode when the
current event handling is completed. When exceptions occur, both the EM and GM bits
are set, and the application may manually enable nested exceptions if desired by clearing the appropriate bit. Each exception handler has a dedicated handler address, and
this address uniquely identifies the exception source.
3. The Mode bits are set to reflect the priority of the accepted event, and the correct register file bank is selected. The address of the event handler, as shown in Table 4-4, is
loaded into the Program Counter.
The execution of the event handler routine then continues from the effective address calculated.
The rete instruction signals the end of the event. When encountered, the Return Status Register
and Return Address Register are popped from the system stack and restored to the Status Register and Program Counter. If the rete instruction returns from INT0, INT1, INT2, or INT3,
registers R8-R12 and LR are also popped from the system stack. The restored Status Register
contains information allowing the core to resume operation in the previous execution mode. This
concludes the event handling.
4.5.3
Supervisor Calls
The AVR32 instruction set provides a supervisor mode call instruction. The scall instruction is
designed so that privileged routines can be called from any context. This facilitates sharing of
code between different execution modes. The scall mechanism is designed so that a minimal
execution cycle overhead is experienced when performing supervisor routine calls from timecritical event handlers.
The scall instruction behaves differently depending on which mode it is called from. The behaviour is detailed in the instruction set reference. In order to allow the scall routine to return to the
correct context, a return from supervisor call instruction, rets, is implemented. In the AVR32UC
CPU, scall and rets uses the system stack to store the return address and the status register.
4.5.4
Debug Requests
The AVR32 architecture defines a dedicated Debug mode. When a debug request is received by
the core, Debug mode is entered. Entry into Debug mode can be masked by the DM bit in the
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status register. Upon entry into Debug mode, hardware sets the SR[D] bit and jumps to the
Debug Exception handler. By default, Debug mode executes in the exception context, but with
dedicated Return Address Register and Return Status Register. These dedicated registers
remove the need for storing this data to the system stack, thereby improving debuggability. The
mode bits in the status register can freely be manipulated in Debug mode, to observe registers
in all contexts, while retaining full privileges.
Debug mode is exited by executing the retd instruction. This returns to the previous context.
4.5.5
Entry Points for Events
Several different event handler entry points exists. In AVR32UC, the reset address is
0x8000_0000. This places the reset address in the boot flash memory area.
TLB miss exceptions and scall have a dedicated space relative to EVBA where their event handler can be placed. This speeds up execution by removing the need for a jump instruction placed
at the program address jumped to by the event hardware. All other exceptions have a dedicated
event routine entry point located relative to EVBA. The handler routine address identifies the
exception source directly.
AVR32UC uses the ITLB and DTLB protection exceptions to signal a MPU protection violation.
ITLB and DTLB miss exceptions are used to signal that an access address did not map to any of
the entries in the MPU. TLB multiple hit exception indicates that an access address did map to
multiple TLB entries, signalling an error.
All external interrupt requests have entry points located at an offset relative to EVBA. This
autovector offset is specified by an external Interrupt Controller. The programmer must make
sure that none of the autovector offsets interfere with the placement of other code. The autovector offset has 14 address bits, giving an offset of maximum 16384 bytes.
Special considerations should be made when loading EVBA with a pointer. Due to security considerations, the event handlers should be located in non-writeable flash memory, or optionally in
a privileged memory protection region if an MPU is present.
If several events occur on the same instruction, they are handled in a prioritized way. The priority
ordering is presented in Table 4-4. If events occur on several instructions at different locations in
the pipeline, the events on the oldest instruction are always handled before any events on any
younger instruction, even if the younger instruction has events of higher priority than the oldest
instruction. An instruction B is younger than an instruction A if it was sent down the pipeline later
than A.
The addresses and priority of simultaneous events are shown in Table 4-4. Some of the exceptions are unused in AVR32UC since it has no MMU, coprocessor interface, or floating-point unit.
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Table 4-4.
Priority and Handler Addresses for Events
Priority
Handler Address
Name
Event source
Stored Return Address
1
0x8000_0000
Reset
External input
Undefined
2
Provided by OCD system
OCD Stop CPU
OCD system
First non-completed instruction
3
EVBA+0x00
Unrecoverable exception
Internal
PC of offending instruction
4
EVBA+0x04
TLB multiple hit
MPU
5
EVBA+0x08
Bus error data fetch
Data bus
First non-completed instruction
6
EVBA+0x0C
Bus error instruction fetch
Data bus
First non-completed instruction
7
EVBA+0x10
NMI
External input
First non-completed instruction
8
Autovectored
Interrupt 3 request
External input
First non-completed instruction
9
Autovectored
Interrupt 2 request
External input
First non-completed instruction
10
Autovectored
Interrupt 1 request
External input
First non-completed instruction
11
Autovectored
Interrupt 0 request
External input
First non-completed instruction
12
EVBA+0x14
Instruction Address
CPU
PC of offending instruction
13
EVBA+0x50
ITLB Miss
MPU
14
EVBA+0x18
ITLB Protection
MPU
PC of offending instruction
15
EVBA+0x1C
Breakpoint
OCD system
First non-completed instruction
16
EVBA+0x20
Illegal Opcode
Instruction
PC of offending instruction
17
EVBA+0x24
Unimplemented instruction
Instruction
PC of offending instruction
18
EVBA+0x28
Privilege violation
Instruction
PC of offending instruction
19
EVBA+0x2C
Floating-point
UNUSED
20
EVBA+0x30
Coprocessor absent
Instruction
PC of offending instruction
21
EVBA+0x100
Supervisor call
Instruction
PC(Supervisor Call) +2
22
EVBA+0x34
Data Address (Read)
CPU
PC of offending instruction
23
EVBA+0x38
Data Address (Write)
CPU
PC of offending instruction
24
EVBA+0x60
DTLB Miss (Read)
MPU
25
EVBA+0x70
DTLB Miss (Write)
MPU
26
EVBA+0x3C
DTLB Protection (Read)
MPU
PC of offending instruction
27
EVBA+0x40
DTLB Protection (Write)
MPU
PC of offending instruction
28
EVBA+0x44
DTLB Modified
UNUSED
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4.6
Module Configuration
All AT32UC3A3 parts implement the CPU and Architecture Revision 2.
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5. Memories
5.1
Embedded Memories
• Internal High-Speed Flash
– 256KBytes (AT32UC3A3256/S)
– 128Kbytes (AT32UC3A3128/S)
– 64Kbytes (AT32UC3A364/S)
• 0 wait state access at up to 36MHz in worst case conditions
• 1 wait state access at up to 66MHz in worst case conditions
• Pipelined Flash architecture, allowing burst reads from sequential Flash locations, hiding
penalty of 1 wait state access
• Pipelined Flash architecture typically reduces the cycle penalty of 1 wait state operation
to only 15% compared to 0 wait state operation
• 100 000 write cycles, 15-year data retention capability
• Sector lock capabilities, Bootloader protection, Security Bit
• 32 fuses, preserved during Chip Erase
• User page for data to be preserved during Chip Erase
• Internal High-Speed SRAM
– 64KBytes, Single-cycle access at full speed on CPU Local Bus and accessible through the
High Speed Bud (HSB) matrix
– 2x32KBytes, accessible independently through the High Speed Bud (HSB) matrix
5.2
Physical Memory Map
The System Bus is implemented as a bus matrix. All system bus addresses are fixed, and they
are never remapped in any way, not even in boot.
Note that AVR32 UC CPU uses unsegmented translation, as described in the AVR32UC Technical Architecture Manual.
The 32-bit physical address space is mapped as follows:
Table 5-1.
AT32UC3A3A4 Physical Memory Map
Size
Size
Size
AT32UC3A3256S
AT32UC3A3256
AT32UC3A4256S
AT32UC3A4256
AT32UC3A3128S
AT32UC3A3128
AT32UC3A4128S
AT32UC3A4128
AT32UC3A364S
AT32UC3A364
AT32UC3A464S
AT32UC3A464
Device
Start
Address
Embedded CPU SRAM
0x00000000
64KByte
64KByte
64KByte
Embedded Flash
0x80000000
256KByte
128KByte
64KByte
EBI SRAM CS0
0xC0000000
16MByte
16MByte
16MByte
EBI SRAM CS2
0xC8000000
16MByte
16MByte
16MByte
EBI SRAM CS3
0xCC000000
16MByte
16MByte
16MByte
EBI SRAM CS4
0xD8000000
16MByte
16MByte
16MByte
EBI SRAM CS5
0xDC000000
16MByte
16MByte
16MByte
EBI SRAM CS1
/SDRAM CS0
0xD0000000
128MByte
128MByte
128MByte
USB Data
0xE0000000
64KByte
64KByte
64KByte
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Table 5-1.
5.3
AT32UC3A3A4 Physical Memory Map
Size
Size
Size
Device
Start
Address
AT32UC3A3256S
AT32UC3A3256
AT32UC3A4256S
AT32UC3A4256
AT32UC3A3128S
AT32UC3A3128
AT32UC3A4128S
AT32UC3A4128
AT32UC3A364S
AT32UC3A364
AT32UC3A464S
AT32UC3A464
HRAMC0
0xFF000000
32KByte
32KByte
32KByte
HRAMC1
0xFF008000
32KByte
32KByte
32KByte
HSB-PB Bridge A
0xFFFF0000
64KByte
64KByte
64KByte
HSB-PB Bridge B
0xFFFE0000
64KByte
64KByte
64KByte
Peripheral Address Map
Table 5-2.
Peripheral Address Mapping
Address
Peripheral Name
0xFF100000
DMACA
DMA Controller - DMACA
0xFFFD0000
AES
Advanced Encryption Standard - AES
USB
USB 2.0 OTG Interface - USB
0xFFFE0000
0xFFFE1000
HMATRIX
HSB Matrix - HMATRIX
FLASHC
Flash Controller - FLASHC
0xFFFE1400
0xFFFE1C00
SMC
Static Memory Controller - SMC
0xFFFE2000
SDRAMC
SDRAM Controller - SDRAMC
ECCHRS
Error code corrector Hamming and Reed Solomon ECCHRS
BUSMON
Bus Monitor module - BUSMON
MCI
Mulitmedia Card Interface - MCI
MSI
Memory Stick Interface - MSI
0xFFFE2400
0xFFFE2800
0xFFFE4000
0xFFFE8000
0xFFFF0000
PDCA
Peripheral DMA Controller - PDCA
INTC
Interrupt controller - INTC
0xFFFF0800
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Table 5-2.
Peripheral Address Mapping
0xFFFF0C00
PM
Power Manager - PM
RTC
Real Time Counter - RTC
WDT
Watchdog Timer - WDT
EIC
External Interrupt Controller - EIC
0xFFFF0D00
0xFFFF0D30
0xFFFF0D80
0xFFFF1000
GPIO
0xFFFF1400
General Purpose Input/Output Controller - GPIO
USART0
Universal Synchronous/Asynchronous
Receiver/Transmitter - USART0
USART1
Universal Synchronous/Asynchronous
Receiver/Transmitter - USART1
USART2
Universal Synchronous/Asynchronous
Receiver/Transmitter - USART2
USART3
Universal Synchronous/Asynchronous
Receiver/Transmitter - USART3
0xFFFF1800
0xFFFF1C00
0xFFFF2000
0xFFFF2400
SPI0
Serial Peripheral Interface - SPI0
SPI1
Serial Peripheral Interface - SPI1
0xFFFF2800
0xFFFF2C00
TWIM0
Two-wire Master Interface - TWIM0
TWIM1
Two-wire Master Interface - TWIM1
0xFFFF3000
0xFFFF3400
SSC
Synchronous Serial Controller - SSC
TC0
Timer/Counter - TC0
ADC
Analog to Digital Converter - ADC
0xFFFF3800
0xFFFF3C00
0xFFFF4000
ABDAC
Audio Bitstream DAC - ABDAC
0xFFFF4400
TC1
Timer/Counter - TC1
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Table 5-2.
Peripheral Address Mapping
0xFFFF5000
TWIS0
Two-wire Slave Interface - TWIS0
TWIS1
Two-wire Slave Interface - TWIS1
0xFFFF5400
5.4
CPU Local Bus Mapping
Some of the registers in the GPIO module are mapped onto the CPU local bus, in addition to
being mapped on the Peripheral Bus. These registers can therefore be reached both by
accesses on the Peripheral Bus, and by accesses on the local bus.
Mapping these registers on the local bus allows cycle-deterministic toggling of GPIO pins since
the CPU and GPIO are the only modules connected to this bus. Also, since the local bus runs at
CPU speed, one write or read operation can be performed per clock cycle to the local busmapped GPIO registers.
The following GPIO registers are mapped on the local bus:
Table 5-3.
Local Bus Mapped GPIO Registers
Port
Register
Mode
Local Bus
Address
Access
0
Output Driver Enable Register (ODER)
WRITE
0x40000040
Write-only
SET
0x40000044
Write-only
CLEAR
0x40000048
Write-only
TOGGLE
0x4000004C
Write-only
WRITE
0x40000050
Write-only
SET
0x40000054
Write-only
CLEAR
0x40000058
Write-only
TOGGLE
0x4000005C
Write-only
Pin Value Register (PVR)
-
0x40000060
Read-only
Output Driver Enable Register (ODER)
WRITE
0x40000140
Write-only
SET
0x40000144
Write-only
CLEAR
0x40000148
Write-only
TOGGLE
0x4000014C
Write-only
WRITE
0x40000150
Write-only
SET
0x40000154
Write-only
CLEAR
0x40000158
Write-only
TOGGLE
0x4000015C
Write-only
-
0x40000160
Read-only
Output Value Register (OVR)
1
Output Value Register (OVR)
Pin Value Register (PVR)
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Table 5-3.
Local Bus Mapped GPIO Registers
Port
Register
Mode
Local Bus
Address
Access
2
Output Driver Enable Register (ODER)
WRITE
0x40000240
Write-only
SET
0x40000244
Write-only
CLEAR
0x40000248
Write-only
TOGGLE
0x4000024C
Write-only
WRITE
0x40000250
Write-only
SET
0x40000254
Write-only
CLEAR
0x40000258
Write-only
TOGGLE
0x4000025C
Write-only
Pin Value Register (PVR)
-
0x40000260
Read-only
Output Driver Enable Register (ODER)
WRITE
0x40000340
Write-only
SET
0x40000344
Write-only
CLEAR
0x40000348
Write-only
TOGGLE
0x4000034C
Write-only
WRITE
0x40000350
Write-only
SET
0x40000354
Write-only
CLEAR
0x40000358
Write-only
TOGGLE
0x4000035C
Write-only
-
0x40000360
Read-only
Output Value Register (OVR)
3
Output Value Register (OVR)
Pin Value Register (PVR)
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6. Boot Sequence
This chapter summarizes the boot sequence of the AT32UC3A3/A4. The behavior after powerup is controlled by the Power Manager. For specific details, refer to Section 7. ”Power Manager
(PM)” on page 40.
6.1
Starting of Clocks
After power-up, the device will be held in a reset state by the Power-On Reset circuitry, until the
power has stabilized throughout the device. Once the power has stabilized, the device will use
the internal RC Oscillator as clock source.
On system start-up, the PLLs are disabled. All clocks to all modules are running. No clocks have
a divided frequency, all parts of the system receives a clock with the same frequency as the
internal RC Oscillator.
6.2
Fetching of Initial Instructions
After reset has been released, the AVR32 UC CPU starts fetching instructions from the reset
address, which is 0x8000_0000. This address points to the first address in the internal Flash.
The code read from the internal Flash is free to configure the system to use for example the
PLLs, to divide the frequency of the clock routed to some of the peripherals, and to gate the
clocks to unused peripherals.
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7. Power Manager (PM)
Rev: 2.3.1.0
7.1
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
7.2
Controls integrated oscillators and PLLs
Generates clocks and resets for digital logic
Supports 2 crystal oscillators 0.4-20MHz
Supports 2 PLLs 40-240MHz
Supports 32KHz ultra-low power oscillator
Integrated low-power RC oscillator
On-the fly frequency change of CPU, HSB, PBA, and PBB clocks
Sleep modes allow simple disabling of logic clocks, PLLs, and oscillators
Module-level clock gating through maskable peripheral clocks
Wake-up from internal or external interrupts
Generic clocks with wide frequency range provided
Automatic identification of reset sources
Controls brownout detector (BOD and BOD33), RC oscillator, and bandgap voltage reference
through control and calibration registers
Overview
The Power Manager (PM) controls the oscillators and PLLs, and generates the clocks and
resets in the device. The PM controls two fast crystal oscillators, as well as two PLLs, which can
multiply the clock from either oscillator to provide higher frequencies. Additionally, a low-power
32KHz oscillator is used to generate the real-time counter clock for high accuracy real-time measurements. The PM also contains a low-power RC oscillator with fast start-up time, which can be
used to clock the digital logic.
The provided clocks are divided into synchronous and generic clocks. The synchronous clocks
are used to clock the main digital logic in the device, namely the CPU, and the modules and
peripherals connected to the HSB, PBA, and PBB buses. The generic clocks are asynchronous
clocks, which can be tuned precisely within a wide frequency range, which makes them suitable
for peripherals that require specific frequencies, such as timers and communication modules.
The PM also contains advanced power-saving features, allowing the user to optimize the power
consumption for an application. The synchronous clocks are divided into three clock domains,
one for the CPU and HSB, one for modules on the PBA bus, and one for modules on the PBB
bus.The three clocks can run at different speeds, so the user can save power by running peripherals at a relatively low clock, while maintaining a high CPU performance. Additionally, the
clocks can be independently changed on-the-fly, without halting any peripherals. This enables
the user to adjust the speed of the CPU and memories to the dynamic load of the application,
without disturbing or re-configuring active peripherals.
Each module also has a separate clock, enabling the user to switch off the clock for inactive
modules, to save further power. Additionally, clocks and oscillators can be automatically
switched off during idle periods by using the sleep instruction on the CPU. The system will return
to normal on occurrence of interrupts.
The Power Manager also contains a Reset Controller, which collects all possible reset sources,
generates hard and soft resets, and allows the reset source to be identified by software.
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7.3
Block Diagram
Figure 7-1.
Power Manager Block Diagram
RCSYS
Oscillator 0
Synchronous
Clock Generator
Synchronous
clocks
CPU, HSB,
PBA, PBB
Generic Clock
Generator
G eneric clocks
PLL0
PLL1
Oscillator 1
32 KHz
Oscillator
O SC/PLL
Control signals
CLK_32
RC
Oscillator
Slow clock
Oscillator and
PLL Control
Startup
Counter
Voltage Regulator
Interrupts
fuses
Sleep Controller
Sleep
instruction
Reset Controller
resets
Calibration
Registers
Brown-Out
Detector
Power-On
Detector
O ther reset
sources
External Reset Pad
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7.4
7.4.1
Product Dependencies
I/O Lines
The PM provides a number of generic clock outputs, which can be connected to output pins,
multiplexed with I/O lines. The programmer must first program the I/O controller to assign these
pins to their peripheral function. If the I/O pins of the PM are not used by the application, they
can be used for other purposes by the I/O controller.
7.4.2
Interrupt
The PM interrupt line is connected to one of the internal sources of the interrupt controller. Using
the PM interrupt requires the interrupt controller to be programmed first.
7.5
7.5.1
Functional Description
Slow Clock
The slow clock is generated from an internal RC oscillator which is always running, except in
Static mode. The slow clock can be used for the main clock in the device, as described in Section 7.5.5. The slow clock is also used for the Watchdog Timer and measuring various delays in
the Power Manager.
The RC oscillator has a 3 cycles startup time, and is always available when the CPU is running.
The RC oscillator operates at approximately 115 kHz. Software can change RC oscillator calibration through the use of the RCCR register. Please see the Electrical Characteristics section
for details.
RC oscillator can also be used as the RTC clock when crystal accuracy is not required.
7.5.2
Oscillator 0 and 1 Operation
The two main oscillators are designed to be used with an external crystal and two biasing capacitors, as shown in Figure 7-2 on page 43. Oscillator 0 can be used for the main clock in the
device, as described in Section 7.5.5. Both oscillators can be used as source for the generic
clocks, as described in Section 7.5.8.
The oscillators are disabled by default after reset. When the oscillators are disabled, the XIN and
XOUT pins can be used as general purpose I/Os. When the oscillators are configured to use an
external clock, the clock must be applied to the XIN pin while the XOUT pin can be used as a
general purpose I/O.
The oscillators can be enabled by writing to the OSCnEN bits in MCCTRL. Operation mode
(external clock or crystal) is chosen by writing to the MODE field in OSCCTRLn. Oscillators are
automatically switched off in certain sleep modes to reduce power consumption, as described in
Section 7.5.7.
After a hard reset, or when waking up from a sleep mode that disabled the oscillators, the oscillators may need a certain amount of time to stabilize on the correct frequency. This start-up time
can be set in the OSCCTRLn register.
The PM masks the oscillator outputs during the start-up time, to ensure that no unstable clocks
propagate to the digital logic. The OSCnRDY bits in POSCSR are automatically set and cleared
according to the status of the oscillators. A zero to one transition on these bits can also be configured to generate an interrupt, as described in Section 7.6.7.
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Figure 7-2.
Oscillator Connections
C2
XO UT
XIN
C1
7.5.3
32 KHz Oscillator Operation
The 32 KHz oscillator operates as described for Oscillator 0 and 1 above. The 32 KHz oscillator
is used as source clock for the Real-Time Counter.
The oscillator is disabled by default, but can be enabled by writing OSC32EN in OSCCTRL32.
The oscillator is an ultra-low power design and remains enabled in all sleep modes except Static
mode.
While the 32 KHz oscillator is disabled, the XIN32 and XOUT32 pins are available as general
purpose I/Os. When the oscillator is configured to work with an external clock (MODE field in
OSCCTRL32 register), the external clock must be connected to XIN32 while the XOUT32 pin
can be used as a general purpose I/O.
The startup time of the 32 KHz oscillator can be set in the OSCCTRL32, after which OSC32RDY
in POSCSR is set. An interrupt can be generated on a zero to one transition of OSC32RDY.
As a crystal oscillator usually requires a very long startup time (up to 1 second), the 32 KHz
oscillator will keep running across resets, except Power-On-Reset.
7.5.4
PLL Operation
The device contains two PLLs, PLL0 and PLL1. These are disabled by default, but can be
enabled to provide high frequency source clocks for synchronous or generic clocks. The PLLs
can take either Oscillator 0 or 1 as reference clock. The PLL output is divided by a multiplication
factor, and the PLL compares the resulting clock to the reference clock. The PLL will adjust its
output frequency until the two compared clocks are equal, thus locking the output frequency to a
multiple of the reference clock frequency.
When the PLL is switched on, or when changing the clock source or multiplication factor for the
PLL, the PLL is unlocked and the output frequency is undefined. The PLL clock for the digital
logic is automatically masked when the PLL is unlocked, to prevent connected digital logic from
receiving a too high frequency and thus become unstable.
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Figure 7-3.
PLL with Control Logic and Filters
PLLMUL
Output
Divider
Osc0 clock
Osc1 clock
0
Input
Divider
1
PLLOSC
7.5.4.1
Fin
PLLDIV
PLL
Mask
PLL clock
LOCK
PLLEN
PLLOPT
Enabling the PLL
PLLn is enabled by writing the PLLEN bit in the PLLn register. PLLOSC selects Oscillator 0 or 1
as clock source. The PLLMUL and PLLDIV bitfields must be written with the multiplication and
division factors, respectively, creating the voltage controlled ocillator frequency fVCO and the PLL
frequency fPLL :
if PLLDIV > 0
fIN = fOSC/2 • PLLDIV
fVCO = (PLLMUL+1)/(PLLDIV) • fOSC
if PLLDIV = 0
fIN = fOSC
fVCO = 2 • (PLLMUL+1) • fOSC
Note:
Refer to Electrical Characteristics section for FIN and FVCO frequency range.
If PLLOPT[1] field is set to 0:
fPLL = fVCO.
If PLLOPT[1] field is set to 1:
fPLL = fVCO / 2.
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The PLLn:PLLOPT field should be set to proper values according to the PLL operating frequency. The PLLOPT field can also be set to divide the output frequency of the PLLs by 2.
The lock signal for each PLL is available as a LOCKn flag in POSCSR. An interrupt can be generated on a 0 to 1 transition of these bits.
7.5.5
Synchronous Clocks
The slow clock (default), Oscillator 0, or PLL0 provide the source for the main clock, which is the
common root for the synchronous clocks for the CPU/HSB, PBA, and PBB modules. The main
clock is divided by an 8-bit prescaler, and each of these four synchronous clocks can run from
any tapping of this prescaler, or the undivided main clock, as long as fCPU ≥ fPBA,B,. The synchronous clock source can be changed on-the fly, responding to varying load in the application. The
clock domains can be shut down in sleep mode, as described in Section 7.5.7. Additionally, the
clocks for each module in the four domains can be individually masked, to avoid power consumption in inactive modules.
Figure 7-4.
Synchronous Clock Generation
Sleep
Controller
Sleep
instruction
0
Main clock
Slow clock
Osc0 clock
PLL0 clock
1
Prescaler
CPUDIV
MCSEL
7.5.5.1
Mask
CPU clocks
AHB clocks
CPUMASK
APBAclocks
APBB clocks
CPUSEL
Selecting PLL or oscillator for the main clock
The common main clock can be connected to the slow clock, Oscillator 0, or PLL0. By default,
the main clock will be connected to the slow clock. The user can connect the main clock to Oscillator 0 or PLL0 by writing the MCSEL field in the Main Clock Control Register (MCCTRL). This
must only be done after that unit has been enabled, otherwise a deadlock will occur. Care
should also be taken that the new frequency of the synchronous clocks does not exceed the
maximum frequency for each clock domain.
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7.5.5.2
Selecting synchronous clock division ratio
The main clock feeds an 8-bit prescaler, which can be used to generate the synchronous clocks.
By default, the synchronous clocks run on the undivided main clock. The user can select a prescaler division for the CPU clock by writing CKSEL.CPUDIV to 1 and CPUSEL to the prescaling
value, resulting in a CPU clock frequency:
f CPU = f main ⁄ 2
( CPUSEL + 1 )
Similarly, the clock for the PBA, and PBB can be divided by writing their respective fields. To
ensure correct operation, frequencies must be selected so that fCPU ≥ fPBA,B. Also, frequencies
must never exceed the specified maximum frequency for each clock domain.
CKSEL can be written without halting or disabling peripheral modules. Writing CKSEL allows a
new clock setting to be written to all synchronous clocks at the same time. It is possible to keep
one or more clocks unchanged by writing the same value a before to the xxxDIV and xxxSEL
fields. This way, it is possible to e.g. scale CPU and HSB speed according to the required performance, while keeping the PBA and PBB frequency constant.
For modules connected to the HSB bus, the PB clock frequency must be set to the same frequency than the CPU clock.
7.5.5.3
7.5.6
Clock ready flag
There is a slight delay from CKSEL is written and the new clock setting becomes effective. During this interval, the Clock Ready (CKRDY) flag in ISR will read as 0. If IER.CKRDY is written to
1, the Power Manager interrupt can be triggered when the new clock setting is effective. CKSEL
must not be re-written while CKRDY is 0, or the system may become unstable or hang.
Peripheral Clock Masking
By default, the clock for all modules are enabled, regardless of which modules are actually being
used. It is possible to disable the clock for a module in the CPU, HSB, PBA, or PBB clock
domain by writing the corresponding bit in the Clock Mask register (CPU/HSB/PBA/PBB) to 0.
When a module is not clocked, it will cease operation, and its registers cannot be read or written.
The module can be re-enabled later by writing the corresponding mask bit to 1.
A module may be connected to several clock domains, in which case it will have several mask
bits.
Table 7-7 on page 57 contains the list of implemented maskable clocks.
7.5.6.1
Cautionary note
The OCD clock must never be switched off if the user wishes to debug the device with a JTAG
debugger.
Note that clocks should only be switched off if it is certain that the module will not be used.
Switching off the clock for the internal RAM will cause a problem if the stack is mapped there.
Switching off the clock to the Power Manager (PM), which contains the mask registers, or the
corresponding PBx bridge, will make it impossible to write the mask registers again. In this case,
they can only be re-enabled by a system reset.
7.5.6.2
Mask ready flag
Due to synchronization in the clock generator, there is a slight delay from a mask register is written until the new mask setting goes into effect. When clearing mask bits, this delay can usually
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be ignored. However, when setting mask bits, the registers in the corresponding module must
not be written until the clock has actually be re-enabled. The status flag MSKRDY in ISR provides the required mask status information. When writing either mask register with any value,
this bit is cleared. The bit is set when the clocks have been enabled and disabled according to
the new mask setting. Optionally, the Power Manager interrupt can be enabled by writing the
MSKRDY bit in IER.
7.5.7
Sleep Modes
In normal operation, all clock domains are active, allowing software execution and peripheral
operation. When the CPU is idle, it is possible to switch off the CPU clock and optionally other
clock domains to save power. This is activated by the sleep instruction, which takes the sleep
mode index number as argument.
7.5.7.1
Entering and exiting sleep modes
The sleep instruction will halt the CPU and all modules belonging to the stopped clock domains.
The modules will be halted regardless of the bit settings of the mask registers.
Oscillators and PLLs can also be switched off to save power. Some of these modules have a relatively long start-up time, and are only switched off when very low power consumption is
required.
The CPU and affected modules are restarted when the sleep mode is exited. This occurs when
an interrupt triggers. Note that even if an interrupt is enabled in sleep mode, it may not trigger if
the source module is not clocked.
7.5.7.2
Supported sleep modes
The following sleep modes are supported. These are detailed in Table 7-1 on page 48.
• Idle: The CPU is stopped, the rest of the chip is operating. Wake-up sources are any
interrupt.
• Frozen: The CPU and HSB modules are stopped, peripherals are operating. Wake-up
sources are any interrupt from PB modules.
• Standby: All synchronous clocks are stopped, but oscillators and PLLs are running, allowing
quick wake-up to normal mode. Wake-up sources are RTC or external interrupt.
• Stop: As Standby, but Oscillator 0 and 1, and the PLLs are stopped. 32 KHz (if enabled) and
RC oscillators and RTC/WDT still operate. Wake-up sources are RTC, external interrupt, or
external reset pin.
• DeepStop: All synchronous clocks, Oscillator 0 and 1 and PLL 0 and 1 are stopped. 32 KHz
oscillator can run if enabled. RC oscillator still operates. Bandgap voltage reference, BOD
and BOD33 are turned off.
• Static: All oscillators, including 32 KHz and RC oscillator are stopped. Bandgap voltage
reference, BOD and BOD33 detectors areturned off.
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Table 7-1.
Sleep Modes
Osc0,1
PLL0,1,
SYSTIMER
Osc32
RCSYS
BOD &
BOD33 &
Bandgap
Voltage
Regulator
Index
Sleep Mode
CPU
HSB
PBA,B
GCLK
0
Idle
Stop
Run
Run
Run
Run
Run
On
Full power
1
Frozen
Stop
Stop
Run
Run
Run
Run
On
Full power
2
Standby
Stop
Stop
Stop
Run
Run
Run
On
Full power
3
Stop
Stop
Stop
Stop
Stop
Run
Run
On
Low power
4
DeepStop
Stop
Stop
Stop
Stop
Run
Run
Off
Low power
5
Static
Stop
Stop
Stop
Stop
Stop
Stop
Off
Low power
The power level of the internal voltage regulator is also adjusted according to the sleep mode to
reduce the internal regulator power consumption.
7.5.7.3
Precautions when entering sleep mode
Modules communicating with external circuits should normally be disabled before entering a
sleep mode that will stop the module operation. This prevents erratic behavior when entering or
exiting sleep mode. Please refer to the relevant module documentation for recommended
actions.
Communication between the synchronous clock domains is disturbed when entering and exiting
sleep modes. This means that bus transactions are not allowed between clock domains affected
by the sleep mode. The system may hang if the bus clocks are stopped in the middle of a bus
transaction.
The CPU is automatically stopped in a safe state to ensure that all CPU bus operations are complete when the sleep mode goes into effect. Thus, when entering Idle mode, no further action is
necessary.
When entering a sleep mode (except Idle mode), all HSB masters must be stopped before
entering the sleep mode. Also, if there is a chance that any PB write operations are incomplete,
the CPU should perform a read operation from any register on the PB bus before executing the
sleep instruction. This will stall the CPU while waiting for any pending PB operations to
complete.
7.5.7.4
Wake Up
The USB can be used to wake up the part from sleep modes through register AWEN of the
Power Manager.
7.5.8
Generic Clocks
Timers, communication modules, and other modules connected to external circuitry may require
specific clock frequencies to operate correctly. The Power Manager contains an implementation
defined number of generic clocks that can provide a wide range of accurate clock frequencies.
Each generic clock module runs from either Oscillator 0 or 1, or PLL0 or 1. The selected source
can optionally be divided by any even integer up to 256. Each clock can be independently
enabled and disabled, and is also automatically disabled along with peripheral clocks by the
Sleep Controller.
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Figure 7-5.
Generic Clock Generation
Sleep
Controller
0
Osc0 clock
Osc1 clock
PLL0 clock
PLL1 clock
Divider
Generic Clock
1
1
PLLSEL
OSCSEL
7.5.8.1
Mask
0
DIV
DIVEN
CEN
Enabling a generic clock
A generic clock is enabled by writing the CEN bit in GCCTRL to 1. Each generic clock can use
either Oscillator 0 or 1 or PLL0 or 1 as source, as selected by the PLLSEL and OSCSEL bits.
The source clock can optionally be divided by writing DIVEN to 1 and the division factor to DIV,
resulting in the output frequency:
f GCLK = f SRC ⁄ ( 2 × ( DIV + 1 ) )
7.5.8.2
Disabling a generic clock
The generic clock can be disabled by writing CEN to zero or entering a sleep mode that disables
the PB clocks. In either case, the generic clock will be switched off on the first falling edge after
the disabling event, to ensure that no glitches occur. If CEN is written to 0, the bit will still read as
1 until the next falling edge occurs, and the clock is actually switched off. When writing CEN to 0,
the other bits in GCCTRL should not be changed until CEN reads as 0, to avoid glitches on the
generic clock.
When the clock is disabled, both the prescaler and output are reset.
7.5.8.3
Changing clock frequency
When changing generic clock frequency by writing GCCTRL, the clock should be switched off by
the procedure above, before being re-enabled with the new clock source or division setting. This
prevents glitches during the transition.
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7.5.8.4
Generic clock implementation
The generic clocks are allocated to different functions as shown in Table 7-2 on page 50.
Table 7-2.
7.5.9
Generic Clock Allocation
Clock number
Function
0
GCLK0 pin
1
GCLK1 pin
2
GCLK2 pin
3
GCLK3 pin
4
GCLK_USBB
5
GCLK_ABDAC
Divided PB Clocks
The clock generator in the Power Manager provides divided PBA and PBB clocks for use by
peripherals that require a prescaled PBx clock. This is described in the documentation for the
relevant modules.
The divided clocks are not directly maskable, but are stopped in sleep modes where the PBx
clocks are stopped.
7.5.10
Debug Operation
The OCD clock must never be switched off if the user wishes to debug the device with a JTAG
debugger.
During a debug session, the user may need to halt the system to inspect memory and CPU registers. The clocks normally keep running during this debug operation, but some peripherals may
require the clocks to be stopped, e.g. to prevent timer overflow, which would cause the program
to fail. For this reason, peripherals on the PBA and PBB buses may use “debug qualified” PBx
clocks. This is described in the documentation for the relevant modules. The divided PBx clocks
are always debug qualified clocks.
Debug qualified PBx clocks are stopped during debug operation. The debug system can optionally keep these clocks running during the debug operation. This is described in the
documentation for the On-Chip Debug system.
7.5.11
Reset Controller
The Reset Controller collects the various reset sources in the system and generates hard and
soft resets for the digital logic.
The device contains a Power-On Detector, which keeps the system reset until power is stable.
This eliminates the need for external reset circuitry to guarantee stable operation when powering
up the device.
It is also possible to reset the device by asserting the RESET_N pin. This pin has an internal pullup, and does not need to be driven externally when negated. Table 7-4 on page 52 lists these
and other reset sources supported by the Reset Controller.
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Figure 7-6.
Reset Controller Block Diagram
RC_RCAUSE
R ESET_N
CPU, HSB,
PBA, PBB
P o w e r-O n
D e te c to r
R eset
C o n tro lle r
B ro w n o u t
D e te c to r
O C D , R T C /W D T ,
C lo c k G e n e ra to r
JTAG
OCD
WDT
In addition to the listed reset types, the JTAG can keep parts of the device statically reset
through the JTAG Reset Register. See JTAG documentation for details.
Table 7-3.
Reset Description
Reset source
Description
Power-on Reset
Supply voltage below the power-on reset detector
threshold voltage
External Reset
RESET_N pin asserted
Brownout Reset
Supply voltage below the brownout reset detector
threshold voltage
CPU Error
Caused by an illegal CPU access to external memory
while in Supervisor mode
Watchdog Timer
See watchdog timer documentation.
OCD
See On-Chip Debug documentation
When a reset occurs, some parts of the chip are not necessarily reset, depending on the reset
source. Only the Power On Reset (POR) will force a reset of the whole chip.
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Table 7-4 on page 52 lists parts of the device that are reset, depending on the reset source.
Table 7-4.
Effect of the Different Reset Events
Power-On
Reset
External
Reset
Watchdog
Reset
BOD
Reset
BOD33
Reset
CPU
Error
Reset
OCD
Reset
CPU/HSB/PBA/PBB
(excluding Power Manager)
Y
Y
Y
Y
Y
Y
Y
32 KHz oscillator
Y
N
N
N
N
N
N
RTC control register
Y
N
N
N
N
N
N
GPLP registers
Y
N
N
N
N
N
N
Watchdog control register
Y
Y
N
Y
Y
Y
Y
Voltage calibration register
Y
N
N
N
N
N
N
RCSYS Calibration register
Y
N
N
N
N
N
N
BOD control register
Y
Y
N
N
N
N
N
BOD33 control register
Y
Y
N
N
N
N
N
Bandgap control register
Y
Y
N
N
N
N
N
Clock control registers
Y
Y
Y
Y
Y
Y
Y
Osc0/Osc1 and control registers
Y
Y
Y
Y
Y
Y
Y
PLL0/PLL1 and control registers
Y
Y
Y
Y
Y
Y
Y
OCD system and OCD registers
Y
Y
N
Y
Y
Y
N
The cause of the last reset can be read from the RCAUSE register. This register contains one bit
for each reset source, and can be read during the boot sequence of an application to determine
the proper action to be taken.
7.5.11.1
Power-On detector
The Power-On Detector monitors the VDDCORE supply pin and generates a reset when the
device is powered on. The reset is active until the supply voltage from the linear regulator is
above the power-on threshold level. The reset will be re-activated if the voltage drops below the
power-on threshold level. See Electrical Characteristics for parametric details.
7.5.11.2
Brown-Out detector
The Brown-Out Detector (BOD) monitors the VDDCORE supply pin and compares the supply
voltage to the brown-out detection level, as set in BOD.LEVEL. The BOD is disabled by default,
but can be enabled either by software or by flash fuses. The Brown-Out Detector can either generate an interrupt or a reset when the supply voltage is below the brown-out detection level. In
any case, the BOD output is available in bit POSCSR.BODDET bit.
Note that any change to the BOD.LEVEL field of the BOD register should be done with the BOD
deactivated to avoid spurious reset or interrupt.
See Electrical Characteristics chapter for parametric details.
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7.5.11.3
Brown-Out detector 3V3
The Brown-Out Detector 3V3 (BOD33) monitors one VDDIO supply pin and compares the supply voltage to the brown-out detection 3V3 level, which is typically calibrated at 2V7. The BOD33
is enabled by default, but can be disabled by software. The Brown-Out Detector 3V3 can either
generate an interrupt or a reset when the supply voltage is below the brown-out detection3V3
level. In any case, the BOD33 output is available in bit POSCSR.BOD33DET bit.
Note that any change to the BOD33.LEVEL field of the BOD33 register should be done with the
BOD33 deactivated to avoid spurious reset or interrupt.
The BOD33.LEVEL default value is calibrated to 2V7
See Electrical Characteristics chapter for parametric details.
Table 7-5.
7.5.11.4
7.5.12
VDDIO pin monitored by BOD33
TFBGA144
QFP144
VFBGA100
H5
81
E5
External reset
The external reset detector monitors the state of the RESET_N pin. By default, a low level on
this pin will generate a reset.
Calibration Registers
The Power Manager controls the calibration of the RC oscillator, voltage regulator, bandgap
voltage reference through several calibrations registers.
Those calibration registers are loaded after a Power On Reset with default values stored in factory-programmed flash fuses.
Although it is not recommended to override default factory settings, it is still possible to override
these default values by writing to those registers. To prevent unexpected writes due to software
bugs, write access to these registers is protected by a “key”. First, a write to the register must be
made with the field “KEY” equal to 0x55 then a second write must be issued with the “KEY” field
equal to 0xAA.
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7.6
User Interface
Table 7-6.
PM Register Memory Map
Offset
Register
Register Name
Access
Reset State
0x000
Main Clock Control
MCCTRL
Read/Write
0x00000000
0x0004
Clock Select
CKSEL
Read/Write
0x00000000
0x008
CPU Mask
CPUMASK
Read/Write
0x00000003
0x00C
HSB Mask
HSBMASK
Read/Write
0x00000FFF
0x010
PBA Mask
PBAMASK
Read/Write
0x001FFFFF
0x014
PBB Mask
PBBMASK
Read/Write
0x000003FF
0x020
PLL0 Control
PLL0
Read/Write
0x00000000
0x024
PLL1 Control
PLL1
Read/Write
0x00000000
0x028
Oscillator 0 Control Register
OSCCTRL0
Read/Write
0x00000000
0x02C
Oscillator 1 Control Register
OSCCTRL1
Read/Write
0x00000000
0x030
Oscillator 32 Control Register
OSCCTRL32
Read/Write
0x00000000
0x040
PM Interrupt Enable Register
IER
Write-only
0x00000000
0x044
PM Interrupt Disable Register
IDR
Write-only
0x00000000
0x048
PM Interrupt Mask Register
IMR
Read-only
0x00000000
0x04C
PM Interrupt Status Register
ISR
Read-only
0x00000000
00050
PM Interrupt Clear Register
ICR
Write-only
0x00000000
0x054
Power and Oscillators Status Register
POSCSR
Read/Write
0x00000000
0x060
Generic Clock Control 0
GCCTRL0
Read/Write
0x00000000
0x064
Generic Clock Control 1
GCCTRL1
Read/Write
0x00000000
0x068
Generic Clock Control 2
GCCTRL2
Read/Write
0x00000000
0x06C
Generic Clock Control 3
GCCTRL3
Read/Write
0x00000000
0x070
Generic Clock Control 4
GCCTRL4
Read/Write
0x00000000
0x0C0
RC Oscillator Calibration Register
RCCR
Read/Write
Factory settings
0x0C4
Bandgap Calibration Register
BGCR
Read/Write
Factory settings
0x0C8
Linear Regulator Calibration Register
VREGCR
Read/Write
Factory settings
0x0D0
BOD Level Register
BOD
Read/Write
BOD fuses in Flash
0x0D4
BOD33 Level Register
BOD33
Read/Write
0x0140
Reset Cause Register
RCAUSE
Read/Write
Latest Reset Source
0x0144
Asynchronous Wake Enable Register
AWEN
Read/Write
0x00000000
0x200
General Purpose Low-Power register
GPLP
Read/Write
0x00000000
BOD33 reset enable
BOD33 LEVEL=2V7
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7.6.1
Name:
Main Clock Control Register
MCCTRL
Access Type:
Read/Write
Offset:
0x00
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
OSC1EN
OSC0EN
MCSEL
• OSC1EN: Oscillator 1 Enable
1: Oscillator 1 is enabled
0: Oscillator 1 is disabled
• OSC0EN: Oscillator 0 Enable
1: Oscillator 0 is enabled
0: Oscillator 0 is disabled
• MCSEL: Main Clock Select
This field contains the clock selected as the main clock.
MCSEL
Selected Clock
0b00
Slow Clock
0b01
Oscillator 0
0b10
PLL 0
0b11
Reserved
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7.6.2
Name:
Clock Select Register
CKSEL
Access Type:
Read/Write
Offset:
0x04
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
PBBDIV
-
-
-
-
23
22
21
20
19
PBADIV
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
CPUDIV
-
-
-
-
PBBSEL
18
17
16
PBASEL
CPUSEL
• PBBDIV: PBB Division Enable
PBBDIV = 0: PBB clock equals main clock.
PBBDIV = 1: PBB clock equals main clock divided by 2(PBBSEL+1).
• PBADIV, PBASEL: PBA Division and Clock Select
PBADIV = 0: PBA clock equals main clock.
PBADIV = 1: PBA clock equals main clock divided by 2(PBASEL+1).
• CPUDIV, CPUSEL: CPU/HSB Division and Clock Select
CPUDIV = 0: CPU/HSB clock equals main clock.
CPUDIV = 1: CPU/HSB clock equals main clock divided by 2(CPUSEL+1).
Note that if xxxDIV is written to 0, xxxSEL should also be written to 0 to ensure correct operation.
Also note that writing this register clears POSCSR.CKRDY. The register must not be re-written until CKRDY goes high.
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7.6.3
Name:
Clock Mask Registers
CPU/HSB/PBA/PBBMASK
Access Type:
Read/Write
Offset:
0x08-0x14
Reset Value:
0x00000003/0x00000FFF/0x001FFFFF/0x000003FF
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
MASK[31:24]
23
22
21
20
MASK[23:16]
15
14
13
12
MASK[15:8]
7
6
5
4
MASK[7:0]
• MASK: Clock Mask
If bit n is cleared, the clock for module n is stopped. If bit n is set, the clock for module n is enabled according to the current
power mode. The number of implemented bits in each mask register, as well as which module clock is controlled by each bit, is
shown in Table 7-7 on page 57.
Table 7-7.
Maskable module clocks in AT32UC3A3.
Bit
CPUMASK
HSBMASK
PBAMASK
PBBMASK
0
-
FLASHC
INTC
HMATRIX
1
OCD(1)
PBA Bridge
I/O
USBB
2
-
PBB Bridge
PDCA
FLASHC
3
-
USBB
PM/RTC/EIC
SMC
4
-
PDCA
ADC
SDRAMC
5
-
EBI
SPI0
ECCHRS
6
-
PBC Bridge
SPI1
MCI
7
-
DMACA
TWIM0
BUSMON
8
-
BUSMON
TWIM1
MSI
9
-
HRAMC0
TWIS0
AES
10
-
HRAMC1
TWIS1
-
11
-
(2)
USART0
-
12
-
-
USART1
-
13
-
-
USART2
-
14
-
-
USART3
-
15
-
-
SSC
-
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Table 7-7.
Maskable module clocks in AT32UC3A3.
Bit
CPUMASK
HSBMASK
PBAMASK
PBBMASK
16
SYSTIMER
(compare/count
registers clk)
-
TC0
-
17
-
-
TC1
-
18
-
-
ABDAC
-
-
(2)
-
19
-
20
-
-
(2)
31:
21
-
-
-
Note:
1. This bit must be set to one if the user wishes to debug the device with a JTAG debugger.
2. This bits must be set to one
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7.6.4
Name:
PLL Control Registers
PLL0,1
Access Type:
Read/Write
Offset:
0x20-0x24
Reset Value:
0x00000000
31
30
29
28
PLLTEST
-
23
22
21
20
-
-
-
-
15
14
13
12
-
-
-
-
7
6
5
4
-
-
-
27
26
25
24
18
17
16
9
8
1
0
PLLOSC
PLLEN
PLLCOUNT
19
PLLMUL
11
10
PLLDIV
3
PLLOPT
2
• PLLTEST: PLL Test
Reserved for internal use. Always write to 0.
• PLLCOUNT: PLL Count
Specifies the number of slow clock cycles before ISR.LOCKn will be set after PLLn has been written, or after PLLn has been
automatically re-enabled after exiting a sleep mode.
• PLLMUL: PLL Multiply Factor
• PLLDIV: PLL Division Factor
These fields determine the ratio of the PLL output frequency to the source oscillator frequency. Formula is detallied in ”Enabling
the PLL” on page 44
• PLLOPT: PLL Option
Select the operating range for the PLL.
PLLOPT[0]: Select the VCO frequency range
PLLOPT[1]: Enable the extra output divider
PLLOPT[2]: Disable the Wide-Bandwidth mode (Wide-Bandwidth mode allows a faster startup time and out-of-lock time)
Description
PLLOPT[0]: VCO frequency
0
160MHz<fvco<240MHz
1
80MHz<fvco<180MHz
PLLOPT[1]: Output divider
0
fPLL = fvco
1
fPLL = fvco/2
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Description
PLLOPT[2]
0
Wide Bandwidth Mode enabled
1
Wide Bandwidth Mode disabled
• PLLOSC: PLL Oscillator Select
0: Oscillator 0 is the source for the PLL.
1: Oscillator 1 is the source for the PLL.
• PLLEN: PLL Enable
0: PLL is disabled.
1: PLL is enabled.
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7.6.5
Name:
Oscillator 0/1 Control Registers
OSCCTRL0,1
Access Type:
Read/Write
Offset:
0x28-0x2C
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
7
6
5
4
3
-
-
-
-
-
STARTUP
2
1
0
MODE
• STARTUP: Oscillator Startup Time
Select startup time for the oscillator.
STARTUP
Number of RC oscillator
clock cycle
Approximative Equivalent time
(RCSYS = 115 kHz)
0
0
0
1
64
560 us
2
128
1.1 ms
3
2048
18 ms
4
4096
36 ms
5
8192
71 ms
6
16384
142 ms
7
Reserved
Reserved
• MODE: Oscillator Mode
Choose between crystal, or external clock
0: External clock connected on XIN, XOUT can be used as an I/O (no crystal)
1 to 3: reserved
4: Crystal is connected to XIN/XOUT - Oscillator is used with gain G0 ( XIN from 0.4
5: Crystal is connected to XIN/XOUT - Oscillator is used with gain G1 ( XIN from 0.9
6: Crystal is connected to XIN/XOUT - Oscillator is used with gain G2 ( XIN from 3.0
7: Crystal is connected to XIN/XOUT - Oscillator is used with gain G3 ( XIN from 8.0
MHz to 0.9 MHz ).
MHz to 3.0 MHz ).
MHz to 8.0 MHz ).
Mhz).
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7.6.6
Name:
32 KHz Oscillator Control Register
OSCCTRL32
Access Type:
Read/Write
Offset:
0x30
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
15
14
13
12
11
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
OSC32EN
STARTUP
10
9
8
MODE
• STARTUP: Oscillator Startup Time
Select startup time for 32 KHz oscillator
STARTUP
Number of RC oscillator
clock cycle
Approximative Equivalent time
(RCSYS = 115 kHz)
0
0
0
1
128
1.1 ms
2
8192
72.3 ms
3
16384
143 ms
4
65536
570 ms
5
131072
1.1 s
6
262144
2.3 s
7
524288
4.6 s
Note: This register is only reset by Power-On Reset
• MODE: Oscillator Mode
Choose between crystal, or external clock
0: External clock connected on XIN32, XOUT32 can be used as a I/O (no crystal)
1: Crystal is connected to XIN32/XOUT32 - Oscillator is used with automatic gain control
2 to 7: Reserved
• OSC32EN: Enable the 32 KHz oscillator
0: 32 KHz Oscillator is disabled
1: 32 KHz Oscillator is enabled
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7.6.7
Name:
Interrupt Enable Register
IER
Access Type:
Write-only
Offset:
0x40
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
BOD33DET
BODDET
15
14
13
12
11
10
9
8
-
-
-
-
-
-
OSC32RDY
OSC1RDY
7
6
5
4
3
2
1
0
OSC0RDY
MSKRDY
CKRDY
-
-
-
LOCK1
LOCK0
Writing a one to a bit in this register will set the corresponding bit in IMR.
Writing a zero to a bit in this register has no effect.
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7.6.8
Name:
Interrupt Disable Register
IDR
Access Type:
Write-only
Offset:
0x44
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
BOD33DET
BODDET
15
14
13
12
11
10
9
8
-
-
-
-
-
-
OSC32RDY
OSC1RDY
7
6
5
4
3
2
1
0
OSC0RDY
MSKRDY
CKRDY
-
-
-
LOCK1
LOCK0
Writing a one to a bit in this register will clear the corresponding bit in IMR.
Writing a zero to a bit in this register has no effect.
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7.6.9
Name:
Interrupt Mask Register
IMR
Access Type:
Read-only
Offset:
0x48
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
BOD33DET
BODDET
15
14
13
12
11
10
9
8
-
-
-
-
-
-
OSC32RDY
OSC1RDY
7
6
5
4
3
2
1
0
OSC0RDY
MSKRDY
CKRDY
-
-
-
LOCK1
LOCK0
0: The corresponding interrupt is disabled.
1: The corresponding interrupt is enabled.
A bit in this register is cleared when the corresponding bit in IDR is written to one.
A bit in this register is set when the corresponding bit in IER is written to one.
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7.6.10
Name:
Interrupt Status Register
ISR
Access Type:
Read-only
Offset:
0x4C
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
BOD33DET
BODDET
15
14
13
12
11
10
9
8
-
-
-
-
-
-
OSC32RDY
OSC1RDY
7
6
5
4
3
2
1
0
OSC0RDY
MSKRDY
CKRDY
-
-
-
LOCK1
LOCK0
• BOD33DET: Brown out detection
This bit is set when a 0 to 1 transition on POSCSR.BOD33DET bit is detected: BOD33 has detected that power supply is
going below BOD33 reference value.
This bit is cleared when the corresponding bit in ICR is written to one.
• BODDET: Brown out detection
This bit is set when a 0 to 1 transition on POSCSR.BODDET bit is detected: BOD has detected that power supply is going
below BOD reference value.
This bit is cleared when the corresponding bit in ICR is written to one.
• OSC32RDY: 32 KHz oscillator Ready
This bit is set when a 0 to 1 transition on the POSCSR.OSC32RDY bit is detected: The 32 KHz oscillator is stable and
ready to be used as clock source.
This bit is cleared when the corresponding bit in ICR is written to one.
• OSC1RDY: Oscillator 1 Ready
This bit is set when a 0 to 1 transition on the POSCSR.OSC1RDY bit is detected: Oscillator 1 is stable and ready to be used
as clock source.
This bit is cleared when the corresponding bit in ICR is written to one.
• OSC0RDY: Oscillator 0 Ready
This bit is set when a 0 to 1 transition on the POSCSR.OSC1RDY bit is detected: Oscillator 1 is stable and ready to be used
as clock source.
This bit is cleared when the corresponding bit in ICR is written to one.
• MSKRDY: Mask Ready
This bit is set when a 0 to 1 transition on the POSCSR.MSKRDY bit is detected: Clocks are now masked according to the
(CPU/HSB/PBA/PBB)_MASK registers.
This bit is cleared when the corresponding bit in ICR is written to one.
• CKRDY: Clock Ready
0: The CKSEL register has been written, and the new clock setting is not yet effective.
1: The synchronous clocks have frequencies as indicated in the CKSEL register.
Note: Writing a one to ICR.CKRDY has no effect.
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• LOCK1: PLL1 locked
This bit is set when a 0 to 1 transition on the POSCSR.LOCK1 bit is detected: PLL 1 is locked and ready to be selected as
clock source.
This bit is cleared when the corresponding bit in ICR is written to one.
• LOCK0: PLL0 locked
This bit is set when a 0 to 1 transition on the POSCSR.LOCK0 bit is detected: PLL 0 is locked and ready to be selected as
clock source.
This bit is cleared when the corresponding bit in ICR is written to one.
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7.6.11
Name:
Interrupt Clear Register
ICR
Access Type:
Write-only
Offset:
0x50
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
BOD33DET
BODDET
15
14
13
12
11
10
9
8
-
-
-
-
-
-
OSC32RDY
OSC1RDY
7
6
5
4
3
2
1
0
OSC0RDY
MSKRDY
CKRDY
-
-
-
LOCK1
LOCK0
Writing a zero to a bit in this register has no effect.
Writing a one to a bit in this register will clear the corresponding bit in ISR and the corresponding interrupt request.
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7.6.12
Name:
Power and Oscillators Status Register
POSCSR
Access Type:
Read-only
Offset:
0x54
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
BOD33DET
BODDET
15
14
13
12
11
10
9
8
-
-
-
-
-
-
OSC32RDY
OSC1RDY
7
6
5
4
3
2
1
0
OSC0RDY
MSKRDY
CKRDY
-
-
-
LOCK1
LOCK0
• BOD33DET: Brown out 3V3 detection
0: No BOD33 event
1: BOD33 has detected that power supply is going below BOD33 reference value.
• BODDET: Brown out detection
0: No BOD event
1: BOD has detected that power supply is going below BOD reference value.
• OSC32RDY: 32 KHz oscillator Ready
0: The 32 KHz oscillator is not enabled or not ready.
1: The 32 KHz oscillator is stable and ready to be used as clock source.
• OSC1RDY: OSC1 ready
0: Oscillator 1 not enabled or not ready.
1: Oscillator 1 is stable and ready to be used as clock source.
• OSC0RDY: OSC0 ready
0: Oscillator 0 not enabled or not ready.
1: Oscillator 0 is stable and ready to be used as clock source.
• MSKRDY: Mask ready
0: Mask register has been changed, masking in progress.
1: Clock are masked according to xxx_MASK
• CKRDY:
0: The CKSEL register has been written, and the new clock setting is not yet effective.
1: The synchronous clocks have frequencies as indicated in the CKSEL register.
• LOCK1: PLL 1 locked
0:PLL 1 is unlocked
1:PLL 1 is locked, and ready to be selected as clock source.
• LOCK0: PLL 0 locked
0: PLL 0 is unlocked
1: PLL 0 is locked, and ready to be selected as clock source.
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7.6.13
Name:
Generic Clock Control Register
GCCTRLx
Access Type:
Read/Write
Offset:
0x60
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
DIV[7:0]
7
6
5
4
3
2
1
0
-
-
-
DIVEN
-
CEN
PLLSEL
OSCSEL
There is one GCCTRL register per generic clock in the design.
• DIV: Division Factor
• DIVEN: Divide Enable
0: The generic clock equals the undivided source clock.
1: The generic clock equals the source clock divided by 2*(DIV+1).
• CEN: Clock Enable
0: Clock is stopped.
1: Clock is running.
• PLLSEL: PLL Select
0: Oscillator is source for the generic clock.
1: PLL is source for the generic clock.
• OSCSEL: Oscillator Select
0: Oscillator (or PLL) 0 is source for the generic clock.
1: Oscillator (or PLL) 1 is source for the generic clock.
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7.6.14
Name:
Reset Cause Register
RCAUSE
Access Type:
Read-only
Offset:
0x140
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
BOD33
JTAGHARD
OCDRST
7
6
5
4
3
2
1
0
CPUERR
-
-
JTAG
WDT
EXT
BOD
POR
• BOD33: Brown-out 3V3 Reset
The CPU was reset due to the supply voltage 3V3 being lower than the brown-out threshold level.
• JTAGHARD: JTAG Hard Reset
The chip was reset by setting the bit RC_OCD in the JTAG reset register or by using the JTAG HALT instruction.
• OCDRST: OCD Reset
The CPU was reset because the RES strobe in the OCD Development Control register has been written to one.
• CPUERR: CPU Error
The CPU was reset because it had detected an illegal access.
• JTAG: JTAG reset
The CPU was reset by setting the bit RC_CPU in the JTAG reset register.
• WDT: Watchdog Reset
The CPU was reset because of a watchdog timeout.
• EXT: External Reset Pin
The CPU was reset due to the RESET pin being asserted.
• BOD: Brown-out Reset
The CPU was reset due to the supply voltage 1V8 being lower than the brown-out threshold level.
• POR Power-on Reset
The CPU was reset due to the supply voltage being lower than the power-on threshold level.
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7.6.15
Asynchronous Wake Up Enable
Name:
AWEN
Access Type:
Read/Write
Offset:
0x144
Reset Value:
-
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
USB_WAKEN
• USB_WAKEN : Wake Up Enable Register
Writing a zero to this bit will disable the USB wake up.
Writing a one to this bit will enable the USB wake up.
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7.6.16
Name:
BOD Control Register
BOD
Access Type:
Read/Write
Offset:
0xD0
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
KEY
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
FCD
15
14
13
12
11
10
9
8
-
-
-
-
-
-
7
6
5
4
3
2
-
HYST
CTRL
1
0
LEVEL
• KEY: Register Write protection
This field must be written twice, first with key value 0x55, then 0xAA, for a write operation to have an effect.
• FCD: BOD Fuse calibration done
Set to 1 when CTRL, HYST and LEVEL fields has been updated by the Flash fuses after power-on reset or Flash fuses update
If one, the CTRL, HYST and LEVEL values will not be updated again by Flash fuses
Can be cleared to allow subsequent overwriting of the value by Flash fuses
• CTRL: BOD Control
0: BOD is off
1: BOD is enabled and can reset the chip
2: BOD is enabled and but cannot reset the chip. Only interrupt will be sent to interrupt controller, if enabled in the IMR register.
3: BOD is off
• HYST: BOD Hysteresis
0: No hysteresis
1: Hysteresis On
• LEVEL: BOD Level
This field sets the triggering threshold of the BOD. See Electrical Characteristics for actual voltage levels.
Note that any change to the LEVEL field of the BOD register should be done with the BOD deactivated to avoid spurious reset
or interrupt.
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7.6.17
Name:
BOD33 Control Register
BOD33
Access Type:
Read/Write
Offset:
0xD4
Reset Value:
0x0000010X
31
30
29
28
27
26
25
24
KEY
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
FCD
15
14
13
12
11
10
9
8
-
-
-
-
-
-
7
6
5
4
3
2
-
-
CTRL
1
0
LEVEL
• KEY: Register Write protection
This field must be written twice, first with key value 0x55, then 0xAA, for a write operation to have an effect.
• FCD: BOD33 Fuse calibration done
Set to 1 when LEVEL field has been updated by the Flash fuses after power-on reset or Flash fuses update
If one, the LEVEL value will not be updated again by Flash fuses
Can be cleared to allow subsequent overwriting of the value by Flash fuses
• CTRL: BOD33 Control
0: BOD33 is off
1: BOD33 is enabled and can reset the chip
2: BOD33 is enabled and but cannot reset the chip. Only interrupt will be sent to interrupt controller, if enabled in the IMR
register.
3: BOD33 is off
• LEVEL: BOD33 Level
This field sets the triggering threshold of the BOD33. See Electrical Characteristics for actual voltage levels.
Note that any change to the LEVEL field of the BOD33 register should be done with the BOD33 deactivated to avoid spurious
reset or interrupt.
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7.6.18
Name:
RC Oscillator Calibration Register
RCCR
Access Type:
Read/Write
Offset:
0xC0
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
KEY
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
FCD
15
14
13
12
11
10
9
8
-
-
-
-
-
-
7
6
5
4
3
2
CALIB
1
0
CALIB
• KEY: Register Write protection
This field must be written twice, first with key value 0x55, then 0xAA, for a write operation to have an effect.
• FCD: Flash Calibration Done
Set to 1 when CTRL, HYST, and LEVEL fields have been updated by the Flash fuses after power-on reset, or after Flash fuses
are reprogrammed. The CTRL, HYST and LEVEL values will not be updated again by the Flash fuses until a new power-on
reset or the FCD field is written to zero.
• CALIB: Calibration Value
Calibration Value for the RC oscillator.
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7.6.19
Name:
Bandgap Calibration Register
BGCR
Access Type:
Read/Write
Offset:
0xC4
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
KEY
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
FCD
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
CALIB
• KEY: Register Write protection
This field must be written twice, first with key value 0x55, then 0xAA, for a write operation to have an effect.
• FCD: Flash Calibration Done
Set to 1 when the CALIB field has been updated by the Flash fuses after power-on reset or when the Flash fuses are
reprogrammed. The CALIB field will not be updated again by the Flash fuses until a new power-on reset or the FCD field is
written to zero.
• CALIB: Calibration value
Calibration value for Bandgap. See Electrical Characteristics for voltage values.
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7.6.20
Name:
PM Voltage Regulator Calibration Register
VREGCR
Access Type:
Read/Write
Offset:
0xC8
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
KEY
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
FCD
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
CALIB
• KEY: Register Write protection
This field must be written twice, first with key value 0x55, then 0xAA, for a write operation to have an effect.
Calibration value for Voltage Regulator. See Electrical Characteristics for voltage values.
• FCD: Flash Calibration Done
Set to 1 when the CALIB field has been updated by the Flash fuses after power-on reset or when the Flash fuses are
reprogrammed. The CALIB field will not be updated again by the Flash fuses until a new power-on reset or the FCD field is
written to zero.
• CALIB: Calibration value
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7.6.21
Name:
General Purpose Low-power Register
GPLP
Access Type:
Read/Write
Offset:
0x200
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
GPLP
23
22
21
20
GPLP
15
14
13
12
GPLP
7
6
5
4
GPLP
These registers are general purpose 32-bit registers that are reset only by power-on-reset. Any other reset will keep the content
of these registers untouched.
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8. Real Time Counter (RTC)
Rev: 2.4.0.1
8.1
Features
• 32-bit real-time counter with 16-bit prescaler
• Clocked from RC oscillator or 32KHz oscillator
• Long delays
•
•
•
•
8.2
– Max timeout 272years
High resolution: Max count frequency 16KHz
Extremely low power consumption
Available in all sleep modes except Static
Interrupt on wrap
Overview
The Real Time Counter (RTC) enables periodic interrupts at long intervals, or accurate measurement of real-time sequences. The RTC is fed from a 16-bit prescaler, which is clocked from
the system RC oscillator or the 32KHz crystal oscillator. Any tapping of the prescaler can be
selected as clock source for the RTC, enabling both high resolution and long timeouts. The prescaler cannot be written directly, but can be cleared by the user.
The RTC can generate an interrupt when the counter wraps around the value stored in the top
register (TOP), producing accurate periodic interrupts.
8.3
Block Diagram
Figure 8-1.
Real Time Counter Block Diagram
CTRL
CLK32
CLK_32
EN PSEL
1
16-bit Prescaler
RCSYS
TOP
32-bit counter
TOPI
IRQ
0
VAL
8.4
Product Dependencies
In order to use this module, other parts of the system must be configured correctly, as described
below.
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8.4.1
Power Management
The RTC remains operating in all sleep modes except Static mode. Interrupts are not available
in DeepStop mode.
8.4.2
Clocks
The RTC can use the system RC oscillator as clock source. This oscillator is always enabled
whenever this module is active. Please refer to the Electrical Characteristics chapter for the
characteristic frequency of this oscillator (fRC).
The RTC can also use the 32 KHz crystal oscillator as clock source. This oscillator must be
enabled before use. Please refer to the Power Manager chapter for details.
The clock for the RTC bus interface (CLK_RTC) is generated by the Power Manager. This clock
is enabled at reset, and can be disabled in the Power Manager. It is recommended to disable the
RTC before disabling the clock, to avoid freezing the RTC in an undefined state.
8.4.3
Interrupts
The RTC interrupt request line is connected to the interrupt controller. Using the RTC interrupt
requires the interrupt controller to be programmed first.
8.4.4
8.5
8.5.1
8.5.1.1
Debug Operation
The RTC prescaler is frozen during debug operation, unless the OCD system keeps peripherals
running in debug operation.
Functional Description
RTC Operation
Source clock
The RTC is enabled by writing a one to the Enable bit in the Control Register (CTRL.EN). The
16-bit prescaler will then increment on the selected clock. The prescaler cannot be read or written, but it can be reset by writing a one to the Prescaler Clear bit in CTRL register (CTRL.PCLR).
The 32KHz Oscillator Select bit in CTRL register (CTRL.CLK32) selects either the RC oscillator
or the 32 KHz oscillator as clock source (defined as INPUT in the formula below) for the
prescaler.
The Prescale Select field in CTRL register (CTRL.PSEL) selects the prescaler tapping, selecting
the source clock for the RTC:
f RTC = f INPUT ⁄ 2
8.5.1.2
( PSEL + 1 )
Counter operation
When enabled, the RTC will increment until it reaches TOP, and then wraps to 0x0. The status
bit TOPI in Interrupt Status Register (ISR) is set to one when this occurs. From 0x0 the counter
will count TOP+1 cycles of the source clock before it wraps back to 0x0.
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The RTC count value can be read from or written to the Value register (VAL). Due to synchronization, continuous reading of the VAL register with the lowest prescaler setting will skip every
other value.
8.5.1.3
RTC interrupt
The RTC interrupt is enabled by writing a one to the Top Interrupt bit in the Interrupt Enable Register (IER.TOPI), and is disabled by writing a one to the Top Interrupt bit in the Interrupt Disable
Register (IDR.TOPI). The Interrupt Mask Register (IMR) can be read to see whether or not the
interrupt is enabled. If enabled, an interrupt will be generated if the TOPI bit in the Interrupt Status Register (ISR) is set. The TOPI bit in ISR can be cleared by writing a one to the TOPI bit in
the Interrupt Clear Register (ICR.TOPI).
The RTC interrupt can wake the CPU from all sleep modes except DeepStop and Static modes.
8.5.1.4
RTC wakeup
The RTC can also wake up the CPU directly without triggering an interrupt when the ISR.TOPI
bit is set. In this case, the CPU will continue executing from the instruction following the sleep
instruction.
This direct RTC wake-up is enabled by writing a one to the Wake Enable bit in the CTRL register
(CTRL.WAKEN). When the CPU wakes from sleep, the CTRL.WAKEN bit must be written to
zero to clear the internal wake signal to the sleep controller, otherwise a new sleep instruction
will have no effect.
The RTC wakeup is available in all sleep modes except Static mode. The RTC wakeup can be
configured independently of the RTC interrupt.
8.5.1.5
Busy bit
Due to the crossing of clock domains, the RTC uses a few clock cycles to propagate the values
stored in CTRL, TOP, and VAL to the RTC. The RTC Busy bit in CTRL (CTRL.BUSY) indicates
that a register write is still going on and all writes to TOP, CTRL, and VAL will be discarded until
the CTRL.BUSY bit goes low again.
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8.6
User Interface
Table 8-1.
RTC Register Memory Map
Offset
Register
Register Name
Access
Reset
0x00
Control Register
CTRL
Read/Write
0x00000000
0x04
Value Register
VAL
Read/Write
0x00000000
0x08
Top Register
TOP
Read/Write
0x00000000
0x10
Interrupt Enable Register
IER
Write-only
0x00000000
0x14
Interrupt Disable Register
IDR
Write-only
0x00000000
0x18
Interrupt Mask Register
IMR
Read-only
0x00000000
0x1C
Interrupt Status Register
ISR
Read-only
0x00000000
0x20
Interrupt Clear Register
ICR
Write-only
0x00000000
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8.6.1
Name:
Control Register
CTRL
Access Type:
Read/Write
Offset:
0x00
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
CLKEN
15
14
13
12
11
10
9
8
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
BUSY
CLK32
WAKEN
PCLR
EN
PSEL
• CLKEN: Clock Enable
1: The clock is enabled.
0: The clock is disabled.
• PSEL: Prescale Select
Selects prescaler bit PSEL as source clock for the RTC.
• BUSY: RTC Busy
This bit is set when the RTC is busy and will discard writes to TOP, VAL, and CTRL.
This bit is cleared when the RTC accepts writes to TOP, VAL, and CTRL.
• CLK32: 32 KHz Oscillator Select
1: The RTC uses the 32 KHz oscillator as clock source.
0: The RTC uses the RC oscillator as clock source.
• WAKEN: Wakeup Enable
1: The RTC wakes up the CPU from sleep modes.
0: The RTC does not wake up the CPU from sleep modes.
• PCLR: Prescaler Clear
Writing a one to this bit clears the prescaler.
Writing a zero to this bit has no effect.
This bit always reads as zero.
• EN: Enable
1: The RTC is enabled.
0: The RTC is disabled.
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8.6.2
Name:
Value Register
VAL
Access Type:
Read/Write
Offset:
0x04
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
VAL[31:24]
23
22
21
20
VAL[23:16]
15
14
13
12
VAL[15:8]
7
6
5
4
VAL[7:0]
• VAL[31:0]: RTC Value
This value is incremented on every rising edge of the source clock.
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8.6.3
Name:
Top Register
TOP
Access Type:
Read/Write
Offset:
0x08
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
VAL[31:24]
23
22
21
20
VAL[23:16]
15
14
13
12
VAL[15:8]
7
6
5
4
VAL[7:0]
• VAL[31:0]: RTC Top Value
VAL wraps at this value.
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8.6.4
Name:
Interrupt Enable Register
IER
Access Type:
Write-only
Offset:
0x10
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
TOPI
Writing a zero to a bit in this register has no effect.
Writing a one to a bit in this register will set the corresponding bit in IMR.
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8.6.5
Name:
Interrupt Disable Register
IDR
Access Type:
Write-only
Offset:
0x14
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
TOPI
Writing a zero to a bit in this register has no effect.
Writing a one to a bit in this register will clear the corresponding bit in IMR.
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8.6.6
Name:
Interrupt Mask Register
IMR
Access Type:
Read-only
Offset:
0x18
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
TOPI
0: The corresponding interrupt is disabled.
1: The corresponding interrupt is enabled.
A bit in this register is cleared when the corresponding bit in IDR is written to one.
A bit in this register is set when the corresponding bit in IER is written to one.
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8.6.7
Name:
Interrupt Status Register
ISR
Access Type:
Read-only
Offset:
0x1C
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
TOPI
• TOPI: Top Interrupt
This bit is set when VAL has wrapped at its top value.
This bit is cleared when the corresponding bit in ICR is written to one.
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8.6.8
Name:
Interrupt Clear Register
ICR
Access Type:
Write-only
Offset:
0x20
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
TOPI
Writing a zero to a bit in this register has no effect.
Writing a one to a bit in this register will clear the corresponding bit in SR and the corresponding interrupt request.
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9. Watchdog Timer (WDT)
Rev: 2.4.0.1
9.1
Features
• Watchdog timer counter with 32-bit prescaler
• Clocked from the system RC oscillator (RCSYS)
9.2
Overview
The Watchdog Timer (WDT) has a prescaler generating a time-out period. This prescaler is
clocked from the RC oscillator. The watchdog timer must be periodically reset by software within
the time-out period, otherwise, the device is reset and starts executing from the boot vector. This
allows the device to recover from a condition that has caused the system to be unstable.
9.3
Block Diagram
Figure 9-1.
WDT Block Diagram
CLR
RCSYS
32-bit
Prescaler
EN
9.4
Watchdog
Detector
Watchdog Reset
CTRL
Product Dependencies
In order to use this module, other parts of the system must be configured correctly, as described
below.
9.4.1
Power Management
When the WDT is enabled, the WDT remains clocked in all sleep modes, and it is not possible to
enter Static mode.
9.4.2
Clocks
The WDT can use the system RC oscillator (RCSYS) as clock source. This oscillator is always
enabled whenever these modules are active. Please refer to the Electrical Characteristics chapter for the characteristic frequency of this oscillator (fRC).
9.4.3
Debug Operation
The WDT prescaler is frozen during debug operation, unless the On-Chip Debug (OCD) system
keeps peripherals running in debug operation.
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9.5
Functional Description
The WDT is enabled by writing a one to the Enable bit in the Control register (CTRL.EN). This
also enables the system RC clock (CLK_RCSYS) for the prescaler. The Prescale Select field
(PSEL) in the CTRL register selects the watchdog time-out period:
TWDT = 2(PSEL+1) / fRC
The next time-out period will begin as soon as the watchdog reset has occurred and count down
during the reset sequence. Care must be taken when selecting the PSEL field value so that the
time-out period is greater than the startup time of the chip, otherwise a watchdog reset can reset
the chip before any code has been run.
To avoid accidental disabling of the watchdog, the CTRL register must be written twice, first with
the KEY field set to 0x55, then 0xAA without changing the other bits. Failure to do so will cause
the write operation to be ignored, and the CTRL register value will not change.
The Clear register (CLR) must be written with any value with regular intervals shorter than the
watchdog time-out period. Otherwise, the device will receive a soft reset, and the code will start
executing from the boot vector.
When the WDT is enabled, it is not possible to enter Static mode. Attempting to do so will result
in entering Shutdown mode, leaving the WDT operational.
9.6
User Interface
Table 9-1.
WDT Register Memory Map
Offset
Register
Register Name
Access
Reset
0x00
Control Register
CTRL
Read/Write
0x00000000
0x04
Clear Register
CLR
Write-only
0x00000000
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9.6.1
Name:
Control Register
CTRL
Access Type:
Read/Write
Offset:
0x00
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
KEY
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
EN
PSEL
• KEY: Write protection key
This field must be written twice, first with key value 0x55, then 0xAA, for a write operation to be effective.
This field always reads as zero.
• PSEL: Prescale Select
PSEL is used as watchdog timeout period.
• EN: WDT Enable
1: WDT is enabled.
0: WDT is disabled.
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9.6.2
Name:
Clear Register
CLR
Access Type:
Write-only
Offset:
0x04
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
CLR[31:24]
23
22
21
20
CLR[23:16]
15
14
13
12
CLR[15:8]
7
6
5
4
CLR[7:0]
• CLR:
Writing periodically any value to this field when the WDT is enabled, within the watchdog time-out period, will prevent a
watchdog reset.
This field always reads as zero.
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10. Interrupt Controller (INTC)
Rev: 1.0.1.5
10.1
Features
• Autovectored low latency interrupt service with programmable priority
– 4 priority levels for regular, maskable interrupts
– One Non-Maskable Interrupt
• Up to 64 groups of interrupts with up to 32 interrupt requests in each group
10.2
Overview
The INTC collects interrupt requests from the peripherals, prioritizes them, and delivers an interrupt request and an autovector to the CPU. The AVR32 architecture supports 4 priority levels for
regular, maskable interrupts, and a Non-Maskable Interrupt (NMI).
The INTC supports up to 64 groups of interrupts. Each group can have up to 32 interrupt request
lines, these lines are connected to the peripherals. Each group has an Interrupt Priority Register
(IPR) and an Interrupt Request Register (IRR). The IPRs are used to assign a priority level and
an autovector to each group, and the IRRs are used to identify the active interrupt request within
each group. If a group has only one interrupt request line, an active interrupt group uniquely
identifies the active interrupt request line, and the corresponding IRR is not needed. The INTC
also provides one Interrupt Cause Register (ICR) per priority level. These registers identify the
group that has a pending interrupt of the corresponding priority level. If several groups have a
pending interrupt of the same level, the group with the lowest number takes priority.
10.3
Block Diagram
Figure 10-1 gives an overview of the INTC. The grey boxes represent registers that can be
accessed via the user interface. The interrupt requests from the peripherals (IREQn) and the
NMI are input on the left side of the figure. Signals to and from the CPU are on the right side of
the figure.
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Figure 10-1. INTC Block Diagram
Interrupt Controller
CPU
NMIREQ
Masks
OR
IRRn
GrpReqN
IREQ63
IREQ34
IREQ33
IREQ32
OR
GrpReq1
INT_level,
offset
IPRn
.
.
.
Request
Masking ValReq1
INT_level,
offset
IPR1
.
.
.
INTLEVEL
Prioritizer
.
.
.
ValReqN
SREG
Masks
I[3-0]M
GM
AUTOVECTOR
IRR1
IREQ31
IREQ2
IREQ1
IREQ0
OR
GrpReq0
ValReq0
IPR0
INT_level,
offset
IRR0
IRR Registers
10.4
IPR Registers
ICR Registers
Product Dependencies
In order to use this module, other parts of the system must be configured correctly, as described
below.
10.4.1
Power Management
If the CPU enters a sleep mode that disables CLK_SYNC, the INTC will stop functioning and
resume operation after the system wakes up from sleep mode.
10.4.2
Clocks
The clock for the INTC bus interface (CLK_INTC) is generated by the Power Manager. This
clock is enabled at reset, and can be disabled in the Power Manager.
The INTC sampling logic runs on a clock which is stopped in any of the sleep modes where the
system RC oscillator is not running. This clock is referred to as CLK_SYNC. This clock is
enabled at reset, and only turned off in sleep modes where the system RC oscillator is stopped.
10.4.3
10.5
Debug Operation
When an external debugger forces the CPU into debug mode, the INTC continues normal
operation.
Functional Description
All of the incoming interrupt requests (IREQs) are sampled into the corresponding Interrupt
Request Register (IRR). The IRRs must be accessed to identify which IREQ within a group that
is active. If several IREQs within the same group are active, the interrupt service routine must
prioritize between them. All of the input lines in each group are logically ORed together to form
the GrpReqN lines, indicating if there is a pending interrupt in the corresponding group.
The Request Masking hardware maps each of the GrpReq lines to a priority level from INT0 to
INT3 by associating each group with the Interrupt Level (INTLEVEL) field in the corresponding
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Interrupt Priority Register (IPR). The GrpReq inputs are then masked by the mask bits from the
CPU status register. Any interrupt group that has a pending interrupt of a priority level that is not
masked by the CPU status register, gets its corresponding ValReq line asserted.
Masking of the interrupt requests is done based on five interrupt mask bits of the CPU status
register, namely Interrupt Level 3 Mask (I3M) to Interrupt Level 0 Mask (I0M), and Global Interrupt Mask (GM). An interrupt request is masked if either the GM or the corresponding interrupt
level mask bit is set.
The Prioritizer hardware uses the ValReq lines and the INTLEVEL field in the IPRs to select the
pending interrupt of the highest priority. If an NMI interrupt request is pending, it automatically
gets the highest priority of any pending interrupt. If several interrupt groups of the highest pending interrupt level have pending interrupts, the interrupt group with the lowest number is
selected.
The INTLEVEL and handler autovector offset (AUTOVECTOR) of the selected interrupt are
transmitted to the CPU for interrupt handling and context switching. The CPU does not need to
know which interrupt is requesting handling, but only the level and the offset of the handler
address. The IRR registers contain the interrupt request lines of the groups and can be read via
user interface registers for checking which interrupts of the group are actually active.
The delay through the INTC from the peripheral interrupt request is set until the interrupt request
to the CPU is set is three cycles of CLK_SYNC.
10.5.1
Non-Maskable Interrupts
A NMI request has priority over all other interrupt requests. NMI has a dedicated exception vector address defined by the AVR32 architecture, so AUTOVECTOR is undefined when
INTLEVEL indicates that an NMI is pending.
10.5.2
CPU Response
When the CPU receives an interrupt request it checks if any other exceptions are pending. If no
exceptions of higher priority are pending, interrupt handling is initiated. When initiating interrupt
handling, the corresponding interrupt mask bit is set automatically for this and lower levels in status register. E.g, if an interrupt of level 3 is approved for handling, the interrupt mask bits I3M,
I2M, I1M, and I0M are set in status register. If an interrupt of level 1 is approved, the masking
bits I1M and I0M are set in status register. The handler address is calculated by logical OR of
the AUTOVECTOR to the CPU system register Exception Vector Base Address (EVBA). The
CPU will then jump to the calculated address and start executing the interrupt handler.
Setting the interrupt mask bits prevents the interrupts from the same and lower levels to be
passed through the interrupt controller. Setting of the same level mask bit prevents also multiple
requests of the same interrupt to happen.
It is the responsibility of the handler software to clear the interrupt request that caused the interrupt before returning from the interrupt handler. If the conditions that caused the interrupt are not
cleared, the interrupt request remains active.
10.5.3
Clearing an Interrupt Request
Clearing of the interrupt request is done by writing to registers in the corresponding peripheral
module, which then clears the corresponding NMIREQ/IREQ signal.
The recommended way of clearing an interrupt request is a store operation to the controlling
peripheral register, followed by a dummy load operation from the same register. This causes a
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pipeline stall, which prevents the interrupt from accidentally re-triggering in case the handler is
exited and the interrupt mask is cleared before the interrupt request is cleared.
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10.6
User Interface
Table 10-1.
INTC Register Memory Map
Offset
Register
Register Name
Access
Reset
0x000
Interrupt Priority Register 0
IPR0
Read/Write
0x00000000
0x004
Interrupt Priority Register 1
IPR1
Read/Write
0x00000000
...
...
...
...
...
0x0FC
Interrupt Priority Register 63
IPR63
Read/Write
0x00000000
0x100
Interrupt Request Register 0
IRR0
Read-only
N/A
0x104
Interrupt Request Register 1
IRR1
Read-only
N/A
...
...
...
...
...
0x1FC
Interrupt Request Register 63
IRR63
Read-only
N/A
0x200
Interrupt Cause Register 3
ICR3
Read-only
N/A
0x204
Interrupt Cause Register 2
ICR2
Read-only
N/A
0x208
Interrupt Cause Register 1
ICR1
Read-only
N/A
0x20C
Interrupt Cause Register 0
ICR0
Read-only
N/A
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10.6.1
Interrupt Priority Registers
Register Name:
IPR0...IPR63
Access Type:
Read/Write
Offset:
0x000 - 0x0FC
Reset Value:
0x00000000
31
30
INTLEVEL[1:0]
29
-
28
-
27
-
26
-
25
-
24
-
23
-
22
-
21
-
20
-
19
-
18
-
17
-
16
-
15
-
14
-
13
12
9
8
7
6
5
4
3
AUTOVECTOR[7:0]
1
0
11
10
AUTOVECTOR[13:8]
2
• INTLEVEL: Interrupt Level
Indicates the EVBA-relative offset of the interrupt handler of the corresponding group:
00: INT0: Lowest priority
01: INT1
10: INT2
11: INT3: Highest priority
• AUTOVECTOR: Autovector Address
Handler offset is used to give the address of the interrupt handler. The least significant bit should be written to zero to give
halfword alignment.
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10.6.2
Name:
Interrupt Request Registers
IRR0...IRR63
Access Type:
Read-only
Offset:
0x0FF - 0x1FC
Reset Value:
N/A
31
IRR[32*x+31]
30
IRR[32*x+30]
29
IRR[32*x+29]
28
IRR[32*x+28]
27
IRR[32*x+27]
26
IRR[32*x+26]
25
IRR[32*x+25]
24
IRR[32*x+24]
23
IRR[32*x+23]
22
IRR[32*x+22]
21
IRR[32*x+21]
20
IRR[32*x+20]
19
IRR[32*x+19]
18
IRR[32*x+18]
17
IRR[32*x+17]
16
IRR[32*x+16]
15
IRR[32*x+15]
14
IRR[32*x+14]
13
IRR[32*x+13]
12
IRR[32*x+12]
11
IRR[32*x+11]
10
IRR[32*x+10]
9
IRR[32*x+9]
8
IRR[32*x+8]
7
IRR[32*x+7]
6
IRR[32*x+6]
5
IRR[32*x+5]
4
IRR[32*x+4]
3
IRR[32*x+3]
2
IRR[32*x+2]
1
IRR[32*x+1]
0
IRR[32*x+0]
• IRR: Interrupt Request line
This bit is cleared when no interrupt request is pending on this input request line.
This bit is set when an interrupt request is pending on this input request line.
The are 64 IRRs, one for each group. Each IRR has 32 bits, one for each possible interrupt request, for a total of 2048 possible
input lines. The IRRs are read by the software interrupt handler in order to determine which interrupt request is pending. The
IRRs are sampled continuously, and are read-only.
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10.6.3
Interrupt Cause Registers
Register Name:
ICR0...ICR3
Access Type:
Read-only
Offset:
0x200 - 0x20C
Reset Value:
N/A
31
-
30
-
29
-
28
-
27
-
26
-
25
-
24
-
23
-
22
-
21
-
20
-
19
-
18
-
17
-
16
-
15
-
14
-
13
-
12
-
11
-
10
-
9
-
8
-
7
-
6
-
5
4
3
2
1
0
CAUSE
• CAUSE: Interrupt Group Causing Interrupt of Priority n
ICRn identifies the group with the highest priority that has a pending interrupt of level n. This value is only defined when at least
one interrupt of level n is pending.
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10.7
Interrupt Request Signal Map
The various modules may output Interrupt request signals. These signals are routed to the Interrupt Controller (INTC), described in a later chapter. The Interrupt Controller supports up to 64
groups of interrupt requests. Each group can have up to 32 interrupt request signals. All interrupt
signals in the same group share the same autovector address and priority level. Refer to the
documentation for the individual submodules for a description of the semantics of the different
interrupt requests.
The interrupt request signals are connected to the INTC as follows.
Table 10-2.
Interrupt Request Signal Map
Group
Line
Module
Signal
0
0
CPU with optional MPU and optional OCD
0
External Interrupt Controller
EIC 0
1
External Interrupt Controller
EIC 1
2
External Interrupt Controller
EIC 2
3
External Interrupt Controller
EIC 3
4
External Interrupt Controller
EIC 4
5
External Interrupt Controller
EIC 5
6
External Interrupt Controller
EIC 6
7
External Interrupt Controller
EIC 7
8
Real Time Counter
RTC
9
Power Manager
PM
0
General Purpose Input/Output Controller
GPIO 0
1
General Purpose Input/Output Controller
GPIO 1
2
General Purpose Input/Output Controller
GPIO 2
3
General Purpose Input/Output Controller
GPIO 3
4
General Purpose Input/Output Controller
GPIO 4
5
General Purpose Input/Output Controller
GPIO 5
6
General Purpose Input/Output Controller
GPIO 6
7
General Purpose Input/Output Controller
GPIO 7
8
General Purpose Input/Output Controller
GPIO 8
9
General Purpose Input/Output Controller
GPIO 9
10
General Purpose Input/Output Controller
GPIO 10
11
General Purpose Input/Output Controller
GPIO 11
12
General Purpose Input/Output Controller
GPIO 12
13
General Purpose Input/Output Controller
GPIO 13
SYSREG
COMPARE
1
2
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Table 10-2.
Interrupt Request Signal Map
0
Peripheral DMA Controller
PDCA 0
1
Peripheral DMA Controller
PDCA 1
2
Peripheral DMA Controller
PDCA 2
3
Peripheral DMA Controller
PDCA 3
4
Peripheral DMA Controller
PDCA 4
5
Peripheral DMA Controller
PDCA 5
6
Peripheral DMA Controller
PDCA 6
7
Peripheral DMA Controller
PDCA 7
4
0
Flash Controller
FLASHC
5
0
Universal Synchronous/Asynchronous
Receiver/Transmitter
USART0
6
0
Universal Synchronous/Asynchronous
Receiver/Transmitter
USART1
7
0
Universal Synchronous/Asynchronous
Receiver/Transmitter
USART2
8
0
Universal Synchronous/Asynchronous
Receiver/Transmitter
USART3
9
0
Serial Peripheral Interface
SPI0
10
0
Serial Peripheral Interface
SPI1
11
0
Two-wire Master Interface
TWIM0
12
0
Two-wire Master Interface
TWIM1
13
0
Synchronous Serial Controller
SSC
0
Timer/Counter
TC00
1
Timer/Counter
TC01
2
Timer/Counter
TC02
0
Analog to Digital Converter
ADC
0
Timer/Counter
TC10
1
Timer/Counter
TC11
2
Timer/Counter
TC12
17
0
USB 2.0 OTG Interface
USBB
18
0
SDRAM Controller
19
0
Audio Bitstream DAC
20
0
Mulitmedia Card Interface
MCI
21
0
Advanced Encryption Standard
AES
3
14
15
16
SDRAMC
ABDAC
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Table 10-2.
Interrupt Request Signal Map
0
DMA Controller
DMACA BLOCK
1
DMA Controller
DMACA DSTT
2
DMA Controller
DMACA ERR
3
DMA Controller
DMACA SRCT
4
DMA Controller
DMACA TFR
26
0
Memory Stick Interface
MSI
27
0
Two-wire Slave Interface
TWIS0
28
0
Two-wire Slave Interface
TWIS1
29
0
Error code corrector Hamming and Reed
Solomon
22
ECCHRS
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11. External Interrupt Controller (EIC)
Rev: 2.4.0.0
11.1
Features
•
•
•
•
•
•
•
•
11.2
Dedicated interrupt request for each interrupt
Individually maskable interrupts
Interrupt on rising or falling edge
Interrupt on high or low level
Asynchronous interrupts for sleep modes without clock
Filtering of interrupt lines
Maskable NMI interrupt
Keypad scan support
Overview
The External Interrupt Controller (EIC) allows pins to be configured as external interrupts. Each
external interrupt has its own interrupt request and can be individually masked. Each external
interrupt can generate an interrupt on rising or falling edge, or high or low level. Every interrupt
input has a configurable filter to remove spikes from the interrupt source. Every interrupt pin can
also be configured to be asynchronous in order to wake up the part from sleep modes where the
CLK_SYNC clock has been disabled.
A Non-Maskable Interrupt (NMI) is also supported. This has the same properties as the other
external interrupts, but is connected to the NMI request of the CPU, enabling it to interrupt any
other interrupt mode.
The EIC can wake up the part from sleep modes without triggering an interrupt. In this mode,
code execution starts from the instruction following the sleep instruction.
The External Interrupt Controller has support for keypad scanning for keypads laid out in rows
and columns. Columns are driven by a separate set of scanning outputs, while rows are sensed
by the external interrupt lines. The pressed key will trigger an interrupt, which can be identified
through the user registers of the module.
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11.3
Block Diagram
Figure 11-1. EIC Block Diagram
EN
D IS
E n a b le
LEVEL
MODE
EDGE
ASYNC
P o la r it y
c o n tro l
A s y n c h ro n u s
d e te c to r
F IL T E R
LEVEL
MODE
EDGE
F ilt e r
E d g e /L e v e l
D e te c to r
E X T IN T n
NMI
CTRL
IC R
CTRL
IE R
ID R
IN T n
M ask
IS R
IM R
W ake
d e te c t
CLK_SYNC
IR Q n
E IC _ W A K E
C LK_R C SYS
P r e s c a le r
S h if t e r
PRESC
SCANm
P IN
EN
SCAN
11.4
I/O Lines Description
Table 11-1.
11.5
I/O Lines Description
Pin Name
Pin Description
Type
NMI
Non-Maskable Interrupt
Input
EXTINTn
External Interrupt
Input
SCANm
Keypad scan pin m
Output
Product Dependencies
In order to use this module, other parts of the system must be configured correctly, as described
below.
11.5.1
I/O Lines
The external interrupt pins (EXTINTn and NMI) are multiplexed with I/O lines. To generate an
external interrupt from an external source the source pin must be configured as an input pins by
the I/O Controller. It is also possible to trigger the interrupt by driving these pins from registers in
the I/O Controller, or another peripheral output connected to the same pin.
11.5.2
Power Management
All interrupts are available in all sleep modes as long as the EIC module is powered. However, in
sleep modes where CLK_SYNC is stopped, the interrupt must be configured to asynchronous
mode.
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11.5.3
Clocks
The clock for the EIC bus interface (CLK_EIC) is generated by the Power Manager. This clock is
enabled at reset, and can be disabled in the Power Manager.
The filter and synchronous edge/level detector runs on a clock which is stopped in any of the
sleep modes where the system RC oscillator is not running. This clock is referred to as
CLK_SYNC. Refer to the Module Configuration section at the end of this chapter for details.
The Keypad scan function operates on the system RC oscillator clock CLK_RCSYS.
11.5.4
Interrupts
The external interrupt request lines are connected to the interrupt controller. Using the external
interrupts requires the interrupt controller to be programmed first.
Using the Non-Maskable Interrupt does not require the interrupt controller to be programmed.
11.5.5
Debug Operation
The EIC is frozen during debug operation, unless the OCD system keeps peripherals running
during debug operation.
11.6
11.6.1
Functional Description
External Interrupts
The external interrupts are not enabled by default, allowing the proper interrupt vectors to be set
up by the CPU before the interrupts are enabled.
Each external interrupt INTn can be configured to produce an interrupt on rising or falling edge,
or high or low level. External interrupts are configured by the MODE, EDGE, and LEVEL registers. Each interrupt n has a bit INTn in each of these registers. Writing a zero to the INTn bit in
the MODE register enables edge triggered interrupts, while writing a one to the bit enables level
triggered interrupts.
If INTn is configured as an edge triggered interrupt, writing a zero to the INTn bit in the EDGE
register will cause the interrupt to be triggered on a falling edge on EXTINTn, while writing a one
to the bit will cause the interrupt to be triggered on a rising edge on EXTINTn.
If INTn is configured as a level triggered interrupt, writing a zero to the INTn bit in the LEVEL
register will cause the interrupt to be triggered on a low level on EXTINTn, while writing a one to
the bit will cause the interrupt to be triggered on a high level on EXTINTn.
Each interrupt has a corresponding bit in each of the interrupt control and status registers. Writing a one to the INTn bit in the Interrupt Enable Register (IER) enables the external interrupt
from pin EXTINTn to propagate from the EIC to the interrupt controller, while writing a one to
INTn bit in the Interrupt Disable Register (IDR) disables this propagation. The Interrupt Mask
Register (IMR) can be read to check which interrupts are enabled. When an interrupt triggers,
the corresponding bit in the Interrupt Status Register (ISR) will be set. This bit remains set until a
one is written to the corresponding bit in the Interrupt Clear Register (ICR) or the interrupt is
disabled.
Writing a one to the INTn bit in the Enable Register (EN) enables the external interrupt on pin
EXTINTn, while writing a one to INTn bit in the Disable Register (DIS) disables the external interrupt. The Control Register (CTRL) can be read to check which interrupts are enabled. If a bit in
the CTRL register is set, but the corresponding bit in IMR is not set, an interrupt will not propa-
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gate to the interrupt controller. However, the corresponding bit in ISR will be set, and
EIC_WAKE will be set.
If the CTRL.INTn bit is zero, then the corresponding bit in ISR will always be zero. Disabling an
external interrupt by writing to the DIS.INTn bit will clear the corresponding bit in ISR.
11.6.2
Synchronization and Filtering of External Interrupts
In synchronous mode the pin value of the EXTINTn pin is synchronized to CLK_SYNC, so
spikes shorter than one CLK_SYNC cycle are not guaranteed to produce an interrupt. The synchronization of the EXTINTn to CLK_SYNC will delay the propagation of the interrupt to the
interrupt controller by two cycles of CLK_SYNC, see Figure 11-2 on page 109 and Figure 11-3
on page 109 for examples (FILTER off).
It is also possible to apply a filter on EXTINTn by writing a one to INTn bit in the FILTER register.
This filter is a majority voter, if the condition for an interrupt is true for more than one of the latest
three cycles of CLK_SYNC the interrupt will be set. This will additionally delay the propagation of
the interrupt to the interrupt controller by one or two cycles of CLK_SYNC, see Figure 11-2 on
page 109 and Figure 11-3 on page 109 for examples (FILTER on).
Figure 11-2. Timing Diagram, Synchronous Interrupts, High Level or Rising Edge
CLK_SYNC
EXTINTn/NMI
ISR.INTn:
FILTER off
ISR.INTn:
FILTER on
Figure 11-3. Timing Diagram, Synchronous Interrupts, Low Level or Falling Edge
CLK_SYNC
EXTINTn/NMI
ISR.INTn:
FILTER off
ISR.INTn:
FILTER on
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11.6.3
Non-Maskable Interrupt
The NMI supports the same features as the external interrupts, and is accessed through the
same registers. The description in Section 11.6.1 should be followed, accessing the NMI bit
instead of the INTn bits.
The NMI is non-maskable within the CPU in the sense that it can interrupt any other execution
mode. Still, as for the other external interrupts, the actual NMI input can be enabled and disabled
by accessing the registers in the EIC.
11.6.4
Asynchronous Interrupts
Each external interrupt can be made asynchronous by writing a one to INTn in the ASYNC register. This will route the interrupt signal through the asynchronous path of the module. All edge
interrupts will be interpreted as level interrupts and the filter is disabled. If an interrupt is configured as edge triggered interrupt in asynchronous mode, a zero in EDGE.INTn will be interpreted
as low level, and a one in EDGE.INTn will be interpreted as high level.
EIC_WAKE will be set immediately after the source triggers the interrupt, while the corresponding bit in ISR and the interrupt to the interrupt controller will be set on the next rising edge of
CLK_SYNC. Please refere to Figure 11-4 on page 110 for details.
When CLK_SYNC is stopped only asynchronous interrupts remain active, and any short spike
on this interrupt will wake up the device. EIC_WAKE will restart CLK_SYNC and ISR will be
updated on the first rising edge of CLK_SYNC.
Figure 11-4. Timing Diagram, Asynchronous Interrupts
CLK_SYNC
11.6.5
CLK_SYNC
EXTINTn/NMI
EXTINTn/NMI
ISR.INTn:
rising EDGE or high
LEVEL
ISR.INTn:
rising EDGE or high
LEVEL
EIC_WAKE:
rising EDGE or high
LEVEL
EIC_WAKE:
rising EDGE or high
LEVEL
Wakeup
The external interrupts can be used to wake up the part from sleep modes. The wakeup can be
interpreted in two ways. If the corresponding bit in IMR is one, then the execution starts at the
interrupt handler for this interrupt. If the bit in IMR is zero, then the execution starts from the next
instruction after the sleep instruction.
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11.6.6
Keypad scan support
The External Interrupt Controller also includes support for keypad scanning. The keypad scan
feature is compatible with keypads organized as rows and columns, where a row is shorted
against a column when a key is pressed.
The rows should be connected to the external interrupt pins with pull-ups enabled in the I/O Controller. These external interrupts should be enabled as low level or falling edge interrupts. The
columns should be connected to the available scan pins. The I/O Controller must be configured
to let the required scan pins be controlled by the EIC. Unused external interrupt or scan pins can
be left controlled by the I/O Controller or other peripherals.
The Keypad Scan function is enabled by writing SCAN.EN to 1, which starts the keypad scan
counter. The SCAN outputs are tri-stated, except SCAN[0], which is driven to zero. After
2(SCAN.PRESC+1) RC clock cycles this pattern is left shifted, so that SCAN[1] is driven to zero while
the other outputs are tri-stated. This sequence repeats infinitely, wrapping from the most significant SCAN pin to SCAN[0].
When a key is pressed, the pulled-up row is driven to zero by the column, and an external interrupt triggers. The scanning stops, and the software can then identify the key pressed by the
interrupt status register and the SCAN.PINS value.
The scanning stops whenever there is an active interrupt request from the EIC to the CPU.
When the CPU clears the interrupt flags, scanning resumes.
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11.7
User Interface
Table 11-2.
EIC Register Memory Map
Offset
Register
Register Name
Access
Reset
0x000
Interrupt Enable Register
IER
Write-only
0x00000000
0x004
Interrupt Disable Register
IDR
Write-only
0x00000000
0x008
Interrupt Mask Register
IMR
Read-only
0x00000000
0x00C
Interrupt Status Register
ISR
Read-only
0x00000000
0x010
Interrupt Clear Register
ICR
Write-only
0x00000000
0x014
Mode Register
MODE
Read/Write
0x00000000
0x018
Edge Register
EDGE
Read/Write
0x00000000
0x01C
Level Register
LEVEL
Read/Write
0x00000000
0x020
Filter Register
FILTER
Read/Write
0x00000000
0x024
Test Register
TEST
Read/Write
0x00000000
0x028
Asynchronous Register
ASYNC
Read/Write
0x00000000
0x2C
Scan Register
SCAN
Read/Write
0x00000000
0x030
Enable Register
EN
Write-only
0x00000000
0x034
Disable Register
DIS
Write-only
0x00000000
0x038
Control Register
CTRL
Read-only
0x00000000
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11.7.1
Name:
Interrupt Enable Register
IER
Access Type:
Write-only
Offset:
0x000
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
NMI
7
6
5
4
3
2
1
0
INT7
INT6
INT5
INT4
INT3
INT2
INT1
INT0
• INTn: External Interrupt n
Writing a zero to this bit has no effect.
Writing a one to this bit will set the corresponding bit in IMR.
• NMI: Non-Maskable Interrupt
Writing a zero to this bit has no effect.
Writing a one to this bit will set the corresponding bit in IMR.
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11.7.2
Name:
Interrupt Disable Register
IDR
Access Type:
Write-only
Offset:
0x004
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
NMI
7
6
5
4
3
2
1
0
INT7
INT6
INT5
INT4
INT3
INT2
INT1
INT0
• INTn: External Interrupt n
Writing a zero to this bit has no effect.
Writing a one to this bit will clear the corresponding bit in IMR.
• NMI: Non-Maskable Interrupt
Writing a zero to this bit has no effect.
Writing a one to this bit will clear the corresponding bit in IMR.
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11.7.3
Name:
Interrupt Mask Register
IMR
Access Type:
Read-only
Offset:
0x008
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
NMI
7
6
5
4
3
2
1
0
INT7
INT6
INT5
INT4
INT3
INT2
INT1
INT0
• INTn: External Interrupt n
0: The corresponding interrupt is disabled.
1: The corresponding interrupt is enabled.
This bit is cleared when the corresponding bit in IDR is written to one.
This bit is set when the corresponding bit in IER is written to one.
• NMI: Non-Maskable Interrupt
0: The Non-Maskable Interrupt is disabled.
1: The Non-Maskable Interrupt is enabled.
This bit is cleared when the corresponding bit in IDR is written to one.
This bit is set when the corresponding bit in IER is written to one.
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11.7.4
Name:
Interrupt Status Register
ISR
Access Type:
Read-only
Offset:
0x00C
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
NMI
7
6
5
4
3
2
1
0
INT7
INT6
INT5
INT4
INT3
INT2
INT1
INT0
• INTn: External Interrupt n
0: An interrupt event has not occurred
1: An interrupt event has occurred
This bit is cleared by writing a one to the corresponding bit in ICR.
• NMI: Non-Maskable Interrupt
0: An interrupt event has not occurred
1: An interrupt event has occurred
This bit is cleared by writing a one to the corresponding bit in ICR.
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11.7.5
Name:
Interrupt Clear Register
ICR
Access Type:
Write-only
Offset:
0x010
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
NMI
7
6
5
4
3
2
1
0
INT7
INT6
INT5
INT4
INT3
INT2
INT1
INT0
• INTn: External Interrupt n
Writing a zero to this bit has no effect.
Writing a one to this bit will clear the corresponding bit in ISR.
• NMI: Non-Maskable Interrupt
Writing a zero to this bit has no effect.
Writing a one to this bit will clear the corresponding bit in ISR.
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11.7.6
Name:
Mode Register
MODE
Access Type:
Read/Write
Offset:
0x014
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
NMI
7
6
5
4
3
2
1
0
INT7
INT6
INT5
INT4
INT3
INT2
INT1
INT0
• INTn: External Interrupt n
0: The external interrupt is edge triggered.
1: The external interrupt is level triggered.
• NMI: Non-Maskable Interrupt
0: The Non-Maskable Interrupt is edge triggered.
1: The Non-Maskable Interrupt is level triggered.
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11.7.7
Name:
Edge Register
EDGE
Access Type:
Read/Write
Offset:
0x018
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
NMI
7
6
5
4
3
2
1
0
INT7
INT6
INT5
INT4
INT3
INT2
INT1
INT0
• INTn: External Interrupt n
0: The external interrupt triggers on falling edge.
1: The external interrupt triggers on rising edge.
• NMI: Non-Maskable Interrupt
0: The Non-Maskable Interrupt triggers on falling edge.
1: The Non-Maskable Interrupt triggers on rising edge.
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11.7.8
Name:
Level Register
LEVEL
Access Type:
Read/Write
Offset:
0x01C
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
NMI
7
6
5
4
3
2
1
0
INT7
INT6
INT5
INT4
INT3
INT2
INT1
INT0
• INTn: External Interrupt n
0: The external interrupt triggers on low level.
1: The external interrupt triggers on high level.
• NMI: Non-Maskable Interrupt
0: The Non-Maskable Interrupt triggers on low level.
1: The Non-Maskable Interrupt triggers on high level.
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11.7.9
Filter Register
Name:
FILTER
Access Type:
Read/Write
Offset:
0x020
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
NMI
7
6
5
4
3
2
1
0
INT7
INT6
INT5
INT4
INT3
INT2
INT1
INT0
• INTn: External Interrupt n
0: The external interrupt is not filtered.
1: The external interrupt is filtered.
• NMI: Non-Maskable Interrupt
0: The Non-Maskable Interrupt is not filtered.
1: The Non-Maskable Interrupt is filtered.
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11.7.10
Test Register
Name:
TEST
Access Type:
Read/Write
Offset:
0x024
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
NMI
7
6
5
4
3
2
1
0
INT7
INT6
INT5
INT4
INT3
INT2
INT1
INT0
• TESTEN: Test Enable
0: This bit disables external interrupt test mode.
1: This bit enables external interrupt test mode.
• INTn: External Interrupt n
If TESTEN is 1, the value written to this bit will be the value to the interrupt detector and the value on the pad will be ignored.
• NMI: Non-Maskable Interrupt
If TESTEN is 1, the value written to this bit will be the value to the interrupt detector and the value on the pad will be ignored.
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11.7.11
Asynchronous Register
Name:
ASYNC
Access Type:
Read/Write
Offset:
0x028
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
NMI
7
6
5
4
3
2
1
0
INT7
INT6
INT5
INT4
INT3
INT2
INT1
INT0
• INTn: External Interrupt n
0: The external interrupt is synchronized to CLK_SYNC.
1: The external interrupt is asynchronous.
• NMI: Non-Maskable Interrupt
0: The Non-Maskable Interrupt is synchronized to CLK_SYNC
1: The Non-Maskable Interrupt is asynchronous.
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11.7.12
Name:
Scan Register
SCAN
Access Type:
Read/Write
Offset:
0x2C
Reset Value:
0x0000000
31
30
29
28
27
26
25
24
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
EN
PIN[2:0]
PRESC[4:0]
• EN
0: Keypad scanning is disabled
1: Keypad scanning is enabled
• PRESC
Prescale select for the keypad scan rate:
Scan rate = 2(SCAN.PRESC+1) TRC
The RC clock period can be found in the Electrical Characteristics section.
• PIN
The index of the currently active scan pin. Writing to this bitfield has no effect.
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11.7.13
Enable Register
Name:
EN
Access Type:
Write-only
Offset:
0x030
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
NMI
7
6
5
4
3
2
1
0
INT7
INT6
INT5
INT4
INT3
INT2
INT1
INT0
• INTn: External Interrupt n
Writing a zero to this bit has no effect.
Writing a one to this bit will enable the corresponding external interrupt.
• NMI: Non-Maskable Interrupt
Writing a zero to this bit has no effect.
Writing a one to this bit will enable the Non-Maskable Interrupt.
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11.7.14
Disable Register
Name:
DIS
Access Type:
Write-only
Offset:
0x034
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
NMI
7
6
5
4
3
2
1
0
INT7
INT6
INT5
INT4
INT3
INT2
INT1
INT0
• INTn: External Interrupt n
Writing a zero to this bit has no effect.
Writing a one to this bit will disable the corresponding external interrupt.
• NMI: Non-Maskable Interrupt
Writing a zero to this bit has no effect.
Writing a one to this bit will disable the Non-Maskable Interrupt.
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11.7.15
Control Register
Name:
CTRL
Access Type:
Read-only
Offset:
0x038
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
NMI
7
6
5
4
3
2
1
0
INT7
INT6
INT5
INT4
INT3
INT2
INT1
INT0
• INTn: External Interrupt n
0: The corresponding external interrupt is disabled.
1: The corresponding external interrupt is enabled.
• NMI: Non-Maskable Interrupt
0: The Non-Maskable Interrupt is disabled.
1: The Non-Maskable Interrupt is enabled.
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11.8
Module Configuration
The specific configuration for each EIC instance is listed in the following tables.The module bus
clocks listed here are connected to the system bus clocks. Please refer to the Power Manager
chapter for details.
Table 11-3.
Module Configuration
Feature
EIC
Number of external interrupts, including NMI
9
Table 11-4.
Module Clock Name
Module Name
Clock Name
EIC
CLK_EIC
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12. Flash Controller (FLASHC)
Rev: 2.2.0.3
12.1
Features
• Controls flash block with dual read ports allowing staggered reads.
• Supports 0 and 1 wait state bus access.
• Allows interleaved burst reads for systems with one wait state, outputting one 32-bit word per
clock cycle.
• 32-bit HSB interface for reads from flash array and writes to page buffer.
• 32-bit PB interface for issuing commands to and configuration of the controller.
• 16 lock bits, each protecting a region consisting of (total number of pages in the flash block / 16)
pages.
Regions can be individually protected or unprotected.
Additional protection of the Boot Loader pages.
Supports reads and writes of general-purpose NVM bits.
Supports reads and writes of additional NVM pages.
Supports device protection through a security bit.
Dedicated command for chip-erase, first erasing all on-chip volatile memories before erasing
flash and clearing security bit.
• Interface to Power Manager for power-down of flash-blocks in sleep mode.
•
•
•
•
•
•
•
12.2
Overview
The flash controller (FLASHC) interfaces a flash block with the 32-bit internal HSB bus. Performance for uncached systems with high clock-frequency and one wait state is increased by
placing words with sequential addresses in alternating flash subblocks. Having one read interface per subblock allows them to be read in parallel. While data from one flash subblock is being
output on the bus, the sequential address is being read from the other flash subblock and will be
ready in the next clock cycle.
The controller also manages the programming, erasing, locking and unlocking sequences with
dedicated commands.
12.3
Product dependencies
12.3.1
Power Manager
The HFLASHC has two bus clocks connected: One High speed bus clock (CLK_FLASHC_HSB)
and one Peripheral bus clock (CLK_FLASHC_PB). These clocks are generated by the Power
manager. Bot h clocks are turned on by default, but the user has t o ensure that
CLK_FLASHC_HSB is not turned off before reading the flash or writing the pagebuffer and that
CLK_FLASHC_PB is not turned of before accessing the FLASHC configuration and control
registers.
12.3.2
Interrupt Controller
The FLASHC interrupt lines are connected to internal sources of the interrupt controller. Using
FLASHC interrutps requires the interrupt controller to be programmed first.
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12.4
12.4.1
Functional description
Bus interfaces
The FLASHC has two bus interfaces, one High-Speed Bus (HSB) interface for reads from the
flash array and writes to the page buffer, and one Peripheral Bus (PB) interface for writing commands and control to and reading status from the controller.
12.4.2
Memory organization
To maximize performance for high clock-frequency systems, FLASHC interfaces to a flash block
with two read ports. The flash block has several parameters, given by the design of the flash
block. Refer to the “Memories” chapter for the device-specific values of the parameters.
• p pages (FLASH_P)
• w words in each page and in the page buffer (FLASH_W)
• pw words in total (FLASH_PW)
• f general-purpose fuse bits (FLASH_F)
• 1 security fuse bit
• 1 User Page
12.4.3
User page
The User page is an additional page, outside the regular flash array, that can be used to store
various data, like calibration data and serial numbers. This page is not erased by regular chip
erase. The User page can only be written and erased by proprietary commands. Read accesses
to the User page is performed just as any other read access to the flash. The address map of the
User page is given in Figure 12-1.
12.4.4
Read operations
The FLASHC provides two different read modes:
• 0 wait state (0ws) for clock frequencies < (access time of the flash plus the bus delay)
• 1 wait state (1ws) for clock frequencies < (access time of the flash plus the bus delay)/2
Higher clock frequencies that would require more wait states are not supported by the flash
controller.
The programmer can select the wait states required by writing to the FWS field in the Flash Control Register (FCR). It is the responsibility of the programmer to select a number of wait states
compatible with the clock frequency and timing characteristics of the flash block.
In 0ws mode, only one of the two flash read ports is accessed. The other flash read port is idle.
In 1ws mode, both flash read ports are active. One read port reading the addressed word, and
the other reading the next sequential word.
If the clock frequency allows, the user should use 0ws mode, because this gives the lowest
power consumption for low-frequency systems as only one flash read port is read. Using 1ws
mode has a power/performance ratio approaching 0ws mode as the clock frequency
approaches twice the max frequency of 0ws mode. Using two flash read ports use twice the
power, but also give twice the performance.
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The flash controller supports flash blocks with up to 2^21 word addresses, as displayed in Figure
12-1. Reading the memory space between address pw and 2^21-1 returns an undefined result.
The User page is permanently mapped to word address 2^21.
Table 12-1.
User page addresses
Memory type
Start address, byte sized
Size
Main array
0
pw words = 4pw bytes
User
2^23 = 8388608
128 words = 512 bytes
Figure 12-1. Memory map for the Flash memories
A ll a d d r e s s e s a r e w o r d a d d r e s s e s
2^21+128
2^21
Unused
U nused
U ser page
Flash data array
pw
p w -1
0
F la s h w it h
e x tra p a g e
12.4.5
Quick Page Read
A dedicated command, Quick Page Read (QPR), is provided to read all words in an addressed
page. All bits in all words in this page are AND’ed together, returning a 1-bit result. This result is
placed in the Quick Page Read Result (QPRR) bit in Flash Status Register (FSR). The QPR
command is useful to check that a page is in an erased state. The QPR instruction is much
faster than performing the erased-page check using a regular software subroutine.
12.4.6
Write page buffer operations
The internal memory area reserved for the embedded flash can also be written through a writeonly page buffer. The page buffer is addressed only by the address bits required to address w
words (since the page buffer is word addressable) and thus wrap around within the internal
memory area address space and appear to be repeated within it.
When writing to the page buffer, the PAGEN field in the FCMD register is updated with the page
number corresponding to page address of the latest word written into the page buffer.
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The page buffer is also used for writes to the User page.
Write operations can be prevented by programming the Memory Protection Unit of the CPU.
Writing 8-bit and 16-bit data to the page buffer is not allowed and may lead to unpredictable data
corruption.
Page buffer write operations are performed with 4 wait states.
Writing to the page buffer can only change page buffer bits from one to zero, ie writing
0xaaaaaaaa to a page buffer location that has the value 0x00000000, will not change the page
buffer value. The only way to change a bit from zero to one, is to reset the entire page buffer with
the Clear Page Buffer command.
The page buffer is not automatically reset after a page write. The programmer should do this
manually by issuing the Clear Page Buffer flash command. This can be done after a page write,
or before the page buffer is loaded with data to be stored to the flash page.
Example: Writing a word into word address 130 of a flash with 128 words in the page buffer.
PAGEN will be updated with the value 1, and the word will be written into word 2 in the page
buffer.
12.4.7
Writing words to a page that is not completely erased
This can be used for EEPROM emulation, i.e. writes with granularity of one word instead of an
entire page. Only words that are in an completely erased state (0xFFFFFFFF) can be changed.
The procedure is as follows:
1. Clear page buffer
2. Write to the page buffer the result of the logical bitwise AND operation between the
contents of the flash page and the new data to write. Only words that were in an erased
state can be changed from the original page.
3. Write Page.
12.5
Flash commands
The FLASHC offers a command set to manage programming of the flash memory, locking and
unlocking of regions, and full flash erasing. See chapter 12.8.3 for a complete list of commands.
To run a command, the field CMD of the Flash Command Register (FCMD) has to be written
with the command number. As soon as the FCMD register is written, the FRDY flag is automatically cleared. Once the current command is complete, the FRDY flag is automatically set. If an
interrupt has been enabled by setting the bit FRDY in FCR, the interrupt line of the flash controller is activated. All flash commands except for Quick Page Read (QPR) will generate an interrupt
request upon completion if FRDY is set.
After a command has been written to FCMD, the programming algorithm should wait until the
command has been executed before attempting to read instructions or data from the flash or
writing to the page buffer, as the flash will be busy. The waiting can be performed either by polling the Flash Status Register (FSR) or by waiting for the flash ready interrupt. The command
written to FCMD is initiated on the first clock cycle where the HSB bus interface in FLASHC is
IDLE. The user must make sure that the access pattern to the FLASHC HSB interface contains
an IDLE cycle so that the command is allowed to start. Make sure that no bus masters such as
DMA controllers are performing endless burst transfers from the flash. Also, make sure that the
CPU does not perform endless burst transfers from flash. This is done by letting the CPU enter
sleep mode after writing to FCMD, or by polling FSR for command completion. This polling will
result in an access pattern with IDLE HSB cycles.
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All the commands are protected by the same keyword, which has to be written in the eight highest bits of the FCMD register. Writing FCMD with data that does not contain the correct key
and/or with an invalid command has no effect on the flash memory; however, the PROGE flag is
set in the Flash Status Register (FSR). This flag is automatically cleared by a read access to the
FSR register.
Writing a command to FCMD while another command is being executed has no effect on the
flash memory; however, the PROGE flag is set in the Flash Status Register (FSR). This flag is
automatically cleared by a read access to the FSR register.
If the current command writes or erases a page in a locked region, or a page protected by the
BOOTPROT fuses, the command has no effect on the flash memory; however, the LOCKE flag
is set in the FSR register. This flag is automatically cleared by a read access to the FSR register.
12.5.1
Write/erase page operation
Flash technology requires that an erase must be done before programming. The entire flash can
be erased by an Erase All command. Alternatively, pages can be individually erased by the
Erase Page command.
The User page can be written and erased using the mechanisms described in this chapter.
After programming, the page can be locked to prevent miscellaneous write or erase sequences.
Locking is performed on a per-region basis, so locking a region locks all pages inside the region.
Additional protection is provided for the lowermost address space of the flash. This address
space is allocated for the Boot Loader, and is protected both by the lock bit(s) corresponding to
this address space, and the BOOTPROT[2:0] fuses.
Data to be written are stored in an internal buffer called page buffer. The page buffer contains w
words. The page buffer wraps around within the internal memory area address space and
appears to be repeated by the number of pages in it. Writing of 8-bit and 16-bit data to the page
buffer is not allowed and may lead to unpredictable data corruption.
Data must be written to the page buffer before the programming command is written to the Flash
Command Register FCMD. The sequence is as follows:
• Reset the page buffer with the Clear Page Buffer command.
• Fill the page buffer with the desired contents, using only 32-bit access.
• Programming starts as soon as the programming key and the programming command are
written to the Flash Command Register. The PAGEN field in the Flash Command Register
(FCMD) must contain the address of the page to write. PAGEN is automatically updated
when writing to the page buffer, but can also be written to directly. The FRDY bit in the Flash
Status Register (FSR) is automatically cleared when the page write operation starts.
• When programming is completed, the bit FRDY in the Flash Status Register (FSR) is set. If
an interrupt was enabled by setting the bit FRDY in FCR, the interrupt line of the flash
controller is set.
Two errors can be detected in the FSR register after a programming sequence:
• Programming Error: A bad keyword and/or an invalid command have been written in the
FCMD register.
• Lock Error: The page to be programmed belongs to a locked region. A command must be
executed to unlock the corresponding region before programming can start.
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12.5.2
Erase All operation
The entire memory is erased if the Erase All command (EA) is written to the Flash Command
Register (FCMD). Erase All erases all bits in the flash array. The User page is not erased. All
flash memory locations, the general-purpose fuse bits, and the security bit are erased (reset to
0xFF) after an Erase All.
The EA command also ensures that all volatile memories, such as register file and RAMs, are
erased before the security bit is erased.
Erase All operation is allowed only if no regions are locked, and the BOOTPROT fuses are programmed with a region size of 0. Thus, if at least one region is locked, the bit LOCKE in FSR is
set and the command is cancelled. If the bit LOCKE has been written to 1 in FCR, the interrupt
line rises.
When the command is complete, the bit FRDY bit in the Flash Status Register (FSR) is set. If an
interrupt has been enabled by setting the bit FRDY in FCR, the interrupt line of the flash controller is set. Two errors can be detected in the FSR register after issuing the command:
• Programming Error: A bad keyword and/or an invalid command have been written in the
FCMD register.
• Lock Error: At least one lock region to be erased is protected, or BOOTPROT is different from
0. The erase command has been refused and no page has been erased. A Clear Lock Bit
command must be executed previously to unlock the corresponding lock regions.
12.5.3
Region lock bits
The flash block has p pages, and these pages are grouped into 16 lock regions, each region
containing p/16 pages. Each region has a dedicated lock bit preventing writing and erasing
pages in the region. After production, the device may have some regions locked. These locked
regions are reserved for a boot or default application. Locked regions can be unlocked to be
erased and then programmed with another application or other data.
To lock or unlock a region, the commands Lock Region Containing Page (LP) and Unlock
Region Containing Page (UP) are provided. Writing one of these commands, together with the
number of the page whose region should be locked/unlocked, performs the desired operation.
One error can be detected in the FSR register after issuing the command:
• Programming Error: A bad keyword and/or an invalid command have been written in the
FCMD register.
The lock bits are implemented using the lowest 16 general-purpose fuse bits. This means that
lock bits can also be set/cleared using the commands for writing/erasing general-purpose fuse
bits, see chapter 12.6. The general-purpose bit being in an erased (1) state means that the
region is unlocked.
The lowermost pages in the Flash can additionally be protected by the BOOTPROT fuses, see
Section 12.6.
12.6
General-purpose fuse bits
Each flash block has a number of general-purpose fuse bits that the application programmer can
use freely. The fuse bits can be written and erased using dedicated commands, and read
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through a dedicated Peripheral Bus address. Some of the general-purpose fuse bits are
reserved for special purposes, and should not be used for other functions.:
Table 12-2.
General-purpose fuses with special functions
GeneralPurpose fuse
number
Name
Usage
15:0
LOCK
Region lock bits.
EPFL
External Privileged Fetch Lock. Used to prevent the CPU from
fetching instructions from external memories when in privileged
mode. This bit can only be changed when the security bit is
cleared. The address range corresponding to external
memories is device-specific, and not known to the flash
controller. This fuse bit is simply routed out of the CPU or bus
system, the flash controller does not treat this fuse in any
special way, except that it can not be altered when the security
bit is set.
If the security bit is set, only an external JTAG Chip Erase can
clear EPFL. No internal commands can alter EPFL if the
security bit is set.
When the fuse is erased (i.e. "1"), the CPU can execute
instructions fetched from external memories. When the fuse is
programmed (i.e. "0"), instructions can not be executed from
external memories.
BOOTPROT
Used to select one of eight different bootloader sizes. Pages
included in the bootloader area can not be erased or
programmed except by a JTAG chip erase. BOOTPROT can
only be changed when the security bit is cleared.
If the security bit is set, only an external JTAG Chip Erase can
clear BOOTPROT, and thereby allow the pages protected by
BOOTPROT to be programmed. No internal commands can
alter BOOTPROT or the pages protected by BOOTPROT if the
security bit is set.
16
19:17
The BOOTPROT fuses protects the following address space for the Boot Loader:
Table 12-3.
Boot Loader area specified by BOOTPROT
BOOTPROT
Pages protected by
BOOTPROT
Size of protected
memory
7
None
0
6
0-1
1kByte
5
0-3
2kByte
4
0-7
4kByte
3
0-15
8kByte
2
0-31
16kByte
1
0-63
32kByte
0
0-127
64kByte
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To erase or write a general-purpose fuse bit, the commands Write General-Purpose Fuse Bit
(WGPB) and Erase General-Purpose Fuse Bit (EGPB) are provided. Writing one of these commands, together with the number of the fuse to write/erase, performs the desired operation.
An entire General-Purpose Fuse byte can be written at a time by using the Program GP Fuse
Byte (PGPFB) instruction. A PGPFB to GP fuse byte 2 is not allowed if the flash is locked by the
security bit. The PFB command is issued with a parameter in the PAGEN field:
• PAGEN[2:0] - byte to write
• PAGEN[10:3] - Fuse value to write
All General-Purpose fuses can be erased by the Erase All General-Purpose fuses (EAGP) command. An EAGP command is not allowed if the flash is locked by the security bit.
Two errors can be detected in the FSR register after issuing these commands:
• Programming Error: A bad keyword and/or an invalid command have been written in the
FCMD register.
• Lock Error: A write or erase of any of the special-function fuse bits in Table 12-3 was
attempted while the flash is locked by the security bit.
The lock bits are implemented using the lowest 16 general-purpose fuse bits. This means that
the 16 lowest general-purpose fuse bits can also be written/erased using the commands for
locking/unlocking regions, see Section 12.5.3.
12.7
Security bit
The security bit allows the entire chip to be locked from external JTAG or other debug access for
code security. The security bit can be written by a dedicated command, Set Security Bit (SSB).
Once set, the only way to clear the security bit is through the JTAG Chip Erase command.
Once the Security bit is set, the following Flash controller commands will be unavailable and
return a lock error if attempted:
• Write General-Purpose Fuse Bit (WGPB) to BOOTPROT or EPFL fuses
• Erase General-Purpose Fuse Bit (EGPB) to BOOTPROT or EPFL fuses
• Program General-Purpose Fuse Byte (PGPFB) of fuse byte 2
• Erase All General-Purpose Fuses (EAGPF)
One error can be detected in the FSR register after issuing the command:
• Programming Error: A bad keyword and/or an invalid command have been written in the
FCMD register.
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12.8
User interface
12.8.1
Address map
The following addresses are used by the FLASHC. All offsets are relative to the base address
allocated to the flash controller.
Table 12-4.
Flash controller register mapping
Offset
Register
Name
Access
Reset
state
0x0
Flash Control Register
FCR
R/W
0
0x4
Flash Command Register
FCMD
R/W
0
0x8
Flash Status Register
FSR
R/W
0 (*)
0xc
Flash General Purpose Fuse Register Hi
FGPFRHI
R
NA (*)
0x10
Flash General Purpose Fuse Register Lo
FGPFRLO
R
NA (*)
(*) The value of the Lock bits is dependent of their programmed state. All other bits in FSR are 0.
All bits in FGPFR and FCFR are dependent on the programmed state of the fuses they map to.
Any bits in these registers not mapped to a fuse read 0.
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12.8.2
Flash Control Register
Name:
FCR
Access Type:
Read/Write
Offset:
0x00
Reset value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
FWS
-
-
PROGE
LOCKE
-
FRDY
• FRDY: Flash Ready Interrupt Enable
0: Flash Ready does not generate an interrupt.
1: Flash Ready generates an interrupt.
• LOCKE: Lock Error Interrupt Enable
0: Lock Error does not generate an interrupt.
1: Lock Error generates an interrupt.
• PROGE: Programming Error Interrupt Enable
0: Programming Error does not generate an interrupt.
1: Programming Error generates an interrupt.
• FWS: Flash Wait State
0: The flash is read with 0 wait states.
1: The flash is read with 1 wait state.
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12.8.3
Flash Command Register
Name:
FCMD
Access Type:
Read/Write
Offset:
0x04
Reset value:
0x00000000
The FCMD can not be written if the flash is in the process of performing a flash command. Doing
so will cause the FCR write to be ignored, and the PROGE bit to be set.
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
KEY
23
22
21
20
PAGEN [15:8]
15
14
13
12
PAGEN [7:0]
7
6
-
-
5
4
CMD
• CMD: Command
This field defines the flash command. Issuing any unused command will cause the Programming Error flag to be set, and the
corresponding interrupt to be requested if the PROGE bit in FCR is set.
Table 12-5.
Set of commands
Command
Value
Mnemonic
No operation
0
NOP
Write Page
1
WP
Erase Page
2
EP
Clear Page Buffer
3
CPB
Lock region containing given Page
4
LP
Unlock region containing given Page
5
UP
Erase All
6
EA
Write General-Purpose Fuse Bit
7
WGPB
Erase General-Purpose Fuse Bit
8
EGPB
Set Security Bit
9
SSB
Program GP Fuse Byte
10
PGPFB
Erase All GPFuses
11
EAGPF
Quick Page Read
12
QPR
Write User Page
13
WUP
Erase User Page
14
EUP
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Table 12-5.
Set of commands
Command
Value
Mnemonic
Quick Page Read User Page
15
QPRUP
High speed mode enable
16
HSEN
HIgh speed mode disable
17
HSDIS
• PAGEN: Page number
The PAGEN field is used to address a page or fuse bit for certain operations. In order to simplify programming, the PAGEN field
is automatically updated every time the page buffer is written to. For every page buffer write, the PAGEN field is updated with the
page number of the address being written to. Hardware automatically masks writes to the PAGEN field so that only bits
representing valid page numbers can be written, all other bits in PAGEN are always 0. As an example, in a flash with 1024
pages (page 0 - page 1023), bits 15:10 will always be 0.
Table 12-6.
Semantic of PAGEN field in different commands
Command
PAGEN description
No operation
Not used
Write Page
The number of the page to write
Clear Page Buffer
Not used
Lock region containing given Page
Page number whose region should be locked
Unlock region containing given Page
Page number whose region should be unlocked
Erase All
Not used
Write General-Purpose Fuse Bit
GPFUSE #
Erase General-Purpose Fuse Bit
GPFUSE #
Set Security Bit
Not used
Program GP Fuse Byte
WriteData[7:0], ByteAddress[2:0]
Erase All GP Fuses
Not used
Quick Page Read
Page number
Write User Page
Not used
Erase User Page
Not used
Quick Page Read User Page
Not used
• KEY: Write protection key
This field should be written with the value 0xA5 to enable the command defined by the bits of the register. If the field is written
with a different value, the write is not performed and no action is started.
This field always reads as 0.
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12.8.4
Flash Status Register
Name:
FSR
Access Type:
Read/Write
Offset:
0x08
Reset value:
0x00000000
31
30
29
28
27
26
25
24
LOCK15
LOCK14
LOCK13
LOCK12
LOCK11
LOCK10
LOCK9
LOCK8
23
22
21
20
19
18
17
16
LOCK7
LOCK6
LOCK5
LOCK4
LOCK3
LOCK2
LOCK1
LOCK0
15
14
13
12
11
10
9
8
-
-
-
-
5
4
3
2
1
0
QPRR
SECURITY
PROGE
LOCKE
-
FRDY
FSZ
7
-
6
• FRDY: Flash Ready Status
0: The flash controller is busy and the application must wait before running a new command.
1: The flash controller is ready to run a new command.
• LOCKE: Lock Error Status
Automatically cleared when FSR is read.
0: No programming of at least one locked lock region has happened since the last read of FSR.
1: Programming of at least one locked lock region has happened since the last read of FSR.
• PROGE: Programming Error Status
Automatically cleared when FSR is read.
0: No invalid commands and no bad keywords were written in the Flash Command Register FCMD.
1: An invalid command and/or a bad keyword was/were written in the Flash Command Register FCMD.
• SECURITY: Security Bit Status
0: The security bit is inactive.
1: The security bit is active.
• QPRR: Quick Page Read Result
0: The result is zero, i.e. the page is not erased.
1: The result is one, i.e. the page is erased.
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• FSZ: Flash Size
The size of the flash. Not all device families will provide all flash sizes indicated in the table.
Table 12-7.
Flash size
FSZ
Flash Size
0
32 KByte
1
64 kByte
2
128 kByte
3
256 kByte
4
384 kByte
5
512 kByte
6
768 kByte
7
1024 kByte
• LOCKx: Lock Region x Lock Status
0: The corresponding lock region is not locked.
1: The corresponding lock region is locked.
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12.8.5
Flash General Purpose Fuse Register High
Name:
FGPFRHI
Access Type:
Read
Offset:
0x0C
Reset value:
N/A
31
30
29
28
27
26
25
24
GPF63
GPF62
GPF61
GPF60
GPF59
GPF58
GPF57
GPF56
23
22
21
20
19
18
17
16
GPF55
GPF54
GPF53
GPF52
GPF51
GPF50
GPF49
GPF48
15
14
13
12
11
10
9
8
GPF47
GPF46
GPF45
GPF44
GPF43
GPF42
GPF41
GPF40
7
6
5
4
3
2
1
0
GPF39
GPF38
GPF37
GPF36
GPF35
GPF34
GPF33
GPF32
This register is only used in systems with more than 32 GP fuses.
• GPFxx: General Purpose Fuse xx
0: The fuse has a written/programmed state.
1: The fuse has an erased state.
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12.8.6
Flash General Purpose Fuse Register Low
Name:
FGPFRLO
Access Type:
Read
Offset:
0x10
Reset value:
N/A
31
30
29
28
27
26
25
24
GPF31
GPF30
GPF29
GPF28
GPF27
GPF26
GPF25
GPF24
23
22
21
20
19
18
17
16
GPF23
GPF22
GPF21
GPF20
GPF19
GPF18
GPF17
GPF16
15
14
13
12
11
10
9
8
GPF15
GPF14
GPF13
GPF12
GPF11
GPF10
GPF09
GPF08
7
6
5
4
3
2
1
0
GPF07
GPF06
GPF05
GPF04
GPF03
GPF02
GPF01
GPF00
• GPFxx: General Purpose Fuse xx
0: The fuse has a written/programmed state.
1: The fuse has an erased state.
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12.9
Fuses Settings
The flash block contains 32 general purpose fuses. These 32 fuses can be found in the Flash
General Purpose Fuse Register Low (FGPFRLO) of the Flash Controller (FLASHC).
Some of the FGPFRLO fuses have defined meanings outside the FLASHC and are described in
this section.
The general purpose fuses are set by a JTAG chip erase.
12.9.1
Flash General Purpose Fuse Register Low (FGPFRLO)
Table 12-8.
FGPFRLO Register Description
31
30
29
GPF31
GPF30
GPF29
23
22
21
28
27
BODEN
20
BODHYST
19
BODLEVEL[3:0]
15
14
13
26
18
25
BODLEVEL[5:4]
17
BOOTPROT
12
24
16
EPFL
11
10
9
8
3
2
1
0
LOCK[15:8]
7
6
5
4
LOCK[7:0]
• BODEN: Brown Out Detector Enable
Table 12-9.
BODEN Field Description
BODEN
Description
0x0
Brown Out Detector (BOD) disabled
0x1
BOD enabled, BOD reset enabled
0x2
BOD enabled, BOD reset disabled
0x3
BOD disabled
• BODHYST: Brown Out Detector Hystersis
0: The BOD hysteresis is disabled
1: The BOD hysteresis is enabled
• BODLEVEL: Brown Out Detector Trigger Level
This controls the voltage trigger level for the Brown out detector. For value description refer to Electrical Characteristics chapter.
If the BODLEVEL is set higher than VDDCORE and enabled by fuses, the part will be in constant reset. To recover from this
situation, apply an external voltage on VDDCORE that is higher than the BOD Trigger level and disable the BOD.
• LOCK, EPFL, BOOTPROT
These are Flash controller fuses and are described in the FLASHC chapter.
12.9.2
Default Fuse Value
The devices are shipped with the FGPFRLO register value: 0xFFF7FFFF:
• GPF31 reserved for future use
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• GPF30 reserved for future use
• GPF29 reserved for future use
• BODEN fuses set to 0b11. BOD is disabled.
• BODHYST fuse set to 0b1. The BOD hystersis is enabled.
• BODLEVEL fuses set to 0b111111. This is the minimum voltage trigger level for BOD.
• BOOTPROT fuses set to 0b011. The bootloader protected size is 8KBytes.
• EPFL fuse set to 0b1. External privileged fetch is not locked.
• LOCK fuses set to 0b1111111111111111. No region locked.
The devices are shipped with 2 bootloader configuration words in the flash user pages:
at adress 808001F8h and 808001FCh. See also the USB DFU bootloader user guide document.
After the JTAG chip erase command, the FGPFRLO register value is 0xFFFFFFFF.
12.10 Serial number in the factory page
Each device has a unique 120 bits serial number located in the factory page and readable from
address 0x80800204 to 0x80800212.
12.11 Module configuration
The specific configuration for the FLASHC instance is listed in the following tables.The module
bus clocks listed here are connected to the system bus clocks according to the table in the
Power Manager section.
Table 12-10. Module Configuration
Feature
FLASH
Devices
ATUC3A3256S
ATUC3A3256
ATUC3A4256S
ATUC3A4256
ATUC3A3128S
ATUC3A3128
ATUC3A4128S
ATUC3A4128
ATUC3A364S
ATUC3A364
ATUC3A464
ATUC3A464
Flash size
256Kbytes
128Kbytes
64Kbytes
Number of
pages
512
512
512
Page size
512 bytes
512 bytes
512 bytes
Table 12-11. Module Clock Name
Module name
Clock name
Clock name
FLASHC
CLK_FLASHC_HSB
CLK_FLASHC_PB
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13. HSB Bus Matrix (HMATRIX)
Rev: 2.3.0.2
13.1
Features
•
•
•
•
•
•
•
•
•
•
•
13.2
User Interface on peripheral bus
Configurable Number of Masters (Up to sixteen)
Configurable Number of Slaves (Up to sixteen)
One Decoder for Each Master
Three Different Memory Mappings for Each Master (Internal and External boot, Remap)
One Remap Function for Each Master
Programmable Arbitration for Each Slave
– Round-Robin
– Fixed Priority
Programmable Default Master for Each Slave
– No Default Master
– Last Accessed Default Master
– Fixed Default Master
One Cycle Latency for the First Access of a Burst
Zero Cycle Latency for Default Master
One Special Function Register for Each Slave (Not dedicated)
Overview
The Bus Matrix implements a multi-layer bus structure, that enables parallel access paths
between multiple High Speed Bus (HSB) masters and slaves in a system, thus increasing the
overall bandwidth. The Bus Matrix interconnects up to 16 HSB Masters to up to 16 HSB Slaves.
The normal latency to connect a master to a slave is one cycle except for the default master of
the accessed slave which is connected directly (zero cycle latency). The Bus Matrix provides 16
Special Function Registers (SFR) that allow the Bus Matrix to support application specific
features.
13.3
Product Dependencies
In order to use this module, other parts of the system must be configured correctly, as described
below.
13.3.1
Clocks
The clock for the HMATRIX bus interface (CLK_HMATRIX) is generated by the Power Manager.
This clock is enabled at reset, and can be disabled in the Power Manager. It is recommended to
disable the HMATRIX before disabling the clock, to avoid freezing the HMATRIX in an undefined
state.
13.4
13.4.1
Functional Description
Special Bus Granting Mechanism
The Bus Matrix provides some speculative bus granting techniques in order to anticipate access
requests from some masters. This mechanism reduces latency at first access of a burst or single
transfer. This bus granting mechanism sets a different default master for every slave.
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At the end of the current access, if no other request is pending, the slave remains connected to
its associated default master. A slave can be associated with three kinds of default masters: no
default master, last access master and fixed default master.
13.4.1.1
No Default Master
At the end of the current access, if no other request is pending, the slave is disconnected from
all masters. No Default Master suits low-power mode.
13.4.1.2
Last Access Master
At the end of the current access, if no other request is pending, the slave remains connected to
the last master that performed an access request.
13.4.1.3
Fixed Default Master
At the end of the current access, if no other request is pending, the slave connects to its fixed
default master. Unlike last access master, the fixed master does not change unless the user
modifies it by a software action (field FIXED_DEFMSTR of the related SCFG).
To change from one kind of default master to another, the Bus Matrix user interface provides the
Slave Configuration Registers, one for each slave, that set a default master for each slave. The
Slave Configuration Register contains two fields: DEFMSTR_TYPE and FIXED_DEFMSTR. The
2-bit DEFMSTR_TYPE field selects the default master type (no default, last access master, fixed
default master), whereas the 4-bit FIXED_DEFMSTR field selects a fixed default master provided that DEFMSTR_TYPE is set to fixed default master. Please refer to the Bus Matrix user
interface description.
13.4.2
Arbitration
The Bus Matrix provides an arbitration mechanism that reduces latency when conflict cases
occur, i.e. when two or more masters try to access the same slave at the same time. One arbiter
per HSB slave is provided, thus arbitrating each slave differently.
The Bus Matrix provides the user with the possibility of choosing between 2 arbitration types for
each slave:
1. Round-Robin Arbitration (default)
2. Fixed Priority Arbitration
This choice is made via the field ARBT of the Slave Configuration Registers (SCFG).
Each algorithm may be complemented by selecting a default master configuration for each
slave.
When a re-arbitration must be done, specific conditions apply. See Section 13.4.2.1 ”Arbitration
Rules” on page 148.
13.4.2.1
Arbitration Rules
Each arbiter has the ability to arbitrate between two or more different master requests. In order
to avoid burst breaking and also to provide the maximum throughput for slave interfaces, arbitration may only take place during the following cycles:
1. Idle Cycles: When a slave is not connected to any master or is connected to a master
which is not currently accessing it.
2. Single Cycles: When a slave is currently doing a single access.
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3. End of Burst Cycles: When the current cycle is the last cycle of a burst transfer. For
defined length burst, predicted end of burst matches the size of the transfer but is managed differently for undefined length burst.
4. Slot Cycle Limit: When the slot cycle counter has reached the limit value indicating that
the current master access is too long and must be broken.
• Undefined Length Burst Arbitration
In order to avoid long slave handling during undefined length bursts (INCR), the Bus Matrix provides specific logic in order to re-arbitrate before the end of the INCR transfer. A predicted end
of burst is used as a defined length burst transfer and can be selected from among the following
five possibilities:
1. Infinite: No predicted end of burst is generated and therefore INCR burst transfer will
never be broken.
2. One beat bursts: Predicted end of burst is generated at each single transfer inside the
INCP transfer.
3. Four beat bursts: Predicted end of burst is generated at the end of each four beat
boundary inside INCR transfer.
4. Eight beat bursts: Predicted end of burst is generated at the end of each eight beat
boundary inside INCR transfer.
5. Sixteen beat bursts: Predicted end of burst is generated at the end of each sixteen beat
boundary inside INCR transfer.
This selection can be done through the field ULBT of the Master Configuration Registers
(MCFG).
• Slot Cycle Limit Arbitration
The Bus Matrix contains specific logic to break long accesses, such as very long bursts on a
very slow slave (e.g., an external low speed memory). At the beginning of the burst access, a
counter is loaded with the value previously written in the SLOT_CYCLE field of the related Slave
Configuration Register (SCFG) and decreased at each clock cycle. When the counter reaches
zero, the arbiter has the ability to re-arbitrate at the end of the current byte, half word or word
transfer.
13.4.2.2
Round-Robin Arbitration
This algorithm allows the Bus Matrix arbiters to dispatch the requests from different masters to
the same slave in a round-robin manner. If two or more master requests arise at the same time,
the master with the lowest number is first serviced, then the others are serviced in a round-robin
manner.
There are three round-robin algorithms implemented:
1. Round-Robin arbitration without default master
2. Round-Robin arbitration with last default master
3. Round-Robin arbitration with fixed default master
• Round-Robin Arbitration without Default Master
This is the main algorithm used by Bus Matrix arbiters. It allows the Bus Matrix to dispatch
requests from different masters to the same slave in a pure round-robin manner. At the end of
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the current access, if no other request is pending, the slave is disconnected from all masters.
This configuration incurs one latency cycle for the first access of a burst. Arbitration without
default master can be used for masters that perform significant bursts.
• Round-Robin Arbitration with Last Default Master
This is a biased round-robin algorithm used by Bus Matrix arbiters. It allows the Bus Matrix to
remove the one latency cycle for the last master that accessed the slave. In fact, at the end of
the current transfer, if no other master request is pending, the slave remains connected to the
last master that performed the access. Other non privileged masters still get one latency cycle if
they want to access the same slave. This technique can be used for masters that mainly perform
single accesses.
• Round-Robin Arbitration with Fixed Default Master
This is another biased round-robin algorithm. It allows the Bus Matrix arbiters to remove the one
latency cycle for the fixed default master per slave. At the end of the current access, the slave
remains connected to its fixed default master. Every request attempted by this fixed default master will not cause any latency whereas other non privileged masters will still get one latency
cycle. This technique can be used for masters that mainly perform single accesses.
13.4.2.3
Fixed Priority Arbitration
This algorithm allows the Bus Matrix arbiters to dispatch the requests from different masters to
the same slave by using the fixed priority defined by the user. If two or more master requests are
active at the same time, the master with the highest priority number is serviced first. If two or
more master requests with the same priority are active at the same time, the master with the
highest number is serviced first.
For each slave, the priority of each master may be defined through the Priority Registers for
Slaves (PRAS and PRBS).
13.4.3
Slave and Master assignation
The index number assigned to Bus Matrix slaves and masters are described in Memories
chapter.
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13.5
User Interface
Table 13-1.
HMATRIX Register Memory Map
Offset
Register
Name
Access
Reset Value
0x0000
Master Configuration Register 0
MCFG0
Read/Write
0x00000002
0x0004
Master Configuration Register 1
MCFG1
Read/Write
0x00000002
0x0008
Master Configuration Register 2
MCFG2
Read/Write
0x00000002
0x000C
Master Configuration Register 3
MCFG3
Read/Write
0x00000002
0x0010
Master Configuration Register 4
MCFG4
Read/Write
0x00000002
0x0014
Master Configuration Register 5
MCFG5
Read/Write
0x00000002
0x0018
Master Configuration Register 6
MCFG6
Read/Write
0x00000002
0x001C
Master Configuration Register 7
MCFG7
Read/Write
0x00000002
0x0020
Master Configuration Register 8
MCFG8
Read/Write
0x00000002
0x0024
Master Configuration Register 9
MCFG9
Read/Write
0x00000002
0x0028
Master Configuration Register 10
MCFG10
Read/Write
0x00000002
0x002C
Master Configuration Register 11
MCFG11
Read/Write
0x00000002
0x0030
Master Configuration Register 12
MCFG12
Read/Write
0x00000002
0x0034
Master Configuration Register 13
MCFG13
Read/Write
0x00000002
0x0038
Master Configuration Register 14
MCFG14
Read/Write
0x00000002
0x003C
Master Configuration Register 15
MCFG15
Read/Write
0x00000002
0x0040
Slave Configuration Register 0
SCFG0
Read/Write
0x00000010
0x0044
Slave Configuration Register 1
SCFG1
Read/Write
0x00000010
0x0048
Slave Configuration Register 2
SCFG2
Read/Write
0x00000010
0x004C
Slave Configuration Register 3
SCFG3
Read/Write
0x00000010
0x0050
Slave Configuration Register 4
SCFG4
Read/Write
0x00000010
0x0054
Slave Configuration Register 5
SCFG5
Read/Write
0x00000010
0x0058
Slave Configuration Register 6
SCFG6
Read/Write
0x00000010
0x005C
Slave Configuration Register 7
SCFG7
Read/Write
0x00000010
0x0060
Slave Configuration Register 8
SCFG8
Read/Write
0x00000010
0x0064
Slave Configuration Register 9
SCFG9
Read/Write
0x00000010
0x0068
Slave Configuration Register 10
SCFG10
Read/Write
0x00000010
0x006C
Slave Configuration Register 11
SCFG11
Read/Write
0x00000010
0x0070
Slave Configuration Register 12
SCFG12
Read/Write
0x00000010
0x0074
Slave Configuration Register 13
SCFG13
Read/Write
0x00000010
0x0078
Slave Configuration Register 14
SCFG14
Read/Write
0x00000010
0x007C
Slave Configuration Register 15
SCFG15
Read/Write
0x00000010
0x0080
Priority Register A for Slave 0
PRAS0
Read/Write
0x00000000
0x0084
Priority Register B for Slave 0
PRBS0
Read/Write
0x00000000
0x0088
Priority Register A for Slave 1
PRAS1
Read/Write
0x00000000
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Table 13-1.
HMATRIX Register Memory Map (Continued)
Offset
Register
Name
Access
Reset Value
0x008C
Priority Register B for Slave 1
PRBS1
Read/Write
0x00000000
0x0090
Priority Register A for Slave 2
PRAS2
Read/Write
0x00000000
0x0094
Priority Register B for Slave 2
PRBS2
Read/Write
0x00000000
0x0098
Priority Register A for Slave 3
PRAS3
Read/Write
0x00000000
0x009C
Priority Register B for Slave 3
PRBS3
Read/Write
0x00000000
0x00A0
Priority Register A for Slave 4
PRAS4
Read/Write
0x00000000
0x00A4
Priority Register B for Slave 4
PRBS4
Read/Write
0x00000000
0x00A8
Priority Register A for Slave 5
PRAS5
Read/Write
0x00000000
0x00AC
Priority Register B for Slave 5
PRBS5
Read/Write
0x00000000
0x00B0
Priority Register A for Slave 6
PRAS6
Read/Write
0x00000000
0x00B4
Priority Register B for Slave 6
PRBS6
Read/Write
0x00000000
0x00B8
Priority Register A for Slave 7
PRAS7
Read/Write
0x00000000
0x00BC
Priority Register B for Slave 7
PRBS7
Read/Write
0x00000000
0x00C0
Priority Register A for Slave 8
PRAS8
Read/Write
0x00000000
0x00C4
Priority Register B for Slave 8
PRBS8
Read/Write
0x00000000
0x00C8
Priority Register A for Slave 9
PRAS9
Read/Write
0x00000000
0x00CC
Priority Register B for Slave 9
PRBS9
Read/Write
0x00000000
0x00D0
Priority Register A for Slave 10
PRAS10
Read/Write
0x00000000
0x00D4
Priority Register B for Slave 10
PRBS10
Read/Write
0x00000000
0x00D8
Priority Register A for Slave 11
PRAS11
Read/Write
0x00000000
0x00DC
Priority Register B for Slave 11
PRBS11
Read/Write
0x00000000
0x00E0
Priority Register A for Slave 12
PRAS12
Read/Write
0x00000000
0x00E4
Priority Register B for Slave 12
PRBS12
Read/Write
0x00000000
0x00E8
Priority Register A for Slave 13
PRAS13
Read/Write
0x00000000
0x00EC
Priority Register B for Slave 13
PRBS13
Read/Write
0x00000000
0x00F0
Priority Register A for Slave 14
PRAS14
Read/Write
0x00000000
0x00F4
Priority Register B for Slave 14
PRBS14
Read/Write
0x00000000
0x00F8
Priority Register A for Slave 15
PRAS15
Read/Write
0x00000000
0x00FC
Priority Register B for Slave 15
PRBS15
Read/Write
0x00000000
0x0110
Special Function Register 0
SFR0
Read/Write
–
0x0114
Special Function Register 1
SFR1
Read/Write
–
0x0118
Special Function Register 2
SFR2
Read/Write
–
0x011C
Special Function Register 3
SFR3
Read/Write
–
0x0120
Special Function Register 4
SFR4
Read/Write
–
0x0124
Special Function Register 5
SFR5
Read/Write
–
0x0128
Special Function Register 6
SFR6
Read/Write
–
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Table 13-1.
HMATRIX Register Memory Map (Continued)
Offset
Register
Name
Access
Reset Value
0x012C
Special Function Register 7
SFR7
Read/Write
–
0x0130
Special Function Register 8
SFR8
Read/Write
–
0x0134
Special Function Register 9
SFR9
Read/Write
–
0x0138
Special Function Register 10
SFR10
Read/Write
–
0x013C
Special Function Register 11
SFR11
Read/Write
–
0x0140
Special Function Register 12
SFR12
Read/Write
–
0x0144
Special Function Register 13
SFR13
Read/Write
–
0x0148
Special Function Register 14
SFR14
Read/Write
–
0x014C
Special Function Register 15
SFR15
Read/Write
–
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13.5.1
Name:
Master Configuration Registers
MCFG0...MCFG15
Access Type:
Read/Write
Offset:
0x00 - 0x3C
Reset Value:
0x00000002
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
–
–
–
–
–
7
6
5
4
3
2
1
0
–
–
–
–
–
ULBT
• ULBT: Undefined Length Burst Type
0: Infinite Length Burst
No predicted end of burst is generated and therefore INCR bursts coming from this master cannot be broken.
1: Single Access
The undefined length burst is treated as a succession of single accesses, allowing re-arbitration at each beat of the INCR burst.
2: Four Beat Burst
The undefined length burst is split into a four-beat burst, allowing re-arbitration at each four-beat burst end.
3: Eight Beat Burst
The undefined length burst is split into an eight-beat burst, allowing re-arbitration at each eight-beat burst end.
4: Sixteen Beat Burst
The undefined length burst is split into a sixteen-beat burst, allowing re-arbitration at each sixteen-beat burst end.
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13.5.2
Name:
Slave Configuration Registers
SCFG0...SCFG15
Access Type:
Read/Write
Offset:
0x40 - 0x7C
Reset Value:
0x00000010
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
ARBT
23
22
21
20
19
18
17
16
–
–
15
14
13
12
11
10
9
8
–
–
–
–
–
–
–
–
7
6
5
4
3
2
1
0
FIXED_DEFMSTR
DEFMSTR_TYPE
SLOT_CYCLE
• ARBT: Arbitration Type
0: Round-Robin Arbitration
1: Fixed Priority Arbitration
• FIXED_DEFMSTR: Fixed Default Master
This is the number of the Default Master for this slave. Only used if DEFMSTR_TYPE is 2. Specifying the number of a master
which is not connected to the selected slave is equivalent to setting DEFMSTR_TYPE to 0.
The size of this field depends on the number of masters. This size is log2(number of masters).
• DEFMSTR_TYPE: Default Master Type
0: No Default Master
At the end of the current slave access, if no other master request is pending, the slave is disconnected from all masters.
This results in a one cycle latency for the first access of a burst transfer or for a single access.
1: Last Default Master
At the end of the current slave access, if no other master request is pending, the slave stays connected to the last master having
accessed it.
This results in not having one cycle latency when the last master tries to access the slave again.
2: Fixed Default Master
At the end of the current slave access, if no other master request is pending, the slave connects to the fixed master the number
that has been written in the FIXED_DEFMSTR field.
This results in not having one cycle latency when the fixed master tries to access the slave again.
• SLOT_CYCLE: Maximum Number of Allowed Cycles for a Burst
When the SLOT_CYCLE limit is reached for a burst, it may be broken by another master trying to access this slave.
This limit has been placed to avoid locking a very slow slave when very long bursts are used.
This limit must not be very small. Unreasonably small values break every burst and the Bus Matrix arbitrates without performing
any data transfer. 16 cycles is a reasonable value for SLOT_CYCLE.
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13.5.3
Name:
Bus Matrix Priority Registers A For Slaves
PRAS0...PRAS15
Access Type:
Read/Write
Offset:
-
Reset Value:
0x00000000
31
30
–
–
23
22
–
–
15
14
–
–
7
6
–
–
29
28
M7PR
21
20
M5PR
13
12
M3PR
5
4
M1PR
27
26
–
–
19
18
–
–
11
10
–
–
3
2
–
–
25
24
M6PR
17
16
M4PR
9
8
M2PR
1
0
M0PR
• MxPR: Master x Priority
Fixed priority of Master x for accessing the selected slave. The higher the number, the higher the priority.
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13.5.4
Name:
Priority Registers B For Slaves
PRBS0...PRBS15
Access Type:
Read/Write
Offset:
-
Reset Value:
0x00000000
31
30
–
–
23
22
–
–
15
14
–
–
7
6
–
–
29
28
M15PR
21
20
M13PR
13
12
M11PR
5
4
M9PR
27
26
–
–
19
18
–
–
11
10
–
–
3
2
–
–
25
24
M14PR
17
16
M12PR
9
8
M10PR
1
0
M8PR
• MxPR: Master x Priority
Fixed priority of Master x for accessing the selected slave. The higher the number, the higher the priority.
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13.5.5
Name:
Special Function Registers
SFR0...SFR15
Access Type:
Read/Write
Offset:
0x110 - 0x115
Reset Value:
-
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
SFR
23
22
21
20
SFR
15
14
13
12
SFR
7
6
5
4
SFR
• SFR: Special Function Register Fields
Those registers are not a HMATRIX specific register. The field of those will be defined where they are used.
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13.6
Bus Matrix Connections
Accesses to unused areas returns an error result to the master requesting such an access.
The bus matrix has the several masters and slaves. Each master has its own bus and its own
decoder, thus allowing a different memory mapping per master. The master number in the table
below can be used to index the HMATRIX control registers. For example, HMATRIX MCFG0
register is associated with the CPU Data master interface.
Table 13-2.
High Speed Bus masters
Master 0
CPU Data
Master 1
CPU Instruction
Master 2
CPU SAB
Master 3
PDCA
Master 4
DMACA HSB Master 1
Master 5
DMACA HSB Master 2
Master 6
USBB DMA
Each slave has its own arbiter, thus allowing a different arbitration per slave. The slave number
in the table below can be used to index the HMATRIX control registers. For example, HMATRIX
SCFG4 register is associated with the Embedded CPU SRAM Slave Interface.
Table 13-3.
High Speed Bus slaves
Slave 0
Internal Flash
Slave 1
HSB-PB Bridge A
Slave 2
HSB-PB Bridge B
Slave 3
AES
Slave 4
Embedded CPU SRAM
Slave 5
USBB DPRAM
Slave 6
EBI
Slave 7
DMACA Slave
Slave 8
HRAMC0
Slave 9
HRAMC1
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Figure 13-1. HMATRIX Master / Slave Connections
0
CPU
Instruction
1
CPU SAB
2
PDCA
3
DMACA
Master 0
4
DMACA
Master 1
5
USBB
DMA
6
HMATRIX MASTERS
CPU Data
Internal Flash
HSB-PB
Bridge A
HSB-PB
Bridge B
AES
Embedded
CPU SRAM
USB DPRAM
EBI
DMACA
Slave
HRAMC0
HRAMC1
HMATRIX SLAVES
0
1
2
3
4
5
6
7
8
9
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14. External Bus Interface (EBI)
Rev.: 1.7.0.0
14.1
Features
• Optimized for application memory space support
• Integrates three external memory controllers:
– Static Memory Controller (SMC)
– SDRAM Controller (SDRAMC)
– Error Corrected Code (ECCHRS) controller
• Additional logic for NAND Flash/SmartMediaTM and CompactFlashTM support
– NAND Flash support: 8-bit as well as 16-bit devices are supported
– CompactFlash support: all modes (Attribute Memory, Common Memory, I/O, True IDE) are
supported but the signals _IOIS16 (I/O and True IDE modes) and _ATA SEL (True IDE mode)
are not handled.
• Optimized external bus:16-bit data bus
– Up to 24-bit Address Bus, Up to 8-Mbytes Addressable
– Optimized pin multiplexing to reduce latencies on external memories
• Up to 6 Chip Selects, Configurable Assignment:
– Static Memory Controller on Chip Select 0
– SDRAM Controller or Static Memory Controller on Chip Select 1
– Static Memory Controller on Chip Select 2, Optional NAND Flash support
– Static Memory Controller on Chip Select 3, Optional NAND Flash support
– Static Memory Controller on Chip Select 4, Optional CompactFlashTM support
– Static Memory Controller on Chip Select 5, Optional CompactFlashTM support
14.2
Overview
The External Bus Interface (EBI) is designed to ensure the successful data transfer between
several external devices and the embedded memory controller of an 32-bit AVR device. The
Static Memory, SDRAM and ECCHRS Controllers are all featured external memory controllers
on the EBI. These external memory controllers are capable of handling several types of external
memory and peripheral devices, such as SRAM, PROM, EPROM, EEPROM, Flash, and
SDRAM.
The EBI also supports the CompactFlash and the NAND Flash/SmartMedia protocols via integrated circuitry that greatly reduces the requirements for external components. Furthermore, the
EBI handles data transfers with up to six external devices, each assigned to six address spaces
defined by the embedded memory controller. Data transfers are performed through a 16-bit, an
address bus of up to 23 bits, up to six chip select lines (NCS[5:0]), and several control pins that
are generally multiplexed between the different external memory controllers.
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14.3
Block Diagram
Figure 14-1. EBI Block Diagram
INTC
SDRAMC_irq
ECCHRS_irq
EBI
HMATRIX
HSB
DATA[15:0]
SDRAM
Controller
NWE1
NWE0
Static
Memory
Controller
NRD
NCS[5:0]
ADDR[23:0]
CAS
ECCHRS
Controller
NAND Flash
SmartMedia
Logic
SFR
registers
Compact
FLash
Logic
MUX
Logic
I/O
Controller
RAS
SDA10
SDWE
SDCK
SDCKE
NANDOE
NANDWE
Address
Decoders
Chip Select
Assignor
CFRNW
CFCE1
CFCE2
HSB-PB
Bridge
NWAIT
Peripheral Bus
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14.4
I/O Lines Description
Table 14-1.
EBI I/O Lines Description
Pin Name
Alternate
Name
Pin Description
Type
Active
Level
EBI common lines
DATA[15:0]
Data Bus
I/O
SMC dedicated lines
ADDR[1]
SMC Address Bus Line 1
Output
ADDR[12]
SMC Address Bus Line 12
Output
ADDR[15]
SMC Address Bus Line 15
Output
SMC Address Bus Line [23:18]
Output
NCS[0]
SMC Chip Select Line 0
Output
Low
NWAIT
SMC External Wait Signal
Input
Low
ADDR[23:18]
SDRAMC dedicated lines
SDCK
SDRAM Clock
Output
SDCKE
SDRAM Clock Enable
Output
High
SDWE
SDRAM Write Enable
Output
Low
SDA10
SDRAM Address Bus Line 10
Output
Low
Row and Column Signal
Output
Low
Low
RAS - CAS
CompactFlash dedicated lines
CFCE1 CFCE2
CompactFlash Chip Enable
Output
CFRNW
CompactFlash Read Not Write Signal
Output
NAND Flash/SmartMedia dedicated lines
NANDOE
NAND Flash Output Enable
Output
Low
NANDWE
NAND Flash Write Enable
Output
Low
SMC Chip Select Line 1
SDRAMC Chip Select Line 0
Output
Low
SDRAMC DQM1
SMC Address Bus Line 0 or Byte Select 1
Output
SMC/SDRAMC shared lines
NCS[1]
NCS[1]
SDCS0
ADDR[0]
DQM0
ADDR[0]-NBS0
ADDR[11:2]
ADDR[9:0]
ADDR[11:2]
SDRAMC Address Bus Lines [9:0]
SMC Address Bus Lines [11:2]
Output
ADDR[14:13]
ADDR[9:0]
ADDR[14:13]
SDRAMC Address Bus Lines [12:11]
SMC Address Bus Lines [14:13]
Output
ADDR[16]
BA0
ADDR[16]
SDRAMC Bank 0
SMC Address Bus Line 16
Output
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Pin Name
ADDR[17]
Alternate
Name
Pin Description
BA1
ADDR[17]
SDRAMC Bank 1
SMCAddress Bus Line 17
Type
Active
Level
Output
SMC/CompactFlash shared lines
NRD
NRD
CFNOE
SMC Read Signal
CompactFlash CFNOE
Output
Low
NWE0
NWE0-NWE
CFNWE
SMC Write Enable10 or Write enable
CompactFlash CFNWE
Output
Low
NCS[4]
NCS[4]
CFCS[0]
SMC Chip Select Line 4
CompactFlash Chip Select Line 0
Output
Low
NCS[5]
NCS[5]
CFCS[1]
SMC Chip Select Line 5
CompactFlash Chip Select Line 1
Output
Low
SMC/NAND Flash/SmartMedia shared lines
NCS[2]
NCS[2]
NANDCS[0]
SMC Chip Select Line 2
NANDFlash/SmartMedia Chip Select Line
0
Output
Low
NCS[3]
NCS[3]
NANDCS[1]
SMC Chip Select Line 3
NANDFlash/SmartMedia Chip Select Line
1
Output
Low
SDRAMC/SMC/CompactFlash shared lines
NWE1
14.5
DQM1/
NWE1-NBS1/
CFNIORD
SDRAMC DQM1
SMC Write Enable1 or Byte Select 1
CompactFlash CFNIORD
Output
Product Dependencies
In order to use this module, other parts of the system must be configured correctly, as described
below.
14.5.1
I/O Lines
The pins used for interfacing the compliant external devices may be multiplexed with I/O Controller lines. The user must first configure the I/O Controller to assign the EBI pins to their
peripheral functions.
14.5.2
Power Management
To prevent bus errors EBI operation must be terminated before entering sleep mode.
14.5.3
Clocks
A number of clocks can be selected as source for the EBI. The selected clock must be enabled
by the Power Manager.
The following clock sources are available:
• CLK_EBI
• CLK_SDRAMC
• CLK_SMC
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• CLK_ECCHRS
Refer to Table 14-2 on page 165 to configure those clocks.
Table 14-2.
EBI Clocks Configuration
Type of the Interfaced Device
Clocks
type
SDRAM
SRAM, PROM,
EPROM,
EEPROM, Flash
NandFlash
SmartMedia
CompactFlash
CLK_EBI
HSB
X
X
X
X
CLK_SDRAMC
PB
X
CLK_SMC
PB
X
X
X
CLK_ECCHRS
PB
Clocks name
14.5.4
X
Interrupts
The EBI interface has two interrupt lines connected to the Interrupt Controller:
• SDRAMC_IRQ: Interrupt signal coming from the SDRAMC
• ECCHRS_IRQ: Interrupt signal coming from the ECCHRS
Handling the EBI interrupt requires configuring the interrupt controller before configuring the EBI.
14.5.5
HMATRIX
The EBI interface is connected to the HMATRIX Special Function Register 6 (SFR6). The user
must first write to this HMATRIX.SFR6 to configure the EBI correctly.
Table 14-3.
SFR6 Bit
Number
EBI Special Function Register Fields Description
Bit name
[31:6]
Description
Reserved
0 = Chip Select 5 (NCS[5]) is connected to a Static Memory device. For each
access to the NCS[5] memory space, all related pins act as SMC pins
5
CS5A
1 = Chip Select 5 (NCS[5]) is connected to a CompactFlash device. For each
access to the NCS[5] memory space, all related pins act as CompactFlash
pins
0 = Chip Select 4 (NCS[4]) is connected to a Static Memory device. For each
access to the NCS[4] memory space, all related pins act as SMC pins
4
CS4A
1 = Chip Select 4 (NCS[4]) is connected to a CompactFlash device. For each
access to the NCS[4] memory space, all related pins act as CompactFlash
pins
0 = Chip Select 3 (NCS[3]) is connected to a Static Memory device. For each
access to the NCS[3] memory space, all related pins act as SMC pins
3
CS3A
1 = Chip Select 3 (NCS[3]) is connected to a NandFlash or a SmartMedia
device. For each access to the NCS[3] memory space, all related pins act as
NandFlash or SmartMedia pins
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Table 14-3.
SFR6 Bit
Number
EBI Special Function Register Fields Description
Bit name
Description
0 = Chip Select 2 (NCS[2]) is connected to a Static Memory device. For each
access to the NCS[2] memory space, all related pins act as SMC pins
2
1
0
14.6
CS2A
CS1A
1 = Chip Select 2 (NCS[2]) is connected to a NandFlash or a SmartMedia
device. For each access to the NCS[2] memory space, all related pins act as
NandFlash or SmartMedia pins
0 = Chip Select 1 (NCS[1]) is connected to a Static Memory device. For each
access to the NCS[1] memory space, all related pins act as SMC pins
1 = Chip Select 1 (NCS[1]) is connected to a SDRAM device. For each access
to the NCS[1] memory space, all related pins act as SDRAM pins
Reserved
Functional Description
The EBI transfers data between the internal HSB bus (handled by the HMATRIX) and the external memories or peripheral devices. It controls the waveforms and the parameters of the
external address, data and control busses and is composed of the following elements:
• The Static Memory Controller (SMC)
• The SDRAM Controller (SDRAMC)
• The ECCHRS Controller (ECCHRS)
• A chip select assignment feature that assigns an HSB address space to the external devices
• A multiplex controller circuit that shares the pins between the different memory controllers
• Programmable CompactFlash support logic
• Programmable SmartMedia and NAND Flash support logic
14.6.1
Bus Multiplexing
The EBI offers a complete set of control signals that share the 16-bit data lines, the address
lines of up to 24 bits and the control signals through a multiplex logic operating in function of the
memory area requests.
Multiplexing is specifically organized in order to guarantee the maintenance of the address and
output control lines at a stable state while no external access is being performed. Multiplexing is
also designed to respect the data float times defined in the Memory Controllers. Furthermore,
refresh cycles of the SDRAM are executed independently by the SDRAMC without delaying the
other external memory controller accesses.
14.6.2
Static Memory Controller
For information on the Static Memory Controller, refer to the Static Memory Controller Section.
14.6.3
SDRAM Controller
Writing a one to the HMATRIX.SFR6.CS1A bit enables the SDRAM logic.
For information on the SDRAM Controller, refer to the SDRAM Section.
14.6.4
ECCHRS Controller
For information on the ECCHRS Controller, refer to the ECCHRS Section.
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14.6.5
CompactFlash Support
The External Bus Interface integrates circuitry that interfaces to CompactFlash devices.
The CompactFlash logic is driven by the SMC on the NCS[4] and/or NCS[5] address space.
Writing to the HMATRIX.SFR6.CS4A and/or HMATRIX.SFR6.CS5A bits the appropriate value
enables this logic. Access to an external CompactFlash device is then made by accessing the
address space reserved to NCS[4] and/or NCS[5].
All CompactFlash modes (Attribute Memory, Common Memory, I/O and True IDE) are supported but the signals _IOWR, _IOIS16 (I/O and True IDE modes) and _ATA SEL (True IDE
mode) are not handled.
14.6.5.1
I/O Mode, Common Memory Mode, Attribute Memory Mode and True IDE Mode
Within the NCS[4] and/or NCS[5] address space, the current transfer address is used to distinguish I/O mode, common memory mode, attribute memory mode and True IDE mode.
The different modes are accessed through a specific memory mapping as illustrated on Figure
14-2 on page 167. ADDR[23:21] bits of the transfer address are used to select the desired mode
as described in Table 14-4 on page 167.
Figure 14-2. CompactFlash Memory Mapping
True IDE Alternate Mode Space
Offset 0x00E0 0000
True IDE Mode Space
Offset 0x00C0 0000
CF Address Space
I/O Mode Space
Offset 0x0080 0000
Common Memory Mode Space
Offset 0x0040 0000
Attribute Memory Mode Space
Offset 0x0000 0000
Note:
The ADDR[22] I/O line is used to drive the REG signal of the CompactFlash Device (except in
True IDE mode).
Table 14-4.
CompactFlash Mode Selection
ADDR[23:21]
Mode Base Address
000
Attribute Memory
010
Common Memory
100
I/O Mode
110
True IDE Mode
111
Alternate True IDE Mode
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14.6.5.2
CFCE1 and CFCE2 signals
To cover all types of access, the SMC must be alternatively set to drive 8-bit data bus or 16-bit
data bus. The odd byte access on the DATA[7:0] bus is only possible when the SMC is configured to drive 8-bit memory devices on the corresponding NCS pin (NCS[4] or NCS[5]). The Data
Bus Width (DBW) field in the SMC Mode (MODE) register of the NCS[4] and/or NCS[5] address
space must be written as shown in Table 14-5 on page 168 to enable the required access type.
NBS1 and NBS0 are the byte selection signals from SMC and are available when the SMC is set
in Byte Select mode on the corresponding Chip Select.
The CFCE1 and CFCE2 waveforms are identical to the corresponding NCSx waveform. For
details on these waveforms and timings, refer to the SMC Section.
Table 14-5.
CFCE1 and CFCE2 Truth Table
SMC Access
Mode
Mode
CFCE2
CFCE1
DBW
Comment
Attribute Memory
NBS1
NBS0
16 bits
Access to Even Byte on
DATA[7:0]
Byte Select
Byte Select
NBS1
NBS0
16bits
Access to Even Byte on
DATA[7:0]
Access to Odd Byte on
DATA[15:8]
1
0
8 bits
Access to Odd Byte on
DATA[7:0]
Common Memory
NBS1
NBS0
16 bits
Access to Even Byte on
DATA[7:0]
Access to Odd Byte on
DATA[15:8]
1
0
8 bits
Access to Odd Byte on
DATA[7:0]
I/O Mode
Byte Select
True IDE Mode
Task File
Data Register
1
1
0
0
8 bits
Access to Even Byte on
DATA[7:0]
Access to Odd Byte on
DATA[7:0]
16 bits
Access to Even Byte on
DATA[7:0]
Access to Odd Byte on
DATA[15:8]
Byte Select
Alternate True IDE Mode
Control Register
Alternate Status
Read
0
1
Don’t
Care
Access to Even Byte on
DATA[7:0]
Drive Address
0
1
8 bits
Access to Odd Byte on
DATA[7:0]
Standby Mode or
Address Space is
not assigned to
CF
1
1
–
–
Don’t Care
–
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14.6.5.3
Read/Write signals
In I/O mode and True IDE mode, the CompactFlash logic drives the read command signals of
the SMC on CFNIORD signal, while the CFNOE and CFNWE signals are deactivated. Likewise,
in common memory mode and attribute memory mode, the SMC signals are driven on the
CFNOE and CFNWE signals, while the CFNIORD is deactivated. Figure 14-3 on page 169 demonstrates a schematic representation of this logic.
Attribute memory mode, common memory mode and I/O mode are supported by writing the
address setup and hold time on the NCS[4] (and/or NCS[5]) chip select to the appropriate values. For details on these signal waveforms, please refer to the section: Setup and Hold Cycles
of the SMC Section.
Figure 14-3. CompactFlash Read/Write Control Signals
EBI
SMC
Compact Flash Logic
A23
1
1
0
1
1
A22
NRD
NWR0/NWE
Table 14-6.
CFNIORD
0
1
1
CompactFlash Mode Selection
Mode Base Address
CFNOE
CFNWE
CFNIORD
NRD_NOE
NWR0_NWE
1
I/O Mode
1
1
NRD_NOE
True IDE Mode
0
1
NRD_NOE
Attribute Memory
Common Memory
14.6.5.4
CFNOE
CFNWE
0
Multiplexing of CompactFlash signals on EBI pins
Table 14-7 on page 170 and Table on page 170 illustrate the multiplexing of the CompactFlash
logic signals with other EBI signals on the EBI pins. The EBI pins in Table 14-7 on page 170 are
strictly dedicated to the CompactFlash interface as soon as the HMATRIX.SFR6.CS4A and/or
HMATRIX.SFR6.CS5A bits is/are written. These pins must not be used to drive any other memory devices.
The EBI pins in Table 14-8 on page 170 remain shared between all memory areas when the corresponding CompactFlash interface is enabled (CS4A = 1 and/or CS5A = 1).
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Table 14-7.
Dedicated CompactFlash Interface Multiplexing
CompactFlash Signals
EBI Signals
Pins
CS4A = 1
NCS[4]
CFCS0
NCS[5]
Table 14-8.
CS5A = 1
CS4A = 0
CS5A = 0
NCS[4]
CFCS1
NCS[5]
Shared CompactFlash Interface Multiplexing
Access to
CompactFlash Device
14.6.5.5
Pins
CompactFlash Signals
NRD
CFNOE
NWE0
CFNWE
NWE1
CFNIORD
CFRNW
CFRNW
Application example
Figure 14-4 on page 171 illustrates an example of a CompactFlash application. CFCS0 and
CFRNW signals are not directly connected to the CompactFlash slot 0, but do control the direction and the output enable of the buffers between the EBI and the CompactFlash Device. The
timing of the CFCS0 signal is identical to the NCS[4] signal. The CFRNW signal remains valid
throughout the transfer, as does the address bus. The CompactFlash _WAIT signal is connected to the NWAIT input of the Static Memory Controller. For details on these waveforms and
timings, refer to the SMC Section.
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Figure 14-4. CompactFlash Application Example
CompactFlash
Connector
EBI
D[15:0]
DATA[15:0]
DIR /OE
CFRNW
NCS[4]
_CD1
Pxx
_CD2
/OE
ADDR[10:0]
ADDR[22]
_REG
NRD
_OE
NWE0
_WE
NWE1
_IORD
ADDR[23]
14.6.6
A[10:0]
_IOWR
CFCE1
_CE1
CFCE2
_CE2
NWAIT
_WAIT
SmartMedia and NAND Flash Support
The EBI integrates circuitry that interfaces to SmartMedia and NAND Flash devices.
The NAND Flash logic is driven by the Static Memory Controller on the NCS[2] (and/or NCS[3])
address space. Writing to the HMATRIX.SFR6.CS2A (and/or HMATRIX.SFR6.CS3A) bit the
appropriate value enables the NAND Flash logic. Access to an external NAND Flash device is
then made by accessing the address space reserved to NCS[2] (and/or NCS[3]).
The NAND Flash logic drives the read and write command signals of the SMC on the NANDOE
and NANDWE signals when the NCS[2] (and/or NCS[3]) signal is active. NANDOE and
NANDWE are invalidated as soon as the transfer address fails to lie in the NCS[2] (and/or
NCS[3]) address space. See Figure 14-5 on page 172 for more informations. For details on
these waveforms, refer to the SMC Section.
The SmartMedia device is connected the same way as the NAND Flash device.
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Figure 14-5. NAND Flash Signal Multiplexing on EBI Pins
EBI
NandFlash
Logic
SMC
NCS[2]/[3]
NRD
NANDOE
NANDWE
NWR0_NWE
14.6.6.1
NAND Flash signals
The address latch enable and command latch enable signals on the NAND Flash device are
driven by address bits ADDR[22] and ADDR[21] of the EBI address bus. The user should note
that any bit on the EBI address bus can also be used for this purpose. The command, address or
data words on the data bus of the NAND Flash device are distinguished by using their address
within the NCSx address space. The chip enable (CE) signal of the device and the ready/busy
(R/B) signals are connected to I/O Controller lines. The CE signal then remains asserted even
when NCSx is not selected, preventing the device from returning to standby mode.
Figure 14-6. NAND Flash Application Example
DATA[7:0]
AD[7:0]
ADDR[22]
ALE
ADDR[21]
CLE
EBI
Note:
NandFlash
NANDOE
NOE
NANDWE
NWE
NCS[2/3]
Or I/O line
CE
I/O line
R/B
The External Bus Interfaces is also able to support 16-bits devices.
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14.7
14.7.1
Application Example
Hardware Interface
Table 14-9.
EBI Pins and External Static Devices Connections
Pins of the Interfaced Device
2 x 8-bit
Static
Devices
8-bit Static
Device
Pins name
Controller
16-bit Static
Device
SMC
DATA[7:0]
D[7:0]
D[7:0]
D[7:0]
DATA[15:0
–
D[15:8]
D[15:8]
ADDR[0]
A[0]
–
NBS0(2)
ADDR[1]
A[1]
A[0]
A[0]
A[23:2]
A[22:1]
A[22:1]
NCS[0] - NCS[5]
CS
CS
CS
NRD
OE
OE
OE
ADDR[23:2]
NWE0
WE
NWE1
Note:
–
WE
(1)
WE
WE
(1)
NBS1(2)
1. NWE1 enables upper byte writes. NWE0 enables lower byte writes.
2. NBS1 enables upper byte writes. NBS0 enables lower byte writes.
Table 14-10. EBI Pins and External Devices Connections
Pins of the Interfaced Device
SDRAM
Pins name
Controller
Compact
Flash
SDRAMC
Compact
Flash
True IDE Mode
Smart Media
or
NAND Flash
SMC
DATA[7:0]
D[7:0]
D[7:0]
D[7:0]
AD[7:0]
DATA[15:8]
D[15:8]
D[15:8]
D[15:8]
AD[15:8]
ADDR[0]
DQM0
A[0]
A[0]
–
ADDR[1]
–
A[1]
A[1]
–
A[8:0]
A[10:2]
A[10:2]
–
ADDR[11]
A[9]
–
–
–
SDA10
A[10]
–
–
–
–
–
–
–
A[12:11]
–
–
–
ADDR[15]
–
–
–
–
ADDR[16]
BA0
–
–
–
ADDR[17]
BA1
–
–
–
–
–
–
–
ADDR[10:2]
ADDR[12]
ADDR[14:13]
ADDR[20:18]
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Table 14-10. EBI Pins and External Devices Connections (Continued)
Pins of the Interfaced Device
SDRAM
Pins name
Controller
Compact
Flash
SDRAMC
Compact
Flash
True IDE Mode
Smart Media
or
NAND Flash
SMC
ADDR[21]
–
–
–
CLE(3)
ADDR[22]
–
REG
REG
ALE(3)
NCS[0]
–
–
–
–
NCS[1]
SDCS[0]
–
–
–
NCS[2]
–
–
–
CE0
NCS[3]
–
–
NCS[4]
–
–
CFCS0
(1)
CFCS1
(1)
CE1
CFCS0
(1)
–
CFCS1
(1)
–
NCS[5]
–
NANDOE
–
–
–
OE
NANDWE
–
–
–
WE
NRD
–
OE
–
–
NWE0
–
WE
WE
–
NWE1
DQM1
IOR
–
(1)
CFRNW
–
CFCE1
–
CE1
CS0
–
CFCE2
–
CE2
CS1
–
SDCK
CLK
–
–
–
SDCKE
CKE
–
–
–
RAS
RAS
–
–
–
CAS
CAS
–
–
–
SDWE
WE
–
–
–
NWAIT
–
WAIT
WAIT
–
–
CD1 or CD2
CD1 or CD2
–
–
–
–
RDY
(2)
Pxx
(2)
Pxx
Note:
CFRNW
IOR
(1)
CFRNW
–
1. Not directly connected to the CompactFlash slot. Permits the control of the bidirectional buffer
between the EBI data bus and the CompactFlash slot.
2. Any I/O Controller line.
3. The CLE and ALE signals of the NAND Flash device may be driven by any address bit. For
details, see Section 14.6.6.
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14.7.2
Connection Examples
Figure 14-7 on page 175shows an example of connections between the EBI and external
devices.
Figure 14-7. EBI Connections to Memory Devices
EBI
DATA[15:0]
RAS
CAS
SDCK
SDCKE
SDWE
ADDR[0]
NWE1
NRD
NWE0
DATA[7:0]
SDCK
SDCKE
SDWE
RAS
CAS
ADDR[0]
SDRAM
2Mx8
DATA[15:8]
D[7:0]
CS
CLK
CKE
WE
RAS
CAS
DQM
A[9:0]
A[10]
A[11]
BA0
BA1
ADDR[11:2]
SDA10
ADDR[13]
ADDR[16]
ADDR[17]
SDCK
SDCKE
SDWE
RAS
CAS
NWE1
SDRAM
2Mx8
D[7:0]
CS
CLK
CKE
WE
RAS
CAS
DQM
A[9:0]
A[10]
A[11]
BA0
BA1
ADDR[11:2]
SDA10
ADDR[13]
ADDR[16]
ADDR[17]
SDA10
ADDR[17:1]
NCS[1]
SRAM
128Kx8
D[7:0]
NCS[0]
NRD
NWE0
DATA[15:8]
DATA[7:0]
NCS[0]
CS
OE
WE
A[16:0]
SRAM
128Kx8
D[7:0]
ADDR[17:1]
NCS[0]
NRD
NWE1
A[16:0]
ADDR[17:1]
CS
OE
WE
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15. Static Memory Controller (SMC)
Rev. 1.0.6.5
15.1
Features
•
•
•
•
•
•
•
•
•
•
•
•
15.2
6 chip selects available
16-Mbytes address space per chip select
8- or 16-bit data bus
Word, halfword, byte transfers
Byte write or byte select lines
Programmable setup, pulse and hold time for read signals per chip select
Programmable setup, pulse and hold time for write signals per chip select
Programmable data float time per chip select
Compliant with LCD module
External wait request
Automatic switch to slow clock mode
Asynchronous read in page mode supported: page size ranges from 4 to 32 bytes
Overview
The Static Memory Controller (SMC) generates the signals that control the access to the external memory devices or peripheral devices. It has 6 chip selects and a 24-bit address bus. The
16-bit data bus can be configured to interface with 8-16-bit external devices. Separate read and
write control signals allow for direct memory and peripheral interfacing. Read and write signal
waveforms are fully parametrizable.
The SMC can manage wait requests from external devices to extend the current access. The
SMC is provided with an automatic slow clock mode. In slow clock mode, it switches from userprogrammed waveforms to slow-rate specific waveforms on read and write signals. The SMC
supports asynchronous burst read in page mode access for page size up to 32 bytes.
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15.3
Block Diagram
Figure 15-1. SMC Block Diagram (AD_MSB=23)
NCS[5:0]
HMatrix
NCS[5:0]
NRD
SMC
Chip Select
NRD
NWR0/NWE
NWE0
A0/NBS0
ADDR[0]
NWR1/NBS1
SMC
Power
Manager
A1/NWR2/NBS2
CLK_SMC
NWE1
EBI
Mux Logic
A[AD_MSB:2]
D[15:0]
NWAIT
I/O
Controller
ADDR[1]
ADDR[AD_MSB:2]
DATA[15:0]
NWAIT
User Interface
Peripheral Bus
15.4
I/O Lines Description
Table 15-1.
15.5
I/O Lines Description
Pin Name
Pin Description
Type
Active Level
NCS[5:0]
Chip Select Lines
Output
Low
NRD
Read Signal
Output
Low
NWR0/NWE
Write 0/Write Enable Signal
Output
Low
A0/NBS0
Address Bit 0/Byte 0 Select Signal
Output
Low
NWR1/NBS1
Write 1/Byte 1 Select Signal
Output
Low
A[23:2]
Address Bus
Output
D[15:0]
Data Bus
NWAIT
External Wait Signal
Input/Output
Input
Low
Product Dependencies
In order to use this module, other parts of the system must be configured correctly, as described
below.
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15.5.1
I/O Lines
The SMC signals pass through the External Bus Interface (EBI) module where they are multiplexed. The user must first configure the I/O Controller to assign the EBI pins corresponding to
SMC signals to their peripheral function. If the I/O lines of the EBI corresponding to SMC signals
are not used by the application, they can be used for other purposes by the I/O Controller.
15.5.2
Clocks
The clock for the SMC bus interface (CLK_SMC) is generated by the Power Manager. This clock
is enabled at reset, and can be disabled in the Power Manager. It is recommended to disable the
SMC before disabling the clock, to avoid freezing the SMC in an undefined state.
15.6
15.6.1
Functional Description
Application Example
Figure 15-2. SMC Connections to Static Memory Devices
D0-D15
A0/NBS0
NWR0/NWE
NWR1/NBS1
D0-D7
128K x 8
SRAM
D8-D15
D0-D7
A0-A16
NRD
NWR0/NWE
OE
WE
D0-D7
CS
CS
NCS0
NCS1
NCS2
NCS3
NCS4
NCS5
128K x 8
SRAM
A2-A18
A0-A16
NRD
NWR1/NBS1
A2-A18
OE
WE
Static Memory
Controller
A2-A18
15.6.2
External Memory Mapping
The SMC provides up to 24 address lines, A[23:0]. This allows each chip select line to address
up to 16Mbytes of memory.
If the physical memory device connected on one chip select is smaller than 16Mbytes, it wraps
around and appears to be repeated within this space. The SMC correctly handles any valid
access to the memory device within the page (see Figure 15-3 on page 179).
A[23:0] is only significant for 8-bit memory, A[23:1] is used for 16-bit memory23.
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Figure 15-3.
Memory Connections for Six External Devices
NCS[0] - NCS[5]
NRD
SMC
NWE
NCS5
A[AD_MSB:0]
NCS4
D[15:0]
NCS3
NCS2
NCS1
NCS0
Memory Enable
Memory Enable
Memory Enable
Memory Enable
Memory Enable
Memory Enable
Output Enable
Write Enable
8 or 16
15.6.3
15.6.3.1
A[AD_MSB:0]
D[15:0] or D[7:0]
Connection to External Devices
Data bus width
A data bus width of 8 or 16 bits can be selected for each chip select. This option is controlled by
the Data Bus Width field in the Mode Register (MODE.DBW) for the corresponding chip select.
Figure 15-4 on page 179 shows how to connect a 512K x 8-bit memory on NCS2. Figure 15-5 on
page 180 shows how to connect a 512K x 16-bit memory on NCS2.
15.6.3.2
Byte write or byte select access
Each chip select with a 16-bit data bus can operate with one of two different types of write
access: byte write or byte select access. This is controlled by the Byte Access Type bit in the
MODE register (MODE.BAT) for the corresponding chip select.
Figure 15-4.
Memory Connection for an 8-bit Data Bus
SMC
D[7:0]
D[7:0]
A[18:2]
A[18:2]
A0
A0
A1
A1
NWE
Write Enable
NRD
Output Enable
NCS[2]
Memory Enable
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Figure 15-5.
Memory Connection for a 16-bit Data Bus
D[15:0]
D[15:0]
A[19:2]
A[18:1]
A1
SMC
A[0]
NBS0
Low Byte Enable
NBS1
High Byte Enable
NWE
Write Enable
NRD
Output Enable
NCS[2]
Memory Enable
•Byte write access
The byte write access mode supports one byte write signal per byte of the data bus and a single
read signal.
Note that the SMC does not allow boot in byte write access mode.
• For 16-bit devices: the SMC provides NWR0 and NWR1 write signals for respectively byte0
(lower byte) and byte1 (upper byte) of a 16-bit bus. One single read signal (NRD) is provided.
The byte write access mode is used to connect two 8-bit devices as a 16-bit memory.
The byte write option is illustrated on Figure 15-6 on page 181.
•Byte select access
In this mode, read/write operations can be enabled/disabled at a byte level. One byte select line
per byte of the data bus is provided. One NRD and one NWE signal control read and write.
• For 16-bit devices: the SMC provides NBS0 and NBS1 selection signals for respectively
byte0 (lower byte) and byte1 (upper byte) of a 16-bit bus. The byte select access is used to
connect one 16-bit device.
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Figure 15-6.
Connection of two 8-bit Devices on a 16-bit Bus: Byte Write Option
D[7:0]
D[7:0]
D[15:8]
A[24:2]
SMC
A[23:1]
A[0]
A1
NWR0
Write Enable
NWR1
NRD
Read Enable
Memory Enable
NCS[3]
D[15:8]
A[23:1]
A[0]
Write Enable
Read Enable
Memory Enable
•Signal multiplexing
Depending on the MODE.BAT bit, only the write signals or the byte select signals are used. To
save I/Os at the external bus interface, control signals at the SMC interface are multiplexed.
For 16-bit devices, bit A0 of address is unused. When byte select option is selected, NWR1 is
unused. When byte write option is selected, NBS0 to NBS1 are unused.
Table 15-3.
SMC Multiplexed Signal Translation
Signal Name
Device Type
Byte Access Type (BAT)
8-bit Bus
1 x 16-bit
2 x 8-bit
Byte Select
Byte Write
NBS0_A0
NBS0
NWE_NWR0
NWE
NWR0
NBS1_NWR1
NBS1
NWR1
A1
A1
NBS2_NWR2_A1
15.6.4
16-bit Bus
1 x 8-bit
A0
NWE
A1
Standard Read and Write Protocols
In the following sections, the byte access type is not considered. Byte select lines (NBS0 to
NBS1) always have the same timing as the address bus (A). NWE represents either the NWE
signal in byte select access type or one of the byte write lines (NWR0 to NWR1) in byte write
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access type. NWR0 to NWR1 have the same timings and protocol as NWE. In the same way,
NCS represents one of the NCS[0..5] chip select lines.
15.6.4.1
Read waveforms
The read cycle is shown on Figure 15-7 on page 182.
The read cycle starts with the address setting on the memory address bus, i.e.:
{A[23:2], A1, A0} for 8-bit devices
{A[23:2], A1} for 16-bit devices
Figure 15-7. Standard Read Cycle
CLK_SMC
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
NRD
NCS
D[15:0]
NRDSETUP
NCSRDSETUP
NRDPULSE
NCSRDPULSE
NRDHOLD
NCSRDHOLD
NRDCYCLE
•NRD waveform
The NRD signal is characterized by a setup timing, a pulse width, and a hold timing.
1. NRDSETUP: the NRD setup time is defined as the setup of address before the NRD
falling edge.
2. NRDPULSE: the NRD pulse length is the time between NRD falling edge and NRD rising edge.
3. NRDHOLD: the NRD hold time is defined as the hold time of address after the NRD rising edge.
•NCS waveform
Similarly, the NCS signal can be divided into a setup time, pulse length and hold time.
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1. NCSRDSETUP: the NCS setup time is defined as the setup time of address before the
NCS falling edge.
2. NCSRDPULSE: the NCS pulse length is the time between NCS falling edge and NCS
rising edge.
3. NCSRDHOLD: the NCS hold time is defined as the hold time of address after the NCS
rising edge.
•Read cycle
The NRDCYCLE time is defined as the total duration of the read cycle, i.e., from the time where
address is set on the address bus to the point where address may change. The total read cycle
time is equal to:
NRDCYCLE = NRDSETUP + NRDPULSE + NRDHOLD
Similarly,
NRDCYCLE = NCSRDSETUP + NCSRDPULSE + NCSRDHOLD
All NRD and NCS timings are defined separately for each chip select as an integer number of
CLK_SMC cycles. To ensure that the NRD and NCS timings are coherent, the user must define
the total read cycle instead of the hold timing. NRDCYCLE implicitly defines the NRD hold time
and NCS hold time as:
NRDHOLD = NRDCYCLE – NRDSETUP – NRDPULSE
And,
NCSRDHOLD = NRDCYCLE – NCSRDSETUP – NCSRDPULSE
•Null delay setup and hold
If null setup and hold parameters are programmed for NRD and/or NCS, NRD and NCS remain
active continuously in case of consecutive read cycles in the same memory (see Figure 15-8 on
page 184).
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Figure 15-8. No Setup, No Hold on NRD, and NCS Read Signals
CLK_SMC
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
NRD
NCS
D[15:0]
NRDSETUP
NRDPULSE
NRDPULSE
NCSRDPULSE
NCSRDPULSE
NCSRDPULSE
NRDCYCLE
NRDCYCLE
NRDCYCLE
• Null Pulse
Programming null pulse is not permitted. Pulse must be at least written to one. A null value leads
to unpredictable behavior.
15.6.4.2
Read mode
As NCS and NRD waveforms are defined independently of one other, the SMC needs to know
when the read data is available on the data bus. The SMC does not compare NCS and NRD timi n g s t o k n o w w h i c h s ig n a l r i s e s f i r s t . T h e R e a d M o d e b it i n t h e M O D E r e g i s t e r
(MODE.READMODE) of the corresponding chip select indicates which signal of NRD and NCS
controls the read operation.
•Read is controlled by NRD (MODE.READMODE = 1)
Figure 15-9 on page 185 shows the waveforms of a read operation of a typical asynchronous
RAM. The read data is available tPACC after the falling edge of NRD, and turns to ‘Z’ after the rising edge of NRD. In this case, the MODE.READMODE bit must be written to one (read is
controlled by NRD), to indicate that data is available with the rising edge of NRD. The SMC samples the read data internally on the rising edge of CLK_SMC that generates the rising edge of
NRD, whatever the programmed waveform of NCS may be.
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Figure 15-9. READMODE = 1: Data Is Sampled by SMC Before the Rising Edge of NRD
CLK_SMC
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
NRD
NCS
tPACC
D[15:0]
Data Sampling
•Read is controlled by NCS (MODE.READMODE = 0)
Figure 15-10 on page 186 shows the typical read cycle of an LCD module. The read data is valid
tPACC after the falling edge of the NCS signal and remains valid until the rising edge of NCS. Data
must be sampled when NCS is raised. In that case, the MODE.READMODE bit must be written
to zero (read is controlled by NCS): the SMC internally samples the data on the rising edge of
CML_SMC that generates the rising edge of NCS, whatever the programmed waveform of NRD
may be.
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Figure 15-10. READMODE = 0: Data Is Sampled by SMC Before the Rising Edge of NCS
CLK_SMC
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
NRD
NCS
tPACC
D[15:0]
Data Sampling
15.6.4.3
Write waveforms
The write protocol is similar to the read protocol. It is depicted in Figure 15-11 on page 187. The
write cycle starts with the address setting on the memory address bus.
•NWE waveforms
The NWE signal is characterized by a setup timing, a pulse width and a hold timing.
1. NWESETUP: the NWE setup time is defined as the setup of address and data before
the NWE falling edge.
2. NWEPULSE: the NWE pulse length is the time between NWE falling edge and NWE
rising edge.
3. NWEHOLD: the NWE hold time is defined as the hold time of address and data after
the NWE rising edge.
The NWE waveforms apply to all byte-write lines in byte write access mode: NWR0 to NWR3.
15.6.4.4
NCS waveforms
The NCS signal waveforms in write operation are not the same that those applied in read operations, but are separately defined.
1. NCSWRSETUP: the NCS setup time is defined as the setup time of address before the
NCS falling edge.
2. NCSWRPULSE: the NCS pulse length is the time between NCS falling edge and NCS
rising edge;
3. NCSWRHOLD: the NCS hold time is defined as the hold time of address after the NCS
rising edge.
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Figure 15-11. Write Cycle
CLK_SMC
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
NWE
NCS
NWESETUP
NCSWRSETUP
NWEPULSE
NCSWRPULSE
NWEHOLD
NCSWRHOLD
NWECYCLE
•Write cycle
The write cycle time is defined as the total duration of the write cycle, that is, from the time where
address is set on the address bus to the point where address may change. The total write cycle
time is equal to:
NWECYCLE = NWESETUP + NWEPULSE + NWEHOLD
Similarly,
NWECYCLE = NCSWRSETUP + NCSWRPULSE + NCSWRHOLD
All NWE and NCS (write) timings are defined separately for each chip select as an integer number of CLK_SMC cycles. To ensure that the NWE and NCS timings are coherent, the user must
define the total write cycle instead of the hold timing. This implicitly defines the NWE hold time
and NCS (write) hold times as:
NWEHOLD = NWECYCLE – NWESETUP – NWEPULSE
And,
NCSWRHOLD = NWECYCLE – NCSWRSETUP – NCSWRPULSE
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•Null delay setup and hold
If null setup parameters are programmed for NWE and/or NCS, NWE and/or NCS remain active
continuously in case of consecutive write cycles in the same memory (see Figure 15-12 on page
188). However, for devices that perform write operations on the rising edge of NWE or NCS,
such as SRAM, either a setup or a hold must be programmed.
Figure 15-12. Null Setup and Hold Values of NCS and NWE in Write Cycle
CLK_SMC
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
NWE,
NWE0, NWE1
NCS
D[15:0]
NWESETUP
NWEPULSE
NWEPULSE
NCSWRSETUP
NCSWRPULSE
NCSWRPULSE
NWECYCLE
NWECYCLE
NWECYCLE
•Null pulse
Programming null pulse is not permitted. Pulse must be at least written to one. A null value leads
to unpredictable behavior.
15.6.4.5
Write mode
The Write Mode bit in the MODE register (MODE.WRITEMODE) of the corresponding chip
select indicates which signal controls the write operation.
•Write is controlled by NWE (MODE.WRITEMODE = 1)
Figure 15-13 on page 189 shows the waveforms of a write operation with MODE.WRITEMODE
equal to one. The data is put on the bus during the pulse and hold steps of the NWE signal. The
internal data buffers are turned out after the NWESETUP time, and until the end of the write
cycle, regardless of the programmed waveform on NCS.
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Figure 15-13. WRITEMODE = 1. The Write Operation Is Controlled by NWE
CLK_SMC
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
NWE,
NWR0, NWR1
NCS
D[15:0]
•Write is controlled by NCS (MODE.WRITEMODE = 0)
Figure 15-14 on page 189 shows the waveforms of a write operation with MODE.WRITEMODE
written to zero. The data is put on the bus during the pulse and hold steps of the NCS signal.
The internal data buffers are turned out after the NCSWRSETUP time, and until the end of the
write cycle, regardless of the programmed waveform on NWE.
Figure 15-14. WRITEMODE = 0. The Write Operation Is Controlled by NCS
CLK_SMC
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
NWE,
NWR0, NWR1
NCS
D[15:0]
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15.6.4.6
Coding timing parameters
All timing parameters are defined for one chip select and are grouped together in one register
according to their type.
The Setup register (SETUP) groups the definition of all setup parameters:
• NRDSETUP, NCSRDSETUP, NWESETUP, and NCSWRSETUP.
The Pulse register (PULSE) groups the definition of all pulse parameters:
• NRDPULSE, NCSRDPULSE, NWEPULSE, and NCSWRPULSE.
The Cycle register (CYCLE) groups the definition of all cycle parameters:
• NRDCYCLE, NWECYCLE.
Table 15-4 on page 190 shows how the timing parameters are coded and their permitted range.
Table 15-4.
Coding and Range of Timing Parameters
Permitted Range
Coded Value
Number of Bits
Effective Value
Coded Value
Effective Value
setup [5:0]
6
128 x setup[5] + setup[4:0]
0 ≤ value ≤ 31
32 ≤ value ≤ 63
0 ≤ value ≤ 31
128 ≤ value ≤ 128+31
pulse [6:0]
7
256 x pulse[6] + pulse[5:0]
0 ≤ value ≤ 63
64≤ value ≤ 127
0 ≤ value ≤ 63
256 ≤ value ≤ 256+63
256 x cycle[8:7] + cycle[6:0]
0 ≤ value ≤ 127
128 ≤ value ≤ 255
256 ≤ value ≤ 383
384 ≤ value ≤ 511
0 ≤ value ≤ 127
256 ≤ value ≤ 256+127
512 ≤ value ≤ 512+127
768 ≤ value ≤ 768+127
cycle [8:0]
15.6.4.7
9
Usage restriction
The SMC does not check the validity of the user-programmed parameters. If the sum of SETUP
and PULSE parameters is larger than the corresponding CYCLE parameter, this leads to unpredictable behavior of the SMC.
For read operations:
Null but positive setup and hold of address and NRD and/or NCS can not be guaranteed at the
memory interface because of the propagation delay of theses signals through external logic and
pads. If positive setup and hold values must be verified, then it is strictly recommended to program non-null values so as to cover possible skews between address, NCS and NRD signals.
For write operations:
If a null hold value is programmed on NWE, the SMC can guarantee a positive hold of address,
byte select lines, and NCS signal after the rising edge of NWE. This is true if the MODE.WRITEMODE bit is written to one. See Section 15.6.5.2.
For read and write operations: a null value for pulse parameters is forbidden and may lead to
unpredictable behavior.
In read and write cycles, the setup and hold time parameters are defined in reference to the
address bus. For external devices that require setup and hold time between NCS and NRD signals (read), or between NCS and NWE signals (write), these setup and hold times must be
converted into setup and hold times in reference to the address bus.
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15.6.5
15.6.5.1
Automatic Wait States
Under certain circumstances, the SMC automatically inserts idle cycles between accesses to
avoid bus contention or operation conflict.
Chip select wait states
The SMC always inserts an idle cycle between two transfers on separate chip selects. This idle
cycle ensures that there is no bus contention between the deactivation of one device and the
activation of the next one.
During chip select wait state, all control lines are turned inactive: NBS0 to NBS3, NWR0 to
NWR3, NCS[0..5], NRD lines are all set to high level.
Figure 15-15 on page 191 illustrates a chip select wait state between access on Chip Select 0
(NCS0) and Chip Select 2 (NCS2).
Figure 15-15. Chip Select Wait State Between a Read Access on NCS0 and a Write Access on
NCS2
CLK_SMC
_MSB:2]
, NBS1,
, A1
NRD
NWE
NCS0
NCS2
NWECYCLE
NRDCYCLE
D[15:0]
Read to Write
Wait State
15.6.5.2
Chip Select
Wait State
Early read wait state
In some cases, the SMC inserts a wait state cycle between a write access and a read access to
allow time for the write cycle to end before the subsequent read cycle begins. This wait state is
not generated in addition to a chip select wait state. The early read cycle thus only occurs
between a write and read access to the same memory device (same chip select).
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An early read wait state is automatically inserted if at least one of the following conditions is
valid:
• if the write controlling signal has no hold time and the read controlling signal has no setup
time (Figure 15-16 on page 192).
• in NCS write controlled mode (MODE.WRITEMODE = 0), if there is no hold timing on the
NCS signal and the NCSRDSETUP parameter is set to zero, regardless of the read mode
(Figure 15-17 on page 193). The write operation must end with a NCS rising edge. Without
an early read wait state, the write operation could not complete properly.
• in NWE controlled mode (MODE.WRITEMODE = 1) and if there is no hold timing
(NWEHOLD = 0), the feedback of the write control signal is used to control address, data,
chip select, and byte select lines. If the external write control signal is not inactivated as
expected due to load capacitances, an early read wait state is inserted and address, data
and control signals are maintained one more cycle. See Figure 15-18 on page 194.
Figure 15-16. Early Read Wait State: Write with No Hold Followed by Read with No Setup.
CLK_SMC
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
NWE
NRD
No hold
No setup
D[15:0]
Write cycle
Early Read
Wait state
Read cycle
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Figure 15-17. Early Read Wait State: NCS Controlled Write with No Hold Followed by a Read
with No Setup.
CLK_SMC
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
NWE
NRD
No hold
No setup
D[15:0]
Write cycle
(WRITEMODE=0)
Read cycle
Early Read
Wait State (READMODE=0 or READMODE=1)
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Figure 15-18. Early Read Wait State: NWE-controlled Write with No Hold Followed by a Read
with one Set-up Cycle.
CLK_SMC
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
Internal write controlling signal
external write controlling
signal(NWE)
No hold
Read setup=1
NRD
D[15:0]
Write cycle
(WRITEMODE = 1)
15.6.5.3
Early Read
Wait State
Read cycle
(READMODE=0 or READMODE=1)
Reload user configuration wait state
The user may change any of the configuration parameters by writing the SMC user interface.
When detecting that a new user configuration has been written in the user interface, the SMC
inserts a wait state before starting the next access. The so called “reload user configuration wait
state” is used by the SMC to load the new set of parameters to apply to next accesses.
The reload configuration wait state is not applied in addition to the chip select wait state. If
accesses before and after reprogramming the user interface are made to different devices (different chip selects), then one single chip select wait state is applied.
On the other hand, if accesses before and after writing the user interface are made to the same
device, a reload configuration wait state is inserted, even if the change does not concern the current chip select.
•User procedure
To insert a reload configuration wait state, the SMC detects a write access to any MODE register
of the user interface. If the user only modifies timing registers (SETUP, PULSE, CYCLE registers) in the user interface, he must validate the modification by writing the MODE register, even
if no change was made on the mode parameters.
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•Slow clock mode transition
A reload configuration wait state is also inserted when the slow clock mode is entered or exited,
after the end of the current transfer (see Section 15.6.8).
15.6.5.4
Read to write wait state
Due to an internal mechanism, a wait cycle is always inserted between consecutive read and
write SMC accesses.
This wait cycle is referred to as a read to write wait state in this document.
This wait cycle is applied in addition to chip select and reload user configuration wait states
when they are to be inserted. See Figure 15-15 on page 191.
15.6.6
Data Float Wait States
Some memory devices are slow to release the external bus. For such devices, it is necessary to
add wait states (data float wait states) after a read access:
• before starting a read access to a different external memory.
• before starting a write access to the same device or to a different external one.
The Data Float Output Time (tDF) for each external memory device is programmed in the Data
Float Time field of the MODE register (MODE.TDFCYCLES) for the corresponding chip select.
The value of MODE.TDFCYCLES indicates the number of data float wait cycles (between 0 and
15) before the external device releases the bus, and represents the time allowed for the data
output to go to high impedance after the memory is disabled.
Data float wait states do not delay internal memory accesses. Hence, a single access to an
external memory with long t DF will not slow down the execution of a program from internal
memory.
The data float wait states management depends on the MODE.READMODE bit and the TDF
Optimization bit of the MODE register (MODE.TDFMODE) for the corresponding chip select.
15.6.6.1
Read mode
Writing a one to the MODE.READMODE bit indicates to the SMC that the NRD signal is responsible for turning off the tri-state buffers of the external memory device. The data float period then
begins after the rising edge of the NRD signal and lasts MODE.TDFCYCLES cycles of the
CLK_SMC clock.
When the read operation is controlled by the NCS signal (MODE.READMODE = 0), the
MODE.TDFCYCLES field gives the number of CLK_SMC cycles during which the data bus
remains busy after the rising edge of NCS.
Figure 15-19 on page 196 illustrates the data float period in NRD-controlled mode
(MODE.READMODE =1), assuming a data float period of two cycles (MODE.TDFCYCLES = 2).
Figure 15-20 on page 196 shows the read operation when controlled by NCS (MODE.READMODE = 0) and the MODE.TDFCYCLES field equals to three.
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Figure 15-19. TDF Period in NRD Controlled Read Access (TDFCYCLES = 2)
CLK_SMC
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
NRD
NCS
D[15:0]
tPACC
TDF = 2 clock cycles
NRD controlled read operation
Figure 15-20. TDF Period in NCS Controlled Read Operation (TDFCYCLES = 3)
CLK_SMC
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
NRD
NCS
D[15:0]
tPACC
TDF = 3 clock cycles
NCS controlled read operation
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15.6.6.2
TDF optimization enabled (MODE.TDFMODE = 1)
When the MODE.TDFMODE bit is written to one (TDF optimization is enabled), the SMC takes
advantage of the setup period of the next access to optimize the number of wait states cycle to
insert.
Figure 15-21 on page 197 shows a read access controlled by NRD, followed by a write access
controlled by NWE, on Chip Select 0. Chip Select 0 has been programmed with:
NRDHOLD = 4; READMODE = 1 (NRD controlled)
NWESETUP = 3; WRITEMODE = 1 (NWE controlled)
TDFCYCLES = 6; TDFMODE = 1 (optimization enabled).
Figure 15-21. TDF Optimization: No TDF Wait States Are Inserted if the TDF Period Is over when the Next Access Begins
CLK_SMC
A[AD_MSB:2]
NRD
NRDHOLD = 4
NWE
NWESETUP = 3
NCS0
TDFCYCLES = 6
D[15:0]
Read access on NCS0 (NRD controlled)
15.6.6.3
Read to Write
Wait State
Write access on NCS0 (NWE controlled)
TDF optimization disabled (MODE.TDFMODE = 0)
When optimization is disabled, data float wait states are inserted at the end of the read transfer,
so that the data float period is ended when the second access begins. If the hold period of the
read1 controlling signal overlaps the data float period, no additional data float wait states will be
inserted.
Figure 15-22 on page 198, Figure 15-23 on page 198 and Figure 15-24 on page 199 illustrate
the cases:
• read access followed by a read access on another chip select.
• read access followed by a write access on another chip select.
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• read access followed by a write access on the same chip select.
with no TDF optimization.
Figure 15-22. TDF Optimization Disabled (MODE.TDFMODE = 0). TDF Wait States between Two Read Accesses on Different Chip Selects.
CLK_SMC
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
Read1 controlling
signal(NRD)
Read1 hold = 1
Read2 controlling
signal(NRD)
Read2 setup = 1
TDFCYCLES = 6
D[15:0]
5 TDF WAIT STATES
Read 2 cycle
TDFMODE=0
(optimization disabled)
Read1 cycle
TDFCYCLES = 6
Chip Select Wait State
Figure 15-23. TDF Optimization Disabled (MODE.TDFMODE= 0). TDF Wait States between a Read and a Write Access
on Different Chip Selects.
CLK_SMC
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
Read1 controlling
signal(NRD)
Write2 setup = 1
Read1 hold = 1
Write2 controlling
signal(NWE)
TDFCYCLES = 4
D[15:0]
Read1 cycle
TDFCYCLES = 4
2 TDF WAIT STATES
Read to Write Chip Select
Wait State Wait State
Write 2 cycle
TDFMODE=0
(optimization disabled)
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Figure 15-24. TDF Optimization Disabled (MODE.TDFMODE = 0). TDF Wait States between Read and Write accesses on
the Same Chip Select.
CLK_SMC
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
Read1 controlling
signal(NRD)
Write2 setup = 1
Read1 hold = 1
Write2 controlling
signal(NWE)
TDFCYCLES = 5
D[15:0]
4 TDF WAIT STATES
Read1 cycle
TDFCYCLES = 5
15.6.7
Read to Write
Wait State
Write 2 cycle
TDFMODE=0
(optimization disabled)
External Wait
Any access can be extended by an external device using the NWAIT input signal of the SMC.
The External Wait Mode field of the MODE register (MODE.EXNWMODE) on the corresponding
chip select must be written to either two (frozen mode) or three (ready mode). When the
MODE.EXNWMODE field is written to zero (disabled), the NWAIT signal is simply ignored on
the corresponding chip select. The NWAIT signal delays the read or write operation in regards to
the read or write controlling signal, depending on the read and write modes of the corresponding
chip select.
15.6.7.1
Restriction
When one of the MODE.EXNWMODE is enabled, it is mandatory to program at least one hold
cycle for the read/write controlling signal. For that reason, the NWAIT signal cannot be used in
Page Mode (Section 15.6.9), or in Slow Clock Mode (Section 15.6.8).
The NWAIT signal is assumed to be a response of the external device to the read/write request
of the SMC. Then NWAIT is examined by the SMC only in the pulse state of the read or write
controlling signal. The assertion of the NWAIT signal outside the expected period has no impact
on SMC behavior.
15.6.7.2
Frozen mode
When the external device asserts the NWAIT signal (active low), and after internal synchronization of this signal, the SMC state is frozen, i.e., SMC internal counters are frozen, and all control
signals remain unchanged. When the synchronized NWAIT signal is deasserted, the SMC completes the access, resuming the access from the point where it was stopped. See Figure 15-25
on page 200. This mode must be selected when the external device uses the NWAIT signal to
delay the access and to freeze the SMC.
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The assertion of the NWAIT signal outside the expected period is ignored as illustrated in Figure
15-26 on page 201.
Figure 15-25. Write Access with NWAIT Assertion in Frozen Mode (MODE.EXNWMODE = 2).
CLK_SMC
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
FROZEN STATE
4
3
2
1
1
1
1
3
2
2
2
2
0
NWE
6
5
4
0
NCS
D[15:0]
NWAIT
Internally synchronized
NWAIT signal
Write cycle
EXNWMODE = 2 (Frozen)
WRITEMODE = 1 (NWE controlled)
NWEPULSE = 5
NCSWRPULSE = 7
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Figure 15-26. Read Access with NWAIT Assertion in Frozen Mode (MODE.EXNWMODE = 2).
CLK_SMC
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
FROZEN STATE
NCS
4
1
NRD
3
2
2
2
1
0
2
1
0
2
1
0
0
5
5
5
4
3
NWAIT
Internally synchronized
NWAIT signal
Read cycle
EXNWMODE = 2 (Frozen)
READMODE = 0 (NCS controlled)
NRDPULSE = 2, NRDHOLD = 6
NCSRDPULSE = 5, NCSRDHOLD = 3
Assertion is ignored
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15.6.7.3
Ready mode
In Ready mode (MODE.EXNWMODE = 3), the SMC behaves differently. Normally, the SMC
begins the access by down counting the setup and pulse counters of the read/write controlling
signal. In the last cycle of the pulse phase, the resynchronized NWAIT signal is examined.
If asserted, the SMC suspends the access as shown in Figure 15-27 on page 202 and Figure
15-28 on page 203. After deassertion, the access is completed: the hold step of the access is
performed.
This mode must be selected when the external device uses deassertion of the NWAIT signal to
indicate its ability to complete the read or write operation.
If the NWAIT signal is deasserted before the end of the pulse, or asserted after the end of the
pulse of the controlling read/write signal, it has no impact on the access length as shown in Figure 15-28 on page 203.
Figure 15-27. NWAIT Assertion in Write Access: Ready Mode (MODE.EXNWMODE = 3).
C LK_SM C
A [A D _ M S B :2 ]
N BS 0, NBS 1,
A 0, A1
FROZEN STATE
4
3
2
1
0
2
1
0
0
NW E
6
5
4
3
1
1
0
NCS
D [1 5 :0 ]
N W A IT
In te rn a lly syn ch ro n ize d
N W A IT s ig n a l
W rite cyc le
E X N W M O D E = 3 (R e a d y m o d e )
W R IT E M O D E = 1 (N W E _ co n tro lle d )
N W EPU LSE = 5
N CSW RPU LSE = 7
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Figure 15-28. NWAIT Assertion in Read Access: Ready Mode (EXNWMODE = 3).
CLK_SMC
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
Wait STATE
NCS
NRD
6
5
4
3
2
6
5
4
3
1
2
0
0
1
1
0
NWAIT
Internally synchronized
NWAIT signal
Read cycle
Assertion is ignored
EXNWMODE = 3 (Ready mode)
READMODE = 0 (NCS_controlled)
NRDPULSE = 7
NCSRDPULSE = 7
Assertion is ignored
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15.6.7.4
NWAIT latency and read/write timings
There may be a latency between the assertion of the read/write controlling signal and the assertion of the NWAIT signal by the device. The programmed pulse length of the read/write
controlling signal must be at least equal to this latency plus the two cycles of resynchronization
plus one cycle. Otherwise, the SMC may enter the hold state of the access without detecting the
NWAIT signal assertion. This is true in frozen mode as well as in ready mode. This is illustrated
on Figure 15-29 on page 204.
When the MODE.EXNWMODE field is enabled (ready or frozen), the user must program a pulse
length of the read and write controlling signal of at least:
minimal pulse length = NWAIT latency + 2 synchronization cycles + 1 cycle
Figure 15-29. NWAIT Latency
CLK_SMC
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
Wait STATE
4
3
2
1
0
0
0
NRD
Minimal pulse length
NWAIT
nternally synchronized
NWAIT signal
NWAIT latency 2 cycle resynchronization
Read cycle
EXNWMODE = 2 or 3
READMODE = 1 (NRD controlled)
NRDPULSE = 5
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15.6.8
Slow Clock Mode
The SMC is able to automatically apply a set of “slow clock mode” read/write waveforms when
an internal signal driven by the SMC’s Power Management Controller is asserted because
CLK_SMC has been turned to a very slow clock rate (typically 32 kHz clock rate). In this mode,
the user-programmed waveforms are ignored and the slow clock mode waveforms are applied.
This mode is provided so as to avoid reprogramming the User Interface with appropriate waveforms at very slow clock rate. When activated, the slow mode is active on all chip selects.
15.6.8.1
Slow clock mode waveforms
Figure 15-30 on page 205 illustrates the read and write operations in slow clock mode. They are
valid on all chip selects. Table 15-5 on page 205 indicates the value of read and write parameters in slow clock mode.
Figure 15-30. Read and Write Cycles in Slow Clock Mode
CLK_SMC
CLK_SMC
A[AD_MSB:2]
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
NWE
NBS0, NBS1,
A0, A1
1
NRD
1
1
1
1
NCS
NCS
NRDCYCLES = 2
NWECYCLES = 3
SLOW CLOCK MODE WRITE
Table 15-5.
SLOW CLOCK MODE READ
Read and Write Timing Parameters in Slow Clock Mode
Read Parameters
Duration (cycles)
Write Parameters
Duration (cycles)
NRDSETUP
1
NWESETUP
1
NRDPULSE
1
NWEPULSE
1
NCSRDSETUP
0
NCSWRSETUP
0
NCSRDPULSE
2
NCSWRPULSE
3
NRDCYCLE
2
NWECYCLE
3
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15.6.8.2
Switching from (to) slow clock mode to (from) normal mode
When switching from slow clock mode to the normal mode, the current slow clock mode transfer
is completed at high clock rate, with the set of slow clock mode parameters. See Figure 15-31
on page 206. The external device may not be fast enough to support such timings.
Figure 15-32 on page 207 illustrates the recommended procedure to properly switch from one
mode to the other.
Figure 15-31. Clock Rate Transition Occurs while the SMC is Performing a Write Operation
Slow Clock Mode
Internal signal from PM
CLK_SMC
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
NWE
1
1
1
1
1
1
2
3
2
NCS
NWECYCLE = 3
NWECYCLE = 7
SLOW CLOCK MODE WRITE SLOW CLOCK MODE WRITE
This write cycle finishes with the slow clock mode set
of parameters after the clock rate transition
NORMAL MODE WRITE
Slow clock mode transition is detected:
Reload Configuration Wait State
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Figure 15-32. Recommended Procedure to Switch from Slow Clock Mode to Normal Mode or from Normal Mode to Slow
Clock Mode
Slow Clock Mode
Internal signal from PM
CLK_SMC
A[AD_MSB:2]
NBS0, NBS1,
A0, A1
NWE
1
1
1
2
3
2
NCS
SLOW CLOCK MODE WRITE
NORMAL MODE WRITE
IDLE STATE
Reload Configuration
Wait State
15.6.9
Asynchronous Page Mode
The SMC supports asynchronous burst reads in page mode, providing that the Page Mode
Enabled bit is written to one in the MODE register (MODE.PMEN). The page size must be configured in the Page Size field in the MODE register (MODE.PS) to 4, 8, 16, or 32 bytes.
The page defines a set of consecutive bytes into memory. A 4-byte page (resp. 8-, 16-, 32-byte
page) is always aligned to 4-byte boundaries (resp. 8-, 16-, 32-byte boundaries) of memory. The
MSB of data address defines the address of the page in memory, the LSB of address define the
address of the data in the page as detailed in Table 15-6 on page 207.
With page mode memory devices, the first access to one page (tpa) takes longer than the subsequent accesses to the page (tsa) as shown in Figure 15-33 on page 208. When in page mode,
the SMC enables the user to define different read timings for the first access within one page,
and next accesses within the page.
Table 15-6.
Page Address and Data Address within a Page
Page Size
Page Address(1)
Data Address in the Page(2)
4 bytes
A[23:2]
A[1:0]
8 bytes
A[23:3]
A[2:0]
16 bytes
A[23:4]
A[3:0]
32 bytes
A[23:5]
A[4:0]
Notes:
1. A denotes the address bus of the memory device
2. For 16-bit devices, the bit 0 of address is ignored.
15.6.9.1
Protocol and timings in page mode
Figure 15-33 on page 208 shows the NRD and NCS timings in page mode access.
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Figure 15-33. Page Mode Read Protocol (Address MSB and LSB Are Defined in Table 15-6 on page 207)
CLK_SMC
A[MSB]
A[LSB]
NRD
tpa
tsa
NCS
tsa
D[15:0]
NCSRDPULSE
NRDPULSE
NRDPULSE
The NRD and NCS signals are held low during all read transfers, whatever the programmed values of the setup and hold timings in the User Interface may be. Moreover, the NRD and NCS
timings are identical. The pulse length of the first access to the page is defined with the
PULSE.NCSRDPULSE field value. The pulse length of subsequent accesses within the page
are defined using the PULSE.NRDPULSE field value.
In page mode, the programming of the read timings is described in Table 15-7 on page 208:
Table 15-7.
Programming of Read Timings in Page Mode
Parameter
Value
Definition
READMODE
‘x’
No impact
NCSRDSETUP
‘x’
No impact
NCSRDPULSE
tpa
Access time of first access to the page
NRDSETUP
‘x’
No impact
NRDPULSE
tsa
Access time of subsequent accesses in the page
NRDCYCLE
‘x’
No impact
The SMC does not check the coherency of timings. It will always apply the NCSRDPULSE timings as page access timing (tpa) and the NRDPULSE for accesses to the page (tsa), even if the
programmed value for tpa is shorter than the programmed value for tsa.
15.6.9.2
Byte access type in page mode
The byte access type configuration remains active in page mode. For 16-bit or 32-bit page mode
devices that require byte selection signals, configure the MODE.BAT bit to zero (byte select
access type).
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15.6.9.3
Page mode restriction
The page mode is not compatible with the use of the NWAIT signal. Using the page mode and
the NWAIT signal may lead to unpredictable behavior.
15.6.9.4
Sequential and non-sequential accesses
If the chip select and the MSB of addresses as defined in Table 15-6 on page 207 are identical,
then the current access lies in the same page as the previous one, and no page break occurs.
Using this information, all data within the same page, sequential or not sequential, are accessed
with a minimum access time (tsa). Figure 15-34 on page 209 illustrates access to an 8-bit memory device in page mode, with 8-byte pages. Access to D1 causes a page access with a long
access time (tpa). Accesses to D3 and D7, though they are not sequential accesses, only require
a short access time (tsa).
If the MSB of addresses are different, the SMC performs the access of a new page. In the same
way, if the chip select is different from the previous access, a page break occurs. If two sequential accesses are made to the page mode memory, but separated by an other internal or external
peripheral access, a page break occurs on the second access because the chip select of the
device was deasserted between both accesses.
Figure 15-34. Access to Non-sequential Data within the Same Page
CLK_SMC
Page address
A[AD_MSB:3]
A[2], A1, A0
A1
A3
A7
NRD
NCS
D[7:0]
D1
NCSRDPULSE
D3
NRDPULSE
D7
NRDPULSE
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15.7
User Interface
The SMC is programmed using the registers listed in Table 15-8 on page 210. For each chip select, a set of four registers
is used to program the parameters of the external device connected on it. In Table 15-8 on page 210, “CS_number”
denotes the chip select number. Sixteen bytes (0x10) are required per chip select.
The user must complete writing the configuration by writing anyone of the Mode Registers.
Table 15-8.
SMC Register Memory Map
Offset
Register
Register Name
Access
Reset
0x00 + CS_number*0x10
Setup Register
SETUP
Read/Write
0x01010101
0x04 + CS_number*0x10
Pulse Register
PULSE
Read/Write
0x01010101
0x08 + CS_number*0x10
Cycle Register
CYCLE
Read/Write
0x00030003
0x0C + CS_number*0x10
Mode Register
MODE
Read/Write
0x10002103
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15.7.1
Setup Register
Register Name:
SETUP
Access Type:
Read/Write
Offset:
0x00 + CS_number*0x10
Reset Value:
0x01010101
31
30
–
–
23
22
–
–
15
14
–
–
7
6
–
–
29
28
27
26
25
24
18
17
16
10
9
8
1
0
NCSRDSETUP
21
20
19
NRDSETUP
13
12
11
NCSWRSETUP
5
4
3
2
NWESETUP
• NCSRDSETUP: NCS Setup Length in READ Access
In read access, the NCS signal setup length is defined as:
NCS Setup Length in read access = ( 128 × NCSRDSETUP [ 5 ] + NCSRDSETUP [ 4:0 ] ) clock cycles
• NRDSETUP: NRD Setup Length
The NRD signal setup length is defined in clock cycles as:
NRD Setup Length = ( 128 × NRDSETUP [ 5 ] + NRDSETUP [ 4:0 ] ) clock cycles
• NCSWRSETUP: NCS Setup Length in WRITE Access
In write access, the NCS signal setup length is defined as:
NCS Setup Length in write access = ( 128 × NCSWRSETUP [ 5 ] + NCSWRSETUP [ 4:0 ] ) clock cycles
• NWESETUP: NWE Setup Length
The NWE signal setup length is defined as:
NWE Setup Length = ( 128 × NWESETUP [ 5 ] + NWESETUP [ 4:0 ] ) clock cycles
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15.7.2
Pulse Register
Register Name:
PULSE
Access Type:
Read/Write
Offset:
0x04 + CS_number*0x10
Reset Value:
0x01010101
31
30
29
28
27
26
25
24
18
17
16
10
9
8
2
1
0
NCSRDPULSE
–
23
22
21
20
19
NRDPULSE
–
15
14
13
12
11
NCSWRPULSE
–
7
6
5
4
3
NWEPULSE
–
• NCSRDPULSE: NCS Pulse Length in READ Access
In standard read access, the NCS signal pulse length is defined as:
NCS Pulse Length in read access = ( 256 × NCSRDPULSE [ 6 ] + NCSRDPULSE [ 5:0 ] ) clock cycles
The NCS pulse length must be at least one clock cycle.
In page mode read access, the NCSRDPULSE field defines the duration of the first access to one page.
• NRDPULSE: NRD Pulse Length
In standard read access, the NRD signal pulse length is defined in clock cycles as:
NRD Pulse Length = ( 256 × NRDPULSE [ 6 ] + NRDPULSE [ 5:0 ] ) clock cycles
The NRD pulse length must be at least one clock cycle.
In page mode read access, the NRDPULSE field defines the duration of the subsequent accesses in the page.
• NCSWRPULSE: NCS Pulse Length in WRITE Access
In write access, the NCS signal pulse length is defined as:
NCS Pulse Length in write access = ( 256 × NCSWRPULSE [ 6 ] + NCSWRPULSE [ 5:0 ] ) clock cycles
The NCS pulse length must be at least one clock cycle.
• NWEPULSE: NWE Pulse Length
The NWE signal pulse length is defined as:
NWE Pulse Length = ( 256 × NWEPULSE [ 6 ] + NWEPULSE [ 5:0 ] ) clock cycles
The NWE pulse length must be at least one clock cycle.
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15.7.3
Cycle Register
Register Name:
CYCLE
Access Type:
Read/Write
Offset:
0x08 + CS_number*0x10
Reset Value:
0x00030003
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
NRDCYCLE[8]
23
22
21
20
19
18
17
16
NRDCYCLE[7:0]
15
14
13
12
11
10
9
8
–
–
–
–
–
–
–
NWECYCLE[8]
7
6
5
4
3
2
1
0
NWECYCLE[7:0]
• NRDCYCLE[8:0]: Total Read Cycle Length
The total read cycle length is the total duration in clock cycles of the read cycle. It is equal to the sum of the setup, pulse and
hold steps of the NRD and NCS signals. It is defined as:
Read Cycle Length = ( 256 × NRDCYCLE [ 8:7 ] + NRDCYCLE [ 6:0 ] ) clock cycles
• NWECYCLE[8:0]: Total Write Cycle Length
The total write cycle length is the total duration in clock cycles of the write cycle. It is equal to the sum of the setup, pulse and
hold steps of the NWE and NCS signals. It is defined as:
Write Cycle Length = ( 256 × NWECYCLE [ 8:7 ] + NWECYCLE [ 6:0 ] ) clock cycles
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15.7.4
Mode Register
Register Name:
MODE
Access Type:
Read/Write
Offset:
0x0C + CS_number*0x10
Reset Value:
0x10002103
31
30
29
28
–
–
23
22
21
20
–
–
–
TDFMODE
15
14
13
12
–
–
7
6
–
–
PS
DBW
5
4
EXNWMODE
27
26
25
24
–
–
–
PMEN
19
18
17
16
TDFCYCLES
11
10
9
8
–
–
–
BAT
3
2
1
0
–
–
WRITEMODE
READMODE
• PS: Page Size
If page mode is enabled, this field indicates the size of the page in bytes.
PS
Page Size
0
4-byte page
1
8-byte page
2
16-byte page
3
32-byte page
• PMEN: Page Mode Enabled
1: Asynchronous burst read in page mode is applied on the corresponding chip select.
0: Standard read is applied.
• TDFMODE: TDF Optimization
1: TDF optimization is enabled. The number of TDF wait states is optimized using the setup period of the next read/write
access.
0: TDF optimization is disabled.The number of TDF wait states is inserted before the next access begins.
• TDFCYCLES: Data Float Time
This field gives the integer number of clock cycles required by the external device to release the data after the rising edge of the
read controlling signal. The SMC always provide one full cycle of bus turnaround after the TDFCYCLES period. The external
bus cannot be used by another chip select during TDFCYCLES plus one cycles. From 0 up to 15 TDFCYCLES can be set.
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• DBW: Data Bus Width
DBW
Data Bus Width
0
8-bit bus
1
16-bit bus
2
Reserved
3
Reserved
• BAT: Byte Access Type
This field is used only if DBW defines a 16-bit data bus.
BAT
Byte Access Type
0
Byte select access type:
Write operation is controlled using NCS, NWE, NBS0, NBS1
Read operation is controlled using NCS, NRD, NBS0, NBS1
1
Byte write access type:
Write operation is controlled using NCS, NWR0, NWR1
Read operation is controlled using NCS and NRD
• EXNWMODE: External WAIT Mode
The NWAIT signal is used to extend the current read or write signal. It is only taken into account during the pulse phase of the
read and write controlling signal. When the use of NWAIT is enabled, at least one cycle hold duration must be programmed for
the read and write controlling signal.
EXNWMODE
External NWAIT Mode
0
Disabled:
the NWAIT input signal is ignored on the corresponding chip select.
1
Reserved
2
Frozen Mode:
if asserted, the NWAIT signal freezes the current read or write cycle. after deassertion, the read or write cycle
is resumed from the point where it was stopped.
3
Ready Mode:
the NWAIT signal indicates the availability of the external device at the end of the pulse of the controlling read
or write signal, to complete the access. If high, the access normally completes. If low, the access is extended
until NWAIT returns high.
• WRITEMODE: Write Mode
1: The write operation is controlled by the NWE signal. If TDF optimization is enabled (TDFMODE =1), TDF wait states will be
inserted after the setup of NWE.
0: The write operation is controlled by the NCS signal. If TDF optimization is enabled (TDFMODE =1), TDF wait states will be
inserted after the setup of NCS.
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• READMODE: Read Mode
READMODE
Read Access Mode
0
The read operation is controlled by the NCS signal.
If TDF are programmed, the external bus is marked busy after the rising edge of NCS.
If TDF optimization is enabled (TDFMODE = 1), TDF wait states are inserted after the setup of NCS.
1
The read operation is controlled by the NRD signal.
If TDF cycles are programmed, the external bus is marked busy after the rising edge of NRD.
If TDF optimization is enabled (TDFMODE =1), TDF wait states are inserted after the setup of NRD.
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16. SDRAM Controller (SDRAMC)
Rev: 2.2.0.3
16.1
Features
• 128-Mbytes address space
• Numerous configurations supported
•
•
•
•
•
•
16.2
– 2K, 4K, 8K row address memory parts
– SDRAM with two or four internal banks
– SDRAM with 16-bit data path
Programming facilities
– Word, halfword, byte access
– Automatic page break when memory boundary has been reached
– Multibank ping-pong access
– Timing parameters specified by software
– Automatic refresh operation, refresh rate is programmable
– Automatic update of DS, TCR and PASR parameters (mobile SDRAM devices)
Energy-saving capabilities
– Self-refresh, power-down, and deep power-down modes supported
– Supports mobile SDRAM devices
Error detection
– Refresh error interrupt
SDRAM power-up initialization by software
CAS latency of one, two, and three supported
Auto Precharge command not used
Overview
The SDRAM Controller (SDRAMC) extends the memory capabilities of a chip by providing the
interface to an external 16-bit SDRAM device. The page size supports ranges from 2048 to 8192
and the number of columns from 256 to 2048. It supports byte (8-bit) and halfword (16-bit)
accesses.
The SDRAMC supports a read or write burst length of one location. It keeps track of the active
row in each bank, thus maximizing SDRAM performance, e.g., the application may be placed in
one bank and data in the other banks. So as to optimize performance, it is advisable to avoid
accessing different rows in the same bank.
The SDRAMC supports a CAS latency of one, two, or three and optimizes the read access
depending on the frequency.
The different modes available (self refresh, power-down, and deep power-down modes) minimize power consumption on the SDRAM device.
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16.3
Block Diagram
Figure 16-1. SDRAM Controller Block Diagram
SDCK
SDCK
SDCKE
SDRAM C
C hip S elect
SDCKE
SDCS
M em ory
C ontroller
SDCS
B A [1:0]
SDRAM C
Interrupt
A D D R [17 :16]
RAS
RAS
CAS
CAS
SDW E
P ow er
M anager
SDW E
SDRAMC
C LK _S D R A M C
D Q M [0]
EBI
M U X Logic
I/O
C ontroller
A D D R [0 ]
D Q M [1]
NW E1
S D R A M C _A [9 :0]
A D D R [11:2]
S D R A M C _ A [10 ]
S D A 10
S D R A M C _ A [12 :11]
U ser Interface
A D D R [13 :14 ]
D [15:0]
D A T A [15 :0]
P eripheral B us
16.4
I/O Lines Description
Table 16-1.
I/O Lines Description
Name
Description
Type
Active Level
SDCK
SDRAM Clock
Output
SDCKE
SDRAM Clock Enable
Output
BA[1:0]
Bank Select Signals
Output
RAS
Row Signal
Output
Low
CAS
Column Signal
Output
Low
SDWE
SDRAM Write Enable
Output
Low
High
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Table 16-1.
16.5
16.5.1
I/O Lines Description
Name
Description
Type
Active Level
DQM[1:0]
Data Mask Enable Signals
Output
High
SDRAMC_A[12:0]
Address Bus
Output
D[15:0]
Data Bus
Input/Output
Application Example
Hardware Interface
Figure 16-2 on page 219 shows an example of SDRAM device connection using a 16-bit data
bus width. It is important to note that this example is given for a direct connection of the devices
to the SDRAMC, without External Bus Interface or I/O Controller multiplexing.
Figure 16-2. SDRAM Controller Connections to SDRAM Devices: 16-bit Data Bus Width
D0-D31
RAS
CAS
SDCK
SDCKE
SDWE
DQM[0-1]
SDRAM
Controller
D0-D7
DQM0
2Mx8
SDRAM
D0-D7
CS
CLK
CKE A0-A9 A11
WE
A10
RAS
BA0
CAS
BA1
DQM
D8-D15
SDRAMC_A10
BA0
BA1
DQM1
2Mx8
SDRAM
D0-D7
CS
CLK
CKE A0-A9 A11
WE
A10
RAS
BA0
CAS
BA1
DQM
SDRAMC_A10
BA0
BA1
SDRAMC_A[0-12]
BA0
BA1
NCS[1]
16.5.2
Software Interface
The SDRAM address space is organized into banks, rows, and columns. The SDRAMC allows
mapping different memory types according to the values set in the SDRAMC Configuration Register (CR).
The SDRAMC’s function is to make the SDRAM device access protocol transparent to the user.
Table 16-2 on page 220 to Table 16-4 on page 220 illustrate the SDRAM device memory mapping seen by the user in correlation with the device structure. Various configurations are
illustrated.
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16.5.2.1
16-bit memory data bus width
Table 16-2.
SDRAM Configuration Mapping: 2K Rows, 256/512/1024/2048 Columns
CPU Address Line
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
1
9
1
8
1
7
1
6
1
5
BA[1:0]
1
3
1
2
1
1
1
0
9
8
7
6
Row[10:0]
BA[1:0]
BA[1:0]
5
4
3
2
1
Column[7:0]
Row[10:0]
M0
Column[9:0]
Row[10:0]
0
M0
Column[8:0]
Row[10:0]
BA[1:0]
Table 16-3.
1
4
M0
Column[10:0]
M0
SDRAM Configuration Mapping: 4K Rows, 256/512/1024/2048 Columns
CPU Address Line
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
1
9
1
8
1
7
1
6
1
5
BA[1:0]
1
3
1
2
1
1
1
0
9
8
7
6
Row[11:0]
BA[1:0]
BA[1:0]
5
4
3
2
1
Column[7:0]
Row[11:0]
M0
Column[9:0]
Row[11:0]
0
M0
Column[8:0]
Row[11:0]
BA[1:0]
Table 16-4.
1
4
M0
Column[10:0]
M0
SDRAM Configuration Mapping: 8K Rows, 256/512/1024/2048 Columns
CPU Address Line
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
1
9
1
8
1
7
1
6
BA[1:0]
1
5
Row[12:0]
BA[1:0]
Row[12:0]
BA[1:0]
Row[12:0]
BA[1:0]
Row[12:0]
Notes:
1. M0 is the byte address inside a 16-bit halfword.
16.6
Product Dependencies
1
4
1
3
1
2
1
1
1
0
9
8
7
6
5
4
Column[7:0]
Column[8:0]
Column[9:0]
Column[10:0]
3
2
1
0
M0
M0
M0
M0
In order to use this module, other parts of the system must be configured correctly, as described
below.
16.6.1
I/O Lines
The SDRAMC module signals pass through the External Bus Interface (EBI) module where they
are multiplexed. The user must first configure the I/O controller to assign the EBI pins corresponding to SDRAMC signals to their peripheral function. If I/O lines of the EBI corresponding to
SDRAMC signals are not used by the application, they can be used for other purposes by the
I/O Controller.
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16.6.2
Power Management
The SDRAMC must be properly stopped before entering in reset mode, i.e., the user must issue
a Deep power mode command in the Mode (MD) register and wait for the command to be
completed.
16.6.3
Clocks
The clock for the SDRAMC bus interface (CLK_SDRAMC) is generated by the Power Manager.
This clock is enabled at reset, and can be disabled in the Power Manager. It is recommended to
disable the SDRAMC before disabling the clock, to avoid freezing the SDRAMC in an undefined
state.
16.6.4
Interrupts
The SDRAMC interrupt request line is connected to the interrupt controller. Using the SDRAMC
interrupt requires the interrupt controller to be programmed first.
16.7
16.7.1
Functional Description
SDRAM Device Initialization
The initialization sequence is generated by software. The SDRAM devices are initialized by the
following sequence:
1. SDRAM features must be defined in the CR register by writing the following fields with
the desired value: asynchronous timings (TXSR, TRAS, TRCD, TRP, TRC, and TWR),
Number of Columns (NC), Number of Rows (NR), Number of Banks (NB), CAS Latency
(CAS), and the Data Bus Width (DBW).
2. For mobile SDRAM devices, Temperature Compensated Self Refresh (TCSR), Drive
Strength (DS) and Partial Array Self Refresh (PASR) fields must be defined in the Low
Power Register (LPR).
3. The Memory Device Type field must be defined in the Memory Device Register
(MDR.MD).
4. A No Operation (NOP) command must be issued to the SDRAM devices to start the
SDRAM clock. The user must write the value one to the Command Mode field in the
SDRAMC Mode Register (MR.MODE) and perform a write access to any SDRAM
address.
5. A minimum pause of 200µs is provided to precede any signal toggle.
6. An All Banks Precharge command must be issued to the SDRAM devices. The user
must write the value two to the MR.MODE field and perform a write access to any
SDRAM address.
7. Eight Auto Refresh commands are provided. The user must write the value four to the
MR.MODE field and performs a write access to any SDRAM location eight times.
8. A Load Mode Register command must be issued to program the parameters of the
SDRAM devices in its Mode Register, in particular CAS latency, burst type, and burst
length. The user must write the value three to the MR.MODE field and perform a write
access to the SDRAM. The write address must be chosen so that BA[1:0] are set to
zero. See Section 16.8.1 for details about Load Mode Register command.
9. For mobile SDRAM initialization, an Extended Load Mode Register command must be
issued to program the SDRAM devices parameters (TCSR, PASR, DS). The user must
write the value five to the MR.MODE field and perform a write access to the SDRAM.
The write address must be chosen so that BA[1] or BA[0] are equal to one. See Section
16.8.1 for details about Extended Load Mode Register command.
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10. The user must go into Normal Mode, writing the value 0 to the MR.MODE field and performing a write access at any location in the SDRAM.
11. Write the refresh rate into the Refresh Timer Count field in the Refresh Timer Register
(TR.COUNT). The refresh rate is the delay between two successive refresh cycles. The
SDRAM device requires a refresh every 15.625µs or 7.81µs. With a 100MHz frequency, the TR register must be written with the value 1562 (15.625 µs x 100 MHz) or
781 (7.81 µs x 100 MHz).
After initialization, the SDRAM devices are fully functional.
Figure 16-3. SDRAM Device Initialization Sequence
SDCKE
tRP
tRC
tMRD
SDCK
SDRAMC_A[9:0]
A10
SDRAMC_A[12:11]
NCS[1]
RAS
CAS
SDWE
DQM
Inputs Stable for
200 usec
16.7.2
Precharge All Banks
1st Auto Refresh
8th Auto Refresh
LMR Command
Valid Command
SDRAM Controller Write Cycle
The SDRAMC allows burst access or single access. In both cases, the SDRAMC keeps track of
the active row in each bank, thus maximizing performance. To initiate a burst access, the
SDRAMC uses the transfer type signal provided by the master requesting the access. If the next
access is a sequential write access, writing to the SDRAM device is carried out. If the next
access is a write-sequential access, but the current access is to a boundary page, or if the next
access is in another row, then the SDRAMC generates a precharge command, activates the
new row and initiates a write command. To comply with SDRAM timing parameters, additional
clock cycles are inserted between precharge and active (tRP) commands and between active
and write (tRCD ) commands. For definition of these timing parameters, refer to the Section
16.8.3. This is described in Figure 16-4 on page 223.
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Figure 16-4. Write Burst, 16-bit SDRAM Access
tRCD = 3
NCS[1]
SDCK
SDRAMC_A[12:0]
Row n
Col a
Col b
Col c
Col d
Col e
Col f
Col g
Col h
Col i
Col j
Col k
Col l
Dnb
Dnc
Dnd
Dne
Dnf
Dng
Dnh
Dni
Dnj
Dnk
Dnl
RAS
CAS
SDWE
D[15:0]
16.7.3
Dna
SDRAM Controller Read Cycle
The SDRAMC allows burst access, incremental burst of unspecified length or single access. In
all cases, the SDRAMC keeps track of the active row in each bank, thus maximizing performance of the SDRAM. If row and bank addresses do not match the previous row/bank address,
then the SDRAMC automatically generates a precharge command, activates the new row and
starts the read command. To comply with the SDRAM timing parameters, additional clock cycles
on SDCK are inserted between precharge and active (tRP) commands and between active and
read (tRCD) commands. These two parameters are set in the CR register of the SDRAMC. After a
read command, additional wait states are generated to comply with the CAS latency (one, two,
or three clock delays specified in the CR register).
For a single access or an incremented burst of unspecified length, the SDRAMC anticipates the
next access. While the last value of the column is returned by the SDRAMC on the bus, the
SDRAMC anticipates the read to the next column and thus anticipates the CAS latency. This
reduces the effect of the CAS latency on the internal bus.
For burst access of specified length (4, 8, 16 words), access is not anticipated. This case leads
to the best performance. If the burst is broken (border, busy mode, etc.), the next access is handled as an incrementing burst of unspecified length.
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Figure 16-5. Read Burst, 16-bit SDRAM Access
tRCD = 3
CAS = 2
NCS[1]
SDCK
SDRAMC_A[12:0]
Row n
Col a
Col b
Col c
Col d
Col e
Col f
RAS
CAS
SDWE
D[15:0]
(Input)
16.7.4
Dna
Dnb
Dnc
Dnd
Dne
Dnf
Border Management
When the memory row boundary has been reached, an automatic page break is inserted. In this
case, the SDRAMC generates a precharge command, activates the new row and initiates a read
or write command. To comply with SDRAM timing parameters, an additional clock cycle is
inserted between the precharge and active (tRP) commands and between the active and read
(tRCD) commands. This is described in Figure 16-6 on page 225.
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Figure 16-6. Read Burst with Boundary Row Access
TRP = 3
CAS = 2
TRCD = 3
NCS[1]
SDCK
Row n
SDRAMC_A[12:0]
Col a
Col b
Col c
Col d
Row m
Col a
Col b
Col c
Col d
Col e
RAS
CAS
SDWE
D[15:0]
16.7.5
Dna
Dnb
Dnc
Dnd
Dma
Dmb
Dmc
Dmd
Dme
SDRAM Controller Refresh Cycles
An auto refresh command is used to refresh the SDRAM device. Refresh addresses are generated internally by the SDRAM device and incremented after each auto refresh automatically.
The SDRAMC generates these auto refresh commands periodically. An internal timer is loaded
with the value in the Refresh Timer Register (TR) that indicates the number of clock cycles
between successive refresh cycles.
A refresh error interrupt is generated when the previous auto refresh command did not perform.
In this case a Refresh Error Status bit is set in the Interrupt Status Register (ISR.RES). It is
cleared by reading the ISR register.
When the SDRAMC initiates a refresh of the SDRAM device, internal memory accesses are not
delayed. However, if the CPU tries to access the SDRAM, the slave indicates that the device is
busy and the master is held by a wait signal. See Figure 16-7 on page 226.
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Figure 16-7. Refresh Cycle Followed by a Read Access
tRP = 3
tRC = 8
tRCD = 3
CAS = 2
NCS[1]
SDCK
Row n
SDRAMC_A[12:0]
Col c Col d
Row m
Col a
RAS
CAS
SDWE
D[15:0]
(input)
16.7.6
Dnb
Dnc
Dnd
Dma
Power Management
Three low power modes are available:
• Self refresh mode: the SDRAM executes its own auto refresh cycles without control of the
SDRAMC. Current drained by the SDRAM is very low.
• Power-down mode: auto refresh cycles are controlled by the SDRAMC. Between auto refresh
cycles, the SDRAM is in power-down. Current drained in power-down mode is higher than in
self refresh mode.
• Deep power-down mode (only available with mobile SDRAM): the SDRAM contents are lost,
but the SDRAM does not drain any current.
The SDRAMC activates one low power mode as soon as the SDRAM device is not selected. It is
possible to delay the entry in self refresh and power-down mode after the last access by configuring the Timeout field in the Low Power Register (LPR.TIMEOUT).
16.7.6.1
Self refresh mode
This mode is selected by writing the value one to the Low Power Configuration Bits field in the
SDRAMC Low Power Register (LPR.LPCB). In self refresh mode, the SDRAM device retains
data without external clocking and provides its own internal clocking, thus performing its own
auto refresh cycles. All the inputs to the SDRAM device become “don’t care” except SDCKE,
which remains low. As soon as the SDRAM device is selected, the SDRAMC provides a
sequence of commands and exits self refresh mode.
Some low power SDRAMs (e.g., mobile SDRAM) can refresh only one quarter or a half quarter
or all banks of the SDRAM array. This feature reduces the self refresh current. To configure this
feature, Temperature Compensated Self Refresh (TCSR), Partial Array Self Refresh (PASR)
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and Drive Strength (DS) parameters must be set by writing the corresponding fields in the LPR
register, and transmitted to the low power SDRAM device during initialization.
After initialization, as soon as the LPR.PASR, LPR.DS, or LPR.TCSR fields are modified and
self refresh mode is activated, the SDRAMC issues an Extended Load Mode Register command
to the SDRAM and the Extended Mode Register of the SDRAM device is accessed automatically. The PASR/DS/TCSR parameters values are therefore updated before entry into self
refresh mode.
The SDRAM device must remain in self refresh mode for a minimum period of tRAS and may
remain in self refresh mode for an indefinite period. This is described in Figure 16-8 on page
227.
Figure 16-8. Self Refresh Mode Behavior
Self Refresh Mode
SDRAMC_A[12:0]
TXSR = 3
Row
SDCK
SDCKE
NCS[1]
RAS
CAS
SDWE
Access Request
To the SDRAM Controller
16.7.6.2
Low power mode
This mode is selected by writing the value two to the LPR.LPCB field. Power consumption is
greater than in self refresh mode. All the input and output buffers of the SDRAM device are
deactivated except SDCKE, which remains low. In contrast to self refresh mode, the SDRAM
device cannot remain in low power mode longer than the refresh period (64 ms for a whole
device refresh operation). As no auto refresh operations are performed by the SDRAM itself, the
SDRAMC carries out the refresh operation. The exit procedure is faster than in self refresh
mode.
This is described in Figure 16-9 on page 228.
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Figure 16-9. Low Power Mode Behavior
TRCD = 3
CAS = 2
Low Power Mode
NCS[1]
SDCK
SDRAMC_A[12:0]
Row n
Col a
Col b
Col c Col d
Col e
Col f
RAS
CAS
SDCKE
D[15:0]
(input)
16.7.6.3
Dna
Dnb
Dnc
Dnd
Dne
Dnf
Deep power-down mode
This mode is selected by writing the value three to the LPR.LPCB field. When this mode is activated, all internal voltage generators inside the SDRAM are stopped and all data is lost.
When this mode is enabled, the user must not access to the SDRAM until a new initialization
sequence is done (See Section 16.7.1).
This is described in Figure 16-10 on page 229.
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Figure 16-10. Deep Power-down Mode Behavior
tRP = 3
NCS[1]
SDCK
Row n
SDRAMC_A[12:0]
Col c
Col d
RAS
CAS
SDWE
SCKE
D[15:0]
(Input)
Dnb
Dnc
Dnd
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16.8
User Interface
Table 16-5.
SDRAMC Register Memory Map
Offset
Register
Register Name
Access
Reset
0x00
Mode Register
MR
Read/Write
0x00000000
0x04
Refresh Timer Register
TR
Read/Write
0x00000000
0x08
Configuration Register
CR
Read/Write
0x852372C0
0x0C
High Speed Register
HSR
Read/Write
0x00000000
0x10
Low Power Register
LPR
Read/Write
0x00000000
0x14
Interrupt Enable Register
IER
Write-only
0x00000000
0x18
Interrupt Disable Register
IDR
Write-only
0x00000000
0x1C
Interrupt Mask Register
IMR
Read-only
0x00000000
0x20
Interrupt Status Register
ISR
Read-only
0x00000000
0x24
Memory Device Register
MDR
Read/Write
0x00000000
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16.8.1
Mode Register
Register Name:
MR
Access Type:
Read/Write
Offset:
0x00
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
MODE
• MODE: Command Mode
This field defines the command issued by the SDRAMC when the SDRAM device is accessed.
MODE
Description
0
Normal mode. Any access to the SDRAM is decoded normally.
1
The SDRAMC issues a “NOP” command when the SDRAM device is accessed regardless of the cycle.
2
The SDRAMC issues an “All Banks Precharge” command when the SDRAM device is accessed regardless of
the cycle.
3
The SDRAMC issues a “Load Mode Register” command when the SDRAM device is accessed regardless of the
cycle. This command will load the CR.CAS field into the SDRAM device Mode Register. All the other parameters
of the SDRAM device Mode Register will be set to zero (burst length, burst type, operating mode, write burst
mode...).
4
The SDRAMC issues an “Auto Refresh” command when the SDRAM device is accessed regardless of the cycle.
Previously, an “All Banks Precharge” command must be issued.
5
The SDRAMC issues an “Extended Load Mode Register” command when the SDRAM device is accessed
regardless of the cycle. This command will load the LPR.PASR, LPR.DS, and LPR.TCR fields into the SDRAM
device Extended Mode Register. All the other bits of the SDRAM device Extended Mode Register will be set to
zero.
6
Deep power-down mode. Enters deep power-down mode.
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16.8.2
Refresh Timer Register
Register Name:
TR
Access Type:
Read/Write
Offset:
0x04
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
7
6
5
4
1
0
COUNT[11:8]
3
2
COUNT[7:0]
• COUNT[11:0]: Refresh Timer Count
This 12-bit field is loaded into a timer that generates the refresh pulse. Each time the refresh pulse is generated, a refresh burst
is initiated.
The value to be loaded depends on the SDRAMC clock frequency (CLK_SDRAMC), the refresh rate of the SDRAM device and
the refresh burst length where 15.6µs per row is a typical value for a burst of length one.
To refresh the SDRAM device, this 12-bit field must be written. If this condition is not satisfied, no refresh command is issued
and no refresh of the SDRAM device is carried out.
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16.8.3
Configuration Register
Register Name:
CR
Access Type:
Read/Write
Offset:
0x08
Reset Value:
0x852372C0
31
30
29
28
27
26
TXSR
23
22
21
14
20
19
18
13
DBW
6
16
12
11
10
9
8
1
0
TWR
5
CAS
17
TRP
TRC
7
24
TRAS
TRCD
15
25
4
NB
3
2
NR
NC
• TXSR: Exit Self Refresh to Active Delay
Reset value is eight cycles.
This field defines the delay between SCKE set high and an Activate command in number of cycles. Number of cycles is between
0 and 15.
• TRAS: Active to Precharge Delay
Reset value is five cycles.
This field defines the delay between an Activate command and a Precharge command in number of cycles. Number of cycles is
between 0 and 15.
• TRCD: Row to Column Delay
Reset value is two cycles.
This field defines the delay between an Activate command and a Read/Write command in number of cycles. Number of cycles
is between 0 and 15.
• TRP: Row Precharge Delay
Reset value is three cycles.
This field defines the delay between a Precharge command and another command in number of cycles. Number of cycles is
between 0 and 15.
• TRC: Row Cycle Delay
Reset value is seven cycles.
This field defines the delay between a Refresh and an Activate Command in number of cycles. Number of cycles is between 0
and 15.
• TWR: Write Recovery Delay
Reset value is two cycles.
This field defines the Write Recovery Time in number of cycles. Number of cycles is between 0 and 15.
• DBW: Data Bus Width
Reset value is 16 bits.
0: Reserved.
1: Data bus width is 16 bits.
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• CAS: CAS Latency
Reset value is two cycles.
In the SDRAMC, only a CAS latency of one, two and three cycles is managed.
CAS
CAS Latency (Cycles)
0
Reserved
1
1
2
2
3
3
• NB: Number of Banks
Reset value is two banks.
NB
Number of Banks
0
2
1
4
• NR: Number of Row Bits
Reset value is 11 row bits.
NR
Row Bits
0
11
1
12
2
13
3
Reserved
• NC: Number of Column Bits
Reset value is 8 column bits.
NC
Column Bits
0
8
1
9
2
10
3
11
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16.8.4
High Speed Register
Register Name:
HSR
Access Type:
Read/Write
Offset:
0x0C
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
DA
• DA: Decode Cycle Enable
A decode cycle can be added on the addresses as soon as a non-sequential access is performed on the HSB bus.
The addition of the decode cycle allows the SDRAMC to gain time to access the SDRAM memory.
1: Decode cycle is enabled.
0: Decode cycle is disabled.
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16.8.5
Low Power Register
Register Name:
LPR
Access Type:
Read/Write
Offset:
0x10
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
7
6
-
TIMEOUT
5
DS
4
PASR
TCSR
3
2
-
-
1
0
LPCB
• TIMEOUT: Time to Define when Low Power Mode Is Enabled
TIMEOUT
Time to Define when Low Power Mode Is Enabled
0
The SDRAMC activates the SDRAM low power mode immediately after the end of the last transfer.
1
The SDRAMC activates the SDRAM low power mode 64 clock cycles after the end of the last transfer.
2
The SDRAMC activates the SDRAM low power mode 128 clock cycles after the end of the last transfer.
3
Reserved.
• DS: Drive Strength (only for low power SDRAM)
This field is transmitted to the SDRAM during initialization to select the SDRAM strength of data output. This parameter must be
set according to the SDRAM device specification.
After initialization, as soon as this field is modified and self refresh mode is activated, the Extended Mode Register of the
SDRAM device is accessed automatically and its DS parameter value is updated before entry in self refresh mode.
• TCSR: Temperature Compensated Self Refresh (only for low power SDRAM)
This field is transmitted to the SDRAM during initialization to set the refresh interval during self refresh mode depending on the
temperature of the low power SDRAM. This parameter must be set according to the SDRAM device specification.
After initialization, as soon as this field is modified and self refresh mode is activated, the Extended Mode Register of the
SDRAM device is accessed automatically and its TCSR parameter value is updated before entry in self refresh mode.
• PASR: Partial Array Self Refresh (only for low power SDRAM)
This field is transmitted to the SDRAM during initialization to specify whether only one quarter, one half or all banks of the
SDRAM array are enabled. Disabled banks are not refreshed in self refresh mode. This parameter must be set according to the
SDRAM device specification.
After initialization, as soon as this field is modified and self refresh mode is activated, the Extended Mode Register of the
SDRAM device is accessed automatically and its PASR parameter value is updated before entry in self refresh mode.
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• LPCB: Low Power Configuration Bits
LPCB
Low Power Configuration
0
Low power feature is inhibited: no power-down, self refresh or deep power-down command is issued to
the SDRAM device.
1
The SDRAMC issues a self refresh command to the SDRAM device, the SDCLK clock is deactivated and
the SDCKE signal is set low. The SDRAM device leaves the self refresh mode when accessed and
enters it after the access.
2
The SDRAMC issues a power-down command to the SDRAM device after each access, the SDCKE
signal is set to low. The SDRAM device leaves the power-down mode when accessed and enters it after
the access.
3
The SDRAMC issues a deep power-down command to the SDRAM device. This mode is unique to lowpower SDRAM.
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16.8.6
Interrupt Enable Register
Register Name:
IER
Access Type:
Write-only
Offset:
0x14
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
RES
Writing a zero to a bit in this register has no effect.
Writing a one to a bit in this register will set the corresponding bit in IMR.
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16.8.7
Interrupt Disable Register
Register Name:
IDR
Access Type:
Write-only
Offset:
0x18
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
RES
Writing a zero to a bit in this register has no effect.
Writing a one to a bit in this register will clear the corresponding bit in IMR.
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16.8.8
Interrupt Mask Register
Register Name:
IMR
Access Type:
Read-only
Offset:
0x1C
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
RES
0: The corresponding interrupt is disabled.
1: The corresponding interrupt is enabled.
A bit in this register is cleared when the corresponding bit in IDR is written to one.
A bit in this register is set when the corresponding bit in IER is written to one.
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16.8.9
Interrupt Status Register
Register Name:
ISR
Access Type:
Read-only
Offset:
0x20
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
RES
• RES: Refresh Error Status
This bit is set when a refresh error is detected.
This bit is cleared when the register is read.
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16.8.10 Memory Device Register
Register Name:
MDR
Access Type:
Read/Write
Offset:
0x24
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
MD
• MD: Memory Device Type
MD
Device Type
0
SDRAM
1
Low power SDRAM
Other
Reserved
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17. Error Corrected Code Controller (ECCHRS)
Rev. 1.0.0.0
17.1
Features
• Hardware Error Corrected Code Generation with two methods :
•
•
•
•
17.2
– Hamming code detection and correction by software (ECC-H)
– Reed-Solomon code detection by hardware, correction by hardware or software (ECC-RS)
Supports NAND Flash and SmartMedia™ devices with 8- or 16-bit data path for ECC-H, and with
8-bit data path for ECC-RS
Supports NAND Flash and SmartMedia™ with page sizes of 528, 1056, 2112, and 4224 bytes
(specified by software)
ECC_H supports :
– One bit correction per page of 512,1024,2048, or 4096 bytes
– One bit correction per sector of 512 bytes of data for a page size of 512, 1024, 2048, or 4096
bytes
– One bit correction per sector of 256 bytes of data for a page size of 512, 1024, 2048, or 4096
bytes
ECC_RS supports :
– 4 errors correction per sector of 512 bytes of data for a page size of 512, 1024, 2048, and
4096 bytes with 8-bit data path
Overview
NAND Flash and SmartMedia™ devices contain by default invalid blocks which have one or
more invalid bits. Over the NAND Flash and SmartMedia™ lifetime, additional invalid blocks may
occur which can be detected and corrected by an Error Corrected Code (ECC).
The ECC Controller is a mechanism that encodes data in a manner that makes possible the
identification and correction of certain errors in data. The ECC controller is capable of single-bit
error correction and two-bit random detection when using the Hamming code (ECC-H) and fourerror correction whatever the number of erroneous bit in the byte error when using the Reed-Solomon code (ECC-RS).
When NAND Flash/SmartMedia™ have more than two erroneous bits when using the Hamming
code (ECC-H) or more than four bits in error when using the Reed-Solomon code (ECC-RS), the
data cannot be corrected.
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17.3
Block Diagram
Figure 17-1. ECCHRS Block Diagram
NAND Flash
SmartMedia
Logic
Encoder RS4
Rom 1024x10
Partial Syndrome
Static
Memory
Controller
10
GF(2 )
Polynomial
process
Error Evaluator
Chien Search
ECC Controller
Ctrl/ECC 1bit Algorithm
HECC
User Interface
Peripheral Bus
17.4
Product Dependencies
In order to use this module, other parts of the system must be configured correctly, as described
below.
17.4.1
I/O Lines
The ECCHRS signals pass through the External Bus Interface module (EBI) where they are
multiplexed.
The programmer must first configure the I/O Controller to assign the EBI pins corresponding to
the Static Memory Controller (SMC) signals to their peripheral function. If I/O lines of the EBI corresponding to SMC signals are not used by the application, they can be used for other purposes by
the I/O Controller.
17.4.2
Power Management
If the CPU enters a sleep mode that disables clocks used by the ECCHRS, the ECCHRS will
stop functioning and resume operation after the system wakes up from sleep mode.
17.4.3
Clocks
The clock for the ECCHRS bus interface (CLK_ECCHRS) is generated by the Power Manager.
This clock is enabled at reset, and can be disabled in the Power Manager. It is recommended to
disable the ECCHRS before disabling the clock, to avoid freezing the ECCHRS in an undefined
state.
17.4.4
Interrupts
The ECCHRS interrupt request line is connected to the interrupt controller. Using the ECCHRS
interrupt requires the interrupt controller to be programmed first.
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17.5
Functional Description
A page in NAND Flash and SmartMedia™ memories contains an area for main data and an additional area used for redundancy (ECC). The page is organized in 8-bit or 16-bit words. The page
size corresponds to the number of words in the main area plus the number of words in the extra
area used for redundancy.
Over time, some memory locations may fail to program or erase properly. In order to ensure that
data is stored properly over the life of the NAND Flash device, NAND Flash providers recommend to utilize either one ECC per 256 bytes of data, one ECC per 512 bytes of data, or one
ECC for all of the page. For the next generation of deep micron SLC NAND Flash and with the
new MLC NAND Flash, it is also recommended to ensure at least a four-error ECC per 512
bytes whatever is the page size.
The only configurations required for ECC are the NAND Flash or the SmartMedia™ page size
(528/1056/2112/4224) and the type of correction wanted (one ECC-H for all the page, one ECCH per 256 bytes of data, one ECC-H per 512 bytes of data, or four-error ECC-RS per 512 bytes
of data). The page size is configured by writing in the Page Size field in the Mode Register
(MD.PAGESIZE). Type of correction is configured by writing the Type of Correction field in the
Mode Register (MD.TYPECORREC).
The ECC is automatically computed as soon as a read (0x00) or a write (0x80) command to the
NAND Flash or the SmartMedia ™ is detected. Read and write access must start at a page
boundary.
The ECC results are available as soon as the counter reaches the end of the main area. The values in the Parity Registers (PR0 to PR15) for ECC-H and in the Codeword Parity registers
(CWPS00 to CWPS79) for ECC-RS are then valid and locked until a new start condition occurs
(read/write command followed by address cycles).
17.5.1
Write Access
Once the Flash memory page is written, the computed ECC codes are available in PR0 to PR15
registers for ECC-H and in CWPS00 to CWPS79 registers for ECC-RS. The ECC code values
must be written by the software application in the extra area used for redundancy. The number
of write access in the extra area depends on the value of the MD.TYPECORREC field.
For example, for one ECC per 256 bytes of data for a page of 512 bytes, only the values of PR0
and PR1 must be written by the software application in the extra area. For ECC-RS, a NAND
Flash with page of 512 bytes, the software application will have to write the ten registers
CWPS00 to CWPS09 in the extra area, and would have to write 40 registers (CWPS00 to
CWPS39) for a NAND Flash with page of 2048 bytes.
Other registers are meaningless.
17.5.2
Read Access
After reading the whole data in the main area, the application must perform read accesses to the
extra area where ECC code has been previously stored. Error detection is automatically performed by the ECC-H controller or the ECC-RS controller. In ECC-RS, writing a one to the Halt
of Computation bit in the ECC Mode Register (MD.FREEZE) allows to stop error detection when
software is jumping to the correct parity area.
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Figure 17-2. FREEZE signal waveform
Spare Zone
Nand Flash page 2048B
512B
512B
512B
512B
FREEZE
The application can check the ECC Status Registers (SR1/SR2) for any detected errors. It is up
to the application to correct any detected error for ECC-H. The application can correct any
detected error or let the hardware do the correction by writing a one to the Correction Enable bit
in the MD register (MD.CORRS4) for ECC-RS.
ECC computation can detect four different circumstances:
• No error: XOR between the ECC computation and the ECC code stored at the end of the
NAND Flash or SmartMedia™ page is equal to zero. All bits in the SR1 and SR2 registers will
be cleared.
• Recoverable error: Only the Recoverable Error bits in the ECC Status registers
(SR1.RECERRn and/or SR2.RECERRn) are set. The corrupted word offset in the read page
is defined by the Word Address field (WORDADDR) in the PR0 to PR15 registers. The
corrupted bit position in the concerned word is defined in the Bit Address field (BITADDR) in
the PR0 to PR15 registers.
• ECC error: The ECC Error bits in the ECC Status Registers (SR1.ECCERRn /
SR2.ECCERRn) are set. An error has been detected in the ECC code stored in the Flash
memory. The position of the corrupted bit can be found by the application performing an XOR
between the Parity and the NParity contained in the ECC code stored in the Flash memory.
For ECC-RS it is the responsibility of the software to determine where the error is located on
ECC code stored in the spare zone flash area and not on user data area.
• Non correctable error: The Multiple Error bits (MULERRn) in the SR1 and SR2 registers are
set. Several unrecoverable errors have been detected in the Flash memory page.
ECC Status Registers, ECC Parity Registers are cleared when a read/write command is
detected or a software reset is performed.
For Single-bit Error Correction and Double-bit Error Detection (SEC-DED) Hsiao code is used.
24-bit ECC is generated in order to perform one bit correction per 256 or 512 bytes for pages of
512/2048/4096 8-bit words. 32-bit ECC is generated in order to perform one bit correction per
512/1024/2048/4096 8- or 16-bit words.They are generated according to the schemes shown in
Figure 17-3 on page 247 and Figure 17-4 on page 248.
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Figure 17-3. Parity Generation for 512/1024/2048/4096 8-bit Words
1st byte
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
P8
2nd byte
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
P8'
3rd byte
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
P8
byte
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
P8'
(page size-3)th byte
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
P8
(page size-2)th byte
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
P8'
(page size-1)th byte
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
P8
page size th byte
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
P8'
P1
P1'
P1
P1'
P1
P1'
P1
P1'
th
4
P2
P2'
P2
P4
Page size = 512
Page size = 1024
Page size = 2048
Page size = 4096
P16
P32
PX
P16'
P16
PX’
P32'
P16'
P2'
P4'
P1=bit7(+)bit5(+)bit3(+)bit1(+)P1
P2=bit7(+)bit6(+)bit3(+)bit2(+)P2
P4=bit7(+)bit6(+)bit5(+)bit4(+)P4
P1'=bit6(+)bit4(+)bit2(+)bit0(+)P1'
P2'=bit5(+)bit4(+)bit1(+)bit0(+)P2'
P4'=bit7(+)bit6(+)bit5(+)bit4(+)P4'
Px = 2048
Px = 4096
Px = 8192
Px = 16384
To calculate P8’ to PX’ and P8 to PX, apply the algorithm that follows.
Page size = 2n
for i =0 to n
begin
for (j = 0 to page_size_byte)
begin
if(j[i] ==1)
P[2i+3]=bit7(+)bit6(+)bit5(+)bit4(+)bit3(+)
bit2(+)bit1(+)bit0(+)P[2i+3]
else
P[2i+3]’=bit7(+)bit6(+)bit5(+)bit4(+)bit3(+)
bit2(+)bit1(+)bit0(+)P[2i+3]'
end
end
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Figure 17-4. Parity Generation for 512/1024/2048/4096 16-bit Words
1st byte
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10
Bit 9
Bit 8
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
P8
byte
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10
Bit 9
Bit 8
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
P8'
3rd byte
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10
Bit 9
Bit 8
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
P8
4th byte
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10
Bit 9
Bit 8
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
P8'
(page size-3)th byte
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
P8
(page size-2)th byte
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
P8'
(page size-1)th byte
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
P8
page size th byte
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
P8'
P1
P1'
P1
P1'
P1
P1'
P1
P1'
P1
P1'
P1
P1'
P1
P1'
P1
P1'
nd
2
P2
P2'
P2
P4
P2'
P4'
P2
P2'
P5
Page size = 512
Page size = 1024
Page size = 2048
Page size = 4096
P2
P4
P16
P32
PX
P16'
P16
PX’
P32'
P16'
P2'
P4'
P5'
P1=bit15(+)bit13(+)bit11(+)bit9(+)bit7(+)bit5(+)bit3(+)bit1(+)P1
P2=bit15(+)bit14(+)bit11(+)bit10(+)bit7(+)bit6(+)bit3(+)bit2(+)P2
P4=bit15(+)bit14(+)bit13(+)bit12(+)bit7(+)bit6(+)bit5(+)bit4(+)P4
P5=bit15(+)bit14(+)bit13(+)bit12(+)bit11(+)bit10(+)bit9(+)bit8(+)P5
Px = 2048
Px = 4096
Px = 8192
Px = 16384
To calculate P8’ to PX’ and P8 to PX, apply the algorithm that follows.
Page size = 2n
for i =0 to n
begin
for (j = 0 to page_size_word)
begin
if(j[i] ==1)
P[2i+3]= bit15(+)bit14(+)bit13(+)bit12(+)
bit11(+)bit10(+)bit9(+)bit8(+)
bit7(+)bit6(+)bit5(+)bit4(+)bit3(+)
bit2(+)bit1(+)bit0(+)P[2n+3]
else
P[2i+3]’=bit15(+)bit14(+)bit13(+)bit12(+)
bit11(+)bit10(+)bit9(+)bit8(+)
bit7(+)bit6(+)bit5(+)bit4(+)bit3(+)
bit2(+)bit1(+)bit0(+)P[2i+3]'
end
end
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For ECC-RS, in order to perform 4-error correction per 512 bytes of 8-bit words, the codeword
have to be generated by the RS4 Encoder module and stored into the NAND Flash extra area,
according to the scheme shown in Figure 17-5 on page 249
Figure 17-5. RS Codeword Generation
Feedback
α28
α 500
CW7
+
α 397
CW6
+
α 402
CW5
+
α 603
CW4
+
α 395
CW3
+
α 383
CW2
+
α 539
CW1
+
+
DataIn
CW0
In read mode, firstly, the detection for any error is done with the partial syndrome module. It is
the responsibility of the ECC-RS Controller to determine after receiving the old codeword stored
in the extra area if there is any error on data and /or on the old codeword. If all syndromes (Si)
are equal to zero, there is no error, otherwise a polynomial representation is written into
CWPS00 to CWPS79 registers. The Partial Syndrome module performs an algorithm according
to the scheme in Figure 17-6 on page 249
Figure 17-6. Partial Syndrome Block Diagram
S7
Mult α i
x
x
x
RegOct
S2
S1
S0
DataIn(x)
If the Correction Enable bit is set in the ECC Mode Register (MD.CORRS4) then the polynomial
representation of error are sent to the polynomial processor. The aim of this module is to perform the polynomial division in order to calculate two polynomials, Omega (Z) and Lambda (Z),
which are necessary for the two following modules (Chien Search and Error Evaluator). In order
to perform addition, multiplication, and division a Read Only Memory (ROM) has been added
containing the 1024 elements of the Galois field. Both Chien Search and Error Evaluator work in
parallel. The Error Evaluator has the responsibility to determine the Nth error value in the data
and in the old codeword according to the scheme in Figure 17-7 on page 250
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Figure 17-7. Error Evaluator Block Diagram
ω0
α -1
α -3
α -4
α-5
α -7
ω1
ω3
ω4
ω5
ω7
+
ω (α )
-j
Λ odd( α )
-j
Rom 1024x10
10
GF(2 ) inverted
Error value
@ position j
Array - Mult
ErrorLoc
The Chien Search takes charge of determining if an error has occurred at symbol N according to
the scheme in Figure 17-8 on page 250
Figure 17-8. Chien Search Block Diagram
λ 00
α-2
α-8
α-1
α-3
α-7
λ2
λ8
λ1
λ3
λ7
+
Degree of Lambda
+
+
Λ (α )
-j
Error Located
counter
Flag error
Not
Error located
Λ odd(α )
-j
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17.6
User Interface
Table 17-1.
Note:
ECCHRS Register Memory Map
Offset
Register
Name
Access
Reset
0x000
Control Register
CTRL
Write-only
0x00000000
0x004
Mode Register
MD
Read/write
0x00000000
0x008
Status Register 1
SR1
Read-only
0x00000000
0x00C
Parity Register 0
PR0
Read-only
0x00000000
0x010
Parity Register 1
PR1
Read-only
0x00000000
0x014
Status Register 2
SR2
Read-only
0x00000000
0x018
Parity Register 2
PR2
Read-only
0x00000000
0x01C
Parity Register 3
PR3
Read-only
0x00000000
0x020
Parity Register 4
PR4
Read-only
0x00000000
0x024
Parity Register 5
PR5
Read-only
0x00000000
0x028
Parity Register 6
PR6
Read-only
0x00000000
0x02C
Parity Register 7
PR7
Read-only
0x00000000
0x030
Parity Register 8
PR8
Read-only
0x00000000
0x034
Parity Register 9
PR9
Read-only
0x00000000
0x038
Parity Register 10
PR10
Read-only
0x00000000
0x03C
Parity Register 11
PR11
Read-only
0x00000000
0x040
Parity Register 12
PR12
Read-only
0x00000000
0x044
Parity Register 13
PR13
Read-only
0x00000000
0x048
Parity Register 14
PR14
Read-only
0x00000000
0x04C
Parity Register 15
PR15
Read-only
0x00000000
0x050 - 0x18C
Codeword and Syndrome 00 Codeword and Syndrome 79
CWPS00 CWPS79
Read-only
0x00000000
0x190 - 0x19C
MaskData 0 - Mask Data 3
MDATA0 - MDATA3
Read-only
0x00000000
0x1A0 - 0x1AC
Address Offset 0 - Address Offset 3
ADOFF0 - ADOFF3
Read-only
0x00000000
0x1B0
Interrupt Enable Register
IER
Write-only
0x00000000
0x1B4
Interrupt Disable Register
IDR
Write-only
0x00000000
0x1B8
Interrupt Mask Register
MR
Read-only
0x00000000
0x1BC
Interrupt Status Register
ISR
Read-only
0x00000000
0x1C0
Interrupt Status Clear Register
ISCR
Write-only
0x00000000
0x1FC
Version Register
VERSION
Read-only
-(1)
1. The reset value is device specific. Please refer to the Module Configuration section at the end of this chapter.
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17.6.1
Name:
Control Register
CR
Access Type:
Write-only
Offset:
0x000
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
RST
• RST: RESET Parity
Writing a one to this bit will reset the ECC Parity registers.
Writing a zero to this bit has no effect.
This bit always reads as zero.
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17.6.2
Name:
Mode Register
MD
Access Type:
Read/Write
Offset:
0x004
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
CORRS4
-
FREEZE
7
6
5
4
3
2
1
0
-
TYPECORREC
-
PAGESIZE
• CORRS4: Correction Enable
Writing a one to this bit will enable the correction to be done after the Partial Syndrome process and allow interrupt to be sent to
CPU.
Writing a zero to this bit will stop the correction after the Partial Syndrome process.
1: The correction will continue after the Partial Syndrome process.
0: The correction will stop after the Partial Syndrome process.
• FREEZE: Halt of Computation
Writing a one to this bit will stop the computation.
Writing a zero to this bit will allow the computation as soon as read/write command to the NAND Flash or the SmartMedia™ is
detected.
1: The computation will stop until a zero is written to this bit.
0: The computation is allowed.
• TYPECORREC: Type of Correction
ECC code
TYPECORREC
Description
0b000
One bit correction per page
0b001
One bit correction per sector of 256 bytes
0b010
One bit correction per sector of 512 bytes
ECC-RS
0b100
Four bits correction per sector of 512 bytes
-
Others
Reserved
ECC-H
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• PAGESIZE: Page Size
This table defines the page size of the NAND Flash device when using the ECC-H code (TYPECORREC = 0b0xx).
Page Size
Description
0
528 words
1
1056 words
2
2112 words
3
4224 words
Others
Reserved
A word has a value of 8 bits or 16 bits, depending on the NAND Flash or SmartMedia™ memory organization.
This table defines the page size of the NAND Flash device when using the ECC-RS code (TYPECORREC = 0b1xx)
Page Size
Description
Comment
0
528 bytes
1 page of 512 bytes
1
1056 bytes
2 pages of 512 bytes
2
1584 bytes
3 pages of 512 bytes
3
2112 bytes
4 pages of 512 bytes
4
2640 bytes
5 pages of 512 bytes
5
3168 bytes
6 pages of 512 bytes
6
3696 bytes
7 pages of 512 bytes
7
4224 bytes
8 pages of 512 bytes
i.e.: for NAND Flash device with page size of 4096 bytes and 128 bytes extra area ECC-RS can manage any sub page of
512 bytes up to 8.
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17.6.3
Name:
Status Register 1
SR1
Access Type:
Read-only
Offset:
0x008
Reset Value:
0x000000000
MD.TYPECORREC=0b0xx, using ECC-H code
31
30
29
28
27
26
25
24
-
MULERR7
ECCERR7
RECERR7
-
MULERR6
ECCERR6
RECERR6
23
22
21
20
19
18
17
16
-
MULERR5
ECCERR5
RECERR5
-
MULERR4
ECCERR4
RECERR4
15
14
13
12
11
10
9
8
-
MULERR3
ECCERR3
RECERR3
-
MULERR2
ECCERR2
RECERR2
7
6
5
4
3
2
1
0
-
MULERR1
ECCERR1
RECERR1
-
MULERR0
ECCERR0
RECERR0
• MULERRn: Multiple Error in the sector number n of 256/512 bytes in the page
1: Multiple errors are detected.
0: No multiple error is detected.
TYPECORREC
Sector Size
Comments
0
page size
1
256
MULERR0 to MULERR7 are used depending on the page size
2
512
MULERR0 to MULERR7 are used depending on the page size
Others
Reserved
Only MULERR0 is used
• ECCERRn: ECC Error in the packet number n of 256/512 bytes in the page
1: A single bit error has occurred.
0: No error have been detected.
TYPECORREC
Sector Size
Comments
0
page size
1
256
ECCERR0 to ECCERR7 are used depending on the page size
2
512
ECCERR0 to ECCERR7 are used depending on the page size
Others
Reserved
Only ECCERR0 is used
The user should read PR0 and PR1 to know where the error occurs
in the page.
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• RECERRn: Recoverable Error in the packet number n of 256/512 Bytes in the page
1: Errors detected. If MULERRn is zero, a single correctable error was detected. Otherwise multiple uncorrected errors were
detected.
0: No errors have been detected.
TYPECORREC
sector size
Comments
0
page size
1
256
RECERR0 to RECERR7 are used depending on the page size
2
512
RECERR0 to RECERR7 are used depending on the page size
Others
Reserved
Only RECERR0 is used
MD.TYPECORREC=0b1xx, using ECC-RS code
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
SYNVEC
• SYNVEC: Syndrome Vector
After reading a page made of n sector of 512 bytes, this field returns which sector contains error detected after the syndrome
analysis.
The SYNVEC[n] bit is set when there is at least one error in the corresponding sector.
The SYNVEC[n] bit is cleared when a read/write command is detected or a software reset is performed.
1: At least one error has occurred in the corresponding sector.
0: No error has been detected.
Bit Index (n)
Sector Boundaries
0
0-511
1
512-1023
2
1023-1535
3
1536-2047
4
2048-2559
256
32072C–AVR32–2010/03
AT32UC3A3/A4
Bit Index (n)
Sector Boundaries
5
2560-3071
6
3072-3583
7
3584-4095
257
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17.6.4
Name:
Parity Register 0
PR0
Access Type:
Read-only
Offset:
0x00C
Reset Value:
0x00000000
Using ECC-H code, one bit correction per page (MD.TYPECORREC=0b000)
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
2
1
0
WORDADDR[11:4]
7
6
5
4
3
WORDADDR[3:0]
BITADDR
Once the entire main area of a page is written with data, this register content must be stored at any free location of the spare
area.
• WORDADDR: Word Address
During a page read, this field contains the word address (8-bit or 16-bit word, depending on the memory plane organization)
where an error occurred, if a single error was detected. If multiple errors were detected, this field is meaningless.
• BITADDR: Bit Address
During a page read, this field contains the corrupted bit offset where an error occurred, if a single error was detected. If multiple
errors were detected, this field is meaningless.
Using ECC-H code, one bit correction per sector of 256 bytes (MD.TYPECORREC=0b001)
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
10
9
8
-
15
NPARITY0[10:4]
14
13
12
11
258
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NPARITY0[3:0]
7
6
0
5
WORDADD0[4:0]
4
3
WORDADD0[7:5]
2
1
0
BITADDR0
Once the entire main area of a page is written with data, this register content must be stored at any free location of the spare
area.
• NPARITY0: Parity N
Parity calculated by the ECC-H.
• WORDADDR0: Corrupted Word Address in the page between the first byte and the 255th byte
During a page read, this field contains the word address (8-bit word) where an error occurred, if a single error was detected. If
multiple errors were detected, this field is meaningless.
• BITADDR0: Corrupted Bit Address in the page between the first byte and the 255th byte
During a page read, this field contains the corrupted bit offset where an error occurred, if a single error was detected. If multiple
errors were detected, this field is meaningless.
259
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Using ECC-H code, one bit correction per sector of 512 bytes (MD.TYPECORREC=0b010)
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
10
9
8
NPARITY0[11:4]
15
14
13
12
11
NPARITY0[3:0]
7
6
WORDADD0[8:5]
5
WORDADD0[4:0]
4
3
2
1
0
BITADDR0
Once the entire main area of a page is written with data, this register content must be stored at any free location of the spare
area.
• NPARITY0: Parity N
Parity calculated by the ECC-H.
• WORDADDR0: Corrupted Word Address in the page between the first byte and the 511th byte
During a page read, this field contains the word address (8-bit word) where an error occurred, if a single error was detected. If
multiple errors were detected, this field is meaningless.
• BITADDR0: Corrupted Bit Address in the page between the first byte and the 511th byte
During a page read, this field contains the corrupted bit offset where an error occurred, if a single error was detected. If multiple
errors were detected, this field is meaningless.
260
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17.6.5
Name:
Parity Register 1
PR1
Access Type:
Read-only
Offset:
0x010
Reset Value:
0x00000000
Using ECC-H code, one bit correction per page (MD.TYPECORREC=0b000)
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
2
1
0
NPARITY[15:8]
7
6
5
4
3
NPARITY[7:0]
• NPARITY: Parity N
During a write, the field of this register must be written in the extra area used for redundancy (for a 512-byte page size:
address 514-515).
Using ECC-H code, one bit correction per sector of 256 bytes (MD.TYPECORREC=0b001)
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
10
9
8
-
15
NPARITY1[10:0]
14
13
12
NPARITY1[3:0]
7
6
11
0
5
WORDADD1[4:0]
4
3
WORDADD1[7:5]
2
1
0
BITADDR1
261
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Once the entire main area of a page is written with data, this register content must be stored at any free location of the spare
area.
• NPARITY1: Parity N
Parity alculated by the ECC-H.
• WORDADDR1: corrupted Word Address in the page between the 256th and the 511th byte
During a page read, this field contains the word address (8-bit word) where an error occurred, if a single error was detected. If
multiple errors were detected, this field is meaningless.
• BITADDR1: corrupted Bit Address in the page between the 256th and the 511th byte
During a page read, this field contains the corrupted bit offset where an error occurred, if a single error was detected. If multiple
errors were detected, this field is meaningless.
Using ECC-H code, one bit correction per sector of 512 bytes (MD.TYPECORREC=0b010)
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
10
9
8
NPARITY1[11:4]
15
14
13
12
11
NPARITY1[3:0]
7
6
WORDADD1[8:5]
5
WORDADD1[4:0]
4
3
2
1
0
BITADDR1
Once the entire main area of a page is written with data, this register content must be stored at any free location of the spare
area.
• NPARITY1: Parity N
Parity calculated by the ECC-H.
• WORDADDR1: Corrupted Word Address in the page between the 512th and the 1023th byte
During a page read, this field contains the word address (8-bit word) where an error occurred, if a single error was detected. If
multiple errors were detected, this field is meaningless.
• BITADDR1: Corrupted Bit Address in the page between the 512th and the 1023th byte
During a page read, this field contains the corrupted bit offset where an error occurred, if a single error was detected. If multiple
errors were detected, this field is meaningless.
262
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17.6.6
Name:
Status Register 2
SR2
Access Type:
Read-only
Offset:
0x014
Reset Value:
0x00000000
MD.TYPECORREC=0b0xx, using ECC-H code
31
30
29
28
27
26
25
24
-
MULERR15
ECCERR15
RECERR15
-
MULERR14
ECCERR14
RECERR14
23
22
21
20
19
18
17
16
-
MULERR13
ECCERR13
RECERR13
-
MULERR12
ECCERR12
RECERR12
15
14
13
12
11
10
9
8
-
MULERR11
ECCERR11
RECERR11
-
MULERR10
ECCERR10
RECERR10
7
6
5
4
3
2
1
0
-
MULERR9
ECCERR9
RECERR9
-
MULERR8
ECCERR8
RECERR8
• MULERRn: Multiple Error in the sector number n of 256/512 bytes in the page
1: Multiple errors are detected.
0: No multiple error is detected.
TYPECORREC
Sector Size
Comments
0
page size
1
256
MULERR0 to MULERR7 are used depending on the page size
2
512
MULERR0 to MULERR7 are used depending on the page size
Others
Reserved
Only MULERR0 is used
• ECCERRn: ECC Error in the packet number n of 256/512 bytes in the page
1: A single bit error has occurred.
0: No error is detected.
TYPECORREC
sector size
Comments
0
page size
1
256
ECCERR0 to ECCERR7 are used depending on the page size
2
512
ECCERR0 to ECCERR7 are used depending on the page size
Others
Reserved
Only ECCERR0 is used
The user should read PR0 and PR1 to know where the error occurs
in the page.
263
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MD.TYPECORREC=0b1xx, using ECC-RS code
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
MULERR
RECERR
Only one sub page of 512 bytes is corrected at a time. If several sub page are on error then it is necessary to do several time the
correction process.
• MULERR: Multiple error
This bit is set to one when a multiple error have been detected by the ECC-RS.
This bit is cleared when a read/write command is detected or a software reset is performed.
1: Multiple errors detected: more than four errors.Registers for one ECC for a page of 512/1024/2048/4096 bytes
0: No multiple error detected
• RECERR: Number of recoverable errors if MULERR is zero
RECERR
Comments
000
no error
001
one single error detected
010
two errors detected
011
three errors detected
100
four errors detected
264
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AT32UC3A3/A4
17.6.7
Name:
Parity Register 2 - 15
PR2 - PR15
Access Type:
Read-only
Offset:
0x018 - 0x04C
Reset Value:
0x00000000
Using ECC-H code, one bit correction per sector of 256 bytes (MD.TYPECORREC=0b001)
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
10
9
8
15
NPARITYn[10:4]
14
13
12
NPARITYn[3:0]
7
6
11
0
5
WORDADDn[4:0]
4
3
WORDADDn[7:5]
2
1
0
BITADDRn
Once the entire main area of a page is written with data, this register content must be stored at any free location of the spare
area.
• NPARITYn: Parity N
Parity calculated by the ECC-H.
• WORDADDRn: corrupted Word Address in the packet number n of 256 bytes in the page
During a page read, this field contains the word address (8-bit word) where an error occurred, if a single error was detected. If
multiple errors were detected, this field is meaningless.
• BITADDRn: corrupted Bit Address in the packet number n of 256 bytes in the page
During a page read, this field contains the corrupted bit offset where an error occurred, if a single error was detected. If multiple
errors were detected, this field is meaningless.
265
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AT32UC3A3/A4
Using ECC-H code, one bit correction per sector of 512 bytes (MD.TYPECORREC=0b010)
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
10
9
8
NPARITYn[11:4]
15
14
13
12
11
NPARITYn[3:0]
7
6
WORDADDn[8:5]
5
WORDADDn[4:0]
4
3
2
1
0
BITADDRn
Once the entire main area of a page is written with data, this register content must be stored to any free location of the spare
area.
Only PR2 to PR7 registers are available in this case.
• NPARITYn: Parity N
Parity calculated by the ECC-H.
• WORDADDRn: corrupted Word Address in the packet number n of 512 bytes in the page
During a page read, this field contains the word address (8-bit word) where an error occurred, if a single error was detected. If
multiple errors were detected, this field is meaningless.
• BITADDRn: corrupted Bit Address in the packet number n of 512 bytes in the page
During a page read, this field contains the corrupted bit offset where an error occurred, if a single error was detected. If multiple
errors were detected, this field is meaningless.
266
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AT32UC3A3/A4
17.6.8
Name:
Codeword 00 - Codeword79
CWPS00 - CWPS79
Access Type:
Read-only
Offset:
0x050 - 0x18C
Reset Value:
0x00000000
Page Write:
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
CODEWORD
• CODEWORD:
Once the 512 bytes of a page is written with data, this register content must be stored to any free location of the spare area.
For a page of 512 bytes the entire redundancy words are made of 8 words of 10 bits. All those redundancies words are
concatenated to a word of 80 bits and then cut to 10 words of 8 bits to facilitate their writing in the extra area.
At the end of a page write, this field contains the redundancy word to be stored to the extra area.
Page Read:
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
PARSYND
267
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AT32UC3A3/A4
• PARSYND:
At the end of a page read, this field contains the Partial Syndrome S.
PARSYND00-PARSYND09: this conclude all the codeword and partial syndrome word for the sub page 1
PARSYND10-PARSYND19: this conclude all the codeword and partial syndrome word for the sub page 2
PARSYND20-PARSYND29: this conclude all the codeword and partial syndrome word for the sub page 3
PARSYND30-PARSYND39: this conclude all the codeword and partial syndrome word for the sub page 4
PARSYND40-PARSYND49: this conclude all the codeword and partial syndrome word for the sub page 5
PARSYND50-PARSYND59: this conclude all the codeword and partial syndrome word for the sub page 6
PARSYND60-PARSYND69: this conclude all the codeword and partial syndrome word for the sub page 7
PARSYND70-PARSYND79: this conclude all the codeword and partial syndrome word for the sub page 8
268
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AT32UC3A3/A4
17.6.9
Name:
Mask Data 0 - Mask Data 3
MDATA0 -MDATA3
Access Type:
Read-only
Offset:
0x190 - 0x19C
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
7
6
5
4
3
2
MASKDATA[9:8]
1
0
MASKDATA[7:0]
• MASKDATA:
At the end of the correction process, this field contains the mask to be XORed with the data read to perform the final
correction.This XORed is under the responsibility of the software.
This field is meaningless if MD.CORRS4 is zero.
269
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AT32UC3A3/A4
17.6.10
Name:
Address Offset 0 - Address Offset 3
ADOFF0 - ADOFF3
Access Type:
Read-only
Offset:
0x1A0 - 0x1AC
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
7
6
5
4
3
2
OFFSET[9:8]
1
0
OFFSET[7:0]
• OFFSET:
At the end of correction process, this field contains the offset address of the data read to be corrected.
This field is meaningless if MD.CORRS4 is zero.
270
32072C–AVR32–2010/03
AT32UC3A3/A4
17.6.11
Name:
Interrupt Enable Register
IER
Access Type:
Write-only
Offset:
0x1B0
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
ENDCOR
• ENDCOR:
Writing a zero to this bit has no effect.
Writing a one to this bit will set the corresponding bit in IMR.
271
32072C–AVR32–2010/03
AT32UC3A3/A4
17.6.12
Name:
Interrupt Disable Register
IDR
Access Type:
Write-only
Offset:
0x1B4
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
ENDCOR
• ENDCOR:
Writing a zero to this bit has no effect.
Writing a one to this bit will clear the corresponding bit in IMR.
272
32072C–AVR32–2010/03
AT32UC3A3/A4
17.6.13
Name:
Interrupt Mask Register
IMR
Access Type:
Read-only
Offset:
0x1B8
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
ENDCOR
• ENDCOR:
0: The corresponding interrupt is disabled.
1: The corresponding interrupt is enabled.
This bit is cleared when the corresponding bit in IDR is written to one.
This bit is set when the corresponding bit in IER is written to one.
273
32072C–AVR32–2010/03
AT32UC3A3/A4
17.6.14
Name:
Interrupt Status Register
ISR
Access Type:
Read-only
Offset:
0x1BC
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
ENDCOR
• ENDCOR:
This bit is cleared when the corresponding bit in ISCR is written to one.
This bit is set when a correction process has ended.
274
32072C–AVR32–2010/03
AT32UC3A3/A4
17.6.15
Name:
Interrupt Status Clear Register
ISCR
Access Type:
Write-only
Offset:
0x1C0
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
ENDCOR
• ENDCOR:
Writing a zero to this bit has no effect
Writing a one to this bit will clear the corresponding bit in ISR and the corresponding interrupt request.
275
32072C–AVR32–2010/03
AT32UC3A3/A4
17.6.16
Name:
Version Register
VERSION
Access Type:
Read-only
Offset:
0x1FC
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
15
14
13
12
11
-
-
-
-
7
6
5
4
VARIANT
10
9
8
VERSION[11:8]
3
2
1
0
VERSION[7:0]
• VARIANT: Variant Number
Reserved. No functionality associated.
• VERSION: Version Number
Version number of the module. No functionality associated.
276
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AT32UC3A3/A4
17.7
Module Configuration
The specific configuration for the ECCHRS instance is listed in the following tables.The module
bus clocks listed here are connected to the system bus clocks according to the table in the
Power Manager section.
Table 17-2.
Module clock name
Module name
Clock name
ECCHRS
CLK_ECCHRS
Table 17-3.
Register Reset Values
Register
Reset Value
VERSION
0x00000100
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18. Peripheral DMA Controller (PDCA)
Rev: 1.1.0.1
18.1
Features
•
•
•
•
18.2
Multiple channels
Generates transfers to/from peripherals such as USART and SPI
Two address pointers/counters per channel allowing double buffering
Performance monitors to measure average and maximum transfer latency
Overview
The Peripheral DMA Controller (PDCA) transfers data between on-chip peripheral modules such
as USART, SPI and memories (those memories may be on- and off-chip memories). Using the
PDCA avoids CPU intervention for data transfers, improving the performance of the microcontroller. The PDCA can transfer data from memory to a peripheral or from a peripheral to memory.
The PDCA consists of multiple DMA channels. Each channel has:
• A Peripheral Select Register
• A 32-bit memory pointer
• A 16-bit transfer counter
• A 32-bit memory pointer reload value
• A 16-bit transfer counter reload value
The PDCA communicates with the peripheral modules over a set of handshake interfaces. The
peripheral signals the PDCA when it is ready to receive or transmit data. The PDCA acknowledges the request when the transmission has started.
When a transmit buffer is empty or a receive buffer is full, an optional interrupt request can be
generated.
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18.3
Block Diagram
Figure 18-1. PDCA Block Diagram
Peripheral
0
HSB to PB
Bridge
Peripheral Bus
HSB
High Speed
Bus Matrix
HSB
Interrupt
Controller
IRQ
Peripheral
2
...
Peripheral DMA
Controller
(PDCA)
Peripheral
1
Peripheral
(n-1)
Handshake Interfaces
18.4
Product Dependencies
In order to use this module, other parts of the system must be configured correctly, as described
below.
18.4.1
Power Management
If the CPU enters a sleep mode that disables the PDCA clocks, the PDCA will stop functioning
and resume operation after the system wakes up from sleep mode.
18.4.2
Clocks
The PDCA has two bus clocks connected: One High Speed Bus clock (CLK_PDCA_HSB) and
one Peripheral Bus clock (CLK_PDCA_PB). These clocks are generated by the Power Manager. Both clocks are enabled at reset, and can be disabled by writing to the Power Manager. It
is recommended to disable the PDCA before disabling the clocks, to avoid freezing the PDCA in
an undefined state.
18.4.3
Interrupts
The PDCA interrupt request lines are connected to the interrupt controller. Using the PDCA
interrupts requires the interrupt controller to be programmed first.
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18.5
18.5.1
Functional Description
Basic Operation
The PDCA consists of multiple independent PDCA channels, each capable of handling DMA
requests in parallel. Each PDCA channels contains a set of configuration registers which must
be configured to start a DMA transfer.
In this section the steps necessary to configure one PDCA channel is outlined.
The peripheral to transfer data to or from must be configured correctly in the Peripheral Select
Register (PSR). This is performed by writing the Peripheral Identity (PID) value for the corresponding peripheral to the PID field in the PSR register. The PID also encodes the transfer
direction, i.e. memory to peripheral or peripheral to memory. See Section 18.5.5.
The transfer size must be written to the Transfer Size field in the Mode Register (MR.SIZE). The
size must match the data size produced or consumed by the selected peripheral. See Section
18.5.6.
The memory address to transfer to or from, depending on the PSR, must be written to the Memory Address Register (MAR). For each transfer the memory address is increased by either a
one, two or four, depending on the size set in MR. See Section 18.5.2.
The number of data items to transfer is written to the TCR register. If the PDCA channel is
enabled, a transfer will start immediately after writing a non-zero value to TCR or the reload version of TCR, TCRR. After each transfer the TCR value is decreased by one. Both MAR and TCR
can be read while the PDCA channel is active to monitor the DMA progress. See Section 18.5.3.
The channel must be enabled for a transfer to start. A channel is enable by writing a one to the
EN bit in the Control Register (CR).
18.5.2
Memory Pointer
Each channel has a 32-bit Memory Address Register (MAR). This register holds the memory
address for the next transfer to be performed. The register is automatically updated after each
transfer. The address will be increased by either one, two or four depending on the size of the
DMA transfer (byte, halfword or word). The MAR can be read at any time during transfer.
18.5.3
Transfer Counter
Each channel has a 16-bit Transfer Counter Register (TCR). This register must be programmed
with the number of transfers to be performed. The TCR register should contain the number of
data items to be transferred independently of the transfer size. The TCR can be read at any time
during transfer to see the number of remaining transfers.
18.5.4
Reload Registers
Both the MAR and the TCR have a reload register, respectively Memory Address Reload Register (MARR) and Transfer Counter Reload Register (TCRR). These registers provide the
possibility for the PDCA to work on two memory buffers for each channel. When one buffer has
completed, MAR and TCR will be reloaded with the values in MARR and TCRR. The reload logic
is always enabled and will trigger if the TCR reaches zero while TCRR holds a non-zero value.
After reload, the MARR and TCRR registers are cleared.
If TCR is zero when writing to TCRR, the TCR and MAR are automatically updated with the
value written in TCRR and MARR.
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18.5.5
Peripheral Selection
The Peripheral Select Register (PSR) decides which peripheral should be connected to the
PDCA channel. A peripheral is selected by writing the corresponding Peripheral Identity (PID) to
the PID field in the PST register. Writing the PID will both select the direction of the transfer
(memory to peripheral or peripheral to memory), which handshake interface to use, and the
address of the peripheral holding register. Refer to the Peripheral Identity (PID) table in the Module Configuration section for the peripheral PID values.
18.5.6
Transfer Size
The transfer size can be set individually for each channel to be either byte, halfword or word (8bit, 16-bit or 32-bit respectively). Transfer size is set by writing the desired value to the Transfer
Size field in the Mode Register (MR.SIZE).
When the PDCA moves data between peripherals and memory, data is automatically sized and
aligned. When memory is accessed, the size specified in MR.SIZE and system alignment is
used. When a peripheral register is accessed the data to be transferred is converted to a word
where bit n in the data corresponds to bit n in the peripheral register. If the transfer size is byte or
halfword, bits greater than 8 and16 respectively are set to zero.
Refer to the Module Configuration section for information regarding what peripheral registers are
used for the differen peripherals and then to the peripheral specific chapter for information about
the size option available for the different registers.
18.5.7
Enabling and Disabling
Each DMA channel is enabled by writing a one to the Transfer Enable bit in the Control Register
(CR.TEN) and disabled by writing a one to the Transfer Disable bit (CR.TDIS). The current status can be read from the Status Register (SR).
While the PDCA channel is enabled all DMA request will be handled as long the TCR and TCRR
is not zero.
18.5.8
Interrupts
Interrupts can be enabled by writing a one to the corresponding bit in the Interrupt Enable Register (IER) and disabled by writing a one to the corresponding bit in the Interrupt Disable Register
(IDR). The Interrupt Mask Register (IMR) can be read to see whether an interrupt is enabled or
not. The current status of an interrupt source can be read through the Interrupt Status Register
(ISR).
The PDCA has three interrupt sources:
• Reload Counter Zero - The TCRR register is zero.
• Transfer Finished - Both the TCR and TCRR registers are zero.
• Transfer Error - An error has occurred in accessing memory.
18.5.9
Priority
If more than one PDCA channel is requesting transfer at a given time, the PDCA channels are
prioritized by their channel number. Channels with lower numbers have priority over channels
with higher numbers, giving channel zero the highest priority.
18.5.10
Error Handling
If the Memory Address Register (MAR) is set to point to an invalid location in memory, an error
will occur when the PDCA tries to perform a transfer. When an error occurs, the Transfer Error
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bit in the Interrupt Status Register (ISR.TERR) will be set and the DMA channel that caused the
error will be stopped. In order to restart the channel, the user must program the Memory
Address Register to a valid address and then write a one to the Error Clear bit in the Control
Register (CR.ECLR). If the Transfer Error interrupt is enabled, an interrupt request will be generated when an transfer error occurs.
18.6
Performance Monitors
Up tp two performance monitors allow the user to measure the activity and stall cycles for PDCA
transfers. To monitor a PDCA channel, the corresponding channel number must be written to
one of the MONnCH fields in the Performance Control Register (PCONTROL) and a one must
be written to the corresponding CHnEN bit in the same register.
Due to performance monitor hardware resource sharing, the two monitor channels should NOT
be programmed to monitor the same PDCA channel. This may result in UNDEFINED performance monitor behavior.
18.6.1
Measuring mechanisms
Three different parameters can be measured by each channel:
• The number of data transfer cycles since last channel reset, both for read and write
• The number of stall cycles since last channel reset, both for read and write
• The maximum latency since last channel reset, both for read and write
These measurements can be extracted by software and used to generate indicators for bus
latency, bus load, and maximum bus latency.
Each of the counters has a fixed width, and may therefore overflow. When an overflow is
encountered in either the Performance Channel Data Read/Write Cycle registers (PRDATAn
and PWDATAn) or the Performance Channel Read/Write Stall Cycles registers (PRSTALLn and
PWSTALLn) of a channel, all registers in the channel are reset. This behavior is altered if the
Channel Overflow Freeze bit is one in the Performance Control register (PCONTROL.CHnOVF).
If this bit is one, the channel registers are frozen when either DATA or STALL reaches its maximum value. This simplifies one-shot readout of the counter values.
The registers can also be manually reset by writing a one to the Channel Reset bit in the PCONTROL register (PCONTROL.CHnRES). The Performance Channel Read/Write Latency
registers (PRLATn and PWLATn) are saturating when their maximum count value is reached.
The PRLATn and PWLATn registers are reset only by writing a one to the CHnRES in
PCONTROL.
A counter must manually be enabled by writing a one to the Channel Enable bit in the Performance Control Register (PCONTROL.CHnEN).
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18.7
18.7.1
User Interface
Memory Map Overview
Table 18-1.
PDCA Register Memory Map
Address Range
Contents
0x000 - 0x03F
DMA channel 0 configuration registers
0x040 - 0x07F
DMA channel 1 configuration registers
...
...
(0x000 - 0x03F)+m*0x040
DMA channel m configuration registers
0x800-0x830
Performance Monitor registers
0x834
Version register
The channels are mapped as shown in Table 18-1. Each channel has a set of configuration registers, shown in Table 18-2, where n is the channel number.
18.7.2
Channel Memory Map
Table 18-2.
PDCA Channel Configuration Registers
Offset
Register
Register Name
Access
Reset
0x000 + n*0x040
Memory Address Register
MAR
Read/Write
0x00000000
0x004 + n*0x040
Peripheral Select Register
PSR
Read/Write
- (1)
0x008 + n*0x040
Transfer Counter Register
TCR
Read/Write
0x00000000
0x00C + n*0x040
Memory Address Reload Register
MARR
Read/Write
0x00000000
0x010 + n*0x040
Transfer Counter Reload Register
TCRR
Read/Write
0x00000000
0x014 + n*0x040
Control Register
CR
Write-only
0x00000000
0x018 + n*0x040
Mode Register
MR
Read/Write
0x00000000
0x01C + n*0x040
Status Register
SR
Read-only
0x00000000
0x020 + n*0x040
Interrupt Enable Register
IER
Write-only
0x00000000
0x024 + n*0x040
Interrupt Disable Register
IDR
Write-only
0x00000000
0x028 + n*0x040
Interrupt Mask Register
IMR
Read-only
0x00000000
0x02C + n*0x040
Interrupt Status Register
ISR
Read-only
0x00000000
Note:
1. The reset values are device specific. Please refer to the Module Configuration section at the
end of this chapter.
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18.7.3
Performance Monitor Memory Map
Table 18-3.
PDCA Performance Monitor Registers(1)
Offset
Register
Register Name
Access
Reset
0x800
Performance Control Register
PCONTROL
Read/Write
0x00000000
0x804
Channel0 Read Data Cycles
PRDATA0
Read-only
0x00000000
0x808
Channel0 Read Stall Cycles
PRSTALL0
Read-only
0x00000000
0x80C
Channel0 Read Max Latency
PRLAT0
Read-only
0x00000000
0x810
Channel0 Write Data Cycles
PWDATA0
Read-only
0x00000000
0x814
Channel0 Write Stall Cycles
PWSTALL0
Read-only
0x00000000
0x818
Channel0 Write Max Latency
PWLAT0
Read-only
0x00000000
0x81C
Channel1 Read Data Cycles
PRDATA1
Read-only
0x00000000
0x820
Channel1 Read Stall Cycles
PRSTALL1
Read-only
0x00000000
0x824
Channel1 Read Max Latency
PRLAT1
Read-only
0x00000000
0x828
Channel1 Write Data Cycles
PWDATA1
Read-only
0x00000000
0x82C
Channel1 Write Stall Cycles
PWSTALL1
Read-only
0x00000000
0x830
Channel1 Write Max Latency
PWLAT1
Read-only
0x00000000
Note:
18.7.4
Version Register Memory Map
Table 18-4.
Note:
1. The number of performance monitors is device specific. If the device has only one performance monitor, the Channel1 registers are not available. Please refer to the Module
Configuration section at the end of this chapter for the number of performance monitors on this
device.
PDCA Version Register Memory Map
Offset
Register
Register Name
Access
Reset
0x834
Version Register
VERSION
Read-only
- (1)
1. The reset values are device specific. Please refer to the Module Configuration section at the end of this chapter.
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18.7.5
Name:
Memory Address Register
MAR
Access Type:
Read/Write
Offset:
0x000 + n*0x040
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
18
17
16
11
10
9
8
3
2
1
0
MADDR[31:24]
23
22
21
20
19
MADDR[23:16]
15
14
13
12
MADDR[15:8]
7
6
5
4
MADDR[7:0]
• MADDR: Memory Address
Address of memory buffer. MADDR should be programmed to point to the start of the memory buffer when configuring the
PDCA. During transfer, MADDR will point to the next memory location to be read/written.
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18.7.6
Name:
Peripheral Select Register
PSR
Access Type:
Read/Write
Offset:
0x004 + n*0x040
Reset Value:
-
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
PID
• PID: Peripheral Identifier
The Peripheral Identifier selects which peripheral should be connected to the DMA channel. Writing a PID will select both which
handshake interface to use, the direction of the transfer and also the address of the Receive/Transfer Holding Register for the
peripheral. See the Module Configuration section of PDCA for details. The width of the PID field is device specific and
dependent on the number of peripheral modules in the device.
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18.7.7
Name:
Transfer Counter Register
TCR
Access Type:
Read/Write
Offset:
0x008 + n*0x040
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
3
2
1
0
TCV[15:8]
7
6
5
4
TCV[7:0]
• TCV: Transfer Counter Value
Number of data items to be transferred by the PDCA. TCV must be programmed with the total number of transfers to be made.
During transfer, TCV contains the number of remaining transfers to be done.
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18.7.8
Name:
Memory Address Reload Register
MARR
Access Type:
Read/Write
Offset:
0x00C + n*0x040
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
MARV[31:24]
23
22
21
20
MARV[23:16]
15
14
13
12
MARV[15:8]
7
6
5
4
MARV[7:0]
• MARV: Memory Address Reload Value
Reload Value for the MAR register. This value will be loaded into MAR when TCR reaches zero if the TCRR register has a nonzero value.
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18.7.9
Name:
Transfer Counter Reload Register
TCRR
Access Type:
Read/Write
Offset:
0x010 + n*0x040
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
3
2
1
0
TCRV[15:8]
7
6
5
4
TCRV[7:0]
• TCRV: Transfer Counter Reload Value
Reload value for the TCR register. When TCR reaches zero, it will be reloaded with TCRV if TCRV has a positive value. If TCRV
is zero, no more transfers will be performed for the channel. When TCR is reloaded, the TCRR register is cleared.
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18.7.10
Name:
Control Register
CR
Access Type:
Write-only
Offset:
0x014 + n*0x040
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
ECLR
7
6
5
4
3
2
1
0
-
-
-
-
-
-
TDIS
TEN
• ECLR: Transfer Error Clear
Writing a zero to this bit has no effect.
Writing a one to this bit will clear the Transfer Error bit in the Status Register (SR.TERR). Clearing the SR.TERR bit will allow the
channel to transmit data. The memory address must first be set to point to a valid location.
• TDIS: Transfer Disable
Writing a zero to this bit has no effect.
Writing a one to this bit will disable transfer for the DMA channel.
• TEN: Transfer Enable
Writing a zero to this bit has no effect.
Writing a one to this bit will enable transfer for the DMA channel.
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18.7.11
Name:
Mode Register
MR
Access Type:
Read/Write
Offset:
0x018 + n*0x040
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
SIZE
• SIZE: Size of Transfer
Table 18-5.
Size of Transfer
SIZE
Size of Transfer
0
Byte
1
Halfword
2
Word
3
Reserved
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18.7.12
Name:
Status Register
SR
Access Type:
Read-only
Offset:
0x01C + n*0x040
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
TEN
• TEN: Transfer Enabled
This bit is cleared when the TDIS bit in CR is written to one.
This bit is set when the TEN bit in CR is written to one.
0: Transfer is disabled for the DMA channel.
1: Transfer is enabled for the DMA channel.
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18.7.13
Name:
Interrupt Enable Register
IER
Access Type:
Write-only
Offset:
0x020 + n*0x040
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
TERR
TRC
RCZ
Writing a zero to a bit in this register has no effect.
Writing a one to a bit in this register will set the corresponding bit in IMR.
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18.7.14
Name:
Interrupt Disable Register
IDR
Access Type:
Write-only
Offset:
0x024 + n*0x040
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
TERR
TRC
RCZ
Writing a zero to a bit in this register has no effect.
Writing a one to a bit in this register will clear the corresponding bit in IMR.
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18.7.15
Name:
Interrupt Mask Register
IMR
Access Type:
Read-only
Offset:
0x028 + n*0x040
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
TERR
TRC
RCZ
0: The corresponding interrupt is disabled.
1: The corresponding interrupt is enabled.
A bit in this register is cleared when the corresponding bit in IDR is written to one.
A bit in this register is set when the corresponding bit in IER is written to one.
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18.7.16
Name:
Interrupt Status Register
ISR
Access Type:
Read-only
Offset:
0x02C + n*0x040
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
TERR
TRC
RCZ
• TERR: Transfer Error
This bit is cleared when no transfer errors have occurred since the last write to CR.ECLR.
This bit is set when one or more transfer errors has occurred since reset or the last write to CR.ECLR.
• TRC: Transfer Complete
This bit is cleared when the TCR and/or the TCRR holds a non-zero value.
This bit is set when both the TCR and the TCRR are zero.
• RCZ: Reload Counter Zero
This bit is cleared when the TCRR holds a non-zero value.
This bit is set when TCRR is zero.
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18.7.17
Name:
Performance Control Register
PCONTROL
Access Type:
Read/Write
Offset:
0x800
Reset Value:
0x00000000
31
30
29
28
-
-
23
22
-
-
15
14
13
12
-
-
-
7
6
-
-
27
26
25
24
18
17
16
11
10
9
8
-
-
-
CH1RES
CH0RES
5
4
3
2
1
0
CH1OF
CH0OF
-
-
CH1EN
CH0EN
MON1CH
21
20
19
MON0CH
• MON1CH: Performance Monitor Channel 1
• MON0CH: Performance Monitor Channel 0
The PDCA channel number to monitor with counter n
Due to performance monitor hardware resource sharing, the two performance monitor channels should NOT be programmed to
monitor the same PDCA channel. This may result in UNDEFINED monitor behavior.
• CH1RES: Performance Channel 1 Counter Reset
Writing a zero to this bit has no effect.
Writing a one to this bit will reset the counter in performance channel 1.
This bit always reads as zero.
• CH0RES: Performance Channel 0 Counter Reset
Writing a zero to this bit has no effect.
Writing a one to this bit will reset the counter in performance channel 0.
This bit always reads as zero.
• CH1OF: Performance Channel 1 Overflow Freeze
0: The performance channel registers are reset if DATA or STALL overflows.
1: All performance channel registers are frozen just before DATA or STALL overflows.
• CH1OF: Performance Channel 0 Overflow Freeze
0: The performance channel registers are reset if DATA or STALL overflows.
1: All performance channel registers are frozen just before DATA or STALL overflows.
• CH1EN: Performance Channel 1 Enable
0: Performance channel 1 is disabled.
1: Performance channel 1 is enabled.
• CH0EN: Performance Channel 0 Enable
0: Performance channel 0 is disabled.
1: Performance channel 0 is enabled.
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18.7.18
Name:
Performance Channel 0 Read Data Cycles
PRDATA0
Access Type:
Read-only
Offset:
0x804
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
DATA[31:24]
23
22
21
20
DATA[23:16]
15
14
13
12
DATA[15:8]
7
6
5
4
DATA[7:0]
• DATA: Data Cycles Counted Since Last Reset
Clock cycles are counted using the CLK_PDCA_HSB clock
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18.7.19
Name:
Performance Channel 0 Read Stall Cycles
PRSTALL0
Access Type:
Read-only
Offset:
0x808
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
STALL[31:24]
23
22
21
20
STALL[23:16]
15
14
13
12
STALL[15:8]
7
6
5
4
STALL[7:0]
• STALL: Stall Cycles Counted Since Last Reset
Clock cycles are counted using the CLK_PDCA_HSB clock
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18.7.20
Name:
Performance Channel 0 Read Max Latency
PRLAT0
Access Type:
Read/Write
Offset:
0x80C
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
3
2
1
0
LAT[15:8]
7
6
5
4
LAT[7:0]
• LAT: Maximum Transfer Initiation Cycles Counted Since Last Reset
Clock cycles are counted using the CLK_PDCA_HSB clock
This counter is saturating. The register is reset only when PCONTROL.CH0RES is written to one.
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18.7.21
Name:
Performance Channel 0 Write Data Cycles
PWDATA0
Access Type:
Read-only
Offset:
0x810
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
DATA[31:24]
23
22
21
20
DATA[23:16]
15
14
13
12
DATA[15:8]
7
6
5
4
DATA[7:0]
• DATA: Data Cycles Counted Since Last Reset
Clock cycles are counted using the CLK_PDCA_HSB clock
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18.7.22
Name:
Performance Channel 0 Write Stall Cycles
PWSTALL0
Access Type:
Read-only
Offset:
0x814
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
STALL[31:24]
23
22
21
20
STALL[23:16]
15
14
13
12
STALL[15:8]
7
6
5
4
STALL[7:0]
• STALL: Stall Cycles Counted Since Last Reset
Clock cycles are counted using the CLK_PDCA_HSB clock
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18.7.23
Name:
Performance Channel 0 Write Max Latency
PWLAT0
Access Type:
Read/Write
Offset:
0x818
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
3
2
1
0
LAT[15:8]
7
6
5
4
LAT[7:0]
• LAT: Maximum Transfer Initiation Cycles Counted Since Last Reset
Clock cycles are counted using the CLK_PDCA_HSB clock
This counter is saturating. The register is reset only when PCONTROL.CH0RES is written to one.
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18.7.24
Name:
Performance Channel 1 Read Data Cycles
PRDATA1
Access Type:
Read-only
Offset:
0x81C
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
DATA[31:24]
23
22
21
20
DATA[23:16]
15
14
13
12
DATA[15:8]
7
6
5
4
DATA[7:0]
• DATA: Data Cycles Counted Since Last Reset
Clock cycles are counted using the CLK_PDCA_HSB clock
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18.7.25
Name:
Performance Channel 1 Read Stall Cycles
PRSTALL1
Access Type:
Read-only
Offset:
0x820
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
STALL[31:24]
23
22
21
20
STALL[23:16]
15
14
13
12
STALL[15:8]
7
6
5
4
STALL[7:0]
• STALL: Stall Cycles Counted Since Last Reset
Clock cycles are counted using the CLK_PDCA_HSB clock
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18.7.26
Name:
Performance Channel 1 Read Max Latency
PLATR1
Access Type:
Read/Write
Offset:
0x824
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
3
2
1
0
LAT[15:8]
7
6
5
4
LAT[7:0]
• LAT: Maximum Transfer Initiation Cycles Counted Since Last Reset
Clock cycles are counted using the CLK_PDCA_HSB clock
This counter is saturating. The register is reset only when PCONTROL.CH1RES is written to one.
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18.7.27
Name:
Performance Channel 1 Write Data Cycles
PWDATA1
Access Type:
Read-only
Offset:
0x828
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
DATA[31:24]
23
22
21
20
DATA[23:16]
15
14
13
12
DATA[15:8]
7
6
5
4
DATA[7:0]
• DATA: Data Cycles Counted Since Last Reset
Clock cycles are counted using the CLK_PDCA_HSB clock
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18.7.28
Name:
Performance Channel 1 Write Stall Cycles
PWSTALL1
Access Type:
Read-only
Offset:
0x82C
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
STALL[31:24]
23
22
21
20
STALL[23:16]
15
14
13
12
STALL[15:8]
7
6
5
4
STALL[7:0]
• STALL: Stall Cycles Counted Since Last Reset
Clock cycles are counted using the CLK_PDCA_HSB clock
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18.7.29
Name:
Performance Channel 1 Write Max Latency
PWLAT1
Access Type:
Read/Write
Offset:
0x830
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
3
2
1
0
LAT[15:8]
7
6
5
4
LAT[7:0]
• LAT: Maximum Transfer Initiation Cycles Counted Since Last Reset
Clock cycles are counted using the CLK_PDCA_HSB clock
This counter is saturating. The register is reset only when PCONTROL.CH1RES is written to one.
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18.7.30
Name:
PDCA Version Register
VERSION
Access Type:
Read-only
Offset:
0x834
Reset Value:
-
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
15
14
13
12
9
8
-
-
-
-
7
6
5
4
VARIANT
11
10
VERSION[11:8]
3
2
1
0
VERSION[7:0]
• VARIANT: Variant Number
Reserved. No functionality associated.
• VERSION: Version Number
Version number of the module. No functionality associated.
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18.8
Module Configuration
The specific configuration for the PDCA instance is listed in the following tables.
Table 18-6.
Features
PDCA
Number of channels
8
Table 18-7.
18.8.1
PDCA Configuration
Register Reset Values
Register
Reset Value
PSRn
n
VERSION
0x00000110
DMA Handshake Signals
The following table defines the valid settings for the Peripheral Identifier (PID) in the PDCA
Peripheral Select Register (PSR).).
Table 18-8.
PDCA Handshake Signals
PID Value
Peripheral module & direction
0
ADC - RX
1
SSC - RX
2
USART0 - RX
3
USART1 - RX
4
USART2 - RX
5
USART3 - RX
6
TWIM0 - RX
7
TWIM1 - RX
8
TWIS0 - RX
9
TWIS1 - RX
10
SPI0 - RX
11
SPI1 - RX
12
SSC - TX
13
USART0 - TX
14
USART1 - TX
15
USART2 - TX
16
USART3 - TX
17
TWIM0 - TX
18
TWIM1 - TX
19
TWIS0 - TX
20
TWIS1 - TX
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Table 18-8.
PDCA Handshake Signals
PID Value
Peripheral module & direction
21
SPI0 - TX
22
SPI1 - TX
23
ABDAC - TX
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19. DMA Controller (DMACA)
Rev: 2.0.6.6
19.1
Features
• 2 HSB Master Interfaces
• Channels
• Software and Hardware Handshaking Interfaces
– 11 Hardware Handshaking Interfaces
• Memory/Non-Memory Peripherals to Memory/Non-Memory Peripherals Transfer
• Single-block DMA Transfer
• Multi-block DMA Transfer
– Linked Lists
– Auto-Reloading
– Contiguous Blocks
• DMA Controller is Always the Flow Controller
• Additional Features
– Scatter and Gather Operations
– Channel Locking
– Bus Locking
– FIFO Mode
– Pseudo Fly-by Operation
19.2
Overview
The DMA Controller (DMACA) is an HSB-central DMA controller core that transfers data from a
source peripheral to a destination peripheral over one or more System Bus. One channel is
required for each source/destination pair. In the most basic configuration, the DMACA has one
master interface and one channel. The master interface reads the data from a source and writes
it to a destination. Two System Bus transfers are required for each DMA data transfer. This is
also known as a dual-access transfer.
The DMACA is programmed via the HSB slave interface.
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19.3
Block Diagram
Figure 19-1. DMA Controller (DMACA) Block Diagram
DMA Controller
HSB Slave
HSB Slave
I/F
Interrupt
Generator
CFG
irq_dma
Channel 1
Channel 0
FIFO
HSB Master
HSB Master
I/F
SRC
FSM
19.4
DST
FSM
Product Dependencies
In order to use this module, other parts of the system must be configured correctly, as described
below.
19.4.1
I/O Lines
The pins used for interfacing the compliant external devices may be multiplexed with GPIO lines.
The user must first program the GPIO controller to assign the DMACA pins to their peripheral
functions.
19.4.2
Power Management
To prevent bus errors the DMACA operation must be terminated before entering sleep mode.
19.4.3
Clocks
The CLK_DMACA to the DMACA is generated by the Power Manager (PM). Before using the
DMACA, the user must ensure that the DMACA clock is enabled in the power manager.
19.4.4
Interrupts
The DMACA interface has an interrupt line connected to the Interrupt Controller. Handling the
DMACA interrupt requires programming the interrupt controller before configuring the DMACA.
19.4.5
Peripherals
Both the source peripheral and the destination peripheral must be set up correctly prior to the
DMA transfer.
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19.5
19.5.1
Functional Description
Basic Definitions
Source peripheral: Device on a System Bus layer from where the DMACA reads data, which is
then stored in the channel FIFO. The source peripheral teams up with a destination peripheral to
form a channel.
Destination peripheral: Device to which the DMACA writes the stored data from the FIFO (previously read from the source peripheral).
Memory: Source or destination that is always “ready” for a DMA transfer and does not require a
handshaking interface to interact with the DMACA. A peripheral should be assigned as memory
only if it does not insert more than 16 wait states. If more than 16 wait states are required, then
the peripheral should use a handshaking interface (the default if the peripheral is not programmed to be memory) in order to signal when it is ready to accept or supply data.
Channel: Read/write datapath between a source peripheral on one configured System Bus
layer and a destination peripheral on the same or different System Bus layer that occurs through
the channel FIFO. If the source peripheral is not memory, then a source handshaking interface
is assigned to the channel. If the destination peripheral is not memory, then a destination handshaking interface is assigned to the channel. Source and destination handshaking interfaces can
be assigned dynamically by programming the channel registers.
Master interface: DMACA is a master on the HSB bus reading data from the source and writing
it to the destination over the HSB bus.
Slave interface: The HSB interface over which the DMACA is programmed. The slave interface
in practice could be on the same layer as any of the master interfaces or on a separate layer.
Handshaking interface: A set of signal registers that conform to a protocol and handshake
between the DMACA and source or destination peripheral to control the transfer of a single or
burst transaction between them. This interface is used to request, acknowledge, and control a
DMACA transaction. A channel can receive a request through one of three types of handshaking
interface: hardware, software, or peripheral interrupt.
Hardware handshaking interface: Uses hardware signals to control the transfer of a single or
burst transaction between the DMACA and the source or destination peripheral.
Software handshaking interface: Uses software registers to control the transfer of a single or
burst transaction between the DMACA and the source or destination peripheral. No special
DMACA handshaking signals are needed on the I/O of the peripheral. This mode is useful for
interfacing an existing peripheral to the DMACA without modifying it.
Peripheral interrupt handshaking interface: A simple use of the hardware handshaking interface. In this mode, the interrupt line from the peripheral is tied to the dma_req input of the
hardware handshaking interface. Other interface signals are ignored.
Flow controller: The device (either the DMACA or source/destination peripheral) that determines the length of and terminates a DMA block transfer. If the length of a block is known before
enabling the channel, then the DMACA should be programmed as the flow controller. If the
length of a block is not known prior to enabling the channel, the source or destination peripheral
needs to terminate a block transfer. In this mode, the peripheral is the flow controller.
Flow control mode (CFGx.FCMODE): Special mode that only applies when the destination
peripheral is the flow controller. It controls the pre-fetching of data from the source peripheral.
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Transfer hierarchy: Figure 19-2 on page 316 illustrates the hierarchy between DMACA transfers, block transfers, transactions (single or burst), and System Bus transfers (single or burst) for
non-memory peripherals. Figure 19-3 on page 316 shows the transfer hierarchy for memory.
Figure 19-2. DMACA Transfer Hierarchy for Non-Memory Peripheral
DMAC Transfer
Block
Block
Burst
Transaction
System Bus
Burst
Transfer
DMA Transfer
Level
Block Transfer
Level
Block
Burst
Transaction
Burst
Transaction
System Bus
Burst
Transfer
System Bus
Burst
Transfer
System Bus
Single
Transfer
Single
Transaction
DMA Transaction
Level
System Bus
Single
Transfer
System Bus
Transfer Level
Figure 19-3. DMACA Transfer Hierarchy for Memory
DMA Transfer
Level
DMAC Transfer
Block
System Bus
Burst
Transfer
Block
System Bus
Burst
Transfer
Block
System Bus
Burst
Transfer
System Bus
Single
Transfer
Block Transfer
Level
System Bus
Transfer Level
Block: A block of DMACA data. The amount of data (block length) is determined by the flow
controller. For transfers between the DMACA and memory, a block is broken directly into a
sequence of System Bus bursts and single transfers. For transfers between the DMACA and a
non-memory peripheral, a block is broken into a sequence of DMACA transactions (single and
bursts). These are in turn broken into a sequence of System Bus transfers.
Transaction: A basic unit of a DMACA transfer as determined by either the hardware or software handshaking interface. A transaction is only relevant for transfers between the DMACA
and a source or destination peripheral if the source or destination peripheral is a non-memory
device. There are two types of transactions: single and burst.
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– Single transaction: The length of a single transaction is always 1 and is converted
to a single System Bus transfer.
– Burst transaction: The length of a burst transaction is programmed into the
DMACA. The burst transaction is converted into a sequence of System Bus bursts
and single transfers. DMACA executes each burst transfer by performing
incremental bursts that are no longer than the maximum System Bus burst size set.
The burst transaction length is under program control and normally bears some
relationship to the FIFO sizes in the DMACA and in the source and destination
peripherals.
DMA transfer: Software controls the number of blocks in a DMACA transfer. Once the DMA
transfer has completed, then hardware within the DMACA disables the channel and can generate an interrupt to signal the completion of the DMA transfer. You can then re-program the
channel for a new DMA transfer.
Single-block DMA transfer: Consists of a single block.
Multi-block DMA transfer: A DMA transfer may consist of multiple DMACA blocks. Multi-block
DMA transfers are supported through block chaining (linked list pointers), auto-reloading of
channel registers, and contiguous blocks. The source and destination can independently select
which method to use.
– Linked lists (block chaining) – A linked list pointer (LLP) points to the location in
system memory where the next linked list item (LLI) exists. The LLI is a set of
registers that describe the next block (block descriptor) and an LLP register. The
DMACA fetches the LLI at the beginning of every block when block chaining is
enabled.
– Auto-reloading – The DMACA automatically reloads the channel registers at the
end of each block to the value when the channel was first enabled.
– Contiguous blocks – Where the address between successive blocks is selected to
be a continuation from the end of the previous block.
Scatter: Relevant to destination transfers within a block. The destination System Bus address is
incremented or decremented by a programmed amount -the scatter increment- when a scatter
boundary is reached. The destination System Bus address is incremented or decremented by
the value stored in the destination scatter increment (DSRx.DSI) field, multiplied by the number
of bytes in a single HSB transfer to the destination (decoded value of CTLx.DST_TR_WIDTH)/8.
The number of destination transfers between successive scatter boundaries is programmed into
the Destination Scatter Count (DSC) field of the DSRx register.
Scatter is enabled by writing a ‘1’ to the CTLx.DST_SCATTER_EN bit. The CTLx.DINC field
determines if the address is incremented, decremented or remains fixed when a scatter boundary is reached. If the CTLx.DINC field indicates a fixed-address control throughout a DMA
transfer, then the CTLx.DST_SCATTER_EN bit is ignored, and the scatter feature is automatically disabled.
Gather: Relevant to source transfers within a block. The source System Bus address is incremented or decremented by a programmed amount when a gather boundary is reached. The
number of System Bus transfers between successive gather boundaries is programmed into the
Source Gather Count (SGRx.SGC) field. The source address is incremented or decremented by
the value stored in the source gather increment (SGRx.SGI) field multiplied by the number of
bytes in a single HSB transfer from the source -(decoded value of CTLx.SRC_TR_WIDTH)/8 when a gather boundary is reached.
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Gather is enabled by writing a ‘1’ to the CTLx.SRC_GATHER_EN bit. The CTLx.SINC field
determines if the address is incremented, decremented or remains fixed when a gather boundary is reached. If the CTLx.SINC field indicates a fixed-address control throughout a DMA
transfer, then the CTLx.SRC_GATHER_EN bit is ignored and the gather feature is automatically
disabled.
Note: For multi-block transfers, the counters that keep track of the number of transfer left to
reach a gather/scatter boundary are re-initialized to the source gather count (SGRx.SGC) and
destination scatter count (DSRx.DSC), respectively, at the start of each block transfer.
Figure 19-4. Destination Scatter Transfer
System Memory
D11
A0 + 0x218
A0 + 0x210
A0 + 0x208
A0 + 0x200
Scatter Boundary A0 + 0x220
d11
D10
D9
D8
d8
Data Stream
Scatter Increment
d0 d1 d2 d3 d4 d5 d6 d7 d8 d9 d10 d11
0 x 080
A0 + 0x118
A0 + 0x110
A0 + 0x108
A0 + 0x100
Scatter Boundary A0 + 0x120
D7
D6
D5
d7
d4
D4
Scatter Increment
0 x 080
A0 + 0x018
A0 + 0x010
A0 + 0x008
A0
D3
d3
D2
D1
D0
d0
Scatter Boundary A0 + 0x020
CTLx.DST_TR_WIDTH = 3'b011 (64bit/8 = 8 bytes)
DSR.DSI = 16
DSR.DSC = 4
DSR.DSI * 8 = 0x80 (Scatter Increment in bytes)
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Figure 19-5. Source Gather Transfer
System Memory
D11
A0 + 0x034
A0 + 0x030
A0 + 0x02C
A0 + 0x028
d11
D10
D9
D8
d8
A0 + 0x018
A0 + 0x014
D7
Data Stream
d0 d1 d2 d3 d4 d5 d6 d7 d8 d9 d10 d11
A0 + 0x020
A0 + 0x01C
Gather Boundary A0 + 0x38
Gather Increment = 4
d7
Gather Boundary A0 + 0x24
Gather Increment = 4
D6
D5
d4
D4
A0 + 0x00C
A0 + 0x008
A0 + 0x004
A0
D3
d3
Gather Boundary A0 + 0x10
Gather Increment = 4
D2
D1
D0
d0
CTLx.SRC_TR_WIDTH = 3'b010 (32bit/8 = 4 bytes)
SGR.SGI = 1
SGR.SGC = 4
SGR.SGI * 4 = 0x4 (Gather Increment in bytes)
Channel locking: Software can program a channel to keep the HSB master interface by locking
the arbitration for the master bus interface for the duration of a DMA transfer, block, or transaction (single or burst).
Bus locking: Software can program a channel to maintain control of the System Bus bus by
asserting hlock for the duration of a DMA transfer, block, or transaction (single or burst). Channel locking is asserted for the duration of bus locking at a minimum.
FIFO mode: Special mode to improve bandwidth. When enabled, the channel waits until the
FIFO is less than half full to fetch the data from the source peripheral and waits until the FIFO is
greater than or equal to half full to send data to the destination peripheral. Thus, the channel can
transfer the data using System Bus bursts, eliminating the need to arbitrate for the HSB master
interface for each single System Bus transfer. When this mode is not enabled, the channel only
waits until the FIFO can transmit/accept a single System Bus transfer before requesting the
master bus interface.
Pseudo fly-by operation: Typically, it takes two System Bus cycles to complete a transfer, one
for reading the source and one for writing to the destination. However, when the source and destination peripherals of a DMA transfer are on different System Bus layers, it is possible for the
DMACA to fetch data from the source and store it in the channel FIFO at the same time as the
DMACA extracts data from the channel FIFO and writes it to the destination peripheral. This
activity is known as pseudo fly-by operation. For this to occur, the master interface for both
source and destination layers must win arbitration of their HSB layer. Similarly, the source and
destination peripherals must win ownership of their respective master interfaces.
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19.6
Arbitration for HSB Master Interface
Each DMACA channel has two request lines that request ownership of a particular master bus
interface: channel source and channel destination request lines.
Source and destination arbitrate separately for the bus. Once a source/destination state
machine gains ownership of the master bus interface and the master bus interface has ownership of the HSB bus, then HSB transfers can proceed between the peripheral and the DMACA.
An arbitration scheme decides which of the request lines (2 * DMAH_NUM_CHANNELS) is
granted the particular master bus interface. Each channel has a programmable priority. A
request for the master bus interface can be made at any time, but is granted only after the current HSB transfer (burst or single) has completed. Therefore, if the master interface is
transferring data for a lower priority channel and a higher priority channel requests service, then
the master interface will complete the current burst for the lower priority channel before switching to transfer data for the higher priority channel.
If only one request line is active at the highest priority level, then the request with the highest priority wins ownership of the HSB master bus interface; it is not necessary for the priority levels to
be unique.
If more than one request is active at the highest requesting priority, then these competing
requests proceed to a second tier of arbitration:
If equal priority requests occur, then the lower-numbered channel is granted.
In other words, if a peripheral request attached to Channel 7 and a peripheral request attached
to Channel 8 have the same priority, then the peripheral attached to Channel 7 is granted first.
19.7
Memory Peripherals
Figure 19-3 on page 316 shows the DMA transfer hierarchy of the DMACA for a memory peripheral. There is no handshaking interface with the DMACA, and therefore the memory peripheral
can never be a flow controller. Once the channel is enabled, the transfer proceeds immediately
without waiting for a transaction request. The alternative to not having a transaction-level handshaking interface is to allow the DMACA to attempt System Bus transfers to the peripheral once
the channel is enabled. If the peripheral slave cannot accept these System Bus transfers, it
inserts wait states onto the bus until it is ready; it is not recommended that more than 16 wait
states be inserted onto the bus. By using the handshaking interface, the peripheral can signal to
the DMACA that it is ready to transmit/receive data, and then the DMACA can access the
peripheral without the peripheral inserting wait states onto the bus.
19.8
Handshaking Interface
Handshaking interfaces are used at the transaction level to control the flow of single or burst
transactions. The operation of the handshaking interface is different and depends on whether
the peripheral or the DMACA is the flow controller.
The peripheral uses the handshaking interface to indicate to the DMACA that it is ready to transfer/accept data over the System Bus. A non-memory peripheral can request a DMA transfer
through the DMACA using one of two handshaking interfaces:
• Hardware handshaking
• Software handshaking
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Software selects between the hardware or software handshaking interface on a per-channel
basis. Software handshaking is accomplished through memory-mapped registers, while hardware handshaking is accomplished using a dedicated handshaking interface.
19.8.1
Software Handshaking
When the slave peripheral requires the DMACA to perform a DMA transaction, it communicates
this request by sending an interrupt to the CPU or interrupt controller.
The interrupt service routine then uses the software registers to initiate and control a DMA transaction. These software registers are used to implement the software handshaking interface.
The HS_SEL_SRC/HS_SEL_DST bit in the CFGx channel configuration register must be set to
enable software handshaking.
When the peripheral is not the flow controller, then the last transaction registers LstSrcReg and
LstDstReg are not used, and the values in these registers are ignored.
19.8.1.1
Burst Transactions
Writing a 1 to the ReqSrcReg[x]/ReqDstReg[x] register is always interpreted as a burst transaction request, where x is the channel number. However, in order for a burst transaction request to
start, software must write a 1 to the SglReqSrcReg[x]/SglReqDstReg[x] register.
You can write a 1 to the SglReqSrcReg[x]/SglReqDstReg[x] and ReqSrcReg[x]/ReqDstReg[x]
registers in any order, but both registers must be asserted in order to initiate a burst transaction.
Upon completion of the burst transaction, the hardware clears the SglReqSrcReg[x]/SglReqDstReg[x] and ReqSrcReg[x]/ReqDstReg[x] registers.
19.8.1.2
Single Transactions
Writing a 1 to the SglReqSrcReg/SglReqDstReg initiates a single transaction. Upon completion
of the single transaction, both the SglReqSrcReg/SglReqDstReg and ReqSrcReg/ReqDstReg
bits are cleared by hardware. Therefore, writing a 1 to the ReqSrcReg/ReqDstReg is ignored
while a single transaction has been initiated, and the requested burst transaction is not serviced.
Again, writing a 1 to the ReqSrcReg/ReqDstReg register is always a burst transaction request.
However, in order for a burst transaction request to start, the corresponding channel bit in the
SglReqSrcReg/SglReqDstReg must be asserted. Therefore, to ensure that a burst transaction is
serviced, you must write a 1 to the ReqSrcReg/ReqDstReg before writing a 1 to the SglReqSrcReg/SglReqDstReg register.
Software can poll the relevant channel bit in the SglReqSrcReg/ SglReqDstReg and ReqSrcReg/ReqDstReg registers. When both are 0, then either the requested burst or single
transaction has completed. Alternatively, the IntSrcTran or IntDstTran interrupts can be enabled
and unmasked in order to generate an interrupt when the requested source or destination transaction has completed.
Note:
19.8.2
The transaction-complete interrupts are triggered when both single and burst transactions are
complete. The same transaction-complete interrupt is used for both single and burst transactions.
Hardware Handshaking
There are 11 hardware handshaking interfaces between the DMACA and peripherals. Refer to
the module configuration chapter for the device-specific mapping of these interfaces.
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19.8.2.1
External DMA Request Definition
When an external slave peripheral requires the DMACA to perform DMA transactions, it communicates its request by asserting the external nDMAREQx signal. This signal is resynchronized to
ensure a proper functionality (see ”External DMA Request Timing” on page 322).
The external nDMAREQx signal should be asserted when the source threshold level is reached.
After resynchronization, the rising edge of dma_req starts the transfer. An external DMAACKx
acknowledge signal is also provided to indicate when the DMA transfer has completed. The
peripheral should de-assert the DMA request signal when DMAACKx is asserted.
The external nDMAREQx signal must be de-asserted after the last transfer and re-asserted
again before a new transaction starts.
For a source FIFO, an active edge should be triggered on nDMAREQx when the source FIFO
exceeds a watermark level. For a destination FIFO, an active edge should be triggered on
nDMAREQx when the destination FIFO drops below the watermark level.
The source transaction length, CTLx.SRC_MSIZE, and destination transaction length,
CTLx.DEST_MSIZE, must be set according to watermark levels on the source/destination
peripherals.
Figure 19-6. External DMA Request Timing
Hclk
DMA Transaction
nDMAREQx
dma_req
DMA Transfers
DMA Transfers
DMA Transfers
dma_ack
19.9
DMACA Transfer Types
A DMA transfer may consist of single or multi-block transfers. On successive blocks of a multiblock transfer, the SARx/DARx register in the DMACA is reprogrammed using either of the following methods:
• Block chaining using linked lists
• Auto-reloading
• Contiguous address between blocks
On successive blocks of a multi-block transfer, the CTLx register in the DMACA is re-programmed using either of the following methods:
• Block chaining using linked lists
• Auto-reloading
When block chaining, using linked lists is the multi-block method of choice, and on successive
blocks, the LLPx register in the DMACA is re-programmed using the following method:
• Block chaining using linked lists
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A block descriptor (LLI) consists of following registers, SARx, DARx, LLPx, CTL. These registers, along with the CFGx register, are used by the DMACA to set up and describe the block
transfer.
19.9.1
19.9.1.1
Multi-block Transfers
Block Chaining Using Linked Lists
In this case, the DMACA re-programs the channel registers prior to the start of each block by
fetching the block descriptor for that block from system memory. This is known as an LLI update.
DMACA block chaining is supported by using a Linked List Pointer register (LLPx) that stores the
address in memory of the next linked list item. Each LLI (block descriptor) contains the corresponding block descriptor (SARx, DARx, LLPx, CTLx).
To set up block chaining, a sequence of linked lists must be programmed in memory.
The SARx, DARx, LLPx and CTLx registers are fetched from system memory on an LLI update.
The updated contents of the CTLx register are written back to memory on block completion. Figure 19-7 on page 323 shows how to use chained linked lists in memory to define multi-block
transfers using block chaining.
The Linked List multi-block transfers is initiated by programming LLPx with LLPx(0) (LLI(0) base
address) and CTLx with CTLx.LLP_S_EN and CTLx.LLP_D_EN.
Figure 19-7. Multi-block Transfer Using Linked Lists
LLI(0)
LLPx(0)
System Memory
LLI(1)
CTLx[63..32]
CTLx[63..32]
CTLx[31..0]
CTLx[31..0]
LLPx(1)
LLPx(2)
DARx
DARx
SARx
SARx
LLPx(2)
LLPx(1)
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Table 19-1.
Programming of Transfer Types and Channel Register Update Method (DMACA State Machine Table)
LLP.
LLP_S_EN
RELOAD
_SR
LLP_D_EN
RELOAD_
DS
CTLx,
LLPx
LOC
(
CFGx)
(
CTLx)
(
CFGx)
Update
=0
(
CTLx)
1) Single Block or
last transfer of
multi-Block
Yes
0
0
0
0
2) Auto Reload
multi-block transfer
with contiguous
SAR
Yes
0
0
0
3) Auto Reload
multi-block transfer
with contiguous
DAR
Yes
0
1
4) Auto Reload
multi-block transfer
Yes
0
5) Single Block or
last transfer of
multi-block
No
0
Transfer Type
6) Linked List
multi-block transfer
with contiguous
SAR
7) Linked List
multi-block transfer
with auto-reload
SAR
8) Linked List
multi-block transfer
with contiguous
DAR
9) Linked List
multi-block transfer
with auto-reload
DAR
10) Linked List
multi-block transfer
No
No
No
No
No
0
0
1
1
1
SARx
Update
Method
DARx
Update
Method
None, user
reprograms
None (single)
None
(single)
No
1
CTLx,LLPx are
reloaded from
initial values.
Contiguous
AutoReload
No
0
0
CTLx,LLPx are
reloaded from
initial values.
Auto-Reload
Contiguous
No
1
0
1
CTLx,LLPx are
reloaded from
initial values.
Auto-Reload
AutoReload
No
0
0
0
None, user
reprograms
None (single)
None
(single)
Yes
0
CTLx,LLPx
loaded from
next Linked List
item
Contiguous
Linked
List
Yes
0
CTLx,LLPx
loaded from
next Linked List
item
Auto-Reload
Linked
List
Yes
0
CTLx,LLPx
loaded from
next Linked List
item
Linked List
Contiguous
Yes
1
CTLx,LLPx
loaded from
next Linked List
item
Linked List
AutoReload
Yes
0
CTLx,LLPx
loaded from
next Linked List
item
Linked List
Linked
List
Yes
0
1
0
0
0
1
1
0
0
1
Method
Write
Back
19.9.1.2
Auto-reloading of Channel Registers
During auto-reloading, the channel registers are reloaded with their initial values at the completion of each block and the new values used for the new block. Depending on the row number in
Table 19-1 on page 324, some or all of the SARx, DARx and CTLx channel registers are
reloaded from their initial value at the start of a block transfer.
19.9.1.3
Contiguous Address Between Blocks
In this case, the address between successive blocks is selected to be a continuation from the
end of the previous block. Enabling the source or destination address to be contiguous between
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blocks is a function of CTLx.LLP_S_EN, CFGx.RELOAD_SR, CTLx.LLP_D_EN, and
CFGx.RELOAD_DS registers (see Figure 19-1 on page 314).
Note:
19.9.1.4
Both SARx and DARx updates cannot be selected to be contiguous. If this functionality is
required, the size of the Block Transfer (CTLx.BLOCK_TS) must be increased. If this is at the maximum value, use Row 10 of Table 19-1 on page 324 and setup the LLI.SARx address of the
block descriptor to be equal to the end SARx address of the previous block. Similarly, setup the
LLI.DARx address of the block descriptor to be equal to the end DARx address of the previous
block.
Suspension of Transfers Between Blocks
At the end of every block transfer, an end of block interrupt is asserted if:
• interrupts are enabled, CTLx.INT_EN = 1
• the channel block interrupt is unmasked, MaskBlock[n] = 0, where n is the channel number.
Note:
The block complete interrupt is generated at the completion of the block transfer to the destination.
For rows 6, 8, and 10 of Table 19-1 on page 324, the DMA transfer does not stall between block
transfers. For example, at the end of block N, the DMACA automatically proceeds to block N + 1.
For rows 2, 3, 4, 7, and 9 of Table 19-1 on page 324 (SARx and/or DARx auto-reloaded between
block transfers), the DMA transfer automatically stalls after the end of block. Interrupt is asserted
if the end of block interrupt is enabled and unmasked.
The DMACA does not proceed to the next block transfer until a write to the block interrupt clear
register, ClearBlock[n], is performed by software. This clears the channel block complete
interrupt.
For rows 2, 3, 4, 7, and 9 of Table 19-1 on page 324 (SARx and/or DARx auto-reloaded between
block transfers), the DMA transfer does not stall if either:
• interrupts are disabled, CTLx.INT_EN = 0, or
• the channel block interrupt is masked, MaskBlock[n] = 1, where n is the channel number.
Channel suspension between blocks is used to ensure that the end of block ISR (interrupt service routine) of the next-to-last block is serviced before the start of the final block commences.
This ensures that the ISR has cleared the CFGx.RELOAD_SR and/or CFGx.RELOAD_DS bits
b efo re co mp let ion of t he fina l blo ck. Th e r elo ad bit s CFGx .REL OAD _SR a nd /o r
CFGx.RELOAD_DS should be cleared in the ‘end of block ISR’ for the next-to-last block
transfer.
19.9.2
Ending Multi-block Transfers
All multi-block transfers must end as shown in either Row 1 or Row 5 of Table 19-1 on page 324.
At the end of every block transfer, the DMACA samples the row number, and if the DMACA is in
Row 1 or Row 5 state, then the previous block transferred was the last block and the DMA transfer is terminated.
Note:
Row 1 and Row 5 are used for single block transfers or terminating multiblock transfers. Ending in
Row 5 state enables status fetch for the last block. Ending in Row 1 state disables status fetch for
the last block.
For rows 2,3 and 4 of Table 19-1 on page 324, (LLPx = 0 and CFGx.RELOAD_SR and/or
CFGx.RELOAD_DS is set), multi-block DMA transfers continue until both the
CFGx.RELOAD_SR and CFGx.RELOAD_DS registers are cleared by software. They should be
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programmed to zero in the end of block interrupt service routine that services the next-to-last
block transfer. This puts the DMACA into Row 1 state.
For rows 6, 8, and 10 (both CFGx.RELOAD_SR and CFGx.RELOAD_DS cleared) the user must
setup the last block descriptor in memory such that both LLI.CTLx.LLP_S_EN and
LLI.CTLx.LLP_D_EN are zero. If the LLI.LLPx register of the last block descriptor in memory is
non-zero, then the DMA transfer is terminated in Row 5. If the LLI.LLPx register of the last block
descriptor in memory is zero, then the DMA transfer is terminated in Row 1.
For rows 7 and 9, the end-of-block interrupt service routine that services the next-to-last block
transfer should clear the CFGx.RELOAD_SR and CFGx.RELOAD_DS reload bits. The last
block descriptor in memory should be set up so that both the LLI.CTLx.LLP_S_EN and
LLI.CTLx.LLP_D_EN are zero. If the LLI.LLPx register of the last block descriptor in memory is
non-zero, then the DMA transfer is terminated in Row 5. If the LLI.LLPx register of the last block
descriptor in memory is zero, then the DMA transfer is terminated in Row 1.
The only allowed transitions between the rows of Table 19-1 on page 324are from any row into
row 1 or row 5. As already stated, a transition into row 1 or row 5 is used to terminate the DMA
transfer. All other transitions between rows are not allowed. Software must ensure that illegal transitions between rows do not occur between blocks of a multi-block transfer. For example, if block N
is in row 10 then the only allowed rows for block N + 1 are rows 10, 5 or 1.
Note:
19.10 Programming a Channel
Three registers, the LLPx, the CTLx and CFGx, need to be programmed to set up whether single
or multi-block transfers take place, and which type of multi-block transfer is used. The different
transfer types are shown in Table 19-1 on page 324.
The “Update Method” column indicates where the values of SARx, DARx, CTLx, and LLPx are
obtained for the next block transfer when multi-block DMACA transfers are enabled.
In Table 19-1 on page 324, all other combinations of LLPx.LOC = 0, CTLx.LLP_S_EN,
CFGx.RELOAD_SR, CTLx.LLP_D_EN, and CFGx.RELOAD_DS are illegal, and causes indeterminate or erroneous behavior.
Note:
19.10.1
19.10.1.1
Programming Examples
Single-block Transfer (Row 1)
Row 5 in Table 19-1 on page 324 is also a single block transfer.
1. Read the Channel Enable register to choose a free (disabled) channel.
2. Clear any pending interrupts on the channel from the previous DMA transfer by writing
to the Interrupt Clear registers: ClearTfr, ClearBlock, ClearSrcTran, ClearDstTran,
ClearErr. Reading the Interrupt Raw Status and Interrupt Status registers confirms that
all interrupts have been cleared.
3. Program the following channel registers:
a. Write the starting source address in the SARx register for channel x.
b.
Write the starting destination address in the DARx register for channel x.
c.
Program CTLx and CFGx according to Row 1 as shown in Table 19-1 on page 324.
Program the LLPx register with ‘0’.
d. Write the control information for the DMA transfer in the CTLx register for channel
x. For example, in the register, you can program the following:
– i. Set up the transfer type (memory or non-memory peripheral for source and
destination) and flow control device by programming the TT_FC of the CTLx register.
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– ii. Set up the transfer characteristics, such as:
– Transfer width for the source in the SRC_TR_WIDTH field.
– Transfer width for the destination in the DST_TR_WIDTH field.
– Source master layer in the SMS field where source resides.
– Destination master layer in the DMS field where destination resides.
– Incrementing/decrementing or fixed address for source in SINC field.
– Incrementing/decrementing or fixed address for destination in DINC field.
e. Write the channel configuration information into the CFGx register for channel x.
– i. Designate the handshaking interface type (hardware or software) for the source
and destination peripherals. This is not required for memory. This step requires
programming the HS_SEL_SRC/HS_SEL_DST bits, respectively. Writing a ‘0’
activates the hardware handshaking interface to handle source/destination requests.
Writing a ‘1’ activates the software handshaking interface to handle
source/destination requests.
– ii. If the hardware handshaking interface is activated for the source or destination
peripheral, assign a handshaking interface to the source and destination peripheral.
This requires programming the SRC_PER and DEST_PER bits, respectively.
4. After the DMACA selected channel has been programmed, enable the channel by writing a ‘1’ to the ChEnReg.CH_EN bit. Make sure that bit 0 of the DmaCfgReg register is
enabled.
5. Source and destination request single and burst DMA transactions to transfer the block
of data (assuming non-memory peripherals). The DMACA acknowledges at the completion of every transaction (burst and single) in the block and carry out the block
transfer.
6. Once the transfer completes, hardware sets the interrupts and disables the channel. At
this time you can either respond to the Block Complete or Transfer Complete interrupts,
or poll for the Channel Enable (ChEnReg.CH_EN) bit until it is cleared by hardware, to
detect when the transfer is complete.
19.10.1.2
Multi-block Transfer with Linked List for Source and Linked List for Destination (Row 10)
1. Read the Channel Enable register to choose a free (disabled) channel.
2. Set up the chain of Linked List Items (otherwise known as block descriptors) in memory.
Write the control information in the LLI.CTLx register location of the block descriptor for
each LLI in memory (see Figure 19-7 on page 323) for channel x. For example, in the
register, you can program the following:
a. Set up the transfer type (memory or non-memory peripheral for source and destination) and flow control device by programming the TT_FC of the CTLx register.
b.
Set up the transfer characteristics, such as:
– i. Transfer width for the source in the SRC_TR_WIDTH field.
– ii. Transfer width for the destination in the DST_TR_WIDTH field.
– iii. Source master layer in the SMS field where source resides.
– iv. Destination master layer in the DMS field where destination resides.
– v. Incrementing/decrementing or fixed address for source in SINC field.
– vi. Incrementing/decrementing or fixed address for destination DINC field.
3. Write the channel configuration information into the CFGx register for channel x.
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a. Designate the handshaking interface type (hardware or software) for the source
and destination peripherals. This is not required for memory. This step requires programming the HS_SEL_SRC/HS_SEL_DST bits, respectively. Writing a ‘0’
activates the hardware handshaking interface to handle source/destination
requests for the specific channel. Writing a ‘1’ activates the software handshaking
interface to handle source/destination requests.
b.
If the hardware handshaking interface is activated for the source or destination
peripheral, assign the handshaking interface to the source and destination peripheral. This requires programming the SRC_PER and DEST_PER bits, respectively.
4. Make sure that the LLI.CTLx register locations of all LLI entries in memory (except the
last) are set as shown in Row 10 of Table 19-1 on page 324. The LLI.CTLx register of
the last Linked List Item must be set as described in Row 1 or Row 5 of Table 19-1 on
page 324. Figure 19-9 on page 330 shows a Linked List example with two list items.
5. Make sure that the LLI.LLPx register locations of all LLI entries in memory (except the
last) are non-zero and point to the base address of the next Linked List Item.
6. Make sure that the LLI.SARx/LLI.DARx register locations of all LLI entries in memory
point to the start source/destination block address preceding that LLI fetch.
7. Make sure that the LLI.CTLx.DONE field of the LLI.CTLx register locations of all LLI
entries in memory are cleared.
8. Clear any pending interrupts on the channel from the previous DMA transfer by writing
to the Interrupt Clear registers: ClearTfr, ClearBlock, ClearSrcTran, ClearDstTran,
ClearErr. Reading the Interrupt Raw Status and Interrupt Status registers confirms that
all interrupts have been cleared.
9. Program the CTLx, CFGx registers according to Row 10 as shown in Table 19-1 on
page 324.
10. Program the LLPx register with LLPx(0), the pointer to the first Linked List item.
11. Finally, enable the channel by writing a ‘1’ to the ChEnReg.CH_EN bit. The transfer is
performed.
12. The DMACA fetches the first LLI from the location pointed to by LLPx(0).
Note:
The LLI.SARx, LLI. DARx, LLI.LLPx and LLI.CTLx registers are fetched. The DMACA automatically reprograms the SARx, DARx, LLPx and CTLx channel registers from the LLPx(0).
13. Source and destination request single and burst DMA transactions to transfer the block
of data (assuming non-memory peripheral). The DMACA acknowledges at the completion of every transaction (burst and single) in the block and carry out the block transfer.
Note:
Table 19-1 on page 324
14. The DMACA does not wait for the block interrupt to be cleared, but continues fetching
the next LLI from the memory location pointed to by current LLPx register and automatically reprograms the SARx, DARx, LLPx and CTLx channel registers. The DMA
transfer continues until the DMACA determines that the CTLx and LLPx registers at the
end of a block transfer match that described in Row 1 or Row 5 of Table 19-1 on page
324. The DMACA then knows that the previous block transferred was the last block in
the DMA transfer. The DMA transfer might look like that shown in Figure 19-8 on page
329.
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Figure 19-8. Multi-Block with Linked List Address for Source and Destination
Address of
Destination Layer
Address of
Source Layer
Block 2
SAR(2)
Block 2
DAR(2)
Block 1
SAR(1)
Block 1
DAR(1)
Block 0
Block 0
DAR(0)
SAR(0)
Source Blocks
Destination Blocks
If the user needs to execute a DMA transfer where the source and destination address are contiguous but the amount of data to be transferred is greater than the maximum block size
CTLx.BLOCK_TS, then this can be achieved using the type of multi-block transfer as shown in
Figure 19-9 on page 330.
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Figure 19-9. Multi-Block with Linked Address for Source and Destination Blocks are
Contiguous
Address of
Source Layer
Address of
Destination Layer
Block 2
DAR(3)
Block 2
Block 2
SAR(3)
DAR(2)
Block 2
Block 1
SAR(2)
DAR(1)
Block 1
Block 0
SAR(1)
DAR(0)
Block 0
SAR(0)
Source Blocks
Destination Blocks
The DMA transfer flow is shown in Figure 19-11 on page 333.
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Figure 19-10. DMA Transfer Flow for Source and Destination Linked List Address
Channel enabled by
software
LLI Fetch
Hardware reprograms
SARx, DARx, CTLx, LLPx
DMAC block transfer
Source/destination
status fetch
Block Complete interrupt
generated here
Is DMAC in
Row1 of
DMAC State Machine Table?
DMAC transfer Complete
interrupt generated here
no
yes
Channel Disabled by
hardware
19.10.1.3
Multi-block Transfer with Source Address Auto-reloaded and Destination Address Auto-reloaded (Row 4)
1. Read the Channel Enable register to choose an available (disabled) channel.
2. Clear any pending interrupts on the channel from the previous DMA transfer by writing
to the Interrupt Clear registers: ClearTfr, ClearBlock, ClearSrcTran, ClearDstTran,
ClearErr. Reading the Interrupt Raw Status and Interrupt Status registers confirms that
all interrupts have been cleared.
3. Program the following channel registers:
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a. Write the starting source address in the SARx register for channel x.
b.
Write the starting destination address in the DARx register for channel x.
c.
Program CTLx and CFGx according to Row 4 as shown in Table 19-1 on page 324.
Program the LLPx register with ‘0’.
d. Write the control information for the DMA transfer in the CTLx register for channel
x. For example, in the register, you can program the following:
– i. Set up the transfer type (memory or non-memory peripheral for source and
destination) and flow control device by programming the TT_FC of the CTLx register.
– ii. Set up the transfer characteristics, such as:
– Transfer width for the source in the SRC_TR_WIDTH field.
– Transfer width for the destination in the DST_TR_WIDTH field.
– Source master layer in the SMS field where source resides.
– Destination master layer in the DMS field where destination resides.
– Incrementing/decrementing or fixed address for source in SINC field.
– Incrementing/decrementing or fixed address for destination in DINC field.
e. Write the channel configuration information into the CFGx register for channel x.
Ensure that the reload bits, CFGx. RELOAD_SR and CFGx.RELOAD_DS are
enabled.
– i. Designate the handshaking interface type (hardware or software) for the source
and destination peripherals. This is not required for memory. This step requires
programming the HS_SEL_SRC/HS_SEL_DST bits, respectively. Writing a ‘0’
activates the hardware handshaking interface to handle source/destination requests
for the specific channel. Writing a ‘1’ activates the software handshaking interface to
handle source/destination requests.
– ii. If the hardware handshaking interface is activated for the source or destination
peripheral, assign handshaking interface to the source and destination peripheral.
This requires programming the SRC_PER and DEST_PER bits, respectively.
4. After the DMACA selected channel has been programmed, enable the channel by writing a ‘1’ to the ChEnReg.CH_EN bit. Make sure that bit 0 of the DmaCfgReg register is
enabled.
5. Source and destination request single and burst DMACA transactions to transfer the
block of data (assuming non-memory peripherals). The DMACA acknowledges on completion of each burst/single transaction and carry out the block transfer.
6. When the block transfer has completed, the DMACA reloads the SARx, DARx and
CTLx registers. Hardware sets the Block Complete interrupt. The DMACA then samples the row number as shown in Table 19-1 on page 324. If the DMACA is in Row 1,
then the DMA transfer has completed. Hardware sets the transfer complete interrupt
and disables the channel. So you can either respond to the Block Complete or Transfer
Complete interrupts, or poll for the Channel Enable (ChEnReg.CH_EN) bit until it is disabled, to detect when the transfer is complete. If the DMACA is not in Row 1, the next
step is performed.
7. The DMA transfer proceeds as follows:
a. If interrupts are enabled (CTLx.INT_EN = 1) and the block complete interrupt is unmasked (MaskBlock[x] = 1’b1, where x is the channel number) hardware sets the
block complete interrupt when the block transfer has completed. It then stalls until
the block complete interrupt is cleared by software. If the next block is to be the last
block in the DMA transfer, then the block complete ISR (interrupt service routine)
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should clear the reload bits in the CFGx.RELOAD_SR and CFGx.RELOAD_DS
registers. This put the DMACA into Row 1 as shown in Table 19-1 on page 324. If
the next block is not the last block in the DMA transfer, then the reload bits should
remain enabled to keep the DMACA in Row 4.
b.
If interrupts are disabled (CTLx.INT_EN = 0) or the block complete interrupt is
masked (MaskBlock[x] = 1’b0, where x is the channel number), then hardware does
not stall until it detects a write to the block complete interrupt clear register but
starts the next block transfer immediately. In this case software must clear the
reload bits in the CFGx.RELOAD_SR and CFGx.RELOAD_DS registers to put the
DMACA into ROW 1 of Table 19-1 on page 324 before the last block of the DMA
transfer has completed. The transfer is similar to that shown in Figure 19-11 on
page 333. The DMA transfer flow is shown in Figure 19-12 on page 334.
Figure 19-11. Multi-Block DMA Transfer with Source and Destination Address Auto-reloaded
Address of
Source Layer
Address of
Destination Layer
Block0
Block1
Block2
SAR
DAR
BlockN
Source Blocks
Destination Blocks
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Figure 19-12. DMA Transfer Flow for Source and Destination Address Auto-reloaded
Channel Enabled by
software
Block Transfer
Reload SARx, DARx, CTLx
Block Complete interrupt
generated here
DMAC transfer Complete
interrupt generated here
yes
Is DMAC in Row1 of
DMAC State Machine Table?
Channel Disabled by
hardware
no
CTLx.INT_EN=1
&&
MASKBLOCK[x]=1?
no
yes
Stall until block complete
interrupt cleared by software
19.10.1.4
Multi-block Transfer with Source Address Auto-reloaded and Linked List Destination Address (Row7)
1. Read the Channel Enable register to choose a free (disabled) channel.
2. Set up the chain of linked list items (otherwise known as block descriptors) in memory.
Write the control information in the LLI.CTLx register location of the block descriptor for
each LLI in memory for channel x. For example, in the register you can program the
following:
a. Set up the transfer type (memory or non-memory peripheral for source and destination) and flow control peripheral by programming the TT_FC of the CTLx register.
b.
Set up the transfer characteristics, such as:
– i. Transfer width for the source in the SRC_TR_WIDTH field.
– ii. Transfer width for the destination in the DST_TR_WIDTH field.
– iii. Source master layer in the SMS field where source resides.
– iv. Destination master layer in the DMS field where destination resides.
– v. Incrementing/decrementing or fixed address for source in SINC field.
– vi. Incrementing/decrementing or fixed address for destination DINC field.
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3. Write the starting source address in the SARx register for channel x.
Note:
The values in the LLI.SARx register locations of each of the Linked List Items (LLIs) setup up in
memory, although fetched during a LLI fetch, are not used.
4. Write the channel configuration information into the CFGx register for channel x.
a. Designate the handshaking interface type (hardware or software) for the source
and destination peripherals. This is not required for memory. This step requires programming the HS_SEL_SRC/HS_SEL_DST bits, respectively. Writing a ‘0’
activates the hardware handshaking interface to handle source/destination
requests for the specific channel. Writing a ‘1’ activates the software handshaking
interface source/destination requests.
b.
If the hardware handshaking interface is activated for the source or destination
peripheral, assign handshaking interface to the source and destination peripheral.
This requires programming the SRC_PER and DEST_PER bits, respectively.
5. Make sure that the LLI.CTLx register locations of all LLIs in memory (except the last)
are set as shown in Row 7 of Table 19-1 on page 324 while the LLI.CTLx register of the
last Linked List item must be set as described in Row 1 or Row 5 of Table 19-1 on page
324. Figure 19-7 on page 323 shows a Linked List example with two list items.
6. Make sure that the LLI.LLPx register locations of all LLIs in memory (except the last)
are non-zero and point to the next Linked List Item.
7. Make sure that the LLI.DARx register location of all LLIs in memory point to the start
destination block address proceeding that LLI fetch.
8. Make sure that the LLI.CTLx.DONE field of the LLI.CTLx register locations of all LLIs in
memory is cleared.
9. Clear any pending interrupts on the channel from the previous DMA transfer by writing
to the Interrupt Clear registers: ClearTfr, ClearBlock, ClearSrcTran, ClearDstTran,
ClearErr. Reading the Interrupt Raw Status and Interrupt Status registers confirms that
all interrupts have been cleared.
10. Program the CTLx, CFGx registers according to Row 7 as shown in Table 19-1 on page
324.
11. Program the LLPx register with LLPx(0), the pointer to the first Linked List item.
12. Finally, enable the channel by writing a ‘1’ to the ChEnReg.CH_EN bit. The transfer is
performed. Make sure that bit 0 of the DmaCfgReg register is enabled.
13. The DMACA fetches the first LLI from the location pointed to by LLPx(0).
Note:
The LLI.SARx, LLI.DARx, LLI. LLPx and LLI.CTLx registers are fetched. The LLI.SARx register
although fetched is not used.
14. Source and destination request single and burst DMACA transactions to transfer the
block of data (assuming non-memory peripherals). DMACA acknowledges at the completion of every transaction (burst and single) in the block and carry out the block
transfer.
15. Table 19-1 on page 324The DMACA reloads the SARx register from the initial value.
Hardware sets the block complete interrupt. The DMACA samples the row number as
shown in Table 19-1 on page 324. If the DMACA is in Row 1 or 5, then the DMA transfer has completed. Hardware sets the transfer complete interrupt and disables the
channel. You can either respond to the Block Complete or Transfer Complete interrupts,
or poll for the Channel Enable (ChEnReg.CH_EN) bit until it is cleared by hardware, to
detect when the transfer is complete. If the DMACA is not in Row 1 or 5 as shown in
Table 19-1 on page 324 the following steps are performed.
16. The DMA transfer proceeds as follows:
a. If interrupts are enabled (CTLx.INT_EN = 1) and the block complete interrupt is unmasked (MaskBlock[x] = 1’b1, where x is the channel number) hardware sets the
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block complete interrupt when the block transfer has completed. It then stalls until
the block complete interrupt is cleared by software. If the next block is to be the last
block in the DMA transfer, then the block complete ISR (interrupt service routine)
should clear the CFGx.RELOAD_SR source reload bit. This puts the DMACA into
Row1 as shown in Table 19-1 on page 324. If the next block is not the last block in
the DMA transfer, then the source reload bit should remain enabled to keep the
DMACA in Row 7 as shown in Table 19-1 on page 324.
b.
If interrupts are disabled (CTLx.INT_EN = 0) or the block complete interrupt is
masked (MaskBlock[x] = 1’b0, where x is the channel number) then hardware does
not stall until it detects a write to the block complete interrupt clear register but
starts the next block transfer immediately. In this case, software must clear the
source reload bit, CFGx.RELOAD_SR, to put the device into Row 1 of Table 19-1
on page 324 before the last block of the DMA transfer has completed.
17. The DMACA fetches the next LLI from memory location pointed to by the current LLPx
register, and automatically reprograms the DARx, CTLx and LLPx channel registers.
Note that the SARx is not re-programmed as the reloaded value is used for the next
DMA block transfer. If the next block is the last block of the DMA transfer then the CTLx
and LLPx registers just fetched from the LLI should match Row 1 or Row 5 of Table 191 on page 324. The DMA transfer might look like that shown in Figure 19-13 on page
336.
Figure 19-13. Multi-Block DMA Transfer with Source Address Auto-reloaded and Linked List
Address of
Destination Layer
Address of
Source Layer
Block0
DAR(0)
Block1
DAR(1)
SAR
Block2
DAR(2)
BlockN
DAR(N)
Source Blocks
Destination Blocks
Destination Address
The DMA Transfer flow is shown in Figure 19-14 on page 337.
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Figure 19-14. DMA Transfer Flow for Source Address Auto-reloaded and Linked List Destination Address
Channel Enabled by
software
LLI Fetch
Hardware reprograms
DARx, CTLx, LLPx
DMAC block transfer
Source/destination status fetch
Reload SARx
Block Complete interrupt
generated here
DMAC Transfer Complete
interrupt generated here
yes
Channel Disabled by
hardware
Is DMAC in
Row1 or Row5 of
DMAC State Machine Table?
no
CTLx.INT_EN=1
&&
MASKBLOCK[X]=1 ?
no
yes
Stall until block interrupt
Cleared by hardware
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19.10.1.5
Multi-block Transfer with Source Address Auto-reloaded and Contiguous Destination Address (Row 3)
1. Read the Channel Enable register to choose a free (disabled) channel.
2. Clear any pending interrupts on the channel from the previous DMA transfer by writing
a ‘1’ to the Interrupt Clear registers: ClearTfr, ClearBlock, ClearSrcTran, ClearDstTran,
ClearErr. Reading the Interrupt Raw Status and Interrupt Status registers confirms that
all interrupts have been cleared.
3. Program the following channel registers:
a. Write the starting source address in the SARx register for channel x.
b.
Write the starting destination address in the DARx register for channel x.
c.
Program CTLx and CFGx according to Row 3 as shown in Table 19-1 on page 324.
Program the LLPx register with ‘0’.
d. Write the control information for the DMA transfer in the CTLx register for channel
x. For example, in this register, you can program the following:
– i. Set up the transfer type (memory or non-memory peripheral for source and
destination) and flow control device by programming the TT_FC of the CTLx register.
– ii. Set up the transfer characteristics, such as:
– Transfer width for the source in the SRC_TR_WIDTH field.
– Transfer width for the destination in the DST_TR_WIDTH field.
– Source master layer in the SMS field where source resides.
– Destination master layer in the DMS field where destination resides.
– Incrementing/decrementing or fixed address for source in SINC field.
– Incrementing/decrementing or fixed address for destination in DINC field.
e. Write the channel configuration information into the CFGx register for channel x.
– i. Designate the handshaking interface type (hardware or software) for the source
and destination peripherals. This is not required for memory. This step requires
programming the HS_SEL_SRC/HS_SEL_DST bits, respectively. Writing a ‘0’
activates the hardware handshaking interface to handle source/destination requests
for the specific channel. Writing a ‘1’ activates the software handshaking interface to
handle source/destination requests.
– ii. If the hardware handshaking interface is activated for the source or destination
peripheral, assign handshaking interface to the source and destination peripheral.
This requires programming the SRC_PER and DEST_PER bits, respectively.
4. After the DMACA channel has been programmed, enable the channel by writing a ‘1’ to
the ChEnReg.CH_EN bit. Make sure that bit 0 of the DmaCfgReg register is enabled.
5. Source and destination request single and burst DMACA transactions to transfer the
block of data (assuming non-memory peripherals). The DMACA acknowledges at the
completion of every transaction (burst and single) in the block and carries out the block
transfer.
6. When the block transfer has completed, the DMACA reloads the SARx register. The
DARx register remains unchanged. Hardware sets the block complete interrupt. The
DMACA then samples the row number as shown in Table 19-1 on page 324. If the
DMACA is in Row 1, then the DMA transfer has completed. Hardware sets the transfer
complete interrupt and disables the channel. So you can either respond to the Block
Complete or Transfer Complete interrupts, or poll for the Channel Enable (ChEn-
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Reg.CH_EN) bit until it is cleared by hardware, to detect when the transfer is complete.
If the DMACA is not in Row 1, the next step is performed.
7. The DMA transfer proceeds as follows:
a. If interrupts are enabled (CTLx.INT_EN = 1) and the block complete interrupt is unmasked (MaskBlock[x] = 1’b1, where x is the channel number) hardware sets the
block complete interrupt when the block transfer has completed. It then stalls until
the block complete interrupt is cleared by software. If the next block is to be the last
block in the DMA transfer, then the block complete ISR (interrupt service routine)
should clear the source reload bit, CFGx.RELOAD_SR. This puts the DMACA into
Row1 as shown in Table 19-1 on page 324. If the next block is not the last block in
the DMA transfer then the source reload bit should remain enabled to keep the
DMACA in Row3 as shown in Table 19-1 on page 324.
b.
If interrupts are disabled (CTLx.INT_EN = 0) or the block complete interrupt is
masked (MaskBlock[x] = 1’b0, where x is the channel number) then hardware does
not stall until it detects a write to the block complete interrupt clear register but
starts the next block transfer immediately. In this case software must clear the
source reload bit, CFGx.RELOAD_SR, to put the device into ROW 1 of Table 19-1
on page 324 before the last block of the DMA transfer has completed.
The transfer is similar to that shown in Figure 19-15 on page 339.
The DMA Transfer flow is shown in Figure 19-16 on page 340.
Figure 19-15. Multi-block Transfer with Source Address Auto-reloaded and Contiguous Destination Address
Address of
Destination Layer
Address of
Source Layer
Block2
DAR(2)
Block1
DAR(1)
Block0
SAR
DAR(0)
Source Blocks
Destination Blocks
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Figure 19-16. DMA Transfer for Source Address Auto-reloaded and Contiguous Destination
Address
Channel Enabled by
software
Block Transfer
Reload SARx, CTLx
Block Complete interrupt
generated here
DMAC Transfer Complete
interrupt generated here
yes
Channel Disabled by
hardware
Is DMAC in Row1 of
DMAC State Machine Table?
no
CTLx.INT_EN=1
&&
MASKBLOCK[x]=1?
no
yes
Stall until Block Complete
interrupt cleared by software
19.10.1.6
Multi-block DMA Transfer with Linked List for Source and Contiguous Destination Address (Row 8)
1. Read the Channel Enable register to choose a free (disabled) channel.
2. Set up the linked list in memory. Write the control information in the LLI. CTLx register
location of the block descriptor for each LLI in memory for channel x. For example, in
the register, you can program the following:
a. Set up the transfer type (memory or non-memory peripheral for source and destination) and flow control device by programming the TT_FC of the CTLx register.
b.
Set up the transfer characteristics, such as:
– i. Transfer width for the source in the SRC_TR_WIDTH field.
– ii. Transfer width for the destination in the DST_TR_WIDTH field.
– iii. Source master layer in the SMS field where source resides.
– iv. Destination master layer in the DMS field where destination resides.
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– v. Incrementing/decrementing or fixed address for source in SINC field.
– vi. Incrementing/decrementing or fixed address for destination DINC field.
3. Write the starting destination address in the DARx register for channel x.
Note:
The values in the LLI.DARx register location of each Linked List Item (LLI) in memory, although
fetched during an LLI fetch, are not used.
4. Write the channel configuration information into the CFGx register for channel x.
a. Designate the handshaking interface type (hardware or software) for the source
and destination peripherals. This is not required for memory. This step requires programming the HS_SEL_SRC/HS_SEL_DST bits, respectively. Writing a ‘0’
activates the hardware handshaking interface to handle source/destination
requests for the specific channel. Writing a ‘1’ activates the software handshaking
interface to handle source/destination requests.
b.
If the hardware handshaking interface is activated for the source or destination
peripheral, assign handshaking interface to the source and destination peripherals.
This requires programming the SRC_PER and DEST_PER bits, respectively.
5. Make sure that all LLI.CTLx register locations of the LLI (except the last) are set as
shown in Row 8 of Table 19-1 on page 324, while the LLI.CTLx register of the last
Linked List item must be set as described in Row 1 or Row 5 of Table 19-1 on page
324. Figure 19-7 on page 323 shows a Linked List example with two list items.
6. Make sure that the LLI.LLPx register locations of all LLIs in memory (except the last)
are non-zero and point to the next Linked List Item.
7. Make sure that the LLI.SARx register location of all LLIs in memory point to the start
source block address proceeding that LLI fetch.
8. Make sure that the LLI.CTLx.DONE field of the LLI.CTLx register locations of all LLIs in
memory is cleared.
9. Clear any pending interrupts on the channel from the previous DMA transfer by writing
a ‘1’ to the Interrupt Clear registers: ClearTfr, ClearBlock, ClearSrcTran, ClearDstTran,
ClearErr. Reading the Interrupt Raw Status and Interrupt Status registers confirms that
all interrupts have been cleared.
10. Program the CTLx, CFGx registers according to Row 8 as shown in Table 19-1 on page
324
11. Program the LLPx register with LLPx(0), the pointer to the first Linked List item.
12. Finally, enable the channel by writing a ‘1’ to the ChEnReg.CH_EN bit. The transfer is
performed. Make sure that bit 0 of the DmaCfgReg register is enabled.
13. The DMACA fetches the first LLI from the location pointed to by LLPx(0).
Note:
The LLI.SARx, LLI.DARx, LLI.LLPx and LLI.CTLx registers are fetched. The LLI.DARx register
location of the LLI although fetched is not used. The DARx register in the DMACA remains
unchanged.
14. Source and destination requests single and burst DMACA transactions to transfer the
block of data (assuming non-memory peripherals). The DMACA acknowledges at the
completion of every transaction (burst and single) in the block and carry out the block
transfer.
Note:
15. The DMACA does not wait for the block interrupt to be cleared, but continues and
fetches the next LLI from the memory location pointed to by current LLPx register and
automatically reprograms the SARx, CTLx and LLPx channel registers. The DARx register is left unchanged. The DMA transfer continues until the DMACA samples the CTLx
and LLPx registers at the end of a block transfer match that described in Row 1 or Row
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5 of Table 19-1 on page 324. The DMACA then knows that the previous block transferred was the last block in the DMA transfer.
The DMACA transfer might look like that shown in Figure 19-17 on page 342 Note that the destination address is decrementing.
Figure 19-17. DMA Transfer with Linked List Source Address and Contiguous Destination
Address
Address of
Destination Layer
Address of
Source Layer
Block 2
SAR(2)
Block 2
DAR(2)
Block 1
Block 1
SAR(1)
DAR(1)
Block 0
Block 0
DAR(0)
SAR(0)
Source Blocks
Destination Blocks
The DMA transfer flow is shown in Figure 19-19 on page 343.
Figure 19-18.
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Figure 19-19. DMA Transfer Flow for Source Address Auto-reloaded and Contiguous Destination Address
Channel Enabled by
software
LLI Fetch
Hardware reprograms
SARx, CTLx, LLPx
DMAC block transfer
Source/destination
status fetch
Block Complete interrupt
generated here
Is DMAC in
Row 1 of Table 4 ?
DMAC Transfer Complete
interrupt generated here
no
yes
Channel Disabled by
hardware
19.11 Disabling a Channel Prior to Transfer Completion
Under normal operation, software enables a channel by writing a ‘1’ to the Channel Enable Register, ChEnReg.CH_EN, and hardware disables a channel on transfer completion by clearing the
ChEnReg.CH_EN register bit.
The recommended way for software to disable a channel without losing data is to use the
CH_SUSP bit in conjunction with the FIFO_EMPTY bit in the Channel Configuration Register
(CFGx) register.
1. If software wishes to disable a channel prior to the DMA transfer completion, then it can
set the CFGx.CH_SUSP bit to tell the DMACA to halt all transfers from the source
peripheral. Therefore, the channel FIFO receives no new data.
2. Software can now poll the CFGx.FIFO_EMPTY bit until it indicates that the channel
FIFO is empty.
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3. The ChEnReg.CH_EN bit can then be cleared by software once the channel FIFO is
empty.
When CTLx.SRC_TR_WIDTH is less than CTLx.DST_TR_WIDTH and the CFGx.CH_SUSP bit
is high, the CFGx.FIFO_EMPTY is asserted once the contents of the FIFO do not permit a single
word of CTLx.DST_TR_WIDTH to be formed. However, there may still be data in the channel
FIFO but not enough to form a single transfer of CTLx.DST_TR_WIDTH width. In this configuration, once the channel is disabled, the remaining data in the channel FIFO are not transferred to
the destination peripheral. It is permitted to remove the channel from the suspension state by
writing a ‘0’ to the CFGx.CH_SUSP register. The DMA transfer completes in the normal manner.
Note:
19.11.1
If a channel is disabled by software, an active single or burst transaction is not guaranteed to
receive an acknowledgement.
Abnormal Transfer Termination
A DMACA DMA transfer may be terminated abruptly by software by clearing the channel enable
bit, ChEnReg.CH_EN. This does not mean that the channel is disabled immediately after the
ChEnReg.CH_EN bit is cleared over the HSB slave interface. Consider this as a request to disable the channel. The ChEnReg.CH_EN must be polled and then it must be confirmed that the
channel is disabled by reading back 0. A case where the channel is not be disabled after a channel disable request is where either the source or destination has received a split or retry
response. The DMACA must keep re-attempting the transfer to the system HADDR that originally received the split or retry response until an OKAY response is returned. To do otherwise is
an System Bus protocol violation.
Software may terminate all channels abruptly by clearing the global enable bit in the DMACA
Configuration Register (DmaCfgReg[0]). Again, this does not mean that all channels are disabled immediately after the DmaCfgReg[0] is cleared over the HSB slave interface. Consider
this as a request to disable all channels. The ChEnReg must be polled and then it must be confirmed that all channels are disabled by reading back ‘0’.
Note:
If the channel enable bit is cleared while there is data in the channel FIFO, this data is not sent to
the destination peripheral and is not present when the channel is re-enabled. For read sensitive
source peripherals such as a source FIFO this data is therefore lost. When the source is not a
read sensitive device (i.e., memory), disabling a channel without waiting for the channel FIFO to
empty may be acceptable as the data is available from the source peripheral upon request and is
not lost.
Note:
If a channel is disabled by software, an active single or burst transaction is not guaranteed to
receive an acknowledgement.
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19.12 User Interface
Table 19-2.
DMA Controller Memory Map
Offset
Register
Register Name
Access
Reset Value
0x000
Channel 0 Source Address Register
SAR0
Read/Write
0x00000000
0x008
Channel 0 Destination Address Register
DAR0
Read/Write
0x00000000
0x010
Channel 0 Linked List Pointer Register
LLP0
Read/Write
0x00000000
0x018
Channel 0 Control Register Low
CTL0L
Read/Write
0x00304801
0x01C
Channel 0 Control Register High
CTL0H
Read/Write
0x00000002
0x040
Channel 0 Configuration Register Low
CFG0L
Read/Write
0x00000c00
0x044
Channel 0 Configuration Register High
CFG0H
Read/Write
0x00000004
0x048
Channel 0 Source Gather Register
SGR0
Read/Write
0x00000000
0x050
Channel 0 Destination Scatter Register
DSR0
Read/Write
0x00000000
0x058
Channel 1 Source Address Register
SAR1
Read/Write
0x00000000
0x060
Channel 1 Destination Address Register
DAR1
Read/Write
0x00000000
0x068
Channel 1 Linked List Pointer Register
LLP1
Read/Write
0x00000000
0x070
Channel 1 Control Register Low
CTL1L
Read/Write
0x00304801
0x074
Channel 1 Control Register High
CTL1H
Read/Write
0x00000002
0x098
Channel 1 Configuration Register Low
CFG1L
Read/Write
0x00000c20
0x09C
Channel 1 Configuration Register High
CFG1H
Read/Write
0x00000004
0x0A0
Channel 1Source Gather Register
SGR1
Read/Write
0x00000000
0x0A8
Channel 1 Destination Scatter Register
DSR1
Read/Write
0x00000000
0x0B0
Channel 2 Source Address Register
SAR2
Read/Write
0x00000000
0x0B8
Channel 2 Destination Address Register
DAR2
Read/Write
0x00000000
0x0C0
Channel 2 Linked List Pointer Register
LLP2
Read/Write
0x00000000
0x0C8
Channel 2 Control Register Low
CTL2L
Read/Write
0x00304801
0x0CC
Channel 2 Control Register High
CTL2H
Read/Write
0x00000002
0x0F0
Channel 2 Configuration Register Low
CFG2L
Read/Write
0x00000c40
0x0F4
Channel 2 Configuration Register High
CFG2H
Read/Write
0x00000004
0x0F8
Channel 2 Source Gather Register
SGR2
Read/Write
0x00000000
0x100
Channel 2 Destination Scatter Register
DSR2
Read/Write
0x00000000
0x108
Channel 3 Source Address Register
SAR3
Read/Write
0x00000000
0x110
Channel 3 Destination Address Register
DAR3
Read/Write
0x00000000
0x118
Channel 3 Linked List Pointer Register
LLP3
Read/Write
0x00000000
0x120
Channel 3 Control Register Low
CTL3L
Read/Write
0x00304801
0x124
Channel 3 Control Register High
CTL3H
Read/Write
0x00000002
0x148
Channel 3 Configuration Register Low
CFG3L
Read/Write
0x00000c60
0x14c
Channel 3 Configuration Register High
CFG3H
Read/Write
0x00000004
SGR3
Read/Write
0x00000000
0x150
Channel 3 Source Gather Register
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Table 19-2.
DMA Controller Memory Map (Continued)
Offset
Register
Register Name
Access
Reset Value
0x158
Channel 3Destination Scatter Register
DSR3
Read/Write
0x00000000
0x2C0
Raw Status for IntTfr Interrupt
RawTfr
Read-only
0x00000000
0x2C8
Raw Status for IntBlock Interrupt
RawBlock
Read-only
0x00000000
0x2D0
Raw Status for IntSrcTran Interrupt
RawSrcTran
Read-only
0x00000000
0x2D8
Raw Status for IntDstTran Interrupt
RawDstTran
Read-only
0x00000000
0x2E0
Raw Status for IntErr Interrupt
RawErr
Read-only
0x00000000
0x2E8
Status for IntTfr Interrupt
StatusTfr
Read-only
0x00000000
0x2F0
Status for IntBlock Interrupt
StatusBlock
Read-only
0x00000000
0x2F8
Status for IntSrcTran Interrupt
StatusSrcTran
Read-only
0x00000000
0x300
Status for IntDstTran Interrupt
StatusDstTran
Read-only
0x00000000
0x308
Status for IntErr Interrupt
StatusErr
Read-only
0x00000000
0x310
Mask for IntTfr Interrupt
MaskTfr
Read/Write
0x00000000
0x318
Mask for IntBlock Interrupt
MaskBlock
Read/Write
0x00000000
0x320
Mask for IntSrcTran Interrupt
MaskSrcTran
Read/Write
0x00000000
0x328
Mask for IntDstTran Interrupt
MaskDstTran
Read/Write
0x00000000
0x330
Mask for IntErr Interrupt
MaskErr
Read/Write
0x00000000
0x338
Clear for IntTfr Interrupt
ClearTfr
Write-only
0x00000000
0x340
Clear for IntBlock Interrupt
ClearBlock
Write-only
0x00000000
0x348
Clear for IntSrcTran Interrupt
ClearSrcTran
Write-only
0x00000000
0x350
Clear for IntDstTran Interrupt
ClearDstTran
Write-only
0x00000000
0x358
Clear for IntErr Interrupt
ClearErr
Write-only
0x00000000
0x360
Status for each interrupt type
StatusInt
Read-only
0x00000000
0x368
Source Software Transaction Request Register
ReqSrcReg
Read/Write
0x00000000
0x370
Destination Software Transaction Request Register
ReqDstReg
Read/Write
0x00000000
0x378
Single Source Transaction Request Register
SglReqSrcReg
Read/Write
0x00000000
0x380
Single Destination Transaction Request Register
SglReqDstReg
Read/Write
0x00000000
0x388
Last Source Transaction Request Register
LstSrcReg
Read/Write
0x00000000
0x390
Last Destination Transaction Request Register
LstDstReg
Read/Write
0x00000000
0x398
DMA Configuration Register
DmaCfgReg
Read/Write
0x00000000
0x3A0
DMA Channel Enable Register
ChEnReg
Read/Write
0x00000000
0x3F8
DMA Component ID Register Low
DmaCompIdRegL
Read-only
0x44571110
0x3FC
DMA Component ID Register High
DmaCompIdRegH
Read-only
0x3230362A
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19.12.1
Name:
Channel x Source Address Register
SARx
Access Type:
Read/Write
Offset:
0x000 + [x * 0x58]
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
SADD[31:24]
23
22
21
20
SADD[23:16]
15
14
13
12
SADD[15:8]
7
6
5
4
SADD[7:0]
• SADD: Source Address of DMA transfer
The starting System Bus source address is programmed by software before the DMA channel is enabled or by a LLI update
before the start of the DMA transfer. As the DMA transfer is in progress, this register is updated to reflect the source
address of the current System Bus transfer.
Updated after each source System Bus transfer. The SINC field in the CTLx register determines whether the address increments, decrements, or is left unchanged on every source System Bus transfer throughout the block transfer.
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19.12.2
Name:
Channel x Destination Address Register
DARx
Access Type:
Read/Write
Offset:
0x008 + [x * 0x58]
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
DADD[31:24]
23
22
21
20
DADD[23:16]
15
14
13
12
DADD[15:8]
7
6
5
4
DADD[7:0]
• DADD: Destination Address of DMA transfer
The starting System Bus destination address is programmed by software before the DMA channel is enabled or by a LLI
update before the start of the DMA transfer. As the DMA transfer is in progress, this register is updated to reflect the destination address of the current System Bus transfer.
Updated after each destination System Bus transfer. The DINC field in the CTLx register determines whether the address
increments, decrements or is left unchanged on every destination System Bus transfer throughout the block transfer.
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19.12.3
Name:
Linked List Pointer Register for Channel x
LLPx
Access Type:
Read/Write
Offset:
0x010 + [x * 0x58]
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
LOC[29:22]
23
22
21
20
LOC[21:14]
15
14
13
12
LOC[13:6]
7
6
5
4
LOC[5:0]
LMS
• LOC: Address of the next LLI
Starting address in memory of next LLI if block chaining is enabled.
The user need to program this register to point to the first Linked List Item (LLI) in memory prior to enabling the channel if
block chaining is enabled.
The LLP register has two functions:
The logical result of the equation LLP.LOC != 0 is used to set up the type of DMA transfer (single or multi-block).
If LLP.LOC is set to 0x0, then transfers using linked lists are NOT enabled. This register must be programmed prior to
enabling the channel in order to set up the transfer type.
It (LLP.LOC != 0) contains the pointer to the next Linked Listed Item for block chaining using linked lists.
The LLPx register is also used to point to the address where write back of the control and source/destination status information occurs after block completion.
• LMS: List Master Select
Identifies the High speed bus interface for the device that stores the next linked list item:
Table 19-3.
List Master Select
LMS
HSB Master
0
HSB master 1
1
HSB master 2
Other
Reserved
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19.12.4
Name:
Control Register for Channel x Low
CTLxL
Access Type:
Read/Write
Offset:
0x018 + [x * 0x58]
Reset Value:
0x00304801
31
30
23
22
DMS[0]
29
21
28
27
LLP_SRC_E
N
LLP_DST_E
N
20
19
TT_FC
15
14
13
SRC_MSIZE[1:0]
7
11
5
SRC_TR_WIDTH
4
25
SMS
DMS[1]
17
16
DST_GATHE
R_EN
SRC_GATHE
R_EN
SRC_MSIZE
[2]
10
9
8
SINC
3
24
18
DEST_MSIZE
6
DINC[0]
12
26
2
DINC[1]
1
DST_TR_WIDTH
0
INT_EN
This register contains fields that control the DMA transfer. The CTLxL register is part of the block descriptor (linked list item)
when block chaining is enabled. It can be varied on a block-by-block basis within a DMA transfer when block chaining is
enabled.
• LLP_SRC_EN
Block chaining is only enabled on the source side if the LLP_SRC_EN field is high and LLPx.LOC is non-zero.
• LLP_DST_EN
Block chaining is only enabled on the destination side if the LLP_DST_EN field is high and LLPx.LOC is non-zero.
• SMS: Source Master Select
Identifies the Master Interface layer where the source device (peripheral or memory) is accessed from
Table 19-4.
Source Master Select
SMS
HSB Master
0
HSB master 1
1
HSB master 2
Other
Reserved
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• DMS: Destination Master Select
Identifies the Master Interface layer where the destination device (peripheral or memory) resides
Table 19-5.
Destination Master Select
DMS
HSB Master
0
HSB master 1
1
HSB master 2
Other
Reserved
• TT_FC: Transfer Type and Flow Control
The four following transfer types are supported:
• Memory to Memory, Memory to Peripheral, Peripheral to Memory and Peripheral to Peripheral.
The DMACA is always the Flow Controller.
TT_FC
Transfer Type
Flow Controller
000
Memory to Memory
DMACA
001
Memory to Peripheral
DMACA
010
Peripheral to Memory
DMACA
011
Peripheral to Peripheral
DMACA
Other
Reserved
Reserved
• DST_SCATTER_EN: Destination Scatter Enable
0 = Scatter disabled
1 = Scatter enabled
Scatter on the destination side is applicable only when the CTLx.DINC bit indicates an incrementing or decrementing
address control.
• SRC_GATHER_EN: Source Gather Enable
0 = Gather disabled
1 = Gather enabled
Gather on the source side is applicable only when the CTLx.SINC bit indicates an incrementing or decrementing address
control.
• SRC_MSIZE: Source Burst Transaction Length
Number of data items, each of width CTLx.SRC_TR_WIDTH, to be read from the source every time a source burst transaction request is made from either the corresponding hardware or software handshaking interface.
SRC_MSIZE
Size (items number)
0
1
1
4
2
8
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SRC_MSIZE
Size (items number)
3
16
4
32
Other
Reserved
• DST_MSIZE: Destination Burst Transaction Length
Number of data items, each of width CTLx.DST_TR_WIDTH, to be written to the destination every time a destination burst
transaction request is made from either the corresponding hardware or software handshaking interface.
DST_MSIZE
Size (items number)
0
1
1
4
2
8
3
16
4
32
Other
Reserved
• SINC: Source Address Increment
Indicates whether to increment or decrement the source address on every source System Bus transfer. If your device is
fetching data from a source peripheral FIFO with a fixed address, then set this field to “No change”
SINC
Source Address
Increment
0
Increment
1
Decrement
Other
No change
• DINC: Destination Address Increment
Indicates whether to increment or decrement the destination address on every destination System Bus transfer. If your
device is writing data to a destination peripheral FIFO with a fixed address, then set this field to “No change”
DINC
Destination Address
Increment
0
Increment
1
Decrement
Other
No change
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• SRT_TR_WIDTH: Source Transfer Width
• DSC_TR_WIDTH: Destination Transfer Width
SRC_TR_WIDTH/DST_TR_WIDTH
Size (bits)
0
8
1
16
2
32
Other
Reserved
• INT_EN: Interrupt Enable Bit
If set, then all five interrupt generating sources are enabled.
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19.12.5
Name:
Control Register for Channel x High
CTLxH
Access Type:
Read/Write
Offset:
0x01C + [x * 0x58]
Reset Value:
0x00000002
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
DONE
7
6
5
4
BLOCK_TS[11:8]
3
2
1
0
BLOCK_TS[7:0]
• DONE: Done Bit
Software can poll this bit to see when a block transfer is complete
• BLOCK_TS: Block Transfer Size
When the DMACA is flow controller, this field is written by the user before the channel is enabled to indicate the block size.
The number programmed into BLOCK_TS indicates the total number of single transactions to perform for every block
transfer, unless the transfer is already in progress, in which case the value of BLOCK_TS indicates the number of single
transactions that have been performed so far.
The width of the single transaction is determined by CTLx.SRC_TR_WIDTH.
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19.12.6
Name:
Configuration Register for Channel x Low
CFGxL
Access Type:
Read/Write
Offset:
0x040 + [x * 0x58]
• Reset Value: 0x00000C00 + [x * 0x20]
31
30
29
28
27
26
25
24
RELOAD_D
ST
RELOAD_S
RC
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
SRC_HS_P
OL
DST_HS_PO
L
-
-
15
14
13
12
11
10
9
8
HS_SEL_SR
C
HS_SEL_DS
T
FIFO_EMPT
Y
CH_SUSP
4
3
2
1
0
-
-
-
-
-
-
-
7
6
5
CH_PRIOR
• RELOAD_DST: Automatic Destination Reload
The DARx register can be automatically reloaded from its initial value at the end of every block for multi-block transfers. A
new block transfer is then initiated.
• RELOAD_SRC: Automatic Source Reload
The SARx register can be automatically reloaded from its initial value at the end of every block for multi-block transfers. A
new block transfer is then initiated.
• SRC_HS_POL: Source Handshaking Interface Polarity
0 = Active high
1 = Active low
• DST_HS_POL: Destination Handshaking Interface Polarity
0 = Active high
1 = Active low
• HS_SEL_SRC: Source Software or Hardware Handshaking Select
This register selects which of the handshaking interfaces, hardware or software, is active for source requests on this
channel.
0 = Hardware handshaking interface. Software-initiated transaction requests are ignored.
1 = Software handshaking interface. Hardware-initiated transaction requests are ignored.
If the source peripheral is memory, then this bit is ignored.
• HS_SEL_DST: Destination Software or Hardware Handshaking Select
This register selects which of the handshaking interfaces, hardware or software, is active for destination requests on this
channel.
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0 = Hardware handshaking interface. Software-initiated transaction requests are ignored.
1 = Software handshaking interface. Hardware Initiated transaction requests are ignored.
If the destination peripheral is memory, then this bit is ignored.
• FIFO_EMPTY
Indicates if there is data left in the channel's FIFO. Can be used in conjunction with CFGx.CH_SUSP to cleanly disable a
channel.
1 = Channel's FIFO empty
0 = Channel's FIFO not empty
• CH_SUSP: Channel Suspend
Suspends all DMA data transfers from the source until this bit is cleared. There is no guarantee that the current transaction
will complete. Can also be used in conjunction with CFGx.FIFO_EMPTY to cleanly disable a channel without losing any
data.
0 = Not Suspended.
1 = Suspend. Suspend DMA transfer from the source.
• CH_PRIOR: Channel priority
A priority of 7 is the highest priority, and 0 is the lowest. This field must be programmed within the following range [0, x-1].
A programmed value outside this range causes erroneous behavior.
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19.12.7
Name:
Configuration Register for Channel x High
CFGxH
Access Type:
Read/Write
Offset:
0x044 + [x * 0x58]
Reset Value:
0x00000004
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
DEST_PER
7
6
5
SRC_PER[0]
-
-
SRC_PER[3:1]
4
3
PROTCTL
2
1
0
FIFO_MODE
FCMODE
• DEST_PER: Destination Hardware Handshaking Interface
Assigns a hardware handshaking interface (0 - DMAH_NUM_HS_INT-1) to the destination of channel x if the
CFGx.HS_SEL_DST field is 0. Otherwise, this field is ignored. The channel can then communicate with the destination
peripheral connected to that interface via the assigned hardware handshaking interface.
For correct DMA operation, only one peripheral (source or destination) should be assigned to the same handshaking
interface.
• SRC_PER: Source Hardware Handshaking Interface
Assigns a hardware handshaking interface (0 - DMAH_NUM_HS_INT-1) to the source of channel x if the
CFGx.HS_SEL_SRC field is 0. Otherwise, this field is ignored. The channel can then communicate with the source peripheral connected to that interface via the assigned hardware handshaking interface.
For correct DMACA operation, only one peripheral (source or destination) should be assigned to the same handshaking
interface.
• PROTCTL: Protection Control
Bits used to drive the System Bus HPROT[3:1] bus. The System Bus Specification recommends that the default value of
HPROT indicates a non-cached, nonbuffered, privileged data access. The reset value is used to indicate such an access.
HPROT[0] is tied high as all transfers are data accesses as there are no opcode fetches. There is a one-to-one mapping of
these register bits to the HPROT[3:1] master interface signals.
• FIFO_MODE: R/W 0x0 FIFO Mode Select
Determines how much space or data needs to be available in the FIFO before a burst transaction request is serviced.
0 = Space/data available for single System Bus transfer of the specified transfer width.
1 = Space/data available is greater than or equal to half the FIFO depth for destination transfers and less than half the FIFO
depth for source transfers. The exceptions are at the end of a burst transaction request or at the end of a block transfer.
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• FCMODE: Flow Control Mode
Determines when source transaction requests are serviced when the Destination Peripheral is the flow controller.
0 = Source transaction requests are serviced when they occur. Data pre-fetching is enabled.
1 = Source transaction requests are not serviced until a destination transaction request occurs. In this mode the amount of data
transferred from the source is limited such that it is guaranteed to be transferred to the destination prior to block termination by
the destination. Data pre-fetching is disabled.
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19.12.8
Name:
Source Gather Register for Channel x
SGRx
Access Type:
Read/Write
Offset:
0x048 + [x * 0x58]
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
SGC[11:4]
23
22
21
20
SGC[3:0]
15
14
SGI[19:16]
13
12
11
10
9
8
3
2
1
0
SGI[15:8]
7
6
5
4
SGI[7:0]
• SGC: Source Gather Count
Specifies the number of contiguous source transfers of CTLx.SRC_TR_WIDTH between successive gather intervals. This
is defined as a gather boundary.
• SGI: Source Gather Interval
Specifies the source address increment/decrement in multiples of CTLx.SRC_TR_WIDTH on a gather boundary when
gather mode is enabled for the source transfer.
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19.12.9
Name:
Destination Scatter Register for Channel x
DSRx
Access Type:
Read/Write
Offset:
0x050 + [x * 0x58]
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
DSC[11:4]
23
22
21
20
DSC[3:0]
15
14
DSI[19:16]
13
12
11
10
9
8
3
2
1
0
DSI[15:8]
7
6
5
4
DSI[7:0]
• DSC: Destination Scatter Count
Specifies the number of contiguous destination transfers of CTLx.DST_TR_WIDTH between successive scatter
boundaries.
• DSI: Destination Scatter Interval
Specifies the destination address increment/decrement in multiples of CTLx.DST_TR_WIDTH on a scatter boundary when
scatter mode is enabled for the destination transfer.
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19.12.10 Interrupt Registers
The following sections describe the registers pertaining to interrupts, their status, and how to clear them. For each channel,
there are five types of interrupt sources:
• IntTfr: DMA Transfer Complete Interrupt
This interrupt is generated on DMA transfer completion to the destination peripheral.
• IntBlock: Block Transfer Complete Interrupt
This interrupt is generated on DMA block transfer completion to the destination peripheral.
• IntSrcTran: Source Transaction Complete Interrupt
This interrupt is generated after completion of the last System Bus transfer of the requested single/burst transaction from
the handshaking interface on the source side.
If the source for a channel is memory, then that channel never generates a IntSrcTran interrupt and hence the corresponding bit in this field is not set.
• IntDstTran: Destination Transaction Complete Interrupt
This interrupt is generated after completion of the last System Bus transfer of the requested single/burst transaction from
the handshaking interface on the destination side.
If the destination for a channel is memory, then that channel never generates the IntDstTran interrupt and hence the corresponding bit in this field is not set.
• IntErr: Error Interrupt
This interrupt is generated when an ERROR response is received from an HSB slave on the HRESP bus during a DMA
transfer. In addition, the DMA transfer is cancelled and the channel is disabled.
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19.12.11 Interrupt Raw Status Registers
Name:
RawTfr, RawBlock, RawSrcTran, RawDstTran, RawErr
Access Type:
Read-only
Offset:
0x2C0, 0x2C8, 0x2D0, 0x2D8, 0x2E0
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
RAW3
RAW2
RAW1
RAW0
• RAW[3:0]Raw interrupt for each channel
Interrupt events are stored in these Raw Interrupt Status Registers before masking: RawTfr, RawBlock, RawSrcTran,
RawDstTran, RawErr. Each Raw Interrupt Status register has a bit allocated per channel, for example, RawTfr[2] is Channel 2’s raw transfer complete interrupt. Each bit in these registers is cleared by writing a 1 to the corresponding location in
the ClearTfr, ClearBlock, ClearSrcTran, ClearDstTran, ClearErr registers.
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19.12.12 Interrupt Status Registers
Name:
StatusTfr, StatusBlock, StatusSrcTran, StatusDstTran, StatusErr
Access Type:
Read-only
Offset:
0x2E8, 0x2F0, 0x2F8, 0x300, 0x308
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
STATUS3
STATUS2
STATUS1
STATUS0
• STATUS[3:0]
All interrupt events from all channels are stored in these Interrupt Status Registers after masking: StatusTfr, StatusBlock,
StatusSrcTran, StatusDstTran, StatusErr. Each Interrupt Status register has a bit allocated per channel, for example, StatusTfr[2] is Channel 2’s status transfer complete interrupt.The contents of these registers are used to generate the interrupt
signals leaving the DMACA.
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19.12.13 Interrupt Mask Registers
Name:
MaskTfr, MaskBlock, MaskSrcTran, MaskDstTran, MaskErr
Access Type:
Read/Write
Offset:
0x310, 0x318, 0x320, 0x328, 0x330
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
INT_M_WE3
INT_M_WE2
INT_M_WE1
INT_M_WE0
7
6
5
4
3
2
1
0
-
-
-
-
INT_MASK3
INT_MASK2
INT_MASK1
INT_MASK0
The contents of the Raw Status Registers are masked with the contents of the Mask Registers: MaskTfr, MaskBlock, MaskSrcTran, MaskDstTran, MaskErr. Each Interrupt Mask register has a bit allocated per channel, for example, MaskTfr[2] is
the mask bit for Channel 2’s transfer complete interrupt.
A channel’s INT_MASK bit is only written if the corresponding mask write enable bit in the INT_MASK_WE field is asserted
on the same System Bus write transfer. This allows software to set a mask bit without performing a read-modified write
operation.
For example, writing hex 01x1 to the MaskTfr register writes a 1 into MaskTfr[0], while MaskTfr[7:1] remains unchanged.
Writing hex 00xx leaves MaskTfr[7:0] unchanged.
Writing a 1 to any bit in these registers unmasks the corresponding interrupt, thus allowing the DMACA to set the appropriate bit in the Status Registers.
• INT_M_WE[11:8]: Interrupt Mask Write Enable
0 = Write disabled
1 = Write enabled
• INT_MASK[3:0]: Interrupt Mask
0= Masked
1 = Unmasked
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19.12.14 Interrupt Clear Registers
Name:
ClearTfr, ClearBlock, ClearSrcTran, ClearDstTran, ClearErr
Access Type:
Write-only
Offset:
0x338, 0x340, 0x348, 0x350, 0x358
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
CLEAR3
CLEAR2
CLEAR1
CLEAR0
• CLEAR[3:0]: Interrupt Clear
0 = No effect
1 = Clear interrupt
Each bit in the Raw Status and Status registers is cleared on the same cycle by writing a 1 to the corresponding location in
the Clear registers: ClearTfr, ClearBlock, ClearSrcTran, ClearDstTran, ClearErr. Each Interrupt Clear register has a bit allocated per channel, for example, ClearTfr[2] is the clear bit for Channel 2’s transfer complete interrupt. Writing a 0 has no
effect. These registers are not readable.
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19.12.15 Combined Interrupt Status Registers
Name:
StatusInt
Access Type:
Read-only
Offset:
0x360
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
ERR
DSTT
SRCT
BLOCK
TFR
The contents of each of the five Status Registers (StatusTfr, StatusBlock, StatusSrcTran, StatusDstTran, StatusErr) is
OR’ed to produce a single bit per interrupt type in the Combined Status Register (StatusInt).
• ERR
OR of the contents of StatusErr Register.
• DSTT
OR of the contents of StatusDstTran Register.
• SRCT
OR of the contents of StatusSrcTran Register.
• BLOCK
OR of the contents of StatusBlock Register.
• TFR
OR of the contents of StatusTfr Register.
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19.12.16 Source Software Transaction Request Register
Name:
ReqSrcReg
Access Type:
Read/write
Offset:
0x368
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
REQ_WE3
REQ_WE2
REQ_WE1
REQ_WE0
7
6
5
4
3
2
1
0
-
-
-
-
SRC_REQ3
SRC_REQ2
SRC_REQ1
SRC_REQ0
A bit is assigned for each channel in this register. ReqSrcReg[n] is ignored when software handshaking is not enabled for
the source of channel n.
A channel SRC_REQ bit is written only if the corresponding channel write enable bit in the REQ_WE field is asserted on
the same System Bus write transfer.
For example, writing 0x101 writes a 1 into ReqSrcReg[0], while ReqSrcReg[4:1] remains unchanged. Writing hex 0x0yy
leaves ReqSrcReg[4:0] unchanged. This allows software to set a bit in the ReqSrcReg register without performing a readmodified write
• REQ_WE[11:8]: Request write enable
0 = Write disabled
1 = Write enabled
• SRC_REQ[3:0]: Source request
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19.12.17 Destination Software Transaction Request Register
Name:
ReqDstReg
Access Type:
Read/write
Offset:
0x370
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
REQ_WE3
REQ_WE2
REQ_WE1
REQ_WE0
7
6
5
4
3
2
1
0
-
-
-
-
DST_REQ3
DST_REQ2
DST_REQ1
DST_REQ0
A bit is assigned for each channel in this register. ReqDstReg[n] is ignored when software handshaking is not enabled for
the source of channel n.
A channel DST_REQ bit is written only if the corresponding channel write enable bit in the REQ_WE field is asserted on the
same System Bus write transfer.
• REQ_WE[11:8]: Request write enable
0 = Write disabled
1 = Write enabled
• DST_REQ[3:0]: Destination request
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19.12.18 Single Source Transaction Request Register
Name:
SglReqSrcReg
Access Type:
Read/write
Offset:
0x378
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
REQ_WE3
REQ_WE2
REQ_WE1
REQ_WE0
7
6
5
4
3
2
1
0
-
-
-
-
S_SG_REQ3
S_SG_REQ2
S_SG_REQ1
S_SG_REQ0
A bit is assigned for each channel in this register. SglReqSrcReg[n] is ignored when software handshaking is not enabled
for the source of channel n.
A channel S_SG_REQ bit is written only if the corresponding channel write enable bit in the REQ_WE field is asserted on
the same System Bus write transfer.
• REQ_WE[11:8]: Request write enable
0 = Write disabled
1 = Write enabled
• S_SG_REQ[3:0]: Source single request
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19.12.19 Single Destination Transaction Request Register
Name:
SglReqDstReg
Access Type:
Read/write
Offset:
0x380
Reset Value:
0x0000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
REQ_WE3
REQ_WE2
REQ_WE1
REQ_WE0
7
6
5
4
3
2
1
0
-
-
-
-
D_SG_REQ3
D_SG_REQ2
D_SG_REQ1
D_SG_REQ0
A bit is assigned for each channel in this register. SglReqDstReg[n] is ignored when software handshaking is not enabled
for the source of channel n.
A channel D_SG_REQ bit is written only if the corresponding channel write enable bit in the REQ_WE field is asserted on
the same System Bus write transfer.
• REQ_WE[11:8]: Request write enable
0 = Write disabled
1 = Write enabled
• D_SG_REQ[3:0]: Destination single request
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19.12.20 Last Source Transaction Request Register
Name:
LstSrcReg
Access Type:
Read/write
Offset:
0x388
Reset Value:
0x0000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
LSTSRC_W
E3
LSTSRC_W
E2
LSTSRC_W
E1
LSTSRC_W
E0
7
6
5
4
3
2
1
0
-
-
-
-
LSTSRC3
LSTSRC2
LSTSRC1
LSTSRC0
A bit is assigned for each channel in this register. LstSrcReg[n] is ignored when software handshaking is not enabled for
the source of channel n.
A channel LSTSRC bit is written only if the corresponding channel write enable bit in the LSTSRC_WE field is asserted on
the same System Bus write transfer.
• LSTSRC_WE[11:8]: Source Last Transaction request write enable
0 = Write disabled
1 = Write enabled
• LSTSRC[3:0]: Source Last Transaction request
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19.12.21 Last Destination Transaction Request Register
Name:
LstDstReg
Access Type:
Read/write
Offset:
0x390
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
LSTDST_WE
3
LSTDST_WE
2
LSTDST_WE
1
LSTDST_WE
0
7
6
5
4
3
2
1
0
-
-
-
-
LSTDST3
LSTDST2
LSTDST1
LSTDST0
A bit is assigned for each channel in this register. LstDstReg[n] is ignored when software handshaking is not enabled for
the source of channel n.
A channel LSTDST bit is written only if the corresponding channel write enable bit in the LSTDST_WE field is asserted on
the same System Bus write transfer.
• LSTDST_WE[11:8]: Destination Last Transaction request write enable
0 = Write disabled
1 = Write enabled
• LSTDST[3:0]: Destination Last Transaction request
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19.12.22 DMA Configuration Register
Name:
DmaCfgReg
Access Type:
Read/Write
Offset:
0x398
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
DMA_EN
• DMA_EN: DMA Controller Enable
0 = DMACA Disabled
1 = DMACA Enabled.
This register is used to enable the DMACA, which must be done before any channel activity can begin.
If the global channel enable bit is cleared while any channel is still active, then DmaCfgReg.DMA_EN still returns ‘1’ to indicate that there are channels still active until hardware has terminated all activity on all channels, at which point the
DmaCfgReg.DMA_EN bit returns ‘0’.
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19.12.23 DMA Channel Enable Register
Name:
ChEnReg
Access Type:
Read/Write
Offset:
0x3A0
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
CH_EN_WE
3
CH_EN_WE
2
CH_EN_WE
1
CH_EN_WE
0
7
6
5
4
3
2
1
0
-
-
-
-
CH_EN3
CH_EN2
CH_EN1
CH_EN0
• CH_EN_WE[11:8]: Channel Enable Write Enable
The channel enable bit, CH_EN, is only written if the corresponding channel write enable bit, CH_EN_WE, is asserted on
the same System Bus write transfer.
For example, writing 0x101 writes a 1 into ChEnReg[0], while ChEnReg[7:1] remains unchanged.
• CH_EN[3:0]
0 = Disable the Channel
1 = Enable the Channel
Enables/Disables the channel. Setting this bit enables a channel, clearing this bit disables the channel.
The ChEnReg.CH_EN bit is automatically cleared by hardware to disable the channel after the last System Bus transfer of
the DMA transfer to the destination has completed.Software can therefore poll this bit to determine when a DMA transfer
has completed.
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19.12.24 DMACA Component Id Register Low
Name:
DmaCompIdRegL
Access Type:
Read-only
Offset:
0x3F8
Reset Value:
0x44571110
31
30
29
28
27
26
25
24
18
17
16
10
9
8
2
1
0
DMA_COMP_TYPE[31:24]
23
22
21
20
19
DMA_COMP_TYPE[23:16]
15
14
13
12
11
DMA_COMP_TYPE[15:8]
7
6
5
4
3
DMA_COMP_TYPE[7:0]
• DMA_COMP_TYPE
DesignWare component type number = 0x44571110.
This assigned unique hex value is constant and is derived from the two ASCII letters “DW” followed by a 32-bit unsigned
number
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19.12.25 DMACA Component Id Register High
Name:
DmaCompIdRegH
Access Type:
Read-only
Offset:
0x3FC
Reset Value:
0x3230362A
31
30
29
28
27
26
25
24
18
17
16
10
9
8
2
1
0
DMA_COMP_VERSION[31:24]
23
22
21
20
19
DMA_COMP_VERSION[23:16]
15
14
13
12
11
DMA_COMP_VERSION[15:8]
7
6
5
4
3
DMA_COMP_VERSION[7:0]
• DMA_COMP_VERSION: Version of the component
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19.13 Module Configuration
The following table defines the valid settings for the DEST_PER and SRC_PER fields in the
CFGxH register.
Table 19-6.
DMACA Handshake Interfaces
PER Value
Hardware Handshaking Interface
0
AES - RX
1
AES - TX
2
MCI - RX
3
MCI -TX
4
MSI - RX
5
MSI - TX
6
EXTRQ0
7
EXTRQ1
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20. General-Purpose Input/Output Controller (GPIO)
Rev: 1.1.0.4
20.1
Features
•
•
•
•
•
20.2
Each I/O line of the GPIO features:
Configurable pin-change, rising-edge or falling-edge interrupt on any I/O line
A glitch filter providing rejection of pulses shorter than one clock cycle
Input visibility and output control
Multiplexing of up to four peripheral functions per I/O line
Programmable internal pull-up resistor
Overview
The General Purpose Input/Output Controller manages the I/O pins of the microcontroller. Each
I/O line may be dedicated as a general-purpose I/O or be assigned to a function of an embedded
peripheral. This assures effective optimization of the pins of a product.
20.3
Block Diagram
Figure 20-1. GPIO Block Diagram
PB Configuration
Interface
Interrupt Controller
GPIO Interrupt Request
PIN
General Purpose
Input/Output - GPIO
Power Manager
CLK_GPIO
PIN
PIN
MCU
I/O Pins
PIN
PIN
Embedded
Peripheral
20.4
Pin Control
Signals
Product Dependencies
In order to use this module, other parts of the system must be configured correctly, as described
below.
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20.4.1
Module Configuration
Most of the features of the GPIO are configurable for each product. The user must refer to the
Package and Pinout chapter for these settings.
Product specific settings includes:
• Number of I/O pins.
• Functions implemented on each pin
• Peripheral function(s) multiplexed on each I/O pin
• Reset value of registers
20.4.2
Clocks
The clock for the GPIO bus interface (CLK_GPIO) is generated by the Power Manager. This
clock is enabled at reset, and can be disabled in the Power Manager.
The CLK_GPIO must be enabled in order to access the configuration registers of the GPIO or to
use the GPIO interrupts. After configuring the GPIO, the CLK_GPIO can be disabled if interrupts
are not used.
20.4.3
Interrupts
The GPIO interrupt lines are connected to the interrupt controller. Using the GPIO interrupt
requires the interrupt controller to be configured first.
20.5
Functional Description
The GPIO controls the I/O lines of the microcontroller. The control logic associated with each pin
is represented in the figure below:
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Figure 20-2. Overview of the GPIO Pad Connections
ODER
PUER
1
Periph. A output enable
Periph. B output enable
0
Periph. C output enable
Periph. D output enable
PMR1
GPER
PMR0
Periph. A output data
Periph. B output data
0
Periph. C output data
Periph. D output data
PAD
1
OVR
Periph. A input data
Periph. B input data
Periph. C input data
PVR
Periph. D input data
IER
0
Edge Detector
Glitch Filter
IMR1
GFER
20.5.1
1
1
0
Interrupt Request
IMR0
Basic Operation
20.5.1.1
I/O Line or peripheral function selection
When a pin is multiplexed with one or more peripheral functions, the selection is controlled with
the GPIO Enable Register (GPER). If a bit in GPER is written to one, the corresponding pin is
controlled by the GPIO. If a bit is written to zero, the corresponding pin is controlled by a peripheral function.
20.5.1.2
Peripheral selection
The GPIO provides multiplexing of up to four peripheral functions on a single pin. The selection
is performed by accessing Peripheral Mux Register 0 (PMR0) and Peripheral Mux Register 1
(PMR1).
20.5.1.3
Output control
When the I/O line is assigned to a peripheral function, i.e. the corresponding bit in GPER is written to zero, the drive of the I/O line is controlled by the peripheral. The peripheral, depending on
the value in PMR0 and PMR1, determines whether the pin is driven or not.
When the I/O line is controlled by the GPIO, the value of the Output Driver Enable Register
(ODER) determines if the pin is driven or not. When a bit in this register is written to one, the cor-
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responding I/O line is driven by the GPIO. When the bit is written to zero, the GPIO does not
drive the line.
The level driven on an I/O line can be determined by writing to the Output Value Register (OVR).
20.5.1.4
Inputs
The level on each I/O line can be read through the Pin Value Register (PVR). This register indicates the level of the I/O lines regardless of whether the lines are driven by the GPIO or by an
external component. Note that due to power saving measures, the PVR register can only be
read when GPER is written to one for the corresponding pin or if interrupt is enabled for the pin.
20.5.1.5
Output line timings
The figure below shows the timing of the I/O line when writing a one and a zero to OVR. The
same timing applies when performing a ‘set’ or ‘clear’ access, i.e., writing a one to the Output
Value Set Register (OVRS) or the Output Value Clear Register (OVRC). The timing of PVR is
also shown.
Figure 20-3. Output Line Timings
CLK_GPIO
Write OVR to 1
Write OVR to 0
PB Access
PB Access
OVR / I/O Line
PVR
20.5.2
Advanced Operation
20.5.2.1
Pull-up resistor control
Each I/O line is designed with an embedded pull-up resistor. The pull-up resistor can be enabled
or disabled by writing a one or a zero to the corresponding bit in the Pull-up Enable Register
(PUER). Control of the pull-up resistor is possible whether an I/O line is controlled by a peripheral or the GPIO.
20.5.2.2
Input glitch filter
Optional input glitch filters can be enabled on each I/O line. When the glitch filter is enabled, a
glitch with duration of less than 1 clock cycle is automatically rejected, while a pulse with duration of 2 clock cycles or more is accepted. For pulse durations between 1 clock cycle and 2 clock
cycles, the pulse may or may not be taken into account, depending on the precise timing of its
occurrence. Thus for a pulse to be guaranteed visible it must exceed 2 clock cycles, whereas for
a glitch to be reliably filtered out, its duration must not exceed 1 clock cycle. The filter introduces
2 clock cycles of latency.
The glitch filters are controlled by the Glitch Filter Enable Register (GFER). When a bit is written
to one in GFER, the glitch filter on the corresponding pin is enabled. The glitch filter affects only
interrupt inputs. Inputs to peripherals or the value read through PVR are not affected by the
glitch filters.
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20.5.3
Interrupts
The GPIO can be configured to generate an interrupt when it detects an input change on an I/O
line. The module can be configured to signal an interrupt whenever a pin changes value or only
to trigger on rising edges or falling edges. Interrupts are enabled on a pin by writing a one to the
corresponding bit in the Interrupt Enable Register (IER). The interrupt mode is set by writing to
the Interrupt Mode Register 0 (IMR0) and the Interrupt Mode Register 1(IMR1). Interrupts can be
enabled on a pin, regardless of the configuration of the I/O line, i.e. whether it is controlled by the
GPIO or assigned to a peripheral function.
In every port there are four interrupt lines connected to the interrupt controller. Groups of eight
interrupts in the port are ORed together to form an interrupt line.
When an interrupt event is detected on an I/O line, and the corresponding bit in IER is written to
one, the GPIO interrupt request line is asserted. A number of interrupt signals are ORed-wired
together to generate a single interrupt signal to the interrupt controller.
The Interrupt Flag Register (IFR) can by read to determine which pin(s) caused the interrupt.
The interrupt bit must be cleared by writing a one to the Interrupt Flag Clear Register (IFRC).
GPIO interrupts can only be triggered when the CLK_GPIO is enabled.
20.5.4
Interrupt Timings
The figure below shows the timing for rising edge (or pin-change) interrupts when the glitch filter
is disabled. For the pulse to be registered, it must be sampled at the rising edge of the clock. In
this example, this is not the case for the first pulse. The second pulse is however sampled on a
rising edge and will trigger an interrupt request.
Figure 20-4. Interrupt Timing With Glitch Filter Disabled
clock
Pin Level
GPIO_IFR
The figure below shows the timing for rising edge (or pin-change) interrupts when the glitch filter
is enabled. For the pulse to be registered, it must be sampled on two subsequent rising edges.
In the example, the first pulse is rejected while the second pulse is accepted and causes an
interrupt request.
Figure 20-5. Interrupt Timing With Glitch Filter Enabled
clock
Pin Level
GPIO_IFR
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20.6
User Interface
The GPIO controls all the I/O pins on the AVR32 microcontroller. The pins are managed as 32bit ports that are configurable through a PB interface. Each port has a set of configuration registers. The overall memory map of the GPIO is shown below. The number of pins and hence the
number of ports are product specific.
Figure 20-6. Overall Mermory Map
0x0000
Port 0 Configuration Registers
0x0100
Port 1 Configuration Registers
0x0200
Port 2 Configuration Registers
0x0300
Port 3 Configuration Registers
0x0400
Port 4 Configuration Registers
In the GPIO Controller Function Multiplexingtable in the Package and Pinout chapter, each
GPIO line has a unique number. Note that the PA, PB, PC and PX ports do not directly correspond to the GPIO ports. To find the corresponding port and pin the following formula can be
used:
GPIO port = floor((GPIO number) / 32), example: floor((36)/32) = 1
GPIO pin = GPIO number mod 32, example: 36 mod 32 = 4
The table below shows the configuration registers for one port. Addresses shown are relative to
the port address offset. The specific address of a configuration register is found by adding the
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register offset and the port offset to the GPIO start address. One bit in each of the configuration
registers corresponds to an I/O pin.
Table 20-1.
GPIO Register Memory Map
Offset
Register
Function
Name
Access
Reset value
0x00
GPIO Enable Register
Read/Write
GPER
Read/Write
(1)
0x04
GPIO Enable Register
Set
GPERS
Write-Only
0x08
GPIO Enable Register
Clear
GPERC
Write-Only
0x0C
GPIO Enable Register
Toggle
GPERT
Write-Only
0x10
Peripheral Mux Register 0
Read/Write
PMR0
Read/Write
0x14
Peripheral Mux Register 0
Set
PMR0S
Write-Only
0x18
Peripheral Mux Register 0
Clear
PMR0C
Write-Only
0x1C
Peripheral Mux Register 0
Toggle
PMR0T
Write-Only
0x20
Peripheral Mux Register 1
Read/Write
PMR1
Read/Write
0x24
Peripheral Mux Register 1
Set
PMR1S
Write-Only
0x28
Peripheral Mux Register 1
Clear
PMR1C
Write-Only
0x2C
Peripheral Mux Register 1
Toggle
PMR1T
Write-Only
0x40
Output Driver Enable Register
Read/Write
ODER
Read/Write
0x44
Output Driver Enable Register
Set
ODERS
Write-Only
0x48
Output Driver Enable Register
Clear
ODERC
Write-Only
0x4C
Output Driver Enable Register
Toggle
ODERT
Write-Only
0x50
Output Value Register
Read/Write
OVR
Read/Write
0x54
Output Value Register
Set
OVRS
Write-Only
0x58
Output Value Register
Clear
OVRC
Write-Only
0x5c
Output Value Register
Toggle
OVRT
Write-Only
0x60
Pin Value Register
Read
PVR
Read-Only
(2)
0x70
Pull-up Enable Register
Read/Write
PUER
Read/Write
(1)
0x74
Pull-up Enable Register
Set
PUERS
Write-Only
0x78
Pull-up Enable Register
Clear
PUERC
Write-Only
0x7C
Pull-up Enable Register
Toggle
PUERT
Write-Only
0x90
Interrupt Enable Register
Read/Write
IER
Read/Write
0x94
Interrupt Enable Register
Set
IERS
Write-Only
0x98
Interrupt Enable Register
Clear
IERC
Write-Only
0x9C
Interrupt Enable Register
Toggle
IERT
Write-Only
0xA0
Interrupt Mode Register 0
Read/Write
IMR0
Read/Write
0xA4
Interrupt Mode Register 0
Set
IMR0S
Write-Only
0xA8
Interrupt Mode Register 0
Clear
IMR0C
Write-Only
0xAC
Interrupt Mode Register 0
Toggle
IMR0T
Write-Only
0xB0
Interrupt Mode Register 1
Read/Write
IMR1
Read/Write
(1)
(1)
(1)
(1)
(1)
(1)
(1)
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Table 20-1.
GPIO Register Memory Map
Offset
Register
Function
Name
Access
0xB4
Interrupt Mode Register 1
Set
IMR1S
Write-Only
0xB8
Interrupt Mode Register 1
Clear
IMR1C
Write-Only
0xBC
Interrupt Mode Register 1
Toggle
IMR1T
Write-Only
0xC0
Glitch Filter Enable Register
Read/Write
GFER
Read/Write
0xC4
Glitch Filter Enable Register
Set
GFERS
Write-Only
0xC8
Glitch Filter Enable Register
Clear
GFERC
Write-Only
0xCC
Glitch Filter Enable Register
Toggle
GFERT
Write-Only
0xD0
Interrupt Flag Register
Read
IFR
Read-Only
0xD4
Interrupt Flag Register
-
-
-
0xD8
Interrupt Flag Register
Clear
IFRC
Write-Only
0xDC
Interrupt Flag Register
-
-
-
Reset value
(1)
(1)
1)
The reset value for these registers are device specific. Please refer to the Module Configuration section at the end of this chapter.
2)
The reset value is undefined depending on the pin states.
20.6.1
Access Types
Each configuration register can be accessed in four different ways. The first address location
can be used to write the register directly. This address can also be used to read the register
value. The following addresses facilitate three different types of write access to the register. Performing a “set” access, all bits written to one will be set. Bits written to zero will be unchanged by
the operation. Performing a “clear” access, all bits written to one will be cleared. Bits written to
zero will be unchanged by the operation. Finally, a toggle access will toggle the value of all bits
written to one. Again all bits written to zero remain unchanged. Note that for some registers (e.g.
IFR), not all access methods are permitted.
Note that for ports with less than 32 bits, the corresponding control registers will have unused
bits. This is also the case for features that are not implemented for a specific pin. Writing to an
unused bit will have no effect. Reading unused bits will always return 0.
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20.6.2
Name:
Enable Register
GPER
Access Type:
Read, Write, Set, Clear, Toggle
Offset:
0x00, 0x04, 0x08, 0x0C
Reset Value:
-
31
30
29
28
27
26
P31
P30
P29
P28
P27
P26
25
24
P25
P24
23
22
21
20
19
18
17
16
P23
P22
P21
P20
P19
P18
P17
P16
15
14
13
12
11
10
9
8
P15
P14
P13
P12
P11
P10
P9
P8
7
6
5
4
3
2
1
0
P7
P6
P5
P4
P3
P2
P1
P0
• P0-P31: Pin Enable
0: A peripheral function controls the corresponding pin.
1: The GPIO controls the corresponding pin.
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20.6.3
Name:
Peripheral Mux Register 0
PMR0
Access Type:
Read, Write, Set, Clear, Toggle
Offset:
0x10, 0x14, 0x18, 0x1C
Reset Value:
-
31
30
29
28
27
26
P31
P30
P29
P28
P27
P26
25
24
P25
P24
23
22
21
20
19
18
17
16
P23
P22
P21
P20
P19
P18
P17
P16
15
14
13
12
11
10
9
8
P15
P14
P13
P12
P11
P10
P9
P8
7
6
5
4
3
2
1
0
P7
P6
P5
P4
P3
P2
P1
P0
• P0-31: Peripheral Multiplexer Select bit 0
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20.6.4
Name:
Peripheral Mux Register 1
PMR1
Access Type:
Read, Write, Set, Clear, Toggle
Offset:
0x20, 0x24, 0x28, 0x2C
Reset Value:
-
31
30
29
28
27
26
P31
P30
P29
P28
P27
P26
25
24
P25
P24
23
22
21
20
19
18
17
16
P23
P22
P21
P20
P19
P18
P17
P16
15
14
13
12
11
10
9
8
P15
P14
P13
P12
P11
P10
P9
P8
7
6
5
4
3
2
1
0
P7
P6
P5
P4
P3
P2
P1
P0
• P0-31: Peripheral Multiplexer Select bit 1
{PMR1, PMR0}
00
01
10
11
Selected Peripheral Function
A
B
C
D
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20.6.5
Name:
Output Driver Enable Register
ODER
Access Type:
Read, Write, Set, Clear, Toggle
Offset:
0x40, 0x44, 0x48, 0x4C
Reset Value:
-
31
30
29
28
27
26
P31
P30
P29
P28
P27
P26
25
24
P25
P24
23
22
21
20
19
18
17
16
P23
P22
P21
P20
P19
P18
P17
P16
15
14
13
12
11
10
9
8
P15
P14
P13
P12
P11
P10
P9
P8
7
6
5
4
3
2
1
0
P7
P6
P5
P4
P3
P2
P1
P0
• P0-31: Output Driver Enable
0: The output driver is disabled for the corresponding pin.
1: The output driver is enabled for the corresponding pin.
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20.6.6
Name:
Output Value Register
OVR
Access Type:
Read, Write, Set, Clear, Toggle
Offset:
0x50, 0x54, 0x58, 0x5C
Reset Value:
-
31
30
29
28
27
26
25
24
P31
P30
P29
P28
P27
P26
P25
P24
23
22
21
20
19
18
17
16
P23
P22
P21
P20
P19
P18
P17
P16
15
14
13
12
11
10
9
8
P15
P14
P13
P12
P11
P10
P9
P8
7
6
5
4
3
2
1
0
P7
P6
P5
P4
P3
P2
P1
P0
• P0-31: Output Value
0: The value to be driven on the I/O line is 0.
1: The value to be driven on the I/O line is 1.
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20.6.7
Name:
Pin Value Register
PVR
Access Type:
Read
Offset:
0x60, 0x64, 0x68, 0x6C
Reset Value:
-
31
30
29
28
27
26
25
24
P31
P30
P29
P28
P27
P26
P25
P24
23
22
21
20
19
18
17
16
P23
P22
P21
P20
P19
P18
P17
P16
15
14
13
12
11
10
9
8
P15
P14
P13
P12
P11
P10
P9
P8
7
6
5
4
3
2
1
0
P7
P6
P5
P4
P3
P2
P1
P0
• P0-31: Pin Value
0: The I/O line is at level ‘0’.
1: The I/O line is at level ‘1’.
Note that the level of a pin can only be read when GPER is set or interrupt is enabled for the pin.
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20.6.8
Name:
Pull-up Enable Register
PUER
Access Type:
Read, Write, Set, Clear, Toggle
Offset:
0x70, 0x74, 0x78, 0x7C
Reset Value:
-
31
30
29
28
27
26
25
24
P31
P30
P29
P28
P27
P26
P25
P24
23
22
21
20
19
18
17
16
P23
P22
P21
P20
P19
P18
P17
P16
15
14
13
12
11
10
9
8
P15
P14
P13
P12
P11
P10
P9
P8
7
6
5
4
3
2
1
0
P7
P6
P5
P4
P3
P2
P1
P0
• P0-31: Pull-up Enable
0: The internal pull-up resistor is disabled for the corresponding pin.
1: The internal pull-up resistor is enabled for the corresponding pin.
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20.6.9
Name:
Interrupt Enable Register
IER
Access Type:
Read, Write, Set, Clear, Toggle
Offset:
0x90, 0x94, 0x98, 0x9C
Reset Value:
-
31
30
29
28
27
26
25
24
P31
P30
P29
P28
P27
P26
P25
P24
23
22
21
20
19
18
17
16
P23
P22
P21
P20
P19
P18
P17
P16
15
14
13
12
11
10
9
8
P15
P14
P13
P12
P11
P10
P9
P8
7
6
5
4
3
2
1
0
P7
P6
P5
P4
P3
P2
P1
P0
• P0-31: Interrupt Enable
0: Interrupt is disabled for the corresponding pin.
1: Interrupt is enabled for the corresponding pin.
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20.6.10
Name:
Interrupt Mode Register 0
IMR0
Access Type:
Read, Write, Set, Clear, Toggle
Offset:
0xA0, 0xA4, 0xA8, 0xAC
Reset Value:
-
31
30
29
28
27
26
25
24
P31
P30
P29
P28
P27
P26
P25
P24
23
22
21
20
19
18
17
16
P23
P22
P21
P20
P19
P18
P17
P16
15
14
13
12
11
10
9
8
P15
P14
P13
P12
P11
P10
P9
P8
7
6
5
4
3
2
1
0
P7
P6
P5
P4
P3
P2
P1
P0
• P0-31: Interrupt Mode Bit 0
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20.6.11
Name:
Interrupt Mode Register 1
IMR1
Access Type:
Read, Write, Set, Clear, Toggle
Offset:
0xB0, 0xB4, 0xB8, 0xBC
Reset Value:
-
31
30
29
28
27
26
P31
P30
P29
P28
P27
P26
25
24
P25
P24
23
22
21
20
19
18
17
16
P23
P22
P21
P20
P19
P18
P17
P16
15
14
13
12
11
10
9
8
P15
P14
P13
P12
P11
P10
P9
P8
7
6
5
4
3
2
1
0
P7
P6
P5
P4
P3
P2
P1
P0
• P0-31: Interrupt Mode Bit 1
{IMR1, IMR0}
00
01
10
11
Interrupt Mode
Pin Change
Rising Edge
Falling Edge
Reserved
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20.6.12
Name:
Glitch Filter Enable Register
GFER
Access Type:
Read, Write, Set, Clear, Toggle
Offset:
0xC0, 0xC4, 0xC8, 0xCC
Reset Value:
-
31
30
29
28
27
26
P31
P30
P29
P28
P27
P26
25
24
P25
P24
23
22
21
20
19
18
17
16
P23
P22
P21
P20
P19
P18
P17
P16
15
14
13
12
11
10
9
8
P15
P14
P13
P12
P11
P10
P9
P8
7
6
5
4
3
2
1
0
P7
P6
P5
P4
P3
P2
P1
P0
• P0-31: Glitch Filter Enable
0: Glitch filter is disabled for the corresponding pin.
1: Glitch filter is enabled for the corresponding pin.
NOTE! The value of this register should only be changed when IER is ‘0’. Updating this GFER while interrupt on the
corresponding pin is enabled can cause an unintentional interrupt to be triggered.
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20.6.13
Name:
Interrupt Flag Register
IFR
Access Type:
Read, Clear
Offset:
0xD0, 0xD8
Reset Value:
-
31
30
29
28
27
26
P31
P30
P29
P28
P27
P26
25
24
P25
P24
23
22
21
20
19
18
17
16
P23
P22
P21
P20
P19
P18
P17
P16
15
14
13
12
11
10
9
8
P15
P14
P13
P12
P11
P10
P9
P8
7
6
5
4
3
2
1
0
P7
P6
P5
P4
P3
P2
P1
P0
• P0-31: Interrupt Flag
1: An interrupt condition has been detected on the corresponding pin.
0: No interrupt condition has beedn detected on the corresponding pin since reset or the last time it was cleared.
The number of interrupt request lines is dependant on the number of I/O pins on the MCU. Refer to the product specific data for
details. Note also that a bit in the Interrupt Flag register is only valid if the corresponding bit in IER is set.
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20.7
20.7.1
Programming Examples
8-bit LED-Chaser
// Set R0 to GPIO base address
mov
R0, LO(AVR32_GPIO_ADDRESS)
orh
R0, HI(AVR32_GPIO_ADDRESS)
// Enable GPIO control of pin 0-8
mov
R1, 0xFF
st.w
R0[AVR32_GPIO_GPERS], R1
// Set initial value of port
mov
R2, 0x01
st.w
R0[AVR32_GPIO_OVRS], R2
// Set up toggle value. Two pins are toggled
// in each round. The bit that is currently set,
// and the next bit to be set.
mov
R2, 0x0303
orh
R2, 0x0303
loop:
// Only change 8 LSB
mov
R3, 0x00FF
and
R3, R2
st.w
R0[AVR32_GPIO_OVRT], R3
rol
R2
rcall
delay
rjmp
loop
It is assumed in this example that a subroutine "delay" exists that returns after a given time.
20.7.2
Configuration of USART pins
The example below shows how to configure a peripheral module to control I/O pins. It assumed
in this example that the USART receive pin (RXD) is connected to PC16 and that the USART
transmit pin (TXD) is connected to PC17. For both pins, the USART is peripheral B. In this
example, the state of the GPIO registers is assumed to be unknown. The two USART pins are
therefore first set to be controlled by the GPIO with output drivers disabled. The pins can then be
assured to be tri-stated while changing the Peripheral Mux Registers.
// Set up pointer to GPIO, PORTC
mov
R0, LO(AVR32_GPIO_ADDRESS + PORTC_OFFSET)
orh
R0, HI(AVR32_GPIO_ADDRESS + PORTC_OFFSET)
// Disable output drivers
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mov
R1, 0x0000
orh
R1, 0x0003
st.w
R0[AVR32_GPIO_ODERC], R1
// Make the GPIO control the pins
st.w
R0[AVR32_GPIO_GPERS], R1
// Select peripheral B on PC16-PC17
st.w
R0[AVR32_GPIO_PMR0S], R1
st.w
R0[AVR32_GPIO_PMR1C], R1
// Enable peripheral control
st.w
R0[AVR32_GPIO_GPERC], R1
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20.8
Module configuration
The specific configuration for each GPIO instance is listed in the following tables.The module
bus clocks listed here are connected to the system bus clocks according to the table in the System Bus Clock Connections section.
Table 20-2.
Module configuration
Feature
GPIO
Number of GPIO ports
4
Number of peripheral functions
4
Table 20-3.
Module clock name
Module name
Clock name
GPIO
CLK_GPIO
The reset values for all GPIO registers are zero with the following exceptions:
Table 20-4.
Register Reset Values
Port
Register
Reset Value
0
GPER
0xFFFFFFFF
0
GFER
0xFFFFFFFF
1
GPER
0xFFFFFFFF
1
GFER
0xFFFFFFFF
2
GPER
0xFFFFFFFF
2
GFER
0xFFFFFFFF
3
GPER
0x00007FFF
3
GFER
0x00007FFF
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21. Serial Peripheral Interface (SPI)
Rev. 2.1.0.1
21.1
Features
• Compatible with an embedded 32-bit microcontroller
• Supports communication with serial external devices
– Four chip selects with external decoder support allow communication with up to 15
peripherals
– Serial memories, such as DataFlash and 3-wire EEPROMs
– Serial peripherals, such as ADCs, DACs, LCD controllers, CAN controllers and Sensors
– External co-processors
• Master or Slave Serial Peripheral Bus Interface
– 4 - to 16-bit programmable data length per chip select
– Programmable phase and polarity per chip select
– Programmable transfer delays between consecutive transfers and between clock and data
per chip select
– Programmable delay between consecutive transfers
– Selectable mode fault detection
• Connection to Peripheral DMA Controller channel capabilities optimizes data transfers
– One channel for the receiver, one channel for the transmitter
– Next buffer support
– Four character FIFO in reception
21.2
Overview
The Serial Peripheral Interface (SPI) circuit is a synchronous serial data link that provides communication with external devices in Master or Slave mode. It also enables communication
between processors if an external processor is connected to the system.
The Serial Peripheral Interface is essentially a shift register that serially transmits data bits to
other SPIs. During a data transfer, one SPI system acts as the “master”' which controls the data
flow, while the other devices act as “slaves'' which have data shifted into and out by the master.
Different CPUs can take turn being masters (Multiple Master Protocol opposite to Single Master
Protocol where one CPU is always the master while all of the others are always slaves) and one
master may simultaneously shift data into multiple slaves. However, only one slave may drive its
output to write data back to the master at any given time.
A slave device is selected when the master asserts its NSS signal. If multiple slave devices
exist, the master generates a separate slave select signal for each slave (NPCS).
The SPI system consists of two data lines and two control lines:
• Master Out Slave In (MOSI): this data line supplies the output data from the master shifted
into the input(s) of the slave(s).
• Master In Slave Out (MISO): this data line supplies the output data from a slave to the input of
the master. There may be no more than one slave transmitting data during any particular
transfer.
• Serial Clock (SPCK): this control line is driven by the master and regulates the flow of the
data bits. The master may transmit data at a variety of baud rates; the SPCK line cycles once
for each bit that is transmitted.
• Slave Select (NSS): this control line allows slaves to be turned on and off by hardware.
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21.3
Block Diagram
Figure 21-1. SPI Block Diagram
Peripheral DMA
Controller
Peripheral Bus
SPCK
MISO
CLK_SPI
MOSI
Spi Interface
I/O
Controller
NPCS0/NSS
NPCS1
NPCS2
Interrupt Control
NPCS3
SPI Interrupt
21.4
Application Block Diagram
Figure 21-2. Application Block Diagram: Single Master/Multiple Slave Implementation
Spi Master
SPCK
SPCK
MISO
MISO
MOSI
MOSI
NPCS0
Slave 0
NSS
NPCS1
NPCS2
NPCS3
NC
SPCK
MISO
MOSI
Slave 1
NSS
SPCK
MISO
MOSI
Slave 2
NSS
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21.5
I/O Lines Description
Table 21-1.
I/O Lines Description
Type
21.6
Pin Name
Pin Description
Master
Slave
MISO
Master In Slave Out
Input
Output
MOSI
Master Out Slave In
Output
Input
SPCK
Serial Clock
Output
Input
NPCS1-NPCS3
Peripheral Chip Selects
Output
Unused
NPCS0/NSS
Peripheral Chip Select/Slave Select
Output
Input
Product Dependencies
In order to use this module, other parts of the system must be configured correctly, as described
below.
21.6.1
I/O Lines
The pins used for interfacing the compliant external devices may be multiplexed with I/O lines.
The user must first configure the I/O Controller to assign the SPI pins to their peripheral
functions.
21.6.2
Clocks
The clock for the SPI bus interface (CLK_SPI) is generated by the Power Manager. This clock is
enabled at reset, and can be disabled in the Power Manager. It is recommended to disable the
SPI before disabling the clock, to avoid freezing the SPI in an undefined state.
21.6.3
Interrupts
The SPI interrupt request line is connected to the interrupt controller. Using the SPI interrupt
requires the interrupt controller to be programmed first.
21.7
21.7.1
Functional Description
Modes of Operation
The SPI operates in master mode or in slave mode.
Operation in master mode is configured by writing a one to the Master/Slave Mode bit in the
Mode Register (MR.MSTR). The pins NPCS0 to NPCS3 are all configured as outputs, the SPCK
pin is driven, the MISO line is wired on the receiver input and the MOSI line driven as an output
by the transmitter.
If the MR.MSTR bit is written to zero, the SPI operates in slave mode. The MISO line is driven by
the transmitter output, the MOSI line is wired on the receiver input, the SPCK pin is driven by the
transmitter to synchronize the receiver. The NPCS0 pin becomes an input, and is used as a
Slave Select signal (NSS). The pins NPCS1 to NPCS3 are not driven and can be used for other
purposes.
The data transfers are identically programmable for both modes of operations. The baud rate
generator is activated only in master mode.
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21.7.2
Data Transfer
Four combinations of polarity and phase are available for data transfers. The clock polarity is
configured with the Clock Polarity bit in the Chip Select Registers (CSRn.CPOL). The clock
phase is configured with the Clock Phase bit in the CSRn registers (CSRn.NCPHA). These two
bits determine the edges of the clock signal on which data is driven and sampled. Each of the
two bits has two possible states, resulting in four possible combinations that are incompatible
with one another. Thus, a master/slave pair must use the same parameter pair values to communicate. If multiple slaves are used and fixed in different configurations, the master must
reconfigure itself each time it needs to communicate with a different slave.
Table 21-2 on page 404 shows the four modes and corresponding parameter settings.
Table 21-2.
SPI modes
SPI Mode
CPOL
NCPHA
0
0
1
1
0
0
2
1
1
3
1
0
Figure 21-3 on page 404 and Figure 21-4 on page 405 show examples of data transfers.
Figure 21-3. SPI Transfer Format (NCPHA = 1, 8 bits per transfer)
SPCK cycle (for reference)
2
1
3
4
5
6
7
8
SPCK
(CPOL = 0)
SPCK
(CPOL = 1)
MOSI
(from master)
MISO
(from slave)
MSB
MSB
6
5
4
3
2
1
LSB
6
5
4
3
2
1
LSB
***
NSS
(to slave)
*** Not Defined, but normaly MSB of previous character received
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Figure 21-4. SPI Transfer Format (NCPHA = 0, 8 bits per transfer)
SPCK cycle (for reference)
1
2
3
4
5
6
7
8
SPCK
(CPOL = 0)
SPCK
(CPOL = 1)
MOSI
(from master)
MISO
(from slave)
***
MSB
6
5
4
3
2
1
MSB
6
5
4
3
2
1
LSB
LSB
NSS
(to slave)
*** Not Defined, but normaly LSB of previous character transmitted
21.7.3
Master Mode Operations
When configured in master mode, the SPI uses the internal programmable baud rate generator
as clock source. It fully controls the data transfers to and from the slave(s) connected to the SPI
bus. The SPI drives the chip select line to the slave and the serial clock signal (SPCK).
The SPI features two holding registers, the Transmit Data Register (TDR) and the Receive Data
Register (RDR), and a single Shift Register. The holding registers maintain the data flow at a
constant rate.
After enabling the SPI, a data transfer begins when the processor writes to the TDR register.
The written data is immediately transferred in the Shift Register and transfer on the SPI bus
starts. While the data in the Shift Register is shifted on the MOSI line, the MISO line is sampled
and shifted in the Shift Register. Transmission cannot occur without reception.
Before writing to the TDR, the Peripheral Chip Select field in TDR (TDR.PCS) must be written in
order to select a slave.
If new data is written to TDR during the transfer, it stays in it until the current transfer is completed. Then, the received data is transferred from the Shift Register to RDR, the data in TDR is
loaded in the Shift Register and a new transfer starts.
The transfer of a data written in TDR in the Shift Register is indicated by the Transmit Data Register Empty bit in the Status Register (SR.TDRE). When new data is written in TDR, this bit is
cleared. The SR.TDRE bit is used to trigger the Transmit Peripheral DMA Controller channel.
The end of transfer is indicated by the Transmission Registers Empty bit in the SR register
(SR.TXEMPTY). If a transfer delay (CSRn.DLYBCT) is greater than zero for the last transfer,
SR.TXEMPTY is set after the completion of said delay. The CLK_SPI can be switched off at this
time.
During reception, received data are transferred from the Shift Register to the reception FIFO.
The FIFO can contain up to 4 characters (both Receive Data and Peripheral Chip Select fields).
While a character of the FIFO is unread, the Receive Data Register Full bit in SR remains high
(SR.RDRF). Characters are read through the RDR register. If the four characters stored in the
FIFO are not read and if a new character is stored, this sets the Overrun Error Status bit in the
SR register (SR.OVRES). The procedure to follow in such a case is described in Section
21.7.3.8.
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In master mode, if the received data is not read fast enough compared to the transfer rhythm
imposed by the write accesses in the TDR, some overrun errors may occur, even if the FIFO is
enabled. To insure a perfect data integrity of received data (especially at high data rate), the
mode Wait Data Read Before Transfer can be enabled in the MR register (MR.WDRBT). When
this mode is activated, no transfer starts while received data remains unread in the RDR. When
data is written to the TDR and if unread received data is stored in the RDR, the transfer is
paused until the RDR is read. In this mode no overrun error can occur. Please note that if this
mode is enabled, it is useless to activate the FIFO in reception.
Figure 21-5 on page 406shows a block diagram of the SPI when operating in master mode. Figure 21-6 on page 407 shows a flow chart describing how transfers are handled.
21.7.3.1
Master mode block diagram
Figure 21-5. Master Mode Block Diagram
CSR0..3
SCBR
CLK_SPI
Baud Rate Generator
SPCK
SPI
Clock
RXFIFOEN
RDR
RDRF
OVRES
RD
CSR0..3
BITS
NCPHA
CPOL
LSB
MISO
0
1
MSB
Shift Register
TDR
4 – Character FIFO
TD
MOSI
TDRE
RXFIFOEN
RDR
PCS
CSR0..3
CSNAAT
CSAAT
PS
MR
0
1
4 – Character FIFO
NPCS3
PCSDEC
PCS
0
TDR
NPCS2
Current
Peripheral
NPCS1
PCS
NPCS0
1
MSTR
MODF
NPCS0
MODFDIS
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21.7.3.2
Master mode flow diagram
Figure 21-6. Master Mode Flow Diagram
SPI Enable
- NPCS defines the current Chip Select
- CSAAT, DLYBS, DLYBCT refer to the fields of the
Chip Select Register corresponding to the Current Chip Select
- When NPCS is 0xF, CSAAT is 0.
1
TDRE ?
0
1
CSAAT ?
PS ?
0
1
0
Fixed
peripheral
PS ?
1
Fixed
peripheral
0
Variable
peripheral
Variable
peripheral
TDR(PCS)
= NPCS ?
no
NPCS = TDR(PCS)
NPCS = MR(PCS)
yes
MR(PCS)
= NPCS ?
no
NPCS = 0xF
NPCS = 0xF
Delay DLYBCS
Delay DLYBCS
NPCS = TDR(PCS)
NPCS = MR(PCS),
TDR(PCS)
Delay DLYBS
Serializer = TDR(TD)
TDRE = 1
Data Transfer
RDR(RD) = Serializer
RDRF = 1
Delay DLYBCT
0
TDRE ?
1
1
CSAAT ?
0
NPCS = 0xF
Delay DLYBCS
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21.7.3.3
Clock generation
The SPI Baud rate clock is generated by dividing the CLK_SPI , by a value between 1 and 255.
This allows a maximum operating baud rate at up to CLK_SPI and a minimum operating baud
rate of CLK_SPI divided by 255.
Writing the Serial Clock Baud Rate field in the CSRn registers (CSRn.SCBR) to zero is forbidden. Triggering a transfer while CSRn.SCBR is zero can lead to unpredictable results.
At reset, CSRn.SCBR is zero and the user has to configure it at a valid value before performing
the first transfer.
The divisor can be defined independently for each chip select, as it has to be configured in the
CSRn.SCBR field. This allows the SPI to automatically adapt the baud rate for each interfaced
peripheral without reprogramming.
21.7.3.4
Transfer delays
Figure 21-7 on page 408 shows a chip select transfer change and consecutive transfers on the
same chip select. Three delays can be configured to modify the transfer waveforms:
• The delay between chip selects, programmable only once for all the chip selects by writing to
the Delay Between Chip Selects field in the MR register (MR.DLYBCS). Allows insertion of a
delay between release of one chip select and before assertion of a new one.
• The delay before SPCK, independently programmable for each chip select by writing the
Delay Before SPCK field in the CSRn registers (CSRn.DLYBS). Allows the start of SPCK to
be delayed after the chip select has been asserted.
• The delay between consecutive transfers, independently programmable for each chip select
by writing the Delay Between Consecutive Transfers field in the CSRn registers
(CSRn.DLYBCT). Allows insertion of a delay between two transfers occurring on the same
chip select
These delays allow the SPI to be adapted to the interfaced peripherals and their speed and bus
release time.
Figure 21-7. Programmable Delays
Chip Select 1
Chip Select 2
SPCK
DLYBCS
DLYBS
DLYBCT
DLYBCT
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21.7.3.5
Peripheral selection
The serial peripherals are selected through the assertion of the NPCS0 to NPCS3 signals. By
default, all the NPCS signals are high before and after each transfer.
The peripheral selection can be performed in two different ways:
• Fixed Peripheral Select: SPI exchanges data with only one peripheral
• Variable Peripheral Select: Data can be exchanged with more than one peripheral
Fixed Peripheral Select is activated by writing a zero to the Peripheral Select bit in MR (MR.PS).
In this case, the current peripheral is defined by the MR.PCS field and the TDR.PCS field has no
effect.
Variable Peripheral Select is activated by writing a one to the MR.PS bit . The TDR.PCS field is
used to select the current peripheral. This means that the peripheral selection can be defined for
each new data.
The Fixed Peripheral Selection allows buffer transfers with a single peripheral. Using the Peripheral DMA Controller is an optimal means, as the size of the data transfer between the memory
and the SPI is either 4 bits or 16 bits. However, changing the peripheral selection requires the
Mode Register to be reprogrammed.
The Variable Peripheral Selection allows buffer transfers with multiple peripherals without reprogramming the MR register. Data written to TDR is 32-bits wide and defines the real data to be
transmitted and the peripheral it is destined to. Using the Peripheral DMA Controller in this mode
requires 32-bit wide buffers, with the data in the LSBs and the PCS and LASTXFER fields in the
MSBs, however the SPI still controls the number of bits (8 to16) to be transferred through MISO
and MOSI lines with the CSRn registers. This is not the optimal means in term of memory size
for the buffers, but it provides a very effective means to exchange data with several peripherals
without any intervention of the processor.
21.7.3.6
Peripheral chip select decoding
The user can configure the SPI to operate with up to 15 peripherals by decoding the four Chip
Select lines, NPCS0 to NPCS3 with an external logic. This can be enabled by writing a one to
the Chip Select Decode bit in the MR register (MR.PCSDEC).
When operating without decoding, the SPI makes sure that in any case only one chip select line
is activated, i.e. driven low at a time. If two bits are defined low in a PCS field, only the lowest
numbered chip select is driven low.
When operating with decoding, the SPI directly outputs the value defined by the PCS field of
either the MR register or the TDR register (depending on PS).
As the SPI sets a default value of 0xF on the chip select lines (i.e. all chip select lines at one)
when not processing any transfer, only 15 peripherals can be decoded.
The SPI has only four Chip Select Registers, not 15. As a result, when decoding is activated,
each chip select defines the characteristics of up to four peripherals. As an example, the CRS0
register defines the characteristics of the externally decoded peripherals 0 to 3, corresponding to
the PCS values 0x0 to 0x3. Thus, the user has to make sure to connect compatible peripherals
on the decoded chip select lines 0 to 3, 4 to 7, 8 to 11 and 12 to 14.
21.7.3.7
Peripheral deselection
When operating normally, as soon as the transfer of the last data written in TDR is completed,
the NPCS lines all rise. This might lead to runtime error if the processor is too long in responding
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to an interrupt, and thus might lead to difficulties for interfacing with some serial peripherals
requiring the chip select line to remain active during a full set of transfers.
To facilitate interfacing with such devices, the CSRn registers can be configured with the Chip
Select Active After Transfer bit written to one (CSRn.CSAAT) . This allows the chip select lines
to remain in their current state (low = active) until transfer to another peripheral is required.
When the CSRn.CSAAT bit is written to qero, the NPCS does not rise in all cases between two
transfers on the same peripheral. During a transfer on a Chip Select, the SR.TDRE bit rises as
soon as the content of the TDR is transferred into the internal shifter. When this bit is detected
the TDR can be reloaded. If this reload occurs before the end of the current transfer and if the
next transfer is performed on the same chip select as the current transfer, the Chip Select is not
de-asserted between the two transfers. This might lead to difficulties for interfacing with some
serial peripherals requiring the chip select to be de-asserted after each transfer. To facilitate
interfacing with such devices, the CSRn registers can be configured with the Chip Select Not
Active After Transfer bit (CSRn.CSNAAT) written to one. This allows to de-assert systematically
the chip select lines during a time DLYBCS. (The value of the CSRn.CSNAAT bit is taken into
account only if the CSRn.CSAAT bit is written to zero for the same Chip Select).
Figure 21-8 on page 411 shows different peripheral deselection cases and the effect of the
CSRn.CSAAT and CSRn.CSNAAT bits.
21.7.3.8
FIFO management
A FIFO has been implemented in Reception FIFO (both in master and in slave mode), in order to
be able to store up to 4 characters without causing an overrun error. If an attempt is made to
store a fifth character, an overrun error rises. If such an event occurs, the FIFO must be flushed.
There are two ways to Flush the FIFO:
• By performing four read accesses of the RDR (the data read must be ignored)
• By writing a one to the Flush Fifo Command bit in the CR register (CR.FLUSHFIFO).
After that, the SPI is able to receive new data.
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Figure 21-8. Peripheral Deselection
CSAAT = 0 and CSNAAT = 0
TDRE
CSAAT = 1 and CSNAAT= 0 / 1
DLYBCT
NPCS[0..3]
DLYBCT
A
A
A
A
DLYBCS
A
DLYBCS
PCS = A
PCS = A
Write TDR
TDRE
DLYBCT
DLYBCT
A
NPCS[0..3]
A
A
A
DLYBCS
A
DLYBCS
PCS=A
PCS = A
Write TDR
TDRE
DLYBCT
NPCS[0..3]
DLYBCT
A
B
B
A
DLYBCS
DLYBCS
PCS = B
PCS = B
Write TDR
CSAAT = 0 and CSNAAT = 0
CSAAT = 0 and CSNAAT = 1
DLYBCT
DLYBCT
TDRE
A
NPCS[0..3]
A
A
A
DLYBCS
PCS = A
PCS = A
Write TDR
Figure 21-8 on page 411 shows different peripheral deselection cases and the effect of the
CSRn.CSAAT and CSRn.CSNAAT bits.
21.7.4
SPI Slave Mode
When operating in slave mode, the SPI processes data bits on the clock provided on the SPI
clock pin (SPCK).
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The SPI waits for NSS to go active before receiving the serial clock from an external master.
When NSS falls, the clock is validated on the serializer, which processes the number of bits
defined by the Bits Per Transfer field of the Chip Select Register 0 (CSR0.BITS). These bits are
processed following a phase and a polarity defined respectively by the CSR0.NCPHA and
CSR0.CPOL bits. Note that the BITS, CPOL, and NCPHA bits of the other Chip Select Registers
have no effect when the SPI is configured in Slave Mode.
The bits are shifted out on the MISO line and sampled on the MOSI line.
When all the bits are processed, the received data is transferred in the Receive Data Register
and the SR.RDRF bit rises. If the RDR register has not been read before new data is received,
the SR.OVRES bit is set. As long as this bit is set, data is loaded in RDR. The user has to read
the SR register to clear the SR.OVRES bit.
When a transfer starts, the data shifted out is the data present in the Shift Register. If no data
has been written in the TDR register, the last data received is transferred. If no data has been
received since the last reset, all bits are transmitted low, as the Shift Register resets to zero.
When a first data is written in TDR, it is transferred immediately in the Shift Register and the
SR.TDRE bit rises. If new data is written, it remains in TDR until a transfer occurs, i.e. NSS falls
and there is a valid clock on the SPCK pin. When the transfer occurs, the last data written in
TDR is transferred in the Shift Register and the SR.TDRE bit rises. This enables frequent
updates of critical variables with single transfers.
Then, a new data is loaded in the Shift Register from the TDR. In case no character is ready to
be transmitted, i.e. no character has been written in TDR since the last load from TDR to the
Shift Register, the Shift Register is not modified and the last received character is retransmitted.
In this case the Underrun Error Status bit is set in SR (SR.UNDES).
Figure 21-9 on page 413 shows a block diagram of the SPI when operating in slave mode.
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Figure 21-9. Slave Mode Functional Block Diagram
SPCK
SPI
Clock
NSS
SPIEN
RXFIFOEN
SPIENS
RDR
SPIDIS
RDRF
OVRES
RD
CSR0
BITS
NCPHA
CPOL
MOSI
LSB
0
1
4 - Character FIFO
MSB
Shift Register
MISO
UNDES
TDR
TD
TDRE
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21.8
User Interface
Table 21-3.
Note:
SPI Register Memory Map
Offset
Register
Register Name
Access
Reset
0x00
Control Register
CR
Write-only
0x00000000
0x04
Mode Register
MR
Read/Write
0x00000000
0x08
Receive Data Register
RDR
Read-only
0x00000000
0x0C
Transmit Data Register
TDR
Write-only
0x00000000
0x10
Status Register
SR
Read-only
0x000000F0
0x14
Interrupt Enable Register
IER
Write-only
0x00000000
0x18
Interrupt Disable Register
IDR
Write-only
0x00000000
0x1C
Interrupt Mask Register
IMR
Read-only
0x00000000
0x30
Chip Select Register 0
CSR0
Read/Write
0x00000000
0x34
Chip Select Register 1
CSR1
Read/Write
0x00000000
0x38
Chip Select Register 2
CSR2
Read/Write
0x00000000
0x3C
Chip Select Register 3
CSR3
Read/Write
0x00000000
0x E4
Write Protection Control Register
WPCR
Read/Write
0X00000000
0xE8
Write Protection Status Register
WPSR
Read-only
0x00000000
0xFC
Version Register
VERSION
Read-only
- (1)
1. The reset values are device specific. Please refer to the Module Configuration section at the end of this chapter.
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21.8.1
Name:
Control Register
CR
Access Type:
Write-only
Offset:
0x00
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
LASTXFER
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
FLUSHFIFO
7
6
5
4
3
2
1
0
SWRST
-
-
-
-
-
SPIDIS
SPIEN
• LASTXFER: Last Transfer
1: The current NPCS will be deasserted after the character written in TD has been transferred. When CSRn.CSAAT is one, this
allows to close the communication with the current serial peripheral by raising the corresponding NPCS line as soon as TD
transfer has completed.
0: Writing a zero to this bit has no effect.
• FLUSHFIFO: Flush Fifo Command
1: If The FIFO Mode is enabled (MR.FIFOEN written to one) and if an overrun error has been detected, this command allows to
empty the FIFO.
0: Writing a zero to this bit has no effect.
• SWRST: SPI Software Reset
1: Writing a one to this bit will reset the SPI. A software-triggered hardware reset of the SPI interface is performed. The SPI is in
slave mode after software reset. Peripheral DMA Controller channels are not affected by software reset.
0: Writing a zero to this bit has no effect.
• SPIDIS: SPI Disable
1: Writing a one to this bit will disable the SPI. As soon as SPIDIS is written to one, the SPI finishes its transfer, all pins are set
in input mode and no data is received or transmitted. If a transfer is in progress, the transfer is finished before the SPI is
disabled. If both SPIEN and SPIDIS are equal to one when the CR register is written, the SPI is disabled.
0: Writing a zero to this bit has no effect.
• SPIEN: SPI Enable
1: Writing a one to this bit will enable the SPI to transfer and receive data.
0: Writing a zero to this bit has no effect.
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21.8.2
Name:
Mode Register
MR
Access Type:
Read/Write
Offset:
0x04
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
DLYBCS
23
22
21
20
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
LLB
RXFIFOEN
WDRBT
-
-
PCSDEC
PS
MSTR
PCS
• DLYBCS: Delay Between Chip Selects
This field defines the delay from NPCS inactive to the activation of another NPCS. The DLYBCS time guarantees nonoverlapping chip selects and solves bus contentions in case of peripherals having long data float times.
If DLYBCS is less than or equal to six, six CLK_SPI periods will be inserted by default.
Otherwise, the following equation determines the delay:
Delay Between Chip Selects = DLYBCS
----------------------CLKSPI
• PCS: Peripheral Chip Select
This field is only used if Fixed Peripheral Select is active (PS = 0).
If PCSDEC = 0:
PCS = xxx0NPCS[3:0] = 1110
PCS = xx01NPCS[3:0] = 1101
PCS = x011NPCS[3:0] = 1011
PCS = 0111NPCS[3:0] = 0111
PCS = 1111forbidden (no peripheral is selected)
(x = don’t care)
If PCSDEC = 1:
NPCS[3:0] output signals = PCS.
• LLB: Local Loopback Enable
1: Local loopback path enabled. LLB controls the local loopback on the data serializer for testing in master mode only (MISO is
internally connected on MOSI).
0: Local loopback path disabled.
• RXFIFOEN: FIFO in Reception Enable
1: The FIFO is used in reception (four characters can be stored in the SPI).
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0: The FIFO is not used in reception (only one character can be stored in the SPI).
• WDRBT: Wait Data Read Before Transfer
1: In master mode, a transfer can start only if the RDR register is empty, i.e. does not contain any unread data. This mode
prevents overrun error in reception.
0: No Effect. In master mode, a transfer can be initiated whatever the state of the RDR register is.
• PCSDEC: Chip Select Decode
0: The chip selects are directly connected to a peripheral device.
1: The four chip select lines are connected to a 4- to 16-bit decoder.
When PCSDEC equals one, up to 15 Chip Select signals can be generated with the four lines using an external 4- to 16-bit
decoder. The CSRn registers define the characteristics of the 15 chip selects according to the following rules:
CSR0 defines peripheral chip select signals 0 to 3.
CSR1 defines peripheral chip select signals 4 to 7.
CSR2 defines peripheral chip select signals 8 to 11.
CSR3 defines peripheral chip select signals 12 to 14.
• PS: Peripheral Select
1: Variable Peripheral Select.
0: Fixed Peripheral Select.
• MSTR: Master/Slave Mode
1: SPI is in master mode.
0: SPI is in slave mode.
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21.8.3
Name:
Receive Data Register
RDR
Access Type:
Read-only
Offset:
0x08
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
15
14
13
12
PCS
11
10
9
8
3
2
1
0
RD[15:8]
7
6
5
4
RD[7:0]
• PCS: Peripheral Chip Select
In master mode only, these bits indicate the value on the NPCS pins at the end of a transfer. Otherwise, these bits read zero.
• RD: Receive Data
Data received by the SPI Interface is stored in this register right-justified. Unused bits read zero.
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21.8.4
Name:
Transmit Data Register
TDR
Access Type:
Write-only
Offset:
0x0C
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
LASTXFER
23
22
21
20
19
18
17
16
-
-
-
-
15
14
13
12
PCS
11
10
9
8
3
2
1
0
TD[15:8]
7
6
5
4
TD[7:0]
• LASTXFER: Last Transfer
1: The current NPCS will be deasserted after the character written in TD has been transferred. When CSRn.CSAAT is one, this
allows to close the communication with the current serial peripheral by raising the corresponding NPCS line as soon as TD
transfer has completed.
0: Writing a zero to this bit has no effect.
This field is only used if Variable Peripheral Select is active (MR.PS = 1).
• PCS: Peripheral Chip Select
If PCSDEC = 0:
PCS = xxx0NPCS[3:0] = 1110
PCS = xx01NPCS[3:0] = 1101
PCS = x011NPCS[3:0] = 1011
PCS = 0111NPCS[3:0] = 0111
PCS = 1111forbidden (no peripheral is selected)
(x = don’t care)
If PCSDEC = 1:
NPCS[3:0] output signals = PCS
This field is only used if Variable Peripheral Select is active (MR.PS = 1).
• TD: Transmit Data
Data to be transmitted by the SPI Interface is stored in this register. Information to be transmitted must be written to the TDR
register in a right-justified format.
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21.8.5
Name:
Status Register
SR
Access Type:
Read-only
Offset:
0x10
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
SPIENS
15
14
13
12
11
10
9
8
-
-
-
-
-
UNDES
TXEMPTY
NSSR
7
6
5
4
3
2
1
0
-
-
-
-
OVRES
-
TDRE
RDRF
• SPIENS: SPI Enable Status
1: This bit is set when the SPI is enabled.
0: This bit is cleared when the SPI is disabled.
• UNDES: Underrun Error Status (Slave Mode Only)
1: This bit is set when a transfer begins whereas no data has been loaded in the TDR register.
0: This bit is cleared when the SR register is read.
• TXEMPTY: Transmission Registers Empty
1: This bit is set when TDR and internal shifter are empty. If a transfer delay has been defined, TXEMPTY is set after the
completion of such delay.
0: This bit is cleared as soon as data is written in TDR.
• NSSR: NSS Rising
1: A rising edge occurred on NSS pin since last read.
0: This bit is cleared when the SR register is read.
• OVRES: Overrun Error Status
1: This bit is set when an overrun has occurred. An overrun occurs when RDR is loaded at least twice from the serializer since
the last read of the RDR.
0: This bit is cleared when the SR register is read.
• TDRE: Transmit Data Register Empty
1: This bit is set when the last data written in the TDR register has been transferred to the serializer.
0: This bit is cleared when data has been written to TDR and not yet transferred to the serializer.
TDRE equals zero when the SPI is disabled or at reset. The SPI enable command sets this bit to one.
• RDRF: Receive Data Register Full
1: Data has been received and the received data has been transferred from the serializer to RDR since the last read of RDR.
0: No data has been received since the last read of RDR
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21.8.6
Name:
Interrupt Enable Register
IER
Access Type:
Write-only
Offset:
0x14
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
UNDES
TXEMPTY
NSSR
7
6
5
4
3
2
1
0
-
-
-
-
OVRES
MODF
TDRE
RDRF
Writing a zero to a bit in this register has no effect.
Writing a one to a bit in this register will set the corresponding bit in IMR.
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21.8.7
Name:
Interrupt Disable Register
IDR
Access Type:
Write-only
Offset:
0x18
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
UNDES
TXEMPTY
NSSR
7
6
5
4
3
2
1
0
-
-
-
-
OVRES
MODF
TDRE
RDRF
Writing a zero to a bit in this register has no effect.
Writing a one to a bit in this register will clear the corresponding bit in IMR.
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21.8.8
Name:
Interrupt Mask Register
IMR
Access Type:
Read-only
Offset:
0x1C
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
UNDES
TXEMPTY
NSSR
7
6
5
4
3
2
1
0
-
-
-
-
OVRES
MODF
TDRE
RDRF
0: The corresponding interrupt is disabled.
1: The corresponding interrupt is enabled.
A bit in this register is cleared when the corresponding bit in IDR is written to one.
A bit in this register is set when the corresponding bit in IER is written to one.
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21.8.9
Name:
Chip Select Register 0
CSR0
Access Type:
Read/Write
Offset:
0x30
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
CSAAT
CSNAAT
NCPHA
CPOL
DLYBCT
23
22
21
20
DLYBS
15
14
13
12
SCBR
7
6
5
BITS
4
• DLYBCT: Delay Between Consecutive Transfers
This field defines the delay between two consecutive transfers with the same peripheral without removing the chip select. The
delay is always inserted after each transfer and before removing the chip select if needed.
When DLYBCT equals zero, no delay between consecutive transfers is inserted and the clock keeps its duty cycle over the
character transfers.
Otherwise, the following equation determines the delay:
32 × DLYBCT
Delay Between Consecutive Transfers = -----------------------------------CLKSPI
• DLYBS: Delay Before SPCK
This field defines the delay from NPCS valid to the first valid SPCK transition.
When DLYBS equals zero, the NPCS valid to SPCK transition is 1/2 the SPCK clock period.
Otherwise, the following equations determine the delay:
DLYBSDelay Before SPCK = -------------------CLKSPI
• SCBR: Serial Clock Baud Rate
In Master Mode, the SPI Interface uses a modulus counter to derive the SPCK baud rate from the CLK_SPI. The Baud rate is
selected by writing a value from 1 to 255 in the SCBR field. The following equations determine the SPCK baud rate:
CLKSPI
SPCK Baudrate = --------------------SCBR
Writing the SCBR field to zero is forbidden. Triggering a transfer while SCBR is zero can lead to unpredictable results.
At reset, SCBR is zero and the user has to write it to a valid value before performing the first transfer.
If a clock divider (SCBRn) field is set to one and the other SCBR fields differ from one, access on CSn is correct but no correct
access will be possible on other CS.
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• BITS: Bits Per Transfer
The BITS field determines the number of data bits transferred. Reserved values should not be used.
BITS
Bits Per Transfer
0000
8
0001
9
0010
10
0011
11
0100
12
0101
13
0110
14
0111
15
1000
16
1001
4
1010
5
1011
6
1100
7
1101
Reserved
1110
Reserved
1111
Reserved
• CSAAT: Chip Select Active After Transfer
1: The Peripheral Chip Select does not rise after the last transfer is achieved. It remains active until a new transfer is requested
on a different chip select.
0: The Peripheral Chip Select Line rises as soon as the last transfer is achieved.
• CSNAAT: Chip Select Not Active After Transfer (Ignored if CSAAT = 1)
0: The Peripheral Chip Select does not rise between two transfers if the TDR is reloaded before the end of the first transfer and
if the two transfers occur on the same Chip Select.
1: The Peripheral Chip Select rises systematically between each transfer performed on the same slave for a minimal duration of:
DLYBCS
----------------------- (if DLYBCT field is different from 0)
CLKSPI
DLYBCS
+ 1- (if DLYBCT field equals 0)
-------------------------------CLKSPI
• NCPHA: Clock Phase
1: Data is captured after the leading (inactive-to-active) edge of SPCK and changed on the trailing (active-to-inactive) edge of
SPCK.
0: Data is changed on the leading (inactive-to-active) edge of SPCK and captured after the trailing (active-to-inactive) edge of
SPCK.
NCPHA determines which edge of SPCK causes data to change and which edge causes data to be captured. NCPHA is used
with CPOL to produce the required clock/data relationship between master and slave devices.
• CPOL: Clock Polarity
1: The inactive state value of SPCK is logic level one.
0: The inactive state value of SPCK is logic level zero.
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CPOL is used to determine the inactive state value of the serial clock (SPCK). It is used with NCPHA to produce the required
clock/data relationship between master and slave devices.
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21.8.10
Name:
Chip Select Register 1
CSR1
Access Type:
Read/Write
Offset:
0x34
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
CSAAT
CSNAAT
NCPHA
CPOL
DLYBCT
23
22
21
20
DLYBS
15
14
13
12
SCBR
7
6
5
BITS
4
• DLYBCT: Delay Between Consecutive Transfers
This field defines the delay between two consecutive transfers with the same peripheral without removing the chip select. The
delay is always inserted after each transfer and before removing the chip select if needed.
When DLYBCT equals zero, no delay between consecutive transfers is inserted and the clock keeps its duty cycle over the
character transfers.
Otherwise, the following equation determines the delay:
32 × DLYBCT
Delay Between Consecutive Transfers = -----------------------------------CLKSPI
• DLYBS: Delay Before SPCK
This field defines the delay from NPCS valid to the first valid SPCK transition.
When DLYBS equals zero, the NPCS valid to SPCK transition is 1/2 the SPCK clock period.
Otherwise, the following equations determine the delay:
DLYBSDelay Before SPCK = -------------------CLKSPI
• SCBR: Serial Clock Baud Rate
In Master Mode, the SPI Interface uses a modulus counter to derive the SPCK baud rate from the CLK_SPI. The Baud rate is
selected by writing a value from 1 to 255 in the SCBR field. The following equations determine the SPCK baud rate:
CLKSPI
SPCK Baudrate = --------------------SCBR
Writing the SCBR field to zero is forbidden. Triggering a transfer while SCBR is zero can lead to unpredictable results.
At reset, SCBR is zero and the user has to write it to a valid value before performing the first transfer.
If a clock divider (SCBRn) field is set to one and the other SCBR fields differ from one, access on CSn is correct but no correct
access will be possible on other CS.
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• BITS: Bits Per Transfer
The BITS field determines the number of data bits transferred. Reserved values should not be used.
BITS
Bits Per Transfer
0000
8
0001
9
0010
10
0011
11
0100
12
0101
13
0110
14
0111
15
1000
16
1001
4
1010
5
1011
6
1100
7
1101
Reserved
1110
Reserved
1111
Reserved
• CSAAT: Chip Select Active After Transfer
1: The Peripheral Chip Select does not rise after the last transfer is achieved. It remains active until a new transfer is requested
on a different chip select.
0: The Peripheral Chip Select Line rises as soon as the last transfer is achieved.
• CSNAAT: Chip Select Not Active After Transfer (Ignored if CSAAT = 1)
0: The Peripheral Chip Select does not rise between two transfers if the TDR is reloaded before the end of the first transfer and
if the two transfers occur on the same Chip Select.
1: The Peripheral Chip Select rises systematically between each transfer performed on the same slave for a minimal duration of:
DLYBCS
----------------------- (if DLYBCT field is different from 0)
CLKSPI
DLYBCS
+ 1- (if DLYBCT field equals 0)
-------------------------------CLKSPI
• NCPHA: Clock Phase
1: Data is captured after the leading (inactive-to-active) edge of SPCK and changed on the trailing (active-to-inactive) edge of
SPCK.
0: Data is changed on the leading (inactive-to-active) edge of SPCK and captured after the trailing (active-to-inactive) edge of
SPCK.
NCPHA determines which edge of SPCK causes data to change and which edge causes data to be captured. NCPHA is used
with CPOL to produce the required clock/data relationship between master and slave devices.
• CPOL: Clock Polarity
1: The inactive state value of SPCK is logic level one.
0: The inactive state value of SPCK is logic level zero.
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CPOL is used to determine the inactive state value of the serial clock (SPCK). It is used with NCPHA to produce the required
clock/data relationship between master and slave devices.
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21.8.11
Name:
Chip Select Register 2
CSR2
Access Type:
Read/Write
Offset:
0x38
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
CSAAT
CSNAAT
NCPHA
CPOL
DLYBCT
23
22
21
20
DLYBS
15
14
13
12
SCBR
7
6
5
BITS
4
• DLYBCT: Delay Between Consecutive Transfers
This field defines the delay between two consecutive transfers with the same peripheral without removing the chip select. The
delay is always inserted after each transfer and before removing the chip select if needed.
When DLYBCT equals zero, no delay between consecutive transfers is inserted and the clock keeps its duty cycle over the
character transfers.
Otherwise, the following equation determines the delay:
32 × DLYBCT
Delay Between Consecutive Transfers = -----------------------------------CLKSPI
• DLYBS: Delay Before SPCK
This field defines the delay from NPCS valid to the first valid SPCK transition.
When DLYBS equals zero, the NPCS valid to SPCK transition is 1/2 the SPCK clock period.
Otherwise, the following equations determine the delay:
DLYBSDelay Before SPCK = -------------------CLKSPI
• SCBR: Serial Clock Baud Rate
In Master Mode, the SPI Interface uses a modulus counter to derive the SPCK baud rate from the CLK_SPI. The Baud rate is
selected by writing a value from 1 to 255 in the SCBR field. The following equations determine the SPCK baud rate:
CLKSPI
SPCK Baudrate = --------------------SCBR
Writing the SCBR field to zero is forbidden. Triggering a transfer while SCBR is zero can lead to unpredictable results.
At reset, SCBR is zero and the user has to write it to a valid value before performing the first transfer.
If a clock divider (SCBRn) field is set to one and the other SCBR fields differ from one, access on CSn is correct but no correct
access will be possible on other CS.
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• BITS: Bits Per Transfer
The BITS field determines the number of data bits transferred. Reserved values should not be used.
BITS
Bits Per Transfer
0000
8
0001
9
0010
10
0011
11
0100
12
0101
13
0110
14
0111
15
1000
16
1001
4
1010
5
1011
6
1100
7
1101
Reserved
1110
Reserved
1111
Reserved
• CSAAT: Chip Select Active After Transfer
1: The Peripheral Chip Select does not rise after the last transfer is achieved. It remains active until a new transfer is requested
on a different chip select.
0: The Peripheral Chip Select Line rises as soon as the last transfer is achieved.
• CSNAAT: Chip Select Not Active After Transfer (Ignored if CSAAT = 1)
0: The Peripheral Chip Select does not rise between two transfers if the TDR is reloaded before the end of the first transfer and
if the two transfers occur on the same Chip Select.
1: The Peripheral Chip Select rises systematically between each transfer performed on the same slave for a minimal duration of:
DLYBCS
----------------------- (if DLYBCT field is different from 0)
CLKSPI
DLYBCS
+ 1- (if DLYBCT field equals 0)
-------------------------------CLKSPI
• NCPHA: Clock Phase
1: Data is captured after the leading (inactive-to-active) edge of SPCK and changed on the trailing (active-to-inactive) edge of
SPCK.
0: Data is changed on the leading (inactive-to-active) edge of SPCK and captured after the trailing (active-to-inactive) edge of
SPCK.
NCPHA determines which edge of SPCK causes data to change and which edge causes data to be captured. NCPHA is used
with CPOL to produce the required clock/data relationship between master and slave devices.
• CPOL: Clock Polarity
1: The inactive state value of SPCK is logic level one.
0: The inactive state value of SPCK is logic level zero.
431
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CPOL is used to determine the inactive state value of the serial clock (SPCK). It is used with NCPHA to produce the required
clock/data relationship between master and slave devices.
432
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21.8.12
Name:
Chip Select Register 3
CSR3
Access Type:
Read/Write
Offset:
0x3C
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
CSAAT
CSNAAT
NCPHA
CPOL
DLYBCT
23
22
21
20
DLYBS
15
14
13
12
SCBR
7
6
5
BITS
4
• DLYBCT: Delay Between Consecutive Transfers
This field defines the delay between two consecutive transfers with the same peripheral without removing the chip select. The
delay is always inserted after each transfer and before removing the chip select if needed.
When DLYBCT equals zero, no delay between consecutive transfers is inserted and the clock keeps its duty cycle over the
character transfers.
Otherwise, the following equation determines the delay:
32 × DLYBCT
Delay Between Consecutive Transfers = -----------------------------------CLKSPI
• DLYBS: Delay Before SPCK
This field defines the delay from NPCS valid to the first valid SPCK transition.
When DLYBS equals zero, the NPCS valid to SPCK transition is 1/2 the SPCK clock period.
Otherwise, the following equations determine the delay:
DLYBSDelay Before SPCK = -------------------CLKSPI
• SCBR: Serial Clock Baud Rate
In Master Mode, the SPI Interface uses a modulus counter to derive the SPCK baud rate from the CLK_SPI. The Baud rate is
selected by writing a value from 1 to 255 in the SCBR field. The following equations determine the SPCK baud rate:
CLKSPI
SPCK Baudrate = --------------------SCBR
Writing the SCBR field to zero is forbidden. Triggering a transfer while SCBR is zero can lead to unpredictable results.
At reset, SCBR is zero and the user has to write it to a valid value before performing the first transfer.
If a clock divider (SCBRn) field is set to one and the other SCBR fields differ from one, access on CSn is correct but no correct
access will be possible on other CS.
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• BITS: Bits Per Transfer
The BITS field determines the number of data bits transferred. Reserved values should not be used.
BITS
Bits Per Transfer
0000
8
0001
9
0010
10
0011
11
0100
12
0101
13
0110
14
0111
15
1000
16
1001
4
1010
5
1011
6
1100
7
1101
Reserved
1110
Reserved
1111
Reserved
• CSAAT: Chip Select Active After Transfer
1: The Peripheral Chip Select does not rise after the last transfer is achieved. It remains active until a new transfer is requested
on a different chip select.
0: The Peripheral Chip Select Line rises as soon as the last transfer is achieved.
• CSNAAT: Chip Select Not Active After Transfer (Ignored if CSAAT = 1)
0: The Peripheral Chip Select does not rise between two transfers if the TDR is reloaded before the end of the first transfer and
if the two transfers occur on the same Chip Select.
1: The Peripheral Chip Select rises systematically between each transfer performed on the same slave for a minimal duration of:
DLYBCS
----------------------- (if DLYBCT field is different from 0)
CLKSPI
DLYBCS
+ 1- (if DLYBCT field equals 0)
-------------------------------CLKSPI
• NCPHA: Clock Phase
1: Data is captured after the leading (inactive-to-active) edge of SPCK and changed on the trailing (active-to-inactive) edge of
SPCK.
0: Data is changed on the leading (inactive-to-active) edge of SPCK and captured after the trailing (active-to-inactive) edge of
SPCK.
NCPHA determines which edge of SPCK causes data to change and which edge causes data to be captured. NCPHA is used
with CPOL to produce the required clock/data relationship between master and slave devices.
• CPOL: Clock Polarity
1: The inactive state value of SPCK is logic level one.
0: The inactive state value of SPCK is logic level zero.
434
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CPOL is used to determine the inactive state value of the serial clock (SPCK). It is used with NCPHA to produce the required
clock/data relationship between master and slave devices.
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21.8.13 Write Protection Control Register
Register Name:
WPCR
Access Type:
Read-write
Offset:
0xE4
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
18
17
16
10
9
8
SPIWPKEY[23:16]
23
22
21
20
19
SPIWPKEY[15:8]
15
14
13
12
11
SPIWPKEY[7:0]
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
SPIWPEN
• SPIWPKEY: SPI Write Protection Key Password
If a value is written in SPIWPEN, the value is taken into account only if SPIWPKEY is written with “SPI” (SPI written in ASCII
Code, i.e. 0x535049 in hexadecimal).
• SPIWPEN: SPI Write Protection Enable
1: The Write Protection is Enabled
0: The Write Protection is Disabled
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21.8.14 Write Protection Status Register
Register Name:
WPSR
Access Type:
Read-only
Offset:
0xE8
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
2
1
0
SPIWPVSRC
7
6
5
4
3
-
-
-
-
-
SPIWPVS
• SPIWPVSRC: SPI Write Protection Violation Source
This Field indicates the Peripheral Bus Offset of the register concerned by the violation (MR or CSRx)
• SPIWPVS: SPI Write Protection Violation Status
SPIWPVS value
Violation Type
1
The Write Protection has blocked a Write access to a protected register (since the last read).
2
Software Reset has been performed while Write Protection was enabled (since the last read
or since the last write access on MR, IER, IDR or CSRx).
3
Both Write Protection violation and software reset with Write Protection enabled have
occurred since the last read.
4
Write accesses have been detected on MR (while a chip select was active) or on CSRi (while
the Chip Select “i” was active) since the last read.
5
The Write Protection has blocked a Write access to a protected register and write accesses
have been detected on MR (while a chip select was active) or on CSRi (while the Chip Select
“i” was active) since the last read.
6
Software Reset has been performed while Write Protection was enabled (since the last read
or since the last write access on MR, IER, IDR or CSRx) and some write accesses have been
detected on MR (while a chip select was active) or on CSRi (while the Chip Select “i” was
active) since the last read.
7
- The Write Protection has blocked a Write access to a protected register.
and
- Software Reset has been performed while Write Protection was enabled.
and
- Write accesses have been detected on MR (while a chip select was active) or on CSRi
(while the Chip Select “i” was active) since the last read.
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21.8.15
Version Register
Register Name:
VERSION
Access Type:
Read-only
Offset:
0xFC
Reset Value:
–
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
15
14
13
12
9
8
VARIANT
11
10
VERSION[11:8]
7
6
5
4
3
2
1
0
VERSION[7:0]
• VARIANT
Reserved. No functionality associated.
• VERSION
Version number of the module. No functionality associated.
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21.9
Module Configuration
The specific configuration for each SPI instance is listed in the following tables.The module bus
clocks listed here are connected to the system bus clocks. Please refer to the Power Manager
section for details.
Table 21-4.
Module Clock Name
Module Name
Clock Name
SPI0
CLK_SPI0
SPI1
CLK_SPI1
Table 21-5.
Register Reset Values
Register
Reset Value
VERSION
0x00000200
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22. Two-Wire Slave Interface (TWIS)
Rev 1.0.0.1
22.1
Features
• Compatible with I²C standard
•
•
•
•
•
•
22.2
– 100 and 400 kbit/s transfer speeds
– 7 and 10-bit and General Call addressing
Compatible with SMBus standard
– Hardware Packet Error Checking (CRC) generation and verification with ACK response
– SMBALERT interface
– 25 ms clock low timeout delay
– 25 ms slave cumulative clock low extend time
Compatible with PMBus
DMA interface for reducing CPU load
Arbitrary transfer lengths, including 0 data bytes
Optional clock stretching if transmit or receive buffers not ready for data transfer
32-bit Peripheral Bus interface for configuration of the interface
Overview
The Atmel Two-wire Interface Slave (TWIS) interconnects components on a unique two-wire
bus, made up of one clock line and one data line with speeds of up to 400 kbit/s, based on a
byte-oriented transfer format. It can be used with any Atmel Two-wire Interface bus I²C or
SMBus compatible master. TWIS is always a bus slave and can transfer sequential or single
bytes.
Below, Table 22-1 on page 440 lists the compatibility level of the Atmel Two-wire Slave Interface
and a full I²C compatible device.
Table 22-1.
Atmel TWIS Compatibility with I²C Standard
I²C Standard
Atmel TWIS
Standard Mode Speed (100 KHz)
Supported
Fast Mode Speed (400 KHz)
Supported
7 or 10 bits Slave Addressing
Supported
START BYTE(1)
Not Supported
Repeated Start (Sr) Condition
Supported
ACK and NAK Management
Supported
Slope control and input filtering (Fast mode)
Supported
Clock stretching
Supported
Note:
1. START + b000000001 + Ack + Sr
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Below, Table 22-2 on page 441 lists the compatibility level of the Atmel Two-wire Slave Interface
and a full SMBus compatible device.
Table 22-2.
22.3
SMBus Standard
Atmel TWIS
Bus Timeouts
Supported
Address Resolution Protocol
Supported
Alert
Supported
Packet Error Checking
Supported
List of Abbreviations
Table 22-3.
22.4
Atmel TWIS Compatibility with SMBus Standard
Abbreviations
Abbreviation
Description
TWI
Two-wire Interface
A
Acknowledge
NA
Non Acknowledge
P
Stop
S
Start
Sr
Repeated Start
SADR
Slave Address
ADR
Any address except SADR
R
Read
W
Write
Block Diagram
Figure 22-1. Block Diagram
Peripheral
Bus Bridge
TWCK
I/O controller
Two-wire
Interface
Power
Manager
TWD
TWALM
Interrupt
Controller
CLK_TWIS
TWI Interrupt
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22.5
Application Block Diagram
Figure 22-2. Application Block Diagram
VDD
Rp
Host with
TWI
Interface
Rp
TWD
TWCK
Atmel TWI
serial EEPROM
Slave 1
I²C RTC
I²C LCD
controller
I²C temp.
sensor
Slave 2
Slave 3
Slave 4
Rp: Pull up value as given by the I²C Standard
22.6
I/O Lines Description
Table 22-4.
I/O Lines Description
Pin Name
Pin Description
TWD
Two-wire Serial Data
Input/Output
TWCK
Two-wire Serial Clock
Input/Output
TWALM
SMBus SMBALERT
Input/Output
22.7
Type
Product Dependencies
In order to use this module, other parts of the system must be configured correctly, as described
below.
22.7.1
I/O Lines
Both TWD and TWCK are bidirectional lines, connected to a positive supply voltage via a current
source or pull-up resistor (see Figure 22-2 on page 442). When the bus is free, both lines are
high. The output stages of devices connected to the bus must have an open-drain or open-collector to perform the wired-AND function.
TWALM is used to implement the optional SMBus SMBALERT signal.
TWALM, TWD, and TWCK pins may be multiplexed with I/O Controller lines. To enable the
TWIS, the programmer must perform the following steps:
• Program the I/O Controller to:
– Dedicate TWD, TWCK and optionally TWALM as peripheral lines.
– Define TWD, TWCK and optionally TWALM as open-drain.
22.7.2
Power Management
If the CPU enters a sleep mode that disables clocks used by the TWIS, the TWIS will stop functioning and resume operation after the system wakes up from sleep mode.
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22.7.3
Clocks
The clock for the TWIS bus interface (CLK_TWIS) is generated by the Power Manager. This
clock is enabled at reset, and can be disabled in the Power Manager. It is recommended to disable the TWIS before disabling the clock, to avoid freezing the TWIS in an undefined state.
22.7.4
Interrupts
The TWIS interrupt request lines are connected to the interrupt controller. Using the TWIS interrupts requires the interrupt controller to be programmed first.
22.7.5
22.8
22.8.1
Debug Operation
When an external debugger forces the CPU into debug mode, the TWIS continues normal operation. If the TWIS is configured in a way that requires it to be periodically serviced by the CPU
through interrupts or similar, improper operation or data loss may result during debugging.
Functional Description
Transfer Format
The data put on the TWD line must be 8 bits long. Data is transferred MSB first; each byte must
be followed by an acknowledgement. The number of bytes per transfer is unlimited (see Figure
22-4 on page 443).
Each transfer begins with a START condition and terminates with a STOP condition (see Figure
22-3 on page 443).
• A high-to-low transition on the TWD line while TWCK is high defines the START condition.
• A low-to-high transition on the TWD line while TWCK is high defines a STOP condition.
Figure 22-3.
START and STOP Conditions
TWD
TWCK
Start
Stop
Figure 22-4. Transfer Format
TWD
TWCK
Start
22.8.2
Address
R/W
Ack
Data
Ack
Data
Ack
Stop
Operation
TWIS has two modes of operation:
• Slave transmitter mode
• Slave receiver mode
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A master is a device which starts and stops a transfer and generates the TWCK clock. A slave is
assigned an address and responds to requests from the master. These modes are described in
the following chapters.
Figure 22-5. Typical Application Block Diagram
VDD
Rp
Host with
TWI
Interface
Rp
TWD
TWCK
Atmel TWI
Serial EEPROM
Slave 1
I²C RTC
I²C LCD
Controller
I²C Temp.
Sensor
Slave 2
Slave 3
Slave 4
Rp: Pull up value as given by the I²C Standard
22.8.2.1
Bus Timing
The Timing Register (TR) is used to control the timing of bus signals driven by TWIS. TR
describes bus timings as a function of cycles of the prescaled CLK_TWIS. The clock prescaling
can be selected through TR.EXP.
f CLK – TWIS
f prescaled = -------------------------( EXP + 1 ) )
2
TR has the following fields:
TLOWS: Prescaled clock cycles used to time SMBUS timeout TLOW:SEXT.
TTOUT: Prescaled clock cycles used to time SMBUS timeout TTIMEOUT.
SUDAT: Non-prescaled clock cycles for data setup and hold count. Used to time TSU_DAT.
EXP: Specifies the clock prescaler setting used for the SMBUS timeouts.
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Figure 22-6. Bus Timing Diagram
t HIGH
t LOW
S
t
HD:STA
t LOW
t
SU:DAT
t
HD:DAT
t
t
22.8.2.2
t
SU:DAT
SU:STA
SU:STO
P
Sr
Setting Up and Performing a Transfer
Operation of TWIS is mainly controlled by the Control Register (CR). The following list presents
the main steps in a typical communication:
1. Before any transfers can be performed, bus timings must be configured by programming the Timing Register (TR).
2. If a DMA controller is to be used for the transfers, it must be set up.
3. The Control Register (CR) must be configured with information such as the slave
address, SMBus mode, Packet Error Checking (PEC), number of bytes to transfer, and
which addresses to match.
The interrupt system can be set up to give interrupt request on specific events or error conditions, for example when a byte has been received.
The NBYTES register is only used in SMBus mode, when PEC is enabled. In I²C mode or in
SMBus mode when PEC is disabled, the NBYTES register is not used, and should be written to
0. NBYTES is updated by hardware, so in order to avoid hazards, software updates of NBYTES
can only be done through writes to the NBYTES register.
22.8.2.3
Address Matching
TWIS can be set up to match several different addresses. More than one address match may be
enabled simultaneously, allowing TWIS to be assigned to several addresses. The address
matching phase is initiated after a START or REPEATED START condition. When TWIS
receives an address that generates an address match, an ACK is automatically returned to the
master.
In I²C mode:
• The address in CR.ADR is checked for address match if CR.SMATCH is set.
• The General Call address is checked for address match if CR.GCMATCH is set.
In SMBus mode:
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• The address in CR.ADR is checked for address match if CR.SMATCH is set.
• The Alert Response Address is checked for address match if CR.SMAL is set.
• The Default Address is checked for address match if CR.SMDA is set.
• The Host Header Address is checked for address match if CR.SMHH is set.
22.8.2.4
Clock Stretching
Any slave or bus master taking part in a transfer may extend the TWCK low period at any time.
TWIS may extend the TWCK low period after each byte transfer if CR.STREN=1 and:
• Module is in slave transmitter mode, data should be transmitted, but THR is empty, or
• Module is in slave receiver mode, a byte has been received and placed into the internal
shifter, but RHR is full, or
• Stretch-on-address-match bit CR.SOAM=1 and slave was addressed. Bus clock remains
stretched until all address match bits in SR have been cleared.
If CR.STREN=0 and:
• Module is in slave transmitter mode, data should be transmitted but THR is empty: Transmit
the value present in THR (the last transmitted byte or reset value), and set SR.URUN.
• Module is in slave receiver mode, a byte has been received and placed into the internal
shifter, but RHR is full: Discard the received byte and set SR.ORUN.
22.8.2.5
Bus Errors
If a bus error (misplaced START or STOP) condition is detected, the SR.BUSERR bit is set and
TWIS waits for a new START condition.
22.8.3
Slave Transmitter Mode
If TWIS matches an address in which the R/W bit in the TWI address phase transfer is set, it will
enter slave transmitter mode and set SR.TRA
After the address phase, the following is done:
1. If SMBus mode and PEC is used, NBYTES must be set up with the number of bytes to
transmit. This is necessary in order to know when to transmit PEC byte. NBYTES can
also be used to count the number of bytes received if using DMA.
2. Byte to transmit depends on I²C/SMBus mode and CR.PEC:
– If in I²C mode or CR.PEC=0 or NBYTES!=0: TWIS waits until THR contains a valid
data byte, possibly stretching low period of TWCK. SR.TXRDY indicates the state of
THR.
– SMBus mode and CR.PEC=1: If NBYTES=0, the generated PEC byte is
automatically transmitted instead of a data byte from THR. TWCK will not be
stretched by TWIS.
3. Transmit the correct data byte. Set SR.BTF when done.
4. Update NBYTES. If CR.CUP is set, NBYTES is incremented, otherwise NBYTES is
decremented.
5. After each data byte has been transferred, the master transmits an ACK or NAK bit. If a
NAK bit is received, transfer is finished, and TWIS will wait for a STOP or REPEATED
START. If an ACK bit is received, more data should be transmitted, jump to step 2.
6. If STOP is received, SR.TCOMP and SR.STO will be set.
7. If REPEATED START is received, SR.REP will be set.
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The TWI transfers require the receiver to acknowledge each received data byte. During the
acknowledge clock pulse (9th pulse), the slave releases the data line (HIGH), enabling the master to pull it down in order to generate the acknowledge. The slave polls the data line during this
clock pulse and sets the Not Acknowledge bit (NAK) in the Status Register if the master does
not acknowledge the data byte. A NAK means that the master does not wish to receive additional data bytes. As with the other status bits, an interrupt can be generated if enabled in the
Interrupt Enable Register (IER).
TXRDY is used as Transmit Ready for the Peripheral DMA Controller transmit channel.
The end of the complete transfer is marked by the SR.TCOMP bit set to one. See Figure 22-7 on
page 447 and Figure 22-8 on page 447.
Figure 22-7. Slave Transmitter with One Data Byte
TWD
S
DADR
W
A
DATA
A
P
TCOMP
TXRDY
STOP sent by master
Write THR (DATA)
NBYTES set to 1
Figure 22-8. Slave Transmitter with Multiple Data Bytes
TWD
S
DADR
W
A
DATA n
A
DATA n+5
A
DATA n+m
A
P
TCOMP
TXRDY
Write THR (Data n)
NBYTES set to m
22.8.4
Write THR (Data n+1)
Write THR (Data n+m)
Last data sent
STOP sent by master
Slave Receiver Mode
If TWIS matches an address in which the R/W bit in the TWI address phase transfer is cleared, it
will enter slave receiver mode and clear SR.TRA.
After the address phase, the following is repeated:
1. If SMBus mode and PEC is used, NBYTES must be set up with the number of bytes to
receive. This is necessary in order to know which of the received bytes is the PEC byte.
NBYTES can also be used to count the number of bytes received if using DMA.
2. Receive a byte. Set SR.BTF when done.
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3. Update NBYTES. If CR.CUP is written to one, NBYTES is incremented, otherwise
NBYTES is decremented. NBYTES is usually configured to count downwards if PEC is
used.
4. After a data byte has been received, the slave transmits an ACK or NAK bit. For ordinary data bytes, the CR.ACK field controls if an ACK or NAK should be returned. If PEC
is enabled and the last byte received was a PEC byte (indicated by NBYTES=0), TWIS
will automatically return an ACK if the PEC value was correct, otherwise a NAK will be
returned.
5. If STOP is received, SR.TCOMP will be set.
6. If REPEATED START is received, SR.REP will be set.
The TWI transfers require the receiver to acknowledge each received data byte. During the
acknowledge clock pulse (9th pulse), the master releases the data line (HIGH), enabling the
slave to pull it down in order to generate the acknowledge. The master polls the data line during
this clock pulse.
RXRDY is used as Receive Ready for the Peripheral DMA Controller receive channel.
Figure 22-9. Slave Receiver with One Data Byte
TWD
S
DADR
R
A
DATA
N
P
TCOMP
RXRDY
Read RHR
Figure 22-10. Slave Receiver with Multiple Data Bytes
TWD
S
DADR
R
A
DATA n
A
DATA (n+1)
A
DAT A (n+m)-1
A
DATA (n+m)
N
P
TCOMP
RXRDY
Read RHR
DATA n
22.8.5
Read RHR
DATA (n+1)
Read RHR
DAT A (n+m)-1
Read RHR
DATA (n+m)
Using the Peripheral DMA Controller
The use of the Peripheral DMA Controller significantly reduces the CPU load. The programmer
can set up ring buffers for the DMA controller, containing data to transmit or free buffer space to
place received data. By initializing NBYTES to 0 before a transfer, and setting CR.CUP,
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NBYTES is incremented by 1 each time a data has been transmitted or received. This allows the
programmer to detect how much data was actually transferred by the DMA system.
To assure correct behavior, respect the following programming sequences:
22.8.5.1
Data Transmit with the Peripheral DMA Controller
1. Initialize the transmit Peripheral DMA Controller (memory pointers, size, etc.).
2. Configure the TWIS (ADR, NBYTES, etc.).
3. Start the transfer by setting the Peripheral DMA Controller TXTEN bit.
4. Wait for the Peripheral DMA Controller end TX flag.
5. Disable the Peripheral DMA Controller by setting the Peripheral DMA Controller TXDIS
bit.
22.8.5.2
Data Receive with the Peripheral DMA Controller
1. Initialize the receive Peripheral DMA Controller (memory pointers, size - 1, etc.).
2. Configure the TWIS (ADR, NBYTES, etc.).
3. Start the transfer by setting the Peripheral DMA Controller RXTEN bit.
4. Wait for the Peripheral DMA Controller end RX flag.
5. Disable the Peripheral DMA Controller by setting the Peripheral DMA Controller RXDIS
bit.
22.8.6
SMBus Mode
SMBus mode is enabled when CR.SMEN is written to one. SMBus mode operation is similar to
I²C operation with the following exceptions:
• Only 7-bit addressing can be used.
• The SMBus standard describes a set of timeout values to ensure progress and throughput on
the bus. These timeout values must be programmed into TR.
• Transmissions can optionally include a CRC byte, called Packet Error Check (PEC).
• A dedicated bus line, SMBALERT, allows a slave to get a master’s attention.
• A set of addresses have been reserved for protocol handling, such as Alert Response
Address (ARA) and Host Header (HH) Address. Address matching on these addresses can
be enabled by configuring CR appropriately.
22.8.6.1
Packet Error Checking
Each SMBus transfer can optionally end with a CRC byte, called the PEC byte. Writing a one to
CR.PECEN enables automatic PEC handling in the current transfer. The PEC generator is
always updated on every bit transmitted or received, so that PEC handling on following linked
transfers will be correct.
In slave receiver mode, the master calculates a PEC value and transmits it to the slave after all
data bytes have been transmitted. Upon reception of this PEC byte, the slave will compare it to
the PEC value it has computed itself. If the values match, the data was received correctly, and
the slave will return an ACK to the master. If the PEC values differ, data was corrupted, and the
slave will return a NAK value. The SR.SMBPECERR bit is set automatically if a PEC error
occurred.
In slave transmitter mode, the slave calculates a PEC value and transmits it to the master after
all data bytes have been transmitted. Upon reception of this PEC byte, the master will compare
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it to the PEC value it has computed itself. If the values match, the data was received correctly. If
the PEC values differ, data was corrupted, and the master must take appropriate action.
The PEC byte is automatically inserted in a slave transmitter transmission if PEC enabled when
NBYTES reaches zero. The PEC byte is identified in a slave receiver transmission if PEC
enabled when NBYTES reaches zero. NBYTES must therefore be set to the total number of
data bytes in the transmission, including the PEC byte.
22.8.6.2
Timeouts
The Timing Register (TR) configures the SMBus timeout values. If a timeout occurs, the slave
will leave the bus. The SR.SMBTOUT bit is also set.
22.8.6.3
SMBALERT
A slave can get the master’s attention by pulling the SMBALERT line low. This is done by setting
the CR.SMBAL bit. This will also enable address match on the Alert Response Address (ARA).
22.8.7
Identifying Bus Events
This chapter lists the different bus events, and how these affects bits in the TWIS registers. This
is intended to help writing drivers for the TWIS.
Table 22-5.
Bus Events
Event
Effect
Slave transmitter has sent a
data byte
SR.THR is cleared.
SR.BTF is set.
The value of the ACK bit sent immediately after the data byte is given
by CR.ACK.
Slave receiver has received
a data byte
SR.RHR is set.
SR.BTF is set.
SR.NAK updated according to value of ACK bit received from master.
Start+Sadr on bus, but
address is to another slave
None.
Start+Sadr on bus, current
slave is addressed, but
address match enable bit in
CR is not set
None.
Start+Sadr on bus, current
slave is addressed,
corresponding address
match enable bit in CR set
Correct address match bit in SR is set.
SR.TRA updated according to transfer direction.
Slave enters appropriate transfer direction mode and data transfer
can commence.
Start+Sadr on bus, current
slave is addressed,
corresponding address
match enable bit in CR set,
SR.STREN and SR.SOAM
are set.
Correct address match bit in SR is set.
SR.TRA updated according to transfer direction.
Slave stretches TWCK immediately after transmitting the address
ACK bit. TWCK remains stretched until all address match bits in SR
have been cleared.
Slave the enters appropriate transfer direction mode and data transfer
can commence.
Repeated Start received
after being addressed
SR.REP set.
SR.TCOMP unchanged.
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Table 22-5.
Bus Events
Event
Effect
Stop received after being
addressed
SR.STO set.
SR.TCOMP set.
Start, Repeated Start or
Stop received in illegal
position on bus
SR.BUSERR set.
Data is to be received in
slave receiver mode,
SR.STREN is set, and RHR
is full
TWCK is stretched until RHR has been read.
Data is to be transmitted in
slave receiver mode,
SR.STREN is set, and THR
is empty
TWCK is stretched until THR has been written.
Data is to be received in
slave receiver mode,
SR.STREN is cleared, and
RHR is full
TWCK is not stretched, read data is discarded.
SR.ORUN is set.
Data is to be transmitted in
slave receiver mode,
SR.STREN is cleared, and
THR is empty
TWCK is not stretched, previous contents of THR is written to bus.
SR.URUN is set.
SMBus timeout received
SR.SMBTOUT is set.
TWCK and TWD are immediately released.
Slave transmitter in SMBus
PEC mode has transmitted
a PEC byte, that was not
identical to the PEC
calculated by the master
receiver.
Slave receiver discovers
SMBus PEC Error
Master receiver will transmit a NAK as usual after the last byte of a
master receiver transfer.
Master receiver will retry the transfer at a later time.
SR.SMBPECERR is set.
NAK returned after the data byte.
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22.9
User Interface
Table 22-6.
TWIS Register Memory Map
Offset
Register
Register Name
Access
Reset
0x00
Control Register
CR
Read/Write
0x00000000
0x04
NBYTES Register
NBYTES
Read/Write
0x00000000
0x08
Timing Register
TR
Read/Write
0x00000000
0x0C
Receive Holding Register
RHR
Read-only
0x00000000
0x10
Transmit Holding Register
THR
Write-only
0x00000000
0x14
Packet Error Check Register
PECR
Read-only
0x00000000
0x18
Status Register
SR
Read-only
0x00000002
0x1c
Interrupt Enable Register
IER
Write-only
0x00000000
0x20
Interrupt Disable Register
IDR
Write-only
0x00000000
0x24
Interrupt Mask Register
IMR
Read-only
0x00000000
0x28
Status Clear Register
SCR
Write-only
0x00000000
0x2C
Parameter Register
PR
Read-only
(1)
0x30
Version Register
VR
Read-only
(1)
Note:
1. The reset values for these registers are device specific. Please refer to the Module Configuration section at the end of this chapter.
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22.9.1
Name:
Control Register
CR
Access Type:
Read/Write
Offset:
0x00
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
TENBIT
23
22
21
20
19
18
17
16
ADR[9:8]
ADR[7:0]
15
14
13
12
11
10
9
8
SOAM
CUP
ACK
PECEN
SMHH
SMDA
SMBALERT
7
6
5
4
3
2
1
0
SWRST
-
-
STREN
GCMATCH
SMATCH
SMEN
SEN
• TENBIT: Ten Bit Address Match
Write this bit to zero to disable Ten Bit Address Match.
Write this bit to one to enable Ten Bit Address Match.
• ADR: Slave Address
Slave address used in slave address match. Bits 9:0 are used if in 10-bit mode, bits 6:0 otherwise.
• SOAM: Stretch Clock on Address Match
Writing this bit to zero will not strech bus clock after address match.
Writing this bit to one will strech bus clock after address match.
• CUP: NBYTES Count Up
Writing this bit to zero causes NBYTES to count down (decrement) per byte transferred.
Writing this bit to one causes NBYTES to count up (increment) per byte transferred.
• ACK: Slave Receiver Data Phase ACK Value
Writing this bit to zero causes a low value to be returned in the ACK cycle of the data phase in slave receiver mode.
Writing this bit to one causes a high value to be returned in the ACK cycle of the data phase in slave receiver mode.
• PECEN: Packet Error Checking Enable
Writing this bit to zero disables SMBus PEC (CRC) generation and check.
Writing this bit to one enables SMBus PEC (CRC) generation and check.
• SMHH: SMBus Host Header
Writing this bit to zero causes TWIS not to acknowledge the SMBus Host Header.
Writing this bit to one causes TWIS to acknowledge the SMBus Host Header.
• SMDA: SMBus Default Address
Writing this bit to zero causes TWIS not to acknowledge the SMBus Default Address.
Writing this bit to one causes TWIS to acknowledge the SMBus Default Address.
• SMBALERT: SMBus Alert
Writing this bit to zero causes TWIS to release the SMBALERT line and not to acknowledge the SMBus Alert Response
Address (ARA).
Writing this bit to one causes TWIS to pull down the SMBALERT line and to acknowledge the SMBus Alert Response Address
(ARA).
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• SWRST: Software Reset
This bit will always read as 0.
Writing a zero to this bit has no effect.
Writing a one to this bit resets the TWIS.
• STREN: Clock Stretch Enable
Writing this bit to zero disables clock stretching if RHR/THR buffer full/empty. May cause over/underrun.
Writing this bit to one enables clock stretching if RHR/THR buffer full/empty.
• GCMATCH: General Call Address Match
Writing this bit to zero causes TWIS not to acknowledge the General Call Address.
Writing this bit to one causes TWIS to acknowledge the General Call Address.
• SMATCH: Slave Address Match
Writing this bit to zero causes TWIS not to acknowledge the Slave Address.
Writing this bit to one causes TWIS to acknowledge the Slave Address.
• SMEN: SMBus Mode Enable
Writing this bit to zero disables SMBus mode.
Writing this bit to one enables SMBus mode.
• SEN: Slave Enable
Writing this bit to zero disables the slave interface.
Writing this bit to one enables the slave interface.
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22.9.2
Name:
NBYTES Register
NBYTES
Access Type:
Read/Write
Offset:
0x04
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
-
23
22
21
20
-
15
14
13
12
-
7
6
5
4
NBYTES
• NBYTES: Number of Bytes to Transfer
Writing to this field updates the NBYTES counter. Can also be read to to learn the progress of the transfer. Can be incremented
or decremented automatically by hardware.
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22.9.3
Name:
Timing Register
TR
Access Type:
Read/Write
Offset:
0x08
Reset Value:
0x00000000
31
30
29
28
27
26
EXP
23
22
25
24
-
21
20
19
18
17
16
11
10
9
8
3
2
1
0
SUDAT
15
14
13
12
TTOUT
7
6
5
4
TLOWS
• EXP: Clock Prescaler
Used to specify how to prescale the SMBus TLOWS counter. The counter is prescaled according to the following formula:
f clkpb
f prescaled = ----------------------( EXP + 1 )
2
• SUDAT: Data Setup Cycles
Non-prescaled clock cycles for data setup count. Used to time TSU_DAT. Data is driven SUDAT cycles after TWCK low detected.
This timing is used for timing the ACK/NAK bits, and any data bits driven in slave transmitter mode.
• TTOUT: SMBus Ttimeout Cycles
Prescaled clock cycles used to time SMBus TTIMEOUT.
• TLOWS: SMBus Tlow:sext Cycles
Prescaled clock cycles used to time SMBus TLOW:SEXT.
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22.9.4
Name:
Receive Holding Register
RHR
Access Type:
Read-only
Offset:
0x0C
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
RXDATA
• RXDATA: Received Data Byte
When the RXRDY bit in the Status Register (SR) is set, this field contains a byte received from the TWI bus.
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22.9.5
Name:
Transmit Holding Register
THR
Access Type:
Write-only
Offset:
0x10
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
TXDATA
• TXDATA: Data Byte to Transmit
Write data to be transferred on the TWI bus here.
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22.9.6
Name:
Packet Error Check Register
PECR
Access Type:
Read-only
Offset:
0x14
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
PEC
• PEC: Calculated PEC Value
The calculated PEC value. Updated automatically by hardware after each byte has been transferred. Reset by hardware after a
STOP condition. Provided if the user manually wishes to control when the PEC byte is transmitted, or wishes to access the PEC
value for other reasons. In ordinary operation, the PEC handling is done automatically by hardware.
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22.9.7
Name:
Status Register
SR
Access Type:
Read-only
Offset:
0x18
Reset Value:
0x000000002
31
30
29
28
27
26
25
24
-
23
22
21
20
19
18
17
16
BTF
REP
STO
SMBDAM
SMBHHM
SMBALERTM
GCM
SAM
15
14
13
12
11
10
9
8
-
BUSERR
SMBPECERR
SMBTOUT
-
-
-
NAK
7
6
5
4
3
2
1
0
ORUN
URUN
TRA
-
TCOMP
SEN
TXRDY
RXRDY
• BTF: Byte Transfer Finished
This bit is set when byte transfer has completed.
This bit is cleared when the corresponding bit in SCR is written to one.
• REP: Repeated Start Received
This bit is set when REPEATED START condition received.
This bit is cleared when the corresponding bit in SCR is written to one.
• STO: Stop Received
This bit is set when STOP condition received.
This bit is cleared when the corresponding bit in SCR is written to one.
• SMBDAM: SMBus Default Address Match
This bit is set when received address matched SMBus Default Address.
This bit is cleared when the corresponding bit in SCR is written to one.
• SMBHHM: SMBus Host Header Address Match
This bit is set when received address matched SMBus Host Header Address.
This bit is cleared when the corresponding bit in SCR is written to one.
• SMBALERTM: SMBus Alert Response Address Match
This bit is set when received address matched SMBus Alert Response Address.
This bit is cleared when the corresponding bit in SCR is written to one.
• GCM: General Call Match
This bit is set when received address matched General Call Address.
This bit is cleared when the corresponding bit in SCR is written to one.
• SAM: Slave Address Match
This bit is set when received address matched Slave Address.
This bit is cleared when the corresponding bit in SCR is written to one.
• BUSERR: Bus Error
This bit is set when a misplaced start or stop condition has occurred.
This bit is cleared when the corresponding bit in SCR is written to one.
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• SMBPECERR: SMBus PEC Error
This bit is set when SMBus PEC error has occurred.
This bit is cleared when the corresponding bit in SCR is written to one.
• SMBTOUT: SMBus Timeout
This bit is set when SMBus timeout has occurred.
This bit is cleared when the corresponding bit in SCR is written to one.
• NAK: NAK Received
This bit is set when NAK was received from master during slave transmitter operation.
This bit is cleared when the corresponding bit in SCR is written to one.
• ORUN: Overrun
This bit is set when overrun has occurred in slave receiver mode. Can only occur if CR.STREN=0.
This bit is cleared when the corresponding bit in SCR is written to one.
• URUN: Underrun
This bit is set when underrun has occurred in slave transmitter mode. Can only occur if CR.STREN=0.
This bit is cleared when the corresponding bit in SCR is written to one.
• TRA: Transmitter Mode
0: The slave is in slave receiver mode.
1: The slave is in slave transmitter mode.
• TCOMP: Transmission Complete
This bit is set when transmission is complete. Set after receiving a STOP after being addressed.
This bit is cleared when the corresponding bit in SCR is written to one.
• SEN: Slave Enabled
0: The slave interface is disabled.
1: The slave interface is enabled.
• TXRDY: TX Buffer Ready
0: The TX buffer is full and should not be written to.
1: The TX buffer is empty, and can accept new data.
• RXRDY: RX Buffer Ready
0: No RX data ready in RHR.
1: RX data is ready to be read from RHR.
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22.9.8
Name:
Interrupt Enable Register
IER
Access Type:
Write-only
Offset:
0x1C
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
BTF
REP
STO
SMBDAM
SMBHHM
SMBALERTM
GCM
SAM
15
14
13
12
11
10
9
8
-
BUSERR
SMBPECERR
SMBTOUT
-
-
-
NAK
7
6
5
4
3
2
1
0
ORUN
URUN
-
-
TCOMP
-
TXRDY
RXRDY
Writing a zero to a bit in this register has no effect.
Writing a one to a bit in this register will set the corresponding bit in IMR.
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22.9.9
Name:
Interrupt Disable Register
IDR
Access Type:
Write-only
Offset:
0x20
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
BTF
REP
STO
SMBDAM
SMBHHM
SMBALERTM
GCM
SAM
15
14
13
12
11
10
9
8
-
BUSERR
SMBPECERR
SMBTOUT
-
-
-
NAK
7
6
5
4
3
2
1
0
ORUN
URUN
-
-
TCOMP
-
TXRDY
RXRDY
Writing a zero to a bit in this register has no effect.
Writing a one to a bit in this register will clear the corresponding bit in IMR.
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22.9.10
Name:
Interrupt Mask Register
IMR
Access Type:
Read-only
Offset:
0x24
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
BTF
REP
STO
SMBDAM
SMBHHM
SMBALERTM
GCM
SAM
15
14
13
12
11
10
9
8
-
BUSERR
SMBPECERR
SMBTOUT
-
-
-
NAK
7
6
5
4
3
2
1
0
ORUN
URUN
-
-
TCOMP
-
TXRDY
RXRDY
0: The corresponding interrupt is disabled.
1: The corresponding interrupt is enabled.
This bit is cleared when the corresponding bit in IDR is written to one.
This bit is set when the corresponding bit in IER is written to one.
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22.9.11
Name:
Status Clear Register
SCR
Access Type:
Read/Write
Offset:
0x28
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
23
22
21
20
19
18
17
16
BTF
REP
STO
SMBDAM
SMBHHM
SMBALERTM
GCM
SAM
15
14
13
12
11
10
9
8
-
BUSERR
SMBPECERR
SMBTOUT
-
-
-
NAK
7
6
5
4
3
2
1
0
ORUN
URUN
-
-
TCOMP
-
-
-
Writing a zero to a bit in this register has no effect.
Writing a one to a bit in this register will clear the corresponding bit in SR and the corresponding interrupt request.
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22.9.12
Name:
Parameter Register
PR
Access Type:
Read-only
Offset:
0x2C
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
-
This register always reads as zero. No functionality associated.
466
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22.9.13
Name:
Version Register (VR)
VR
Access Type:
Read-only
Offset:
0x30
Reset Value:
Device-specific
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
15
14
13
12
9
8
-
-
-
-
7
6
5
4
VARIANT
11
10
VERSION [11:8]
3
VERSION [7:0]
• VARIANT: Variant Number
Reserved. No functionality associated.
• VERSION: Version Number
Version number of the module. No functionality associated.
2
1
0
AT32UC3A3/A4
22.10 Module Configuration
The specific configuration for each TWIS instance is listed in the following tables.The module
bus clocks listed here are connected to the system bus clocks according to the table in the
Power Manager section.
Table 22-7.
Module Clock Name
Module name
Clock name
TWIS0
CLK_TWIS0
TWIS1
CLK_TWIS1
Table 22-8.
Register Reset Values
Register
Reset Value
VR
0x00000100
PR
0x00000000
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23. Two-Wire Master Interface (TWIM)
Rev 1.0.0.1
23.1
Features
• Compatible with I²C standard
•
•
•
•
•
•
23.2
– Multi-master support
– 100 and 400 kbit/s transfer speeds
– 7- and 10-bit and General Call addressing
Compatible with SMBus standard
– Hardware Packet Error Checking (CRC) generation and verification with ACK control
– SMBus ALERT interface
– 25 ms clock low timeout delay
– 10 ms master cumulative clock low extend time
– 25 ms slave cumulative clock low extend time
Compatible with PMBus
Compatible with Atmel Two-Wire Interface Serial Memories
DMA interface for reducing CPU load
Arbitrary transfer lengths, including 0 data bytes
Optional clock stretching if transmit or receive buffers not ready for data transfer
Overview
The Atmel Two-wire Interface Master (TWIM) interconnects components on a unique two-wire
bus, made up of one clock line and one data line with speeds of up to 400 kbit/s, based on a
byte-oriented transfer format. It can be used with any Atmel Two-wire Interface bus serial
EEPROM and I²C compatible device such as a real rime clock (RTC), dot matrix/graphic LCD
controller and temperature sensor, to name a few. TWIM is always a bus master and can transfer sequential or single bytes. Multiple master capability is supported. Arbitration of the bus is
performed internally and relinquishes the bus automatically if the bus arbitration is lost.
A configurable baud rate generator permits the output data rate to be adapted to a wide range of
core clock frequencies.Table 23-1 on page 469 lists the compatibility level of the Atmel Two-wire
Interface in Master Mode and a full I²C compatible device.
Table 23-1.
Atmel TWIM Compatibility with I²C Standard
I²C Standard
Atmel TWIM
Standard Mode Speed (100 KHz)
Supported
Fast Mode Speed (400 KHz)
Supported
7- or 10-bits Slave Addressing
Supported
(1)
START BYTE
Not Supported
Repeated Start (Sr) Condition
Supported
ACK and NACK Management
Supported
Slope Control and Input Filtering (Fast mode)
Supported
Clock Stretching
Supported
Note:
1. START + b000000001 + Ack + Sr
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Table 23-2 on page 470 lists the compatibility level of the Atmel Two-wire Master Interface and a
full SMBus compatible master.
Table 23-2.
23.3
SMBus Standard
Atmel TWIM
Bus Timeouts
Supported
Address Resolution Protocol
Supported
Alert
Supported
Host Functionality
Supported
Packet Error Checking
Supported
List of Abbreviations
Table 23-3.
23.4
Atmel TWIM Compatibility with SMBus Standard
Abbreviations
Abbreviation
Description
TWI
Two-wire Interface
A
Acknowledge
NA
Non Acknowledge
P
Stop
S
Start
Sr
Repeated Start
SADR
Slave Address
ADR
Any address except SADR
R
Read
W
Write
Block Diagram
Figure 23-1. Block Diagram
Peripheral
Bus Bridge
TWCK
I/O controller
Two-wire
Interface
Power
Manager
TWD
TWALM
CLK_TWIM
INTC
TWI Interrupt
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23.5
Application Block Diagram
Figure 23-2. Application Block Diagram
VDD
Rp
Rp
TWD
TWI
Master
TWCK
Atmel TWI
serial EEPROM
Slave 1
I²C RTC
I²C LCD
controller
I²C temp.
sensor
Slave 2
Slave 3
Slave 4
Rp: Pull up value as given by the I²C Standard
23.6
I/O Lines Description
Table 23-4.
I/O Lines Description
Pin Name
Pin Description
TWD
Two-wire Serial Data
Input/Output
TWCK
Two-wire Serial Clock
Input/Output
TWALM
SMBus SMBALERT
Input/Output
23.7
Type
Product Dependencies
In order to use this module, other parts of the system must be configured correctly, as described
below.
23.7.1
I/O Lines
Both TWD and TWCK are bidirectional lines, connected to a positive supply voltage via a current
source or pull-up resistor (see Figure 23-2 on page 471). When the bus is free, both lines are
high. The output stages of devices connected to the bus must have an open-drain or open-collector to perform the wired-AND function.
TWALM is used to implement the optional SMBus SMBALERT signal.
The TWALM, TWD, and TWCK pins may be multiplexed with I/O Controller lines. To enable the
TWIM, the programmer must perform the following steps:
• Program the I/O Controller to:
– Dedicate TWD, TWCK and optionally TWALM as peripheral lines.
– Define TWD, TWCK and optionally TWALM as open-drain.
23.7.2
Power Management
If the CPU enters a sleep mode that disables clocks used by the TWIM, the TWIM will stop functioning and resume operation after the system wakes up from sleep mode.
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23.7.3
Clocks
The clock for the TWIM bus interface (CLK_TWIM) is generated by the Power Manager. This
clock is enabled at reset, and can be disabled in the Power Manager. It is recommended to disable the TWIM before disabling the clock, to avoid freezing the TWIM in an undefined state.
23.7.4
Interrupts
The TWIM interrupt request lines are connected to the interrupt controller. Using the TWIM interrupts requires the interrupt controller to be programmed first.
23.7.5
Debug Operation
When an external debugger forces the CPU into debug mode, the TWIM continues normal operation. If the TWIM is configured in a way that requires it to be periodically serviced by the CPU
through interrupts or similar, improper operation or data loss may result during debugging.
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23.8
23.8.1
Functional Description
Transfer Format
The data put on the TWD line must be 8 bits long. Data is transferred MSB first; each byte must
be followed by an acknowledgement. The number of bytes per transfer is unlimited (see Figure
23-4 on page 473).
Each transfer begins with a START condition and terminates with a STOP condition (see Figure
23-4 on page 473).
• A high-to-low transition on the TWD line while TWCK is high defines the START condition.
• A low-to-high transition on the TWD line while TWCK is high defines a STOP condition.
Figure 23-3.
START and STOP Conditions
TWD
TWCK
Start
Stop
Figure 23-4. Transfer Format
TWD
TWCK
Start
23.8.2
Address
R/W
Ack
Data
Ack
Data
Ack
Stop
Operation
The TWIM has two modes of operation:
• Master transmitter mode
• Master receiver mode
The master is the device which starts and stops a transfer and generates the TWCK clock.
These modes are described in the following chapters.
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23.8.2.1
Clock Generation
The Clock Waveform Generator Register (CWGR) is used to control the waveform of the TWCK
clock. CWGR must be programmed so that the desired TWI bus timings are generated. CWGR
describes bus timings as a function of cycles of a prescaled clock. The clock prescaling can be
selected through the EXP field in CWGR.
f clkpb
f prescaled = ------------------------( EXP + 1 ) )
2
CWGR has the following fields:
LOW: Prescaled clock cycles in clock low count. Used to time TLOW. and TBUF.
HIGH: Prescaled clock cycles in clock high count. Used to time THIGH.
STASTO: Prescaled clock cycles in clock high count. Used to time THD_STA, TSU_STA, TSU_STO.
DATA: Prescaled clock cycles for data setup and hold count. Used to time THD_DAT, TSU_DAT.
EXP: Specifies the clock prescaler setting.
Note that the total clock low time generated is the sum of THD_DAT + TSU_DAT + TLOW.
Any slave or other bus master taking part in the transfer may extend the TWCK low period at any
time.
The TWIM hardware monitors the state of the TWCK line as required by the I²C specification.
The clock generation counters are started when a high/low level is detected on the TWCK line,
not when the TWIM hardware releases/drives the TWCK line. This means that the CWGR settings alone do not determine the TWCK frequency. The CWGR settings determine the clock low
time and the clock high time, but the TWCK rise and fall times are determined by the external circuitry (capacitive load, etc.).
Figure 23-5. Bus Timing Diagram
t HIGH
t LOW
S
t
HD:STA
t LOW
t
SU:DAT
t
HD:DAT
t
t
23.8.2.2
t
SU:DAT
SU:STA
SU:STO
P
Sr
Setting up and Performing a Transfer
Operation of TWIM is mainly controlled by the Control Register (CR) and the Command Register
(CMDR). The following list presents the main steps in a typical communication:
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1. Before any transfers can be performed, bus timings must be configured by programming the Clock Waveform Generator Register (CWGR). If operating in SMBus mode,
the SMBus Timing Register (SMBTR) register must also be configured.
2. If a DMA controller is to be used for the transfers, it must be set up.
3. CMDR or NCMDR must be programmed with a value describing the transfer to be
performed.
The interrupt system can be set up to give interrupt request on specific events or error conditions, for example when the transfer is complete or if arbitration is lost.
The controller will refuse to start a new transfer while ANAK, DNAK or ARBLST is set in the Status Register (SR). This is necessary to avoid a race when the software issues a continuation of
the current transfer at the same time as one of these errors happen. Also, if ANAK or DNAK
occur, a STOP condition is sent automatically. The programmer will have to restart the transmission by clearing the errors bit in SR after resolving the cause for the NACK.
After a data or address NACK from the slave, a STOP will be transmitted automatically. Note
that the VALID bit in CMDR is NOT cleared in this case. If this transfer is to be discarded, the
VALID bit can be cleared manually allowing any command in NCMDR to be copied into CMDR.
When a data or address NACK is returned by the slave while the master is transmitting, it is possible that new data has already been written to the THR register. This data will be transferred out
as the first data byte of the next transfer. If this behavior is to be avoided, the safest approach is
to perform a software reset of the TWIM.
23.8.3
Master Transmitter Mode
A START condition is transmitted and master transmitter mode is initiated when the bus is free
and CMDR has been written with START=1 and READ=0. START and SADR+W will then be
transmitted. During the address acknowledge clock pulse (9th pulse), the master releases the
data line (HIGH), enabling the slave to pull it down in order to acknowledge the address. The
master polls the data line during this clock pulse and sets the Address Not Acknowledged bit
(ANAK) in the Status Register if no slave acknowledges the address.
After the address phase, the following is repeated:
while (NBYTES>0)
1. Wait until THR contains a valid data byte, stretching low period of TWCK. SR.TXRDY
indicates the state of THR. Software or a DMA controller must write the data byte to
THR.
2. Transmit this data byte
3. Decrement NBYTES
4. If (NBYTES==0) and STOP=1, transmit STOP condition
Programming CMDR with START=STOP=1 and NBYTES=0 will generate a transmission with
no data bytes, ie START, SADR+W, STOP.
TWI transfers require the slave to acknowledge each received data byte. During the acknowledge clock pulse (9th pulse), the master releases the data line (HIGH), enabling the slave to pull
it down in order to generate the acknowledge. The master polls the data line during this clock
pulse and sets the Data Acknowledge bit (DNACK) in the Status Register if the slave does not
acknowledge the data byte. As with the other status bits, an interrupt can be generated if
enabled in the Interrupt Enable Register (TWIM_IER).
TXRDY is used as Transmit Ready for the Peripheral DMA Controller transmit channel.
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The end of a command is marked by setting the SR.CCOMP bit to one. See Figure 23-6 on page
476 and Figure 23-7 on page 476.
Figure 23-6. Master Write with One Data Byte
TWD
S
DADR
W
A
DATA
A
P
SR.IDLE
TXRDY
Write THR (DATA)
NBYTES set to 1
STOP sent automatically
(ACK received and NBYTES=0)
Figure 23-7. Master Write with Multiple Data Bytes
TWD
S
DADR
W
A
DATAn
A
DATAn+5
A
DATAn+m
A
P
SR.IDLE
TXRDY
Write THR
(DATAn)
NBYTES set to n
23.8.4
Write THR
(DATAn+1)
Write THR
(DATAn+m)
Last data sent
STOP sent automatically
(ACK received and NBYTES=0)
Master Receiver Mode
A START condition is transmitted and master receiver mode is initiated when the bus is free and
CMDR has been written with START=1 and READ=1. START and SADR+R will then be transmitted. During the address acknowledge clock pulse (9th pulse), the master releases the data
line (HIGH), enabling the slave to pull it down in order to acknowledge the address. The master
polls the data line during this clock pulse and sets the Address Not Acknowledged bit (ANAK) in
the Status Register if no slave acknowledges the address.
After the address phase, the following is repeated:
while (NBYTES>0)
1. Wait until RHR is empty, stretching low period of TWCK. SR.RXRDY indicates the state
of RHR. Software or a DMA controller must read any data byte present in RHR.
2. Release TWCK generating a clock that the slave uses to transmit a data byte.
3. Place the received data byte in RHR, set RXRDY.
4. If NBYTES=0, generate a NAK after the data byte, otherwise generate an ACK.
5. Decrement NBYTES
6. If (NBYTES==0) and STOP=1, transmit STOP condition.
Programming CMDR with START=STOP=1 and NBYTES=0 will generate a transmission with
no data bytes, ie START, DADR+R, STOP
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The TWI transfers require the master to acknowledge each received data byte. During the
acknowledge clock pulse (9th pulse), the slave releases the data line (HIGH), enabling the master to pull it down in order to generate the acknowledge. All data bytes except the last are
acknowledged by the master. Not acknowledging the last byte informs the slave that the transfer
is finished.
RXRDY is used as Receive Ready for the Peripheral DMA Controller receive channel.
Figure 23-8. Master Read with One Data Byte
TWD
S
DADR
R
A
DATA
N
P
SR.IDLE
RXRDY
Write START &
STOP bit
NBYTES set to 1
Read RHR
Figure 23-9. Master Read with Multiple Data Bytes
TWD
S
DADR
R
A
DATAn
A
DATAn+1
DATAn+m-1
A
DATAn+m
N
P
SR.IDLE
RXRDY
Write START +
STOP bit
NBYTES set to m
Read RHR
DATAn
Read RHR
DATAn+m-2
Read RHR
DATAn+m-1
Read RHR
DATAn+m
Send STOP
When NBYTES=0
23.8.5
Using the Peripheral DMA Controller
The use of the Peripheral DMA Controller significantly reduces the CPU load. The programmer
can set up ring buffers for the DMA controller, containing data to transmit or free buffer space to
place received data.
To assure correct behavior, respect the following programming sequences:
23.8.5.1
Data Transmit with the Peripheral DMA Controller
1. Initialize the transmit Peripheral DMA Controller (memory pointers, size, etc.).
2. Configure the TWIM (ADR, NBYTES, etc.).
3. Start the transfer by setting the Peripheral DMA Controller TXTEN bit.
4. Wait for the Peripheral DMA Controller end TX flag.
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5. Disable the Peripheral DMA Controller by setting the Peripheral DMA Controller TXDIS
bit.
23.8.5.2
Data Receive with the Peripheral DMA Controller
1. Initialize the receive Peripheral DMA Controller (memory pointers, size, etc.).
2. Configure the TWIM (ADR, NBYTES, etc.).
3. Start the transfer by setting the Peripheral DMA Controller RXTEN bit.
4. Wait for the Peripheral DMA Controller end RX flag.
5. Disable the Peripheral DMA Controller by setting the Peripheral DMA Controller RXDIS
bit.
23.8.6
Multi-master Mode
More than one master may access the bus at the same time without data corruption by using
arbitration.
Arbitration starts as soon as two or more masters place information on the bus at the same time,
and stops (arbitration is lost) for the master that intends to send a logical one while the other
master sends a logical zero.
As soon as arbitration is lost by a master, it stops sending data and listens to the bus in order to
detect a STOP. The SR.ARBLST flag will be set. When the STOP is detected, the master who
lost arbitration may reinitiate the data transfer.
Arbitration is illustrated in Figure 23-11 on page 479.
If the user starts a transfer and if the bus is busy, TWIM automatically waits for a STOP condition
on the bus before initiating the transfer (see Figure 23-10 on page 478).
Note:
The state of the bus (busy or free) is not indicated in the user interface.
Figure 23-10. Programmer Sends Data While the Bus is Busy
TWCK
START sent by the TWI
STOP sent by the master
TWD
DATA sent by a master
DATA sent by the TWI
Bus is busy
Bus is free
TWI DATA transfer
A transfer is programmed
(DADR + W + START + Write THR)
Transfer is kept
Bus is considered as free
Transfer is initiated
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Figure 23-11. Arbitration Cases
TWCK
TWD
TWCK
Data from a Master
S
1
0 0 1 1
Data from TWI
S
1
0
TWD
S
1
0 0
1
P
Arbitration is lost
TWI stops sending data
Data from the master
1 1
P
Arbitration is lost
S
1
0
S
1
0 0 1
1
S
1
0
1
1
The master stops sending data
0 1
Data from the TWI
ARBLST
Bus is busy
Transfer is kept
TWI DATA transfer
A transfer is programmed
(DADR + W + START + Write THR)
23.8.7
Bus is free
Transfer is stopped
Transfer is programmed again
(DADR + W + START + Write THR)
Bus is considered as free
Transfer is initiated
Combined Transfers
CMDR and NCMDR may be used to generate longer sequences of connected transfers, since
generation of START and/or STOP conditions is programmable on a per-command basis.
Programming NCMDR with START=1 when the previous transfer was programmed with
STOP=0 will cause a REPEATED START on the bus. The ability to generate such connected
transfers allows arbitrary transfer lengths, since it is legal to program CMDR with both START=0
and STOP=0. If this is done in master receiver mode, the CMDR.ACKLAST bit must also be
controlled.
As for single data transfers, the TXRDY and RXRDY bits in the Status Register indicates when
data to transmit can be written to the THR, or when received data can be read from RHR. Transfer of data to THR and from RHR can also be done automatically by DMA, see ”Using the
Peripheral DMA Controller” on page 477
23.8.7.1
Write Followed by Write
Consider the following transfer:
START, DADR+W, DATA+A, DATA+A, REPSTART, DADR+W, DATA+A, DATA+A, STOP.
To generate this transfer:
1. Program CMDR with START=1, STOP=0, DADR, NBYTES=2 and READ=0.
2. Program NCMDR with START=1, STOP=1, DADR, NBYTES=2 and READ=0.
3. Wait until SR.TXRDY==1, then write first data byte to transfer to THR.
4. Wait until SR.TXRDY==1, then write second data byte to transfer to THR.
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5. Wait until SR.TXRDY==1, then write third data byte to transfer to THR.
6. Wait until SR.TXRDY==1, then write fourth data byte to transfer to THR.
23.8.7.2
Read Followed by Read
Consider the following transfer:
START, DADR+R, DATA+A, DATA+NA, REPSTART, DADR+R, DATA+A, DATA+NA, STOP.
To generate this transfer:
1. Program CMDR with START=1, STOP=0, DADR, NBYTES=2 and READ=1.
2. Program NCMDR with START=1, STOP=1, DADR, NBYTES=2 and READ=1.
3. Wait until SR.RXRDY==1, then read first data byte received from RHR.
4. Wait until SR.RXRDY==1, then read second data byte received from RHR.
5. Wait until SR.RXRDY==1, then read third data byte received from RHR.
6. Wait until SR.RXRDY==1, then read fourth data byte received from RHR.
If combining several transfers, without any STOP or REPEATED START between them, remember to set the ACKLAST bit in CMDR to keep from ending each of the partial transfers with a
NACK.
23.8.7.3
Write Followed by Read
Consider the following transfer:
START, DADR+W, DATA+A, DATA+A, REPSTART, DADR+R, DATA+A, DATA+NA, STOP.
Figure 23-12. Combining a Write and Read Transfer
THR
DATA0
DATA1
RHR
TWD
DATA2
S
DADR
W
A
DATA0
A
DATA1
NA
Sr
DADR
R
A
DATA2
A
DATA3
DATA3
SR.IDLE
A
P
1
TXRDY
RXRDY
To generate this transfer:
1. Program CMDR with START=1, STOP=0, DADR, NBYTES=2 and READ=0.
2. Program NCMDR with START=1, STOP=1, DADR, NBYTES=2 and READ=1.
3. Wait until SR.TXRDY==1, then write first data byte to transfer to THR.
4. Wait until SR.TXRDY==1, then write second data byte to transfer to THR.
5. Wait until SR.RXRDY==1, then read first data byte received from RHR.
6. Wait until SR.RXRDY==1, then read second data byte received from RHR.
23.8.7.4
Read Followed by Write
Consider the following transfer:
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START, DADR+R, DATA+A, DATA+NA, REPSTART, DADR+W, DATA+A, DATA+A, STOP.
Figure 23-13. Combining a Read and Write Transfer
THR
DATA2
RHR
TWD
DATA0
S
SADR
R
A
DATA0
A
DATA3
A
DATA1
DATA3
1
Sr
DADR
W
A
DATA2
A
DATA3
NA
P
SR.IDLE
2
TXRDY
Read
TWI_RHR
RXRDY
To generate this transfer:
1. Program CMDR with START=1, STOP=0, DADR, NBYTES=2 and READ=1.
2. Program NCMDR with START=1, STOP=1, DADR, NBYTES=2 and READ=0.
3. Wait until SR.RXRDY==1, then read first data byte received from RHR.
4. Wait until SR.RXRDY==1, then read second data byte received from RHR.
5. Wait until SR.TXRDY==1, then write first data byte to transfer to THR.
6. Wait until SR.TXRDY==1, then write second data byte to transfer to THR.
23.8.8
Ten Bit Addressing
Setting CMDR.TENBIT enables 10-bit addressing in hardware. Performing transfers with 10-bit
addressing is similar to transfers with 7-bit addresses, except that bits 10:7 of CMDR.ADR must
be set appropriately.
In Figure 23-14 on page 481 and Figure 23-15 on page 482, the grey boxes represent signals
driven by the master, the white boxes are driven by the slave.
23.8.8.1
Master Transmitter
To perform a master transmitter transfer,
1. Program CMDR with TENBIT=1, REPSAME=0, READ=0, START=1, STOP=1 and the
desired address and NBYTES value.
Figure 23-14. A Write Transfer with 10-bit Addressing
1
S
23.8.8.2
1
1
1
0
X
SLAVE ADDRESS
1st 7 bits
X
0
RW A1
SLAVE ADDRESS
2nd byte
A2
DATA
A
DATA
AA P
Master Receiver
When using master receiver mode with 10-bit addressing, CMDR.REPSAME must also be controlled. CMDR.REPSAME must be written to one when the address phase of the transfer should
consist of only 1 address byte (the 11110xx byte) and not 2 address bytes. The I²C standard
specifies that such addressing is required when addressing a slave for reads using 10-bit
addressing.
To perform a master receiver transfer,
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1. Program CMDR with TENBIT=1, REPSAME=0, READ=0, START=1, STOP=0,
NBYTES=0 and the desired address.
2. Program NCMDR with TENBIT=1, REPSAME=1, READ=1, START=1, STOP=1 and
the desired address and NBYTES value.
Figure 23-15. A Read Transfer with 10-bit Addressing
1
S
23.8.9
1
1
1
0
X
X
SLAVE ADDRESS
1st 7 bits
1
0
RW A1
SLAVE ADDRESS
2nd byte
A2 Sr
1
1
1
0
X
SLAVE ADDRESS
1st 7 bits
X
1
RW A3
DATA
A
DATA
A
P
SMBus Mode
SMBus mode is enabled and disabled by the SMEN and SMDIS bits in CR. SMBus mode operation is similar to I²C operation with the following exceptions:
• Only 7-bit addressing can be used.
• The SMBus standard describes a set of timeout values to ensure progress and throughput on
the bus. These timeout values must be programmed into SMBTR.
• Transmissions can optionally include a CRC byte, called Packet Error Check (PEC).
• A dedicated bus line, SMBALERT, allows a slave to get a master’s attention.
• A set of addresses have been reserved for protocol handling, such as Alert Response
Address (ARA) and Host Header (HH) Address.
23.8.9.1
Packet Error Checking
Each SMBus transfer can optionally end with a CRC byte, called the PEC byte. Writing
CMDR.PECEN to one enables automatic PEC handling in the current transfer. Transfers with
and without PEC can freely be intermixed in the same system, since some slaves may not support PEC. The PEC LFSR is always updated on every bit transmitted or received, so that PEC
handling on combined transfers will be correct.
In master transmitter mode, the master calculates a PEC value and transmits it to the slave after
all data bytes have been transmitted. Upon reception of this PEC byte, the slave will compare it
to the PEC value it has computed itself. If the values match, the data was received correctly, and
the slave will return an ACK to the master. If the PEC values differ, data was corrupted, and the
slave will return a NACK value. The DNAK bit in SR reflects the state of the last received
ACK/NACK value. Some slaves may not be able to check the received PEC in time to return a
NACK if an error occurred. In this case, the slave should always return an ACK after the PEC
byte, and some other mechanism must be implemented to verify that the transmission was
received correctly.
In master receiver mode, the slave calculates a PEC value and transmits it to the master after all
data bytes have been transmitted. Upon reception of this PEC byte, the master will compare it to
the PEC value it has computed itself. If the values match, the data was received correctly. If the
PEC values differ, data was corrupted, and the PECERR bit in SR is set. In master receiver
mode, the PEC byte is always followed by a NACK transmitted by the master, since it is the last
byte in the transfer.
The PEC byte is automatically inserted in a master transmitter transmission if PEC is enabled
when NBYTES reaches zero. The PEC byte is identified in a master receiver transmission if
PEC is enabled when NBYTES reaches zero. NBYTES must therefore be set to the total number of data bytes in the transmission, including the PEC byte.
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In combined transfers, the PECEN bit should only be set in the last of the combined transfers.
Consider the following transfer:
S, ADR+W, COMMAND_BYTE, ACK, SR, ADR+R, DATA_BYTE, ACK, PEC_BYTE, NACK, P
This transfer is generated by writing two commands to the command registers. The first command is a write with NBYTES=1 and PECEN=0, and the second is a read with NBYTES=2 and
PECEN=1.
Writing a one to the STOP bit in CR will place a STOP condition on the bus after the current
byte. No PEC byte will be sent in this case.
23.8.9.2
Timeouts
The TLOWS and TLOWM fields in SMBTR configure the SMBus timeout values. If a timeout
occurs, the master will transmit a STOP condition and leave the bus. The SR.TOUT bit is also
set.
23.8.9.3
SMBus ALERT Signal
A slave can get the master’s attention by pulling the TWALM line low. SR.SMBAL will then be
set. This can be set up to trigger an interrupt, and software can then take the appropriate action,
as defined in the SMBus standard.
23.8.10
Identifying Bus Events
This chapter lists the different bus events, and how these affects bits in the TWIM registers. This
is intended to help writing drivers for the TWIM.
Table 23-5.
Bus Events
Event
Effect
Master transmitter has sent
a data byte
SR.THR is cleared.
Master receiver has
received a data byte
SR.RHR is set.
Start+Sadr sent, no ack
received from slave
SR.ANAK is set.
SR.CCOMP not set.
CMDR.VALID remains set.
STOP automatically transmitted on bus.
Data byte sent to slave, no
ack received from slave
SR.DNAK is set.
SR.CCOMP not set.
CMDR.VALID remains set.
STOP automatically transmitted on bus.
Arbitration lost
SR.ARBLST is set.
SR.CCOMP not set.
CMDR.VALID remains set.
TWCK and TWD immediately released to a pulled-up state.
SMBus Alert received
SR.SMBAL is set.
SMBus timeout received
SR.SMBTOUT is set.
SR.CCOMP not set.
CMDR.VALID remains set.
STOP automatically transmitted on bus.
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Table 23-5.
Bus Events
Event
Effect
Master transmitter receives
SMBus PEC Error
SR.DNAK is set.
SR.CCOMP not set.
CMDR.VALID remains set.
STOP automatically transmitted on bus.
Master receiver discovers
SMBus PEC Error
SR.PECERR is set.
SR.CCOMP not set.
CMDR.VALID remains set.
STOP automatically transmitted on bus.
CR.STOP is written by user
SR.STOP is set.
SR.CCOMP set.
CMDR.VALID remains set.
STOP transmitted on bus after current byte transfer has finished.
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23.9
User Interface
Table 23-6.
Note:
TWIM Register Memory Map
Offset
Register
Register Name
Access
Reset
0x00
Control
CR
Write-only
0x00000000
0x04
Clock Waveform Generator
CWGR
Read/Write
0x00000000
0x08
SMBus Timing
SMBTR
Read/Write
0x00000000
0x0C
Command
CMDR
Read/Write
0x00000000
0x10
Next Command
NCMDR
Read/Write
0x00000000
0x14
Receive Holding
RHR
Read-only
0x00000000
0x18
Transmit Holding
THR
Write-only
0x00000000
0x1C
Status
SR
Read-only
0x00000002
0x20
Interrupt Enable Register
IER
Write-only
0x00000000
0x24
Interrupt Disable Register
IDR
Write-only
0x00000000
0x28
Interrupt Mask Register
IMR
Read-only
0x00000000
0x2C
Status Clear Register
SCR
Write-only
0x00000000
0x30
Parameter Register
PR
Read-only
(1)
0x34
Version Register
VR
Read-only
(1)
1. The reset values for these registers are device specific. Please refer to the Module Configuration section at the end of this
chapter.
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23.9.1
Name:
Control Register (CR)
CR
Access Type:
Write-only
Offset:
0x00
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
STOP
7
6
5
4
3
2
1
0
SWRST
-
SMDIS
SMEN
-
-
MDIS
MEN
• STOP: Stop the current transfer
Writing a one to this bit terminates the current transfer, sending a STOP condition after the shifter has become idle. If there are
additional pending transfers, they will have to be explicitly restarted by software after the STOP condition has been successfully
sent.
Writing a zero to this bit has no effect.
• SWRST: Software Reset
If the TWIM master interface is enabled, writing a one to this bit resets the TWIM. All transfers are halted immediately, possibly
violating the bus semantics.
If the TWIM master interface is not enabled, it must first be enabled before writing a one to this bit.
Writing a zero to this bit has no effect.
• SMDIS: SMBus Disable
Writing a one to this bit disables SMBus mode.
Writing a zero to this bit has no effect.
• SMEN: SMBus Enable
Writing a one to this bit enables SMBus mode.
Writing a zero to this bit has no effect.
• MDIS: Master Disable
Writing a one to this bit disables the master interface.
Writing a zero to this bit has no effect.
• MEN: Master enable
Writing a one to this bit enables the master interface.
Writing a zero to this bit has no effect.
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23.9.2
Name:
Clock Waveform Generator Register (CWGR)
CWGR
Access Type:
Read/Write
Offset:
0x04
Reset Value:
0x00000000
31
30
-
29
28
27
26
EXP
23
22
21
25
24
DATA
20
19
18
17
16
11
10
9
8
3
2
1
0
STASTO
15
14
13
12
HIGH
7
6
5
4
LOW
• EXP: Clock Prescaler
Used to specify how to prescale the TWCK clock. Counters are prescaled according to the following formula
f clkpb
f prescaled = ----------------------( EXP + 1 )
2
• DATA: Data Setup and Hold Cycles
Clock cycles for data setup and hold count. Prescaled by CWGR.EXP. Used to time THD_DAT, TSU_DAT.
• STASTO: START and STOP Cycles
Clock cycles in clock high count. Prescaled by CWGR.EXP. Used to time THD_STA, TSU_STA, TSU_STO
• HIGH: Clock High Cycles
Clock cycles in clock high count. Prescaled by CWGR.EXP. Used to time THIGH.
• LOW: Clock Low Cycles
Clock cycles in clock low count. Prescaled by CWGR.EXP. Used to time TLOW, TBUF.
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23.9.3
Name:
SMBus Timing Register (SMBTR)
SMBTR
Access Type:
Read/Write
Offset:
0x08
Reset Value:
0x00000000
31
30
29
28
EXP
23
22
21
20
27
26
25
24
-
-
-
-
19
18
17
16
11
10
9
8
3
2
1
0
THMAX
15
14
13
12
TLOWM
7
6
5
4
TLOWS
• EXP: SMBus Timeout Clock prescaler
Used to specify how to prescale the TIM and TLOWM counters in SMBTR. Counters are prescaled according to the following
formula
f clkpb
f prescaled, SMBus = ----------------------( EXP + 1 )
2
• THMAX: Clock High maximum cycles
Clock cycles in clock high maximum count. Prescaled by SMBTR.EXP. Used for bus free detection. Used to time THIGH:MAX.
NOTE: Uses the prescaler specified by CWGR, NOT the prescaler specified by SMBTR.
• TLOWM: Master Clock stretch maximum cycles
Clock cycles in master maximum clock stretch count. Prescaled by SMBTR.EXP. Used to time TLOW:MEXT
• TLOWS: Slave Clock stretch maximum cycles
Clock cycles in slave maximum clock stretch count. Prescaled by SMBTR.EXP. Used to time TLOW:SEXT.
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23.9.4
Name:
Command Register (CMDR)
CMDR
Access Type:
Read/Write
Offset:
0x0C
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
ACKLAST
PECEN
23
22
21
20
19
18
17
16
10
9
8
NBYTES
15
14
13
12
11
VALID
STOP
START
REPSAME
TENBIT
7
6
5
4
3
SADR[6:0]
SADR[9:7]
2
1
0
READ
• ACKLAST: ACK Last Master RX Byte
Writing this bit to zero causes the last byte in master receive mode (when NBYTES has reached 0) to be NACKed. This is the
standard way of ending a master receiver transfer.
Writing this bit to one causes the last byte in master receive mode (when NBYTES has reached 0) to be ACKed. Used for
performing linked transfers in master receiver mode with no STOP or REPEATED START between the subtransfers. This is
needed when more than 255 bytes are to be received in one single transmission.
• PECEN: Packet Error Checking Enable
Writing this bit to zero causes the transfer not to use PEC byte verification. The PEC LFSR is still updated for every bit
transmitted or received. Must be used if SMBus mode is disabled.
Writing this bit to one causes the transfer to use PEC. PEC byte generation (if master transmitter) or PEC byte verification (if
master receiver) will be performed.
• NBYTES: Number of data bytes in transfer
The number of data bytes in the transfer. After the specified number of bytes have been transferred, a STOP condition is
transmitted if CMDR.STOP is set. In SMBus mode, if PEC is used, NBYTES includes the PEC byte, ie there are NBYTES-1
data bytes and a PEC byte.
• VALID: CMDR Valid
Writing this to zero indicates that CMDR does not contain a valid command.
Writing this to one indicates that CMDR contains a valid command. This bit is cleared when the command is finished.
• STOP: Send STOP condition
Write this bit to zero to not transmit a STOP condition after the data bytes have been transmitted.
Write this bit to one to transmit a STOP condition after the data bytes have been transmitted.
• START: Send START condition
Write this bit to zero if the transfer in CMDR should not commence with a START or REPEATED START condition.
Write this bit to one if the transfer in CMDR should commence with a START or REPEATED START condition. If the bus is free
when the command is executed, a START condition is used, if the bus is busy, a REPEATED START is used.
• REPSAME: Transfer is to same address as previous address
Only used in 10-bit addressing mode, always write to 0 in 7-bit addressing mode.
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Write this bit to one if the command in CMDR performs a repeated start to the same slave address as addressed in the previous
transfer in order to enter master receiver mode.
Write this bit to zero otherwise.
• TENBIT: Ten Bit Addressing Mode
Write this bit to zero to use 7-bit addressing mode.
Write this bit to one to use 10-bit addressing mode. Must not be used when TWIM is in SMBus mode.
• SADR: Slave Address
Address of the slave involved in the transfer. Bits 9-7 are don’t care if 7-bit addressing is used.
• READ: Transfer Direction
Write this bit to zero to let the master transmit data.
Write this bit to one to let the master receive data.
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23.9.5
Name:
Next Command Register (NCMDR)
NCMDR
Access Type:
Read/Write
Offset:
0x10
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
ACKLAST
PECEN
23
22
21
20
19
18
17
16
10
9
8
NBYTES
15
14
13
12
11
VALID
STOP
START
REPSAME
TENBIT
7
6
5
4
3
SADR[6:0]
SADR[9:7]
2
1
0
READ
This register is identical to CMDR. When the VALID bit in CMDR becomes 0, the contents of NCMDR is copied into CMDR,
clearing the VALID bit in NCMDR. If the VALID bit in CMDR is cleared when NCMDR is written, the contents are copied
immediately.
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23.9.6
Name:
Receive Holding Register (RHR)
RHR
Access Type:
Read-only
Offset:
0x14
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
RXDATA
• RXDATA: Received Data
When the RXRDY bit in the Status Register (SR) is set, this field contains a byte received from the TWI bus.
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23.9.7
Name:
Transmit Holding Register (THR)
THR
Access Type:
Write-only
Offset:
0x18
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
TXDATA
• TXDATA: Data to Transmit
Write data to be transferred on the TWI bus here.
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23.9.8
Name:
Status Register (SR)
SR
Access Type:
Read-only
Offset:
0x1C
Reset Value:
0x00000002
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
MENB
15
14
13
12
11
10
9
8
-
STOP
PECERR
TOUT
SMBALERT
ARBLST
DNAK
ANAK
7
6
5
4
3
2
1
0
-
-
BUSFREE
IDLE
CCOMP
CRDY
TXRDY
RXRDY
• MENB: Master Interface Enable
0: Master interface is disabled.
1: Master interface is enabled.
• STOP: Stop Request Accepted
This bit is set when STOP request caused by setting CR STOP has been accepted, and transfer has stopped.
This bit is cleared by writing 1 to the corresponding bit in the Status Clear Register (SCR).
• PECERR: PEC Error
This bit is set when a SMBus PEC error occurred.
This bit is cleared by writing 1 to the corresponding bit in the Status Clear Register (SCR).
• TOUT: Timeout
This bit is set when a SMBus timeout occurred.
This bit is cleared by writing 1 to the corresponding bit in the Status Clear Register (SCR).
• SMBALERT: SMBus Alert
This bit is set when an SMBus Alert was received.
This bit is cleared by writing 1 to the corresponding bit in the Status Clear Register (SCR).
• ARBLST: Arbitration Lost
This bit is set when the actual state of the SDA line did not correspond to the data driven onto it, indicating a higher-priority
transmission in progress by a different master.
This bit is cleared by writing 1 to the corresponding bit in the Status Clear Register (SCR).
• DNAK: NAK in Data Phase Received
This bit is set when no ACK was received form slave during data transmission.
This bit is cleared by writing 1 to the corresponding bit in the Status Clear Register (SCR).
• ANAK: NAK in Address Phase Received
This bit is set when no ACK was received from slave during address phase
This bit is cleared by writing 1 to the corresponding bit in the Status Clear Register (SCR).
• BUSFREE: Two-wire Bus is Free
This bit is set when activity has completed on the two-wire bus.
Otherwise, this bit is cleared.
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• IDLE: Master Interface is Idle
This bit is set when no command is in progress, and no command waiting to be issued.
Otherwise, this bit is cleared.
• CCOMP: Command Complete
This bit is set when the current command has completed successfully.
Not set if the command failed due to conditions such as a NAK receved from slave.
This bit is cleared by writing 1 to the corresponding bit in the Status Clear Register (SCR).
• CRDY: Ready for More Commands
This bit is set when CMDR and/or NCMDR is ready to receive one or more commands.
This bit is cleared when this is no longer true.
• TXRDY: THR Data Ready
This bit is set when THR is ready for one or more data bytes.
This bit is cleared when this is no longer true (i.e. THR is full or transmission has stopped).
• RXRDY: RHR Data Ready
This bit is set when RX data are ready to be read from RHR.
This bit is cleared when this is no longer true.
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23.9.9
Name:
Interrupt Enable Register (IER)
IER
Access Type:
Write-only
Offset:
0x20
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
PECERR
TOUT
SMBALERT
ARBLST
DNAK
ANAK
7
6
5
4
3
2
1
0
-
-
BUSFREE
IDLE
CCOMP
CRDY
TXRDY
RXRDY
Writing a zero to a bit in this register has no effect.
Writing a one to a bit in this register will set the corresponding bit in IMR
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23.9.10
Name:
Interrupt Disable Register (IDR)
IDR
Access Type:
Write-only
Offset:
0x24
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
PECERR
TOUT
SMBALERT
ARBLST
DNAK
ANAK
7
6
5
4
3
2
1
0
-
-
BUSFREE
IDLE
CCOMP
CRDY
TXRDY
RXRDY
Writing a zero to a bit in this register has no effect.
Writing a one to a bit in this register will clear the corresponding bit in IMR
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23.9.11
Name:
Interrupt Mask Register (IMR)
IMR
Access Type:
Read-only
Offset:
0x28
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
PECERR
TOUT
SMBALERT
ARBLST
DNAK
ANAK
7
6
5
4
3
2
1
0
-
-
BUSFREE
IDLE
CCOMP
CRDY
TXRDY
RXRDY
0: The corresponding interrupt is disabled.
1: The corresponding interrupt is enabled.
This bit is cleared when the corresponding bit in IDR is written to one.
This bit is set when the corresponding bit in IER is written to one.
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23.9.12
Name:
Status Clear Register (SCR)
SCR
Access Type :
Write-only
Offset:
0x2C
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
STOP
PECERR
TOUT
SMBALERT
ARBLST
DNAK
ANAK
7
6
5
4
3
2
1
0
-
-
-
-
CCOMP
-
-
-
Writing a zero to a bit in this register has no effect.
Writing a one to a bit in this register will clear the corresponding bit in SR and the corresponding interrupt request.
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23.9.13
Name:
Parameter Register (PR)
PR
Access Type:
Read-only
Offset:
0x30
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
-
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23.9.14
Name:
Version Register (VR)
VR
Access Type:
Read-only
Offset:
0x34
Reset Value:
Device-specific
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
15
14
13
12
9
8
-
-
-
-
7
6
5
4
VARIANT
11
10
VERSION [11:8]
3
2
1
0
VERSION [7:0]
• VARIANT: Variant number
Reserved. No functionality associated.
• VERSION: Version number
Version number of the module. No functionality associated.
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23.10 Module Configuration
The specific configuration for each TWIM instance is listed in the following tables.The module
bus clocks listed here are connected to the system bus clocks according to the table in the
Power Manager section.
Table 23-7.
Module Clock Name
Module name
Clock name
TWIM0
CLK_TWIM0
TWIM1
CLK_TWIM1
Table 23-8.
Register Reset Values
Register
Reset Value
VR
0x00000100
PR
0x00000000
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24. Synchronous Serial Controller (SSC)
Rev: 3.2.0.2
24.1
Features
•
•
•
•
•
Provides serial synchronous communication links used in audio and telecom applications
Independent receiver and transmitter, common clock divider
Interfaced with two Peripheral DMA Controller channels to reduce processor overhead
Configurable frame sync and data length
Receiver and transmitter can be configured to start automatically or on detection of different
events on the frame sync signal
• Receiver and transmitter include a data signal, a clock signal and a frame synchronization signal
24.2
Overview
The Synchronous Serial Controller (SSC) provides a synchronous communication link with
external devices. It supports many serial synchronous communication protocols generally used
in audio and telecom applications such as I2S, Short Frame Sync, Long Frame Sync, etc.
The SSC consists of a receiver, a transmitter, and a common clock divider. Both the receiver
and the transmitter interface with three signals:
• the TX_DATA/RX_DATA signal for data
• the TX_CLOCK/RX_CLOCK signal for the clock
• the TX_FRAME_SYNC/RX_FRAME_SYNC signal for the frame synchronization
The transfers can be programmed to start automatically or on different events detected on the
Frame Sync signal.
The SSC’s high-level of programmability and its two dedicated Peripheral DMA Controller channels of up to 32 bits permit a continuous high bit rate data transfer without processor
intervention.
Featuring connection to two Peripheral DMA Controller channels, the SSC permits interfacing
with low processor overhead to the following:
• CODEC’s in master or slave mode
• DAC through dedicated serial interface, particularly I2S
• Magnetic card reader
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24.3
Block Diagram
Figure 24-1. SSC Block Diagram
High
Speed
Bus
Peripheral Bus
Bridge
Peripheral DMA
Controller
Peripheral
Bus
TX_FRAME_SYNC
TX_CLOCK
TX_DATA
Power CLK_SSC
Manager
SSC Interface
I/O
Controller
RX_FRAME_SYNC
RX_CLOCK
Interrupt Control
RX_DATA
SSC Interrupt
24.4
Application Block Diagram
Figure 24-2. SSC Application Block Diagram
OS or RTOS Driver
Power
Management
Interrupt
Management
Test
Management
SSC
Serial AUDIO
Codec
Time Slot
Frame
Management Management
Line Interface
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24.5
I/O Lines Description
Table 24-1.
24.6
I/O Lines Description
Pin Name
Pin Description
Type
RX_FRAME_SYNC
Receiver Frame Synchro
Input/Output
RX_CLOCK
Receiver Clock
Input/Output
RX_DATA
Receiver Data
Input
TX_FRAME_SYNC
Transmitter Frame Synchro
Input/Output
TX_CLOCK
Transmitter Clock
Input/Output
TX_DATA
Transmitter Data
Output
Product Dependencies
In order to use this module, other parts of the system must be configured correctly, as described
below.
24.6.1
I/O Lines
The pins used for interfacing the compliant external devices may be multiplexed with I/O lines.
Before using the SSC receiver, the I/O Controller must be configured to dedicate the SSC
receiver I/O lines to the SSC peripheral mode.
Before using the SSC transmitter, the I/O Controller must be configured to dedicate the SSC
transmitter I/O lines to the SSC peripheral mode.
24.6.2
Clocks
The clock for the SSC bus interface (CLK_SSC) is generated by the Power Manager. This clock
is enabled at reset, and can be disabled in the Power Manager. It is recommended to disable the
SSC before disabling the clock, to avoid freezing the SSC in an undefined state.
24.6.3
Interrupts
The SSC interrupt request line is connected to the interrupt controller. Using the SSC interrupt
requires the interrupt controller to be programmed first.
24.7
Functional Description
This chapter contains the functional description of the following: SSC functional block, clock
management, data framing format, start, transmitter, receiver, and frame sync.
The receiver and the transmitter operate separately. However, they can work synchronously by
programming the receiver to use the transmit clock and/or to start a data transfer when transmission starts. Alternatively, this can be done by programming the transmitter to use the receive
clock and/or to start a data transfer when reception starts. The transmitter and the receiver can
be programmed to operate with the clock signals provided on either the TX_CLOCK or
RX_CLOCK pins. This allows the SSC to support many slave-mode data transfers. The maximum clock speed allowed on the TX_CLOCK and RX_CLOCK pins is CLK_SSC divided by two.
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Figure 24-3. SSC Functional Block Diagram
Transmitter
Clock Output
Controller
TX_CLOCK
Frame Sync
Controller
TX_FRAME_SYNC
TX_CLOCK Input
CLK_SSC Clock
Divider
Transmit Clock TX clock
Controller
RX clock
TX_FRAME_SYNC
RX_FRAME_SYNC
Start
Selector
Transmit Shift Register
Transmit Holding
Register
TX_DMA
Peripheral
Bus
TX_DATA
Transmit Sync
Holding Register
Load Shift
User
Interface
Receiver
RX_CLOCK
Input
TX clock
TX_FRAME_SYNC
RX_FRAME_SYNC
Receive Clock RX clock
Controller
Start
Selector
Interrupt Control
RX_CLOCK
Frame Sync
Controller
RX_FRAME_SYNC
Receive Shift Register
RX_DMA
DMA
Clock Output
Controller
Receive Holding
Register
RX_DATA
Receive Sync
Holding Register
Load Shift
Interrupt Controller
24.7.1
Clock Management
The transmitter clock can be generated by:
• an external clock received on the TX_CLOCK pin
• the receiver clock
• the internal clock divider
The receiver clock can be generated by:
• an external clock received on the RX_CLOCK pin
• the transmitter clock
• the internal clock divider
Furthermore, the transmitter block can generate an external clock on the TX_CLOCK pin, and
the receiver block can generate an external clock on the RX_CLOCK pin.
This allows the SSC to support many Master and Slave Mode data transfers.
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24.7.1.1
Clock divider
Figure 24-4. Divided Clock Block Diagram
Clock Divider
CMR
CLK_SSC
/2
12-bit Counter
Divided Clock
The peripheral clock divider is determined by the 12-bit Clock Divider field (its maximal value is
4095) in the Clock Mode Register (CMR.DIV), allowing a peripheral clock division by up to 8190.
The divided clock is provided to both the receiver and transmitter. When this field is written to
zero, the clock divider is not used and remains inactive.
When CMR.DIV is written to a value equal to or greater than one, the divided clock has a frequency of CLK_SSC divided by two times CMR.DIV. Each level of the divided clock has a
duration of the peripheral clock multiplied by CMR.DIV. This ensures a 50% duty cycle for the
divided clock regardless of whether the CMR.DIV value is even or odd.
Figure 24-5.
Divided Clock Generation
CLK_SSC
Divided Clock
DIV = 1
Divided Clock Frequency = CLK_SSC/2
CLK_SSC
Divided Clock
DIV = 3
Divided Clock Frequency = CLK_SSC/6
Table 24-2.
24.7.1.2
Range of Clock Divider
Maximum
Minimum
CLK_SSC / 2
CLK_SSC / 8190
Transmitter clock management
The transmitter clock is generated from the receiver clock, the divider clock, or an external clock
scanned on the TX_CLOCK pin. The transmitter clock is selected by writing to the Transmit
Clock Selection field in the Transmit Clock Mode Register (TCMR.CKS). The transmit clock can
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be inverted independently by writing a one to the Transmit Clock Inversion bit in TCMR
(TCMR.CKI).
The transmitter can also drive the TX_CLOCK pin continuously or be limited to the actual data
transfer, depending on the Transmit Clock Output Mode Selection field in the TCMR register
(TCMR.CKO). The TCMR.CKI bit has no effect on the clock outputs.
Writing 0b10 to the TCMR.CKS field to select TX_CLOCK pin and 0b001 to the TCMR.CKO field
to select Continuous Transmit Clock can lead to unpredictable results.
Figure 24-6. Transmitter Clock Management
TX_CLOCK
Clock
Output
Tri-state
Controller
MUX
Receiver
Clock
Divider
Clock
Data Transfer
CKO
CKS
24.7.1.3
INV
MUX
Tri-state
Controller
CKI
CKG
Transmitter
Clock
Receiver clock management
The receiver clock is generated from the transmitter clock, the divider clock, or an external clock
scanned on the RX_CLOCK pin. The receive clock is selected by writing to the Receive Clock
Selection field in the Receive Clock Mode Register (RCMR.CKS). The receive clock can be
inverted independently by writing a one to the Receive Clock Inversion bit in RCMR
(RCMR.CKI).
The receiver can also drive the RX_CLOCK pin continuously or be limited to the actual data
transfer, depending on the Receive Clock Output Mode Selection field in the RCMR register
(RCMR.CKO). The RCMR.CKI bit has no effect on the clock outputs.
Writing 0b10 to the RCMR.CKS field to select RX_CLOCK pin and 0b001 to the RCMR.CKO
field to select Continuous Receive Clock can lead to unpredictable results.
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Figure 24-7. Receiver Clock Management
RX_CLOCK
Tri-state
Controller
MUX
Clock
Output
Transmitter
Clock
Divider
Clock
Data Transfer
CKO
CKS
24.7.1.4
INV
MUX
Tri-state
Controller
CKI
CKG
Receiver
Clock
Serial clock ratio considerations
The transmitter and the receiver can be programmed to operate with the clock signals provided
on either the TX_CLOCK or RX_CLOCK pins. This allows the SSC to support many slave-mode
data transfers. In this case, the maximum clock speed allowed on the RX_CLOCK pin is:
– CLK_SSC divided by two if RX_FRAME_SYNC is input.
– CLK_SSC divided by three if RX_FRAME_SYNC is output.
In addition, the maximum clock speed allowed on the TX_CLOCK pin is:
– CLK_SSC divided by six if TX_FRAME_SYNC is input.
– CLK_SSC divided by two if TX_FRAME_SYNC is output.
24.7.2
Transmitter Operations
A transmitted frame is triggered by a start event and can be followed by synchronization data
before data transmission.
The start event is configured by writing to the TCMR register. See Section 24.7.4.
The frame synchronization is configured by writing to the Transmit Frame Mode Register
(TFMR). See Section 24.7.5.
To transmit data, the transmitter uses a shift register clocked by the transmitter clock signal and
the start mode selected in the TCMR register. Data is written by the user to the Transmit Holding
Register (THR) then transferred to the shift register according to the data format selected.
When both the THR and the transmit shift registers are empty, the Transmit Empty bit is set in
the Status Register (SR.TXEMPTY). When the THR register is transferred in the transmit shift
register, the Transmit Ready bit is set in the SR register (SR.TXREADY) and additional data can
be loaded in the THR register.
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Figure 24-8. Transmitter Block Diagram
CR.TXEN
SR.TXEN
CR.TXDIS
TFMR.DATDEF
1
TX_FRAME_SYNC
RX_FRAME_SYNC
Transmitter Clock
Start
Selector
TX_DATA
0
TFMR.MSBF
Transmit Shift Register
0
TFMR.FSDEN
TCMR.STTDLY
TFMR.DATLEN
24.7.3
TCMR.STTDLY
TFMR.FSDEN
TFMR.DATNB
THR
1
TSHR
TFMR.FSLEN
Receiver Operations
A received frame is triggered by a start event and can be followed by synchronization data
before data transmission.
The start event is configured by writing to the RCMR register. See Section 24.7.4.
The frame synchronization is configured by writing to the Receive Frame Mode Register
(RFMR). See Section 24.7.5.
The receiver uses a shift register clocked by the receiver clock signal and the start mode
selected in the RCMR register. The data is transferred from the shift register depending on the
data format selected.
When the receiver shift register is full, the SSC transfers this data in the Receive Holding Register (RHR), the Receive Ready bit is set in the SR register (SR.RXREADY) and the data can be
read in the RHR register. If another transfer occurs before a read of the RHR register , the
Receive Overrun bit is set in the SR register (SR.OVRUN) and the receiver shift register is transferred to the RHR register.
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Figure 24-9. Receiver Block Diagram
RX_CLO CK
T ri-sta te
C o n tro lle r
MUX
C lo ck
O u tp u t
T ra n sm itte r
C lo ck
D ivid e r
C lo ck
D a ta T ra n sfe r
CKO
CKS
24.7.4
IN V
MUX
T ri-sta te
C o n tro lle r
CKI
CKG
R e ce ive r
C lo ck
Start
The transmitter and receiver can both be programmed to start their operations when an event
occurs, respectively in the Transmit Start Selection field of the TCMR register (TCMR.START)
and in the Receive Start Selection field of the RCMR register (RCMR.START).
Under the following conditions the start event is independently programmable:
• Continuous: in this case, the transmission starts as soon as a word is written to the THR
register and the reception starts as soon as the receiver is enabled
• Synchronously with the transmitter/receiver
• On detection of a falling/rising edge on TX_FRAME_SYNC/RX_FRAME_SYNC
• On detection of a low/high level on TX_FRAME_SYNC/RX_FRAME_SYNC
• On detection of a level change or an edge on TX_FRAME_SYNC/RX_FRAME_SYNC
A start can be programmed in the same manner on either side of the Transmit/Receive Clock
Mode Register (TCMR/RCMR). Thus, the start could be on TX_FRAME_SYNC (transmit) or
RX_FRAME_SYNC (receive).
Moreover, the receiver can start when data is detected in the bit stream with the compare functions. See Section 24.7.6 for more details on receive compare modes.
Detection on TX_FRAME_SYNC input/output is done by the Transmit Frame Sync Output
Selection field in the TFMR register (TFMR.FSOS). Similarly, detection on RX_FRAME_SYNC
input/output is done by the Receive Frame Output Sync Selection field in the RFMR register
(RFMR.FSOS).
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Figure 24-10. Transmit Start Mode
TX_CLOCK (Input)
TX_FRAME_SYNC (Input)
TX_DATA (Output)
Start= Low Level on TX_FRAME_SYNC
TX_DATA (Output)
Start= Falling Edge on TX_FRAME_SYNC
X
B0
B0
X
TX_DATA (Output)
Start= High Level on TX_FRAME_SYNC
STTDLY
B0
B0
B1
STTDLY
X
X
B1
STTDLY
X
TX_DATA (Output)
Start= Level Change on TX_FRAME_SYNC
STTDLY
B1
X
TX_DATA (Output)
Start= Rising Edge on TX_FRAME_SYNC
TX_DATA (Output)
Start= Any Edge on TX_FRAME_SYNC
B1
B0
B0
B1
B0
B1
B0
B1
B1
STTDLY
STTDLY
Figure 24-11. Receive Pulse/Edge Start Modes
RX_CLOCK
RX_FRAME_SYNC (Input)
RX_DATA (Input)
X
Start = Low Level on RX_FRAME_SYNC
RX_DATA (Input)
Start = Falling Edge on RX_FRAME_SYNC
STTDLY
B0
X
RX_DATA (Input)
B0
B1
STTDLY
RX_DATA (Input)
B0
B1
B0
B1
B0
B1
B0
B1
X
Start = Rising Edge on RX_FRAME_SYNC
RX_DATA (Input)
X
Start = Level Change on RX_FRAME_SYNC
RX_DATA (Input)
STTDLY
X
Start = High Level on RX_FRAME_SYNC
Start = Any Edge on RX_FRAME_SYNC
B1
X
B0
STTDLY
B1
STTDLY
STTDLY
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24.7.5
Frame Sync
The transmitter and receiver frame synchro pins, TX_FRAME_SYNC and RX_FRAME_SYNC,
can be programmed to generate different kinds of frame synchronization signals. The
RFMR.FSOS and TFMR.FSOS fields are used to select the required waveform.
• Programmable low or high levels during data transfer are supported.
• Programmable high levels before the start of data transfers or toggling are also supported.
If a pulse waveform is selected, in reception, the Receive Frame Sync Length High Part and the
Receive Frame Sync Length fields in the RFMR register (RFMR.FSLENHI and RFMR.FSLEN)
define the length of the pulse, from 1 bit time up to 256 bit time.
Reception Pulse Length = ((16 × FSLENHI ) + FSLEN + 1) receive clock periods
Similarly, in transmission, the Transmit Frame Sync Length High Part and the Transmit Frame
Sync Length fields in the TFMR register (TFMR.FSLENHI and TFMR.FSLEN) define the length
of the pulse, from 1 bit up to 256 bit time.
Transmission Pulse Length = ((16 × FSLENHI ) + FSLEN + 1) transmit clock periods
The periodicity of the RX_FRAME_SYNC and TX_FRAME_SYNC pulse outputs can be configured respectively through the Receive Period Divider Selection field in the RCMR register
(RCMR.PERIOD) and the Transmit Period Divider Selection field in the TCMR register
(TCMR.PERIOD).
24.7.5.1
Frame sync data
Frame Sync Data transmits or receives a specific tag during the Frame Sync signal.
During the Frame Sync signal, the receiver can sample the RX_DATA line and store the data in
the Receive Sync Holding Register (RSHR) and the transmitter can transfer the Transmit Sync
Holding Register (TSHR) in the shifter register.
The data length to be sampled in reception during the Frame Sync signal shall be written to the
RFMR.FSLENHI and RFMR.FSLEN fields.
The data length to be shifted out in transmission during the Frame Sync signal shall be written to
the TFMR.FSLENHI and TFMR.FSLEN fields.
Concerning the Receive Frame Sync Data operation, if the Frame Sync Length is equal to or
lower than the delay between the start event and the actual data reception, the data sampling
operation is performed in the RSHR through the receive shift register.
The Transmit Frame Sync operation is performed by the transmitter only if the Frame Sync Data
Enable bit in TFMR register (TFMR.FSDEN) is written to one. If the Frame Sync length is equal
to or lower than the delay between the start event and the actual data transmission, the normal
transmission has priority and the data contained in the TSHR is transferred in the transmit register, then shifted out.
24.7.5.2
Frame sync edge detection
The Frame Sync Edge detection is configured by writing to the Frame Sync Edge Detection bit in
the RFMR/TFMR registers (RFMR.FSEDGE and TFMR.FSEDGE). This sets the Receive Sync
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and Transmit Sync bits in the SR register (SR.RXSYN and SR.TXSYN) on frame synchro edge
detection (signals RX_FRAME_SYNC/TX_FRAME_SYNC).
24.7.6
Receive Compare Modes
Figure 24-12. Receive Compare Modes
RX_CLOCK
RX_DATA
(Input)
CMP0
CMP1
CMP2
Ignored
CMP3
B1
B0
B2
Start
{FSLENHI,FSLEN}
Up to 256 Bits
(4 in This Example)
24.7.6.1
24.7.7
DATLEN
STTDLY
Compare functions
Compare 0 can be one start event of the receiver. In this case, the receiver compares at each
new sample the last {RFMR.FSLENHI, RFMR.FSLEN} bits received to the {RFMR.FSLENHI,
RFMR.FSLEN} lower bits of the data contained in the Receive Compare 0 Register (RC0R).
When this start event is selected, the user can program the receiver to start a new data transfer
either by writing a new Compare 0, or by receiving continuously until Compare 1 occurs. This
selection is done with the Receive Stop Selection bit in the RCMR register (RCMR.STOP).
Data Framing Format
The data framing format of both the transmitter and the receiver are programmable through the
TFMR, TCMR, RFMR, and RCMR registers. In either case, the user can independently select:
• the event that starts the data transfer (RCMR.START and TCMR.START)
• the delay in number of bit periods between the start event and the first data bit
(RCMR.STTDLY and TCMR.STTDLY)
• the length of the data (RFMR.DATLEN and TFMR.DATLEN)
• the number of data to be transferred for each start event (RFMR.DATNB and TFMR.DATLEN)
• the length of synchronization transferred for each start event (RFMR.FSLENHI,
RFMR.FSLEN, TFMR.FSLENHI, and TFMR.FSLEN)
• the bit sense: most or lowest significant bit first (RFMR.MSBF and TFMR.MSBF)
Additionally, the transmitter can be used to transfer synchronization and select the level driven
on the TX_DATA pin while not in data transfer operation. This is done respectively by writing to
the Frame Sync Data Enable and the Data Default Value bits in the TFMR register
(TFMR.FSDEN and TFMR.DATDEF).
Table 24-3.
Data Framing Format Registers
Transmitter
Receiver
Bit/Field
Length
TCMR
RCMR
PERIOD
Up to 512
TCMR
RCMR
START
TCMR
RCMR
STTDLY
Comment
Frame size
Start selection
Up to 255
Size of transmit start delay
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Table 24-3.
Data Framing Format Registers
Transmitter
Receiver
Bit/Field
Length
Comment
TFMR
RFMR
DATNB
Up to 16
Number of words transmitted in
frame
TFMR
RFMR
DATLEN
Up to 32
Size of word
TFMR
RFMR
{FSLENHI,FSLEN}
Up to 256
Size of Synchro data register
TFMR
RFMR
MSBF
Most significant bit first
TFMR
FSDEN
Enable send TSHR
TFMR
DATDEF
Data default value ended
Figure 24-13. Transmit and Receive Frame Format in Edge/Pulse Start Modes
Start
Start
PERIOD
TX_FRAME_SYNC
/
(1)
RX_FRAME_SYNC
FSLEN
TX_DATA
(If FSDEN = 1)
Sync Data
From TSHR
TX_DATA
(If FSDEN = 0)
Default
From DATDEF
Default
From DATDEF
RX_DATA
Sync Data
Ignored
To RSHR
Data
Data
From THR
From THR
Data
Data
From THR
From THR
Data
Data
To RHR
To RHR
DATLEN
STTDLY
Default
Sync Data
From DATDEF
Default
From DATDEF
Ignored
Sync Data
DATLEN
DATNB
Note:
Example of input on falling edge of TX_FRAME_SYNC/RX_FRAME_SYNC.
Figure 24-14. Transmit Frame Format in Continuous Mode
Start
TX_DATA
Data
Data
From THR
From THR
DATLEN
DATLEN
Default
Start: 1. TXEMPTY set to one
2. Write into the THR
Note:
STTDLY is written to zero. In this example, THR is loaded twice. FSDEN value has no effect on the
transmission. SyncData cannot be output in continuous mode.
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Figure 24-15. Receive Frame Format in Continuous Mode
Start = Enable Receiver
RX_DATA
Note:
24.7.8
Data
Data
To RHR
To RHR
DATLEN
DATLEN
STTDLY is written to zero.
Loop Mode
The receiver can be programmed to receive transmissions from the transmitter. This is done by
writing a one to the Loop Mode bit in RFMR register (RFMR.LOOP). In this case, RX_DATA is
connected to TX_DATA, RX_FRAME_SYNC is connected to TX_FRAME_SYNC and
RX_CLOCK is connected to TX_CLOCK.
24.7.9
Interrupt
Most bits in the SR register have a corresponding bit in interrupt management registers.
The SSC can be programmed to generate an interrupt when it detects an event. The interrupt is
controlled by writing to the Interrupt Enable Register (IER) and Interrupt Disable Register (IDR).
These registers enable and disable, respectively, the corresponding interrupt by setting and
clearing the corresponding bit in the Interrupt Mask Register (IMR), which controls the generation of interrupts by asserting the SSC interrupt line connected to the interrupt controller.
Figure 24-16. Interrupt Block Diagram
IM R
IE R
ID R
C le a r
Set
T ra n s m itte r
TXRDY
TXEM PTY
TXSYNC
In te rru p t
C o n tro l
S S C In te rru p t
R e c e iv e r
RXRDY
OVRUN
RXSYNC
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24.8
SSC Application Examples
The SSC can support several serial communication modes used in audio or high speed serial
links. Some standard applications are shown in the following figures. All serial link applications
supported by the SSC are not listed here.
Figure 24-17. Audio Application Block Diagram
Clock SCK
TX_CLOCK
Word Select WS
I2S
RECEIVER
TX_FRAME_SYNC
Data SD
TX_DATA
SSC
RX_DATA
RX_FRAME_SYNC
Clock SCK
Word Select WS
RX_CLOCK
Data SD
MSB
LSB
Left Channel
MSB
Right Channel
Figure 24-18. Codec Application Block Diagram
Serial Data Clock (SCLK)
TX_CLOCK
Frame sync (FSYNC)
TX_FRAME_SYNC
TX_DATA
Serial Data Out
CODEC
SSC
RX_DATA
RX_FRAME_SYNC
RX_CLOCK
Serial Data In
Serial Data Clock (SCLK)
Frame sync (FSYNC)
First Time Slot
Dstart
Dend
Serial Data Out
Serial Data In
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Figure 24-19. Time Slot Application Block Diagram
SCLK
TX_CLOCK
FSYNC
TX_FRAME_SYNC
TX_DATA
CODEC
First
Time Slot
Data Out
SSC
RX_DATA
Data in
RX_FRAME_SYNC
RX_CLOCK
CODEC
Second
Time Slot
Serial Data Clock (SCLK)
Frame sync (FSYNC)
First Time Slot
Dstart
Second Time Slot
Dend
Serial Data Out
Serial Data In
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24.9
User Interface
Table 24-4.
SSC Register Memory Map
Offset
Register
Register Name
Access
Reset
0x00
Control Register
CR
Write-only
0x00000000
0x04
Clock Mode Register
CMR
Read/Write
0x00000000
0x10
Receive Clock Mode Register
RCMR
Read/Write
0x00000000
0x14
Receive Frame Mode Register
RFMR
Read/Write
0x00000000
0x18
Transmit Clock Mode Register
TCMR
Read/Write
0x00000000
0x1C
Transmit Frame Mode Register
TFMR
Read/Write
0x00000000
0x20
Receive Holding Register
RHR
Read-only
0x00000000
0x24
Transmit Holding Register
THR
Write-only
0x00000000
0x30
Receive Synchronization Holding Register
RSHR
Read-only
0x00000000
0x34
Transmit Synchronization Holding Register
TSHR
Read/Write
0x00000000
0x38
Receive Compare 0 Register
RC0R
Read/Write
0x00000000
0x3C
Receive Compare 1 Register
RC1R
Read/Write
0x00000000
0x40
Status Register
SR
Read-only
0x000000CC
0x44
Interrupt Enable Register
IER
Write-only
0x00000000
0x48
Interrupt Disable Register
IDR
Write-only
0x00000000
0x4C
Interrupt Mask Register
IMR
Read-only
0x00000000
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24.9.1
Name:
Control Register
CR
Access Type:
Write-only
Offset:
0x00
Reset value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
SWRST
-
-
-
-
-
TXDIS
TXEN
7
6
5
4
3
2
1
0
-
-
-
-
-
-
RXDIS
RXEN
• SWRST: Software Reset
1: Writing a one to this bit will perform a software reset. This software reset has priority on any other bit in CR.
0: Writing a zero to this bit has no effect.
• TXDIS: Transmit Disable
1: Writing a one to this bit will disable the transmission. If a character is currently being transmitted, the disable occurs at the end
of the current character transmission.
0: Writing a zero to this bit has no effect.
• TXEN: Transmit Enable
1: Writing a one to this bit will enable the transmission if the TXDIS bit is not written to one.
0: Writing a zero to this bit has no effect.
• RXDIS: Receive Disable
1: Writing a one to this bit will disable the reception. If a character is currently being received, the disable occurs at the end of
current character reception.
0: Writing a zero to this bit has no effect.
• RXEN: Receive Enable
1: Writing a one to this bit will enables the reception if the RXDIS bit is not written to one.
0: Writing a zero to this bit has no effect.
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24.9.2
Name:
Clock Mode Register
CMR
Access Type:
Read/Write
Offset:
0x04
Reset value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
7
6
5
4
1
0
DIV[11:8]
3
2
DIV[7:0]
• DIV[11:0]: Clock Divider
The divided clock equals the CLK_SSC divided by two times DIV. The maximum bit rate is CLK_SSC/2. The minimum bit rate is
CLK_SSC/(2 x 4095) = CLK_SSC/8190.
The clock divider is not active when DIV equals zero.
Divided Clock = CLK_SSC ⁄ ( DIV × 2)
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24.9.3
Name:
Receive Clock Mode Register
RCMR
Access Type:
Read/Write
Offset:
0x10
Reset value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
1
0
PERIOD
23
22
21
20
STTDLY
15
14
13
12
-
-
-
STOP
7
6
5
4
CKG
CKI
START
3
CKO
2
CKS
• PERIOD: Receive Period Divider Selection
This field selects the divider to apply to the selected receive clock in order to generate a periodic Frame Sync Signal.
If equal to zero, no signal is generated.
If not equal to zero, a signal is generated each 2 x (PERIOD+1) receive clock periods.
• STTDLY: Receive Start Delay
If STTDLY is not zero, a delay of STTDLY clock cycles is inserted between the start event and the actual start of reception.
When the receiver is programmed to start synchronously with the transmitter, the delay is also applied.
Note: It is very important that STTDLY be written carefully. If STTDLY must be written, it should be done in relation to Receive
Sync Data reception.
• STOP: Receive Stop Selection
1: After starting a receive with a Compare 0, the receiver operates in a continuous mode until a Compare 1 is detected.
0: After completion of a data transfer when starting with a Compare 0, the receiver stops the data transfer and waits for a new
Compare 0.
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• START: Receive Start Selection
START
Receive Start
0
Continuous, as soon as the receiver is enabled, and immediately after the end of
transfer of the previous data.
1
Transmit start
2
Detection of a low level on RX_FRAME_SYNC signal
3
Detection of a high level on RX_FRAME_SYNC signal
4
Detection of a falling edge on RX_FRAME_SYNC signal
5
Detection of a rising edge on RX_FRAME_SYNC signal
6
Detection of any level change on RX_FRAME_SYNC signal
7
Detection of any edge on RX_FRAME_SYNC signal
8
Compare 0
Others
Reserved
• CKG: Receive Clock Gating Selection
CKG
Receive Clock Gating
0
None, continuous clock
1
Receive Clock enabled only if RX_FRAME_SYNC is low
2
Receive Clock enabled only if RX_FRAME_SYNC is high
3
Reserved
• CKI: Receive Clock Inversion
CKI affects only the receive clock and not the output clock signal.
1: The data inputs (Data and Frame Sync signals) are sampled on receive clock rising edge. The Frame Sync signal output is
shifted out on receive clock falling edge.
0: The data inputs (Data and Frame Sync signals) are sampled on receive clock falling edge. The Frame Sync signal output is
shifted out on receive clock rising edge.
• CKO: Receive Clock Output Mode Selection
CKO
Receive Clock Output Mode
RX_CLOCK pin
0
None
1
Continuous receive clock
Output
2
Receive clock only during data transfers
Output
Others
Input-only
Reserved
• CKS: Receive Clock Selection
CKS
Selected Receive Clock
0
Divided clock
1
TX_CLOCK clock signal
2
RX_CLOCK pin
3
Reserved
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24.9.4
Name:
Receive Frame Mode Register
RFMR
Access Type:
Read/Write
Offset:
0x14
Reset value:
0x00000000
31
30
29
28
FSLENHI
23
22
-
21
20
27
26
25
24
-
-
-
FSEDGE
19
18
17
16
9
8
1
0
FSOS
FSLEN
15
14
13
12
-
-
-
-
7
6
5
4
MSBF
-
LOOP
11
10
DATNB
3
2
DATLEN
• FSLENHI: Receive Frame Sync Length High Part
The four MSB of the FSLEN field.
• FSEDGE: Receive Frame Sync Edge Detection
Determines which edge on Frame Sync will generate the SR.RXSYN interrupt.
FSEDGE
Frame Sync Edge Detection
0
Positive edge detection
1
Negative edge detection
• FSOS: Receive Frame Sync Output Selection
FSOS
Selected Receive Frame Sync Signal
RX_FRAME_SYNC Pin
0
None
1
Negative Pulse
Output
2
Positive Pulse
Output
3
Driven Low during data transfer
Output
4
Driven High during data transfer
Output
5
Toggling at each start of data transfer
Output
Others
Reserved
Input-only
Undefined
• FSLEN: Receive Frame Sync Length
This field defines the length of the Receive Frame Sync signal and the number of bits sampled and stored in the RSHR register.
When this mode is selected by the RCMR.START field, it also determines the length of the sampled data to be compared to the
Compare 0 or Compare 1 register.
Note: The four most significant bits for this field are located in the FSLENHI field.
The pulse length is equal to ({FSLENHI,FSLEN} + 1) receive clock periods. Thus, if {FSLENHI,FSLEN} is zero, the Receive
Frame Sync signal is generated during one receive clock period.
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• DATNB: Data Number per Frame
This field defines the number of data words to be received after each transfer start, which is equal to (DATNB + 1).
• MSBF: Most Significant Bit First
1: The most significant bit of the data register is sampled first in the bit stream.
0: The lowest significant bit of the data register is sampled first in the bit stream.
• LOOP: Loop Mode
1: RX_DATA is driven by TX_DATA, RX_FRAME_SYNC is driven by TX_FRAME_SYNC and TX_CLOCK drives RX_CLOCK.
0: Normal operating mode.
• DATLEN: Data Length
The bit stream contains (DATLEN + 1) data bits.
This field also defines the transfer size performed by the Peripheral DMA Controller assigned to the receiver.
DATLEN
0
Transfer Size
Forbidden value
1-7
Data transfer are in bytes
8-15
Data transfer are in halfwords
Others
Data transfer are in words
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24.9.5
Name:
Transmit Clock Mode Register
TCMR
Access Type:
Read/Write
Offset:
0x18
Reset value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
1
0
PERIOD
23
22
21
20
STTDLY
15
14
13
12
-
-
-
-
7
6
5
4
CKG
CKI
START
3
CKO
2
CKS
• PERIOD: Transmit Period Divider Selection
This field selects the divider to apply to the selected transmit clock in order to generate a periodic Frame Sync Signal.
If equal to zero, no signal is generated.
If not equal to zero, a signal is generated each 2 x (PERIOD+1) transmit clock periods.
• STTDLY: Transmit Start Delay
If STTDLY is not zero, a delay of STTDLY clock cycles is inserted between the start event and the actual start of transmission.
When the transmitter is programmed to start synchronously with the receiver, the delay is also applied.
Note: STTDLY must be written carefully, in relation to Transmit Sync Data transmission.
• START: Transmit Start Selection
START
Transmit Start
0
Continuous, as soon as a word is written to the THR Register (if Transmit is enabled), and
immediately after the end of transfer of the previous data.
1
Receive start
2
Detection of a low level on TX_FRAME_SYNC signal
3
Detection of a high level on TX_FRAME_SYNC signal
4
Detection of a falling edge on TX_FRAME_SYNC signal
5
Detection of a rising edge on TX_FRAME_SYNC signal
6
Detection of any level change on TX_FRAME_SYNC signal
7
Detection of any edge on TX_FRAME_SYNC signal
Others
Reserved
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• CKG: Transmit Clock Gating Selection
CKG
Transmit Clock Gating
0
None, continuous clock
1
Transmit Clock enabled only if TX_FRAME_SYNC is low
2
Transmit Clock enabled only if TX_FRAME_SYNC is high
3
Reserved
• CKI: Transmit Clock Inversion
CKI affects only the Transmit Clock and not the output clock signal.
1: The data outputs (Data and Frame Sync signals) are shifted out on transmit clock rising edge. The Frame sync signal input is
sampled on transmit clock falling edge.
0: The data outputs (Data and Frame Sync signals) are shifted out on transmit clock falling edge. The Frame sync signal input is
sampled on transmit clock rising edge.
• CKO: Transmit Clock Output Mode Selection
CKO
Transmit Clock Output Mode
TX_CLOCK pin
0
None
1
Continuous transmit clock
Output
2
Transmit clock only during data transfers
Output
Others
Input-only
Reserved
• CKS: Transmit Clock Selection
CKS
Selected Transmit Clock
0
Divided Clock
1
RX_CLOCK clock signal
2
TX_CLOCK Pin
3
Reserved
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24.9.6
Name:
Transmit Frame Mode Register
TFMR
Access Type:
Read/Write
Offset:
0x1C
Reset value:
0x00000000
31
30
29
28
FSLENHI
23
22
21
FSDEN
20
27
26
25
24
-
-
-
FSEDGE
19
18
17
16
9
8
1
0
FSOS
FSLEN
15
14
13
12
-
-
-
-
7
6
5
4
MSBF
-
DATDEF
11
10
DATNB
3
2
DATLEN
• FSLENHI: Transmit Frame Sync Length High Part
The four MSB of the FSLEN field.
• FSEDGE: Transmit Frame Sync Edge Detection
Determines which edge on Frame Sync will generate the SR.TXSYN interrupt.
FSEDGE
Frame Sync Edge Detection
0
Positive Edge Detection
1
Negative Edge Detection
• FSDEN: Transmit Frame Sync Data Enable
1: TSHR value is shifted out during the transmission of the Transmit Frame Sync signal.
0: The TX_DATA line is driven with the default value during the Transmit Frame Sync signal.
• FSOS: Transmit Frame Sync Output Selection
FSOS
Selected Transmit Frame Sync Signal
TX_FRAME_SYNC Pin
0
None
1
Negative Pulse
Output
2
Positive Pulse
Output
3
Driven Low during data transfer
Output
4
Driven High during data transfer
Output
5
Toggling at each start of data transfer
Output
Others
Reserved
Input-only
Undefined
• FSLEN: Transmit Frame Sync Length
This field defines the length of the Transmit Frame Sync signal and the number of bits shifted out from the TSHR register if
TFMR.FSDEN is equal to one.
Note: The four most significant bits for this field are located in the FSLENHI field.
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•
•
•
•
The pulse length is equal to ({FSLENHI,FSLEN} + 1) transmit clock periods, i.e., the pulse length can range from 1 to 256
transmit clock periods. If {FSLENHI,FSLEN} is zero, the Transmit Frame Sync signal is generated during one transmit clock
period.
DATNB: Data Number per Frame
This field defines the number of data words to be transferred after each transfer start, which is equal to (DATNB + 1).
MSBF: Most Significant Bit First
1: The most significant bit of the data register is shifted out first in the bit stream.
0: The lowest significant bit of the data register is shifted out first in the bit stream.
DATDEF: Data Default Value
This bit defines the level driven on the TX_DATA pin while out of transmission.
Note that if the pin is defined as multi-drive by the I/O Controller, the pin is enabled only if the TX_DATA output is one.
1: The level driven on the TX_DATA pin while out of transmission is one.
0: The level driven on the TX_DATA pin while out of transmission is zero.
DATLEN: Data Length
The bit stream contains (DATLEN + 1) data bits.
This field also defines the transfer size performed by the Peripheral DMA Controller assigned to the transmitter.
DATLEN
0
Transfer Size
Forbidden value (1-bit data length is not supported)
1-7
Data transfer are in bytes
8-15
Data transfer are in halfwords
Others
Data transfer are in words
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24.9.7
Name:
Receive Holding Register
RHR
Access Type:
Read-only
Offset:
0x20
Reset value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
RDAT[31:24]
23
22
21
20
RDAT[23:16]
15
14
13
12
RDAT[15:8]
7
6
5
4
RDAT[7:0]
• RDAT: Receive Data
Right aligned regardless of the number of data bits defined by the RFMR.DATLEN field.
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24.9.8
Name:
Transmit Holding Register
THR
Access Type:
Write-only
Offset:
0x24
Reset value:
0x00000000
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
TDAT[31:24]
23
22
21
20
TDAT[23:16]
15
14
13
12
TDAT[15:8]
7
6
5
4
TDAT[7:0]
• TDAT: Transmit Data
Right aligned regardless of the number of data bits defined by the TFMR.DATLEN field.
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24.9.9
Name:
Receive Synchronization Holding Register
RSHR
Access Type:
Read-only
Offset:
0x30
Reset value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
3
2
1
0
RSDAT[15:8]
7
6
5
4
RSDAT[7:0]
• RSDAT: Receive Synchronization Data
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24.9.10
Name:
Transmit Synchronization Holding Register
TSHR
Access Type:
Read/Write
Offset:
0x34
Reset value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
3
2
1
0
TSDAT[15:8]
7
6
5
4
TSDAT[7:0]
• TSDAT: Transmit Synchronization Data
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24.9.11
Name:
Receive Compare 0 Register
RC0R
Access Type:
Read/Write
Offset:
0x38
Reset value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
3
2
1
0
CP0[15:8]
7
6
5
4
CP0[7:0]
• CP0: Receive Compare Data 0
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24.9.12
Name:
Receive Compare 1 Register
RC1R
Access Type:
Read/Write
Offset:
0x3C
Reset value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
3
2
1
0
CP1[[15:8]
7
6
5
4
CP1[7:0]
• CP1: Receive Compare Data 1
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24.9.13
Name:
Status Register
SR
Access Type:
Read-only
Offset:
0x40
Reset value:
0x000000CC
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
RXEN
TXEN
15
14
13
12
11
10
9
8
-
-
-
-
RXSYN
TXSYN
CP1
CP0
7
6
5
4
3
2
1
0
-
-
OVRUN
RXRDY
-
-
TXEMPTY
TXRDY
• RXEN: Receive Enable
This bit is set when the CR.RXEN bit is written to one.
This bit is cleared when no data are being processed and the CR.RXDIS bit has been written to one.
• TXEN: Transmit Enable
This bit is set when the CR.TXEN bit is written to one.
This bit is cleared when no data are being processed and the CR.TXDIS bit has been written to one.
• RXSYN: Receive Sync
This bit is set when a Receive Sync has occurred.
This bit is cleared when the SR register is read.
• TXSYN: Transmit Sync
This bit is set when a Transmit Sync has occurred.
This bit is cleared when the SR register is read.
• CP1: Compare 1
This bit is set when compare 1 has occurred.
This bit is cleared when the SR register is read.
• CP0: Compare 0
This bit is set when compare 0 has occurred.
This bit is cleared when the SR register is read.
• OVRUN: Receive Overrun
This bit is set when data has been loaded in the RHR register while previous data has not yet been read.
This bit is cleared when the SR register is read.
• RXRDY: Receive Ready
This bit is set when data has been received and loaded in the RHR register.
This bit is cleared when the RHR register is empty.
• TXEMPTY: Transmit Empty
This bit is set when the last data written in the THR register has been loaded in the TSR register and last data loaded in the TSR
register has been transmitted.
This bit is cleared when data remains in the THR register or is currently transmitted from the TSR register.
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• TXRDY: Transmit Ready
This bit is set when the THR register is empty.
This bit is cleared when data has been loaded in the THR register and is waiting to be loaded in the TSR register.
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24.9.14
Name:
Interrupt Enable Register
IER
Access Type:
Write-only
Offset:
0x44
Reset value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
RXSYN
TXSYN
CP1
CP0
7
6
5
4
3
2
1
0
–
–
OVRUN
RXRDY
–
–
TXEMPTY
TXRDY
Writing a zero to a bit in this register has no effect.
Writing a one to a bit in this register will set the corresponding bit in IMR.
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24.9.15
Name:
Interrupt Disable Register
IDR
Access Type:
Write-only
Offset:
0x48
Reset value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
RXSYN
TXSYN
CP1
CP0
7
6
5
4
3
2
1
0
–
–
OVRUN
RXRDY
–
–
TXEMPTY
TXRDY
Writing a zero to a bit in this register has no effect.
Writing a one to a bit in this register will clear the corresponding bit in IMR.
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24.9.16
Name:
Interrupt Mask Register
IMR
Access Type:
Read-only
Offset:
0x4C
Reset value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
RXSYN
TXSYN
CP1
CP0
7
6
5
4
3
2
1
0
–
–
OVRUN
RXRDY
–
–
TXEMPTY
TXRDY
0: The corresponding interrupt is disabled.
1: The corresponding interrupt is enabled.
A bit in this register is cleared when the corresponding bit in IDR is written to one.
A bit in this register is set when the corresponding bit in IER is written to one.
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25. Universal Synchronous Asynchronous Receiver Transmitter (USART)
Rev.4.2.0.4
25.1
Features
• Programmable Baud Rate Generator
• 5- to 9-bit Full-duplex Synchronous or Asynchronous Serial Communications
•
•
•
•
•
•
•
25.2
– 1, 1.5 or 2 Stop Bits in Asynchronous Mode or 1 or 2 Stop Bits in Synchronous Mode
– Parity Generation and Error Detection
– Framing Error Detection, Overrun Error Detection
– MSB- or LSB-first
– Optional Break Generation and Detection
– By 8 or by 16 Over-sampling Receiver Frequency
– Optional Hardware Handshaking RTS-CTS
– Optional Modem Signal Management DTR-DSR-DCD-RI
– Receiver Time-out and Transmitter Timeguard
– Optional Multidrop Mode with Address Generation and Detection
RS485 with Driver Control Signal
ISO7816, T = 0 or T = 1 Protocols for Interfacing with Smart Cards
– NACK Handling, Error Counter with Repetition and Iteration Limit
IrDA Modulation and Demodulation
– Communication at up to 115.2 Kbps
SPI Mode
– Master or Slave
– Serial Clock Programmable Phase and Polarity
– SPI Serial Clock (CLK) Frequency up to Internal Clock Frequency CLK_USART/4
LIN Mode
– Compliant with LIN 1.3 and LIN 2.0 specifications
– Master or Slave
– Processing of frames with up to 256 data bytes
– Response Data length can be configurable or defined automatically by the Identifier
– Self synchronization in Slave node configuration
– Automatic processing and verification of the “Synch Break” and the “Synch Field”
– The “Synch Break” is detected even if it is partially superimposed with a data byte
– Automatic Identifier parity calculation/sending and verification
– Parity sending and verification can be disabled
– Automatic Checksum calculation/sending and verification
– Checksum sending and verification can be disabled
– Support both “Classic” and “Enhanced” checksum types
– Full LIN error checking and reporting
– Frame Slot Mode: the Master allocates slots to the scheduled frames automatically.
– Generation of the Wakeup signal
Test Modes
– Remote Loopback, Local Loopback, Automatic Echo
Supports Connection of Two Peripheral DMA Controller Channels (PDCA)
– Offers Buffer Transfer without Processor Intervention
Overview
The Universal Synchronous Asynchronous Receiver Transceiver (USART) provides one full
duplex universal synchronous asynchronous serial link. Data frame format is widely programma541
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ble (data length, parity, number of stop bits) to support a maximum of standards. The receiver
implements parity error, framing error and overrun error detection. The receiver time-out enables
handling variable-length frames and the transmitter timeguard facilitates communications with
slow remote devices. Multidrop communications are also supported through address bit handling in reception and transmission.
The USART features three test modes: remote loopback, local loopback and automatic echo.
The USART supports specific operating modes providing interfaces on RS485, LIN and SPI
buses, with ISO7816 T = 0 or T = 1 smart card slots, infrared transceivers and connection to
modem ports. The hardware handshaking feature enables an out-of-band flow control by automatic management of the pins RTS and CTS.
The USART supports the connection to the Peripheral DMA Controller, which enables data
transfers to the transmitter and from the receiver. The Peripheral DMA Controller provides
chained buffer management without any intervention of the processor.
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25.3
Block Diagram
Figure 25-1. USART Block Diagram
Peripheral DMA
Controller
Channel
Channel
USART
I/O
Controller
RXD
Receiver
RTS
INTC
USART
Interrupt
TXD
Transmitter
CTS
DTR
CLK_USART
Power
Manager
DIV
DSR
Modem
Signals
Control
CLK_USART/DIV
DCD
RI
CLK
BaudRate
Generator
User
Interface
Peripheral bus
Table 25-1.
SPI Operating Mode
PIN
USART
SPI Slave
SPI Master
RXD
RXD
MOSI
MISO
TXD
TXD
MISO
MOSI
RTS
RTS
–
CS
CTS
CTS
CS
–
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25.4
I/O Lines Description
Table 25-2.
I/O Lines Description
Name
Description
Type
Active Level
CLK
Serial Clock
I/O
TXD
Transmit Serial Data
or Master Out Slave In (MOSI) in SPI Master Mode
or Master In Slave Out (MISO) in SPI Slave Mode
Output
RXD
Receive Serial Data
or Master In Slave Out (MISO) in SPI Master Mode
or Master Out Slave In (MOSI) in SPI Slave Mode
Input
RI
Ring Indicator
Input
Low
DSR
Data Set Ready
Input
Low
DCD
Data Carrier Detect
Input
Low
DTR
Data Terminal Ready
Output
Low
CTS
Clear to Send
or Slave Select (NSS) in SPI Slave Mode
Input
Low
RTS
Request to Send
or Slave Select (NSS) in SPI Master Mode
Output
Low
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25.5
25.5.1
Product Dependencies
I/O Lines
The pins used for interfacing the USART may be multiplexed with the I/O Controller lines. The
programmer must first program the I/O Controller to assign the desired USART pins to their
peripheral function. If I/O lines of the USART are not used by the application, they can be used
for other purposes by the I/O Controller.
To prevent the TXD line from falling when the USART is disabled, the use of an internal pull up
is mandatory. If the hardware handshaking feature or Modem mode is used, the internal pull up
on TXD must also be enabled.
All the pins of the modems may or may not be implemented on the USART. On USARTs not
equipped with the corresponding pins, the associated control bits and statuses have no effect on
the behavior of the USART.
25.5.2
Clocks
The clock for the USART bus interface (CLK_USART) is generated by the Power Manager. This
clock is enabled at reset, and can be disabled in the Power Manager. It is recommended to disable the USART before disabling the clock, to avoid freezing the USART in an undefined state.
25.5.3
Interrupts
The USART interrupt request line is connected to the interrupt controller. Using the USART
interrupt requires the interrupt controller to be programmed first.
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25.6
Functional Description
The USART is capable of managing several types of serial synchronous or asynchronous
communications.
It supports the following communication modes:
• 5- to 9-bit full-duplex asynchronous serial communication
– MSB- or LSB-first
– 1, 1.5 or 2 stop bits
– Parity even, odd, marked, space or none
– By 8 or by 16 over-sampling receiver frequency
– Optional hardware handshaking
– Optional modem signals management
– Optional break management
– Optional multidrop serial communication
• High-speed 5- to 9-bit full-duplex synchronous serial communication
– MSB- or LSB-first
– 1 or 2 stop bits
– Parity even, odd, marked, space or none
– By 8 or by 16 over-sampling frequency
– Optional hardware handshaking
– Optional modem signals management
– Optional break management
– Optional multidrop serial communication
• RS485 with driver control signal
• ISO7816, T0 or T1 protocols for interfacing with smart cards
– NACK handling, error counter with repetition and iteration limit
• InfraRed IrDA Modulation and Demodulation
• SPI Mode
– Master or Slave
– Serial Clock Programmable Phase and Polarity
– SPI Serial Clock (CLK) Frequency up to Internal Clock Frequency CLK_USART/4
• LIN Mode
– Compliant with LIN 1.3 and LIN 2.0 specifications
– Master or Slave
– Processing of frames with up to 256 data bytes
– Response Data length can be configurable or defined automatically by the Identifier
– Self synchronization in Slave node configuration
– Automatic processing and verification of the “Synch Break” and the “Synch Field”
– The “Synch Break” is detected even if it is partially superimposed with a data byte
– Automatic Identifier parity calculation/sending and verification
– Parity sending and verification can be disabled
– Automatic Checksum calculation/sending and verification
– Checksum sending and verification can be disabled
– Support both “Classic” and “Enhanced” checksum types
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– Full LIN error checking and reporting
– Frame Slot Mode: the Master allocates slots to the scheduled frames automatically.
– Generation of the Wakeup signal
• Test modes
– Remote loopback, local loopback, automatic echo
25.6.1
Baud Rate Generator
The Baud Rate Generator provides the bit period clock named the Baud Rate Clock to both the
receiver and the transmitter.
The Baud Rate Generator clock source can be selected by setting the USCLKS field in the Mode
Register (MR) between:
• CLK_USART
• a division of CLK_USART, the divider being product dependent, but generally set to 8
• the external clock, available on the CLK pin
The Baud Rate Generator is based upon a 16-bit divider, which is programmed with the CD field
of the Baud Rate Generator Register (BRGR). If CD is programmed at 0, the Baud Rate Generator does not generate any clock. If CD is programmed at 1, the divider is bypassed and
becomes inactive.
If the external CLK clock is selected, the duration of the low and high levels of the signal provided on the CLK pin must be longer than a CLK_USART period. The frequency of the signal
provided on CLK must be at least 4.5 times lower than CLK_USART.
Figure 25-2. Baud Rate Generator
USCLKS
CLK_USART
CLK_USART/DIV
CLK
Reserved
CD
CD
0
1
2
CLK
16-bit Counter
FIDI
>1
3
1
0
SYNC
OVER
0
Sampling
Divider
0
0
BaudRate
Clock
1
1
SYNC
USCLKS= 3
25.6.1.1
Sampling
Clock
Baud Rate in Asynchronous Mode
If the USART is programmed to operate in asynchronous mode, the selected clock is first
divided by CD, which is field programmed in the Baud Rate Generator Register (BRGR). The
resulting clock is provided to the receiver as a sampling clock and then divided by 16 or 8,
depending on the programming of the OVER bit in MR.
If OVER is set to 1, the receiver sampling is 8 times higher than the baud rate clock. If OVER is
cleared, the sampling is performed at 16 times the baud rate clock.
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The following formula performs the calculation of the Baud Rate.
SelectedClock
Baudrate = -------------------------------------------( 8 ( 2 – Over )CD )
This gives a maximum baud rate of CLK_USART divided by 8, assuming that CLK_USART is
the highest possible clock and that OVER is programmed at 1.
25.6.1.2
Baud Rate Calculation Example
Table 25-3 shows calculations of CD to obtain a baud rate at 38400 bauds for different source
clock frequencies. This table also shows the actual resulting baud rate and the error.
Table 25-3.
Baud Rate Example (OVER = 0)
Source Clock
Expected Baud
Rate
MHz
Bit/s
3 686 400
38 400
6.00
6
38 400.00
0.00%
4 915 200
38 400
8.00
8
38 400.00
0.00%
5 000 000
38 400
8.14
8
39 062.50
1.70%
7 372 800
38 400
12.00
12
38 400.00
0.00%
8 000 000
38 400
13.02
13
38 461.54
0.16%
12 000 000
38 400
19.53
20
37 500.00
2.40%
12 288 000
38 400
20.00
20
38 400.00
0.00%
14 318 180
38 400
23.30
23
38 908.10
1.31%
14 745 600
38 400
24.00
24
38 400.00
0.00%
18 432 000
38 400
30.00
30
38 400.00
0.00%
24 000 000
38 400
39.06
39
38 461.54
0.16%
24 576 000
38 400
40.00
40
38 400.00
0.00%
25 000 000
38 400
40.69
40
38 109.76
0.76%
32 000 000
38 400
52.08
52
38 461.54
0.16%
32 768 000
38 400
53.33
53
38 641.51
0.63%
33 000 000
38 400
53.71
54
38 194.44
0.54%
40 000 000
38 400
65.10
65
38 461.54
0.16%
50 000 000
38 400
81.38
81
38 580.25
0.47%
60 000 000
38 400
97.66
98
38 265.31
0.35%
Calculation Result
CD
Actual Baud Rate
Error
Bit/s
The baud rate is calculated with the following formula:
BaudRate = ( CLKUSART ) ⁄ ( CD × 16 )
The baud rate error is calculated with the following formula. It is not recommended to work with
an error higher than 5%.
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ExpectedBaudRate
Error = 1 – ⎛ ---------------------------------------------------⎞
⎝ ActualBaudRate ⎠
25.6.1.3
Fractional Baud Rate in Asynchronous Mode
The Baud Rate generator previously defined is subject to the following limitation: the output frequency changes by only integer multiples of the reference frequency. An approach to this
problem is to integrate a fractional N clock generator that has a high resolution. The generator
architecture is modified to obtain Baud Rate changes by a fraction of the reference source clock.
This fractional part is programmed with the FP field in the Baud Rate Generator Register
(BRGR). If FP is not 0, the fractional part is activated. The resolution is one eighth of the clock
divider. This feature is only available when using USART normal mode. The fractional Baud
Rate is calculated using the following formula:
SelectedClock
Baudrate = ---------------------------------------------------------------⎛ 8 ( 2 – Over ) ⎛ CD + FP
-------⎞ ⎞
⎝
⎝
8 ⎠⎠
The modified architecture is presented below:
Figure 25-3. Fractional Baud Rate Generator
FP
USCLKS
CLK_USART
CLK_USART/DIV
CLK
Reserved
0
1
2
3
CD
Modulus
Control
FP
CD
16-bit Counter
glitch-free
logic
FIDI
>1
1
0
CLK
0
OVER
Sampling
Divider
0
SYNC
0
BaudRate
Clock
1
1
SYNC
USCLKS = 3
25.6.1.4
Sampling
Clock
Baud Rate in Synchronous Mode or SPI Mode
If the USART is programmed to operate in synchronous mode, the selected clock is simply
divided by the field CD in BRGR.
BaudRate = SelectedClock
-------------------------------------CD
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In synchronous mode, if the external clock is selected (USCLKS = 3), the clock is provided
directly by the signal on the USART CLK pin. No division is active. The value written in BRGR
has no effect. The external clock frequency must be at least 4.5 times lower than the system
clock.
When either the external clock CLK or the internal clock divided (CLK_USART/DIV) is selected,
the value programmed in CD must be even if the user has to ensure a 50:50 mark/space ratio on
the CLK pin. If the internal clock CLK_USART is selected, the Baud Rate Generator ensures a
50:50 duty cycle on the CLK pin, even if the value programmed in CD is odd.
25.6.1.5
Baud Rate in ISO 7816 Mode
The ISO7816 specification defines the bit rate with the following formula:
Di
B = ------ × f
Fi
where:
• B is the bit rate
• Di is the bit-rate adjustment factor
• Fi is the clock frequency division factor
• f is the ISO7816 clock frequency (Hz)
Di is a binary value encoded on a 4-bit field, named DI, as represented in Table 25-4.
Table 25-4.
Binary and Decimal Values for Di
DI field
0001
0010
0011
0100
0101
0110
1000
1001
1
2
4
8
16
32
12
20
Di (decimal)
Fi is a binary value encoded on a 4-bit field, named FI, as represented in Table 25-5.
Table 25-5.
Binary and Decimal Values for Fi
FI field
0000
0001
0010
0011
0100
0101
0110
1001
1010
1011
1100
1101
Fi (decimal
372
372
558
744
1116
1488
1860
512
768
1024
1536
2048
Table 25-6 shows the resulting Fi/Di Ratio, which is the ratio between the ISO7816 clock and the
baud rate clock.
Table 25-6.
Possible Values for the Fi/Di Ratio
Fi/Di
372
558
774
1116
1488
1806
512
768
1024
1536
2048
1
372
558
744
1116
1488
1860
512
768
1024
1536
2048
2
186
279
372
558
744
930
256
384
512
768
1024
4
93
139.5
186
279
372
465
128
192
256
384
512
8
46.5
69.75
93
139.5
186
232.5
64
96
128
192
256
16
23.25
34.87
46.5
69.75
93
116.2
32
48
64
96
128
32
11.62
17.43
23.25
34.87
46.5
58.13
16
24
32
48
64
12
31
46.5
62
93
124
155
42.66
64
85.33
128
170.6
20
18.6
27.9
37.2
55.8
74.4
93
25.6
38.4
51.2
76.8
102.4
If the USART is configured in ISO7816 Mode, the clock selected by the USCLKS field in the
Mode Register (MR) is first divided by the value programmed in the field CD in the Baud Rate
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Generator Register (BRGR). The resulting clock can be provided to the CLK pin to feed the
smart card clock inputs. This means that the CLKO bit can be set in MR.
This clock is then divided by the value programmed in the FI_DI_RATIO field in the FI_DI_Ratio
register (FIDI). This is performed by the Sampling Divider, which performs a division by up to
2047 in ISO7816 Mode. The non-integer values of the Fi/Di Ratio are not supported and the user
must program the FI_DI_RATIO field to a value as close as possible to the expected value.
The FI_DI_RATIO field resets to the value 0x174 (372 in decimal) and is the most common
divider between the ISO7816 clock and the bit rate (Fi = 372, Di = 1).
Figure 25-4 shows the relation between the Elementary Time Unit, corresponding to a bit time,
and the ISO 7816 clock.
Figure 25-4. Elementary Time Unit (ETU)
FI_DI_RATIO
ISO7816 Clock Cycles
ISO7816 Clock
on CLK
ISO7816 I/O Line
on TXD
1 ETU
25.6.2
Receiver and Transmitter Control
After reset, the receiver is disabled. The user must enable the receiver by setting the RXEN bit
in the Control Register (CR). However, the receiver registers can be programmed before the
receiver clock is enabled.
After reset, the transmitter is disabled. The user must enable it by setting the TXEN bit in the
Control Register (CR). However, the transmitter registers can be programmed before being
enabled.
The Receiver and the Transmitter can be enabled together or independently.
At any time, the software can perform a reset on the receiver or the transmitter of the USART by
setting the corresponding bit, RSTRX and RSTTX respectively, in the Control Register (CR).
The software resets clear the status flag and reset internal state machines but the user interface
configuration registers hold the value configured prior to software reset. Regardless of what the
receiver or the transmitter is performing, the communication is immediately stopped.
The user can also independently disable the receiver or the transmitter by setting RXDIS and
TXDIS respectively in CR. If the receiver is disabled during a character reception, the USART
waits until the end of reception of the current character, then the reception is stopped. If the
transmitter is disabled while it is operating, the USART waits the end of transmission of both the
current character and character being stored in the Transmit Holding Register (THR). If a timeguard is programmed, it is handled normally.
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25.6.3
25.6.3.1
Synchronous and Asynchronous Modes
Transmitter Operations
The transmitter performs the same in both synchronous and asynchronous operating modes
(SYNC = 0 or SYNC = 1). One start bit, up to 9 data bits, one optional parity bit and up to two
stop bits are successively shifted out on the TXD pin at each falling edge of the programmed
serial clock.
The number of data bits is selected by the CHRL field and the MODE 9 bit in the Mode Register
(MR). Nine bits are selected by setting the MODE 9 bit regardless of the CHRL field. The parity
bit is set according to the PAR field in MR. The even, odd, space, marked or none parity bit can
be configured. The MSBF field in MR configures which data bit is sent first. If written at 1, the
most significant bit is sent first. At 0, the less significant bit is sent first. The number of stop bits is
selected by the NBSTOP field in MR. The 1.5 stop bit is supported in asynchronous mode only.
Figure 25-5. Character Transmit
Example: 8-bit, Parity Enabled One Stop
Baud Rate
Clock
TXD
Start
Bit
D0
D1
D2
D3
D4
D5
D6
D7
Parity
Bit
Stop
Bit
The characters are sent by writing in the Transmit Holding Register (THR). The transmitter
reports two status bits in the Channel Status Register (CSR): TXRDY (Transmitter Ready),
which indicates that THR is empty and TXEMPTY, which indicates that all the characters written
in THR have been processed. When the current character processing is completed, the last
character written in THR is transferred into the Shift Register of the transmitter and THR
becomes empty, thus TXRDY rises.
Both TXRDY and TXEMPTY bits are low when the transmitter is disabled. Writing a character in
THR while TXRDY is low has no effect and the written character is lost.
Figure 25-6. Transmitter Status
Baud Rate
Clock
TXD
Start
D0
Bit
D1
D2
D3
D4
D5
D6
D7
Parity Stop Start
D0
Bit Bit Bit
D1
D2
D3
D4
D5
D6
D7
Parity Stop
Bit Bit
Write
THR
TXRDY
TXEMPTY
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25.6.3.2
Manchester Encoder
When the Manchester encoder is in use, characters transmitted through the USART are
encoded based on biphase Manchester II format. To enable this mode, set the MAN field in the
MR register to 1. Depending on polarity configuration, a logic level (zero or one), is transmitted
as a coded signal one-to-zero or zero-to-one. Thus, a transition always occurs at the midpoint of
each bit time. It consumes more bandwidth than the original NRZ signal (2x) but the receiver has
more error control since the expected input must show a change at the center of a bit cell. An
example of Manchester encoded sequence is: the byte 0xB1 or 10110001 encodes to 10 01 10
10 01 01 01 10, assuming the default polarity of the encoder. Figure 25-7 illustrates this coding
scheme.
Figure 25-7. NRZ to Manchester Encoding
NRZ
encoded
data
Manchester
encoded
data
1
0
1
1
0
0
0
1
Txd
The Manchester encoded character can also be encapsulated by adding both a configurable
preamble and a start frame delimiter pattern. Depending on the configuration, the preamble is a
training sequence, composed of a pre-defined pattern with a programmable length from 1 to 15
bit times. If the preamble length is set to 0, the preamble waveform is not generated prior to any
character. The preamble pattern is chosen among the following sequences: ALL_ONE,
ALL_ZERO, ONE_ZERO or ZERO_ONE, writing the field TX_PP in the MAN register, the field
TX_PL is used to configure the preamble length. Figure 25-8 illustrates and defines the valid
patterns. To improve flexibility, the encoding scheme can be configured using the TX_MPOL
field in the MAN register. If the TX_MPOL field is set to zero (default), a logic zero is encoded
with a zero-to-one transition and a logic one is encoded with a one-to-zero transition. If the
TX_MPOL field is set to one, a logic one is encoded with a one-to-zero transition and a logic
zero is encoded with a zero-to-one transition.
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Figure 25-8. Preamble Patterns, Default Polarity Assumed
Manchester
encoded
data
Txd
SFD
DATA
SFD
DATA
SFD
DATA
SFD
DATA
8 bit width "ALL_ONE" Preamble
Manchester
encoded
data
Txd
8 bit width "ALL_ZERO" Preamble
Manchester
encoded
data
Txd
8 bit width "ZERO_ONE" Preamble
Manchester
encoded
data
Txd
8 bit width "ONE_ZERO" Preamble
A start frame delimiter is to be configured using the ONEBIT field in the MR register. It consists
of a user-defined pattern that indicates the beginning of a valid data. Figure 25-9 illustrates
these patterns. If the start frame delimiter, also known as start bit, is one bit, (ONEBIT at 1), a
logic zero is Manchester encoded and indicates that a new character is being sent serially on the
line. If the start frame delimiter is a synchronization pattern also referred to as sync (ONEBIT at
0), a sequence of 3 bit times is sent serially on the line to indicate the start of a new character.
The sync waveform is in itself an invalid Manchester waveform as the transition occurs at the
middle of the second bit time. Two distinct sync patterns are used: the command sync and the
data sync. The command sync has a logic one level for one and a half bit times, then a transition
to logic zero for the second one and a half bit times. If the MODSYNC field in the MR register is
set to 1, the next character is a command. If it is set to 0, the next character is a data. When
direct memory access is used, the MODSYNC field can be immediately updated with a modified
character located in memory. To enable this mode, VAR_SYNC field in MR register must be set
to 1. In this case, the MODSYNC field in MR is bypassed and the sync configuration is held in
the TXSYNH in the THR register. The USART character format is modified and includes sync
information.
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Figure 25-9. Start Frame Delimiter
Preamble Length
is set to 0
SFD
Manchester
encoded
data
DATA
Txd
One bit start frame delimiter
SFD
Manchester
encoded
data
DATA
Txd
Command Sync
start frame delimiter
SFD
Manchester
encoded
data
DATA
Txd
Data Sync
start frame delimiter
Drift Compensation
Drift compensation is available only in 16X oversampling mode. An hardware recovery system
allows a larger clock drift. To enable the hardware system, the bit in the MAN register must be
set. If the RXD edge is one 16X clock cycle from the expected edge, this is considered as normal jitter and no corrective actions is taken. If the RXD event is between 4 and 2 clock cycles
before the expected edge, then the current period is shortened by one clock cycle. If the RXD
event is between 2 and 3 clock cycles after the expected edge, then the current period is lengthened by one clock cycle. These intervals are considered to be drift and so corrective actions are
automatically taken.
Figure 25-10. Bit Resynchronization
Oversampling
16x Clock
RXD
Sampling
point
Expected edge
Synchro.
Error
25.6.3.3
Synchro.
Jump
Tolerance
Sync
Jump
Synchro.
Error
Asynchronous Receiver
If the USART is programmed in asynchronous operating mode (SYNC = 0), the receiver oversamples the RXD input line. The oversampling is either 16 or 8 times the Baud Rate clock,
depending on the OVER bit in the Mode Register (MR).
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The receiver samples the RXD line. If the line is sampled during one half of a bit time at 0, a start
bit is detected and data, parity and stop bits are successively sampled on the bit rate clock.
If the oversampling is 16, (OVER at 0), a start is detected at the eighth sample at 0. Then, data
bits, parity bit and stop bit are sampled on each 16 sampling clock cycle. If the oversampling is 8
(OVER at 1), a start bit is detected at the fourth sample at 0. Then, data bits, parity bit and stop
bit are sampled on each 8 sampling clock cycle.
The number of data bits, first bit sent and parity mode are selected by the same fields and bits
as the transmitter, i.e. respectively CHRL, MODE9, MSBF and PAR. For the synchronization
mechanism only, the number of stop bits has no effect on the receiver as it considers only one
stop bit, regardless of the field NBSTOP, so that resynchronization between the receiver and the
transmitter can occur. Moreover, as soon as the stop bit is sampled, the receiver starts looking
for a new start bit so that resynchronization can also be accomplished when the transmitter is
operating with one stop bit.
Figure 25-11 and Figure 25-12 illustrate start detection and character reception when USART
operates in asynchronous mode.
Figure 25-11. Asynchronous Start Detection
Baud Rate
Clock
Sampling
Clock (x16)
RXD
Sampling
1
2
3
4
5
6
7
8
1
2
3
4
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16
D0
Sampling
Start
Detection
RXD
Sampling
1
2
3
4
5
6
7
0 1
Start
Rejection
Figure 25-12. Asynchronous Character Reception
Example: 8-bit, Parity Enabled
Baud Rate
Clock
RXD
Start
Detection
16
16
16
16
16
16
16
16
16
16
samples samples samples samples samples samples samples samples samples samples
D0
D1
D2
D3
D4
D5
D6
D7
Parity
Bit
Stop
Bit
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25.6.3.4
Manchester Decoder
When the MAN field in MR register is set to 1, the Manchester decoder is enabled. The decoder
performs both preamble and start frame delimiter detection. One input line is dedicated to Manchester encoded input data.
An optional preamble sequence can be defined, its length is user-defined and totally independent of the emitter side. Use RX_PL in MAN register to configure the length of the preamble
sequence. If the length is set to 0, no preamble is detected and the function is disabled. In addition, the polarity of the input stream is programmable with RX_MPOL field in MAN register.
Depending on the desired application the preamble pattern matching is to be defined via the
RX_PP field in MAN. See Figure 25-8 for available preamble patterns.
Unlike preamble, the start frame delimiter is shared between Manchester Encoder and Decoder.
So, if ONEBIT field is set to 1, only a zero encoded Manchester can be detected as a valid start
frame delimiter. If ONEBIT is set to 0, only a sync pattern is detected as a valid start frame
delimiter. Decoder operates by detecting transition on incoming stream. If RXD is sampled during one quarter of a bit time at zero, a start bit is detected. See Figure 25-13. The sample pulse
rejection mechanism applies.
Figure 25-13. Asynchronous Start Bit Detection
Sampling
Clock
(16 x)
Manchester
encoded
data
Txd
Start
Detection
1
2
3
4
The receiver is activated and starts Preamble and Frame Delimiter detection, sampling the data
at one quarter and then three quarters. If a valid preamble pattern or start frame delimiter is
detected, the receiver continues decoding with the same synchronization. If the stream does not
match a valid pattern or a valid start frame delimiter, the receiver re-synchronizes on the next
valid edge.The minimum time threshold to estimate the bit value is three quarters of a bit time.
If a valid preamble (if used) followed with a valid start frame delimiter is detected, the incoming
stream is decoded into NRZ data and passed to USART for processing. Figure 25-14 illustrates
Manchester pattern mismatch. When incoming data stream is passed to the USART, the
receiver is also able to detect Manchester code violation. A code violation is a lack of transition
in the middle of a bit cell. In this case, MANE flag in CSR register is raised. It is cleared by writing
the Control Register (CR) with the RSTSTA bit at 1. See Figure 25-15 for an example of Manchester error detection during data phase.
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Figure 25-14. Preamble Pattern Mismatch
Preamble Mismatch
Manchester coding error
Manchester
encoded
data
Preamble Mismatch
invalid pattern
SFD
Txd
DATA
Preamble Length is set to 8
Figure 25-15. Manchester Error Flag
Preamble Length
is set to 4
Elementary character bit time
SFD
Manchester
encoded
data
Txd
Entering USART character area
sampling points
Preamble subpacket
and Start Frame Delimiter
were successfully
decoded
Manchester
Coding Error
detected
When the start frame delimiter is a sync pattern (ONEBIT field at 0), both command and data
delimiter are supported. If a valid sync is detected, the received character is written as RXCHR
field in the RHR register and the RXSYNH is updated. RXCHR is set to 1 when the received
character is a command, and it is set to 0 if the received character is a data. This mechanism
alleviates and simplifies the direct memory access as the character contains its own sync field in
the same register.
As the decoder is setup to be used in unipolar mode, the first bit of the frame has to be a zero-toone transition.
25.6.3.5
Radio Interface: Manchester Encoded USART Application
This section describes low data rate RF transmission systems and their integration with a Manchester encoded USART. These systems are based on transmitter and receiver ICs that support
ASK and FSK modulation schemes.
The goal is to perform full duplex radio transmission of characters using two different frequency
carriers. See the configuration in Figure 25-16.
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Figure 25-16. Manchester Encoded Characters RF Transmission
Fup frequency Carrier
ASK/FSK
Upstream Receiver
Upstream
Emitter
LNA
VCO
RF filter
Demod
Serial
Configuration
Interface
control
Fdown frequency Carrier
bi-dir
line
Manchester
decoder
USART
Receiver
Manchester
encoder
USART
Emitter
ASK/FSK
downstream transmitter
Downstream
Receiver
PA
RF filter
Mod
VCO
control
The USART module is configured as a Manchester encoder/decoder. Looking at the downstream communication channel, Manchester encoded characters are serially sent to the RF
emitter. This may also include a user defined preamble and a start frame delimiter. Mostly, preamble is used in the RF receiver to distinguish between a valid data from a transmitter and
signals due to noise. The Manchester stream is then modulated. See Figure 25-17 for an example of ASK modulation scheme. When a logic one is sent to the ASK modulator, the power
amplifier, referred to as PA, is enabled and transmits an RF signal at downstream frequency.
When a logic zero is transmitted, the RF signal is turned off. If the FSK modulator is activated,
two different frequencies are used to transmit data. When a logic 1 is sent, the modulator outputs an RF signal at frequency F0 and switches to F1 if the data sent is a 0. See Figure 25-18.
From the receiver side, another carrier frequency is used. The RF receiver performs a bit check
operation examining demodulated data stream. If a valid pattern is detected, the receiver
switches to receiving mode. The demodulated stream is sent to the Manchester decoder.
Because of bit checking inside RF IC, the data transferred to the microcontroller is reduced by a
user-defined number of bits. The Manchester preamble length is to be defined in accordance
with the RF IC configuration.
Figure 25-17. ASK Modulator Output
1
0
0
1
NRZ stream
Manchester
encoded
data
default polarity
unipolar output
Txd
ASK Modulator
Output
Uptstream Frequency F0
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Figure 25-18. FSK Modulator Output
1
0
0
1
NRZ stream
Manchester
encoded
data
default polarity
unipolar output
Txd
FSK Modulator
Output
Uptstream Frequencies
[F0, F0+offset]
25.6.3.6
Synchronous Receiver
In synchronous mode (SYNC = 1), the receiver samples the RXD signal on each rising edge of
the Baud Rate Clock. If a low level is detected, it is considered as a start. All data bits, the parity
bit and the stop bits are sampled and the receiver waits for the next start bit. Synchronous mode
operations provide a high speed transfer capability.
Configuration fields and bits are the same as in asynchronous mode.
Figure 25-19 illustrates a character reception in synchronous mode.
Figure 25-19. Synchronous Mode Character Reception
Example: 8-bit, Parity Enabled 1 Stop
Baud Rate
Clock
RXD
Sampling
Start
D0
D1
D2
D3
D4
D5
D6
Stop Bit
D7
Parity Bit
25.6.3.7
Receiver Operations
When a character reception is completed, it is transferred to the Receive Holding Register
(RHR) and the RXRDY bit in the Status Register (CSR) rises. If a character is completed while
the RXRDY is set, the OVRE (Overrun Error) bit is set. The last character is transferred into
RHR and overwrites the previous one. The OVRE bit is cleared by writing the Control Register
(CR) with the RSTSTA (Reset Status) bit at 1.
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Figure 25-20. Receiver Status
Baud Rate
Clock
RXD
Start
D0
Bit
D1
D2
D3
D4
D5
D6
D7
Parity Stop Start
D0
Bit Bit Bit
D1
D2
D3
D4
D5
D6
D7
Parity Stop
Bit Bit
RSTSTA = 1
Write
CR
Read
RHR
RXRDY
OVRE
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25.6.3.8
Parity
The USART supports five parity modes selected by programming the PAR field in the Mode
Register (MR). The PAR field also enables the Multidrop mode, see ”Multidrop Mode” on page
563. Even and odd parity bit generation and error detection are supported.
If even parity is selected, the parity generator of the transmitter drives the parity bit at 0 if a number of 1s in the character data bit is even, and at 1 if the number of 1s is odd. Accordingly, the
receiver parity checker counts the number of received 1s and reports a parity error if the sampled parity bit does not correspond. If odd parity is selected, the parity generator of the
transmitter drives the parity bit at 1 if a number of 1s in the character data bit is even, and at 0 if
the number of 1s is odd. Accordingly, the receiver parity checker counts the number of received
1s and reports a parity error if the sampled parity bit does not correspond. If the mark parity is
used, the parity generator of the transmitter drives the parity bit at 1 for all characters. The
receiver parity checker reports an error if the parity bit is sampled at 0. If the space parity is
used, the parity generator of the transmitter drives the parity bit at 0 for all characters. The
receiver parity checker reports an error if the parity bit is sampled at 1. If parity is disabled, the
transmitter does not generate any parity bit and the receiver does not report any parity error.
Table 25-7 shows an example of the parity bit for the character 0x41 (character ASCII “A”)
depending on the configuration of the USART. Because there are two bits at 1, 1 bit is added
when a parity is odd, or 0 is added when a parity is even.
Table 25-7.
Parity Bit Examples
Character
Hexa
Binary
Parity Bit
Parity Mode
A
0x41
0100 0001
1
Odd
A
0x41
0100 0001
0
Even
A
0x41
0100 0001
1
Mark
A
0x41
0100 0001
0
Space
A
0x41
0100 0001
None
None
When the receiver detects a parity error, it sets the PARE (Parity Error) bit in the Channel Status
Register (CSR). The PARE bit can be cleared by writing the Control Register (CR) with the RSTSTA bit at 1. Figure 25-21 illustrates the parity bit status setting and clearing.
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Figure 25-21. Parity Error
Baud Rate
Clock
RXD
Start
D0
Bit
D1
D2
D3
D4
D5
D6
D7
Bad Stop
Parity Bit
Bit
RSTSTA = 1
Write
CR
PARE
RXRDY
25.6.3.9
Multidrop Mode
If the PAR field in the Mode Register (MR) is programmed to the value 0x6 or 0x07, the USART
runs in Multidrop Mode. This mode differentiates the data characters and the address characters. Data is transmitted with the parity bit at 0 and addresses are transmitted with the parity bit
at 1.
If the USART is configured in multidrop mode, the receiver sets the PARE parity error bit when
the parity bit is high and the transmitter is able to send a character with the parity bit high when
the Control Register is written with the SENDA bit at 1.
To handle parity error, the PARE bit is cleared when the Control Register is written with the bit
RSTSTA at 1.
The transmitter sends an address byte (parity bit set) when SENDA is written to CR. In this case,
the next byte written to THR is transmitted as an address. Any character written in THR without
having written the command SENDA is transmitted normally with the parity at 0.
25.6.3.10
Transmitter Timeguard
The timeguard feature enables the USART interface with slow remote devices.
The timeguard function enables the transmitter to insert an idle state on the TXD line between
two characters. This idle state actually acts as a long stop bit.
The duration of the idle state is programmed in the TG field of the Transmitter Timeguard Register (TTGR). When this field is programmed at zero no timeguard is generated. Otherwise, the
transmitter holds a high level on TXD after each transmitted byte during the number of bit periods programmed in TG in addition to the number of stop bits.
As illustrated in Figure 25-22, the behavior of TXRDY and TXEMPTY status bits is modified by
the programming of a timeguard. TXRDY rises only when the start bit of the next character is
sent, and thus remains at 0 during the timeguard transmission if a character has been written in
THR. TXEMPTY remains low until the timeguard transmission is completed as the timeguard is
part of the current character being transmitted.
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Figure 25-22. Timeguard Operations
TG = 4
TG = 4
Baud Rate
Clock
TXD
Start
D0
Bit
D1
D2
D3
D4
D5
D6
D7
Parity Stop
Bit Bit
Start
D0
Bit
D1
D2
D3
D4
D5
D6
D7
Parity Stop
Bit Bit
Write
THR
TXRDY
TXEMPTY
Table 25-8 indicates the maximum length of a timeguard period that the transmitter can handle
in relation to the function of the Baud Rate.
Table 25-8.
25.6.3.11
Maximum Timeguard Length Depending on Baud Rate
Baud Rate
Bit time
Timeguard
Bit/sec
µs
ms
1 200
833
212.50
9 600
104
26.56
14400
69.4
17.71
19200
52.1
13.28
28800
34.7
8.85
33400
29.9
7.63
56000
17.9
4.55
57600
17.4
4.43
115200
8.7
2.21
Receiver Time-out
The Receiver Time-out provides support in handling variable-length frames. This feature detects
an idle condition on the RXD line. When a time-out is detected, the bit TIMEOUT in the Channel
Status Register (CSR) rises and can generate an interrupt, thus indicating to the driver an end of
frame.
The time-out delay period (during which the receiver waits for a new character) is programmed
in the TO field of the Receiver Time-out Register (RTOR). If the TO field is programmed at 0, the
Receiver Time-out is disabled and no time-out is detected. The TIMEOUT bit in CSR remains at
0. Otherwise, the receiver loads a counter with the value programmed in TO. This counter is
decremented at each bit period and reloaded each time a new character is received. If the counter reaches 0, the TIMEOUT bit in the Status Register rises. Then, the user can either:
• Stop the counter clock until a new character is received. This is performed by writing the
Control Register (CR) with the STTTO (Start Time-out) bit at 1. In this case, the idle state on
RXD before a new character is received will not provide a time-out. This prevents having to
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handle an interrupt before a character is received and allows waiting for the next idle state on
RXD after a frame is received.
• Obtain an interrupt while no character is received. This is performed by writing CR with the
RETTO (Reload and Start Time-out) bit at 1. If RETTO is performed, the counter starts
counting down immediately from the value TO. This enables generation of a periodic interrupt
so that a user time-out can be handled, for example when no key is pressed on a keyboard.
If STTTO is performed, the counter clock is stopped until a first character is received. The idle
state on RXD before the start of the frame does not provide a time-out. This prevents having to
obtain a periodic interrupt and enables a wait of the end of frame when the idle state on RXD is
detected.
If RETTO is performed, the counter starts counting down immediately from the value TO. This
enables generation of a periodic interrupt so that a user time-out can be handled, for example
when no key is pressed on a keyboard.
Figure 25-23 shows the block diagram of the Receiver Time-out feature.
Figure 25-23. Receiver Time-out Block Diagram
TO
Baud Rate
Clock
1
D
Q
Clock
16-bit Time-out
Counter
16-bit
Value
=
STTTO
Character
Received
Load
Clear
TIMEOUT
0
RETTO
Table 25-9 gives the maximum time-out period for some standard baud rates.
Table 25-9.
Maximum Time-out Period
Baud Rate
Bit Time
Time-out
bit/sec
µs
ms
600
1 667
109 225
1 200
833
54 613
2 400
417
27 306
4 800
208
13 653
9 600
104
6 827
14400
69
4 551
19200
52
3 413
28800
35
2 276
33400
30
1 962
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Table 25-9.
25.6.3.12
Maximum Time-out Period (Continued)
Baud Rate
Bit Time
Time-out
56000
18
1 170
57600
17
1 138
200000
5
328
Framing Error
The receiver is capable of detecting framing errors. A framing error happens when the stop bit of
a received character is detected at level 0. This can occur if the receiver and the transmitter are
fully desynchronized.
A framing error is reported on the FRAME bit of the Channel Status Register (CSR). The
FRAME bit is asserted in the middle of the stop bit as soon as the framing error is detected. It is
cleared by writing the Control Register (CR) with the RSTSTA bit at 1.
Figure 25-24. Framing Error Status
Baud Rate
Clock
RXD
Start
D0
Bit
D1
D2
D3
D4
D5
D6
D7
Parity Stop
Bit Bit
RSTSTA = 1
Write
CR
FRAME
RXRDY
25.6.3.13
Transmit Break
The user can request the transmitter to generate a break condition on the TXD line. A break condition drives the TXD line low during at least one complete character. It appears the same as a
0x00 character sent with the parity and the stop bits at 0. However, the transmitter holds the
TXD line at least during one character until the user requests the break condition to be removed.
A break is transmitted by writing the Control Register (CR) with the STTBRK bit at 1. This can be
performed at any time, either while the transmitter is empty (no character in either the Shift Register or in THR) or when a character is being transmitted. If a break is requested while a
character is being shifted out, the character is first completed before the TXD line is held low.
Once STTBRK command is requested further STTBRK commands are ignored until the end of
the break is completed.
The break condition is removed by writing CR with the STPBRK bit at 1. If the STPBRK is
requested before the end of the minimum break duration (one character, including start, data,
parity and stop bits), the transmitter ensures that the break condition completes.
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The transmitter considers the break as though it is a character, i.e. the STTBRK and STPBRK
commands are taken into account only if the TXRDY bit in CSR is at 1 and the start of the break
condition clears the TXRDY and TXEMPTY bits as if a character is processed.
Writing CR with the both STTBRK and STPBRK bits at 1 can lead to an unpredictable result. All
STPBRK commands requested without a previous STTBRK command are ignored. A byte written into the Transmit Holding Register while a break is pending, but not started, is ignored.
After the break condition, the transmitter returns the TXD line to 1 for a minimum of 12 bit times.
Thus, the transmitter ensures that the remote receiver detects correctly the end of break and the
start of the next character. If the timeguard is programmed with a value higher than 12, the TXD
line is held high for the timeguard period.
After holding the TXD line for this period, the transmitter resumes normal operations.
Figure 25-25 illustrates the effect of both the Start Break (STTBRK) and Stop Break (STPBRK)
commands on the TXD line.
Figure 25-25. Break Transmission
Baud Rate
Clock
TXD
Start
D0
Bit
D1
D2
D3
D4
D5
STTBRK = 1
D6
D7
Parity Stop
Bit Bit
Break Transmission
End of Break
STPBRK = 1
Write
CR
TXRDY
TXEMPTY
25.6.3.14
Receive Break
The receiver detects a break condition when all data, parity and stop bits are low. This corresponds to detecting a framing error with data at 0x00, but FRAME remains low.
When the low stop bit is detected, the receiver asserts the RXBRK bit in CSR. This bit may be
cleared by writing the Control Register (CR) with the bit RSTSTA at 1.
An end of receive break is detected by a high level for at least 2/16 of a bit period in asynchronous operating mode or one sample at high level in synchronous operating mode. The end of
break detection also asserts the RXBRK bit.
25.6.3.15
Hardware Handshaking
The USART features a hardware handshaking out-of-band flow control. The RTS and CTS pins
are used to connect with the remote device, as shown in Figure 25-26.
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Figure 25-26. Connection with a Remote Device for Hardware Handshaking
USART
Remote
Device
TXD
RXD
RXD
TXD
CTS
RTS
RTS
CTS
Setting the USART to operate with hardware handshaking is performed by writing the MODE
field in the Mode Register (MR) to the value 0x2.
The USART behavior when hardware handshaking is enabled is the same as the behavior in
standard synchronous or asynchronous mode, except that the receiver drives the RTS pin as
described below and the level on the CTS pin modifies the behavior of the transmitter as
described below. Using this mode requires using the Peripheral DMA Controller channel for
reception. The transmitter can handle hardware handshaking in any case.
Figure 25-27 shows how the receiver operates if hardware handshaking is enabled. The RTS
pin is driven high if the receiver is disabled and if the status RXBUFF (Receive Buffer Full) coming from the Peripheral DMA Controller channel is high. Normally, the remote device does not
start transmitting while its CTS pin (driven by RTS) is high. As soon as the Receiver is enabled,
the RTS falls, indicating to the remote device that it can start transmitting. Defining a new buffer
to the Peripheral DMA Controller clears the status bit RXBUFF and, as a result, asserts the pin
RTS low.
Figure 25-27. Receiver Behavior when Operating with Hardware Handshaking
RXD
RXEN = 1
RXDIS = 1
Write
CR
RTS
RXBUFF
Figure 25-28 shows how the transmitter operates if hardware handshaking is enabled. The CTS
pin disables the transmitter. If a character is being processing, the transmitter is disabled only
after the completion of the current character and transmission of the next character happens as
soon as the pin CTS falls.
Figure 25-28. Transmitter Behavior when Operating with Hardware Handshaking
CTS
TXD
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25.6.4
ISO7816 Mode
The USART features an ISO7816-compatible operating mode. This mode permits interfacing
with smart cards and Security Access Modules (SAM) communicating through an ISO7816 link.
Both T = 0 and T = 1 protocols defined by the ISO7816 specification are supported.
Setting the USART in ISO7816 mode is performed by writing the MODE field in the Mode Register (MR) to the value 0x4 for protocol T = 0 and to the value 0x6 for protocol T = 1.
25.6.4.1
ISO7816 Mode Overview
The ISO7816 is a half duplex communication on only one bidirectional line. The baud rate is
determined by a division of the clock provided to the remote device (see ”Baud Rate Generator”
on page 547).
The USART connects to a smart card as shown in Figure 25-29. The TXD line becomes bidirectional and the Baud Rate Generator feeds the ISO7816 clock on the CLK pin. As the TXD pin
becomes bidirectional, its output remains driven by the output of the transmitter but only when
the transmitter is active while its input is directed to the input of the receiver. The USART is considered as the master of the communication as it generates the clock.
Figure 25-29. Connection of a Smart Card to the USART
USART
CLK
TXD
CLK
I/O
Smart
Card
When operating in ISO7816, either in T = 0 or T = 1 modes, the character format is fixed. The
configuration is 8 data bits, even parity and 1 or 2 stop bits, regardless of the values programmed in the CHRL, MODE9, PAR and CHMODE fields. MSBF can be used to transmit LSB
or MSB first. Parity Bit (PAR) can be used to transmit in normal or inverse mode. Refer to ”Mode
Register” on page 605 and ”PAR: Parity Type” on page 606.
The USART cannot operate concurrently in both receiver and transmitter modes as the communication is unidirectional at a time. It has to be configured according to the required mode by
enabling or disabling either the receiver or the transmitter as desired. Enabling both the receiver
and the transmitter at the same time in ISO7816 mode may lead to unpredictable results.
The ISO7816 specification defines an inverse transmission format. Data bits of the character
must be transmitted on the I/O line at their negative value. The USART does not support this format and the user has to perform an exclusive OR on the data before writing it in the Transmit
Holding Register (THR) or after reading it in the Receive Holding Register (RHR).
25.6.4.2
Protocol T = 0
In T = 0 protocol, a character is made up of one start bit, eight data bits, one parity bit and one
guard time, which lasts two bit times. The transmitter shifts out the bits and does not drive the
I/O line during the guard time.
If no parity error is detected, the I/O line remains at 1 during the guard time and the transmitter
can continue with the transmission of the next character, as shown in Figure 25-30.
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If a parity error is detected by the receiver, it drives the I/O line at 0 during the guard time, as
shown in Figure 25-31. This error bit is also named NACK, for Non Acknowledge. In this case,
the character lasts 1 bit time more, as the guard time length is the same and is added to the
error bit time which lasts 1 bit time.
When the USART is the receiver and it detects an error, it does not load the erroneous character
in the Receive Holding Register (RHR). It appropriately sets the PARE bit in the Status Register
(SR) so that the software can handle the error.
Figure 25-30. T = 0 Protocol without Parity Error
Baud Rate
Clock
RXD
Start
Bit
D0
D2
D1
D4
D3
D5
D6
D7
Parity Guard Guard Next
Bit Time 1 Time 2 Start
Bit
Figure 25-31. T = 0 Protocol with Parity Error
Baud Rate
Clock
Error
I/O
Start
Bit
D0
D1
D2
D3
D4
D5
D6
D7
Parity Guard
Bit Time 1
Guard Start
Time 2 Bit
D0
D1
Repetition
25.6.4.3
Receive Error Counter
The USART receiver also records the total number of errors. This can be read in the Number of
Error (NER) register. The NB_ERRORS field can record up to 255 errors. Reading NER automatically clears the NB_ERRORS field.
25.6.4.4
Receive NACK Inhibit
The USART can also be configured to inhibit an error. This can be achieved by setting the
INACK bit in the Mode Register (MR). If INACK is at 1, no error signal is driven on the I/O line
even if a parity bit is detected.
Moreover, if INACK is set, the erroneous received character is stored in the Receive Holding
Register, as if no error occurred. However, the RXRDY bit does raise.
25.6.4.5
Transmit Character Repetition
When the USART is transmitting a character and gets a NACK, it can automatically repeat the
character before moving on to the next one. Repetition is enabled by writing the
MAX_ITERATION field in the Mode Register (MR) at a value higher than 0. Each character can
be transmitted up to eight times; the first transmission plus seven repetitions.
If MAX_ITERATION does not equal zero, the USART repeats the character as many times as
the value loaded in MAX_ITERATION.
When the USART repetition number reaches MAX_ITERATION, the ITERATION bit is set in the
Channel Status Register (CSR). If the repetition of the character is acknowledged by the
receiver, the repetitions are stopped and the iteration counter is cleared.
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The ITERATION bit in CSR can be cleared by writing the Control Register with the RSIT bit at 1.
25.6.4.6
Disable Successive Receive NACK
The receiver can limit the number of successive NACKs sent back to the remote transmitter.
This is programmed by setting the bit DSNACK in the Mode Register (MR). The maximum number of NACK transmitted is programmed in the MAX_ITERATION field. As soon as
MAX_ITERATION is reached, the character is considered as correct, an acknowledge is sent on
the line and the ITERATION bit in the Channel Status Register is set.
25.6.4.7
Protocol T = 1
When operating in ISO7816 protocol T = 1, the transmission is similar to an asynchronous format with only one stop bit. The parity is generated when transmitting and checked when
receiving. Parity error detection sets the PARE bit in the Channel Status Register (CSR).
25.6.5
IrDA Mode
The USART features an IrDA mode supplying half-duplex point-to-point wireless communication. It embeds the modulator and demodulator which allows a glueless connection to the
infrared transceivers, as shown in Figure 25-32. The modulator and demodulator are compliant
with the IrDA specification version 1.1 and support data transfer speeds ranging from 2.4 Kb/s to
115.2 Kb/s.
The USART IrDA mode is enabled by setting the MODE field in the Mode Register (MR) to the
value 0x8. The IrDA Filter Register (IFR) allows configuring the demodulator filter. The USART
transmitter and receiver operate in a normal asynchronous mode and all parameters are accessible (except those fixed by IrDA specification : one start bit , 8 data bits and one stop bit). Note
that the modulator and the demodulator are activated.
Figure 25-32. Connection to IrDA Transceivers
USART
IrDA
Transceivers
Receiver
Demodulator
RXD
Transmitter
Modulator
TXD
RX
TX
The receiver and the transmitter must be enabled or disabled according to the direction of the
transmission to be managed.
To receive IrDA signals, the following needs to be done:
• Disable TX and Enable RX
• Configure the TXD pin as I/O and set it as an output at 0 (to avoid LED emission). Disable the
internal pull-up (better for power consumption).
• Receive data
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25.6.5.1
IrDA Modulation
For baud rates up to and including 115.2 Kbits/sec, the RZI modulation scheme is used. “0” is
represented by a light pulse of 3/16th of a bit time. Some examples of signal pulse duration are
shown in Table 25-10.
Table 25-10. IrDA Pulse Duration
Baud Rate
Pulse Duration (3/16)
2.4 Kb/s
78.13 µs
9.6 Kb/s
19.53 µs
19.2 Kb/s
9.77 µs
38.4 Kb/s
4.88 µs
57.6 Kb/s
3.26 µs
115.2 Kb/s
1.63 µs
Figure 25-33 shows an example of character transmission.
Figure 25-33. IrDA Modulation
Start
Bit
Transmitter
Output
0
Stop
Bit
Data Bits
1
0
1
0
0
1
1
0
1
TXD
3
16 Bit Period
Bit Period
25.6.5.2
IrDA Baud Rate
Table 25-11 gives some examples of CD values, baud rate error and pulse duration. Note that
the requirement on the maximum acceptable error of ±1.87% must be met.
Table 25-11. IrDA Baud Rate Error
Peripheral Clock
Baud Rate
CD
Baud Rate Error
Pulse Time
3 686 400
115 200
2
0.00%
1.63
20 000 000
115 200
11
1.38%
1.63
32 768 000
115 200
18
1.25%
1.63
40 000 000
115 200
22
1.38%
1.63
3 686 400
57 600
4
0.00%
3.26
20 000 000
57 600
22
1.38%
3.26
32 768 000
57 600
36
1.25%
3.26
40 000 000
57 600
43
0.93%
3.26
3 686 400
38 400
6
0.00%
4.88
20 000 000
38 400
33
1.38%
4.88
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Table 25-11. IrDA Baud Rate Error (Continued)
Peripheral Clock
25.6.5.3
Baud Rate
CD
Baud Rate Error
Pulse Time
32 768 000
38 400
53
0.63%
4.88
40 000 000
38 400
65
0.16%
4.88
3 686 400
19 200
12
0.00%
9.77
20 000 000
19 200
65
0.16%
9.77
32 768 000
19 200
107
0.31%
9.77
40 000 000
19 200
130
0.16%
9.77
3 686 400
9 600
24
0.00%
19.53
20 000 000
9 600
130
0.16%
19.53
32 768 000
9 600
213
0.16%
19.53
40 000 000
9 600
260
0.16%
19.53
3 686 400
2 400
96
0.00%
78.13
20 000 000
2 400
521
0.03%
78.13
32 768 000
2 400
853
0.04%
78.13
IrDA Demodulator
The demodulator is based on the IrDA Receive filter comprised of an 8-bit down counter which is
loaded with the value programmed in IFR. When a falling edge is detected on the RXD pin, the
Filter Counter starts counting down at the CLK_USART speed. If a rising edge is detected on the
RXD pin, the counter stops and is reloaded with IFR. If no rising edge is detected when the
counter reaches 0, the input of the receiver is driven low during one bit time.
Figure 25-34 illustrates the operations of the IrDA demodulator.
Figure 25-34. IrDA Demodulator Operations
CLK_USART
RXD
Counter
Value
Receiver
Input
6
5
4
3
2
6
6
5
4
3
2
1
0
Pulse
Accepted
Pulse
Rejected
Driven Low During 16 Baud Rate Clock Cycles
As the IrDA mode uses the same logic as the ISO7816, note that the FI_DI_RATIO field in FIDI
must be set to a value higher than 0 in order to assure IrDA communications operate correctly.
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25.6.6
RS485 Mode
The USART features the RS485 mode to enable line driver control. While operating in RS485
mode, the USART behaves as though in asynchronous or synchronous mode and configuration
of all the parameters is possible. The difference is that the RTS pin is driven high when the
transmitter is operating. The behavior of the RTS pin is controlled by the TXEMPTY bit. A typical
connection of the USART to a RS485 bus is shown in Figure 25-35.
Figure 25-35. Typical Connection to a RS485 Bus
USART
RXD
Differential
Bus
TXD
RTS
The USART is set in RS485 mode by programming the MODE field in the Mode Register (MR)
to the value 0x1.
The RTS pin is at a level inverse to the TXEMPTY bit. Significantly, the RTS pin remains high
when a timeguard is programmed so that the line can remain driven after the last character completion. Figure 25-36 gives an example of the RTS waveform during a character transmission
when the timeguard is enabled.
Figure 25-36. Example of RTS Drive with Timeguard
TG = 4
Baud Rate
Clock
TXD
Start
D0
Bit
D1
D2
D3
D4
D5
D6
D7
Parity Stop
Bit Bit
Write
THR
TXRDY
TXEMPTY
RTS
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25.6.7
Modem Mode
The USART features modem mode, which enables control of the signals: DTR (Data Terminal
Ready), DSR (Data Set Ready), RTS (Request to Send), CTS (Clear to Send), DCD (Data Carrier Detect) and RI (Ring Indicator). While operating in modem mode, the USART behaves as a
DTE (Data Terminal Equipment) as it drives DTR and RTS and can detect level change on DSR,
DCD, CTS and RI.
Setting the USART in modem mode is performed by writing the MODE field in the Mode Register (MR) to the value 0x3. While operating in modem mode the USART behaves as though in
asynchronous mode and all the parameter configurations are available.
Table 25-12 gives the correspondence of the USART signals with modem connection standards.
Table 25-12. Circuit References
USART Pin
V24
CCITT
Direction
TXD
2
103
From terminal to modem
RTS
4
105
From terminal to modem
DTR
20
108.2
From terminal to modem
RXD
3
104
From modem to terminal
CTS
5
106
From terminal to modem
DSR
6
107
From terminal to modem
DCD
8
109
From terminal to modem
RI
22
125
From terminal to modem
The control of the DTR output pin is performed by writing the Control Register (CR) with the
DTRDIS and DTREN bits respectively at 1. The disable command forces the corresponding pin
to its inactive level, i.e. high. The enable command forces the corresponding pin to its active
level, i.e. low. RTS output pin is automatically controlled in this mode
The level changes are detected on the RI, DSR, DCD and CTS pins. If an input change is
detected, the RIIC, DSRIC, DCDIC and CTSIC bits in the Channel Status Register (CSR) are set
respectively and can trigger an interrupt. The status is automatically cleared when CSR is read.
Furthermore, the CTS automatically disables the transmitter when it is detected at its inactive
state. If a character is being transmitted when the CTS rises, the character transmission is completed before the transmitter is actually disabled.
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25.6.8
SPI Mode
The Serial Peripheral Interface (SPI) Mode is a synchronous serial data link that provides communication with external devices in Master or Slave Mode. It also enables communication
between processors if an external processor is connected to the system.
The Serial Peripheral Interface is essentially a shift register that serially transmits data bits to
other SPIs. During a data transfer, one SPI system acts as the “master” which controls the data
flow, while the other devices act as “slaves'' which have data shifted into and out by the master.
Different CPUs can take turns being masters and one master may simultaneously shift data into
multiple slaves. (Multiple Master Protocol is the opposite of Single Master Protocol, where one
CPU is always the master while all of the others are always slaves.) However, only one slave
may drive its output to write data back to the master at any given time.
A slave device is selected when its NSS signal is asserted by the master. The USART in SPI
Master mode can address only one SPI Slave because it can generate only one NSS signal.
The SPI system consists of two data lines and two control lines:
• Master Out Slave In (MOSI): This data line supplies the output data from the master shifted
into the input of the slave.
• Master In Slave Out (MISO): This data line supplies the output data from a slave to the input
of the master.
• Serial Clock (CLK): This control line is driven by the master and regulates the flow of the data
bits. The master may transmit data at a variety of baud rates. The CLK line cycles once for
each bit that is transmitted.
• Slave Select (NSS): This control line allows the master to select or deselect the slave.
25.6.8.1
Modes of Operation
The USART can operate in Master Mode or in Slave Mode.
Operation in SPI Master Mode is programmed by writing at 0xE the MODE field in the Mode
Register. In this case the SPI lines must be connected as described below:
• the MOSI line is driven by the output pin TXD
• the MISO line drives the input pin RXD
• the CLK line is driven by the output pin CLK
• the NSS line is driven by the output pin RTS
Operation in SPI Slave Mode is programmed by writing at 0xF the MODE field in the Mode Register. In this case the SPI lines must be connected as described below:
• the MOSI line drives the input pin RXD
• the MISO line is driven by the output pin TXD
• the CLK line drives the input pin CLK
• the NSS line drives the input pin CTS
In order to avoid unpredicted behavior, any change of the SPI Mode must be followed by a software reset of the transmitter and of the receiver (except the initial configuration after a hardware
reset).
25.6.8.2
Baud Rate
In SPI Mode, the baudrate generator operates in the same way as in USART synchronous
mode: See Section “25.6.1.4” on page 549. However, there are some restrictions:
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In SPI Master Mode:
• the external clock CLK must not be selected (USCLKS … 0x3), and the bit CLKO must be set
to “1” in the Mode Register (MR), in order to generate correctly the serial clock on the CLK
pin.
• to obtain correct behavior of the receiver and the transmitter, the value programmed in CD of
must be superior or equal to 4.
• if the internal clock divided (CLK_USART/DIV) is selected, the value programmed in CD must
be even to ensure a 50:50 mark/space ratio on the CLK pin, this value can be odd if the
internal clock is selected (CLK_USART).
In SPI Slave Mode:
• the external clock (CLK) selection is forced regardless of the value of the USCLKS field in the
Mode Register (MR). Likewise, the value written in BRGR has no effect, because the clock is
provided directly by the signal on the USART CLK pin.
• to obtain correct behavior of the receiver and the transmitter, the external clock (CLK)
frequency must be at least 4 times lower than the system clock.
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25.6.8.3
Data Transfer
Up to 9 data bits are successively shifted out on the TXD pin at each rising or falling edge
(depending of CPOL and CPHA) of the programmed serial clock. There is no Start bit, no Parity
bit and no Stop bit.
The number of data bits is selected by the CHRL field and the MODE 9 bit in the Mode Register
(MR). The 9 bits are selected by setting the MODE 9 bit regardless of the CHRL field. The MSB
data bit is always sent first in SPI Mode (Master or Slave).
Four combinations of polarity and phase are available for data transfers. The clock polarity is
programmed with the CPOL bit in the Mode Register. The clock phase is programmed with the
CPHA bit. These two parameters determine the edges of the clock signal upon which data is
driven and sampled. Each of the two parameters has two possible states, resulting in four possible combinations that are incompatible with one another. Thus, a master/slave pair must use the
same parameter pair values to communicate. If multiple slaves are used and fixed in different
configurations, the master must reconfigure itself each time it needs to communicate with a different slave.
Table 25-13. SPI Bus Protocol Mode
SPI Bus Protocol Mode
CPOL
CPHA
0
0
1
1
0
0
2
1
1
3
1
0
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Figure 25-37. SPI Transfer Format (CPHA=1, 8 bits per transfer)
CLK cycle (for reference)
2
1
4
3
5
7
6
8
CLK
(CPOL= 0)
CLK
(CPOL= 1)
MOSI
SPI Master ->TXD
SPI Slave ->RXD
MISO
SPI Master ->RXD
SPI Slave ->TXD
MSB
MSB
6
5
4
3
2
1
LSB
6
5
4
3
2
1
LSB
NSS
SPI Master ->RTS
SPI Slave ->CTS
Figure 25-38. SPI Transfer Format (CPHA=0, 8 bits per transfer)
CLK cycle (for reference)
1
2
3
4
5
6
7
8
CLK
(CPOL= 0)
CLK
(CPOL= 1)
MOSI
SPI Master -> TXD
SPI Slave -> RXD
MSB
6
5
4
3
2
1
LSB
MISO
SPI Master -> RXD
SPI Slave -> TXD
MSB
6
5
4
3
2
1
LSB
NSS
SPI Master -> RTS
SPI Slave -> CTS
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25.6.8.4
Receiver and Transmitter Control
See Section “25.6.2” on page 551.
25.6.8.5
Character Transmission
The characters are sent by writing in the Transmit Holding Register (THR). The transmitter
reports two status bits in the Channel Status Register (CSR): TXRDY (Transmitter Ready),
which indicates that THR is empty and TXEMPTY, which indicates that all the characters written
in THR have been processed. When the current character processing is completed, the last
character written in THR is transferred into the Shift Register of the transmitter and THR
becomes empty, thus TXRDY rises.
Both TXRDY and TXEMPTY bits are low when the transmitter is disabled. Writing a character in
THR while TXRDY is low has no effect and the written character is lost.
If the USART is in SPI Slave Mode and if a character must be sent while the Transmit Holding
Register (THR) is empty, the UNRE (Underrun Error) bit is set. The TXD transmission line stays
at high level during all this time. The UNRE bit is cleared by writing the Control Register (CR)
with the RSTSTA (Reset Status) bit at 1.
In SPI Master Mode, the slave select line (NSS) is asserted at low level 1 Tbit before the transmission of the MSB bit and released at high level 1 Tbit after the transmission of the LSB bit. So,
the slave select line (NSS) is always released between each character transmission and a minimum delay of 3 Tbits always inserted. However, in order to address slave devices supporting the
CSAAT mode (Chip Select Active After Transfer), the slave select line (NSS) can be forced at
low level by writing the Control Register (CR) with the RTSEN bit at 1. The slave select line
(NSS) can be released at high level only by writing the Control Register (CR) with the RTSDIS
bit at 1 (for example, when all data have been transferred to the slave device).
In SPI Slave Mode, the transmitter does not require a falling edge of the slave select line (NSS)
to initiate a character transmission but only a low level. However, this low level must be present
on the slave select line (NSS) at least 1 Tbit before the first serial clock cycle corresponding to
the MSB bit.
25.6.8.6
Character Reception
When a character reception is completed, it is transferred to the Receive Holding Register
(RHR) and the RXRDY bit in the Status Register (CSR) rises. If a character is completed while
RXRDY is set, the OVRE (Overrun Error) bit is set. The last character is transferred into RHR
and overwrites the previous one. The OVRE bit is cleared by writing the Control Register (CR)
with the RSTSTA (Reset Status) bit at 1.
To ensure correct behavior of the receiver in SPI Slave Mode, the master device sending the
frame must ensure a minimum delay of 1 Tbit between each character transmission. The
receiver does not require a falling edge of the slave select line (NSS) to initiate a character
reception but only a low level. However, this low level must be present on the slave select line
(NSS) at least 1 Tbit before the first serial clock cycle corresponding to the MSB bit.
25.6.8.7
Receiver Timeout
Because the receiver baudrate clock is active only during data transfers in SPI Mode, a receiver
timeout is impossible in this mode, whatever the Time-out value is (field TO) in the Time-out
Register (RTOR).
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25.6.9
LIN Mode
The LIN Mode provides Master node and Slave node connectivity on a LIN bus.
The LIN (Local Interconnect Network) is a serial communication protocol which efficiently supports the control of mechatronic nodes in distributed automotive applications.
The main properties of the LIN bus are:
• Single Master/Multiple Slaves concept
• Low cost silicon implementation based on common UART/SCI interface hardware, an
equivalent in software, or as a pure state machine.
• Self synchronization without quartz or ceramic resonator in the slave nodes
• Deterministic signal transmission
• Low cost single-wire implementation
• Speed up to 20 kbit/s
LIN provides cost efficient bus communication where the bandwidth and versatility of CAN are
not required.
The LIN Mode enables processing LIN frames with a minimum of action from the
microprocessor.
25.6.9.1
Modes of operation
The USART can act either as a LIN Master node or as a LIN Slave node.
The node configuration is chosen by setting the MODE field in the Mode Register (MR):
• LIN Master Node (MODE=0xA)
• LIN Slave Node (MODE=0xB)
In order to avoid unpredicted behavior, any change of the LIN node configuration must be followed by a software reset of the transmitter and of the receiver (except the initial node
configuration after a hardware reset). (See Section 25.6.9.2)
25.6.9.2
Receiver and Transmitter Control
See Section “25.6.2” on page 551.
25.6.9.3
Character Transmission
See Section “25.6.3.1” on page 552.
25.6.9.4
Character Reception
See Section “25.6.3.7” on page 560.
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25.6.9.5
Header Transmission (Master Node Configuration)
All the LIN Frames start with a header which is sent by the master node and consists of a Synch
Break Field, Synch Field and Identifier Field.
So in Master node configuration, the frame handling starts with the sending of the header.
The header is transmitted as soon as the identifier is written in the LIN Identifier register (LINIR).
At this moment the flag TXRDY falls.
The Break Field, the Synch Field and the Identifier Field are sent automatically one after the
other.
The Break Field consists of 13 dominant bits and 1 recessive bit, the Synch Field is the character 0x55 and the Identifier corresponds to the character written in the LIN Identifier Register
(LINIR). The Identifier parity bits can be automatically computed and sent (see Section
25.6.9.8).
The flag TXRDY rises when the identifier character is transferred into the Shift Register of the
transmitter.
Figure 25-39. Header Transmission
Baud Rate
Clock
TXD
Break Field
13 dominant bits (at 0)
Write
LINIR
LINIR
Break
Delimiter
1 recessive bit
(at 1)
Start
1
Bit
0
1
0
1
0
Synch Byte = 0x55
1
0
Stop Start
Stop
ID0 ID1 ID2 ID3 ID4 ID5 ID6 ID7
Bit Bit
Bit
ID
TXRDY
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25.6.9.6
Header Reception (Slave Node Configuration)
All the LIN Frames start with a header which is sent by the master node and consists of a Synch
Break Field, Synch Field and Identifier Field.
In Slave node configuration, the frame handling starts with the reception of the header.
The USART uses a break detection threshold of 11 nominal bit times at the actual baud rate. At
any time, if 11 consecutive recessive bits are detected on the bus, the USART detects a Break
Field. As long as a Break Field has not been detected, the USART stays idle and the received
data are not taken in account.
When a Break Field has been detected, the USART expects the Synch Field character to be
0x55. This field is used to update the actual baud rate in order to stay synchronized (see Section
25.6.9.7). If the received Synch character is not 0x55, an Inconsistent Synch Field error is generated (see Section 25.6.10).
After receiving the Synch Field, the USART expects to receive the Identifier Field.
When the Identifier has been received, the flag LINID is set to “1”. At this moment the field
IDCHR in the LIN Identifier register (LINIR) is updated with the received character. The Identifier
parity bits can be automatically computed and checked (see Section 25.6.9.8).
Figure 25-40. Header Reception
Baud Rate
Clock
RXD
Break Field
13 dominant bits (at 0)
LINID
Break
Delimiter
1 recessive bit
(at 1)
Start
1
Bit
0
1
0
1
0
1
0
Synch Byte = 0x55
Stop
Stop Start
ID0 ID1 ID2 ID3 ID4 ID5 ID6 ID7
Bit
Bit Bit
US_LINIR
Write US_CR
With RSTSTA=1
25.6.9.7
Slave Node Synchronization
The synchronization is done only in Slave node configuration. The procedure is based on time
measurement between falling edges of the Synch Field. The falling edges are available in distances of 2, 4, 6 and 8 bit times.
Figure 25-41. Synch Field
Synch Field
8 Tbit
2 Tbit
Start
bit
2 Tbit
2 Tbit
2 Tbit
Stop
bit
The time measurement is made by a 19-bit counter clocked by the sampling clock (see Section
25.6.1).
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When the start bit of the Synch Field is detected the counter is reset. Then during the next 8
Tbits of the Synch Field, the counter is incremented. At the end of these 8 Tbits, the counter is
stopped. At this moment, the 16 most significant bits of the counter (value divided by 8) gives the
new clock divider (CD) and the 3 least significant bits of this value (the remainder) gives the new
fractional part (FP).
When the Synch Field has been received, the clock divider (CD) and the fractional part (FP) are
updated in the Baud Rate Generator register (BRGR).
Figure 25-42. Slave Node Synchronization
Baud Rate
Clock
RXD
Break Field
13 dominant bits (at 0)
Break
Delimiter
1 recessive bit
(at 1)
Start
1
Bit
0
1
0
1
0
Synch Byte = 0x55
1
0
Stop Start
Stop
ID0 ID1 ID2 ID3 ID4 ID5 ID6 ID7
Bit Bit
Bit
LINIDRX
Reset
Synchro Counter
000_0011_0001_0110_1101
BRGR
Clcok Divider (CD)
Initial CD
0000_0110_0010_1101
BRGR
Fractional Part (FP)
Initial FP
101
The accuracy of the synchronization depends on several parameters:
• The nominal clock frequency (FNom) (the theoretical slave node clock frequency)
• The Baudrate
• The oversampling (Over=0 => 16X or Over=0 => 8X)
The following formula is used to compute the deviation of the slave bit rate relative to the master
bit rate after synchronization (FSLAVE is the real slave node clock frequency).
[ α × 8 × ( 2 – Over ) + β ] × Baudrate
Baudrate_deviation = ⎛ 100 × ---------------------------------------------------------------------------------------------⎞ %
⎝
⎠
8 × F SLAVE
⎛
⎞
⎜
[ α × 8 × ( 2 – Over ) + β ] × Baudrate⎟
Baudrate_deviation = ⎜ 100 × ---------------------------------------------------------------------------------------------⎟ %
F TOL_UNSYNCH
⎜
⎟
8 × ⎛ ---------------------------------------⎞ xF Nom
⎝
⎠
⎝
⎠
100
– 0.5 ≤ α ≤ +0.5
-1 < β < +1
FTOL_UNSYNCH is the deviation of the real slave node clock from the nominal clock frequency. The
LIN Standard imposes that it must not exceed ±15%. The LIN Standard imposes also that for
communication between two nodes, their bit rate must not differ by more than ±2%. This means
that the Baudrate_deviation must not exceed ±1%.
It follows from that, a minimum value for the nominal clock frequency:
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⎛
⎞
⎜
[ 0.5 × 8 × ( 2 – Over ) + 1 ] × Baudrate⎟
F NOM ( min ) = ⎜ 100 × ------------------------------------------------------------------------------------------------⎟ Hz
– 15- + 1⎞ × 1%
⎜
⎟
8 × ⎛ --------⎝
⎠
⎝ 100
⎠
Examples:
• Baudrate = 20 kbit/s, Over=0 (Oversampling 16X) => FNom(min) = 2.64 MHz
• Baudrate = 20 kbit/s, Over=1 (Oversampling 8X) => FNom(min) = 1.47 MHz
• Baudrate = 1 kbit/s, Over=0 (Oversampling 16X) => FNom(min) = 132 kHz
• Baudrate = 1 kbit/s, Over=1 (Oversampling 8X) => FNom(min) = 74 kHz
If the fractional baud rate is not used, the accuracy of the synchronization becomes much lower.
When the counter is stopped, the 16 most significant bits of the counter (value divided by 8)
gives the new clock divider (CD). This value is rounded by adding the first insignificant bit. The
equation of the Baudrate deviation is the same as given above, but the constants are as follows:
– 4 ≤ α ≤ +4
-1 < β < +1
It follows from that, a minimum value for the nominal clock frequency:
⎛
⎞
⎜
[-----------------------------------------------------------------------------------------4 × 8 × ( 2 – Over ) + 1 ] × Baudrate-⎟
F
(min) = ⎜ 100 ×
⎟ Hz
NOM
– 15- + 1⎞ × 1%
⎜
⎟
⎛ --------8
×
⎝
⎠
⎝ 100
⎠
Examples:
• Baudrate = 20 kbit/s, Over=0 (Oversampling 16X) => FNom(min) = 19.12 MHz
• Baudrate = 20 kbit/s, Over=1 (Oversampling 8X) => FNom(min) = 9.71 MHz
• Baudrate = 1 kbit/s, Over=0 (Oversampling 16X) => FNom(min) = 956 kHz
• Baudrate = 1 kbit/s, Over=1 (Oversampling 8X) => FNom(min) = 485 kHz
25.6.9.8
Identifier Parity
A protected identifier consists of two sub-fields; the identifier and the identifier parity. Bits 0 to 5
are assigned to the identifier and bits 6 and 7 are assigned to the parity.
The USART interface can generate/check these parity bits, but this feature can also be disabled.
The user can choose between two modes by the PARDIS bit of the LIN Mode register (LINMR):
• PARDIS = 0:
During header transmission, the parity bits are computed and sent with the 6 least significant
bits of the IDCHR field of the LIN Identifier register (LINIR). The bits 6 and 7 of this register are
discarded.
During header reception, the parity bits of the identifier are checked. If the parity bits are wrong,
an Identifier Parity error occurs (see Section 25.6.3.8). Only the 6 least significant bits of the
IDCHR field are updated with the received Identifier. The bits 6 and 7 are stuck at 0.
• PARDIS = 1:
During header transmission, all the bits of the IDCHR field of the LIN Identifier register (LINIR)
are sent on the bus.
During header reception, all the bits of the IDCHR field are updated with the received Identifier.
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25.6.9.9
Node Action
In function of the identifier, the node is concerned, or not, by the LIN response. Consequently,
after sending or receiving the identifier, the USART must be configured. There are three possible configurations:
• PUBLISH: the node sends the response.
• SUBSCRIBE: the node receives the response.
• IGNORE: the node is not concerned by the response, it does not send and does not receive
the response.
This configuration is made by the field, Node Action (NACT), in the LINMR register (see Section
25.7.16).
Example: a LIN cluster that contains a Master and two Slaves:
• Data transfer from the Master to the Slave 1 and to the Slave 2:
NACT(Master)=PUBLISH
NACT(Slave1)=SUBSCRIBE
NACT(Slave2)=SUBSCRIBE
• Data transfer from the Master to the Slave 1 only:
NACT(Master)=PUBLISH
NACT(Slave1)=SUBSCRIBE
NACT(Slave2)=IGNORE
• Data transfer from the Slave 1 to the Master:
NACT(Master)=SUBSCRIBE
NACT(Slave1)=PUBLISH
NACT(Slave2)=IGNORE
• Data transfer from the Slave1 to the Slave2:
NACT(Master)=IGNORE
NACT(Slave1)=PUBLISH
NACT(Slave2)=SUBSCRIBE
• Data transfer from the Slave2 to the Master and to the Slave1:
NACT(Master)=SUBSCRIBE
NACT(Slave1)=SUBSCRIBE
NACT(Slave2)=PUBLISH
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25.6.9.10
Response Data Length
The LIN response data length is the number of data fields (bytes) of the response excluding the
checksum.
The response data length can either be configured by the user or be defined automatically by
bits 4 and 5 of the Identifier (compatibility to LIN Specification 1.1). The user can choose
between these two modes by the DLM bit of the LIN Mode register (LINMR):
• DLM = 0: the response data length is configured by the user via the DLC field of the LIN
Mode register (LINMR). The response data length is equal to (DLC + 1) bytes. DLC can be
programmed from 0 to 255, so the response can contain from 1 data byte up to 256 data
bytes.
• DLM = 1: the response data length is defined by the Identifier (IDCHR in LINIR) according to
the table below. The DLC field of the LIN Mode register (LINMR) is discarded. The response
can contain 2 or 4 or 8 data bytes.
Table 25-14. Response Data Length if DLM = 1
IDCHR[5]
IDCHR[4]
Response Data Length [bytes]
0
0
2
0
1
2
1
0
4
1
1
8
Figure 25-43. Response Data Length
User configuration: 1 - 256 data fields (DLC+1)
Identifier configuration: 2/4/8 data fields
Sync
Break
Sync
Field
Identifier
Field
Data
Field
Data
Field
Data
Field
Data
Field
Checksum
Field
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25.6.9.11
Checksum
The last field of a frame is the checksum. The checksum contains the inverted 8- bit sum with
carry, over all data bytes or all data bytes and the protected identifier. Checksum calculation
over the data bytes only is called classic checksum and it is used for communication with LIN 1.3
slaves. Checksum calculation over the data bytes and the protected identifier byte is called
enhanced checksum and it is used for communication with LIN 2.0 slaves.
The USART can be configured to:
• Send/Check an Enhanced checksum automatically (CHKDIS = 0 & CHKTYP = 0)
• Send/Check a Classic checksum automatically (CHKDIS = 0 & CHKTYP = 1)
• Not send/check a checksum (CHKDIS = 1)
This configuration is made by the Checksum Type (CHKTYP) and Checksum Disable (CHKDIS)
fields of the LIN Mode register (LINMR).
If the checksum feature is disabled, the user can send it manually all the same, by considering
the checksum as a normal data byte and by adding 1 to the response data length (see Section
25.6.9.10).
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25.6.9.12
Frame Slot Mode
This mode is useful only for Master nodes. It respects the following rule: each frame slot shall be
longer than or equal to TFrame_Maximum.
If the Frame Slot Mode is enabled (FSDIS = 0) and a frame transfer has been completed, the
TXRDY flag is set again only after TFrame_Maximum delay, from the start of frame. So the Master node cannot send a new header if the frame slot duration of the previous frame is inferior to
TFrame_Maximum.
If the Frame Slot Mode is disabled (FSDIS = 1) and a frame transfer has been completed, the
TXRDY flag is set again immediately.
The TFrame_Maximum is calculated as below:
If the Checksum is sent (CHKDIS = 0):
• THeader_Nominal = 34 x TBit
• TResponse_Nominal = 10 x (NData + 1) x TBit
• TFrame_Maximum = 1.4 x (THeader_Nominal + TResponse_Nominal + 1)(Note:)
• TFrame_Maximum = 1.4 x (34 + 10 x (DLC + 1 + 1) + 1) x TBIT
• TFrame_Maximum = (77 + 14 x DLC) x TBIT
If the Checksum is not sent (CHKDIS = 1):
• THeader_Nominal = 34 x TBit
• TResponse_Nominal = 10 x NData x TBit
• TFrame_Maximum = 1.4 x (THeader_Nominal + TResponse_Nominal + 1(Note:))
• TFrame_Maximum = 1.4 x (34 + 10 x (DLC + 1) + 1) x TBIT
• TFrame_Maximum = (63 + 14 x DLC) x TBIT
Note:
The term “+1” leads to an integer result for TFrame_Max (LIN Specification 1.3)
Figure 25-44. Frame Slot Mode
Frame slot = TFrame_Maximum
Frame
Header
Break
Synch
Data3
Interframe
space
Response
space
Protected
Identifier
Response
Data 1
Data N-1
Data N
Checksum
TXRDY
Frame Slot Mode Frame Slot Mode
Disabled
Enabled
Write
LINID
Write
THR
Data 1
Data 2
Data 3
Data N
LINTC
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25.6.10
25.6.10.1
LIN Errors
Bit Error
This error is generated when the USART is transmitting and if the transmitted value on the Tx
line is different from the value sampled on the Rx line.
If a bit error is detected, the transmission is aborted at the next byte border.
25.6.10.2
Inconsistent Synch Field Error
This error is generated in Slave node configuration if the Synch Field character received is other
than 0x55.
25.6.10.3
Parity Error
This error is generated if the parity of the identifier is wrong. This error can be generated only if
the parity feature is enabled (PARDIS = 0).
25.6.10.4
Checksum Error
This error is set if the received checksum is wrong. This error can be generated only if the
checksum feature is enabled (CHKDIS = 0).
25.6.10.5
Slave Not Responding Error
This error is set when the USART expects a response from another node (NACT = SUBSCRIBE) but no valid message appears on the bus within the time frame given by the maximum
length of the message frame, TFrame_Maximum (see Section 25.6.9.12). This error is disabled
if the USART does not expect any message (NACT = PUBLISH or NACT = IGNORE).
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25.6.11
25.6.11.1
LIN Frame Handling
Master Node Configuration
• Write TXEN and RXEN in CR to enable both the transmitter and the receiver.
• Write MODE in MR to select the LIN mode and the Master Node configuration.
• Write CD and FP in BRGR to configure the baud rate.
• Write NACT, PARDIS, CHKDIS, CHKTYPE, DLCM, FSDIS and DLC in LINMR to configure
the frame transfer.
• Check that TXRDY in CSR is set to “1”
• Write IDCHR in LINIR to send the header
What comes next depends on the NACT configuration:
• Case 1: NACT = PUBLISH, the USART sends the response
– Wait until TXRDY in CSR rises
– Write TCHR in THR to send a byte
– If all the data have not been written, redo the two previous steps
– Wait until LINTC in CSR rises
– Check the LIN errors
• Case 2: NACT = SUBSCRIBE, the USART receives the response
– Wait until RXRDY in CSR rises
– Read RCHR in RHR
– If all the data have not been read, redo the two previous steps
– Wait until LINTC in CSR rises
– Check the LIN errors
• Case 3: NACT = IGNORE, the USART is not concerned by the response
– Wait until LINTC in CSR rises
– Check the LIN errors
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Figure 25-45. Master Node Configuration, NACT = PUBLISH
Frame slot = TFrame_Maximum
Frame
Header
Break
Synch
Data3
Interframe
space
Response
space
Protected
Identifier
Response
Data 1
Data N-1
Data N
Checksum
TXRDY
FSDIS=1
FSDIS=0
RXRDY
Write
LINIR
Write
THR
Data 1
Data 2
Data 3
Data N
LINTC
Figure 25-46. Master Node Configuration, NACT=SUBSCRIBE
Frame slot = TFrame_Maximum
Frame
Header
Break
Synch
Data3
Interframe
space
Response
space
Protected
Identifier
Response
Data 1
Data N-1
Data N
Checksum
TXRDY
FSDIS=1 FSDIS=0
RXRDY
Write
LINIR
Read
RHR
Data 1
Data N-2
Data N-1
Data N
LINTC
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Figure 25-47. Master Node Configuration, NACT=IGNORE
Frame slot = TFrame_Maximum
Frame
Break
Response
space
Header
Data3
Synch
Protected
Identifier
Interframe
space
Response
Data 1
Data N-1
Data N
Checksum
TXRDY
FSDIS=1
FSDIS=0
RXRDY
Write
LINIR
LINTC
25.6.11.2
Slave Node Configuration
• Write TXEN and RXEN in CR to enable both the transmitter and the receiver.
• Write MODE in MR to select the LIN mode and the Slave Node configuration.
• Write CD and FP in BRGR to configure the baud rate.
• Wait until LINID in CSR rises
• Check LINISFE and LINPE errors
• Read IDCHR in RHR
• Write NACT, PARDIS, CHKDIS, CHKTYPE, DLCM and DLC in LINMR to configure the frame
transfer.
IMPORTANT: if the NACT configuration for this frame is PUBLISH, the US_LINMR register,
must be write with NACT=PUBLISH even if this field is already correctly configured, that in order
to set the TXREADY flag and the corresponding Peripheral DMA Controller write transfer
request.
What comes next depends on the NACT configuration:
• Case 1: NACT = PUBLISH, the USART sends the response
– Wait until TXRDY in CSR rises
– Write TCHR in THR to send a byte
– If all the data have not been written, redo the two previous steps
– Wait until LINTC in CSR rises
– Check the LIN errors
• Case 2: NACT = SUBSCRIBE, the USART receives the response
– Wait until RXRDY in CSR rises
– Read RCHR in RHR
– If all the data have not been read, redo the two previous steps
– Wait until LINTC in CSR rises
– Check the LIN errors
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• Case 3: NACT = IGNORE, the USART is not concerned by the response
– Wait until LINTC in CSR rises
– Check the LIN errors
Figure 25-48. Slave Node Configuration, NACT = PUBLISH
Break
Synch
Protected
Identifier
Data 1
Data N-1
Data N
Checksum
Data N
Checksum
TXRDY
RXRDY
LINIDRX
Read
LINID
Write
THR
Data 1 Data 2
Data 3
Data N
LINTC
Figure 25-49. Slave Node Configuration, NACT = SUBSCRIBE
Break
Synch
Protected
Identifier
Data 1
Data N-1
TXRDY
RXRDY
LINIDRX
Read
LINID
Read
RHR
Data 1
Data N-2
Data N-1
Data N
LINTC
Figure 25-50. Slave Node Configuration, NACT = IGNORE
Break
Synch
Protected
Identifier
Data 1
Data N-1
Data N
Checksum
TXRDY
RXRDY
LINIDRX
Read
LINID
Read
RHR
LINTC
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25.6.12
LIN Frame Handling With The Peripheral DMA Controller
The USART can be used in association with the Peripheral DMA Controller in order to transfer
data directly into/from the on- and off-chip memories without any processor intervention.
The Peripheral DMA Controller uses the trigger flags, TXRDY and RXRDY, to write or read into
the USART. The Peripheral DMA Controller always writes in the Transmit Holding register (THR)
and it always reads in the Receive Holding register (RHR). The size of the data written or read by
the Peripheral DMA Controller in the USART is always a byte.
25.6.12.1
Master Node Configuration
The user can choose between two Peripheral DMA Controller modes by the PDCM bit in the LIN
Mode register (LINMR):
• PDCM = 1: the LIN configuration is stored in the WRITE buffer and it is written by the
Peripheral DMA Controller in the Transmit Holding register THR (instead of the LIN Mode
register LINMR). Because the Peripheral DMA Controller transfer size is limited to a byte, the
transfer is split into two accesses. During the first access the bits, NACT, PARDIS, CHKDIS,
CHKTYP, DLM and FSDIS are written. During the second access the 8-bit DLC field is
written.
• PDCM = 0: the LIN configuration is not stored in the WRITE buffer and it must be written by
the user in the LIN Mode register (LINMR).
The WRITE buffer also contains the Identifier and the DATA, if the USART sends the response
(NACT = PUBLISH).
The READ buffer contains the DATA if the USART receives the response (NACT =
SUBSCRIBE).
Figure 25-51. Master Node with Peripheral DMA Controller (PDCM=1)
WRITE BUFFER
WRITE BUFFER
NACT
PARDIS
CHKDIS
CHKTYP
DLM
FSDIS
NACT
PARDIS
CHKDIS
CHKTYP
DLM
FSDIS
DLC
DLC
Peripheral
bus
NODE ACTION = PUBLISH
Peripheral
bus
IDENTIFIER
IDENTIFIER
USART LIN
CONTROLLER
Peripheral DMA
Controller
DATA 0
|
|
|
|
DATA N
READ BUFFER
Peripheral DMA
Controller
RXRDY
NODE ACTION = SUBSCRIBE
USART LIN
CONTROLLER
RXRDY
DATA 0
TXRDY
|
|
|
|
DATA N
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Figure 25-52. Master Node with Peripheral DMA Controller (PDCM=0)
WRITE BUFFER
DATA 0
Peripheral
bus
DATA 1
NODE ACTION = SUBSCRIBE
Peripheral
bus
READ BUFFER
Peripheral DMA
Controller
|
|
|
|
NODE ACTION = PUBLISH
USART LIN
CONTROLLER
DATA 0
RXRDY
Peripheral DMA
Controller
RXRDY
USART LIN
CONTROLLER
TXRDY
|
|
|
|
DATA N
DATA N
25.6.12.2
Slave Node Configuration
In this configuration, the Peripheral DMA Controller transfers only the DATA. The Identifier must
be read by the user in the LIN Identifier register (LINIR). The LIN mode must be written by the
user in the LIN Mode register (LINMR).
The WRITE buffer contains the DATA if the USART sends the response (NACT=PUBLISH).
The READ buffer contains the DATA if the USART receives the response
(NACT=SUBSCRIBE).
IMPORTANT: if the NACT configuration for a frame is PUBLISH, the US_LINMR register, must
be write with NACT=PUBLISH even if this field is already correctly configured, that in order to set
the TXREADY flag and the corresponding Peripheral DMA Controller write transfer request.
Figure 25-53. Slave Node with Peripheral DMA Controller
WRITE BUFFER
READ BUFFER
DATA 0
|
|
|
|
DATA N
DATA 0
Peripheral
bus
Peripheral
Bus
USART LIN
CONTROLLER
Peripheral DMA
Controller
TXRDY
|
|
|
|
Peripheral DMA
Controller
NACT = SUBSCRIBE
USART LIN
CONTROLLER
RXRDY
DATA N
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25.6.13
Wake-up Request
Any node in a sleeping LIN cluster may request a wake-up.
In the LIN 2.0 specification, the wakeup request is issued by forcing the bus to the dominant
state from 250 µs to 5 ms. For this, it is necessary to send the character 0xF0 in order to impose
5 successive dominant bits. Whatever the baud rate is, this character respects the specified
timings.
• Baud rate min = 1 kbit/s -> Tbit = 1ms -> 5 Tbits = 5 ms
• Baud rate max = 20 kbit/s -> Tbi t= 50 µs -> 5 Tbits = 250 µs
In the LIN 1.3 specification, the wakeup request should be generated with the character 0x80 in
order to impose 8 successive dominant bits.
The user can choose by the WKUPTYP bit in the LIN Mode register (LINMR) either to send a
LIN 2.0 wakeup request (WKUPTYP=0) or to send a LIN 1.3 wakeup request (WKUPTYP=1).
A wake-up request is transmitted by writing the Control Register (CR) with the LINWKUP bit at 1.
Once the transfer is completed, the LINTC flag is asserted in the Status Register (SR). It is
cleared by writing the Control Register (CR) with the RSTSTA bit at 1.
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25.6.14
Bus Idle Time-out
If the LIN bus is inactive for a certain duration, the slave nodes shall automatically enter in sleep
mode. In the LIN 2.0 specification, this time-out is fixed at 4 seconds. In the LIN 1.3 specification, it is fixed at 25000 Tbits.
In Slave Node configuration, the Receiver Time-out detects an idle condition on the RXD line.
When a time-out is detected, the bit TIMEOUT in the Channel Status Register (CSR) rises and
can generate an interrupt, thus indicating to the driver to go into sleep mode.
The time-out delay period (during which the receiver waits for a new character) is programmed
in the TO field of the Receiver Time-out Register (RTOR). If the TO field is programmed at 0, the
Receiver Time-out is disabled and no time-out is detected. The TIMEOUT bit in CSR remains at
0. Otherwise, the receiver loads a 17-bit counter with the value programmed in TO. This counter
is decremented at each bit period and reloaded each time a new character is received. If the
counter reaches 0, the TIMEOUT bit in the Status Register rises.
If STTTO is performed, the counter clock is stopped until a first character is received.
If RETTO is performed, the counter starts counting down immediately from the value TO.
Table 25-15. Receiver Time-out programming
LIN Specification
2.0
1.3
Baud Rate
Time-out period
TO
1 000 bit/s
4 000
2 400 bit/s
9 600
9 600 bit/s
4s
38 400
19 200 bit/s
76 800
20 000 bit/s
80 000
-
25 000 Tbits
25 000
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25.6.15
Test Modes
The USART can be programmed to operate in three different test modes. The internal loopback
capability allows on-board diagnostics. In the loopback mode the USART interface pins are disconnected or not and reconfigured for loopback internally or externally.
25.6.15.1
Normal Mode
Normal mode connects the RXD pin on the receiver input and the transmitter output on the TXD
pin.
Figure 25-54. Normal Mode Configuration
RXD
Receiver
TXD
Transmitter
25.6.15.2
Automatic Echo Mode
Automatic echo mode allows bit-by-bit retransmission. When a bit is received on the RXD pin, it
is sent to the TXD pin, as shown in Figure 25-55. Programming the transmitter has no effect on
the TXD pin. The RXD pin is still connected to the receiver input, thus the receiver remains
active.
Figure 25-55. Automatic Echo Mode Configuration
RXD
Receiver
TXD
Transmitter
25.6.15.3
Local Loopback Mode
Local loopback mode connects the output of the transmitter directly to the input of the receiver,
as shown in Figure 25-56. The TXD and RXD pins are not used. The RXD pin has no effect on
the receiver and the TXD pin is continuously driven high, as in idle state.
Figure 25-56. Local Loopback Mode Configuration
RXD
Receiver
Transmitter
1
TXD
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25.6.15.4
Remote Loopback Mode
Remote loopback mode directly connects the RXD pin to the TXD pin, as shown in Figure 25-57.
The transmitter and the receiver are disabled and have no effect. This mode allows bit-by-bit
retransmission.
Figure 25-57. Remote Loopback Mode Configuration
Receiver
1
RXD
TXD
Transmitter
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25.6.16 Write Protection Registers
To prevent any single software error that may corrupt USART behavior, certain address spaces can be write-protected by
setting the WPEN bit in the USART Write Protect Mode Register (WPMR).
If a write access to the protected registers is detected, then the WPVS flag in the USART Write Protect Status Register
(WPSR) is set and the field WPVSRC indicates in which register the write access has been attempted.
The WPVS flag is reset by writing the USART Write Protect Mode Register (WPMR) with the appropriate access key,
WPKEY.
The protected registers are:
• ”Mode Register” on page 605
• ”Baud Rate Generator Register” on page 615
• ”Receiver Time-out Register” on page 616
• ”Transmitter Timeguard Register” on page 617
• ”FI DI RATIO Register” on page 618
• ”IrDA FILTER Register” on page 620
• ”Manchester Configuration Register” on page 621
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25.7
User Interface
Table 25-16. USART Register Memory Map
Offset
Register
Name
Access
Reset
0x0000
Control Register
CR
Write-only
–
0x0004
Mode Register
MR
Read-write
0x00000000
0x0008
Interrupt Enable Register
IER
Write-only
–
0x000C
Interrupt Disable Register
IDR
Write-only
–
0x0010
Interrupt Mask Register
IMR
Read-only
0x00000000
0x0014
Channel Status Register
CSR
Read-only
0x00000000
0x0018
Receiver Holding Register
RHR
Read-only
0x00000000
0x001C
Transmitter Holding Register
THR
Write-only
–
0x0020
Baud Rate Generator Register
BRGR
Read-write
0x00000000
0x0024
Receiver Time-out Register
RTOR
Read-write
0x00000000
0x0028
Transmitter Timeguard Register
TTGR
Read-write
0x00000000
0x0040
FI DI Ratio Register
FIDI
Read-write
0x00000174
0x0044
Number of Errors Register
NER
Read-only
0x00000000
0x004C
IrDA Filter Register
IFR
Read-write
0x00000000
0x0050
Manchester Encoder Decoder Register
MAN
Read-write
0x30011004
0x0054
LIN Mode Register
LINMR
Read-write
0x00000000
0x0058
LIN Identifier Register
LINIR
Read-write
0x00000000
0x00E4
Write Protect Mode Register
WPMR
Read-write
0x00000000
0x00E8
Write Protect Status Register
WPSR
Read-only
0x00000000
0x00FC
Version Register
VERSION
Read-only
0x–(1)
Note:
1. Values in the Version Register vary with the version of the IP block implementation.
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25.7.1
Name:
Control Register
CR
Access Type:
Write-only
Offset:
0x0
Reset Value:
-
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
LINWKUP
20
LINABT
19
RTSDIS/RCS
18
RTSEN/FCS
17
DTRDIS
16
DTREN
15
RETTO
14
RSTNACK
13
RSTIT
12
SENDA
11
STTTO
10
STPBRK
9
STTBRK
8
RSTSTA
7
TXDIS
6
TXEN
5
RXDIS
4
RXEN
3
RSTTX
2
RSTRX
1
–
0
–
• LINWKUP: Send LIN Wakeup Signal
•
•
•
•
•
•
0: No effect:
1: Sends a wakeup signal on the LIN bus.
LINABT: Abort LIN Transmission
0: No effect.
1: Abort the current LIN transmission.
RTSDIS/RCS: Request to Send Disable/Release SPI Chip Select
If USART does not operate in SPI Master Mode (MODE … 0xE):
0: No effect.
1: Drives the pin RTS to 1.
If USART operates in SPI Master Mode (MODE = 0xE):
RCS = 0: No effect.
RCS = 1: Releases the Slave Select Line NSS (RTS pin).
RTSEN/FCS: Request to Send Enable/Force SPI Chip Select
If USART does not operate in SPI Master Mode (MODE … 0xE):
0: No effect.
1: Drives the pin RTS to 0.
If USART operates in SPI Master Mode (MODE = 0xE):
FCS = 0: No effect.
FCS = 1: Forces the Slave Select Line NSS (RTS pin) to 0, even if USART is no transmitting, in order to address SPI slave
devices supporting the CSAAT Mode (Chip Select Active After Transfer).
DTRDIS: Data Terminal Ready Disable
0: No effect.
1: Drives the pin DTR to 1.
DTREN: Data Terminal Ready Enable
0: No effect.
1: Drives the pin DTR at 0.
RETTO: Rearm Time-out
0: No effect
1: Restart Time-out
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• RSTNACK: Reset Non Acknowledge
•
•
•
•
•
•
•
•
•
•
•
•
0: No effect
1: Resets NACK in CSR.
RSTIT: Reset Iterations
0: No effect.
1: Resets ITERATION in CSR. No effect if the ISO7816 is not enabled.
SENDA: Send Address
0: No effect.
1: In Multidrop Mode only, the next character written to the THR is sent with the address bit set.
STTTO: Start Time-out
0: No effect.
1: Starts waiting for a character before clocking the time-out counter. Resets the status bit TIMEOUT in CSR.
STPBRK: Stop Break
0: No effect.
1: Stops transmission of the break after a minimum of one character length and transmits a high level during 12-bit periods. No
effect if no break is being transmitted.
STTBRK: Start Break
0: No effect.
1: Starts transmission of a break after the characters present in THR and the Transmit Shift Register have been transmitted. No
effect if a break is already being transmitted.
RSTSTA: Reset Status Bits
0: No effect.
1: Resets the status bits PARE, FRAME, OVRE, MANERR, LINBE, LINSFE, LINIPE, LINCE, LINSNRE and RXBRK in CSR.
TXDIS: Transmitter Disable
0: No effect.
1: Disables the transmitter.
TXEN: Transmitter Enable
0: No effect.
1: Enables the transmitter if TXDIS is 0.
RXDIS: Receiver Disable
0: No effect.
1: Disables the receiver.
RXEN: Receiver Enable
0: No effect.
1: Enables the receiver, if RXDIS is 0.
RSTTX: Reset Transmitter
0: No effect.
1: Resets the transmitter.
RSTRX: Reset Receiver
0: No effect.
1: Resets the receiver.
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25.7.2
Name:
Mode Register
MR
Access Type:
Read-write
Offset:
0x4
Reset Value:
-
31
ONEBIT
30
MODSYNC
29
MAN
28
FILTER
27
–
26
25
MAX_ITERATION
24
23
–
22
VAR_SYNC
21
DSNACK
20
INACK
19
OVER
18
CLKO
17
MODE9
16
MSBF/CPOL
14
13
12
11
10
PAR
9
8
SYNC/CPHA
4
3
2
1
0
15
CHMODE
7
NBSTOP
6
5
CHRL
USCLKS
MODE
This register can only be written if the WPEN bit is cleared in the Write Protect Mode Register(if exists).
• ONEBIT: Start Frame Delimiter Selector
•
•
•
•
•
•
•
•
0: Start Frame delimiter is COMMAND or DATA SYNC.
1: Start Frame delimiter is One Bit.
MODSYNC: Manchester Synchronization Mode
0:The Manchester Start bit is a 0 to 1 transition
1: The Manchester Start bit is a 1 to 0 transition.
MAN: Manchester Encoder/Decoder Enable
0: Manchester Encoder/Decoder are disabled.
1: Manchester Encoder/Decoder are enabled.
FILTER: Infrared Receive Line Filter
0: The USART does not filter the receive line.
1: The USART filters the receive line using a three-sample filter (1/16-bit clock) (2 over 3 majority).
MAX_ITERATION
Defines the maximum number of iterations in mode ISO7816, protocol T= 0.
VAR_SYNC: Variable Synchronization of Command/Data Sync Start Frame Delimiter
0: User defined configuration of command or data sync field depending on SYNC value.
1: The sync field is updated when a character is written into THR register.
DSNACK: Disable Successive NACK
0: NACK is sent on the ISO line as soon as a parity error occurs in the received character (unless INACK is set).
1: Successive parity errors are counted up to the value specified in the MAX_ITERATION field. These parity errors generate a
NACK on the ISO line. As soon as this value is reached, no additional NACK is sent on the ISO line. The flag ITERATION is
asserted.
INACK: Inhibit Non Acknowledge
0: The NACK is generated.
1: The NACK is not generated.
OVER: Oversampling Mode
0: 16x Oversampling.
1: 8x Oversampling.
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• CLKO: Clock Output Select
0: The USART does not drive the CLK pin.
1: The USART drives the CLK pin if USCLKS does not select the external clock CLK.
• MODE9: 9-bit Character Length
0: CHRL defines character length.
1: 9-bit character length.
• MSBF/CPOL: Bit Order or SPI Clock Polarity
If USART does not operate in SPI Mode (MODE … 0xE and 0xF):
MSBF = 0: Least Significant Bit is sent/received first.
MSBF = 1: Most Significant Bit is sent/received first.
If USART operates in SPI Mode (Slave or Master, MODE = 0xE or 0xF):
CPOL = 0: The inactive state value of SPCK is logic level zero.
CPOL = 1: The inactive state value of SPCK is logic level one.
CPOL is used to determine the inactive state value of the serial clock (SPCK). It is used with CPHA to produce the required
clock/data relationship between master and slave devices.
• CHMODE: Channel Mode
Table 25-17.
CHMODE
Mode Description
0
0
Normal Mode
0
1
Automatic Echo. Receiver input is connected to the TXD pin.
1
0
Local Loopback. Transmitter output is connected to the Receiver Input.
1
1
Remote Loopback. RXD pin is internally connected to the TXD pin.
• NBSTOP: Number of Stop Bits
Table 25-18.
NBSTOP
Asynchronous (SYNC = 0)
Synchronous (SYNC = 1)
0
0
1 stop bit
1 stop bit
0
1
1.5 stop bits
Reserved
1
0
2 stop bits
2 stop bits
1
1
Reserved
Reserved
• PAR: Parity Type
Table 25-19.
PAR
Parity Type
0
0
0
Even parity
0
0
1
Odd parity
0
1
0
Parity forced to 0 (Space)
0
1
1
Parity forced to 1 (Mark)
1
0
x
No parity
1
1
x
Multidrop mode
• SYNC/CPHA: Synchronous Mode Select or SPI Clock Phase
If USART does not operate in SPI Mode (MODE is … 0xE and 0xF):
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SYNC = 0: USART operates in Asynchronous Mode.
SYNC = 1: USART operates in Synchronous Mode.
If USART operates in SPI Mode (MODE = 0xE or 0xF):
CPHA = 0: Data is changed on the leading edge of SPCK and captured on the following edge of SPCK.
CPHA = 1: Data is captured on the leading edge of SPCK and changed on the following edge of SPCK.
CPHA determines which edge of SPCK causes data to change and which edge causes data to be captured. CPHA is used with
CPOL to produce the required clock/data relationship between master and slave devices.
• CHRL: Character Length.
Table 25-20.
CHRL
Character Length
0
0
5 bits
0
1
6 bits
1
0
7 bits
1
1
8 bits
• USCLKS: Clock Selection
Table 25-21.
USCLKS
Selected Clock
0
0
CLK_USART
0
1
CLK_USART/DIV(1)
1
0
Reserved
1
1
CLK
Note:
1. The value of DIV is device dependent. Please refer to the Module Configuration section at the
end of this chapter.
• MODE
Table 25-22.
MODE
Mode of the USART
0
0
0
0
Normal
0
0
0
1
RS485
0
0
1
0
Hardware Handshaking
0
0
1
1
Modem
0
1
0
0
IS07816 Protocol: T = 0
0
1
1
0
IS07816 Protocol: T = 1
1
0
0
0
IrDA
1
0
1
0
LIN Master
1
0
1
1
LIN Slave
1
1
1
0
SPI Master
1
1
1
1
SPI Slave
Others
Reserved
607
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25.7.3
Name:
Interrupt Enable Register
IER
Access Type:
Write-only
Offset:
0x8
Reset Value:
-
31
–
30
–
29
LINSNRE
28
LINCE
27
LINIPE
26
LINISFE
25
LINBE
24
MANEA
23
–
22
–
21
–
20
MANE
19
CTSIC
18
DCDIC
17
DSRIC
16
RIIC
15
LINTC
14
LINiD
13
NACK/LINBK
12
RXBUFF
11
–
10
ITER/UNRE
9
TXEMPTY
8
TIMEOUT
7
PARE
6
FRAME
5
OVRE
4
–
3
–
2
RXBRK
1
TXRDY
0
RXRDY
Writing a zero to a bit in this register has no effect.
Writing a one to a bit in this register will set the corresponding bit in IMR.
For backward compatibility the MANE bit has been duplicated to the MANEA bit position. Writing either one or the other has
the same effect.
608
32072C–AVR32–2010/03
AT32UC3A3/A4
25.7.4
Name:
Interrupt Disable Register
IDR
Access Type:
Write-only
Offset:
0xC
Reset Value:
-
31
–
30
–
29
LINSNRE
28
LINCE
27
LINIPE
26
LINISFE
25
LINBE
24
MANEA
23
–
22
–
21
–
20
MANE
19
CTSIC
18
DCDIC
17
DSRIC
16
RIIC
15
LINTC
14
LINID
13
NACK/LINBK
12
RXBUFF
11
–
10
ITER/UNRE
9
TXEMPTY
8
TIMEOUT
7
PARE
6
FRAME
5
OVRE
4
–
3
–
2
RXBRK
1
TXRDY
0
RXRDY
Writing a zero to a bit in this register has no effect.
Writing a one to a bit in this register will clear the corresponding bit in IMR.
For backward compatibility the MANE bit has been duplicated to the MANEA bit position. Writing either one or the other has
the same effect.
609
32072C–AVR32–2010/03
AT32UC3A3/A4
25.7.5
Name:
Interrupt Mask Register
IMR
Access Type:
Read-only
Offset:
0x10
Reset Value:
-
31
–
30
–
29
LINSNRE
28
LINCE
27
LINIPE
26
LINISFE
25
LINBE
24
MANEA
23
–
22
–
21
–
20
MANE
19
CTSIC
18
DCDIC
17
DSRIC
16
RIIC
15
LINTC
14
LINID
13
NACK/LINBK
12
RXBUFF
11
–
10
ITER/UNRE
9
TXEMPTY
8
TIMEOUT
7
PARE
6
FRAME
5
OVRE
4
–
3
–
2
RXBRK
1
TXRDY
0
RXRDY
0: The corresponding interrupt is disabled.
1: The corresponding interrupt is enabled.
A bit in this register is cleared when the corresponding bit in IDR is written to one.
A bit in this register is set when the corresponding bit in IER is written to one.
For backward compatibility the MANE bit has been duplicated to the MANEA bit position. Reading either one or the other
has the same effect.
25.7.6
Name:
Channel Status Register
CSR
Access Type:
Read-only
Offset:
0x14
Reset Value:
-
31
–
30
–
29
LINSNRE
28
LINCE
27
LINIPE
26
LINISFE
25
LINBE
24
MANERR
23
CTS
22
DCD
21
DSR
20
RI
19
CTSIC
18
DCDIC
17
DSRIC
16
RIIC
15
LINTC
14
LINID
13
NACK/LINBK
12
RXBUFF
11
–
10
ITER/UNRE
9
TXEMPTY
8
TIMEOUT
7
PARE
6
FRAME
5
OVRE
4
–
3
–
2
RXBRK
1
TXRDY
0
RXRDY
• LINSNRE: LIN Slave Not Responding Error
0: No LIN Slave Not Responding Error has been detected since the last RSTSTA.
610
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AT32UC3A3/A4
1: A LIN Slave Not Responding Error has been detected since the last RSTSTA.
• LINCE: LIN Checksum Error
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
0: No LIN Checksum Error has been detected since the last RSTSTA.
1: A LIN Checksum Error has been detected since the last RSTSTA.
LINIPE: LIN Identifier Parity Error
0: No LIN Identifier Parity Error has been detected since the last RSTSTA.
1: A LIN Identifier Parity Error has been detected since the last RSTSTA.
LINISFE: LIN Inconsistent Synch Field Error
0: No LIN Inconsistent Synch Field Error has been detected since the last RSTSTA
1: The USART is configured as a Slave node and a LIN Inconsistent Synch Field Error has been detected since the last
RSTSTA.
LINBE: LIN Bit Error
0: No Bit Error has been detected since the last RSTSTA.
1: A Bit Error has been detected since the last RSTSTA.
MANERR: Manchester Error
0: No Manchester error has been detected since the last RSTSTA.
1: At least one Manchester error has been detected since the last RSTSTA.
CTS: Image of CTS Input
0: CTS is at 0.
1: CTS is at 1.
DCD: Image of DCD Input
0: DCD is at 0.
1: DCD is at 1.
DSR: Image of DSR Input
0: DSR is at 0
1: DSR is at 1.
RI: Image of RI Input
0: RI is at 0.
1: RI is at 1.
CTSIC: Clear to Send Input Change Flag
0: No input change has been detected on the CTS pin since the last read of CSR.
1: At least one input change has been detected on the CTS pin since the last read of CSR.
DCDIC: Data Carrier Detect Input Change Flag
0: No input change has been detected on the DCD pin since the last read of CSR.
1: At least one input change has been detected on the DCD pin since the last read of CSR.
DSRIC: Data Set Ready Input Change Flag
0: No input change has been detected on the DSR pin since the last read of CSR.
1: At least one input change has been detected on the DSR pin since the last read of CSR.
RIIC: Ring Indicator Input Change Flag
0: No input change has been detected on the RI pin since the last read of CSR.
1: At least one input change has been detected on the RI pin since the last read of CSR.
LINTC: LIN Transfer Completed
0: The USART is idle or a LIN transfer is ongoing.
1: A LIN transfer has been completed since the last RSTSTA.
LINID: LIN Identifier
0: No LIN Identifier received or sent
1: The USART is configured as a Slave node and a LIN Identifier has been received or the USART is configured as a Master
node and a LIN Identifier has been sent since the last RSTSTA.
NACK: Non Acknowledge
0: No Non Acknowledge has not been detected since the last RSTNACK.
611
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AT32UC3A3/A4
1: At least one Non Acknowledge has been detected since the last RSTNACK.
• RXBUFF: Reception Buffer Full
•
•
•
•
•
•
•
•
•
0: The signal Buffer Full from the Receive Peripheral DMA Controller channel is inactive.
1: The signal Buffer Full from the Receive Peripheral DMA Controller channel is active.
ITER/UNRE: Max number of Repetitions Reached or SPI Underrun Error
If USART does not operate in SPI Slave Mode (MODE … 0xF):
ITER = 0: Maximum number of repetitions has not been reached since the last RSTSTA.
ITER = 1: Maximum number of repetitions has been reached since the last RSTSTA.
If USART operates in SPI Slave Mode (MODE = 0xF):
UNRE = 0: No SPI underrun error has occurred since the last RSTSTA.
UNRE = 1: At least one SPI underrun error has occurred since the last RSTSTA.
TXEMPTY: Transmitter Empty
0: There are characters in either THR or the Transmit Shift Register, or the transmitter is disabled.
1: There are no characters in THR, nor in the Transmit Shift Register.
TIMEOUT: Receiver Time-out
0: There has not been a time-out since the last Start Time-out command (STTTO in CR) or the Time-out Register is 0.
1: There has been a time-out since the last Start Time-out command (STTTO in CR).
PARE: Parity Error
0: No parity error has been detected since the last RSTSTA.
1: At least one parity error has been detected since the last RSTSTA.
FRAME: Framing Error
0: No stop bit has been detected low since the last RSTSTA.
1: At least one stop bit has been detected low since the last RSTSTA.
OVRE: Overrun Error
0: No overrun error has occurred since the last RSTSTA.
1: At least one overrun error has occurred since the last RSTSTA.
RXBRK: Break Received/End of Break
0: No Break received or End of Break detected since the last RSTSTA.
1: Break Received or End of Break detected since the last RSTSTA.
TXRDY: Transmitter Ready
0: A character is in the THR waiting to be transferred to the Transmit Shift Register, or an STTBRK command has been
requested, or the transmitter is disabled. As soon as the transmitter is enabled, TXRDY becomes 1.
1: There is no character in the THR.
RXRDY: Receiver Ready
0: No complete character has been received since the last read of RHR or the receiver is disabled. If characters were being
received when the receiver was disabled, RXRDY changes to 1 when the receiver is enabled.
1: At least one complete character has been received and RHR has not yet been read.
612
32072C–AVR32–2010/03
AT32UC3A3/A4
25.7.7
Name:
Receive Holding Register
RHR
Access Type:
Read-only
Offset:
0x18
Reset Value:
0x00000000
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
RXSYNH
14
–
13
–
12
–
11
–
10
–
9
–
8
RXCHR
7
6
5
4
3
2
1
0
RXCHR
• RXSYNH: Received Sync
0: Last Character received is a Data.
1: Last Character received is a Command.
• RXCHR: Received Character
Last character received if RXRDY is set.
613
32072C–AVR32–2010/03
AT32UC3A3/A4
25.7.8
Name:
USART Transmit Holding Register
THR
Access Type:
Write-only
Offset:
0x1C
Reset Value:
-
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
TXSYNH
14
–
13
–
12
–
11
–
10
–
9
–
8
TXCHR
7
6
5
4
3
2
1
0
TXCHR
• TXSYNH: Sync Field to be transmitted
0: The next character sent is encoded as a data. Start Frame Delimiter is DATA SYNC.
1: The next character sent is encoded as a command. Start Frame Delimiter is COMMAND SYNC.
• TXCHR: Character to be Transmitted
Next character to be transmitted after the current character if TXRDY is not set.
614
32072C–AVR32–2010/03
AT32UC3A3/A4
25.7.9
Name:
Baud Rate Generator Register
BRGR
Access Type:
Read-write
Offset:
0x20
Reset Value:
0x00000000
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
17
FP
16
15
14
13
12
11
10
9
8
3
2
1
0
CD
7
6
5
4
CD
This register can only be written if the WPEN bit is cleared in the Write Protect Mode Register.
• FP: Fractional Part
0: Fractional divider is disabled.
1 - 7: Baudrate resolution, defined by FP x 1/8.
• CD: Clock Divider
Table 25-23.
MODE ≠ ISO7816
SYNC = 1
or
MODE = SPI
(Master or Slave)
SYNC = 0
CD
OVER = 0
0
1 to 65535
MODE = ISO7816
OVER = 1
Baud Rate Clock Disabled
Baud Rate =
Selected Clock/16/CD
Baud Rate =
Selected Clock/8/CD
Baud Rate =
Selected Clock /CD
Baud Rate = Selected
Clock/CD/FI_DI_RATIO
615
32072C–AVR32–2010/03
AT32UC3A3/A4
25.7.10
Name:
Receiver Time-out Register
RTOR
Access Type:
Read-write
Offset:
0x24
Reset Value:
0x00000000
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
TO
15
14
13
12
11
10
9
8
3
2
1
0
TO
7
6
5
4
TO
This register can only be written if the WPEN bit is cleared in the Write Protect Mode Register.
• TO: Time-out Value
0: The Receiver Time-out is disabled.
1 - 131071: The Receiver Time-out is enabled and the Time-out delay is TO x Bit Period.
Note that the size of the TO counter can change depending of implementation. See the Module Configuration section.
616
32072C–AVR32–2010/03
AT32UC3A3/A4
25.7.11
Name:
Transmitter Timeguard Register
TTGR
Access Type:
Read-write
Offset:
0x28
Reset Value:
0x00000000
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
–
14
–
13
–
12
–
11
–
10
–
9
–
8
–
7
6
5
4
3
2
1
0
TG
This register can only be written if the WPEN bit is cleared in the Write Protect Mode Register.
• TG: Timeguard Value
0: The Transmitter Timeguard is disabled.
1 - 255: The Transmitter timeguard is enabled and the timeguard delay is TG x Bit Period.
617
32072C–AVR32–2010/03
AT32UC3A3/A4
25.7.12
Name:
FI DI RATIO Register
FIDI
Access Type:
Read-write
Offset:
0x40
Reset Value:
0x00000174
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
–
14
–
13
–
12
–
11
–
10
9
FI_DI_RATIO
8
7
6
5
4
3
2
1
0
FI_DI_RATIO
This register can only be written if the WPEN bit is cleared in the Write Protect Mode Register.
• FI_DI_RATIO: FI Over DI Ratio Value
0: If ISO7816 mode is selected, the Baud Rate Generator generates no signal.
1 - 2047: If ISO7816 mode is selected, the Baud Rate is the clock provided on CLK divided by FI_DI_RATIO.
618
32072C–AVR32–2010/03
AT32UC3A3/A4
25.7.13
Name:
Number of Errors Register
NER
Access Type:
Read-only
Offset:
0x44
Reset Value:
-
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
–
14
–
13
–
12
–
11
–
10
–
9
–
8
–
7
6
5
4
3
2
1
0
NB_ERRORS
• NB_ERRORS: Number of Errors
Total number of errors that occurred during an ISO7816 transfer. This register automatically clears when read.
619
32072C–AVR32–2010/03
AT32UC3A3/A4
25.7.14
Name:
IrDA FILTER Register
IFR
Access Type:
Read-write
Offset:
0x4C
Reset Value:
0x00000000
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
–
14
–
13
–
12
–
11
–
10
–
9
–
8
–
7
6
5
4
3
2
1
0
IRDA_FILTER
This register can only be written if the WPEN bit is cleared in the Write Protect Mode Register(if exists).
IRDA_FILTER: IrDA Filter
Sets the filter of the IrDA demodulator.
620
32072C–AVR32–2010/03
AT32UC3A3/A4
25.7.15
Name:
Manchester Configuration Register
MAN
Access Type:
Read-write
Offset:
0x50
Reset Value:
0x30011004
31
–
30
DRIFT
29
1
28
RX_MPOL
27
–
26
–
25
23
–
22
–
21
–
20
–
19
18
17
15
–
14
–
13
–
12
TX_MPOL
11
–
10
–
7
–
6
–
5
–
4
–
3
2
24
RX_PP
16
RX_PL
9
8
TX_PP
1
0
TX_PL
This register can only be written if the WPEN bit is cleared in the Write Protect Mode Register(if exists).
• DRIFT: Drift compensation
0: The USART can not recover from an important clock drift
1: The USART can recover from clock drift. The 16X clock mode must be enabled.
• RX_MPOL: Receiver Manchester Polarity
0: Logic Zero is coded as a zero-to-one transition, Logic One is coded as a one-to-zero transition.
1: Logic Zero is coded as a one-to-zero transition, Logic One is coded as a zero-to-one transition.
• RX_PP: Receiver Preamble Pattern detected
Table 25-24.
RX_PP
Preamble Pattern default polarity assumed (RX_MPOL field not set)
0
0
ALL_ONE
0
1
ALL_ZERO
1
0
ZERO_ONE
1
1
ONE_ZERO
• RX_PL: Receiver Preamble Length
0: The receiver preamble pattern detection is disabled
1 - 15: The detected preamble length is RX_PL x Bit Period
• TX_MPOL: Transmitter Manchester Polarity
0: Logic Zero is coded as a zero-to-one transition, Logic One is coded as a one-to-zero transition.
1: Logic Zero is coded as a one-to-zero transition, Logic One is coded as a zero-to-one transition.
621
32072C–AVR32–2010/03
AT32UC3A3/A4
• TX_PP: Transmitter Preamble Pattern
Table 25-25.
TX_PP
Preamble Pattern default polarity assumed (TX_MPOL field not set)
0
0
ALL_ONE
0
1
ALL_ZERO
1
0
ZERO_ONE
1
1
ONE_ZERO
• TX_PL: Transmitter Preamble Length
0: The Transmitter Preamble pattern generation is disabled
1 - 15: The Preamble Length is TX_PL x Bit Period
622
32072C–AVR32–2010/03
AT32UC3A3/A4
25.7.16
Name:
LIN Mode Register
LINMR
Access Type:
Read-write
Offset:
0x54
Reset Value:
0x00000000
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
PDCM
15
14
13
12
11
10
9
8
3
CHKDIS
2
PARDIS
1
DLC
7
WKUPTYP
6
FSDIS
5
DLM
4
CHKTYP
0
NACT
• PDCM: Peripheral DMA Controller Mode
•
•
•
•
•
•
•
0: The LIN mode register LINMR is not written by the Peripheral DMA Controller.
1: The LIN mode register LINMR (excepting that bit) is written by the Peripheral DMA Controller.
DLC: Data Length Control
0 - 255: Defines the response data length if DLM=0,in that case the response data length is equal to DLC+1 bytes.
WKUPTYP: Wakeup Signal Type
0: setting the bit LINWKUP in the control register sends a LIN 2.0 wakeup signal.
1: setting the bit LINWKUP in the control register sends a LIN 1.3 wakeup signal.
FSDIS: Frame Slot Mode Disable
0: The Frame Slot Mode is enabled.
1: The Frame Slot Mode is disabled.
DLM: Data Length Mode
0: The response data length is defined by the field DLC of this register.
1: The response data length is defined by the bits 4 and 5 of the Identifier (IDCHR in LINIR).
CHKTYP: Checksum Type
0: LIN 2.0 “Enhanced” Checksum
1: LIN 1.3 “Classic” Checksum
CHKDIS: Checksum Disable
0: In Master node configuration, the checksum is computed and sent automatically. In Slave node configuration, the checksum
is checked automatically.
1: Whatever the node configuration is, the checksum is not computed/sent and it is not checked.
PARDIS: Parity Disable
0: In Master node configuration, the Identifier Parity is computed and sent automatically. In Master node and Slave node
configuration, the parity is checked automatically.
1:Whatever the node configuration is, the Identifier parity is not computed/sent and it is not checked.
623
32072C–AVR32–2010/03
AT32UC3A3/A4
• NACT: LIN Node Action
Table 1.
NACT
Mode Description
0
0
PUBLISH: The USART transmits the response.
0
1
SUBSCRIBE: The USART receives the response.
1
0
IGNORE: The USART does not transmit and does not receive the response.
1
1
Reserved
624
32072C–AVR32–2010/03
AT32UC3A3/A4
25.7.17
Name:
LIN Identifier Register
LINIR
Access Type:
Read-write or Read-only
Offset:
0x58
Reset Value:
0x00000000
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
–
14
–
13
–
12
–
11
–
10
–
9
–
8
–
7
6
5
4
3
2
1
0
IDCHR
• IDCHR: Identifier Character
If MODE=0xA (Master node configuration):
IDCHR is Read-write and its value is the Identifier character to be transmitted.
if MODE=0xB (Slave node configuration):
IDCHR is Read-only and its value is the last Identifier character that has been received.
625
32072C–AVR32–2010/03
AT32UC3A3/A4
25.7.18 Write Protect Mode Register
Register Name:
WPMR
Access Type:
Read-write
Offset:
0xE4
Reset Value:
See Table 25-16
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
—
2
—
1
—
0
WPEN
WPKEY
23
22
21
20
WPKEY
15
14
13
12
WPKEY
7
—
6
—
5
—
4
—
• WPKEY: Write Protect KEY
Should be written at value 0x555341 ("USA" in ASCII). Writing any other value in this field aborts the write operation of the
WPEN bit. Always reads as 0.
• WPEN: Write Protect Enable
0 = Disables the Write Protect if WPKEY corresponds to 0x555341 ("USA" in ASCII).
1 = Enables the Write Protect if WPKEY corresponds to 0x555341 ("USA" in ASCII).
Protects the registers:
• ”Mode Register” on page 605
• ”Baud Rate Generator Register” on page 615
• ”Receiver Time-out Register” on page 616
• ”Transmitter Timeguard Register” on page 617
• ”FI DI RATIO Register” on page 618
• ”IrDA FILTER Register” on page 620
• ”Manchester Configuration Register” on page 621
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25.7.19 Write Protect Status Register
Register Name:
WPSR
Access Type:
Read-only
Offset:
0xE8
Reset Value:
See Table 25-16
31
—
30
—
29
—
28
—
27
—
26
—
25
—
24
—
23
22
21
20
19
18
17
16
11
10
9
8
3
—
2
—
1
—
0
WPVS
WPVSRC
15
14
13
12
WPVSRC
7
—
6
—
5
—
4
—
• WPVSRC: Write Protect Violation Source
When WPVS is active, this field indicates the write-protected register (through address offset or code) in which a write access
has been attempted.
• WPVS: Write Protect Violation Status
0 = No Write Protect Violation has occurred since the last read of the WPSR register.
1 = A Write Protect Violation has occurred since the last read of the WPSR register. If this violation is an unauthorized attempt
to write a protected register, the associated violation is reported into field WPVSRC.
Note:
Reading WPSR automatically clears all fields.
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25.7.20
Version Register
Name:
VERSION
Access Type:
Read-only
Offset:
0xFC
Reset Value:
-
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
18
17
16
15
–
14
–
13
–
12
–
11
9
8
7
6
5
4
1
0
VARIANT
10
VERSION
3
2
VERSION
• VARIANT
Reserved. No functionality associated.
• VERSION
Version of the module. No functionality associated.
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25.8
Module Configuration
The specific configuration for each USART instance is listed in the following tables.The module
bus clocks listed here are connected to the system bus clocks according to the table in the System Bus Clock Connections section.
Table 25-26. Module Configuration
Feature
USART0
USART1
USART2
USART3
SPI Logic
Implemented
Implemented
Implemented
Implemented
LIN Logic
Implemented
Implemented
Implemented
Implemented
Manchester Logic
Not Implemented
Implemented
Not Implemented
Not Implemented
Modem Logic
Not Implemented
Implemented
Not Implemented
Not Implemented
IRDA Logic
Not Implemented
Implemented
Not Implemented
Not Implemented
Fractional
Baudrate
Implemented
Implemented
Implemented
Implemented
ISO7816
Not Implemented
Implemented
Not Implemented
Not Implemented
DIV
8
8
8
8
Receiver Time-out
Counter Size
8-bits
17-bits
8-bits
8-bits
Table 25-27. Module Clock Name
Module name
Clock name
USART0
CLK_USART0
USART1
CLK_USART1
USART2
CLK_USART2
USART3
CLK_USART3
Table 25-28. Register Reset Values
Module name
Reset Value
VERSION
0x00000420
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26. Hi-Speed USB On-The-Go Interface (USBB)
Rev: 3.2.0.5
26.1
Features
• Compatible with the USB 2.0 specification
• Supports High (480Mbit/s), Full (12Mbit/s) and Low (1.5Mbit/s) speed communication and On•
•
•
•
•
•
26.2
The-Go
eight pipes/endpoints
2368 of Embedded Dual-Port RAM (DPRAM) for Pipes/Endpoints
Up to 2 memory banks per Pipe/Endpoint (Not for Control Pipe/Endpoint)
Flexible Pipe/Endpoint configuration and management with dedicated DMA channels
On-Chip UTMI transceiver including Pull-Ups/Pull-downs
On-Chip OTG pad including VBUS analog comparator
Overview
The Universal Serial Bus (USB) MCU device complies with the Universal Serial Bus (USB) 2.0
specification, in all speeds.
Each pipe/endpoint can be configured in one of several transfer types. It can be associated with
one or more banks of a dual-port RAM (DPRAM) used to store the current data payload. If several banks are used (“ping-pong” mode), then one DPRAM bank is read or written by the CPU or
the DMA while the other is read or written by the USBB core. This feature is mandatory for isochronous pipes/endpoints.
Table 26-1 on page 630 describes the hardware configuration of the USB MCU device.
Table 26-1.
Description of USB Pipes/Endpoints
Pipe/Endpoint
Mnemonic
Max. Size
Max. Nb. Banks
DMA
Type
0
PEP0
64 bytes
1
N
Control
1
PEP1
512 bytes
2
Y
Isochronous/Bulk/Interrupt/Control
2
PEP2
512 bytes
2
Y
Isochronous/Bulk/Interrupt/Control
3
PEP3
512 bytes
2
Y
Isochronous/Bulk/Interrupt
4
PEP4
512 bytes
2
Y
Isochronous/Bulk/Interrupt/Control
5
PEP5
512 bytes
2
Y
Isochronous/Bulk/Interrupt/Control
6
PEP6
512 bytes
2
Y
Isochronous/Bulk/Interrupt/Control
7
PEP7
512 bytes
2
Y
Isochronous/Bulk/Interrupt/Control
The theoretical maximal pipe/endpoint configuration (458752) exceeds the real DPRAM size
(2368). The user needs to be aware of this when configuring pipes/endpoints. To fully use the
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2368 of DPRAM, the user could for example use the configuration described inTable 26-2 on
page 631.
Table 26-2.
26.3
Example of Configuration of Pipes/Endpoints Using the Whole DPRAM
Pipe/Endpoint
Mnemonic
Size
Nb. Banks
0
PEP0
64 bytes
1
1
PEP1
512 bytes
2
2
PEP2
512 bytes
2
3
PEP3
256 bytes
1
Block Diagram
The USBB provides a hardware device to interface a USB link to a data flow stored in a dual-port
RAM (DPRAM).
The UTMI transceiver requires an external 12MHz clock as a reference to its internal 480MHz
PLL. The internal 480MHz PLL is used to clock an internal DLL module to recover the USB differential data at 480Mbit/s.
Figure 26-1. USBB Block Diagram
HSB
Slave
Slave
DPRAM
Local HSB
Slave
Interface
HSB Mux
Master
HSB0
PEP
Allocation
DMA
Master
HSB1
OTG
PB
User
Interface
USB
I/O
Controller
2.0 Core
USB_VBUS
USB_ID
USB_VBOF
DMFS
DPFS
UTMI
DMHS
DPHS
GCLK_USBB
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26.4
Application Block Diagram
Depending on the USB operating mode (device-only, reduced-host or OTG mode) and the
power source (bus-powered or self-powered), there are different typical hardware
implementations.
26.4.1
26.4.1.1
Device Mode
Bus-Powered device
Figure 26-2. Bus-Powered Device Application Block Diagram
VDD
3.3 V
Regulator
OTG
USB
I/O
Controller
2.0 Core
USB_VBUS
USB
Connector
USB_ID
VBus
USB_VBOF
ID
DMFS
39 ohms
DPFS
39 ohms
UTMI
DMHS
DPHS
DD+
GND
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26.4.1.2
Self-Powered device
Figure 26-3. Self-powered Device Application Block Diagram
OTG
USB
I/O
Controller
2.0 Core
USB_VBUS
USB
Connector
USB_ID
VBus
USB_VBOF
ID
DMFS
39 ohms
DPFS
39 ohms
UTMI
D+
DMHS
GND
DPHS
26.4.2
D-
Host and OTG Modes
Figure 26-4. Host and OTG Application Block Diagram
VDD
5V DC/DC
Generator
OTG
USB
I/O
Controller
2.0 Core
USB_VBUS
USB
Connector
USB_ID
VBus
USB_VBOF
ID
DMFS
39 ohms
DPFS
39 ohms
UTMI
DMHS
DPHS
DD+
GND
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26.5
I/O Lines Description
Table 26-3.
I/O Lines Description
PIn Name
Pin Description
Type
Active Level
USB_VBOF
USB VBus On/Off: Bus Power Control Port
Output
VBUSPO
USB_VBUS
VBus: Bus Power Measurement Port
DMFS
FS Data -: Full-Speed Differential Data Line - Port
Input/Output
DPFS
FS Data +: Full-Speed Differential Data Line + Port
Input/Output
DMHS
HS Data -: Hi-Speed Differential Data Line - Port
Input/Output
DPHS
HS Data +: Hi-Speed Differential Data Line + Port
Input/Output
USB_ID
USB Identification: Mini Connector Identification Port
Input
Input
Low: Mini-A plug
High Z: Mini-B plug
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26.6
Product Dependencies
In order to use this module, other parts of the system must be configured correctly, as described
below.
26.6.1
I/O Lines
The USB_VBOF and USB_ID pins are multiplexed with I/O Controller lines and may also be
multiplexed with lines of other peripherals. In order to use them with the USB, the user must first
configure the I/O Controller to assign them to their USB peripheral functions.
If USB_ID is used, the I/O Controller must be configured to enable the internal pull-up resistor of
its pin.
If USB_VBOF or USB_ID is not used by the application, the corresponding pin can be used for
other purposes by the I/O Controller or by other peripherals.
26.6.2
Clocks
The clock for the USBB bus interface (CLK_USBB) is generated by the Power Manager. This
clock is enabled at reset, and can be disabled in the Power Manager. It is recommended to disable the USBB before disabling the clock, to avoid freezing the USBB in an undefined state.
The UTMI transceiver needs a 12MHz clock as a clock reference for its internal 480MHz PLL.
Before using the USB, the user must ensure that this 12 MHz clock is available. The 12 MHz
input is connected to a Generic Clock (GCLK_USBB) provided by the Power Manager.
26.6.3
Interrupts
The USBB interrupt request line is connected to the interrupt controller. Using the USBB interrupt requires the interrupt controller to be programmed first.
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26.7
Functional Description
26.7.1
USB General Operation
26.7.1.1
Introduction
After a hardware reset, the USBB is disabled. When enabled, the USBB runs either in device
mode or in host mode according to the ID detection.
If the USB_ID pin is not connected to ground, the USB_ID Pin State bit in the General Status
register (USBSTA.ID) is set (the internal pull-up resistor of the USB_ID pin must be enabled by
the I/O Controller) and device mode is engaged.
The USBSTA.ID bit is cleared when a low level has been detected on the USB_ID pin. Host
mode is then engaged.
26.7.1.2
Power-On and reset
Figure 26-5 on page 636 describes the USBB main states.
Figure 26-5. General States
Macro off:
USBE = 0
Clock stopped:
FRZCLK = 1
USBE = 0
Reset
<any
other
state>
HW
RESET
USBE = 1
ID = 1
USBE = 0
USBE = 1
ID = 0
Device
USBE = 0
Host
After a hardware reset, the USBB is in the Reset state. In this state:
• The macro is disabled. The USBB Enable bit in the General Control register
(USBCON.USBE) is zero.
• The macro clock is stopped in order to minimize power consumption. The Freeze USB Clock
bit in USBCON (USBON.FRZCLK) is set.
• The UTMI is in suspend mode.
• The internal states and registers of the device and host modes are reset.
• The DPRAM is not cleared and is accessible.
• The USBSTA.ID bit and the VBus Level bit in the UBSTA (UBSTA.VBUS) reflect the states of
the USB_ID and USB_VBUS input pins.
• The OTG Pad Enable (OTGPADE) bit, the VBus Polarity (VBUSPO) bit, the FRZCLK bit, the
USBE bit, the USB_ID Pin Enable (UIDE) bit, the USBB Mode (UIMOD) bit in USBCON, and
the Low-Speed Mode Force bit in the Device General Control (UDCON.LS) register can be
written by software, so that the user can program pads and speed before enabling the macro,
but their value is only taken into account once the macro is enabled and unfrozen.
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After writing a one to USBCON.USBE, the USBB enters the Device or the Host mode (according
to the ID detection) in idle state.
The USBB can be disabled at any time by writing a zero to USBCON.USBE. In fact, writing a
zero to USBCON.USBE acts as a hardware reset, except that the OTGPADE, VBUSPO,
FRZCLK, UIDE, UIMOD and, LS bits are not reset.
26.7.1.3
Interrupts
One interrupt vector is assigned to the USB interface. Figure 26-6 on page 638 shows the structure of the USB interrupt system.
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Figure 26-6. Interrupt System
USBSTA.IDTI
USBCON.IDTE
USBSTA.VBUSTI
USBCON.VBUSTE
USBSTA.SRPI
UESTAX.TXINI
USBCON.SRPE
UECONX.TXINE
USBSTA.VBERRI
UECONX.RXOUTE
USBSTA.BCERRI
UECONX.RXSTPE
USBSTA.ROLEEXI
UECONX.UNDERFE
USBSTA.HNPERRI
UECONX.NAKOUTE
USBSTA.STOI
UESTAX.RXOUTI
USBCON.VBERRE
UESTAX.RXSTPI
USB General
Interrupt
USBCON.BCERRE
UESTAX.UNDERFI
USBCON.ROLEEXE
UESTAX.NAKOUTI
USBCON.HNPERRE
UESTAX.HBISOINERRI
USBCON.STOE
UECONX.HBISOINERRE
UESTAX.NAKINI
UECONX.NAKINE
UESTAX.HBISOFLUSHI
UECONX.HBISOFLUSHE
UESTAX.OVERFI
UECONX.OVERFE
UESTAX.STALLEDI
USB Device
Endpoint X
Interrupt
UECONX.STALLEDE
UESTAX.CRCERRI
UECONX.CRCERRE
UESTAX.SHORTPACKET
UDINT.MSOF
UECONX.SHORTPACKETE
UESTAX.DTSEQ=MDATA & UESTAX.RXOUTI
UDINTE.MSOFE
UECONX.MDATAE
UDINT.SUSP
UECONX.DATAXE
UDINT.SOF
UESTAX.DTSEQ=DATAX & UESTAX.RXOUTI
UDINTE.SUSPE
UESTAX.TRANSERR
UDINTE.SOFE
UDINT.EORST
UECONX.TRANSERRE
UESTAX.NBUSYBK
USB
Interrupt
UDINTE.EORSTE
UDINT.WAKEUP
UECONX.NBUSYBKE
UDINTE.WAKEUPE
UDINT.EORSM
USB Device
Interrupt
UDINTE.EORSME
UDINT.UPRSM
UDINTE.UPRSME
UDDMAX_STATUS.EOT_STA
UDINT.EPXINT
UDDMAX_CONTROL.EOT_IRQ_EN
UDINTE.EPXINTE
UDDMAX_STATUS.EOCH_BUFF_STA
UDINT.DMAXINT
UDDMAX_CONTROL.EOBUFF_IRQ_EN
UDDMAX_STATUS.DESC_LD_STA
UDDMAX_CONTROL.DESC_LD_IRQ_EN
USB Device
DMA Channel X
Interrupt
UDINTE.DMAXINTE
UPSTAX.RXINI
UPCONX.RXINE
UPSTAX.TXOUTI
UPCONX.TXOUTE
UPSTAX.TXSTPI
UPCONX.TXSTPE
UPSTAX.UNDERFI
UPCONX.UNDERFIE
UPSTAX.PERRI
UPCONX.PERRE
UHINT.DCONNI
UPSTAX.NAKEDI
UHINTE.DCONNIE
UPCONX.NAKEDE
UHINT.DDISCI
UPCONX.OVERFIE
UHINT.RSTI
UPSTAX.OVERFI
UHINTE.DDISCIE
UPSTAX.RXSTALLDI
UHINTE.RSTIE
UPCONX.RXSTALLDE
UPSTAX.CRCERRI
UPCONX.CRCERRE
UPSTAX.SHORTPACKETI
USB Host
Pipe X
Interrupt
UHINT.RSMEDI
UHINTE.RSMEDIE
UHINT.RXRSMI
UHINTE.RXRSMIE
UPCONX.SHORTPACKETIE
USB Host
Interrupt
UHINT.HSOFI
UPSTAX.NBUSYBK
UHINTE.HSOFIE
UPCONX.NBUSYBKE
UHINT.HWUPI
UHINTE.HWUPIE
UHDMAX_STATUS.EOT_STA
UHINT.PXINT
UHDMAX_CONTROL.EOT_IRQ_EN
UHDMAX_STATUS.EOCH_BUFF_STA
UHDMAX_CONTROL.EOBUFF_IRQ_EN
UHDMAX_STATUS.DESC_LD_STA
UHDMAX_CONTROL.DESC_LD_IRQ_EN
UHINTE.PXINTE
UHINT.DMAXINT
USB Host
DMA Channel X
Interrupt
UHINTE.DMAXINTE
Asynchronous interrupt source
See Section 26.7.2.19 and Section 26.7.3.13 for further details about device and host interrupts.
There are two kinds of general interrupts: processing, i.e. their generation is part of the normal
processing, and exception, i.e. errors (not related to CPU exceptions).
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The processing general interrupts are:
• The ID Transition Interrupt (IDTI)
• The VBus Transition Interrupt (VBUSTI)
• The SRP Interrupt (SRPI)
• The Role Exchange Interrupt (ROLEEXI)
The exception general interrupts are:
• The VBus Error Interrupt (VBERRI)
• The B-Connection Error Interrupt (BCERRI)
• The HNP Error Interrupt (HNPERRI)
• The Suspend Time-Out Interrupt (STOI)
26.7.1.4
MCU Power modes
•Run mode
In this mode, all MCU clocks can run, including the USB clock.
•Idle mode
In this mode, the CPU is halted, i.e. the CPU clock is stopped. The Idle mode is entered whatever the state of the USBB. The MCU wakes up on any USB interrupt.
•Frozen mode
Same as the Idle mode, except that the HSB module is stopped, so the USB DMA, which is an
HSB master, can not be used. Moreover, the USB DMA must be stopped before entering this
sleep mode in order to avoid erratic behavior. The MCU wakes up on any USB interrupt.
•Standby, Stop, DeepStop and Static modes
Same as the Frozen mode, except that the USB generic clock and other clocks are stopped, so
the USB macro is frozen. Only the asynchronous USB interrupt sources can wake up the MCU
in these modes. The Power Manager (PM) may have to be configured to enable asynchronous
wake up from USB.
•USB clock frozen
In the run, idle and frozen MCU modes, the USBB can be frozen when the USB line is in the suspend mode, by writing a one to the FRZCLK bit, what reduces power consumption.
In this case, it is still possible to access the following elements, but only in Run mode:
• The OTGPADE, VBUSPO, FRZCLK, USBE, UIDE, UIMOD and LS bits in the USBCON
register
• The DPRAM (through the USB Pipe/Endpoint n FIFO Data (USBFIFOnDATA) registers, but
not through USB bus transfers which are frozen)
Moreover, when FRZCLK is written to one, only the asynchronous interrupt sources may trigger
the USB interrupt:
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• The ID Transition Interrupt (IDTI)
• The VBus Transition Interrupt (VBUSTI)
• The Wake-up Interrupt (WAKEUP)
• The Host Wake-up Interrupt (HWUPI)
•USB Suspend mode
In peripheral mode, the Suspend Interrupt bit in the Device Global Interrupt register
(UDINT.SUSP)indicates that the USB line is in the suspend mode. In this case, the transceiver
is automatically set in suspend mode to reduce the consumption.The 480MHz internal PLL is
stopped. The USBSTA.CLKUSABLE bit is cleared.
26.7.1.5
Speed control
•Device mode
When the USB interface is in device mode, the speed selection (full-speed or high-speed) is performed automatically by the USBB during the USB reset according to the host speed capability.
At the end of the USB reset, the USBB enables or disables high-speed terminations and pull-up.
It is possible to restraint the USBB to full-speed or low-speed mode by handling the LS and the
Speed Configuration (SPDCONF) bits in UDCON.
•Host mode
When the USB interface is in host mode, internal pull-down resistors are connected on both D+
and D- and the interface detects the speed of the connected device, which is reflected by the
Speed Status (SPEED) field in USBSTA.
26.7.1.6
DPRAM management
Pipes and endpoints can only be allocated in ascending order (from the pipe/endpoint 0 to the
last pipe/endpoint to be allocated). The user shall therefore configure them in the same order.
The allocation of a pipe/endpoint n starts when the Endpoint Memory Allocate bit in the Endpoint
n Configuration register (UECFGn.ALLOC) is written to one. Then, the hardware allocates a
memory area in the DPRAM and inserts it between the n-1 and n+1 pipes/endpoints. The n+1
pipe/endpoint memory window slides up and its data is lost. Note that the following pipe/endpoint memory windows (from n+2) do not slide.
Disabling a pipe, by writing a zero to the Pipe n Enable bit in the Pipe Enable/Reset register
(UPRST.PENn), or disabling an endpoint, by writing a zero to the Endpoint n Enable bit in the
Endpoint Enable/Reset register (UERST.EPENn), resets neither the UECFGn.ALLOC bit nor its
configuration (the Pipe Banks (PBK) field, the Pipe Size (PSIZE) field, the Pipe Token (PTOKEN) field, the Pipe Type (PTYPE) field, the Pipe Endpoint Number (PEPNUM) field, and the
Pipe Interrupt Request Frequency (INTFRQ) field in the Pipe n Configuration (UPCFGn) register/the Endpoint Banks (EPBK) field, the Endpoint Size (EPSIZE) field, the Endpoint Direction
(EPDIR) field, and the Endpoint Type (EPTYPE) field in UECFGn).
To free its memory, the user shall write a zero to the UECFGn.ALLOC bit. The n+1 pipe/endpoint memory window then slides down and its data is lost. Note that the following pipe/endpoint
memory windows (from n+2) does not slide.
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Figure 26-7 on page 641 illustrates the allocation and reorganization of the DPRAM in a typical
example.
Figure 26-7. Allocation and Reorganization of the DPRAM
Free Memory
Free Memory
Free Memory
Free Memory
PEP5
PEP5
PEP5
PEP5
PEP4
PEP4
PEP4
PEP3
PEP3
(ALLOC stays at 1)
PEP4
PEP3 (larger size)
PEP2
PEP2
PEP2
PEP2
PEP1
PEP1
PEP1
PEP1
PEP0
PEP0
PEP0
PEP0
U(P/E)RST.(E)PENn = 1
U(P/E)CFGn.ALLOC = 1
Pipes/Endpoints 0..5
Activated
U(P/E)RST.(E)PEN3 = 0
Pipe/Endpoint 3
Disabled
Conflict
PEP4 Lost Memory
U(P/E)CFG3.ALLOC = 0
Pipe/Endpoint 3
Memory Freed
U(P/E)RST.(E)PEN3 = 1
U(P/E)CFG3.ALLOC = 1
Pipe/Endpoint 3
Activated
1. The pipes/endpoints 0 to 5 are enabled, configured and allocated in ascending order.
Each pipe/endpoint then owns a memory area in the DPRAM.
2. The pipe/endpoint 3 is disabled, but its memory is kept allocated by the controller.
3. In order to free its memory, its ALLOC bit is written to zero. The pipe/endpoint 4 memory window slides down, but the pipe/endpoint 5 does not move.
4. If the user chooses to reconfigure the pipe/endpoint 3 with a larger size, the controller
allocates a memory area after the pipe/endpoint 2 memory area and automatically
slides up the pipe/endpoint 4 memory window. The pipe/endpoint 5 does not move and
a memory conflict appears as the memory windows of the pipes/endpoints 4 and 5
overlap. The data of these pipes/endpoints is potentially lost.
Note that:
• There is no way the data of the pipe/endpoint 0 can be lost (except if it is de-allocated) as
memory allocation and de-allocation may affect only higher pipes/endpoints.
• Deactivating then reactivating a same pipe/endpoint with the same configuration only
modifies temporarily the controller DPRAM pointer and size for this pipe/endpoint, but
nothing changes in the DPRAM, so higher endpoints seem to not have been moved and their
data is preserved as far as nothing has been written or received into them while changing the
allocation state of the first pipe/endpoint.
• When the user write a one to the ALLOC bit, the Configuration OK Status bit in the Endpoint
n Status register (UESTAn.CFGOK) is set only if the configured size and number of banks
are correct compared to their maximal allowed values for the endpoint and to the maximal
FIFO size (i.e. the DPRAM size), so the value of CFGOK does not consider memory
allocation conflicts.
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26.7.1.7
Pad Suspend
Figure 26-8 on page 642 shows the pad behavior.
Figure 26-8. Pad Behavior
USBE = 1
& DETACH = 0
& Suspend
Idle
USBE = 0
| DETACH = 1
| Suspend
Active
• In the Idle state, the pad is put in low power consumption mode, i.e., the differential receiver
of the USB pad is off, and internal pull-down with strong value(15K) are set in both DP/DM to
avoid floating lines.
• In the Active state, the pad is working.
Figure 26-9 on page 642 illustrates the pad events leading to a PAD state change.
Figure 26-9. Pad Events
SUSP
Suspend detected
WAKEUP
Cleared on wake-up
Wake-up detected
Cleared by software to acknowledge the interrupt
PAD State
Active
Idle
Active
The SUSP bit is set and the Wake-Up Interrupt (WAKEUP) bit in UDINT is cleared when a USB
“Suspend” state has been detected on the USB bus. This event automatically puts the USB pad
in the Idle state. The detection of a non-idle event sets WAKEUP, clears SUSP and wakes up
the USB pad.
Moreover, the pad goes to the Idle state if the macro is disabled or if the DETACH bit is written to
one. It returns to the Active state when USBE is written to one and DETACH is written to zero.
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26.7.1.8
Table 26-4.
Customizing of OTG timers
It is possible to refine some OTG timers thanks to the Timer Page (TIMPAGE) and Timer Value
(TIMVALUE) fields in USBCON, as shown by Table 26-4 on page 643.
Customizing of OTG Timers
TIMVALUE
TIMPAGE
Note:
0b00
AWaitVrise Time-Out
(see OTG Standard(1)
Section 6.6.5.1)
0b01
VbBusPulsing Time-Out
(see OTG Standard(1)
Section5.3.4)
0b10
PdTmOutCnt Time-Out
(see OTG Standard(1)
Section 5.3.2)
0b11
SRPDetTmOut Time-Out
(see OTG Standard(1)
Section 5.3.3)
00b
20 ms
15 ms
93 ms
10 µs
01b
50 ms
23 ms
105 ms
100 µs
10b
70 ms
31 ms
118 ms
1 ms
11b
100 ms
40 ms
131 ms
11 ms
1. “On-The-Go Supplement to the USB 2.0 Specification Revision 1.0a”.
TIMPAGE is used to select the OTG timer to access while TIMVALUE indicates the time-out
value of the selected timer.
TIMPAGE and TIMVALUE can be read or written. Before writing them, the user shall unlock
write accesses by writing a one to the Timer Access Unlock (UNLOCK) bit in USBCON. This is
not required for read accesses, except before accessing TIMPAGE if it has to be written in order
to read the TIMVALUE field of another OTG timer.
26.7.1.9
Plug-In detection
The USB connection is detected from the USB_VBUS pad. Figure 26-10 on page 643 shows the
architecture of the plug-in detector.
Figure 26-10. Plug-In Detection Input Block Diagram
VDD
RPU
VBus_pulsing
USB_VBUS
Session_valid
RPD
Va_Vbus_valid
Logic
VBUS
VBUSTI
USBSTA
USBSTA
VBus_discharge
GND
Pad Logic
The control logic of the USB_VBUS pad outputs two signals:
• The Session_valid signal is high when the voltage on the USB_VBUS pad is higher than or
equal to 1.4V.
• The Va_Vbus_valid signal is high when the voltage on the USB_VBUS pad is higher than or
equal to 4.4V.
In device mode, the USBSTA.VBUS bit follows the Session_valid comparator output:
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• It is set when the voltage on the USB_VBUS pad is higher than or equal to 1.4V.
• It is cleared when the voltage on the VBUS pad is lower than 1.4V.
In host mode, the USBSTA.VBUS bit follows an hysteresis based on Session_valid and
Va_Vbus_valid:
• It is set when the voltage on the USB_VBUS pad is higher than or equal to 4.4V.
• It is cleared when the voltage on the USB_VBUS pad is lower than 1.4V.
The VBus Transition interrupt (VBUSTI) bit in USBSTA is set on each transition of the USBSTA.VBUS bit.
The USBSTA.VBUS bit is effective whether the USBB is enabled or not.
26.7.1.10
ID detection
Figure 26-11 on page 644 shows how the ID transitions are detected.
Figure 26-11. ID Detection Input Block Diagram
RPU
VDD
1
USB_ID
0
UIMOD
ID
IDTI
USBSTA
USBSTA
USBCON
UIDE
USBCON
I/O Controller
The USB mode (device or host) can be either detected from the USB_ID pin or software
selected by writing to the UIMOD bit, according to the UIDE bit. This allows the USB_ID pin to be
used as a general purpose I/O pin even when the USB interface is enabled.
By default, the USB_ID pin is selected (UIDE is written to one) and the USBB is in device mode
(UBSTA.ID is one), what corresponds to the case where no Mini-A plug is connected, i.e. no
plug or a Mini-B plug is connected and the USB_ID pin is kept high by the internal pull-up resistor from the I/O Controller (which must be enabled if USB_ID is used).
The ID Transition Interrupt (IDTI) bit in USBSTA is set on each transition of the ID bit, i.e. when a
Mini-A plug (host mode) is connected or disconnected. This does not occur when a Mini-B plug
(device mode) is connected or disconnected.
The USBSTA.ID bit is effective whether the USBB is enabled or not.
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26.7.2
26.7.2.1
USB Device Operation
Introduction
In device mode, the USBB supports hi- full- and low-speed data transfers.
In addition to the default control endpoint, seven endpoints are provided, which can be configured with the types isochronous, bulk or interrupt, as described in .Table 26-1 on page 630.
The device mode starts in the Idle state, so the pad consumption is reduced to the minimum.
26.7.2.2
Power-On and reset
Figure 26-12 on page 645 describes the USBB device mode main states.
Figure 26-12. Device Mode States
USBE = 0
| ID = 0
<any
other
state>
USBE = 0
| ID = 0
Reset
Idle
USBE = 1
& ID = 1
HW
RESET
After a hardware reset, the USBB device mode is in the Reset state. In this state:
• The macro clock is stopped in order to minimize power consumption (FRZCLK is written to
one).
• The internal registers of the device mode are reset.
• The endpoint banks are de-allocated.
• Neither D+ nor D- is pulled up (DETACH is written to one).
D+ or D- will be pulled up according to the selected speed as soon as the DETACH bit is written
to zero and VBus is present. See “Device mode” for further details.
When the USBB is enabled (USBE is written to one) in device mode (ID is one), its device mode
state goes to the Idle state with minimal power consumption. This does not require the USB
clock to be activated.
The USBB device mode can be disabled and reset at any time by disabling the USBB (by writing
a zero to USBE) or when host mode is engaged (ID is zero).
26.7.2.3
USB reset
The USB bus reset is managed by hardware. It is initiated by a connected host.
When a USB reset is detected on the USB line, the following operations are performed by the
controller:
• All the endpoints are disabled, except the default control endpoint.
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• The default control endpoint is reset (see Section 26.7.2.4 for more details).
• The data toggle sequence of the default control endpoint is cleared.
• At the end of the reset process, the End of Reset (EORST) bit in UDINT interrupt is set.
• During a reset, the USBB automatically switches to the Hi-Speed mode if the host is HiSpeed capable (the reset is called a Hi-Speed reset). The user should observe the
USBSTA.SPEED field to know the speed running at the end of the reset (EORST is one).
26.7.2.4
Endpoint reset
An endpoint can be reset at any time by writing a one to the Endpoint n Reset (EPRSTn) bit in
the UERST register. This is recommended before using an endpoint upon hardware reset or
when a USB bus reset has been received. This resets:
• The internal state machine of this endpoint.
• The receive and transmit bank FIFO counters.
• All the registers of this endpoint (UECFGn, UESTAn, the Endpoint n Control (UECONn)
register), except its configuration (ALLOC, EPBK, EPSIZE, EPDIR, EPTYPE) and the Data
Toggle Sequence (DTSEQ) field of the UESTAn register.
Note that the interrupt sources located in the UESTAn register are not cleared when a USB bus
reset has been received.
The endpoint configuration remains active and the endpoint is still enabled.
The endpoint reset may be associated with a clear of the data toggle sequence as an answer to
the CLEAR_FEATURE USB request. This can be achieved by writing a one to the Reset Data
Toggle Set bit in the Endpoint n Control Set register (UECONnSET.RSTDTS).(This will set the
Reset Data Toggle (RSTD) bit in UECONn).
In the end, the user has to write a zero to the EPRSTn bit to complete the reset operation and to
start using the FIFO.
26.7.2.5
Endpoint activation
The endpoint is maintained inactive and reset (see Section 26.7.2.4 for more details) as long as
it is disabled (EPENn is written to zero). DTSEQ is also reset.
The algorithm represented on Figure 26-13 on page 647 must be followed in order to activate an
endpoint.
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Figure 26-13. Endpoint Activation Algorithm
Endpoint
Activation
Enable the endpoint.
EPENn = 1
Configure the endpoint:
- type
- direction
- size
- number of banks
Allocate the configured DPRAM banks.
UECFGn
EPTYPE
EPDIR
EPSIZE
EPBK
ALLOC
CFGOK ==
1?
Yes
Test if the endpoint configuration is correct.
No
Endpoint
Activated
ERROR
As long as the endpoint is not correctly configured (CFGOK is zero), the controller does not
acknowledge the packets sent by the host to this endpoint.
The CFGOK bit is set only if the configured size and number of banks are correct compared to
their maximal allowed values for the endpoint (see Table 26-1 on page 630) and to the maximal
FIFO size (i.e. the DPRAM size).
See Section 26.7.1.6 for more details about DPRAM management.
26.7.2.6
Address setup
The USB device address is set up according to the USB protocol.
• After all kinds of resets, the USB device address is 0.
• The host starts a SETUP transaction with a SET_ADDRESS(addr) request.
• The user write this address to the USB Address (UADD) field in UDCON, and write a zero to
the Address Enable (ADDEN) bit in UDCON, so the actual address is still 0.
• The user sends a zero-length IN packet from the control endpoint.
• The user enables the recorded USB device address by writing a one to ADDEN.
Once the USB device address is configured, the controller filters the packets to only accept
those targeting the address stored in UADD.
UADD and ADDEN shall not be written all at once.
UADD and ADDEN are cleared:
• On a hardware reset.
• When the USBB is disabled (USBE written to zero).
• When a USB reset is detected.
When UADD or ADDEN is cleared, the default device address 0 is used.
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26.7.2.7
Suspend and wake-up
When an idle USB bus state has been detected for 3 ms, the controller set the Suspend (SUSP)
interrupt bit in UDINT. The user may then write a one to the FRZCLK bit to reduce power consumption. The MCU can also enter the Idle or Frozen sleep mode to lower again power
consumption.
To recover from the Suspend mode, the user shall wait for the Wake-Up (WAKEUP) interrupt bit,
which is set when a non-idle event is detected, then write a zero to FRZCLK.
As the WAKEUP interrupt bit in UDINT is set when a non-idle event is detected, it can occur
whether the controller is in the Suspend mode or not. The SUSP and WAKEUP interrupts are
thus independent of each other except that one bit is cleared when the other is set.
26.7.2.8
Detach
The reset value of the DETACH bit is one.
It is possible to initiate a device re-enumeration simply by writing a one then a zero to DETACH.
DETACH acts on the pull-up connections of the D+ and D- pads. See “Device mode” for further
details.
26.7.2.9
Remote wake-up
The Remote Wake-Up request (also known as Upstream Resume) is the only one the device
may send on its own initiative, but the device should have beforehand been allowed to by a
DEVICE_REMOTE_WAKEUP request from the host.
• First, the USBB must have detected a “Suspend” state on the bus, i.e. the Remote Wake-Up
request can only be sent after a SUSP interrupt has been set.
• The user may then write a one to the Remote Wake-Up (RMWKUP) bit in UDCON to send an
upstream resume to the host for a remote wake-up. This will automatically be done by the
controller after 5ms of inactivity on the USB bus.
• When the controller sends the upstream resume, the Upstream Resume (UPRSM) interrupt
is set and SUSP is cleared.
• RMWKUP is cleared at the end of the upstream resume.
• If the controller detects a valid “End of Resume” signal from the host, the End of Resume
(EORSM) interrupt is set.
26.7.2.10
STALL request
For each endpoint, the STALL management is performed using:
• The STALL Request (STALLRQ) bit in UECONn to initiate a STALL request.
• The STALLed Interrupt (STALLEDI) bit in UESTAn is set when a STALL handshake has been
sent.
To answer the next request with a STALL handshake, STALLRQ has to be set by writing a one
to the STALL Request Set (STALLRQS) bit. All following requests will be discarded (RXOUTI,
etc. will not be set) and handshaked with a STALL until the STALLRQ bit is cleared, what is
done when a new SETUP packet is received (for control endpoints) or when the STALL Request
Clear (STALLRQC) bit is written to one.
Each time a STALL handshake is sent, the STALLEDI bit is set by the USBB and the EPnINT
interrupt is set.
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•Special considerations for control endpoints
If a SETUP packet is received into a control endpoint for which a STALL is requested, the
Received SETUP Interrupt (RXSTPI) bit in UESTAn is set and STALLRQ and STALLEDI are
cleared. The SETUP has to be ACKed.
This management simplifies the enumeration process management. If a command is not supported or contains an error, the user requests a STALL and can return to the main task, waiting
for the next SETUP request.
•STALL handshake and retry mechanism
The retry mechanism has priority over the STALL handshake. A STALL handshake is sent if the
STALLRQ bit is set and if there is no retry required.
26.7.2.11
Management of control endpoints
•Overview
A SETUP request is always ACKed. When a new SETUP packet is received, the RXSTPI is set,
but not the Received OUT Data Interrupt (RXOUTI) bit.
The FIFO Control (FIFOCON) bit in UECONn and the Read/Write Allowed (RWALL) bit in
UESTAn are irrelevant for control endpoints. The user shall therefore never use them on these
endpoints. When read, their value are always zero.
Control endpoints are managed using:
• The RXSTPI bit which is set when a new SETUP packet is received and which shall be
cleared by firmware to acknowledge the packet and to free the bank.
• The RXOUTI bit which is set when a new OUT packet is received and which shall be cleared
by firmware to acknowledge the packet and to free the bank.
• The Transmitted IN Data Interrupt (TXINI) bit which is set when the current bank is ready to
accept a new IN packet and which shall be cleared by firmware to send the packet.
•Control write
Figure 26-14 on page 650 shows a control write transaction. During the status stage, the controller will not necessarily send a NAK on the first IN token:
• If the user knows the exact number of descriptor bytes that must be read, it can then
anticipate the status stage and send a zero-length packet after the next IN token.
• Or it can read the bytes and wait for the NAKed IN Interrupt (NAKINI) which tells that all the
bytes have been sent by the host and that the transaction is now in the status stage.
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Figure 26-14. Control Write
SETUP
USB Bus
DATA
SETUP
OUT
STATUS
OUT
IN
IN
NAK
RXSTPI
HW
SW
RXOUTI
HW
SW
HW
SW
TXINI
SW
•Control read
Figure 26-15 on page 650 shows a control read transaction. The USBB has to manage the
simultaneous write requests from the CPU and the USB host.
Figure 26-15. Control Read
SETUP
USB Bus
RXSTPI
DATA
SETUP
IN
STATUS
IN
OUT
OUT
NAK
HW
SW
RXOUTI
HW
TXINI
SW
HW
SW
SW
Wr Enable
HOST
Wr Enable
CPU
A NAK handshake is always generated on the first status stage command.
When the controller detects the status stage, all the data written by the CPU are lost and clearing TXINI has no effect.
The user checks if the transmission or the reception is complete.
The OUT retry is always ACKed. This reception sets RXOUTI and TXINI. Handle this with the
following software algorithm:
set TXINI
wait for RXOUTI OR TXINI
if RXOUTI, then clear bit and return
if TXINI, then continue
Once the OUT status stage has been received, the USBB waits for a SETUP request. The
SETUP request has priority over any other request and has to be ACKed. This means that any
other bit should be cleared and the FIFO reset when a SETUP is received.
The user has to take care of the fact that the byte counter is reset when a zero-length OUT
packet is received.
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26.7.2.12
Management of IN endpoints
•Overview
IN packets are sent by the USB device controller upon IN requests from the host. All the data
can be written which acknowledges or not the bank when it is full.
The endpoint must be configured first.
The TXINI bit is set at the same time as FIFOCON when the current bank is free. This triggers
an EPnINT interrupt if the Transmitted IN Data Interrupt Enable (TXINE) bit in UECONn is one.
TXINI shall be cleared by software (by writing a one to the Transmitted IN Data Interrupt Enable
Clear bit in the Endpoint n Control Clear register (UECONnCLR.TXINIC)) to acknowledge the
interrupt, what has no effect on the endpoint FIFO.
The user then writes into the FIFO and write a one to the FIFO Control Clear (FIFOCONC) bit in
UECONnCLR to clear the FIFOCON bit. This allows the USBB to send the data. If the IN endpoint is composed of multiple banks, this also switches to the next bank. The TXINI and
FIFOCON bits are updated in accordance with the status of the next bank.
TXINI shall always be cleared before clearing FIFOCON.
The RWALL bit is set when the current bank is not full, i.e. the software can write further data
into the FIFO.
Figure 26-16. Example of an IN Endpoint with 1 Data Bank
NAK
IN
DATA
(bank 0)
ACK
IN
HW
TXINI
SW
SW
write data to CPU
BANK 0
FIFOCON
write data to CPU
BANK 0
SW
SW
Figure 26-17. Example of an IN Endpoint with 2 Data Banks
DATA
(bank 0)
IN
ACK
IN
DATA
(bank 1)
ACK
HW
TXINI
FIFOCON
SW
write data to CPU
BANK 0
SW
SW
write data to CPU
BANK 1
SW
SW
write data to CPU
BANK0
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•Detailed description
The data is written, following the next flow:
• When the bank is empty, TXINI and FIFOCON are set, what triggers an EPnINT interrupt if
TXINE is one.
• The user acknowledges the interrupt by clearing TXINI.
• The user writes the data into the current bank by using the USB Pipe/Endpoint nFIFO Data
(USBFIFOnDATA) register, until all the data frame is written or the bank is full (in which case
RWALL is cleared and the Byte Count (BYCT) field in UESTAn reaches the endpoint size).
• The user allows the controller to send the bank and switches to the next bank (if any) by
clearing FIFOCON.
If the endpoint uses several banks, the current one can be written while the previous one is
being read by the host. Then, when the user clears FIFOCON, the following bank may already
be free and TXINI is set immediately.
An “Abort” stage can be produced when a zero-length OUT packet is received during an IN
stage of a control or isochronous IN transaction. The Kill IN Bank (KILLBK) bit in UECONn is
used to kill the last written bank. The best way to manage this abort is to apply the algorithm represented on Figure 26-18 on page 652.
Figure 26-18. Abort Algorithm
Endpoint
Abort
Disable the TXINI interrupt.
TXINEC = 1
NBUSYBK
== 0?
Yes
Abort is based on the fact
that no bank is busy, i.e.,
that nothing has to be sent
No
EPRSTn = 1
KILLBKS = 1
Yes
KILLBK
== 1?
Kill the last written bank.
Wait for the end of the
procedure
No
Abort Done
26.7.2.13
Management of OUT endpoints
•Overview
OUT packets are sent by the host. All the data can be read which acknowledges or not the bank
when it is empty.
The endpoint must be configured first.
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The RXOUTI bit is set at the same time as FIFOCON when the current bank is full. This triggers
an EPnINT interrupt if the Received OUT Data Interrupt Enable (RXOUTE) bit in UECONn is
one.
RXOUTI shall be cleared by software (by writing a one to the Received OUT Data Interrupt Clear
(RXOUTIC) bit) to acknowledge the interrupt, what has no effect on the endpoint FIFO.
The user then reads from the FIFO and clears the FIFOCON bit to free the bank. If the OUT endpoint is composed of multiple banks, this also switches to the next bank. The RXOUTI and
FIFOCON bits are updated in accordance with the status of the next bank.
RXOUTI shall always be cleared before clearing FIFOCON.
The RWALL bit is set when the current bank is not empty, i.e. the software can read further data
from the FIFO.
Figure 26-19. Example of an OUT Endpoint with one Data Bank
DATA
(bank 0)
OUT
NAK
ACK
OUT
DATA
(bank 0)
ACK
HW
RXOUTI
HW
SW
SW
read data from CPU
BANK 0
FIFOCON
read data from CPU
BANK 0
SW
Figure 26-20. Example of an OUT Endpoint with two Data Banks
DATA
(bank 0)
OUT
ACK
OUT
DATA
(bank 1)
HW
RXOUTI
ACK
HW
SW
SW
read data from CPU
BANK 0
FIFOCON
SW
read data from CPU
BANK 1
•Detailed description
The data is read, following the next flow:
• When the bank is full, RXOUTI and FIFOCON are set, what triggers an EPnINT interrupt if
RXOUTE is one.
• The user acknowledges the interrupt by writing a one to RXOUTIC in order to clear RXOUTI.
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• The user can read the byte count of the current bank from BYCT to know how many bytes to
read, rather than polling RWALL.
• The user reads the data from the current bank by using the USBFIFOnDATA register, until all
the expected data frame is read or the bank is empty (in which case RWALL is cleared and
BYCT reaches zero).
• The user frees the bank and switches to the next bank (if any) by clearing FIFOCON.
If the endpoint uses several banks, the current one can be read while the following one is being
written by the host. Then, when the user clears FIFOCON, the following bank may already be
ready and RXOUTI is set immediately.
In Hi-Speed mode, the PING and NYET protocol is handled by the USBB. For single bank, a
NYET handshake is always sent to the host (on Bulk-out transaction) to indicate that the current
packet is acknowledged but there is no room for the next one. For double bank, the USBB
responds to the OUT/DATA transaction with an ACK handshake when the endpoint accepted
the data successfully and has room for another data payload (the second bank is free).
26.7.2.14
Underflow
This error exists only for isochronous IN/OUT endpoints. It set the Underflow Interrupt
(UNDERFI) bit in UESTAn, what triggers an EPnINT interrupt if the Underflow Interrupt Enable
(UNDERFE) bit is one.
An underflow can occur during IN stage if the host attempts to read from an empty bank. A zerolength packet is then automatically sent by the USBB.
An underflow can not occur during OUT stage on a CPU action, since the user may read only if
the bank is not empty (RXOUTI is one or RWALL is one).
An underflow can also occur during OUT stage if the host sends a packet while the bank is
already full. Typically, the CPU is not fast enough. The packet is lost.
An underflow can not occur during IN stage on a CPU action, since the user may write only if the
bank is not full (TXINI is one or RWALL is one).
26.7.2.15
Overflow
This error exists for all endpoint types. It set the Overflow interrupt (OVERFI) bit in UESTAn,
what triggers an EPnINT interrupt if the Overflow Interrupt Enable (OVERFE) bit is one.
An overflow can occur during OUT stage if the host attempts to write into a bank that is too small
for the packet. The packet is acknowledged and the RXOUTI bit is set as if no overflow had
occurred. The bank is filled with all the first bytes of the packet that fit in.
An overflow can not occur during IN stage on a CPU action, since the user may write only if the
bank is not full (TXINI is one or RWALL is one).
26.7.2.16
HB IsoIn error
This error exists only for high-bandwidth isochronous IN endpoints.
At the end of the micro-frame, if at least one packet has been sent to the host, if less banks than
expected has been validated (by clearing the FIFOCON) for this micro-frame, it set the
HBISOINERRORI bit in UESTAn, what triggers an EPnINT interrupt if the High Bandwidth Isochronous IN Error Interrupt Enable (HBISOINERRORE) bit is one.
For instance, if the Number of Transaction per MicroFrame for Isochronous Endpoint
(NBTRANS field in UECFGn is three (three transactions per micro-frame), only two banks are
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filled by the CPU (three expected) for the current micro-frame. Then, the HBISOINERRI interrupt
is generated at the end of the micro-frame. Note that an UNDERFI interrupt is also generated
(with an automatic zero-length-packet), except in the case of a missing IN token.
26.7.2.17
HB IsoFlush
This error exists only for high-bandwidth isochronous IN endpoints.
At the end of the micro-frame, if at least one packet has been sent to the host, if there is missing
IN token during this micro-frame, the bank(s) destined to this micro-frame is/are flushed out to
ensure a good data synchronization between the host and the device.
For instance, if NBTRANS is three (three transactions per micro-frame), if only the first IN token
(among 3) is well received by the USBB, then the two last banks will be discarded.
26.7.2.18
CRC error
This error exists only for isochronous OUT endpoints. It set the CRC Error Interrupt (CRCERRI)
bit in UESTAn, what triggers an EPnINT interrupt if the CRC Error Interrupt Enable (CRCERRE)
bit is one.
A CRC error can occur during OUT stage if the USBB detects a corrupted received packet. The
OUT packet is stored in the bank as if no CRC error had occurred (RXOUTI is set).
26.7.2.19
Interrupts
See the structure of the USB device interrupt system on Figure 26-6 on page 638.
There are two kinds of device interrupts: processing, i.e. their generation is part of the normal
processing, and exception, i.e. errors (not related to CPU exceptions).
•Global interrupts
The processing device global interrupts are:
• The Suspend (SUSP) interrupt
• The Start of Frame (SOF) interrupt with no frame number CRC error (the Frame Number
CRC Error (FNCERR) bit in the Device Frame Number (UDFNUM) register is zero)
• The Micro Start of Frame (MSOF) interrupt with no CRC error.
• The End of Reset (EORST) interrupt
• The Wake-Up (WAKEUP) interrupt
• The End of Resume (EORSM) interrupt
• The Upstream Resume (UPRSM) interrupt
• The Endpoint n (EPnINT) interrupt
• The DMA Channel n (DMAnINT) interrupt
The exception device global interrupts are:
• The Start of Frame (SOF) interrupt with a frame number CRC error (FNCERR is one)
• The Micro Start of Frame (MSOF) interrupt with a CRC error
•Endpoint interrupts
The processing device endpoint interrupts are:
• The Transmitted IN Data Interrupt (TXINI)
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• The Received OUT Data Interrupt (RXOUTI)
• The Received SETUP Interrupt (RXSTPI)
• The Short Packet (SHORTPACKET) interrupt
• The Number of Busy Banks (NBUSYBK) interrupt
• The Received OUT isochronous Multiple Data Interrupt (MDATAI)
• The Received OUT isochronous DataX Interrupt (DATAXI)
The exception device endpoint interrupts are:
• The Underflow Interrupt (UNDERFI)
• The NAKed OUT Interrupt (NAKOUTI)
• The High-bandwidth isochronous IN error Interrupt (HBISOINERRI)
• The NAKed IN Interrupt (NAKINI)
• The High-bandwidth isochronous IN Flush error Interrupt (HBISOFLUSHI)
• The Overflow Interrupt (OVERFI)
• The STALLed Interrupt (STALLEDI)
• The CRC Error Interrupt (CRCERRI)
• The Transaction error (ERRORTRANS) interrupt
•DMA interrupts
The processing device DMA interrupts are:
• The End of USB Transfer Status (EOTSTA) interrupt
• The End of Channel Buffer Status (EOCHBUFFSTA) interrupt
• The Descriptor Loaded Status (DESCLDSTA) interrupt
There is no exception device DMA interrupt.
26.7.2.20
Test Modes
When written to one, the UDCON.TSTPCKT bit switches the USB device controller in a “test
packet”mode:
The transceiver repeatedly transmit the packet stored in the current bank. TSTPCKT must be
written to zero to exit the “test-packet” mode. The endpoint shall be reset by software after a
“test-packet” mode.
This enables the testing of rise and falling times, eye patterns, jitter, and any other dynamic
waveform specifications.
The flow control used to send the packets is as follows:
• TSTPCKT=1;
• Store data in an endpoint bank
• Write a zero to FifoCON bit
To stop the test-packet mode, just write a zero to the TSTPCKT bit.
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26.7.3
26.7.3.1
USB Host Operation
Description of pipes
For the USBB in host mode, the term “pipe” is used instead of “endpoint” (used in device mode).
A host pipe corresponds to a device endpoint, as described by the Figure 26-21 on page 657
from the USB specification.
Figure 26-21. USB Communication Flow
In host mode, the USBB associates a pipe to a device endpoint, considering the device configuration descriptors.
26.7.3.2
Power-On and reset
Figure 26-22 on page 657 describes the USBB host mode main states.
Figure 26-22. Host Mode States
Device
Disconnection
Macro off
Clock stopped
<any
other
state>
Idle
Device
Connection
Device
Disconnection
Ready
SOFE = 0
SOFE = 1
Suspend
After a hardware reset, the USBB host mode is in the Reset state.
When the USBB is enabled (USBE is one) in host mode (ID is zero), its host mode state goes to
the Idle state. In this state, the controller waits for device connection with minimal power con-
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sumption. The USB pad should be in the Idle state. Once a device is connected, the macro
enters the Ready state, what does not require the USB clock to be activated.
The controller enters the Suspend state when the USB bus is in a “Suspend” state, i.e., when
the host mode does not generate the “Start of Frame (SOF)”. In this state, the USB consumption
is minimal. The host mode exits the Suspend state when starting to generate the SOF over the
USB line.
26.7.3.3
Device detection
A device is detected by the USBB host mode when D+ or D- is no longer tied low, i.e., when the
device D+ or D- pull-up resistor is connected. To enable this detection, the host controller has to
provide the VBus power supply to the device by setting the VBUSRQ bit (by writing a one to the
VBUSRQS bit).
The device disconnection is detected by the host controller when both D+ and D- are pulled
down.
26.7.3.4
USB reset
The USBB sends a USB bus reset when the user write a one to the Send USB Reset bit in the
Host General Control register (UHCON.RESET). The USB Reset Sent Interrupt bit in the Host
Global Interrupt register (UHINT.RSTI) is set when the USB reset has been sent. In this case, all
the pipes are disabled and de-allocated.
If the bus was previously in a “Suspend” state (the Start of Frame Generation Enable (SOFE) bit
in UHCON is zero), the USBB automatically switches it to the “Resume” state, the Host WakeUp Interrupt (HWUPI) bit in UHINT is set and the SOFE bit is set in order to generate SOFs or
micro SOFs immediately after the USB reset.
At the end of the reset, the user should check the USBSTA.SPEED field to know the speed running according to the peripheral capability (LS.FS/HS)
26.7.3.5
Pipe reset
A pipe can be reset at any time by writing a one to the Pipe n Reset (PRSTn) bit in the UPRST
register. This is recommended before using a pipe upon hardware reset or when a USB bus
reset has been sent. This resets:
• The internal state machine of this pipe
• The receive and transmit bank FIFO counters
• All the registers of this pipe (UPCFGn, UPSTAn, UPCONn), except its configuration (ALLOC,
PBK, PSIZE, PTOKEN, PTYPE, PEPNUM, INTFRQ in UPCFGn) and its Data Toggle
Sequence field in the Pipe n Status register (UPSTAn.DTSEQ).
The pipe configuration remains active and the pipe is still enabled.
The pipe reset may be associated with a clear of the data toggle sequence. This can be
achieved by setting the Reset Data Toggle bit in the Pipe n Control register (UPCONn.RSTDT)
(by writing a one to the Reset Data Toggle Set bit in the Pipe n Control Set register
(UPCONnSET.RSTDTS)).
In the end, the user has to write a zero to the PRSTn bit to complete the reset operation and to
start using the FIFO.
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26.7.3.6
Pipe activation
The pipe is maintained inactive and reset (see Section 26.7.3.5 for more details) as long as it is
disabled (PENn is zero). The Data Toggle Sequence field (DTSEQ) is also reset.
The algorithm represented on Figure 26-23 on page 659 must be followed in order to activate a
pipe.
Figure 26-23. Pipe Activation Algorithm
Pipe
Activation
PENn = 1
Enable the pipe.
Configure the pipe:
- interrupt request frequency
- endpoint number
- type
- size
- number of banks
Allocate the configured DPRAM banks.
UPCFGn
INTFRQ
PEPNUM
PTYPE
PTOKEN
PSIZE
PBK
ALLOC
CFGOK ==
1?
Yes
Pipe Activated
Test if the pipe configuration is
correct.
No
ERROR
As long as the pipe is not correctly configured (UPSTAn.CFGOK is zero), the controller can not
send packets to the device through this pipe.
The UPSTAn.CFGOK bit is set only if the configured size and number of banks are correct compared to their maximal allowed values for the pipe (see Table 26-1 on page 630) and to the
maximal FIFO size (i.e. the DPRAM size).
See Section 26.7.1.6 for more details about DPRAM management.
Once the pipe is correctly configured (UPSTAn.CFGOK is zero), only the PTOKEN and INTFRQ
fields can be written by software. INTFRQ is meaningless for non-interrupt pipes.
When starting an enumeration, the user gets the device descriptor by sending a
GET_DESCRIPTOR USB request. This descriptor contains the maximal packet size of the
device default control endpoint (bMaxPacketSize0) and the user re-configures the size of the
default control pipe with this size parameter.
26.7.3.7
Address setup
Once the device has answered the first host requests with the default device address 0, the host
assigns a new address to the device. The host controller has to send an USB reset to the device
and to send a SET_ADDRESS(addr) SETUP request with the new address to be used by the
device. Once this SETUP transaction is over, the user writes the new address into the USB Host
Address for Pipe n field in the USB Host Device Address register (UHADDR.UHADDRPn). All
following requests, on all pipes, will be performed using this new address.
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When the host controller sends an USB reset, the UHADDRPn field is reset by hardware and the
following host requests will be performed using the default device address 0.
26.7.3.8
Remote wake-up
The controller host mode enters the Suspend state when the UHCON.SOFE bit is written to
zero. No more “Start of Frame” is sent on the USB bus and the USB device enters the Suspend
state 3ms later.
The device awakes the host by sending an Upstream Resume (Remote Wake-Up feature).
When the host controller detects a non-idle state on the USB bus, it set the Host Wake-Up interrupt (HWUPI) bit in UHINT. If the non-idle bus state corresponds to an Upstream Resume (K
state), the Upstream Resume Received Interrupt (RXRSMI) bit in UHINT is set. The user has to
generate a Downstream Resume within 1ms and for at least 20ms by writing a one to the Send
USB Resume (RESUME) bit in UHCON. It is mandatory to write a one to UHCON.SOFE before
writing a one to UHCON.RESUME to enter the Ready state, else UHCON.RESUME will have no
effect.
26.7.3.9
Management of control pipes
A control transaction is composed of three stages:
• SETUP
• Data (IN or OUT)
• Status (OUT or IN)
The user has to change the pipe token according to each stage.
For the control pipe, and only for it, each token is assigned a specific initial data toggle
sequence:
• SETUP: Data0
• IN: Data1
• OUT: Data1
26.7.3.10
Management of IN pipes
IN packets are sent by the USB device controller upon IN requests from the host. All the data
can be read which acknowledges or not the bank when it is empty.
The pipe must be configured first.
When the host requires data from the device, the user has to select beforehand the IN request
mode with the IN Request Mode bit in the Pipe n IN Request register (UPINRQn.INMODE):
• When INMODE is written to zero, the USBB will perform (INRQ + 1) IN requests before
freezing the pipe.
• When INMODE is written to one, the USBB will perform IN requests endlessly when the pipe
is not frozen by the user.
The generation of IN requests starts when the pipe is unfrozen (the Pipe Freeze (PFREEZE)
field in UPCONn is zero).
The Received IN Data Interrupt (RXINI) bit in UPSTAn is set at the same time as the FIFO Control (FIFOCON) bit in UPCONn when the current bank is full. This triggers a PnINT interrupt if the
Received IN Data Interrupt Enable (RXINE) bit in UPCONn is one.
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RXINI shall be cleared by software (by writing a one to the Received IN Data Interrupt Clear bit
in the Pipe n Control Clear register(UPCONnCLR.RXINIC)) to acknowledge the interrupt, what
has no effect on the pipe FIFO.
The user then reads from the FIFO and clears the FIFOCON bit (by writing a one to the FIFO
Control Clear (FIFOCONC) bit in UPCONnCLR) to free the bank. If the IN pipe is composed of
multiple banks, this also switches to the next bank. The RXINI and FIFOCON bits are updated in
accordance with the status of the next bank.
RXINI shall always be cleared before clearing FIFOCON.
The Read/Write Allowed (RWALL) bit in UPSTAn is set when the current bank is not empty, i.e.,
the software can read further data from the FIFO.
Figure 26-24. Example of an IN Pipe with 1 Data Bank
DATA
(bank 0)
IN
ACK
IN
DATA
(bank 0)
HW
ACK
HW
SW
RXINI
SW
read data from CPU
BANK 0
FIFOCON
read data from CPU
BANK 0
SW
Figure 26-25. Example of an IN Pipe with 2 Data Banks
IN
DATA
(bank 0)
ACK
IN
DATA
(bank 1)
HW
RXINI
FIFOCON
26.7.3.11
ACK
HW
SW
SW
read data from CPU
BANK 0
SW
read data from CPU
BANK 1
Management of OUT pipes
OUT packets are sent by the host. All the data can be written which acknowledges or not the
bank when it is full.
The pipe must be configured and unfrozen first.
The Transmitted OUT Data Interrupt (TXOUTI) bit in UPSTAn is set at the same time as FIFOCON when the current bank is free. This triggers a PnINT interrupt if the Transmitted OUT Data
Interrupt Enable (TXOUTE) bit in UPCONn is one.
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TXOUTI shall be cleared by software (by writing a one to the Transmitted OUT Data Interrupt
Clear (TXOUTIC) bit in UPCONnCLR) to acknowledge the interrupt, what has no effect on the
pipe FIFO.
The user then writes into the FIFO and clears the FIFOCON bit to allow the USBB to send the
data. If the OUT pipe is composed of multiple banks, this also switches to the next bank. The
TXOUTI and FIFOCON bits are updated in accordance with the status of the next bank.
TXOUTI shall always be cleared before clearing FIFOCON.
The UPSTAn.RWALL bit is set when the current bank is not full, i.e., the software can write further data into the FIFO.
Note that if the user decides to switch to the Suspend state (by writing a zero to the
UHCON.SOFE bit) while a bank is ready to be sent, the USBB automatically exits this state and
the bank is sent.
Note that in High-Speed operating mode, the host controller automatically manages the PING
protocol to maximize the USB bandwidth. The user can tune the PING protocol by handling the
Ping Enable (PINGEN) bit and the bInterval Parameter for the Bulk-Out/Ping Transaction
(BINTERVALL) field in UPCFGn. See the Section 26.8.3.12 for more details.
Figure 26-26. Example of an OUT Pipe with one Data Bank
DATA
(bank 0)
OUT
ACK
OUT
HW
TXOUTI
SW
SW
write data to CPU
BANK 0
FIFOCON
write data to CPU
BANK 0
SW
SW
Figure 26-27. Example of an OUT Pipe with two Data Banks and no Bank Switching Delay
OUT
DATA
(bank 0)
ACK
OUT
DATA
(bank 1)
ACK
HW
TXOUTI
FIFOCON
SW
SW
write data to CPU SW
BANK 0
SW
write data to CPU
BANK 1
SW
write data to CPU
BANK0
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Figure 26-28. Example of an OUT Pipe with two Data Banks and a Bank Switching Delay
DATA
(bank 0)
OUT
ACK
OUT
DATA
(bank 1)
ACK
HW
TXOUTI
SW
FIFOCON
26.7.3.12
SW
write data to CPU
BANK 0
SW
SW
write data to CPU
BANK 1
SW
write data to CPU
BANK0
CRC error
This error exists only for isochronous IN pipes. It set the CRC Error Interrupt (CRCERRI) bit,
what triggers a PnINT interrupt if then the CRC Error Interrupt Enable (CRCERRE) bit in
UPCONn is one.
A CRC error can occur during IN stage if the USBB detects a corrupted received packet. The IN
packet is stored in the bank as if no CRC error had occurred (RXINI is set).
26.7.3.13
Interrupts
See the structure of the USB host interrupt system on Figure 26-6 on page 638.
There are two kinds of host interrupts: processing, i.e. their generation is part of the normal processing, and exception, i.e. errors (not related to CPU exceptions).
•Global interrupts
The processing host global interrupts are:
• The Device Connection Interrupt (DCONNI)
• The Device Disconnection Interrupt (DDISCI)
• The USB Reset Sent Interrupt (RSTI)
• The Downstream Resume Sent Interrupt (RSMEDI)
• The Upstream Resume Received Interrupt (RXRSMI)
• The Host Start of Frame Interrupt (HSOFI)
• The Host Wake-Up Interrupt (HWUPI)
• The Pipe n Interrupt (PnINT)
• The DMA Channel n Interrupt (DMAnINT)
There is no exception host global interrupt.
•Pipe interrupts
The processing host pipe interrupts are:
• The Received IN Data Interrupt (RXINI)
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• The Transmitted OUT Data Interrupt (TXOUTI)
• The Transmitted SETUP Interrupt (TXSTPI)
• The Short Packet Interrupt (SHORTPACKETI)
• The Number of Busy Banks (NBUSYBK) interrupt
The exception host pipe interrupts are:
• The Underflow Interrupt (UNDERFI)
• The Pipe Error Interrupt (PERRI)
• The NAKed Interrupt (NAKEDI)
• The Overflow Interrupt (OVERFI)
• The Received STALLed Interrupt (RXSTALLDI)
• The CRC Error Interrupt (CRCERRI)
•DMA interrupts
The processing host DMA interrupts are:
• The End of USB Transfer Status (EOTSTA) interrupt
• The End of Channel Buffer Status (EOCHBUFFSTA) interrupt
• The Descriptor Loaded Status (DESCLDSTA) interrupt
There is no exception host DMA interrupt.
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26.7.4
26.7.4.1
USB DMA Operation
Introduction
USB packets of any length may be transferred when required by the USBB. These transfers
always feature sequential addressing. These two characteristics mean that in case of high
USBB throughput, both HSB ports will benefit from “incrementing burst of unspecified length”
since the average access latency of HSB slaves can then be reduced.
The DMA uses word “incrementing burst of unspecified length” of up to 256 beats for both data
transfers and channel descriptor loading. A burst may last on the HSB busses for the duration of
a whole USB packet transfer, unless otherwise broken by the HSB arbitration or the HSB 1kbyte
boundary crossing.
Packet data HSB bursts may be locked on a DMA buffer basis for drastic overall HSB bus bandwidth performance boost with paged memories. This is because these memories row (or bank)
changes, which are very clock-cycle consuming, will then likely not occur or occur once instead
of dozens of times during a single big USB packet DMA transfer in case other HSB masters
address the memory. This means up to 128 words single cycle unbroken HSB bursts for bulk
pipes/endpoints and 256 words single cycle unbroken bursts for isochronous pipes/endpoints.
This maximal burst length is then controlled by the lowest programmed USB pipe/endpoint size
(PSIZE/EPSIZE) and the Channel Byte Length (CHBYTELENGTH) field in the Device DMA
Channel n Control (UDDMAnCONTROL) register.
The USBB average throughput may be up to nearly 53 Mbyte/s. Its average access latency
decreases as burst length increases due to the zero wait-state side effect of unchanged
pipe/endpoint. Word access allows reducing the HSB bandwidth required for the USB by four
compared to native byte access. If at least 0 wait-state word burst capability is also provided by
the other DMA HSB bus slaves, each of both DMA HSB busses need less than 60% bandwidth
allocation for full USB bandwidth usage at 33MHz, and less than 30% at 66MHz.
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Figure 26-29. Example of DMA Chained List
Transfer Descriptor
USB DMA Channel X Registers
(Current Transfer Descriptor)
Next Descriptor Address
Next Descriptor Address
HSB Address
Transfer Descriptor
Control
Next Descriptor Address
HSB Address
HSB Address
Transfer Descriptor
Control
Next Descriptor Address
Control
HSB Address
Status
Control
NULL
Memory Area
Data Buffer 1
Data Buffer 2
Data Buffer 3
26.7.4.2
DMA Channel descriptor
The DMA channel transfer descriptor is loaded from the memory.
Be careful with the alignment of this buffer.
The structure of the DMA channel transfer descriptor is defined by three parameters as
described below:
• Offset 0:
– The address must be aligned: 0xXXXX0
– DMA Channel n Next Descriptor Address Register: DMAnNXTDESCADDR
• Offset 4:
– The address must be aligned: 0xXXXX4
– DMA Channel n HSB Address Register: DMAnADDR
• Offset 8:
– The address must be aligned: 0xXXXX8
– DMA Channel n Control Register: DMAnCONTROL
26.7.4.3
Programming a chanel:
Each DMA transfer is unidirectionnal. Direction depends on the type of the associated endpoint
(IN or OUT).
Three registers, the UDDMAnNEXTDESC, the UDDMAnADDR and UDDMAnCONTROL need
to be programmed to set up wether single or multiple transfer is used.
The following example refers to OUT endpoint. For IN endpoint, the programming is symmetric.
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•Single-block transfer programming example for OUT transfer :
The following sequence may be used:
• Configure the targerted endpoint (source) as OUT type, and set the automatic bank switching
for this endpoint in the UECFGn register to handle multiple OUT packet.
• Write the starting destination address in the UDDMAnADDR register.
• There is no need to program the UDDMAnNEXTDESC register.
• Program the channel byte length in the UDDMAnCONTROL register.
• Program the UDDMAnCONTROL according to Row 2 as shown in Figure 26-7 on page 720
to set up a single block transfer.
The UDDMAnSTATUS.CHEN bit is set indicating that the dma channel is enable.
As soon as an OUT packet is stored inside the endpoint, the UDDMAnSTATUS.CHACTIVE bit
is set to one, indicating that the DMA channel is transfering data from the endpoint to the destination address until the endpoint is empty or the channel byte length is reached. Once the
endpoint is empty, the UDDMAnSTATUS.CHACTIVE bit is cleared.
Once the DMA channel is completed (i.e : the channel byte length is reached), after one or multiple processed OUT packet, the UDDMAnCONTROL.CHEN bit is cleared. As a consequence,
the UDDMAnSTATUS.CHEN bit is also cleared, and the UDDMAnSTATUS.EOCHBUFFSTA bit
is set indicating a end of dma channel. If the UDDMAnCONTROL.DMAENDEN bit was set, the
last endpoint bank will be properly released even if there are some residual datas inside, i.e:
OUT packet truncation at the end of DMA buffer when the dma channel byte lenght is not an
integral multiple of the endpoint size.
•Programming example for single-block dma transfer with automatic closure for OUT transfer :
The idea is to automatically close the DMA transfer at the end of the OUT transaction (received
short packet). The following sequence may be used:
• Configure the targerted endpoint (source) as OUT type, and set the automatic bank switching
for this endpoint in the UECFGn register to handle multiple OUT packet.
• Write the starting destination address in the UDDMAnADDR register.
• There is no need to program the UDDMAnNEXTDESC register.
• Program the channel byte length in the UDDMAnCONTROL register.
• Set the BUFFCLOSEINEN bit in the UDDMAnCONTROL register.
• Program the UDDMAnCONTROL according to Row 2 as shown in Figure 26-7 on page 720
to set up a single block transfer.
As soon as an OUT packet is stored inside the endpoint, the UDDMAnSTATUS.CHACTIVE bit
is set to one, indicating that the DMA channel is transfering data from the endpoint to the destination address until the endpoint is empty. Once the endpoint is empty, the
UDDMAnSTATUS.CHACTIVE bit is cleared.
After one or multiple processed OUT packet, the DMA channel is completed after sourcing a
short packet. Then, the UDDMAnCONTROL.CHEN bit is cleared. As a consequence, after a few
cycles latency, the UDDMAnSTATUS.CHEN bit is also cleared, and the UDDMAnSTATUS.EOTSTA bit is set indicating that the DMA was closed by a end of USB transaction.
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•Programming example for multi-block dma transfer : run and link at end of buffer
The idea is to run first a single block transfer followed automatically by a linked list of DMA. The
following sequence may be used:
• Configure the targerted endpoint (source) as OUT type, and set the automatic bank switching
for this endpoint in the UECFGn register to handle multiple OUT packet.
• Set up the chain of linked list of descripor in memory. Each descriptor is composed of 3 items
: channel next descriptor address, channel destination address and channel control. The last
descriptor should be programmed according to row 2 as shown in Figure 26-7 on page 720.
• Write the starting destination address in the UDDMAnADDR register.
• Program the UDDMAnNEXTDESC register.
• Program the channel byte length in the UDDMAnCONTROL register.
• Optionnaly set the BUFFCLOSEINEN bit in the UDDMAnCONTROL register.
• Program the UDDMAnCONTROL according to Row 4 as shown in Figure 26-7 on page 720.
The UDDMAnSTATUS.CHEN bit is set indicating that the dma channel is enable.
As soon as an OUT packet is stored inside the endpoint, the UDDMAnSTATUS.CHACTIVE bit
is set to one, indicating that the DMA channel is transfering data from the endpoint to the destination address until the endpoint is empty or the channel byte length is reached. Once the
endpoint is empty, the UDDMAnSTATUS.CHACTIVE bit is cleared.
Once the first DMA channel is completed (i.e : the channel byte length is reached), after one or
multiple processed OUT packet, the UDDMAnCONTROL.CHEN bit is cleared. As a consequence, the UDDMAnSTATUS.CHEN bit is also cleared, and the
UDDMAnSTATUS.EOCHBUFFSTA bit is set indicating a end of dma channel. If the UDDMAnCONTROL.DMAENDEN bit was set, the last endpoint bank will be properly released even if
there are some residual datas inside, i.e: OUT packet truncation at the end of DMA buffer when
the dma channel byte lenght is not an integral multiple of the endpoint size. Note that the
UDDMAnCONTROL.LDNXTCH bit remains to one indicating that a linked descriptor will be
loaded.
Once the new descriptor is loaded from the UDDMAnNEXTDESC memory address, the UDDMAnSTATUS.DESCLDSTA bit is set, and the UDDMAnCONTROL register is updated from the
memory. As a consequence, the UDDMAnSTATUS.CHEN bit is set, and the UDDMAnSTATUS.CHACTIVE is set as soon as the endpoint is ready to be sourced by the DMA (received
OUT data packet).
This sequence is repeated until a last linked descriptor is processed. The last descriptor is
detected according to row 2 as shown in Figure 26-7 on page 720.
At the end of the last descriptor, the UDDMAnCONTROL.CHEN bit is cleared. As a consequence, after a few cycles latency, the UDDMAnSTATUS.CHEN bit is also cleared.
•Programming example for multi-block dma transfer : load next descriptor now
The idea is to directly run first a linked list of DMA. The following sequence may be used: The
following sequence may be used:
• Configure the targerted endpoint (source) as OUT type, and set the automatic bank switching
for this endpoint in the UECFGn register to handle multiple OUT packet.
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• Set up the chain of linked list of descripor in memory. Each descriptor is composed of 3 items
: channel next descriptor address, channel destination address and channel control. The last
descriptor should be programmed according to row 2 as shown in Figure 26-7 on page 720.
• Program the UDDMAnNEXTDESC register.
• Program the UDDMAnCONTROL according to Row 3 as shown in Figure 26-7 on page 720.
The UDDMAnSTATUS.CHEN bit is 0 and the UDDMAnSTATUS.LDNXTCHDESCEN is set indicating that the DMA channel is pending until the endpoint is ready (received OUT packet).
As soon as an OUT packet is stored inside the endpoint, the UDDMAnSTATUS.CHACTIVE bit
is set to one. Then after a few cycle latency, the new descriptor is loaded from the memory and
the UDDMAnSTATUS.DESCLDSTA is set.
At the end of this DMA (for instance when the channel byte length has reached 0), the
UDDMAnCONTROL.CHEN bit is cleared, and then the UDDMAnSTATUS.CHEN bit is also
cleared. If the UDDMAnCONTROL.LDNXTCH value is one, a new descriptor is loaded.
This sequence is repeated until a last linked descriptor is processed. The last descriptor is
detected according to row 2 as shown in Figure 26-7 on page 720.
At the end of the last descriptor, the UDDMAnCONTROL.CHEN bit is cleared. As a consequence, after a few cycles latency, the UDDMAnSTATUS.CHEN bit is also cleared.
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26.8
User Interface
Table 26-5.
USBB Register Memory Map
Offset
Register
Name
Access
Reset Value
0x0000
Device General Control Register
UDCON
Read/Write
0x00000100
0x0004
Device Global Interrupt Register
UDINT
Read-Only
0x00000000
0x0008
Device Global Interrupt Clear Register
UDINTCLR
Write-Only
0x00000000
0x000C
Device Global Interrupt Set Register
UDINTSET
Write-Only
0x00000000
0x0010
Device Global Interrupt Enable Register
UDINTE
Read-Only
0x00000000
0x0014
Device Global Interrupt Enable Clear Register
UDINTECLR
Write-Only
0x00000000
0x0018
Device Global Interrupt Enable Set Register
UDINTESET
Write-Only
0x00000000
0x001C
Endpoint Enable/Reset Register
UERST
Read/Write
0x00000000
0x0020
Device Frame Number Register
UDFNUM
Read-Only
0x00000000
0x0100
Endpoint 0 Configuration Register
UECFG0
Read/Write
0x00002000
0x0104
Endpoint 1 Configuration Register
UECFG1
Read/Write
0x00002000
0x0108
Endpoint 2 Configuration Register
UECFG2
Read/Write
0x00002000
0x010C
Endpoint 3 Configuration Register
UECFG3
Read/Write
0x00002000
0x0110
Endpoint 4 Configuration Register
UECFG4
Read/Write
0x00002000
0x0114
Endpoint 5 Configuration Register
UECFG5
Read/Write
0x00002000
0x0118
Endpoint 6 Configuration Register
UECFG6
Read/Write
0x00002000
0x011C
Endpoint 7Configuration Register
UECFG7
Read/Write
0x00002000
0x0130
Endpoint 0 Status Register
UESTA0
Read-Only
0x00000100
0x0134
Endpoint 1 Status Register
UESTA1
Read-Only
0x00000100
0x0138
Endpoint 2 Status Register
UESTA2
Read-Only
0x00000100
0x013C
Endpoint 3 Status Register
UESTA3
Read-Only
0x00000100
0x0140
Endpoint 4 Status Register
UESTA4
Read-Only
0x00000100
0x0144
Endpoint 5 Status Register
UESTA5
Read-Only
0x00000100
0x0148
Endpoint 6 Status Register
UESTA6
Read-Only
0x00000100
0x014C
Endpoint 7Status Register
UESTA7
Read-Only
0x00000100
0x0160
Endpoint 0 Status Clear Register
UESTA0CLR
Write-Only
0x00000000
0x0164
Endpoint 1 Status Clear Register
UESTA1CLR
Write-Only
0x00000000
0x0168
Endpoint 2 Status Clear Register
UESTA2CLR
Write-Only
0x00000000
0x016C
Endpoint 3 Status Clear Register
UESTA3CLR
Write-Only
0x00000000
0x0170
Endpoint 4 Status Clear Register
UESTA4CLR
Write-Only
0x00000000
0x0174
Endpoint 5 Status Clear Register
UESTA5CLR
Write-Only
0x00000000
0x0178
Endpoint 6 Status Clear Register
UESTA6CLR
Write-Only
0x00000000
0x017C
Endpoint 7 Status Clear Register
UESTA7CLR
Write-Only
0x00000000
0x0190
Endpoint 0 Status Set Register
UESTA0SET
Write-Only
0x00000000
0x0194
Endpoint 1 Status Set Register
UESTA1SET
Write-Only
0x00000000
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AT32UC3A3/A4
Table 26-5.
USBB Register Memory Map
Offset
Register
Name
Access
Reset Value
0x0198
Endpoint 2 Status Set Register
UESTA2SET
Write-Only
0x00000000
0x019C
Endpoint 3 Status Set Register
UESTA3SET
Write-Only
0x00000000
0x01A0
Endpoint 4 Status Set Register
UESTA4SET
Write-Only
0x00000000
0x01A4
Endpoint 5 Status Set Register
UESTA5SET
Write-Only
0x00000000
0x01A8
Endpoint 6 Status Set Register
UESTA6SET
Write-Only
0x00000000
0x01AC
Endpoint 7 Status Set Register
UESTA7SET
Write-Only
0x00000000
0x01C0
Endpoint 0 Control Register
UECON0
Read-Only
0x00000000
0x01C4
Endpoint 1 Control Register
UECON1
Read-Only
0x00000000
0x01C8
Endpoint 2 Control Register
UECON2
Read-Only
0x00000000
0x01CC
Endpoint 3 Control Register
UECON3
Read-Only
0x00000000
0x01D0
Endpoint 4 Control Register
UECON4
Read-Only
0x00000000
0x01D4
Endpoint 5 Control Register
UECON5
Read-Only
0x00000000
0x01D8
Endpoint 6 Control Register
UECON6
Read-Only
0x00000000
0x01DC
Endpoint 7 Control Register
UECON7
Read-Only
0x00000000
0x01F0
Endpoint 0 Control Set Register
UECON0SET
Write-Only
0x00000000
0x01F4
Endpoint 1 Control Set Register
UECON1SET
Write-Only
0x00000000
0x01F8
Endpoint 2 Control Set Register
UECON2SET
Write-Only
0x00000000
0x01FC
Endpoint 3 Control Set Register
UECON3SET
Write-Only
0x00000000
0x0200
Endpoint 4 Control Set Register
UECON4SET
Write-Only
0x00000000
0x0204
Endpoint 5 Control Set Register
UECON5SET
Write-Only
0x00000000
0x0208
Endpoint 6 Control Set Register
UECON6SET
Write-Only
0x00000000
0x020C
Endpoint 7 Control Set Register
UECON7SET
Write-Only
0x00000000
0x0220
Endpoint 0 Control Clear Register
UECON0CLR
Write-Only
0x00000000
0x0224
Endpoint 1 Control Clear Register
UECON1CLR
Write-Only
0x00000000
0x0228
Endpoint 2 Control Clear Register
UECON2CLR
Write-Only
0x00000000
0x022C
Endpoint 3 Control Clear Register
UECON3CLR
Write-Only
0x00000000
0x0230
Endpoint 4 Control Clear Register
UECON4CLR
Write-Only
0x00000000
0x0234
Endpoint 5 Control Clear Register
UECON5CLR
Write-Only
0x00000000
0x0238
Endpoint 6 Control Clear Register
UECON6CLR
Write-Only
0x00000000
0x023C
Endpoint 7 Control Clear Register
UECON7CLR
Write-Only
0x00000000
0x0310
Device DMA Channel 1 Next Descriptor
Address Register
UDDMA1
NEXTDESC
Read/Write
0x00000000
0x0314
Device DMA Channel 1 HSB Address Register
UDDMA1
ADDR
Read/Write
0x00000000
0x0318
Device DMA Channel 1 Control Register
UDDMA1
CONTROL
Read/Write
0x00000000
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Table 26-5.
USBB Register Memory Map
Offset
Register
Name
Access
Reset Value
0x031C
Device DMA Channel 1 Status Register
UDDMA1
STATUS
Read/Write
0x00000000
0x0320
Device DMA Channel 2 Next Descriptor
Address Register
UDDMA2
NEXTDESC
Read/Write
0x00000000
0x0324
Device DMA Channel 2 HSB Address Register
UDDMA2
ADDR
Read/Write
0x00000000
0x0328
Device DMA Channel 2 Control Register
UDDMA2
CONTROL
Read/Write
0x00000000
0x032C
Device DMA Channel 2 Status Register
UDDMA2
STATUS
Read/Write
0x00000000
0x0330
Device DMA Channel 3 Next Descriptor
Address Register
UDDMA3
NEXTDESC
Read/Write
0x00000000
0x0334
Device DMA Channel 3 HSB Address Register
UDDMA3
ADDR
Read/Write
0x00000000
0x0338
Device DMA Channel 3 Control Register
UDDMA3
CONTROL
Read/Write
0x00000000
0x033C
Device DMA Channel 3 Status Register
UDDMA3
STATUS
Read/Write
0x00000000
0x0340
Device DMA Channel 4 Next Descriptor
Address Register
UDDMA4
NEXTDESC
Read/Write
0x00000000
0x0344
Device DMA Channel 4 HSB Address Register
UDDMA4
ADDR
Read/Write
0x00000000
0x0348
Device DMA Channel 4 Control Register
UDDMA4
CONTROL
Read/Write
0x00000000
0x034C
Device DMA Channel 4 Status Register
UDDMA4
STATUS
Read/Write
0x00000000
0x0350
Device DMA Channel 5 Next Descriptor
Address Register
UDDMA5
NEXTDESC
Read/Write
0x00000000
0x0354
Device DMA Channel 5 HSB Address Register
UDDMA5
ADDR
Read/Write
0x00000000
0x0358
Device DMA Channel 5 Control Register
UDDMA5
CONTROL
Read/Write
0x00000000
0x035C
Device DMA Channel 5 Status Register
UDDMA5
STATUS
Read/Write
0x00000000
0x0360
Device DMA Channel 6 Next Descriptor
Address Register
UDDMA6
NEXTDESC
Read/Write
0x00000000
0x0364
Device DMA Channel 6 HSB Address Register
UDDMA6
ADDR
Read/Write
0x00000000
0x0368
Device DMA Channel 6 Control Register
UDDMA6
CONTROL
Read/Write
0x00000000
0x036C
Device DMA Channel 6 Status Register
UDDMA6
STATUS
Read/Write
0x00000000
0x0370
Device DMA Channel 7 Next Descriptor
Address Register
UDDMA7
NEXTDESC
Read/Write
0x00000000
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AT32UC3A3/A4
Table 26-5.
USBB Register Memory Map
Offset
Register
Name
Access
Reset Value
0x0374
Device DMA Channel 7 HSB Address Register
UDDMA7
ADDR
Read/Write
0x00000000
0x0378
Device DMA Channel 7 Control Register
UDDMA7
CONTROL
Read/Write
0x00000000
0x037C
Device DMA Channel 7Status Register
UDDMA7
STATUS
Read/Write
0x00000000
0x0400
Host General Control Register
UHCON
Read/Write
0x00000000
0x0404
Host Global Interrupt Register
UHINT
Read-Only
0x00000000
0x0408
Host Global Interrupt Clear Register
UHINTCLR
Write-Only
0x00000000
0x040C
Host Global Interrupt Set Register
UHINTSET
Write-Only
0x00000000
0x0410
Host Global Interrupt Enable Register
UHINTE
Read-Only
0x00000000
0x0414
Host Global Interrupt Enable Clear Register
UHINTECLR
Write-Only
0x00000000
0x0418
Host Global Interrupt Enable Set Register
UHINTESET
Write-Only
0x00000000
0x0041C
Pipe Enable/Reset Register
UPRST
Read/Write
0x00000000
0x0420
Host Frame Number Register
UHFNUM
Read/Write
0x00000000
0x0424
Host Address 1 Register
UHADDR1
Read/Write
0x00000000
0x0428
Host Address 2 Register
UHADDR2
Read/Write
0x00000000
0x0500
Pipe 0 Configuration Register
UPCFG0
Read/Write
0x00000000
0x0504
Pipe 1 Configuration Register
UPCFG1
Read/Write
0x00000000
0x0508
Pipe 2 Configuration Register
UPCFG2
Read/Write
0x00000000
0x050C
Pipe 3 Configuration Register
UPCFG3
Read/Write
0x00000000
0x0510
Pipe 4 Configuration Register
UPCFG4
Read/Write
0x00000000
0x0514
Pipe 5 Configuration Register
UPCFG5
Read/Write
0x00000000
0x0518
Pipe 6 Configuration Register
UPCFG6
Read/Write
0x00000000
0x051C
Pipe 7 Configuration Register
UPCFG7
Read/Write
0x00000000
0x0530
Pipe 0 Status Register
UPSTA0
Read-Only
0x00000000
0x0534
Pipe 1 Status Register
UPSTA1
Read-Only
0x00000000
0x0538
Pipe 2 Status Register
UPSTA2
Read-Only
0x00000000
0x053C
Pipe 3 Status Register
UPSTA3
Read-Only
0x00000000
0x0540
Pipe 4 Status Register
UPSTA4
Read-Only
0x00000000
0x0544
Pipe 5 Status Register
UPSTA5
Read-Only
0x00000000
0x0548
Pipe 6 Status Register
UPSTA6
Read-Only
0x00000000
0x054C
Pipe 7Status Register
UPSTA7
Read-Only
0x00000000
0x0560
Pipe 0 Status Clear Register
UPSTA0CLR
Write-Only
0x00000000
0x0564
Pipe 1 Status Clear Register
UPSTA1CLR
Write-Only
0x00000000
0x0568
Pipe 2 Status Clear Register
UPSTA2CLR
Write-Only
0x00000000
0x056C
Pipe 3 Status Clear Register
UPSTA3CLR
Write-Only
0x00000000
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AT32UC3A3/A4
Table 26-5.
USBB Register Memory Map
Offset
Register
Name
Access
Reset Value
0x0570
Pipe 4 Status Clear Register
UPSTA4CLR
Write-Only
0x00000000
0x0574
Pipe 5 Status Clear Register
UPSTA5CLR
Write-Only
0x00000000
0x0578
Pipe 6 Status Clear Register
UPSTA6CLR
Write-Only
0x00000000
0x057C
Pipe 7 Status Clear Register
UPSTA7CLR
Write-Only
0x00000000
0x0590
Pipe 0 Status Set Register
UPSTA0SET
Write-Only
0x00000000
0x0594
Pipe 1 Status Set Register
UPSTA1SET
Write-Only
0x00000000
0x0598
Pipe 2 Status Set Register
UPSTA2SET
Write-Only
0x00000000
0x059C
Pipe 3 Status Set Register
UPSTA3SET
Write-Only
0x00000000
0x05A0
Pipe 4 Status Set Register
UPSTA4SET
Write-Only
0x00000000
0x05A4
Pipe 5 Status Set Register
UPSTA5SET
Write-Only
0x00000000
0x05A8
Pipe 6 Status Set Register
UPSTA6SET
Write-Only
0x00000000
0x05AC
Pipe 7 Status Set Register
UPSTA7SET
Write-Only
0x00000000
0x05C0
Pipe 0 Control Register
UPCON0
Read-Only
0x00000000
0x05C4
Pipe 1 Control Register
UPCON1
Read-Only
0x00000000
0x05C8
Pipe 2 Control Register
UPCON2
Read-Only
0x00000000
0x05CC
Pipe 3 Control Register
UPCON3
Read-Only
0x00000000
0x05D0
Pipe 4 Control Register
UPCON4
Read-Only
0x00000000
0x05D4
Pipe 5 Control Register
UPCON5
Read-Only
0x00000000
0x05D8
Pipe 6 Control Register
UPCON6
Read-Only
0x00000000
0x05DC
Pipe 7 Control Register
UPCON7
Read-Only
0x00000000
0x05F0
Pipe 0 Control Set Register
UPCON0SET
Write-Only
0x00000000
0x05F4
Pipe 1 Control Set Register
UPCON1SET
Write-Only
0x00000000
0x05F8
Pipe 2 Control Set Register
UPCON2SET
Write-Only
0x00000000
0x05FC
Pipe 3 Control Set Register
UPCON3SET
Write-Only
0x00000000
0x0600
Pipe 4 Control Set Register
UPCON4SET
Write-Only
0x00000000
0x0604
Pipe 5 Control Set Register
UPCON5SET
Write-Only
0x00000000
0x0608
Pipe 6 Control Set Register
UPCON6SET
Write-Only
0x00000000
0x060C
Pipe 7 Control Set Register
UPCON7SET
Write-Only
0x00000000
0x0620
Pipe 0 Control Clear Register
UPCON0CLR
Write-Only
0x00000000
0x0624
Pipe 1 Control Clear Register
UPCON1CLR
Write-Only
0x00000000
0x0628
Pipe 2 Control Clear Register
UPCON2CLR
Write-Only
0x00000000
0x062C
Pipe 3 Control Clear Register
UPCON3CLR
Write-Only
0x00000000
0x0630
Pipe 4 Control Clear Register
UPCON4CLR
Write-Only
0x00000000
0x0634
Pipe 5 Control Clear Register
UPCON5CLR
Write-Only
0x00000000
0x0638
Pipe 6 Control Clear Register
UPCON6CLR
Write-Only
0x00000000
0x063C
Pipe 7 Control Clear Register
UPCON7CLR
Write-Only
0x00000000
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AT32UC3A3/A4
Table 26-5.
USBB Register Memory Map
Offset
Register
Name
Access
Reset Value
0x0650
Pipe 0 IN Request Register
UPINRQ0
Read/Write
0x00000000
0x0654
Pipe 1 IN Request Register
UPINRQ1
Read/Write
0x00000000
0x0658
Pipe 2 IN Request Register
UPINRQ2
Read/Write
0x00000000
0x065C
Pipe 3 IN Request Register
UPINRQ3
Read/Write
0x00000000
0x0660
Pipe 4 IN Request Register
UPINRQ4
Read/Write
0x00000000
0x0664
Pipe 5 IN Request Register
UPINRQ5
Read/Write
0x00000000
0x0668
Pipe 6 IN Request Register
UPINRQ6
Read/Write
0x00000000
0x066C
Pipe 7 IN Request Register
UPINRQ7
Read/Write
0x00000000
0x0680
Pipe 0 Error Register
UPERR0
Read/Write
0x00000000
0x0684
Pipe 1 Error Register
UPERR1
Read/Write
0x00000000
0x0688
Pipe 2 Error Register
UPERR2
Read/Write
0x00000000
0x068C
Pipe 3 Error Register
UPERR3
Read/Write
0x00000000
0x0690
Pipe 4 Error Register
UPERR4
Read/Write
0x00000000
0x0694
Pipe 5 Error Register
UPERR5
Read/Write
0x00000000
0x0698
Pipe 6 Error Register
UPERR6
Read/Write
0x00000000
0x069C
Pipe 7 Error Register
UPERR7
Read/Write
0x00000000
0x0710
Host DMA Channel 1 Next Descriptor Address
Register
UHDMA1
NEXTDESC
Read/Write
0x00000000
0x0714
Host DMA Channel 1 HSB Address Register
UHDMA1
ADDR
Read/Write
0x00000000
0x0718
Host DMA Channel 1 Control Register
UHDMA1
CONTROL
Read/Write
0x00000000
0x071C
Host DMA Channel 1 Status Register
UHDMA1
STATUS
Read/Write
0x00000000
0x0720
Host DMA Channel 2 Next Descriptor Address
Register
UHDMA2
NEXTDESC
Read/Write
0x00000000
0x0724
Host DMA Channel 2 HSB Address Register
UHDMA2
ADDR
Read/Write
0x00000000
0x0728
Host DMA Channel 2 Control Register
UHDMA2
CONTROL
Read/Write
0x00000000
0x072C
Host DMA Channel 2 Status Register
UHDMA2
STATUS
Read/Write
0x00000000
0x0730
Host DMA Channel 3 Next Descriptor Address
Register
UHDMA3
NEXTDESC
Read/Write
0x00000000
0x0734
Host DMA Channel 3 HSB Address Register
UHDMA3
ADDR
Read/Write
0x00000000
0x0738
Host DMA Channel 3 Control Register
UHDMA3
CONTROL
Read/Write
0x00000000
0x073C
Host DMA Channel 3Status Register
UHDMA3
STATUS
Read/Write
0x00000000
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AT32UC3A3/A4
Table 26-5.
USBB Register Memory Map
Offset
Register
Name
Access
Reset Value
0x0740
Host DMA Channel 4 Next Descriptor Address
Register
UHDMA4
NEXTDESC
Read/Write
0x00000000
0x0744
Host DMA Channel 4 HSB Address Register
UHDMA4
ADDR
Read/Write
0x00000000
0x0748
Host DMA Channel 4 Control Register
UHDMA4
CONTROL
Read/Write
0x00000000
0x074C
Host DMA Channel 4 Status Register
UHDMA4
STATUS
Read/Write
0x00000000
0x0750
Host DMA Channel 5 Next Descriptor Address
Register
UHDMA5
NEXTDESC
Read/Write
0x00000000
0x0754
Host DMA Channel 5 HSB Address Register
UHDMA5
ADDR
Read/Write
0x00000000
0x0758
Host DMA Channel 5 Control Register
UHDMA5
CONTROL
Read/Write
0x00000000
0x075C
Host DMA Channel 5 Status Register
UHDMA5
STATUS
Read/Write
0x00000000
0x0760
Host DMA Channel 6 Next Descriptor Address
Register
UHDMA6
NEXTDESC
Read/Write
0x00000000
0x0764
Host DMA Channel 6 HSB Address Register
UHDMA6
ADDR
Read/Write
0x00000000
0x0768
Host DMA Channel 6 Control Register
UHDMA6
CONTROL
Read/Write
0x00000000
0x076C
Host DMA Channel 6 Status Register
UHDMA6
STATUS
Read/Write
0x00000000
0x0770
Host DMA Channel 7 Next Descriptor Address
Register
UHDMA7
NEXTDESC
Read/Write
0x00000000
0x0774
Host DMA Channel 7 HSB Address Register
UHDMA7
ADDR
Read/Write
0x00000000
0x0778
Host DMA Channel 7 Control Register
UHDMA7
CONTROL
Read/Write
0x00000000
0x077C
Host DMA Channel 7 Status Register
UHDMA7
STATUS
Read/Write
0x00000000
0x0800
General Control Register
USBCON
Read/Write
0x03004000
0x0804
General Status Register
USBSTA
Read-Only
0x00000400
0x0808
General Status Clear Register
USBSTACLR
Write-Only
0x00000000
0x080C
General Status Set Register
USBSTASET
Write-Only
0x00000000
0x0818
IP Version Register
UVERS
Read-Only
-(1)
0x081C
IP Features Register
UFEATURES
Read-Only
-(1)
0x0820
IP PB Address Size Register
UADDRSIZE
Read-Only
-(1)
0x0824
IP Name Register 1
UNAME1
Read-Only
-(1)
0x0828
IP Name Register 2
UNAME2
Read-Only
-(1)
0x082C
USB Finite State Machine Status Register
USBFSM
Read-Only
0x00000009
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AT32UC3A3/A4
Table 26-6.
USB HSB Memory Map
Offset
Note:
Register
Name
Access
Reset Value
0x00000 0x0FFFC
Pipe/Endpoint 0 FIFO Data Register
USB
FIFO0DATA
Read/Write
Undefined
0x10000 0x1FFFC
Pipe/Endpoint 1 FIFO Data Register
USB
FIFO1DATA
Read/Write
Undefined
0x20000 0x2FFFC
Pipe/Endpoint 2 FIFO Data Register
USB
FIFO2DATA
Read/Write
Undefined
0x30000 0x3FFFC
Pipe/Endpoint 3 FIFO Data Register
USB
FIFO3DATA
Read/Write
Undefined
0x40000 0x4FFFC
Pipe/Endpoint 4 FIFO Data Register
USB
FIFO4DATA
Read/Write
Undefined
0x50000 0x5FFFC
Pipe/Endpoint 5 FIFO Data Register
USB
FIFO5DATA
Read/Write
Undefined
0x60000 0x6FFFC
Pipe/Endpoint 6 FIFO Data Register
USB
FIFO6DATA
Read/Write
Undefined
0x70000 0x7FFFC
Pipe/Endpoint 7 FIFO Data Register
USB
FIFO7DATA
Read/Write
Undefined
1. The reset values are device specific. Please refer to the Module Configuration section at the end of this chapter.
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26.8.1
USB General Registers
26.8.1.1
Name:
General Control Register
USBCON
Access Type:
Read/Write
Offset:
0x0800
Reset Value:
0x03004000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
UIMOD
UIDE
23
22
21
20
19
18
17
16
-
UNLOCK
-
-
15
14
13
12
11
10
9
8
USBE
FRZCLK
VBUSPO
OTGPADE
HNPREQ
SRPREQ
SRPSEL
VBUSHWC
7
6
5
4
3
2
1
0
STOE
HNPERRE
ROLEEXE
BCERRE
VBERRE
SRPE
VBUSTE
IDTE
TIMPAGE
TIMVALUE
• UIMOD: USBB Mode
This bit has no effect when UIDE is one (USB_ID input pin activated).
0: The module is in USB host mode.
1: The module is in USB device mode.
This bit can be written even if USBE is zero or FRZCLK is one. Disabling the USBB (by writing a zero to the USBE bit) does not
reset this bit.
• UIDE: USB_ID Pin Enable
0: The USB mode (device/host) is selected from the UIMOD bit.
1: The USB mode (device/host) is selected from the USB_ID input pin.
This bit can be written even if USBE is zero or FRZCLK is one. Disabling the USBB (by writing a zero to the USBE bit) does not
reset this bit.
• UNLOCK: Timer Access Unlock
1: The TIMPAGE and TIMVALUE fields are unlocked.
0: The TIMPAGE and TIMVALUE fields are locked.
The TIMPAGE and TIMVALUE fields can always be read, whatever the value of UNLOCK.
• TIMPAGE: Timer Page
This field contains the page value to access a special timer register.
• TIMVALUE: Timer Value
This field selects the timer value that is written to the special time register selected by TIMPAGE. See Section 26.7.1.8 for
details.
• USBE: USBB Enable
Writing a zero to this bit will reset the USBB, disable the USB transceiver and, disable the USBB clock inputs. Unless explicitly
stated, all registers then will become read-only and will be reset.
1: The USBB is enabled.
0: The USBB is disabled.
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This bit can be written even if FRZCLK is one.
• FRZCLK: Freeze USB Clock
1: The clock input are disabled (the resume detection is still active).This reduces power consumption. Unless explicitly stated, all
registers then become read-only.
0: The clock inputs are enabled.
This bit can be written even if USBE is zero. Disabling the USBB (by writing a zero to the USBE bit) does not reset this bit, but
this freezes the clock inputs whatever its value.
• VBUSPO: VBus Polarity
1: The USB_VBOF output signal is inverted (active low).
0: The USB_VBOF output signal is in its default mode (active high).
To be generic. May be useful to control an external VBus power module.
This bit can be written even if USBE is zero or FRZCLK is one. Disabling the USBB (by writing a zero to the USBE bit) does not
reset this bit.
• OTGPADE: OTG Pad Enable
1: The OTG pad is enabled.
0: The OTG pad is disabled.
This bit can be written even if USBE is zero or FRZCLK is one. Disabling the USBB (by writing a zero to the USBE bit) does not
reset this bit.
• HNPREQ: HNP Request
When the controller is in device mode:
Writing a one to this bit will initiate a HNP (Host Negociation Protocol).
Writing a zero to this bit has no effect.
This bit is cleared when the controller has initiated an HNP.
•
•
•
•
•
•
•
•
When the controller is in host mode:
Writing a one to this bit will accept a HNP.
Writing a zero to this bit will reject a HNP.
SRPREQ: SRP Request
Writing a one to this bit will initiate an SRP when the controller is in device mode.
Writing a zero to this bit has no effect.
This bit is cleared when the controller has initiated an SRP.
SRPSEL: SRP Selection
1: VBus pulsing is selected as SRP method.
0: Data line pulsing is selected as SRP method.
VBUSHWC: VBus Hardware Control
1: The hardware control over the USB_VBOF output pin is disabled.
0: The hardware control over the USB_VBOF output pin is enabled. The USBB resets the USB_VBOF output pin when a VBUS
problem occurs.
STOE: Suspend Time-Out Interrupt Enable
1: The Suspend Time-Out Interrupt (STOI) is enabled.
0: The Suspend Time-Out Interrupt (STOI) is disabled.
HNPERRE: HNP Error Interrupt Enable
1: The HNP Error Interrupt (HNPERRI) is enabled.
0: The HNP Error Interrupt (HNPERRI) is disabled.
ROLEEXE: Role Exchange Interrupt Enable
1: The Role Exchange Interrupt (ROLEEXI) is enabled.
0: The Role Exchange Interrupt (ROLEEXI) is disabled.
BCERRE: B-Connection Error Interrupt Enable
1: The B-Connection Error Interrupt (BCERRI) is enabled.
0: The B-Connection Error Interrupt (BCERRI) is disabled.
VBERRE: VBus Error Interrupt Enable
1: The VBus Error Interrupt (VBERRI) is enabled.
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0: The VBus Error Interrupt (VBERRI) is disabled.
• SRPE: SRP Interrupt Enable
1: The SRP Interrupt (SRPI) is enabled.
0: The SRP Interrupt (SRPI) is disabled.
• VBUSTE: VBus Transition Interrupt Enable
1: The VBus Transition Interrupt (VBUSTI) is enabled.
0: The VBus Transition Interrupt (VBUSTI) is disabled.
• IDTE: ID Transition Interrupt Enable
1: The ID Transition interrupt (IDTI) is enabled.
0: The ID Transition interrupt (IDTI) is disabled.
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26.8.1.2
General Status Register
Register Name:
USBSTA
Access Type:
Read-Only
Offset:
0x0804
Reset Value:
0x00000400
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
CLKUSABLE
VBUS
ID
VBUSRQ
-
7
6
5
4
3
2
1
0
STOI
HNPERRI
ROLEEXI
BCERRI
VBERRI
SRPI
VBUSTI
IDTI
SPEED
• CLKUSABLE: UTMI Clock Usable
This bit is set when the UTMI 30MHz is usable.
This bit is cleared when the UTMI 30MHz is not usable.
• SPEED: Speed Status
This field is set according to the controller speed mode. This field shall only be used in device mode.
SPEED
Speed Status
0
0
Full-Speed mode
1
0
Low-Speed mode
0
1
High-Speed mode
1
1
Reserved
• VBUS: VBus Level
This bit is set when the VBus line level is high, even if USBE is zero.
This bit is cleared when the VBus line level is low, even if USBE is zero.
This bit can be used in device mode to monitor the USB bus connection state of the application.
• ID: USB_ID Pin State
This bit is cleared when the USB_ID level is low, even if USBE is zero.
This bit is set when the USB_ID level is high, event if USBE is zero.
• VBUSRQ: VBus Request
This bit is set when the USBSTASET.VBUSRQS bit is written to one.
This bit is cleared when the USBSTACLR.VBUSRQC bit is written to one or when a VBus error occurs and VBUSHWC is zero.
1: The USB_VBOF output pin is driven high to enable the VBUS power supply generation.
0: The USB_VBOF output pin is driven low to disable the VBUS power supply generation.
This bit shall only be used in host mode.
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• STOI: Suspend Time-Out Interrupt
This bit is set when a time-out error (more than 200ms) has been detected after a suspend. This triggers a USB interrupt if
STOE is one.
This bit is cleared when the UBSTACLR.STOIC bit is written to one.
This bit shall only be used in host mode.
• HNPERRI: HNP Error Interrupt
This bit is set when an error has been detected during a HNP negotiation. This triggers a USB interrupt if HNPERRE is one.
This bit is cleared when the UBSTACLR.HNPERRIC bit is written to one.
This bit shall only be used in device mode.
• ROLEEXI: Role Exchange Interrupt
This bit is set when the USBB has successfully switched its mode because of an HNP negotiation (host to device or device to
host). This triggers a USB interrupt if ROLEEXE is one.
This bit is cleared when the UBSTACLR.ROLEEXIC bit is written to one.
• BCERRI: B-Connection Error Interrupt
This bit is set when an error occurs during the B-connection. This triggers a USB interrupt if BCERRE is one.
This bit is cleared when the UBSTACLR.BCERRIC bit is written to one.
This bit shall only be used in host mode.
• VBERRI: VBus Error Interrupt
This bit is set when a VBus drop has been detected. This triggers a USB interrupt if VBERRE is one.
This bit is cleared when the UBSTACLR.VBERRIC bit is written to one.
This bit shall only be used in host mode.
If a VBus problem occurs, then the VBERRI interrupt is generated even if the USBB does not go to an error state because of
VBUSHWC is one.
• SRPI: SRP Interrupt
This bit is set when an SRP has been detected. This triggers a USB interrupt if SRPE is one.
This bit is cleared when the UBSTACLR.SRPIC bit is written to one.
This bit shall only be used in host mode.
• VBUSTI: VBus Transition Interrupt
This bit is set when a transition (high to low, low to high) has been detected on the USB_VBUS pad. This triggers an USB
interrupt if VBUSTE is one.
This bit is cleared when the UBSTACLR.VBUSTIC bit is written to one.
This interrupt is generated even if the clock is frozen by the FRZCLK bit.
• IDTI: ID Transition Interrupt
This bit is set when a transition (high to low, low to high) has been detected on the USB_ID input pin. This triggers an USB
interrupt if IDTE is one.
This bit is cleared when the UBSTACLR.IDTIC bit is written to one.
This interrupt is generated even if the clock is frozen by the FRZCLK bit.
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26.8.1.3
General Status Clear Register
Register Name:
USBSTACLR
Access Type:
Write-Only
Offset:
0x0808
Read Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
VBUSRQC
-
7
6
5
4
3
2
1
0
STOIC
HNPERRIC
ROLEEXIC
BCERRIC
VBERRIC
SRPIC
VBUSTIC
IDTIC
Writing a one to a bit in this register will clear the corresponding bit in UBSTA.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
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26.8.1.4
General Status Set Register
Register Name:
USBSTASET
Access Type:
Write-Only
Offset:
0x080C
Read Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
VBUSRQS
-
7
6
5
4
3
2
1
0
STOIS
HNPERRIS
ROLEEXIS
BCERRIS
VBERRIS
SRPIS
VBUSTIS
IDTIS
Writing a one to a bit in this register will set the corresponding bit in UBSTA, what may be useful for test or debug purposes.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
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26.8.1.5
Version Register
Register Name:
UVERS
Access Type:
Read-Only
Offset:
0x0818
Read Value:
-
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
15
14
13
12
9
8
-
-
-
-
7
6
5
4
VARIANT
11
10
VERSION[11:8]
3
2
1
0
VERSION[7:0]
• VARIANT: Variant Number
Reserved. No functionality associated.
• VERSION: Version Number
Version number of the module. No functionality associated.
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26.8.1.6
Features Register
Register Name:
UFEATURES
Access Type:
Read-Only
Offset:
0x081C
Read Value:
-
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
ENHBISO7
ENHBISO6
ENHBISO5
ENHBISO4
ENHBISO3
ENHBISO2
ENHBISO1
DATABUS
15
14
13
12
11
10
9
8
BYTEWRITE
DPRAM
FIFOMAXSIZE
7
6
DMABUFFE
RSIZE
5
DMAFIFOWORDDEPTH
4
DMACHANNELNBR
3
2
1
0
EPTNBRMAX
• ENHBISOn: High Bandwidth Isochronous Feature for Endpoint n
1: The high bandwidth isochronous is supported.
1: The high bandwidth isochronous is not supported.
• DATABUS: Data Bus 16-8
1: The UTMI data bus is a 16-bit data path at 30MHz.
0: The UTMI data bus is a 8-bit data path at 60MHz.
• BYTEWRITEDPRAM: DPRAM Byte-Write Capability
1: The DPRAM is natively byte-write capable.
0: The DPRAM byte write lanes have shadow logic implemented in the USBB IP interface.
• FIFOMAXSIZE: Maximal FIFO Size
This field indicates the maximal FIFO size, i.e., the DPRAM size:
FIFOMAXSIZE
Maximal FIFO Size
0
0
0
< 256 bytes
0
0
1
< 512 bytes
0
1
0
< 1024 bytes
0
1
1
< 2048 bytes
1
0
0
< 4096 bytes
1
0
1
< 8192 bytes
1
1
0
< 16384 bytes
1
1
1
>= 16384 bytes
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• DMAFIFOWORDDEPTH: DMA FIFO Depth in Words
This field indicates the DMA FIFO depth controller in words:
DMAFIFOWORDDEPTH
DMA FIFO Depth in Words
0
0
0
0
16
0
0
0
1
1
0
0
1
0
2
...
1
1
1
1
15
• DMABUFFERSIZE: DMA Buffer Size
1: The DMA buffer size is 24bits.
0: The DMA buffer size is 16bits.
• DMACHANNELNBR: Number of DMA Channels
This field indicates the number of hardware-implemented DMA channels:
DMACHANNELNBR
Number of DMA Channels
0
0
0
Reserved
0
0
1
1
0
1
0
2
...
1
1
1
7
• EPTNBRMAX: Maximal Number of Pipes/Endpoints
This field indicates the number of hardware-implemented pipes/endpoints:
EPTNBRMAX
Maximal Number of Pipes/Endpoints
0
0
0
0
16
0
0
0
1
1
0
0
1
0
2
...
1
1
1
1
15
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26.8.1.7
Address Size Register
Register Name:
UADDRSIZE
Access Type:
Read-Only
Offset:
0x0820
Read Value:
-
31
30
29
28
27
26
25
24
18
17
16
10
9
8
2
1
0
UADDRSIZE[31:24]
23
22
21
20
19
UADDRSIZE[23:16]
15
14
13
12
11
UADDRSIZE[15:8]
7
6
5
4
3
UADDRSIZE[7:0]
• UADDRSIZE: IP PB Address Size
This field indicates the size of the PB address space reserved for the USBB IP interface.
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26.8.1.8
Name Register 1
Register Name:
UNAME1
Access Type:
Read-Only
Offset:
0x0824
Read Value:
-
31
30
29
28
27
26
25
24
18
17
16
10
9
8
2
1
0
UNAME1[31:24]
23
22
21
20
19
UNAME1[23:16]
15
14
13
12
11
UNAME1[15:8]
7
6
5
4
3
UNAME1[7:0]
• UNAME1: IP Name Part One
This field indicates the first part of the ASCII-encoded name of the USBB IP.
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26.8.1.9
Name Register 2
Register Name:
UNAME2
Access Type:
Read-Only
Offset:
0x0828
Read Value:
31
30
29
28
27
26
25
24
18
17
16
10
9
8
2
1
0
UNAME2[31:24]
23
22
21
20
19
UNAME2[23:16]
15
14
13
12
11
UNAME2[15:8]
7
6
5
4
3
UNAME2[7:0]
• UNAME2: IP Name Part Two
This field indicates the second part of the ASCII-encoded name of the USBB IP.
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26.8.1.10
Finite State Machine Status Register
Register Name:
USBFSM
Access Type:
Read-Only
Offset:
0x082C
Read Value:
0x00000009
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
DRDSTATE
• DRDSTATE
This field indicates the state of the USBB.
Refer to the OTG specification for more details.
DRDSTATE
Description
0
a_idle state: this is the start state for A-devices (when the ID pin is 0)
1
a_wait_vrise: In this state, the A-device waits for the voltage on VBus to rise above the Adevice VBus Valid threshold (4.4 V).
2
a_wait_bcon: In this state, the A-device waits for the B-device to signal a connection.
3
a_host: In this state, the A-device that operates in Host mode is operational.
4
a_suspend: The A-device operating as a host is in the suspend mode.
5
a_peripheral: The A-device operates as a peripheral.
6
a_wait_vfall: In this state, the A-device waits for the voltage on VBus to drop below the Adevice Session Valid threshold (1.4 V).
7
a_vbus_err: In this state, the A-device waits for recovery of the over-current condition that
caused it to enter this state.
8
a_wait_discharge: In this state, the A-device waits for the data usb line to discharge (100 us).
9
b_idle: this is the start state for B-device (when the ID pin is 1).
10
b_peripheral: In this state, the B-device acts as the peripheral.
11
b_wait_begin_hnp: In this state, the B-device is in suspend mode and waits until 3 ms before
initiating the HNP protocol if requested.
12
b_wait_discharge: In this state, the B-device waits for the data usb line to discharge (100 us)
before becoming Host.
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DRDSTATE
Description
13
b_wait_acon: In this state, the B-device waits for the A-device to signal a connect before
becoming B-Host.
14
b_host: In this state, the B-device acts as the Host.
15
b_srp_init: In this state, the B-device attempts to start a session using the SRP protocol.
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26.8.2
USB Device Registers
26.8.2.1
Device General Control Register
Register Name:
UDCON
Access Type:
Read/Write
Offset:
0x0000
Reset Value:
0x00000100
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
OPMODE2
15
14
13
12
11
10
9
8
TSTPCKT
TSTK
TSTJ
LS
RMWKUP
DETACH
7
6
5
4
1
0
ADDEN
SPDCONF
3
2
UADD
• OPMODE2: Specific Operational mode
1: The UTMI transceiver is in the «disable bit stuffing and NRZI encoding» operational mode for test purpose.
0: The UTMI transceiver is in normal operation mode.
• TSTPCKT: Test packet mode
1: The UTMI transceiver generates test packets for test purpose.
0: The UTMI transceiver is in normal operation mode.
• TSTK: Test mode K
1: The UTMI transceiver generates high-speed K state for test purpose.
0: The UTMI transceiver is in normal operation mode.
• TSTJ: Test mode J
1: The UTMI transceiver generates high-speed J state for test purpose.
0: The UTMI transceiver is in normal operation mode.
• LS: Low-Speed Mode Force
1: The low-speed mode is active.
0: The full-speed mode is active.
This bit can be written even if USBE is zero or FRZCLK is one. Disabling the USBB (by writing a zero to the USBE bit) does not
reset this bit.
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• SPDCONF: Speed Configuration
This field contains the peripheral speed.
SPDCONF
Speed
0
0
Normal mode: the peripheral starts in full-speed mode and performs a high-speed reset to
switch to the high-speed mode if the host is high-speed capable.
0
1
reserved, do not use this configuration
1
0
reserved, do not use this configuration
1
1
Full-speed: the peripheral remains in full-speed mode whatever is the host speed capability.
• RMWKUP: Remote Wake-Up
Writing a one to this bit will send an upstream resume to the host for a remote wake-up.
Writing a zero to this bit has no effect.
This bit is cleared when the USBB receive a USB reset or once the upstream resume has been sent.
• DETACH: Detach
Writing a one to this bit will physically detach the device (disconnect internal pull-up resistor from D+ and D-).
Writing a zero to this bit will reconnect the device.
• ADDEN: Address Enable
Writing a one to this bit will activate the UADD field (USB address).
Writing a zero to this bit has no effect.
This bit is cleared when a USB reset is received.
• UADD: USB Address
This field contains the device address.
This field is cleared when a USB reset is received.
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26.8.2.2
Device Global Interrupt Register
Register Name:
UDINT
Access Type:
Read-Only
Offset:
0x0004
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
DMA7INT
DMA6INT
DMA5INT
DMA4INT
DMA3INT
DMA2INT
DMA1INT
-
23
22
21
20
19
18
17
16
-
-
-
-
EP7INT
EP6INT
EP5INT
EP4INT
15
14
13
12
11
10
9
8
EP3INT
EP2INT
EP1INT
EP0INT
-
-
-
-
7
6
5
4
3
2
1
0
-
UPRSM
EORSM
WAKEUP
EORST
SOF
MSOF
SUSP
• DMAnINT: DMA Channel n Interrupt
This bit is set when an interrupt is triggered by the DMA channel n. This triggers a USB interrupt if DMAnINTE is one.
This bit is cleared when the UDDMAnSTATUS interrupt source is cleared.
• EPnINT: Endpoint n Interrupt
This bit is set when an interrupt is triggered by the endpoint n (UESTAn, UECONn). This triggers a USB interrupt if EPnINTE is
one.
This bit is cleared when the interrupt source is serviced.
• UPRSM: Upstream Resume Interrupt
This bit is set when the USBB sends a resume signal called “Upstream Resume”. This triggers a USB interrupt if UPRSME is
one.
This bit is cleared when the UDINTCLR.UPRSMC bit is written to one to acknowledge the interrupt (USB clock inputs must be
enabled before).
• EORSM: End of Resume Interrupt
This bit is set when the USBB detects a valid “End of Resume” signal initiated by the host. This triggers a USB interrupt if
EORSME is one.
This bit is cleared when the UDINTCLR.EORSMC bit is written to one to acknowledge the interrupt.
• WAKEUP: Wake-Up Interrupt
This bit is set when the USBB is reactivated by a filtered non-idle signal from the lines (not by an upstream resume). This
triggers an interrupt if WAKEUPE is one.
This bit is cleared when the UDINTCLR.WAKEUPC bit is written to one to acknowledge the interrupt (USB clock inputs must be
enabled before).
This bit is cleared when the Suspend (SUSP) interrupt bit is set.
This interrupt is generated even if the clock is frozen by the FRZCLK bit.
• EORST: End of Reset Interrupt
This bit is set when a USB “End of Reset” has been detected. This triggers a USB interrupt if EORSTE is one.
This bit is cleared when the UDINTCLR.EORSTC bit is written to one to acknowledge the interrupt.
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• SOF: Start of Frame Interrupt
This bit is set when a USB “Start of Frame” PID (SOF) has been detected (every 1 ms). This triggers a USB interrupt if SOFE is
one. The FNUM field is updated. In High-speed mode, the MFNUM field is cleared.
This bit is cleared when the UDINTCLR.SOFC bit is written to one to acknowledge the interrupt.
• MSOF: Micro Start of Frame Interrupt
This bit is set in High-speed mode when a USB “Micro Start of Frame” PID (SOF) has been detected (every 125 us). This
triggers a USB interrupt if MSOFE is one. The MFNUM field is updated. The FNUM field is unchanged.
This bit is cleared when the UDINTCLR.MSOFC bit is written to one to acknowledge the interrupt.
• SUSP: Suspend Interrupt
This bit is set when a USB “Suspend” idle bus state has been detected for 3 frame periods (J state for 3 ms). This triggers a
USB interrupt if SUSPE is one.
This bit is cleared when the UDINTCLR.SUSPC bit is written to one to acknowledge the interrupt.
This bit is cleared when the Wake-Up (WAKEUP) interrupt bit is set.
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26.8.2.3
Device Global Interrupt Clear Register
Register Name:
UDINTCLR
Access Type:
Write-Only
Offset:
0x0008
Read Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
UPRSMC
EORSMC
WAKEUPC
EORSTC
SOFC
MSOFC
SUSPC
Writing a one to a bit in this register will clear the corresponding bit in UDINT.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
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26.8.2.4
Device Global Interrupt Set Register
Register Name:
UDINTSET
Access Type:
Write-Only
Offset:
0x000C
Read Value:
0x00000000
31
30
29
28
27
26
25
24
DMA7INTS
DMA6INTS
DMA5INTS
DMA4INTS
DMA3INTS
DMA2INTS
DMA1INTS
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
UPRSMS
EORSMS
WAKEUPS
EORSTS
SOFS
MSOFS
SUSPS
Writing a one to a bit in this register will set the corresponding bit in UDINT, what may be useful for test or debug purposes.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
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26.8.2.5
Device Global Interrupt Enable Register
Register Name:
UDINTE
Access Type:
Read-Only
Offset:
0x0010
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
DMA7INTE
DMA6INTE
DMA5INTE
DMA4INTE
DMA3INTE
DMA2INTE
DMA1INTE
-
23
22
21
20
19
18
17
16
-
-
-
-
EP7INTE
EP6INTE
EP5INTE
EP4INTE
15
14
13
12
11
10
9
8
EP3INTE
EP2INTE
EP1INTE
EP0INTE
-
-
-
-
7
6
5
4
3
2
1
0
-
UPRSME
EORSME
WAKEUPE
EORSTE
SOFE
MSOFE
SUSPE
1: The corresponding interrupt is enabled.
0: The corresponding interrupt is disabled.
A bit in this register is set when the corresponding bit in UDINTESET is written to one.
A bit in this register is cleared when the corresponding bit in UDINTECLR is written to one.
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26.8.2.6
Device Global Interrupt Enable Clear Register
Register Name:
UDINTECLR
Access Type:
Write-Only
Offset:
0x0014
Read Value:
0x00000000
31
30
29
28
27
26
25
24
DMA7INTEC
DMA6INTEC
DMA5INTEC
DMA4INTEC
DMA3INTEC
DMA2INTEC
DMA1INTEC
-
23
22
21
20
19
18
17
16
-
-
-
-
EP7INTEC
EP6INTEC
EP5INTEC
EP4INTEC
15
14
13
12
11
10
9
8
EP3INTEC
EP2INTEC
EP1INTEC
EP0INTEC
-
-
-
-
7
6
5
4
3
2
1
0
-
UPRSMEC
EORSMEC
WAKEUPEC
EORSTEC
SOFEC
MSOFEC
SUSPEC
Writing a one to a bit in this register will clear the corresponding bit in UDINTE.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
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26.8.2.7
Device Global Interrupt Enable Set Register
Register Name:
UDINTESET
Access Type:
Write-Only
Offset:
0x0018
Read Value:
0x00000000
31
30
29
28
27
26
25
24
DMA7INTES
DMA6INTES
DMA5INTES
DMA4INTES
DMA3INTES
DMA2INTES
DMA1INTES
-
23
22
21
20
19
18
17
16
-
-
-
-
EP7INTES
EP6INTES
EP5INTES
EP4INTES
15
14
13
12
11
10
9
8
EP3INTES
EP2INTES
EP1INTES
EP0INTES
-
-
-
-
7
6
5
4
3
2
1
0
-
UPRSMES
EORSMES
WAKEUPES
EORSTES
SOFES
MSOFES
SUSPES
Writing a one to a bit in this register will set the corresponding bit in UDINTE.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
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26.8.2.8
Endpoint Enable/Reset Register
Register Name:
UERST
Access Type:
Read/Write
Offset:
0x001C
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
EPRST7
EPRST6
EPRST5
EPRST4
EPRST3
EPRST2
EPRST1
EPRST0
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
EPEN7
EPEN6
EPEN5
EPEN4
EPEN3
EPEN2
EPEN1
EPEN0
• EPRSTn: Endpoint n Reset
Writing a one to this bit will reset the endpoint n FIFO prior to any other operation, upon hardware reset or when a USB bus
reset has been received. This resets the endpoint n registers (UECFGn, UESTAn, UECONn) but not the endpoint configuration
(ALLOC, EPBK, EPSIZE, EPDIR, EPTYPE).
All the endpoint mechanism (FIFO counter, reception, transmission, etc.) is reset apart from the Data Toggle Sequence field
(DTSEQ) which can be cleared by setting the RSTDT bit (by writing a one to the RSTDTS bit).
The endpoint configuration remains active and the endpoint is still enabled.
Writing a zero to this bit will complete the reset operation and start using the FIFO.
This bit is cleared upon receiving a USB reset.
• EPENn: Endpoint n Enable
1: The endpoint n is enabled.
0: The endpoint n is disabled, what forces the endpoint n state to inactive (no answer to USB requests) and resets the endpoint
n registers (UECFGn, UESTAn, UECONn) but not the endpoint configuration (ALLOC, EPBK, EPSIZE, EPDIR, EPTYPE).
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26.8.2.9
Device Frame Number Register
Register Name:
UDFNUM
Access Type:
Read-Only
Offset:
0x0020
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
FNCERR
-
7
6
2
1
0
FNUM[10:5]
5
FNUM[4:0]
4
3
MFNUM
• FNCERR: Frame Number CRC Error
This bit is set when a corrupted frame number (or micro-frame number) is received. This bit and the SOF (or MSOF) interrupt bit
are updated at the same time.
This bit is cleared upon receiving a USB reset.
• FNUM: Frame Number
This field contains the 11-bit frame number information. It is provided in the last received SOF packet.
This field is cleared upon receiving a USB reset.
FNUM is updated even if a corrupted SOF is received.
• MFNUM: Micro Frame Number
This field contains the 3-bit micro frame number information. It is provided in the last received MSOF packet.
This field is cleared at the beginning of each start of frame (SOF interrupt) or upon receiving a USB reset.
MFNUM is updated even if a corrupted MSOF is received.
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26.8.2.10
Endpoint n Configuration Register
Register Name:
UECFGn, n in [0..7]
Access Type:
Read/Write
Offset:
0x0100 + (n * 0x04)
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
AUTOSW
EPDIR
2
1
0
ALLOC
-
-
NBTRANS
7
6
EPTYPE
5
-
4
EPSIZE
3
EPBK
• NBTRANS: Number of transaction per microframe for isochronous endpoint
This field shall be written to the number of transaction per microframe to perform high-bandwidth isochronous transfer
This field can be written only for endpoint that have this capability (see UFEATURES register, ENHBISOn bit). This field is 0
otherwise.
This field is irrelevant for non-isochronous endpoint.
NBTRANS
Number of transaction
0
0
reserved to endpoint that does not have the high-bandwidth isochronous capability.
0
1
default value: one transaction per micro-frame.
1
0
2 transactions per micro-frame. This endpoint should be configured as double-bank.
1
1
3 transactions per micro-frame. This endpoint should be configured as triple-bank.
• EPTYPE: Endpoint Type
This field shall be written to select the endpoint type:
EPTYPE
Endpoint Type
0
0
Control
0
1
Isochronous
1
0
Bulk
1
1
Interrupt
This field is cleared upon receiving a USB reset.
• AUTOSW: Automatic Switch
This bit is cleared upon receiving a USB reset.
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1: The automatic bank switching is enabled.
0: The automatic bank switching is disabled.
• EPDIR: Endpoint Direction
This bit is cleared upon receiving a USB reset.
1: The endpoint direction is IN (nor for control endpoints).
0: The endpoint direction is OUT.
• EPSIZE: Endpoint Size
This field shall be written to select the size of each endpoint bank:
EPSIZE
Endpoint Size
0
0
0
8 bytes
0
0
1
16 bytes
0
1
0
32 bytes
0
1
1
64 bytes
1
0
0
128 bytes
1
0
1
256 bytes
1
1
0
512 bytes
1
1
1
1024 bytes
This field is cleared upon receiving a USB reset (except for the endpoint 0).
• EPBK: Endpoint Banks
This field shall be written to select the number of banks for the endpoint:
EPBK
Endpoint Banks
0
0
1 (single-bank endpoint)
0
1
2 (double-bank endpoint)
1
0
3 (triple-bank endpoint)
1
1
Reserved
For control endpoints, a single-bank endpoint (0b00) shall be selected.
This field is cleared upon receiving a USB reset (except for the endpoint 0).
• ALLOC: Endpoint Memory Allocate
Writing a one to this bit will allocate the endpoint memory. The user should check the CFGOK bit to know whether the allocation
of this endpoint is correct.
Writing a zero to this bit will free the endpoint memory.
This bit is cleared upon receiving a USB reset (except for the endpoint 0).
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26.8.2.11
Endpoint n Status Register
Register Name:
UESTAn, n in [0..7]
Access Type:
Read-Only 0x0100
Offset:
0x0130 + (n * 0x04)
Reset Value:
0x00000100
31
30
29
28
26
25
24
19
18
17
16
-
CFGOK
CTRLDIR
RWALL
11
10
9
8
-
ERRORTRANS
3
2
1
0
NAKINI/
NAKOUTI/
HBISOFLUSHI
HBISOINERRI
RXSTPI/
UNDERFI
RXOUTI
TXINI
-
27
BYCT
23
22
21
20
BYCT
15
14
13
CURRBK
12
NBUSYBK
7
6
5
SHORT
PACKET
STALLEDI/
CRCERRI
OVERFI
4
DTSEQ
• BYCT: Byte Count
This field is set with the byte count of the FIFO.
For IN endpoints, incremented after each byte written by the software into the endpoint and decremented after each byte sent to
the host.
For OUT endpoints, incremented after each byte received from the host and decremented after each byte read by the software
from the endpoint.
This field may be updated one clock cycle after the RWALL bit changes, so the user should not poll this field as an interrupt bit.
• CFGOK: Configuration OK Status
This bit is updated when the ALLOC bit is written to one.
This bit is set if the endpoint n number of banks (EPBK) and size (EPSIZE) are correct compared to the maximal allowed
number of banks and size for this endpoint and to the maximal FIFO size (i.e. the DPRAM size).
If this bit is cleared, the user shall rewrite correct values to the EPBK and EPSIZE fields in the UECFGn register.
• CTRLDIR: Control Direction
This bit is set after a SETUP packet to indicate that the following packet is an IN packet.
This bit is cleared after a SETUP packet to indicate that the following packet is an OUT packet.
Writing a zero or a one to this bit has no effect.
• RWALL: Read/Write Allowed
This bit is set for IN endpoints when the current bank is not full, i.e., the user can write further data into the FIFO.
This bit is set for OUT endpoints when the current bank is not empty, i.e., the user can read further data from the FIFO.
This bit is never set if STALLRQ is one or in case of error.
This bit is cleared otherwise.
This bit shall not be used for control endpoints.
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• CURRBK: Current Bank
This bit is set for non-control endpoints, to indicate the current bank:
CURRBK
Current Bank
0
0
Bank0
0
1
Bank1
1
0
Bank2
1
1
Reserved
This field may be updated one clock cycle after the RWALL bit changes, so the user should not poll this field as an interrupt bit.
• NBUSYBK: Number of Busy Banks
This field is set to indicate the number of busy banks:
NBUSYBK
Number of Busy Banks
0
0
0 (all banks free)
0
1
1
1
0
2
1
1
3
For IN endpoints, it indicates the number of banks filled by the user and ready for IN transfer. When all banks are free, this
triggers an EPnINT interrupt if NBUSYBKE is one.
For OUT endpoints, it indicates the number of banks filled by OUT transactions from the host. When all banks are busy, this
triggers an EPnINT interrupt if NBUSYBKE is one.
When the FIFOCON bit is cleared (by writing a one to the FIFOCONC bit) to validate a new bank, this field is updated two or
three clock cycles later to calculate the address of the next bank.
An EPnINT interrupt is triggered if:
- for IN endpoint, NBUSYBKE is one and all the banks are free.
- for OUT endpoint, NBUSYBKE is one and all the banks are busy.
• ERRORTRANS: High-bandwidth isochronous OUT endpoint transaction error Interrupt
This bit is set when a transaction error occurs during the current micro-frame (the data toggle sequencing does not respect the
usb 2.0 standard). This triggers an EPnINT interrupt if ERRORTRANSE is one.
This bit is set as long as the current bank (CURRBK) belongs to the bad n-transactions (n=1,2 or 3) transferred during the
micro-frame. Shall be cleared by software by clearing (at least once) the FIFOCON bit to switch to the bank that belongs to the
next n-transactions (next micro-frame).
• DTSEQ: Data Toggle Sequence
This field is set to indicate the PID of the current bank:
DTSEQ
Data Toggle Sequence
0
0
Data0
0
1
Data1
1
0
Data2 (for high-bandwidth isochronous endpoint)
1
1
MData (for high-bandwidth isochronous endpoint)
For IN transfers, it indicates the data toggle sequence that will be used for the next packet to be sent. This is not relative to the
current bank.
For OUT transfers, this value indicates the last data toggle sequence received on the current bank.
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•
•
•
•
•
•
•
•
•
By default DTSEQ is 0b01, as if the last data toggle sequence was Data1, so the next sent or expected data toggle sequence
should be Data0.
For High-bandwidth isochronous endpoint, an EPnINT interrupt is triggered if:
- MDATAE is one and a MData packet has been received (DTSEQ=MData and RXOUTI is one).
- DATAXE is one and a Data0/1/2 packet has been received (DTSEQ=Data0/1/2 and RXOUTI is one)
SHORTPACKET: Short Packet Interrupt
This bit is set for non-control OUT endpoints, when a short packet has been received.
This bit is set for non-control IN endpoints, a short packet is transmitted upon ending a DMA transfer, thus signaling an end of
isochronous frame or a bulk or interrupt end of transfer, this only if the End of DMA Buffer Output Enable (DMAENDEN) bit and
the Automatic Switch (AUTOSW) bit are written to one.
This triggers an EPnINT interrupt if SHORTPACKETE is one.
This bit is cleared when the SHORTPACKETC bit is written to one. This will acknowledge the interrupt.
STALLEDI: STALLed Interrupt
This bit is set to signal that a STALL handshake has been sent. To do that, the software has to set the STALLRQ bit (by writing a
one to the STALLRQS bit). This triggers an EPnINT interrupt if STALLEDE is one.
This bit is cleared when the STALLEDIC bit is written to one. This will acknowledge the interrupt.
CRCERRI: CRC Error Interrupt
This bit is set to signal that a CRC error has been detected in an isochronous OUT endpoint. The OUT packet is stored in the
bank as if no CRC error had occurred. This triggers an EPnINT interrupt if CRCERRE is one.
This bit is cleared when the CRCERRIC bit is written to one. This will acknowledge the interrupt.
OVERFI: Overflow Interrupt
This bit is set when an overflow error occurs. This triggers an EPnINT interrupt if OVERFE is one.
For all endpoint types, an overflow can occur during OUT stage if the host attempts to write into a bank that is too small for the
packet. The packet is acknowledged and the RXOUTI bit is set as if no overflow had occurred. The bank is filled with all the first
bytes of the packet that fit in.
This bit is cleared when the OVERFIC bit is written to one. This will acknowledge the interrupt.
NAKINI: NAKed IN Interrupt
This bit is set when a NAK handshake has been sent in response to an IN request from the host. This triggers an EPnINT
interrupt if NAKINE is one.
This bit is cleared when the NAKINIC bit is written to one. This will acknowledge the interrupt.
HBISOFLUSHI: High Bandwidth Isochronous IN Flush Interrupt
This bit is set, for High-bandwidth isochronous IN endpoint (with NBTRANS=2 or 3), at the end of the micro-frame, if less than N
transaction has been completed by the USBB without underflow error. This may occur in case of a missing IN token. In this
case, the bank are flushed out to ensure the data synchronization between the host and the device. This triggers an EPnINT
interrupt if HBISOFLUSHE is one.
This bit is cleared when the HBISOFLUSHIC bit is written to one. This will acknowledge the interrupt.
NAKOUTI: NAKed OUT Interrupt
This bit is set when a NAK handshake has been sent in response to an OUT request from the host. This triggers an EPnINT
interrupt if NAKOUTE is one.
This bit is cleared when the NAKOUTIC bit is written to one. This will acknowledge the interrupt.
HBISOINERRI: High bandwidth isochronous IN Underflow Error Interrupt
This bit is set, for High-bandwidth isochronous IN endpoint (with NBTRANS=2 or 3), at the end of the microframe, if less than N
bank was written by the cpu within this micro-frame. This triggers an EPnINT interrupt if HBISOINERRE is one.
This bit is cleared when the HBISOINERRIC bit is written to one. This will acknowledge the interrupt.
UNDERFI: Underflow Interrupt
This bit is set, for isochronous IN/OUT endpoints, when an underflow error occurs. This triggers an EPnINT interrupt if
UNDERFE is one.
An underflow can occur during IN stage if the host attempts to read from an empty bank. A zero-length packet is then
automatically sent by the USBB.
An underflow can also occur during OUT stage if the host sends a packet while the bank is already full. Typically, the CPU is not
fast enough. The packet is lost.
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Shall be cleared by writing a one to the UNDERFIC bit. This will acknowledge the interrupt.
This bit is inactive (cleared) for bulk and interrupt IN/OUT endpoints and it means RXSTPI for control endpoints.
• RXSTPI: Received SETUP Interrupt
This bit is set, for control endpoints, to signal that the current bank contains a new valid SETUP packet. This triggers an EPnINT
interrupt if RXSTPE is one.
Shall be cleared by writing a one to the RXSTPIC bit. This will acknowledge the interrupt and free the bank.
This bit is inactive (cleared) for bulk and interrupt IN/OUT endpoints and it means UNDERFI for isochronous IN/OUT endpoints.
• RXOUTI: Received OUT Data Interrupt
This bit is set, for control endpoints, when the current bank contains a bulk OUT packet (data or status stage). This triggers an
EPnINT interrupt if RXOUTE is one.
Shall be cleared for control end points, by writing a one to the RXOUTIC bit. This will acknowledge the interrupt and free the
bank.
This bit is set for isochronous, bulk and, interrupt OUT endpoints, at the same time as FIFOCON when the current bank is full.
This triggers an EPnINT interrupt if RXOUTE is one.
Shall be cleared for isochronous, bulk and, interrupt OUT endpoints, by writing a one to the RXOUTIC bit. This will acknowledge
the interrupt, what has no effect on the endpoint FIFO.
The user then reads from the FIFO and clears the FIFOCON bit to free the bank. If the OUT endpoint is composed of multiple
banks, this also switches to the next bank. The RXOUTI and FIFOCON bits are set/cleared in accordance with the status of the
next bank.
RXOUTI shall always be cleared before clearing FIFOCON.
This bit is inactive (cleared) for isochronous, bulk and interrupt IN endpoints.
• TXINI: Transmitted IN Data Interrupt
This bit is set for control endpoints, when the current bank is ready to accept a new IN packet. This triggers an EPnINT interrupt
if TXINE is one.
This bit is cleared when the TXINIC bit is written to one. This will acknowledge the interrupt and send the packet.
This bit is set for isochronous, bulk and interrupt IN endpoints, at the same time as FIFOCON when the current bank is free.
This triggers an EPnINT interrupt if TXINE is one.
This bit is cleared when the TXINIC bit is written to one. This will acknowledge the interrupt, what has no effect on the endpoint
FIFO.
The user then writes into the FIFO and clears the FIFOCON bit to allow the USBB to send the data. If the IN endpoint is
composed of multiple banks, this also switches to the next bank. The TXINI and FIFOCON bits are set/cleared in accordance
with the status of the next bank.
TXINI shall always be cleared before clearing FIFOCON.
This bit is inactive (cleared) for isochronous, bulk and interrupt OUT endpoints.
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26.8.2.12
Endpoint n Status Clear Register
Register Name:
UESTAnCLR, n in [0..7]
Access Type:
Write-Only
Offset:
0x0160 + (n * 0x04)
Read Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
SHORT
PACKETC
STALLEDIC/
CRCERRIC
OVERFIC
NAKINIC/
NAKOUTIC/
HBISOFLUSHIC
HBISOINERRIC
RXSTPIC/
UNDERFIC
RXOUTIC
TXINIC
Writing a one to a bit in this register will clear the corresponding bit in UESTA.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
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26.8.2.13
Endpoint n Status Set Register
Register Name:
UESTAnSET, n in [0..7]
Access Type:
Write-Only
Offset:
0x0190 + (n * 0x04)
Read Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
NBUSYBKS
-
-
7
6
5
4
3
2
1
0
SHORT
PACKETS
STALLEDIS/
CRCERRIS
OVERFIS
NAKINIS/
NAKOUTIS/
HBISOFLUSHIS
HBISOINERRIS
RXSTPIS/
UNDERFIS
RXOUTIS
TXINIS
-
Writing a one to a bit in this register will set the corresponding bit in UESTA, what may be useful for test or debug purposes.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
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26.8.2.14
Endpoint n Control Register
Register Name:
UECONn, n in [0..7]
Access Type:
Read-Only
Offset:
0x01C0 + (n * 0x04)
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
STALLRQ
RSTDT
NYETDIS
EPDISHDMA
15
14
13
12
11
10
9
8
-
FIFOCON
KILLBK
NBUSYBKE
-
ERRORTRANSE
DATAXE
MDATAE
7
6
5
4
3
2
1
0
SHORT
PACKETE
STALLEDE/
CRCERRE
OVERFE
NAKINE/
NAKOUTE/
HBISOFLUSHE
HBISOINERRE
RXSTPE/
UNDERFE
RXOUTE
TXINE
• STALLRQ: STALL Request
This bit is set when the STALLRQS bit is written to one. This will request to send a STALL handshake to the host.
This bit is cleared when a new SETUP packet is received or when the STALLRQC bit is written to zero.
• RSTDT: Reset Data Toggle
This bit is set when the RSTDTS bit is written to one. This will clear the data toggle sequence, i.e., set to Data0 the data toggle
sequence of the next sent (IN endpoints) or received (OUT endpoints) packet.
This bit is cleared instantaneously.
The user does not have to wait for this bit to be cleared.
• NYETDIS: NYET token disable
This bit is set when the NYETDISS bit is written to one. This will send a ACK handshake instead of a NYET handshake in highspeed mode.
This bit is cleared when the NYETDISC bit is written to one.This will let the USBB handling the high-speed handshake following
the usb 2.0 standard.
• EPDISHDMA: Endpoint Interrupts Disable HDMA Request Enable
This bit is set when the EPDISHDMAS is written to one. This will pause the on-going DMA channel n transfer on any Endpoint n
interrupt (EPnINT), whatever the state of the Endpoint n Interrupt Enable bit (EPnINTE).
The user then has to acknowledge or to disable the interrupt source (e.g. RXOUTI) or to clear the EPDISHDMA bit (by writing a
one to the EPDISHDMAC bit) in order to complete the DMA transfer.
In ping-pong mode, if the interrupt is associated to a new system-bank packet (e.g. Bank1) and the current DMA transfer is
running on the previous packet (Bank0), then the previous-packet DMA transfer completes normally, but the new-packet DMA
transfer will not start (not requested).
If the interrupt is not associated to a new system-bank packet (NAKINI, NAKOUTI, etc.), then the request cancellation may
occur at any time and may immediately pause the current DMA transfer.
This may be used for example to identify erroneous packets, to prevent them from being transferred into a buffer, to complete a
DMA transfer by software after reception of a short packet, etc.
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• FIFOCON: FIFO Control
For control endpoints:
The FIFOCON and RWALL bits are irrelevant. The software shall therefore never use them on these endpoints. When read,
their value is always 0.
For IN endpoints:
This bit is set when the current bank is free, at the same time as TXINI.
This bit is cleared (by writing a one to the FIFOCONC bit) to send the FIFO data and to switch to the next bank.
For OUT endpoints:
This bit is set when the current bank is full, at the same time as RXOUTI.
This bit is cleared (by writing a one to the FIFOCONC bit) to free the current bank and to switch to the next bank.
• KILLBK: Kill IN Bank
This bit is set when the KILLBKS bit is written to one. This will kill the last written bank.
This bit is cleared when the bank is killed.
Caution: The bank is really cleared when the “kill packet” procedure is accepted by the USBB core. This bit is automatically
cleared after the end of the procedure:
The bank is really killed: NBUSYBK is decremented.
The bank is not cleared but sent (IN transfer): NBUSYBK is decremented.
The bank is not cleared because it was empty.
The user shall wait for this bit to be cleared before trying to kill another packet.
This kill request is refused if at the same time an IN token is coming and the last bank is the current one being sent on the USB
line. If at least 2 banks are ready to be sent, there is no problem to kill a packet even if an IN token is coming. Indeed, in this
case, the current bank is sent (IN transfer) while the last bank is killed.
• NBUSYBKE: Number of Busy Banks Interrupt Enable
This bit is set when the NBUSYBKES bit is written to one. This will enable the Number of Busy Banks interrupt (NBUSYBK).
This bit is cleared when the NBUSYBKEC bit is written to zero. This will disable the Number of Busy Banks interrupt
(NBUSYBK).
• ERRORTRANSE: Transaction Error Interrupt Enable
This bit is set when the ERRORTRANSES bit is written to one. This will enable the transaction error interrupt (ERRORTRANS).
This bit is cleared when the ERRORTRANSEC bit is written to one. This will disable the transaction error interrupt
(ERRORTRANS).
• DATAXE: DataX Interrupt Enable
This bit is set when the DATAXES bit is written to one. This will enable the DATAX interrupt. (see DTSEQ bits)
This bit is cleared when the DATAXEC bit is written to one. This will disable the DATAX interrupt.
• MDATAE: MData Interrupt Enable
This bit is set when the MDATAES bit is written to one. This will enable the Multiple DATA interrupt. (see DTSEQ bits)
This bit is cleared when the MDATAEC bit is written to one. This will disable the Multiple DATA interrupt.
• SHORTPACKETE: Short Packet Interrupt Enable
This bit is set when the SHORTPACKETES bit is written to one. This will enable the Short Packet interrupt (SHORTPACKET).
This bit is cleared when the SHORTPACKETEC bit is written to one. This will disable the Short Packet interrupt
(SHORTPACKET).
• STALLEDE: STALLed Interrupt Enable
This bit is set when the STALLEDES bit is written to one. This will enable the STALLed interrupt (STALLEDI).
This bit is cleared when the STALLEDEC bit is written to one. This will disable the STALLed interrupt (STALLEDI).
• CRCERRE: CRC Error Interrupt Enable
This bit is set when the CRCERRES bit is written to one. This will enable the CRC Error interrupt (CRCERRI).
This bit is cleared when the CRCERREC bit is written to one. This will disable the CRC Error interrupt (CRCERRI).
• OVERFE: Overflow Interrupt Enable
This bit is set when the OVERFES bit is written to one. This will enable the Overflow interrupt (OVERFI).
This bit is cleared when the OVERFEC bit is written to one. This will disable the Overflow interrupt (OVERFI).
• NAKINE: NAKed IN Interrupt Enable
This bit is set when the NAKINES bit is written to one. This will enable the NAKed IN interrupt (NAKINI).
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This bit is cleared when the NAKINEC bit is written to one. This will disable the NAKed IN interrupt (NAKINI).
• HBISOFLUSHE: High Bandwidth Isochronous IN Flush Interrupt Enable
This bit is set when the HBISOFLUSHES bit is written to one. This will enable the HBISOFLUSHI interrupt.
This bit is cleared when the HBISOFLUSHEC bit disable the HBISOFLUSHI interrupt.
• NAKOUTE: NAKed OUT Interrupt Enable
This bit is set when the NAKOUTES bit is written to one. This will enable the NAKed OUT interrupt (NAKOUTI).
This bit is cleared when the NAKOUTEC bit is written to one. This will disable the NAKed OUT interrupt (NAKOUTI).
• HBISOINERRE: High Bandwidth Isochronous IN Error Interrupt Enable
This bit is set when the HBISOINERRES bit is written to one. This will enable the HBISOINERRI interrupt.
This bit is cleared when the HBISOINERREC bit disable the HBISOINERRI interrupt.
• RXSTPE: Received SETUP Interrupt Enable
This bit is set when the RXSTPES bit is written to one. This will enable the Received SETUP interrupt (RXSTPI).
This bit is cleared when the RXSTPEC bit is written to one. This will disable the Received SETUP interrupt (RXSTPI).
• UNDERFE: Underflow Interrupt Enable
This bit is set when the UNDERFES bit is written to one. This will enable the Underflow interrupt (UNDERFI).
This bit is cleared when the UNDERFEC bit is written to one. This will disable the Underflow interrupt (UNDERFI).
• RXOUTE: Received OUT Data Interrupt Enable
This bit is set when the RXOUTES bit is written to one. This will enable the Received OUT Data interrupt (RXOUT).
This bit is cleared when the RXOUTEC bit is written to one. This will disable the Received OUT Data interrupt (RXOUT).
• TXINE: Transmitted IN Data Interrupt Enable
This bit is set when the TXINES bit is written to one. This will enable the Transmitted IN Data interrupt (TXINI).
This bit is cleared when the TXINEC bit is written to one. This will disable the Transmitted IN Data interrupt (TXINI).
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26.8.2.15
Endpoint n Control Clear Register
Register Name:
UECONnCLR, n in [0..7]
Access Type:
Write-Only
Offset:
0x0220 + (n * 0x04)
Read Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
STALLRQC
-
NYETDISC
EPDISHDMAC
15
14
13
12
11
10
9
8
-
FIFOCONC
-
NBUSYBKEC
-
ERRORTRANSEC
DATAXEC
MDATEC
7
6
5
4
3
2
1
0
SHORT
PACKETEC
STALLEDEC/
CRCERREC
OVERFEC
NAKINEC/
NAKOUTEC/
HBISOFLUSHEC
HBISOINERREC
RXSTPEC/
UNDERFEC
RXOUTEC
TXINEC
Writing a one to a bit in this register will clear the corresponding bit in UECONn.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
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26.8.2.16
Endpoint n Control Set Register
Register Name:
UECONnSET, n in [0..7]
Access Type:
Write-Only
Offset:
0x01F0 + (n * 0x04)
Read Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
STALLRQS
RSTDTS
NYETDISS
EPDISHDMAS
15
14
13
12
11
10
9
8
-
-
KILLBKS
NBUSYBKES
-
ERRORTRANSES
DATAXES
MDATES
7
6
5
4
3
2
1
0
SHORT
PACKETES
STALLEDES/
CRCERRES
OVERFES
NAKINES/
NAKOUTES/
HBISOFLUSHES
HBISOINERRES
RXSTPES/
UNDERFES
RXOUTES
TXINES
Writing a one to a bit in this register will set the corresponding bit in UECONn.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
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26.8.2.17
Device DMA Channel n Next Descriptor Address Register
Register Name:
UDDMAnNEXTDESC, n in [1..7]
Access Type:
Read/Write
Offset:
0x0310 + (n - 1) * 0x10
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
18
17
16
10
9
8
3
2
1
0
-
-
-
-
NXTDESCADDR[31:24]
23
22
21
20
19
NXTDESCADDR[23:16]
15
14
13
12
11
NXTDESCADDR[15:8]
7
6
5
NXTDESCADDR[7:4]
4
• NXTDESCADDR: Next Descriptor Address
This field contains the bits 31:4 of the 16-byte aligned address of the next channel descriptor to be processed.
This field is written either or by descriptor loading.
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26.8.2.18
Device DMA Channel n HSB Address Register
Register Name:
UDDMAnADDR, n in [1..7]
Access Type:
Read/Write
Offset:
0x0314 + (n - 1) * 0x10
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
18
17
16
10
9
8
2
1
0
HSBADDR[31:24]
23
22
21
20
19
HSBADDR[23:16]
15
14
13
12
11
HSBADDR[15:8]
7
6
5
4
3
HSBADDR[7:0]
• HSBADDR: HSB Address
This field determines the HSB bus current address of a channel transfer.
The address written to the HSB address bus is HSBADDR rounded down to the nearest word-aligned address, i.e.,
HSBADDR[1:0] is considered as 0b00 since only word accesses are performed.
Channel HSB start and end addresses may be aligned on any byte boundary.
The user may write this field only when the Channel Enabled bit (CHEN) of the UDDMAnSTATUS register is cleared.
This field is updated at the end of the address phase of the current access to the HSB bus. It is incremented of the HSB access
byte-width.
The HSB access width is 4 bytes, or less at packet start or end if the start or end address is not aligned on a word boundary.
The packet start address is either the channel start address or the next channel address to be accessed in the channel buffer.
The packet end address is either the channel end address or the latest channel address accessed in the channel buffer.
The channel start address is written or loaded from the descriptor, whereas the channel end address is either determined by the
end of buffer or the end of USB transfer if the Buffer Close Input Enable bit (BUFFCLOSEINEN) is set.
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26.8.2.19
Device DMA Channel n Control Register
Register Name:
UDDMAnCONTROL, n in [1..7]
Access Type:
Read/Write
Offset:
0x0318 + (n - 1) * 0x10
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
18
17
16
CHBYTELENGTH[15:8]
23
22
21
20
19
CHBYTELENGTH[7:0]
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
BURSTLOCKEN
DESCLDIRQEN
EOBUFFIRQEN
EOTIRQEN
DMAENDEN
BUFFCLOSE
INEN
LDNXTCH
DESCEN
CHEN
• CHBYTELENGTH: Channel Byte Length
This field determines the total number of bytes to be transferred for this buffer.
The maximum channel transfer size 64kB is reached when this field is zero (default value).
If the transfer size is unknown, the transfer end is controlled by the peripheral and this field should be written to zero.
This field can be written or descriptor loading only after the UDDMAnSTATUS.CHEN bit has been cleared, otherwise this field is
ignored.
• BURSTLOCKEN: Burst Lock Enable
1: The USB data burst is locked for maximum optimization of HSB busses bandwidth usage and maximization of fly-by duration.
0: The DMA never locks the HSB access.
• DESCLDIRQEN: Descriptor Loaded Interrupt Enable
1: The Descriptor Loaded interrupt is enabled.This interrupt is generated when a Descriptor has been loaded from the system
bus.
0: The Descriptor Loaded interrupt is disabled.
• EOBUFFIRQEN: End of Buffer Interrupt Enable
1: The end of buffer interrupt is enabled.This interrupt is generated when the channel byte count reaches zero.
0: The end of buffer interrupt is disabled.
• EOTIRQEN: End of USB Transfer Interrupt Enable
1: The end of usb OUT data transfer interrupt is enabled. This interrupt is generated only if the BUFFCLOSEINEN bit is set.
0: The end of usb OUT data transfer interrupt is disabled.
• DMAENDEN: End of DMA Buffer Output Enable
Writing a one to this bit will properly complete the usb transfer at the end of the dma transfer.
For IN endpoint, it means that a short packet (or a Zero Length Packet) will be sent to the USB line to properly closed the usb
transfer at the end of the dma transfer.
For OUT endpoint, it means that all the banks will be properly released. (NBUSYBK=0) at the end of the dma transfer.
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• BUFFCLOSEINEN: Buffer Close Input Enable
For Bulk and Interrupt endpoint, writing a one to this bit will automatically close the current DMA transfer at the end of the USB
OUT data transfer (received short packet).
For Full-speed Isochronous, it does not make sense, so BUFFCLOSEINEN should be left to zero.
For high-speed OUT isochronous, it may make sense. In that case, if BUFFCLOSEINEN is written to one, the current DMA
transfer is closed when the received PID packet is not MDATA.
Writing a zero to this bit to disable this feature.
• LDNXTCHDESCEN: Load Next Channel Descriptor Enable
1: the channel controller loads the next descriptor after the end of the current transfer, i.e. when the UDDMAnSTATUS.CHEN bit
is reset.
0: no channel register is loaded after the end of the channel transfer.
If the CHEN bit is written to zero, the next descriptor is immediately loaded upon transfer request (endpoint is free for IN
endpoint, or endpoint is full for OUT endpoint).
Table 26-7.
LDNXTCHDES
CEN
CHEN
DMA Channel Control Command Summary
Current Bank
0
0
stop now
0
1
Run and stop at end of buffer
1
0
Load next descriptor now
1
1
Run and link at end of buffer
• CHEN: Channel Enable
Writing this bit to zero will disabled the DMA channel and no transfer will occur upon request. If the LDNXTCHDESCEN bit is
written to zero, the channel is frozen and the channel registers may then be read and/or written reliably as soon as both
UDDMAnSTATUS.CHEN and CHACTIVE bits are zero.
Writing this bit to one will set the UDDMAnSTATUS.CHEN bit and enable DMA channel data transfer. Then any pending request
will start the transfer. This may be used to start or resume any requested transfer.
This bit is cleared when the channel source bus is disabled at end of buffer. If the LDNXTCHDESCEN bit has been cleared by
descriptor loading, the user will have to write to one the corresponding CHEN bit to start the described transfer, if needed.
If a channel request is currently serviced when this bit is zero, the DMA FIFO buffer is drained until it is empty, then the
UDDMAnSTATUS.CHEN bit is cleared.
If the LDNXTCHDESCEN bit is set or after this bit clearing, then the currently loaded descriptor is skipped (no data transfer
occurs) and the next descriptor is immediately loaded.
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26.8.2.20
Device DMA Channel n Status Register
Register Name:
UDDMAnSTATUS, n in [1..7]
Access Type:
Read/Write
Offset:
0x031C + (n - 1) * 0x10
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
18
17
16
CHBYTECNT[15:8]
23
22
21
20
19
CHBYTECNT[7:0]
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
DESCLD
STA
EOCHBUFF
STA
EOTSTA
-
-
CHACTIVE
CHEN
• CHBYTECNT: Channel Byte Count
This field contains the current number of bytes still to be transferred for this buffer.
This field is decremented at each dma access.
This field is reliable (stable) only if the CHEN bit is zero.
• DESCLDSTA: Descriptor Loaded Status
This bit is set when a Descriptor has been loaded from the HSB bus.
This bit is cleared when read by the user.
• EOCHBUFFSTA: End of Channel Buffer Status
This bit is set when the Channel Byte Count counts down to zero.
This bit is automatically cleared when read by software.
• EOTSTA: End of USB Transfer Status
This bit is set when the completion of the usb data transfer has closed the dma transfer. It is valid only if
UDDMAnCONTROL.BUFFCLOSEINEN is one.
This bit is automatically cleared when read by software.
• CHACTIVE: Channel Active
0: the DMA channel is no longer trying to source the packet data.
1: the DMA channel is currently trying to source packet data, i.e. selected as the highest-priority requesting channel. When a
packet transfer cannot be completed due to an EOCHBUFFSTA, this bit stays set during the next channel descriptor load (if any)
and potentially until USB packet transfer completion, if allowed by the new descriptor.
When programming a DMA by descriptor (Load next descriptor now), the CHACTIVE bit is set only once the DMA is running
(the endpoint is free for IN transaction, the endpoint is full for OUT transaction).
• CHEN: Channel Enabled
This bit is set (after one cycle latency) when the L.CHEN is written to one or when the descriptor is loaded.
This bit is cleared when any transfer is ended either due to an elapsed byte count or a USB device initiated transfer end.
0: the DMA channel no longer transfers data, and may load the next descriptor if the UDDMAnCONTROL.LDNXTCHDESCEN
bit is zero.
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1: the DMA channel is currently enabled and transfers data upon request.
If a channel request is currently serviced when the UDDMAnCONTROL.CHEN bit is written to zero, the DMA FIFO buffer is
drained until it is empty, then this status bit is cleared.
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26.8.3
USB Host Registers
26.8.3.1
Host General Control Register
Register Name:
UHCON
Access Type:
Read/Write
Offset:
0x0400
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
RESUME
RESET
SOFE
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
-
SPDCONF
• SPDCONF: Speed Configuration
This field contains the host speed capability.
SPDCONF
Speed
0
0
Normal mode: the host start in full-speed mode and perform a high-speed reset to switch to
the high-speed mode if the downstream peripheral is high-speed capable.
0
1
reserved, do not use this configuration
1
0
reserved, do not use this configuration
1
1
Full-speed: the host remains to full-speed mode whatever is the peripheral speed capability.
• RESUME: Send USB Resume
Writing a one to this bit will generate a USB Resume on the USB bus.
This bit is cleared when the USB Resume has been sent or when a USB reset is requested.
Writing a zero to this bit has no effect.
This bit should be written to one only when the start of frame generation is enable. (SOFE bit is one).
• RESET: Send USB Reset
Writing a one to this bit will generate a USB Reset on the USB bus.
This bit is cleared when the USB Reset has been sent.
It may be useful to write a zero to this bit when a device disconnection is detected (UHINT.DDISCI is one) whereas a USB Reset
is being sent.
• SOFE: Start of Frame Generation Enable
Writing a one to this bit will generate SOF on the USB bus in full speed mode and keep alive in low speed mode.
Writing a zero to this bit will disable the SOF generation and to leave the USB bus in idle state.
This bit is set when a USB reset is requested or an upstream resume interrupt is detected (UHINT.TXRSMI).
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26.8.3.2
Host Global Interrupt Register
Register Name:
UHINT
Access Type:
Read-Only
Offset:
0x0404
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
DMA7INT
DMA6INT
DMA5INT
DMA4INT
DMA3INT
DMA2INT
DMA1INT
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
P7INT
P6INT
P5INT
P4INT
P3INT
P2INT
P1INT
P0INT
7
6
5
4
3
2
1
0
-
HWUPI
HSOFI
RXRSMI
RSMEDI
RSTI
DDISCI
DCONNI
• DMAnINT: DMA Channel n Interrupt
This bit is set when an interrupt is triggered by the DMA channel n. This triggers a USB interrupt if the corresponding
DMAnINTE is one (UHINTE register).
This bit is cleared when the UHDMAnSTATUS interrupt source is cleared.
• PnINT: Pipe n Interrupt
This bit is set when an interrupt is triggered by the endpoint n (UPSTAn). This triggers a USB interrupt if the corresponding pipe
interrupt enable bit is one (UHINTE register).
This bit is cleared when the interrupt source is served.
• HWUPI: Host Wake-Up Interrupt
This bit is set when the host controller is in the suspend mode (SOFE is zero) and an upstream resume from the peripheral is
detected.
This bit is set when the host controller is in the suspend mode (SOFE is zero) and a peripheral disconnection is detected.
This bit is set when the host controller is in the Idle state (USBSTA.VBUSRQ is zero, no VBus is generated), and an OTG SRP
event initiated by the peripheral is detected (USBSTA.SRPI is one).
This interrupt is generated even if the clock is frozen by the FRZCLK bit.
• HSOFI: Host Start of Frame Interrupt
This bit is set when a SOF is issued by the Host controller. This triggers a USB interrupt when HSOFE is one. When using the
host controller in low speed mode, this bit is also set when a keep-alive is sent.
This bit is cleared when the HSOFIC bit is written to one.
• RXRSMI: Upstream Resume Received Interrupt
This bit is set when an Upstream Resume has been received from the Device.
This bit is cleared when the RXRSMIC is written to one.
• RSMEDI: Downstream Resume Sent Interrupt
This bit set when a Downstream Resume has been sent to the Device.
This bit is cleared when the RSMEDIC bit is written to one.
• RSTI: USB Reset Sent Interrupt
This bit is set when a USB Reset has been sent to the device.
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This bit is cleared when the RSTIC bit is written to one.
• DDISCI: Device Disconnection Interrupt
This bit is set when the device has been removed from the USB bus.
This bit is cleared when the DDISCIC bit is written to one.
• DCONNI: Device Connection Interrupt
This bit is set when a new device has been connected to the USB bus.
This bit is cleared when the DCONNIC bit is written to one.
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26.8.3.3
Host Global Interrupt Clear Register
Register Name:
UHINTCLR
Access Type:
Write-Only
Offset:
0x0408
Read Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
HWUPIC
HSOFIC
RXRSMIC
RSMEDIC
RSTIC
DDISCIC
DCONNIC
Writing a one to a bit in this register will clear the corresponding bit in UHINT.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
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26.8.3.4
Host Global Interrupt Set Register
Register Name:
UHINTSET
Access Type:
Write-Only
Offset:
0x040C
Read Value:
0x00000000
31
30
29
28
27
26
25
24
DMA7INTS
DMA6INTS
DMA5INTS
DMA4INTS
DMA3INTS
DMA2INTS
DMA1INTS
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
HWUPIS
HSOFIS
RXRSMIS
RSMEDIS
RSTIS
DDISCIS
DCONNIS
Writing a one to a bit in this register will set the corresponding bit in UHINT, what may be useful for test or debug purposes.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
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26.8.3.5
Host Global Interrupt Enable Register
Register Name:
UHINTE
Access Type:
Read-Only
Offset:
0x0410
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
DMA7INTE
DMA6INTE
DMA5INTE
DMA4INTE
DMA3INTE
DMA2INTE
DMA1INTE
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
P7INTE
P6INTE
P5INTE
P4INTE
P3INTE
P2INTE
P1INTE
P0INTE
7
6
5
4
3
2
1
0
-
HWUPIE
HSOFIE
RXRSMIE
RSMEDIE
RSTIE
DDISCIE
DCONNIE
• DMAnINTE: DMA Channel n Interrupt Enable
This bit is set when the DMAnINTES bit is written to one. This will enable the DMA Channel n Interrupt (DMAnINT).
This bit is cleared when the DMAnINTEC bit is written to one. This will disable the DMA Channel n Interrupt (DMAnINT).
• PnINTE: Pipe n Interrupt Enable
This bit is set when the PnINTES bit is written to one. This will enable the Pipe n Interrupt (PnINT).
This bit is cleared when the PnINTEC bit is written to one. This will disable the Pipe n Interrupt (PnINT).
• HWUPIE: Host Wake-Up Interrupt Enable
This bit is set when the HWUPIES bit is written to one. This will enable the Host Wake-up Interrupt (HWUPI).
This bit is cleared when the HWUPIEC bit is written to one. This will disable the Host Wake-up Interrupt (HWUPI).
• HSOFIE: Host Start of Frame Interrupt Enable
This bit is set when the HSOFIES bit is written to one. This will enable the Host Start of Frame interrupt (HSOFI).
This bit is cleared when the HSOFIEC bit is written to one. This will disable the Host Start of Frame interrupt (HSOFI).
• RXRSMIE: Upstream Resume Received Interrupt Enable
This bit is set when the RXRSMIES bit is written to one. This will enable the Upstream Resume Received interrupt (RXRSMI).
This bit is cleared when the RXRSMIEC bit is written to one. This will disable the Downstream Resume interrupt (RXRSMI).
• RSMEDIE: Downstream Resume Sent Interrupt Enable
This bit is set when the RSMEDIES bit is written to one. This will enable the Downstream Resume interrupt (RSMEDI).
This bit is cleared when the RSMEDIEC bit is written to one. This will disable the Downstream Resume interrupt (RSMEDI).
• RSTIE: USB Reset Sent Interrupt Enable
This bit is set when the RSTIES bit is written to one. This will enable the USB Reset Sent interrupt (RSTI).
This bit is cleared when the RSTIEC bit is written to one. This will disable the USB Reset Sent interrupt (RSTI).
• DDISCIE: Device Disconnection Interrupt Enable
This bit is set when the DDISCIES bit is written to one. This will enable the Device Disconnection interrupt (DDISCI).
This bit is cleared when the DDISCIEC bit is written to one. This will disable the Device Disconnection interrupt (DDISCI).
• DCONNIE: Device Connection Interrupt Enable
This bit is set when the DCONNIES bit is written to one. This will enable the Device Connection interrupt (DCONNI).
This bit is cleared when the DCONNIEC bit is written to one. This will disable the Device Connection interrupt (DCONNI).
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26.8.3.6
Host Global Interrupt Enable Clear Register
Register Name:
UHINTECLR
Access Type:
Write-Only
Offset:
0x0414
Read Value:
0x00000000
31
30
29
28
27
26
25
24
DMA7INTEC
DMA6INTEC
DMA5INTEC
DMA4INTEC
DMA3INTEC
DMA2INTEC
DMA1INTEC
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
P7INTEC
P6INTEC
P5INTEC
P4INTEC
P3INTEC
P2INTEC
P1INTEC
P0INTEC
7
6
5
4
3
2
1
0
-
HWUPIEC
HSOFIEC
RXRSMIEC
RSMEDIEC
RSTIEC
DDISCIEC
DCONNIEC
Writing a one to a bit in this register will clear the corresponding bit in UHINTE.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
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AT32UC3A3/A4
26.8.3.7
Host Global Interrupt Enable Set Register
Register Name:
UHINTESET
Access Type:
Write-Only
Offset:
0x0418
Read Value:
0x00000000
31
30
29
28
27
26
25
24
DMA7INTES
DMA6INTES
DMA5INTES
DMA4INTES
DMA3INTES
DMA2INTES
DMA1INTES
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
P7INTES
P6INTES
P5INTES
P4INTES
P3INTES
P2INTES
P1INTES
P0INTES
7
6
5
4
3
2
1
0
-
HWUPIES
HSOFIES
RXRSMIES
RSMEDIES
RSTIES
DDISCIES
DCONNIES
Writing a one to a bit in this register will set the corresponding bit in UHINT.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
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32072C–AVR32–2010/03
AT32UC3A3/A4
26.8.3.8
Host Frame Number Register
Register Name:
UHFNUM
Access Type:
Read/Write
Offset:
0x0420
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
11
10
9
8
2
1
0
FLENHIGH
15
14
-
-
7
6
13
12
FNUM[10:5]
5
FNUM[4:0]
4
3
MFNUM
• FLENHIGH: Frame Length
In Full speed mode, this field contains the 8 high-order bits of the 16-bit internal frame counter (at 30MHz, counter length is
30000 to ensure a SOF generation every 1 ms).
In High speed mode, this field contains the 8 high-order bits of the 16-bit internal frame counter (at 30MHz, counter length is
3750 to ensure a SOF generation every 125 us).
• FNUM: Frame Number
This field contains the current SOF number.
This field can be written. In this case, the MFNUM field is reset to zero.
• MFNUM: Micro Frame Number
This field contains the current Micro Frame number (can vary from 0 to 7) updated every 125us.
When operating in full-speed mode, this field is tied to zero.
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32072C–AVR32–2010/03
AT32UC3A3/A4
26.8.3.9
USB Host Frame Number Register (UHADDR1)
Register Name:
UHADDR1
Access Type:
Read/Write
Offset:
0x0424
Reset Value:
0x00000000
31
30
29
28
-
23
22
21
20
-
25
24
19
18
17
16
10
9
8
2
1
0
UHADDRP2
14
13
12
-
7
26
UHADDRP3
-
15
27
11
UHADDRP1
6
5
4
3
UHADDRP0
• UHADDRP3: USB Host Address
This field contains the address of the Pipe3 of the USB Device.
This field is cleared when a USB reset is requested.
• UHADDRP2: USB Host Address
This field contains the address of the Pipe2 of the USB Device.
This field is cleared when a USB reset is requested.
• UHADDRP1: USB Host Address
This field contains the address of the Pipe1 of the USB Device.
This field is cleared when a USB reset is requested.
• UHADDRP0: USB Host Address
This field contains the address of the Pipe0 of the USB Device.
This field is cleared when a USB reset is requested.
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32072C–AVR32–2010/03
AT32UC3A3/A4
26.8.3.10
Host Frame Number Register
Register Name:
UHADDR2
Access Type:
Read/Write
Offset:
0x0428
Reset Value:
0x00000000
31
30
29
28
-
23
22
21
20
-
25
24
19
18
17
16
10
9
8
2
1
0
UHADDRP6
14
13
12
-
7
26
UHADDRP7
-
15
27
11
UHADDRP5
6
5
4
3
UHADDRP4
• UHADDRP7: USB Host Address
This field contains the address of the Pipe7 of the USB Device.
This field is cleared when a USB reset is requested.
• UHADDRP6: USB Host Address
This field contains the address of the Pipe6 of the USB Device.
This field is cleared when a USB reset is requested.
• UHADDRP5: USB Host Address
This field contains the address of the Pipe5 of the USB Device.
This field is cleared when a USB reset is requested.
• UHADDRP4: USB Host Address
This field contains the address of the Pipe4 of the USB Device.
This field is cleared when a USB reset is requested.
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AT32UC3A3/A4
26.8.3.11
Pipe Enable/Reset Register
Register Name:
UPRST
Access Type:
Read/Write
Offset:
0x0041C
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
PRST7
PRST6
PRST5
PRST4
PRST3
PRST2
PRST1
PRST0
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
PEN7
PEN6
PEN5
PEN4
PEN3
PEN2
PEN1
PEN0
• PRSTn: Pipe n Reset
Writing a one to this bit will reset the Pipe n FIFO.
This resets the endpoint n registers (UPCFGn, UPSTAn, UPCONn) but not the endpoint configuration (ALLOC, PBK, PSIZE,
PTOKEN, PTYPE, PEPNUM, INTFRQ).
All the endpoint mechanism (FIFO counter, reception, transmission, etc.) is reset apart from the Data Toggle management.
The endpoint configuration remains active and the endpoint is still enabled.
Writing a zero to this bit will complete the reset operation and allow to start using the FIFO.
• PENn: Pipe n Enable
Writing a one to this bit will enable the Pipe n.
Writing a zero to this bit will disable the Pipe n, what forces the Pipe n state to inactive and resets the pipe n registers (UPCFGn,
UPSTAn, UPCONn) but not the pipe configuration (ALLOC, PBK, PSIZE).
734
32072C–AVR32–2010/03
AT32UC3A3/A4
26.8.3.12
Pipe n Configuration Register
Register Name:
UPCFGn, n in [0..7]
Access Type:
Read/Write
Offset:
0x0500 + (n * 0x04)
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
18
17
16
9
8
INTFRQ/BINTERVAL
23
22
21
20
-
-
-
PINGEN
15
14
13
12
-
-
7
6
PTYPE
5
-
4
PSIZE
19
PEPNUM
11
10
-
AUTOSW
3
2
PBK
PTOKEN
1
0
ALLOC
-
• INTFRQ: Pipe Interrupt Request Frequency
This field contains the maximum value in millisecond of the polling period for an Interrupt Pipe.
This value has no effect for a non-Interrupt Pipe.
This field is cleared upon sending a USB reset.
• BINTERVAL: bInterval parameter for the Bulk-Out/Ping transaction
This field contains the Ping/Bulk-out period.
If BINTERVAL>0 and PINGEN=1, one PING token is sent every BINTERVAL micro-frame until it is ACKed by the peripheral.
If BINTERVAL=0 and PINGEN=1, multiple consecutive PING token is sent in the same micro-frame until it is ACKed.
If BINTERVAL>0 and PINGEN=0, one OUT token is sent every BINTERVAL micro-frame until it is ACKed by the peripheral.
If BINTERVAL=0 and PINGEN=0, multiple consecutive OUT token is sent in the same micro-frame until it is ACKed.
This value must be in the range from 0 to 255.
• PINGEN: Ping Enable
This bit is relevant for High-speed Bulk-out transaction only (including the control data stage and the control status stage).
Writing a zero to this bit will disable the ping protocol.
Writing a one to this bit will enable the ping mechanism according to the usb 2.0 standard.
This bit is cleared upon sending a USB reset.
• PEPNUM: Pipe Endpoint Number
This field contains the number of the endpoint targeted by the pipe. This value is from 0 to 15.
This field is cleared upon sending a USB reset.
• PTYPE: Pipe Type
This field contains the pipe type.
PTYPE
0
Pipe Type
0
Control
735
32072C–AVR32–2010/03
AT32UC3A3/A4
PTYPE
Pipe Type
0
1
Isochronous
1
0
Bulk
1
1
Interrupt
This field is cleared upon sending a USB reset.
• AUTOSW: Automatic Switch
This bit is cleared upon sending a USB reset.
1: The automatic bank switching is enabled.
0: The automatic bank switching is disabled.
• PTOKEN: Pipe Token
This field contains the endpoint token.
PTOKEN
Endpoint Direction
00
SETUP
01
IN
10
OUT
11
reserved
• PSIZE: Pipe Size
This field contains the size of each pipe bank.
PSIZE
Endpoint Size
0
0
0
8 bytes
0
0
1
16 bytes
0
1
0
32 bytes
0
1
1
64 bytes
1
0
0
128 bytes
1
0
1
256 bytes
1
1
0
512 bytes
1
1
1
1024 bytes
This field is cleared upon sending a USB reset.
• PBK: Pipe Banks
This field contains the number of banks for the pipe.
PBK
Endpoint Banks
0
0
1 (single-bank pipe)
0
1
2 (double-bank pipe)
1
0
3 (triple-bank pipe)
1
1
Reserved
For control endpoints, a single-bank pipe (0b00) should be selected.
This field is cleared upon sending a USB reset.
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AT32UC3A3/A4
• ALLOC: Pipe Memory Allocate
Writing a one to this bit will allocate the pipe memory.
Writing a zero to this bit will free the pipe memory.
This bit is cleared when a USB Reset is requested.
Refer to the DPRAM Management chapter for more details.
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32072C–AVR32–2010/03
AT32UC3A3/A4
26.8.3.13
Pipe n Status Register
Register Name:
UPSTAn, n in [0..7]
Access Type:
Read-Only
Offset:
0x0530 + (n * 0x04)
Reset Value:
0x00000000
31
30
29
28
-
27
26
25
24
19
18
17
16
-
CFGOK
-
RWALL
11
10
9
8
-
-
PBYCT[10:4]
23
22
21
20
PBYCT[3:0]
15
14
13
CURRBK
12
NBUSYBK
DTSEQ
7
6
5
4
3
2
1
0
SHORT
PACKETI
RXSTALLDI/
CRCERRI
OVERFI
NAKEDI
PERRI
TXSTPI/
UNDERFI
TXOUTI
RXINI
• PBYCT: Pipe Byte Count
This field contains the byte count of the FIFO.
For OUT pipe, incremented after each byte written by the user into the pipe and decremented after each byte sent to the
peripheral.
For IN pipe, incremented after each byte received from the peripheral and decremented after each byte read by the user from
the pipe.
This field may be updated 1 clock cycle after the RWALL bit changes, so the user should not poll this field as an interrupt bit.
• CFGOK: Configuration OK Status
This bit is set/cleared when the UPCFGn.ALLOC bit is set.
This bit is set if the pipe n number of banks (UPCFGn.PBK) and size (UPCFGn.PSIZE) are correct compared to the maximal
allowed number of banks and size for this pipe and to the maximal FIFO size (i.e., the DPRAM size).
If this bit is cleared, the user should rewrite correct values ot the PBK and PSIZE field in the UPCFGn register.
• RWALL: Read/Write Allowed
For OUT pipe, this bit is set when the current bank is not full, i.e., the software can write further data into the FIFO.
For IN pipe, this bit is set when the current bank is not empty, i.e., the software can read further data from the FIFO.
This bit is cleared otherwise.
This bit is also cleared when the RXSTALL or the PERR bit is one.
• CURRBK: Current Bank
For non-control pipe, this field indicates the number of the current bank.
CURRBK
0
Current Bank
0
Bank0
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AT32UC3A3/A4
CURRBK
Current Bank
0
1
Bank1
1
0
Bank2
1
1
Reserved
This field may be updated 1 clock cycle after the RWALL bit changes, so the user shall not poll this field as an interrupt bit.
• NBUSYBK: Number of Busy Banks
This field indicates the number of busy bank.
For OUT pipe, this field indicates the number of busy bank(s), filled by the user, ready for OUT transfer. When all banks are
busy, this triggers an PnINT interrupt if UPCONn.NBUSYBKE is one.
For IN pipe, this field indicates the number of busy bank(s) filled by IN transaction from the Device. When all banks are free, this
triggers an PnINT interrupt if UPCONn.NBUSYBKE is one.
NBUSYBK
Number of busy bank
0
0
All banks are free.
0
1
1 busy bank
1
0
2 busy banks
1
1
reserved
• DTSEQ: Data Toggle Sequence
This field indicates the data PID of the current bank.
DTSEQ
•
•
•
•
•
Data toggle sequence
0
0
Data0
0
1
Data1
1
0
reserved
1
1
reserved
For OUT pipe, this field indicates the data toggle of the next packet that will be sent.
For IN pipe, this field indicates the data toggle of the received packet stored in the current bank.
SHORTPACKETI: Short Packet Interrupt
This bit is set when a short packet is received by the host controller (packet length inferior to the PSIZE programmed field).
This bit is cleared when the SHORTPACKETIC bit is written to one.
RXSTALLDI: Received STALLed Interrupt
This bit is set, for all endpoints but isochronous, when a STALL handshake has been received on the current bank of the pipe.
The Pipe is automatically frozen. This triggers an interrupt if the RXSTALLE bit is one.
This bit is cleared when the RXSTALLDIC bit is written to one.
CRCERRI: CRC Error Interrupt
This bit is set, for isochronous endpoint, when a CRC error occurs on the current bank of the Pipe. This triggers an interrupt if
the TXSTPE bit is one.
This bit is cleared when the CRCERRIC bit is written to one.
OVERFI: Overflow Interrupt
This bit is set when the current pipe has received more data than the maximum length of the current pipe. An interrupt is
triggered if the OVERFIE bit is one.
This bit is cleared when the OVERFIC bit is written to one.
NAKEDI: NAKed Interrupt
This bit is set when a NAK has been received on the current bank of the pipe. This triggers an interrupt if the NAKEDE bit is one.
739
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AT32UC3A3/A4
This bit is cleared when the NAKEDIC bit written to one.
• PERRI: Pipe Error Interrupt
This bit is set when an error occurs on the current bank of the pipe. This triggers an interrupt if the PERRE bit is set. Refers to
the UPERRn register to determine the source of the error.
This bit is cleared when the error source bit is cleared.
• TXSTPI: Transmitted SETUP Interrupt
This bit is set, for Control endpoints, when the current SETUP bank is free and can be filled. This triggers an interrupt if the
TXSTPE bit is one.
This bit is cleared when the TXSTPIC bit is written to one.
• UNDERFI: Underflow Interrupt
This bit is set, for isochronous and Interrupt IN/OUT pipe, when an error flow occurs. This triggers an interrupt if the UNDERFIE
bit is one.
This bit is set, for Isochronous or interrupt OUT pipe, when a transaction underflow occurs in the current pipe. (the pipe can’t
send the OUT data packet in time because the current bank is not ready). A zero-length-packet (ZLP) will be sent instead of.
This bit is set, for Isochronous or interrupt IN pipe, when a transaction flow error occurs in the current pipe. i.e, the current bank
of the pipe is not free whereas a new IN USB packet is received. This packet is not stored in the bank. For Interrupt pipe, the
overflowed packet is ACKed to respect the USB standard.
This bit is cleared when the UNDERFIEC bit is written to one.
• TXOUTI: Transmitted OUT Data Interrupt
This bit is set when the current OUT bank is free and can be filled. This triggers an interrupt if the TXOUTE bit is one.
This bit is cleared when the TXOUTIC bit is written to one.
• RXINI: Received IN Data Interrupt
This bit is set when a new USB message is stored in the current bank of the pipe. This triggers an interrupt if the RXINE bit is
one.
This bit is cleared when the RXINIC bit is written to one.
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AT32UC3A3/A4
26.8.3.14
Pipe n Status Clear Register
Register Name:
UPSTAnCLR, n in [0..7]
Access Type:
Write-Only
Offset:
0x0560 + (n * 0x04)
Read Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
SHORT
PACKETIC
RXSTALLDI
C/
CRCERRIC
OVERFIC
NAKEDIC
-
TXSTPIC/
UNDERFIC
TXOUTIC
RXINIC
Writing a one to a bit in this register will clear the corresponding bit in UPSTAn.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
741
32072C–AVR32–2010/03
AT32UC3A3/A4
26.8.3.15
Pipe n Status Set Register
Register Name:
UPSTAnSET, n in [0..7]
Access Type:
Write-Only
Offset:
0x0590 + (n * 0x04)
Read Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
NBUSYBKS
-
-
-
-
7
6
5
4
3
2
1
0
SHORT
PACKETIS
RXSTALLDIS/
OVERFIS
NAKEDIS
PERRIS
TXSTPIS/
UNDERFIS
TXOUTIS
RXINIS
CRCERRIS
Writing a one to a bit in this register will set the corresponding bit in UPSTAn, what may be useful for test or debug purposes.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
742
32072C–AVR32–2010/03
AT32UC3A3/A4
26.8.3.16
Pipe n Control Register
Register Name:
UPCONn, n in [0..7]
Access Type:
Read-Only
Offset:
0x05C0 + (n * 0x04)
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
RSTDT
PFREEZE
PDISHDMA
15
14
13
12
11
10
9
8
-
FIFOCON
-
NBUSYBKE
-
-
-
-
7
6
5
4
3
2
1
0
SHORT
PACKETIE
RXSTALLDE/
CRCERRE
OVERFIE
NAKEDE
PERRE
TXSTPE/
UNDERFIE
TXOUTE
RXINE
• RSTDT: Reset Data Toggle
This bit is set when the RSTDTS bit is written to one. This will reset the Data Toggle to its initial value for the current Pipe.
This bit is cleared when proceed.
• PFREEZE: Pipe Freeze
This bit is set when the PFREEZES bit is written to one or when the pipe is not configured or when a STALL handshake has
been received on this Pipe or when an error occurs on the Pipe (PERR is one) or when (INRQ+1) In requests have been
processed or when after a Pipe reset (UPRST.PRSTn rising) or a Pipe Enable (UPRST.PEN rising). This will Freeze the Pipe
requests generation.
This bit is cleared when the PFREEZEC bit is written to one. This will enable the Pipe request generation.
• PDISHDMA: Pipe Interrupts Disable HDMA Request Enable
See the UECONn.EPDISHDMA bit description.
• FIFOCON: FIFO Control
For OUT and SETUP Pipe:
This bit is set when the current bank is free, at the same time than TXOUTI or TXSTPI.
This bit is cleared when the FIFOCONC bit is written to one. This will send the FIFO data and switch the bank.
For IN Pipe:
This bit is set when a new IN message is stored in the current bank, at the same time than RXINI.
This bit is cleared when the FIFOCONC bit is written to one. This will free the current bank and switch to the next bank.
• NBUSYBKE: Number of Busy Banks Interrupt Enable
This bit is set when the NBUSYBKES bit is written to one.This will enable the Transmitted IN Data interrupt (NBUSYBKE).
This bit is cleared when the NBUSYBKEC bit is written to one. This will disable the Transmitted IN Data interrupt (NBUSYBKE).
• SHORTPACKETIE: Short Packet Interrupt Enable
This bit is set when the SHORTPACKETES bit is written to one. This will enable the Transmitted IN Data IT (SHORTPACKETIE).
This bit is cleared when the SHORTPACKETEC bit is written to one. This will disable the Transmitted IN Data IT
(SHORTPACKETE).
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• RXSTALLDE: Received STALLed Interrupt Enable
This bit is set when the RXSTALLDES bit is written to one. This will enable the Transmitted IN Data interrupt (RXSTALLDE).
This bit is cleared when the RXSTALLDEC bit is written to one. This will disable the Transmitted IN Data interrupt
(RXSTALLDE).
• CRCERRE: CRC Error Interrupt Enable
This bit is set when the CRCERRES bit is written to one. This will enable the Transmitted IN Data interrupt (CRCERRE).
This bit is cleared when the CRCERREC bit is written to one. This will disable the Transmitted IN Data interrupt (CRCERRE).
• OVERFIE: Overflow Interrupt Enable
This bit is set when the OVERFIES bit is written to one. This will enable the Transmitted IN Data interrupt (OVERFIE).
This bit is cleared when the OVERFIEC bit is written to one. This will disable the Transmitted IN Data interrupt (OVERFIE).
• NAKEDE: NAKed Interrupt Enable
This bit is set when the NAKEDES bit is written to one. This will enable the Transmitted IN Data interrupt (NAKEDE).
This bit is cleared when the NAKEDEC bit is written to one. This will disable the Transmitted IN Data interrupt (NAKEDE).
• PERRE: Pipe Error Interrupt Enable
This bit is set when the PERRES bit is written to one. This will enable the Transmitted IN Data interrupt (PERRE).
This bit is cleared when the PERREC bit is written to one. This will disable the Transmitted IN Data interrupt (PERRE).
• TXSTPE: Transmitted SETUP Interrupt Enable
This bit is set when the TXSTPES bit is written to one. This will enable the Transmitted IN Data interrupt (TXSTPE).
This bit is cleared when the TXSTPEC bit is written to one. This will disable the Transmitted IN Data interrupt (TXSTPE).
• UNDERFIE: Underflow Interrupt Enable
This bit is set when the UNDERFIES bit is written to one. This will enable the Transmitted IN Data interrupt (UNDERFIE).
This bit is cleared when the UNDERFIEC bit is written to one. This will disable the Transmitted IN Data interrupt (UNDERFIE).
• TXOUTE: Transmitted OUT Data Interrupt Enable
This bit is set when the TXOUTES bit is written to one. This will enable the Transmitted IN Data interrupt (TXOUTE).
This bit is cleared when the TXOUTEC bit is written to one. This will disable the Transmitted IN Data interrupt (TXOUTE).
• RXINE: Received IN Data Interrupt Enable
This bit is set when the RXINES bit is written to one. This will enable the Transmitted IN Data interrupt (RXINE).
This bit is cleared when the RXINEC bit is written to one. This will disable the Transmitted IN Data interrupt (RXINE).
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26.8.3.17
Pipe n Control Clear Register
Register Name:
UPCONnCLR, n in [0..7]
Access Type:
Write-Only
Offset:
0x0620 + (n * 0x04)
Read Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
PFREEZEC
PDISHDMAC
15
14
13
12
11
10
9
8
-
FIFOCONC
-
NBUSYBKEC
-
-
-
-
7
6
5
4
3
2
1
0
SHORT
PACKETIEC
RXSTALLDEC/
OVERFIEC
NAKEDEC
PERREC
TXSTPEC/
UNDERFIEC
TXOUTEC
RXINEC
CRCERREC
Writing a one to a bit in this register will clear the corresponding bit in UPCONn.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
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26.8.3.18
Pipe n Control Set Register
Register Name:
UPCONnSET, n in [0..7]
Access Type:
Write-Only
Offset:
0x05F0 + (n * 0x04)
Read Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
RSTDTS
PFREEZES
PDISHDMAS
15
14
13
12
11
10
9
8
-
-
-
NBUSYBKES
-
-
-
-
7
6
5
4
3
2
1
0
SHORT
PACKETIES
RXSTALLDES/
OVERFIES
NAKEDES
PERRES
TXSTPES/
UNDERFIES
TXOUTES
RXINES
CRCERRES
Writing a one to a bit in this register will set the corresponding bit in UPCONn.
Writing a zero to a bit in this register has no effect.
This bit always reads as zero.
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26.8.3.19
Pipe n IN Request Register
Register Name:
UPINRQn, n in [0..7]
Access Type:
Read/Write
Offset:
0x0650 + (n * 0x04)
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
INMODE
7
6
5
4
3
2
1
0
INRQ
• INMODE: IN Request Mode
Writing a one to this bit will allow the USBB to perform infinite IN requests when the Pipe is not frozen.
Writing a zero to this bit will perform a pre-defined number of IN requests. This number is the INRQ field.
• INRQ: IN Request Number before Freeze
This field contains the number of IN transactions before the USBB freezes the pipe. The USBB will perform (INRQ+1) IN
requests before to freeze the Pipe. This counter is automatically decreased by 1 each time a IN request has been successfully
performed.
This register has no effect when the INMODE bit is one (infinite IN requests generation till the pipe is not frozen).
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26.8.3.20
Pipe n Error Register
Register Name:
UPERRn, n in [0..7]
Access Type:
Read/Write
Offset:
0x0680 + (n * 0x04)
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
-
-
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
CRC16
TIMEOUT
PID
DATAPID
DATATGL
-
COUNTER
• COUNTER: Error Counter
This field is incremented each time an error occurs (CRC16, TIMEOUT, PID, DATAPID or DATATGL).
This field is cleared when receiving a good usb packet without any error.
When this field reaches 3 (i.e., 3 consecutive errors), this pipe is automatically frozen (UPCONn.PFREEZE is set).
Writing 0b00 to this field will clear the counter.
• CRC16: CRC16 Error
This bit is set when a CRC16 error has been detected.
Writing a zero to this bit will clear the bit.
Writing a one to this bit has no effect.
• TIMEOUT: Time-Out Error
This bit is set when a Time-Out error has been detected.
Writing a zero to this bit will clear the bit.
Writing a one to this bit has no effect.
• PID: PID Error
This bit is set when a PID error has been detected.
Writing a zero to this bit will clear the bit.
Writing a one to this bit has no effect.
• DATAPID: Data PID Error
This bit is set when a Data PID error has been detected.
Writing a zero to this bit will clear the bit.
Writing a one to this bit has no effect.
• DATATGL: Data Toggle Error
This bit is set when a Data Toggle error has been detected.
Writing a zero to this bit will clear the bit.
Writing a one to this bit has no effect.
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26.8.3.21
Host DMA Channel n Next Descriptor Address Register
Register Name:
UHDMAnNEXTDESC, n in [1..7]
Access Type:
Read/Write
Offset:
0x0710 + (n - 1) * 0x10
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
18
17
16
10
9
8
3
2
1
0
-
-
-
-
NXTDESCADDR[31:24]
23
22
21
20
19
NXTDESCADDR[23:16]
15
14
13
12
11
NXTDESCADDR[15:8]
7
6
5
NXTDESCADDR[7:4]
4
Same as Section 26.8.2.17.
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26.8.3.22
Host DMA Channel n HSB Address Register
Register Name:
UHDMAnADDR, n in [1..7]
Access Type:
Read/Write
Offset:
0x0714 + (n - 1) * 0x10
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
18
17
16
10
9
8
2
1
0
HSBADDR[31:24]
23
22
21
20
19
HSBADDR[23:16]
15
14
13
12
11
HSBADDR[15:8]
7
6
5
4
3
HSBADDR[7:0]
Same as Section 26.8.2.18.
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26.8.3.23
USB Host DMA Channel n Control Register
Register Name:
UHDMAnCONTROL, n in [1..7]
Access Type:
Read/Write
Offset:
0x0718 + (n - 1) * 0x10
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
18
17
16
CHBYTELENGTH[15:8]
23
22
21
20
19
CHBYTELENGTH[7:0]
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
BURSTLOC
KEN
DESCLD
IRQEN
EOBUFF
IRQEN
EOTIRQEN
DMAENDEN
BUFFCLOSE
INEN
LDNXTCHD
ESCEN
CHEN
Same as Section 26.8.2.19.
(just replace the IN endpoint term by OUT endpoint, and vice-versa)
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26.8.3.24
USB Host DMA Channel n Status Register
Register Name:
UHDMAnSTATUS, n in [1..7]
Access Type:
Read/Write
Offset:
0x071C + (n - 1) * 0x10
Reset Value:
0x00000000
31
30
29
28
27
26
25
24
18
17
16
CHBYTECNT[15:8]
23
22
21
20
19
CHBYTECNT[7:0]
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
DESCLD
STA
EOCHBUFFS
TA
EOTSTA
-
-
CHACTIVE
CHEN
Same as Section 26.8.2.20.
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26.8.4
USB Pipe/Endpoint n FIFO Data Register (USBFIFOnDATA)
The application has access to the physical DPRAM reserved for the Endpoint/Pipe through a
64KB logical address space. The application can access a 64KB buffer linearly or fixedly as the
DPRAM address increment is fully handled by hardware. Byte, half-word and word access are
supported. Data should be access in a big-endian way.
Disabling the USBB (by writing a zero to the USBE bit) does not reset the DPRAM.
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26.9
Module Configuration
The specific configuration for the USBB instance is listed in the following tables. The module bus
clocks listed here are connected to the system bus clocks. Please refer to the Power Manager
chapter for details.
Table 26-8.
Module Clock Name
Module name
Clock name
Clock name
USBB
CLK_USBB_HSB
CLK_USBB_PB
Table 26-9.
Register Reset Values
Register
Reset Value
UVERS
0x00000320
UFEATURES
to be defined
UADDRSIZE
to be defined
UNAME1
to be defined
UNAME2
to be defined
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27. Timer/Counter (TC)
Rev: 2.2.3.1
27.1
Features
• Three 16-bit Timer Counter channels
• A wide range of functions including:
– Frequency measurement
– Event counting
– Interval measurement
– Pulse generation
– Delay timing
– Pulse width modulation
– Up/down capabilities
• Each channel is user-configurable and contains:
– Three external clock inputs
– Five internal clock inputs
– Two multi-purpose input/output signals
• Internal interrupt signal
• Two global registers that act on all three TC channels
27.2
Overview
The Timer Counter (TC) includes three identical 16-bit Timer Counter channels.
Each channel can be independently programmed to perform a wide range of functions including
frequency measurement, event counting, interval measurement, pulse generation, delay timing,
and pulse width modulation.
Each channel has three external clock inputs, five internal clock inputs, and two multi-purpose
input/output signals which can be configured by the user. Each channel drives an internal interrupt signal which can be programmed to generate processor interrupts.
The TC block has two global registers which act upon all three TC channels.
The Block Control Register (BCR) allows the three channels to be started simultaneously with
the same instruction.
The Block Mode Register (BMR) defines the external clock inputs for each channel, allowing
them to be chained.
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27.3
Block Diagram
Figure 27-1. TC Block Diagram
I/O
Contr oller
TIMER_CLOCK1
TCLK0
TIMER_CLOCK2
TIOA1
TIMER_CLOCK4
XC0
TIOA2
TIMER_CLOCK3
TCLK1
XC1
TCLK2
XC2
TIMER_CLOCK5
Timer/Counter
Channel 0
TIOA
TIOB
A0
TIOA0
B0
TIOB0
TC0XC0S
SYNC
CLK0
CLK1
CLK2
INT0
TCLK0
XC0
TCLK1
TIOA0
XC1
TIOA2
XC2
TCLK2
Timer/Counter
Channel 1
XC0
TCLK1
XC1
TCLK2
XC2
TIOA0
TIOA1
TC2XC2S
TIOB
A1
TIOA1
B1
TIOB1
SYNC
TC1XC1S
TCLK0
TIOA
Timer/Counter
Channel 2
INT1
TIOA
TIOB
SYNC
A2
TIOA2
B2
TIOB2
INT2
Timer Count er
Interrupt
Controller
27.4
I/O Lines Description
Table 27-1.
27.5
I/O Lines Description
Pin Name
Description
Type
CLK0-CLK2
External Clock Input
Input
A0-A2
I/O Line A
Input/Output
B0-B2
I/O Line B
Input/Output
Product Dependencies
In order to use this module, other parts of the system must be configured correctly, as described
below.
27.5.1
I/O Lines
The pins used for interfacing the compliant external devices may be multiplexed with I/O lines.
The user must first program the I/O Controller to assign the TC pins to their peripheral functions.
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27.5.2
Power Management
If the CPU enters a sleep mode that disables clocks used by the TC, the TC will stop functioning
and resume operation after the system wakes up from sleep mode.
27.5.3
Clocks
The clock for the TC bus interface (CLK_TC) is generated by the Power Manager. This clock is
enabled at reset, and can be disabled in the Power Manager. It is recommended to disable the
TC before disabling the clock, to avoid freezing the TC in an undefined state.
27.5.4
Interrupts
The TC interrupt request line is connected to the interrupt controller. Using the TC interrupt
requires the interrupt controller to be programmed first.
27.5.5
27.6
Debug Operation
The Timer Counter clocks are frozen during debug operation, unless the OCD system keeps
peripherals running in debug operation.
Functional Description
27.6.1
27.6.1.1
TC Description
The three channels of the Timer Counter are independent and identical in operation. The registers for channel programming are listed in Figure 27-3 on page 772.
Channel I/O Signals
As described in Figure 27-1 on page 756, each Channel has the following I/O signals.
Table 27-2.
Channel I/O Signals Description
Block/Channel
Signal Name
XC0, XC1, XC2
Channel Signal
External Clock Inputs
TIOA
Capture mode: Timer Counter Input
Waveform mode: Timer Counter Output
TIOB
Capture mode: Timer Counter Input
Waveform mode: Timer Counter Input/Output
INT
SYNC
27.6.1.2
Description
Interrupt Signal Output
Synchronization Input Signal
16-bit counter
Each channel is organized around a 16-bit counter. The value of the counter is incremented at
each positive edge of the selected clock. When the counter has reached the value 0xFFFF and
passes to 0x0000, an overflow occurs and the Counter Overflow Status bit in the Channel n Status Register (SRn.COVFS) is set.
The current value of the counter is accessible in real time by reading the Channel n Counter
Value Register (CVn). The counter can be reset by a trigger. In this case, the counter value
passes to 0x0000 on the next valid edge of the selected clock.
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27.6.1.3
Clock selection
At block level, input clock signals of each channel can either be connected to the external inputs
TCLK0, TCLK1 or TCLK2, or be connected to the configurable I/O signals A0, A1 or A2 for
chaining by writing to the BMR register. See Figure 27-2 on page 758.
Each channel can independently select an internal or external clock source for its counter:
• Internal clock signals: TIMER_CLOCK1, TIMER_CLOCK2, TIMER_CLOCK3,
TIMER_CLOCK4, TIMER_CLOCK5. See the Module Configuration Chapter for details about
the connection of these clock sources.
• External clock signals: XC0, XC1 or XC2. See the Module Configuration Chapter for details
about the connection of these clock sources.
This selection is made by the Clock Selection field in the Channel n Mode Register
(CMRn.TCCLKS).
The selected clock can be inverted with the Clock Invert bit in CMRn (CMRn.CLKI). This allows
counting on the opposite edges of the clock.
The burst function allows the clock to be validated when an external signal is high. The Burst
Signal Selection field in the CMRn register (CMRn.BURST) defines this signal.
Note:
In all cases, if an external clock is used, the duration of each of its levels must be longer than the
CLK_TC period. The external clock frequency must be at least 2.5 times lower than the CLK_TC.
Figure 27-2. Clock Selection
TCCLKS
TIMER_CLOCK1
TIMER_CLOCK2
CLKI
TIMER_CLOCK3
TIMER_CLOCK4
TIMER_CLOCK5
Selected
Clock
XC0
XC1
XC2
BURST
1
27.6.1.4
Clock control
The clock of each counter can be controlled in two different ways: it can be enabled/disabled
and started/stopped. See Figure 27-3 on page 759.
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• The clock can be enabled or disabled by the user by writing to the Counter Clock
Enable/Disable Command bits in the Channel n Clock Control Register (CCRn.CLKEN and
CCRn.CLKDIS). In Capture mode it can be disabled by an RB load event if the Counter Clock
Disable with RB Loading bit in CMRn is written to one (CMRn.LDBDIS). In Waveform mode,
it can be disabled by an RC Compare event if the Counter Clock Disable with RC Compare
bit in CMRn is written to one (CMRn.CPCDIS). When disabled, the start or the stop actions
have no effect: only a CLKEN command in CCRn can re-enable the clock. When the clock is
enabled, the Clock Enabling Status bit is set in SRn (SRn.CLKSTA).
• The clock can also be started or stopped: a trigger (software, synchro, external or compare)
always starts the clock. In Capture mode the clock can be stopped by an RB load event if the
Counter Clock Stopped with RB Loading bit in CMRn is written to one (CMRn.LDBSTOP). In
Waveform mode it can be stopped by an RC compare event if the Counter Clock Stopped
with RC Compare bit in CMRn is written to one (CMRn.CPCSTOP). The start and the stop
commands have effect only if the clock is enabled.
Figure 27-3. Clock Control
Selected
Clock
Trigger
CLKSTA
Q
Q
S
CLKEN
CLKDIS
S
R
R
Counter
Clock
27.6.1.5
Stop
Event
Disable
Event
TC operating modes
Each channel can independently operate in two different modes:
• Capture mode provides measurement on signals.
• Waveform mode provides wave generation.
The TC operating mode selection is done by writing to the Wave bit in the CCRn register
(CCRn.WAVE).
In Capture mode, TIOA and TIOB are configured as inputs.
In Waveform mode, TIOA is always configured to be an output and TIOB is an output if it is not
selected to be the external trigger.
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27.6.1.6
Trigger
A trigger resets the counter and starts the counter clock. Three types of triggers are common to
both modes, and a fourth external trigger is available to each mode.
The following triggers are common to both modes:
• Software Trigger: each channel has a software trigger, available by writing a one to the
Software Trigger Command bit in CCRn (CCRn.SWTRG).
• SYNC: each channel has a synchronization signal SYNC. When asserted, this signal has the
same effect as a software trigger. The SYNC signals of all channels are asserted
simultaneously by writing a one to the Synchro Command bit in the BCR register
(BCR.SYNC).
• Compare RC Trigger: RC is implemented in each channel and can provide a trigger when the
counter value matches the RC value if the RC Compare Trigger Enable bit in CMRn
(CMRn.CPCTRG) is written to one.
The channel can also be configured to have an external trigger. In Capture mode, the external
trigger signal can be selected between TIOA and TIOB. In Waveform mode, an external event
can be programmed to be one of the following signals: TIOB, XC0, XC1, or XC2. This external
event can then be programmed to perform a trigger by writing a one to the External Event Trigger Enable bit in CMRn (CMRn.ENETRG).
If an external trigger is used, the duration of the pulses must be longer than the CLK_TC period
in order to be detected.
Regardless of the trigger used, it will be taken into account at the following active edge of the
selected clock. This means that the counter value can be read differently from zero just after a
trigger, especially when a low frequency signal is selected as the clock.
27.6.2
Capture Operating Mode
This mode is entered by writing a zero to the CMRn.WAVE bit.
Capture mode allows the TC channel to perform measurements such as pulse timing, frequency, period, duty cycle and phase on TIOA and TIOB signals which are considered as
inputs.
Figure 27-4 on page 762 shows the configuration of the TC channel when programmed in Capture mode.
27.6.2.1
Capture registers A and B
Registers A and B (RA and RB) are used as capture registers. This means that they can be
loaded with the counter value when a programmable event occurs on the signal TIOA.
The RA Loading Selection field in CMRn (CMRn.LDRA) defines the TIOA edge for the loading of
the RA register, and the RB Loading Selection field in CMRn (CMRn.LDRB) defines the TIOA
edge for the loading of the RB register.
RA is loaded only if it has not been loaded since the last trigger or if RB has been loaded since
the last loading of RA.
RB is loaded only if RA has been loaded since the last trigger or the last loading of RB.
Loading RA or RB before the read of the last value loaded sets the Load Overrun Status bit in
SRn (SRn.LOVRS). In this case, the old value is overwritten.
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27.6.2.2
Trigger conditions
In addition to the SYNC signal, the software trigger and the RC compare trigger, an external trigger can be defined.
The TIOA or TIOB External Trigger Selection bit in CMRn (CMRn.ABETRG) selects TIOA or
TIOB input signal as an external trigger. The External Trigger Edge Selection bit in CMRn
(CMRn.ETREDG) defines the edge (rising, falling or both) detected to generate an external trigger. If CMRn.ETRGEDG is zero (none), the external trigger is disabled.
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TIOA
TIOB
SYNC
MTIOA
MTIOB
TIMER_CLOCK2
TIMER_CLOCK3
TIMER_CLOCK4
TIMER_CLOCK5
XC0
XC1
XC2
TIMER_CLOCK1
1
Edge
Detector
ETRGEDG
SWTRG
CLKI
Edge
Detector
LDRA
CLK
Trig
S
R
OVF
If RA is Loaded
CPCTRG
16-bit
Counter
RESET
Q
LDBSTOP
R
S
CLKEN
Edge
Detector
LDRB
Capture
Register A
Q
CLKSTA
LDBDIS
Capture
Register B
CLKDIS
SR
Timer/Counter Channel
If RA is not Loaded
or RB is Loaded
ABETRG
BURST
TCCLKS
Compare RC =
Register C
COVFS
LDRBS
INT
AT32UC3A3/A4
Figure 27-4. Capture Mode
LOVRS
CPCS
LDRAS
ETRGS
IMR
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27.6.3
Waveform Operating Mode
Waveform operating mode is entered by writing a one to the CMRn.WAVE bit.
In Waveform operating mode the TC channel generates one or two PWM signals with the same
frequency and independently programmable duty cycles, or generates different types of oneshot or repetitive pulses.
In this mode, TIOA is configured as an output and TIOB is defined as an output if it is not used
as an external event.
Figure 27-5 on page 764 shows the configuration of the TC channel when programmed in
Waveform operating mode.
27.6.3.1
Waveform selection
Depending on the Waveform Selection field in CMRn (CMRn.WAVSEL), the behavior of CVn
varies.
With any selection, RA, RB and RC can all be used as compare registers.
RA Compare is used to control the TIOA output, RB Compare is used to control the TIOB output
(if correctly configured) and RC Compare is used to control TIOA and/or TIOB outputs.
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TIOB
SYNC
XC2
XC1
TIMER_CLOCK5
XC0
TIMER_CLOCK4
TIMER_CLOCK3
TIMER_CLOCK2
TIMER_CLOCK1
1
Edge
Detector
EEVTEDG
SWTRG
ENETRG
Trig
CLK
R
S
Register A
Q
CLKSTA
Compare RA =
OVF
WAVSEL
RESET
16-bit
Counter
WAVSEL
Q
SR
Timer/Counter Channel
EEVT
BURST
CLKI
Compare RC =
Compare RB =
CPCSTOP
CPCDIS
Register C
CLKDIS
Register B
R
S
CLKEN
CPAS
INT
BSWTRG
BEEVT
BCPB
BCPC
ASWTRG
AEEVT
ACPA
ACPC
O utput Contr oller
O utput Cont r oller
TCCLKS
TIOB
MTIOB
TIOA
MTIOA
AT32UC3A3/A4
Figure 27-5. Waveform Mode
CPCS
CPBS
COVFS
ETRGS
IMR
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AT32UC3A3/A4
27.6.3.2
WAVSEL = 0
When CMRn.WAVSEL is zero, the value of CVn is incremented from 0 to 0xFFFF. Once
0xFFFF has been reached, the value of CVn is reset. Incrementation of CVn starts again and
the cycle continues. See Figure 27-6 on page 765.
An external event trigger or a software trigger can reset the value of CVn. It is important to note
that the trigger may occur at any time. See Figure 27-7 on page 766.
RC Compare cannot be programmed to generate a trigger in this configuration. At the same
time, RC Compare can stop the counter clock (CMRn.CPCSTOP = 1) and/or disable the counter
clock (CMRn.CPCDIS = 1).
Figure 27-6. WAVSEL= 0 Without Trigger
Counter Value
Counter cleared by compare match with
0xFFFF
0xFFFF
RC
RB
RA
Waveform Examples
Time
TIOB
TIOA
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Figure 27-7. WAVSEL= 0 With Trigger
Counter Value
Counter cleared by compare match with 0xFFFF
0xFFFF
RC
Counter cleared by trigger
RB
RA
Waveform Examples
Time
TIOB
TIOA
27.6.3.3
WAVSEL = 2
When CMRn.WAVSEL is two, the value of CVn is incremented from zero to the value of RC,
then automatically reset on a RC Compare. Once the value of CVn has been reset, it is then
incremented and so on. See Figure 27-8 on page 767.
It is important to note that CVn can be reset at any time by an external event or a software trigger if both are programmed correctly. See Figure 27-9 on page 767.
In addition, RC Compare can stop the counter clock (CMRn.CPCSTOP) and/or disable the
counter clock (CMRn.CPCDIS = 1).
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Figure 27-8. WAVSEL = 2 Without Trigger
Counter Value
0xFFFF
Counter cleared by compare match
with RC
RC
RB
RA
Waveform Examples
Time
TIOB
TIOA
Figure 27-9. WAVSEL = 2 With Trigger
Counter Value
0xFFFF
Counter cleared by compare match with RC
Counter cleared by trigger
RC
RB
RA
Waveform Examples
Time
TIOB
TIOA
27.6.3.4
WAVSEL = 1
When CMRn.WAVSEL is one, the value of CVn is incremented from 0 to 0xFFFF. Once 0xFFFF
is reached, the value of CVn is decremented to 0, then re-incremented to 0xFFFF and so on.
See Figure 27-10 on page 768.
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A trigger such as an external event or a software trigger can modify CVn at any time. If a trigger
occurs while CVn is incrementing, CVn then decrements. If a trigger is received while CVn is
decrementing, CVn then increments. See Figure 27-11 on page 768.
RC Compare cannot be programmed to generate a trigger in this configuration.
At the same time, RC Compare can stop the counter clock (CMRn.CPCSTOP = 1) and/or disable the counter clock (CMRn.CPCDIS = 1).
Figure 27-10. WAVSEL = 1 Without Trigger
Counter Value
Counter decremented by compare match
with 0xFFFF
0xFFFF
RC
RB
RA
Time
Waveform Examples
TIOB
TIOA
Figure 27-11. WAVSEL = 1 With Trigger
Counter Value
Counter decremented by compare match with 0xFFFF
0xFFFF
Counter decremented by trigger
RC
RB
Counter incremented by trigger
RA
Waveform Examples
Time
TIOB
TIOA
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27.6.3.5
WAVSEL = 3
When CMRn.WAVSEL is three, the value of CVn is incremented from zero to RC. Once RC is
reached, the value of CVn is decremented to zero, then re-incremented to RC and so on. See
Figure 27-12 on page 769.
A trigger such as an external event or a software trigger can modify CVn at any time. If a trigger
occurs while CVn is incrementing, CVn then decrements. If a trigger is received while CVn is
decrementing, CVn then increments. See Figure 27-13 on page 770.
RC Compare can stop the counter clock (CMRn.CPCSTOP = 1) and/or disable the counter clock
(CMRn.CPCDIS = 1).
Figure 27-12. WAVSEL = 3 Without Trigger
Counter Value
0xFFFF
Counter cleared by compare match with RC
RC
RB
RA
Waveform Examples
Time
TIOB
TIOA
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AT32UC3A3/A4
Figure 27-13. WAVSEL = 3 With Trigger
Counter Value
0xFFFF
Counter decremented by compare match
with RC
RC
Counter decremented by trigger
RB
Counter incremented by trigger
RA
Waveform Examples
TIOB
Time
TIOA
27.6.3.6
External event/trigger conditions
An external event can be programmed to be detected on one of the clock sources (XC0, XC1,
XC2) or TIOB. The external event selected can then be used as a trigger.
The External Event Selection field in CMRn (CMRn.EEVT) selects the external trigger. The
External Event Edge Selection field in CMRn (CMRn.EEVTEDG) defines the trigger edge for
each of the possible external triggers (rising, falling or both). If CMRn.EEVTEDG is written to
zero, no external event is defined.
If TIOB is defined as an external event signal (CMRn.EEVT = 0), TIOB is no longer used as an
output and the compare register B is not used to generate waveforms and subsequently no
IRQs. In this case the TC channel can only generate a waveform on TIOA.
When an external event is defined, it can be used as a trigger by writing a one to the
CMRn.ENETRG bit.
As in Capture mode, the SYNC signal and the software trigger are also available as triggers. RC
Compare can also be used as a trigger depending on the CMRn.WAVSEL field.
27.6.3.7
Output controller
The output controller defines the output level changes on TIOA and TIOB following an event.
TIOB control is used only if TIOB is defined as output (not as an external event).
The following events control TIOA and TIOB:
• software trigger
• external event
• RC compare
RA compare controls TIOA and RB compare controls TIOB. Each of these events can be programmed to set, clear or toggle the output as defined in the following fields in CMRn:
• RC Compare Effect on TIOB (CMRn.BCPC)
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• RB Compare Effect on TIOB (CMRn.BCPB)
• RC Compare Effect on TIOA (CMRn.ACPC)
• RA Compare Effect on TIOA (CMRn.ACPA)
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27.7
User Interface
Table 27-3.
TC Register Memory Map
Offset
Register
Register Name
Access
Reset
0x00
Channel 0 Control Register
CCR0
Write-only
0x00000000
0x04
Channel 0 Mode Register
CMR0
Read/Write
0x00000000
0x10
Channel 0 Counter Value
CV0
Read-only
0x00000000
0x14
Channel 0 Register A
RA0
Read/Write(1)
0x00000000
0x18
Channel 0 Register B
RB0
Read/Write(1)
0x00000000
0x1C
Channel 0 Register C
RC0
Read/Write
0x00000000
0x20
Channel 0 Status Register
SR0
Read-only
00x00000000
0x24
Interrupt Enable Register
IER0
Write-only
0x00000000
0x28
Channel 0 Interrupt Disable Register
IDR0
Write-only
0x00000000
0x2C
Channel 0 Interrupt Mask Register
IMR0
Read-only
0x00000000
0x40
Channel 1 Control Register
CCR1
Write-only
0x00000000
0x44
Channel 1 Mode Register
CMR1
Read/Write
0x00000000
0x50
Channel 1 Counter Value
CV1
Read-only
0x00000000
0x54
Channel 1 Register A
RA1
(1)
0x00000000
(1)
0x00000000
Read/Write
0x58
Channel 1 Register B
RB1
0x5C
Channel 1 Register C
RC1
Read/Write
0x00000000
0x60
Channel 1 Status Register
SR1
Read-only
0x00000000
0x64
Channel 1 Interrupt Enable Register
IER1
Write-only
0x00000000
0x68
Channel 1 Interrupt Disable Register
IDR1
Write-only
0x00000000
0x6C
Channel 1 Interrupt Mask Register
IMR1
Read-only
0x00000000
0x80
Channel 2 Control Register
CCR2
Write-only
0x00000000
0x84
Channel 2 Mode Register
CMR2
Read/Write
0x00000000
0x90
Channel 2 Counter Value
CV2
Read-only
0x00000000
0x94
Channel 2 Register A
RA2
Read/Write(1)
0x00000000
0x98
Channel 2 Register B
RB2
Read/Write(1)
0x00000000
0x9C
Channel 2 Register C
RC2
Read/Write
0x00000000
0xA0
Channel 2 Status Register
SR2
Read-only
0x00000000
0xA4
Channel 2 Interrupt Enable Register
IER2
Write-only
0x00000000
0xA8
Channel 2 Interrupt Disable Register
IDR2
Write-only
0x00000000
0xAC
Channel 2 Interrupt Mask Register
IMR2
Read-only
0x00000000
0xC0
Block Control Register
BCR
Write-only
0x00000000
0xC4
Block Mode Register
BMR
Read/Write
0x00000000
Notes:
Read/Write
1. Read-only if CMRn.WAVE is zero
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27.7.1
Name:
Channel Control Register
CCR
Access Type: