View detail for

Features
• Incorporates the ARM920T™ ARM® Thumb® Processor
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200 MIPS at 180 MHz, Memory Management Unit
16-KByte Data Cache, 16-KByte Instruction Cache, Write Buffer
In-circuit Emulator including Debug Communication Channel
Mid-level Implementation Embedded Trace Macrocell™ (256-ball BGA Package
only)
Low Power: On VDDCORE 24.4 mA in Normal Mode, 520 µA in Standby Mode
Additional Embedded Memories
– 16K Bytes of SRAM and 128K Bytes of ROM
External Bus Interface (EBI)
– Supports SDRAM, Static Memory, Burst Flash, Glueless Connection to
CompactFlash® and NAND Flash/SmartMedia®
System Peripherals for Enhanced Performance:
– Enhanced Clock Generator and Power Management Controller
– Two On-chip Oscillators with Two PLLs
– Very Slow Clock Operating Mode and Software Power Optimization Capabilities
– Four Programmable External Clock Signals
– System Timer Including Periodic Interrupt, Watchdog and Second Counter
– Real-time Clock with Alarm Interrupt
– Debug Unit, Two-wire UART and Support for Debug Communication Channel
– Advanced Interrupt Controller with 8-level Priority, Individually Maskable Vectored
Interrupt Sources, Spurious Interrupt Protected
– Seven External Interrupt Sources and One Fast Interrupt Source
– Four 32-bit PIO Controllers with Up to 122 Programmable I/O Lines, Input Change
Interrupt and Open-drain Capability on Each Line
– 20-channel Peripheral DMA Controller (PDC)
Ethernet MAC 10/100 Base-T
– Media Independent Interface (MII) or Reduced Media Independent Interface (RMII)
– Integrated 28-byte FIFOs and Dedicated DMA Channels for Receive and Transmit
USB 2.0 Full Speed (12 Mbits per second) Host Double Port
– Dual On-chip Transceivers (Single Port Only on 208-lead PQFP Package)
– Integrated FIFOs and Dedicated DMA Channels
USB 2.0 Full Speed (12 Mbits per second) Device Port
– On-chip Transceiver, 2-Kbyte Configurable Integrated FIFOs
Multimedia Card Interface (MCI)
– Automatic Protocol Control and Fast Automatic Data Transfers
– MMC and SD Memory Card-compliant, Supports Up to Two SD Memory Cards
Three Synchronous Serial Controllers (SSC)
– Independent Clock and Frame Sync Signals for Each Receiver and Transmitter
– I2S Analog Interface Support, Time Division Multiplex Support
– High-speed Continuous Data Stream Capabilities with 32-bit Data Transfer
Four Universal Synchronous/Asynchronous Receiver/Transmitters (USART)
– Support for ISO7816 T0/T1 Smart Card
– Hardware Handshaking
– RS485 Support, IrDA® Up To 115 Kbps
– Full Modem Control Lines on USART1
Master/Slave Serial Peripheral Interface (SPI)
– 8- to 16-bit Programmable Data Length, 4 External Peripheral Chip Selects
ARM920T-based
Microcontroller
AT91RM9200
Rev. 1768I-ATARM–09-Jul-09
• Two 3-channel, 16-bit Timer/Counters (TC)
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– Three External Clock Inputs, Two Multi-purpose I/O Pins per Channel
– Double PWM Generation, Capture/Waveform Mode, Up/Down Capability
Two-wire Interface (TWI)
– Master Mode Support, All 2-wire Atmel EEPROMs Supported
IEEE® 1149.1 JTAG Boundary Scan on All Digital Pins
Power Supplies
– 1.65V to 1.95V for VDDCORE, VDDOSC and VDDPLL
– 3.0V to 3.6V for VDDIOP (Peripheral I/Os) and for VDDIOM (Memory I/Os)
Available in a 208-pin Green PQFP or 256-ball RoHS-compliant BGA Package
1. Description
The AT91RM9200 is a complete system-on-chip built around the ARM920T ARM Thumb processor. It incorporates a rich set of system and application peripherals and standard interfaces
in order to provide a single-chip solution for a wide range of compute-intensive applications that
require maximum functionality at minimum power consumption at lowest cost.
The AT91RM9200 incorporates a high-speed on-chip SRAM workspace, and a low-latency
External Bus Interface (EBI) for seamless connection to whatever configuration of off-chip memories and memory-mapped peripherals is required by the application. The EBI incorporates
controllers for synchronous DRAM (SDRAM), Burst Flash and Static memories and features
specific circuitry facilitating the interface for NAND Flash/SmartMedia and Compact Flash.
The Advanced Interrupt Controller (AIC) enhances the interrupt handling performance of the
ARM920T processor by providing multiple vectored, prioritized interrupt sources and reducing
the time taken to transfer to an interrupt handler.
The Peripheral DMA Controller (PDC) provides DMA channels for all the serial peripherals,
enabling them to transfer data to or from on- and off-chip memories without processor intervention. This reduces the processor overhead when dealing with transfers of continuous data
streams.The AT91RM9200 benefits from a new generation of PDC which includes dual pointers
that simplify significantly buffer chaining.
The set of Parallel I/O (PIO) controllers multiplex the peripheral input/output lines with generalpurpose data I/Os for maximum flexibility in device configuration. An input change interrupt,
open drain capability and programmable pull-up resistor is included on each line.
The Power Management Controller (PMC) keeps system power consumption to a minimum by
selectively enabling/disabling the processor and various peripherals under software control. It
uses an enhanced clock generator to provide a selection of clock signals including a slow clock
(32 kHz) to optimize power consumption and performance at all times.
The AT91RM9200 integrates a wide range of standard interfaces including USB 2.0 Full Speed
Host and Device and Ethernet 10/100 Base-T Media Access Controller (MAC), which provides
connection to a extensive range of external peripheral devices and a widely used networking
layer. In addition, it provides an extensive set of peripherals that operate in accordance with several industry standards, such as those used in audio, telecom, Flash Card, infrared and Smart
Card applications.
To complete the offer, the AT91RM9200 benefits from the integration of a wide range of debug
features including JTAG-ICE, a dedicated UART debug channel (DBGU) and an embedded real
time trace. This enables the development and debug of all applications, especially those with
real-time constraints.
2
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
2. Block Diagram
Bold arrows (
AT91RM9200 Block Diagram
NRST
Reset
and
Test
IRQ0-IRQ6
JTAG
Scan
ETM
Instruction Cache
16K bytes
MMU
PLLRCB
AIC
Fast SRAM
16K bytes
Address
Decoder
EBI
Fast ROM
128K bytes
PLLA
XIN
PMC
OSC
XOUT
Misalignment
Detector
Bus
Arbiter
Peripheral
Bridge
System
Timer
Peripheral
DMA
Controller
XIN32
OSC
XOUT32
DRXD
CompactFlash
NAND Flash
SmartMedia
Abort
Status
PLLB
PLLRCA
SDRAM
Controller
Memory
Controller
Burst
Flash
Controller
RTC
Static
Memory
Controller
DBGU
PIO
PDC
PIOA/PIOB/PIOC/PIOD
Controller
DDM
DDP
MCCK
MCCDA
MCDA0-MCDA3
MCCDB
MCDB0-MCDB3
FIFO
USB Host
DMA
HDMA
HDPA
HDMB
HDPB
FIFO
ETXCK-ERXCK-EREFCK
ETXEN-ETXER
ECRS-ECOL
ERXER-ERXDV
ERX0-ERX3
ETX0-ETX3
EMDC
EMDIO
EF100
Ethernet MAC 10/100
PDC
APB
SSC0
TF0
TK0
TD0
RD0
RK0
RF0
SSC1
TF1
TK1
TD1
RD1
RK1
RF1
USART0
PDC
PDC
PDC
USART2
RXD3
TXD3
SCK3
RTS3
CTS3
USART3
PDC
SSC2
PDC
PDC
Timer Counter
PDC
TC0
TC1
TC2
PIO
PIO
PIO
USART1
RXD2
TXD2
SCK2
RTS2
CTS2
TF2
TK2
TD2
RD2
RK2
RF2
TCLK0
TCLK1
TCLK2
TIOA0
TIOB0
TIOA1
TIOB1
TIOA2
TIOB2
SPI
Timer Counter
PDC
TC3
TWD
TWI
TWCK
D0-D15
A0/NBS0
A1/NBS2/NWR2
A2-A15/A18-A22
A16/BA0
A17/BA1
NCS0/BFCS
NCS1/SDCS
NCS2
NCS3/SMCS
NRD/NOE/CFOE
NWR0/NWE/CFWE
NWR1/NBS1/CFIOR
NWR3/NBS3/CFIOW
SDCK
SDCKE
RAS-CAS
SDWE
SDA10
BFRDY/SMOE
BFCK
BFAVD
BFBAA/SMWE
BFOE
BFWE
A23-A24
A25/CFRNW
NWAIT
NCS4/CFCS
NCS5/CFCE1
NCS6/CFCE2
NCS7
D16-D31
USB Device
MCI
RXD0
TXD0
SCK0
RTS0
CTS0
NPCS0
NPCS1
NPCS2
NPCS3
MISO
MOSI
SPCK
FIFO
Transceiver
Transceiver
DMA
RXD1
TXD1
SCK1
RTS1
CTS1
DSR1
DTR1
DCD1
RI1
TPS0 - TPS2
TPK0 - TPK15
Data Cache
16K bytes
PCK0-PCK3
DTXD
TCLK
BMS
PIO
FIQ
TSYNC
ARM920T Core
ICE
JTAGSEL
TDI
TDO
TMS
TCK
NTRST
PIO
TST0-TST1
PIO
Figure 2-1.
) indicate master-to-slave dependency.
TC4
TC5
TCLK3
TCLK4
TCLK5
TIOA3
TIOB3
TIOA4
TIOB4
TIOA5
TIOB5
3
1768I–ATARM–09-Jul-09
3. Signal Description
Table 3-1.
Pin Name
Signal Description by Peripheral
Function
Type
Active
Level
Comments
Power
VDDIOM
Memory I/O Lines Power Supply
Power
3.0V to 3.6V
VDDIOP
Peripheral I/O Lines Power Supply
Power
3.0V to 3.6V
VDDPLL
Oscillator and PLL Power Supply
Power
1.65V to 1.95V
VDDCORE
Core Chip Power Supply
Power
1.65V to 1.95V
VDDOSC
Oscillator Power Supply
Power
1.65V to 1.95V
GND
Ground
Ground
GNDPLL
PLL Ground
Ground
GNDOSC
Oscillator Ground
Ground
XIN
Main Crystal Input
XOUT
Main Crystal Output
XIN32
32KHz Crystal Input
XOUT32
32KHz Crystal Output
PLLRCA
PLL A Filter
PLLRCB
PLL B Filter
PCK0 - PCK3
Programmable Clock Output
Clocks, Oscillators and PLLs
Input
Output
Input
Output
Input
Input
Output
ICE and JTAG
TCK
Test Clock
Input
Schmitt trigger
TDI
Test Data In
Input
Internal Pull-up, Schmitt trigger
TDO
Test Data Out
Output
TMS
Test Mode Select
Input
NTRST
Test Reset Signal
Input
JTAGSEL
JTAG Selection
Input
Tri-state
Internal Pull-up, Schmitt trigger
Low
Internal Pull-up, Schmitt trigger
Schmitt trigger
ETM™
TSYNC
Trace Synchronization Signal
Output
TCLK
Trace Clock
Output
TPS0 - TPS2
Trace ARM Pipeline Status
Output
TPK0 - TPK15
Trace Packet Port
Output
Reset/Test
4
NRST
Microcontroller Reset
Input
TST0 - TST1
Test Mode Select
Input
Low
No on-chip pull-up, Schmitt trigger
Must be tied low for normal
operation, Schmitt trigger
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table 3-1.
Signal Description by Peripheral
Pin Name
Function
Type
Active
Level
Comments
Memory Controller
BMS
Boot Mode Select
Input
Debug Unit
DRXD
Debug Receive Data
Input
Debug Receive Data
DTXD
Debug Transmit Data
Output
Debug Transmit Data
AIC
IRQ0 - IRQ6
External Interrupt Inputs
Input
FIQ
Fast Interrupt Input
Input
PIO
PA0 - PA31
Parallel IO Controller A
I/O
Pulled-up input at reset
PB0 - PB29
Parallel IO Controller B
I/O
Pulled-up input at reset
PC0 - PC31
Parallel IO Controller C
I/O
Pulled-up input at reset
PD0 - PD27
Parallel IO Controller D
I/O
Pulled-up input at reset
I/O
Pulled-up input at reset
EBI
D0 - D31
Data Bus
A0 - A25
Address Bus
Output
0 at reset
SMC
NCS0 - NCS7
Chip Select Lines
Output
Low
1 at reset
NWR0 - NWR3
Write Signal
Output
Low
1 at reset
NOE
Output Enable
Output
Low
1 at reset
NRD
Read Signal
Output
Low
1 at reset
NUB
Upper Byte Select
Output
Low
1 at reset
NLB
Lower Byte Select
Output
Low
1 at reset
NWE
Write Enable
Output
Low
1 at reset
NWAIT
Wait Signal
Input
Low
NBS0 - NBS3
Byte Mask Signal
Output
Low
1 at reset
EBI for CompactFlash Support
CFCE1 - CFCE2
CompactFlash Chip Enable
Output
Low
CFOE
CompactFlash Output Enable
Output
Low
CFWE
CompactFlash Write Enable
Output
Low
CFIOR
CompactFlash IO Read
Output
Low
CFIOW
CompactFlash IO Write
Output
Low
CFRNW
CompactFlash Read Not Write
Output
CFCS
CompactFlash Chip Select
Output
Low
5
1768I–ATARM–09-Jul-09
Table 3-1.
Signal Description by Peripheral
Pin Name
Function
Type
Active
Level
Comments
EBI for NAND Flash/SmartMedia Support
SMCS
NAND Flash/SmartMedia Chip Select
Output
Low
SMOE
NAND Flash/SmartMedia Output Enable
Output
Low
SMWE
NAND Flash/SmartMedia Write Enable
Output
Low
SDRAM Controller
SDCK
SDRAM Clock
Output
SDCKE
SDRAM Clock Enable
Output
High
SDCS
SDRAM Controller Chip Select
Output
Low
BA0 - BA1
Bank Select
Output
SDWE
SDRAM Write Enable
Output
Low
RAS - CAS
Row and Column Signal
Output
Low
SDA10
SDRAM Address 10 Line
Output
Burst Flash Controller
BFCK
Burst Flash Clock
Output
BFCS
Burst Flash Chip Select
Output
Low
BFAVD
Burst Flash Address Valid
Output
Low
BFBAA
Burst Flash Address Advance
Output
Low
BFOE
Burst Flash Output Enable
Output
Low
BFRDY
Burst Flash Ready
Input
High
BFWE
Burst Flash Write Enable
Output
Low
Multimedia Card Interface
MCCK
Multimedia Card Clock
Output
MCCDA
Multimedia Card A Command
I/O
MCDA0 - MCDA3
Multimedia Card A Data
I/O
MCCDB
Multimedia Card B Command
I/O
MCDB0 - MCDB3
Multimedia Card B Data
I/O
USART
6
SCK0 - SCK3
Serial Clock
I/O
TXD0 - TXD3
Transmit Data
Output
RXD0 - RXD3
Receive Data
Input
RTS0 - RTS3
Ready To Send
Output
CTS0 - CTS3
Clear To Send
Input
DSR1
Data Set Ready
Input
DTR1
Data Terminal Ready
DCD1
Data Carrier Detect
Input
RI1
Ring Indicator
Input
Output
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table 3-1.
Signal Description by Peripheral
Pin Name
Function
Type
Active
Level
Comments
USB Device Port
DDM
USB Device Port Data -
Analog
DDP
USB Device Port Data +
Analog
USB Host Port
HDMA
USB Host Port A Data -
Analog
HDPA
USB Host Port A Data +
Analog
HDMB
USB Host Port B Data -
Analog
HDPB
USB Host Port B Data +
Analog
Ethernet MAC
EREFCK
Reference Clock
Input
RMII only
ETXCK
Transmit Clock
Input
MII only
ERXCK
Receive Clock
Input
MII only
ETXEN
Transmit Enable
Output
ETX0 - ETX3
Transmit Data
Output
ETX0 - ETX1 only in RMII
ETXER
Transmit Coding Error
Output
MII only
ERXDV
Receive Data Valid
Input
MII only
ECRSDV
Carrier Sense and Data Valid
Input
RMII only
ERX0 - ERX3
Receive Data
Input
ERX0 - ERX1 only in RMII
ERXER
Receive Error
Input
ECRS
Carrier Sense
Input
MII only
ECOL
Collision Detected
Input
MII only
EMDC
Management Data Clock
EMDIO
Management Data Input/Output
EF100
Force 100 Mbits/sec.
Output
I/O
Output
High
RMII only
Synchronous Serial Controller
TD0 - TD2
Transmit Data
Output
RD0 - RD2
Receive Data
Input
TK0 - TK2
Transmit Clock
I/O
RK0 - RK2
Receive Clock
I/O
TF0 - TF2
Transmit Frame Sync
I/O
RF0 - RF2
Receive Frame Sync
I/O
Timer/Counter
TCLK0 - TCLK5
External Clock Input
Input
TIOA0 - TIOA5
I/O Line A
I/O
TIOB0 - TIOB5
I/O Line B
I/O
7
1768I–ATARM–09-Jul-09
Table 3-1.
Signal Description by Peripheral
Pin Name
Function
Type
Active
Level
Comments
SPI
MISO
Master In Slave Out
I/O
MOSI
Master Out Slave In
I/O
SPCK
SPI Serial Clock
I/O
NPCS0
SPI Peripheral Chip Select 0
I/O
Low
NPCS1 - NPCS3
SPI Peripheral Chip Select
Output
Low
Two-Wire Interface
TWD
Two-wire Serial Data
I/O
TWCK
Two-wire Serial Clock
I/O
4. Package and Pinout
The AT91RM9200 is available in two packages:
• 208-pin PQFP, 31.2 x 31.2 mm, 0.5 mm pitch
• 256-ball BGA, 15 x 15 mm, 0.8 mm ball pitch
The product features of the 256-ball BGA package are extended compared to the 208-lead
PQFP package. The features that are available only with the 256-ball BGA package are:
• Parallel I/O Controller D
• ETM™ port with outputs multiplexed on the PIO Controller D
• a second USB Host transceiver, opening the Hub capabilities of the embedded USB Host.
4.1
208-pin PQFP Package Outline
Figure 4-1 shows the orientation of the 208-pin PQFP package.
A detailed mechanical description is given in the section “AT91RM9200 Mechanical Characteristics” of the product datasheet.
Figure 4-1.
208-pin PQFP Package (Top View)
156
105
104
157
208
53
1
8
52
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
4.2
208-pin PQFP Package Pinout
Table 4-1.
AT91RM9200 Pinout for 208-pin PQFP Package
Pin
Number
Signal Name
Pin
Number
Signal Name
Pin
Number
Signal Name
Pin
Number
Signal Name
1
PC24
37
VDDPLL
73
PA27
109
TMS
2
PC25
38
PLLRCB
74
PA28
110
NTRST
3
PC26
39
GNDPLL
75
VDDIOP
111
VDDIOP
4
PC27
40
VDDIOP
76
GND
112
GND
5
PC28
41
GND
77
PA29
113
TST0
6
PC29
42
PA0
78
PA30
114
TST1
7
VDDIOM
43
PA1
79
PA31/BMS
115
NRST
8
GND
44
PA2
80
PB0
116
VDDCORE
9
PC30
45
PA3
81
PB1
117
GND
10
PC31
46
PA4
82
PB2
118
PB23
11
PC10
47
PA5
83
PB3
119
PB24
12
PC11
48
PA6
84
PB4
120
PB25
13
PC12
49
PA7
85
PB5
121
PB26
14
PC13
50
PA8
86
PB6
122
PB27
15
PC14
51
PA9
87
PB7
123
PB28
16
PC15
52
PA10
88
PB8
124
PB29
17
PC0
53
PA11
89
PB9
125
HDMA
18
PC1
54
PA12
90
PB10
126
HDPA
19
VDDCORE
55
PA13
91
PB11
127
DDM
20
GND
56
VDDIOP
92
PB12
128
DDP
21
PC2
57
GND
93
VDDIOP
129
VDDIOP
22
PC3
58
PA14
94
GND
130
GND
23
PC4
59
PA15
95
PB13
131
VDDIOM
24
PC5
60
PA16
96
PB14
132
GND
25
PC6
61
PA17
97
PB15
133
A0/NBS0
26
VDDIOM
62
VDDCORE
98
PB16
134
A1/NBS2/NWR2
27
GND
63
GND
99
PB17
135
A2
28
VDDPLL
64
PA18
100
PB18
136
A3
29
PLLRCA
65
PA19
101
PB19
137
A4
30
GNDPLL
66
PA20
102
PB20
138
A5
31
XOUT
67
PA21
103
PB21
139
A6
32
XIN
68
PA22
104
PB22
140
A7
33
VDDOSC
69
PA23
105
JTAGSEL
141
A8
34
GNDOSC
70
PA24
106
TDI
142
A9
35
XOUT32
71
PA25
107
TDO
143
A10
36
XIN32
72
PA26
108
TCK
144
SDA10
9
1768I–ATARM–09-Jul-09
Table 4-1.
AT91RM9200 Pinout for 208-pin PQFP Package (Continued)
Pin
Number
Signal Name
Pin
Number
Signal Name
Pin
Number
Signal Name
Pin
Number
Signal Name
145
A11
161
PC7
177
CAS
193
D10
146
VDDIOM
162
PC8
178
SDWE
194
D11
147
GND
163
PC9
179
D0
195
D12
148
A12
164
VDDIOM
180
D1
196
D13
149
A13
165
GND
181
D2
197
D14
150
A14
166
NCS0/BFCS
182
D3
198
D15
151
A15
167
NCS1/SDCS
183
VDDIOM
199
VDDIOM
152
VDDCORE
168
NCS2
184
GND
200
GND
153
GND
169
NCS3/SMCS
185
D4
201
PC16
154
A16/BA0
170
NRD/NOE/CFOE
186
D5
202
PC17
155
A17/BA1
171
NWR0/NWE/CFWE
187
D6
203
PC18
156
A18
172
NWR1/NBS1/CFIOR
188
VDDCORE
204
PC19
157
A19
173
NWR3/NBS3/CFIOW
189
GND
205
PC20
158
A20
174
SDCK
190
D7
206
PC21
159
A21
175
SDCKE
191
D8
207
PC22
160
A22
176
RAS
192
D9
208
PC23
Note:
1. Shaded cells define the pins powered by VDDIOM.
4.3
256-ball BGA Package Outline
Figure 4-2 shows the orientation of the 256-ball LFBGA package.
A detailed mechanical description is given in the section “AT91RM9200 Mechanical Characteristics” of the product datasheet.
Figure 4-2.
256-ball LFBGA Package (Top View)
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
BALL A1
10
A B C D E F G H J K L M N P R T U
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
4.4
256-ball BGA Package Pinout
Table 4-2.
AT91RM9200 Pinout for 256-ball BGA Package
Pin
Signal Name
Pin
Signal Name
Pin
Signal Name
Pin
Signal Name
A1
TDI
C3
PD14
E5
TCK
G14
PA1
A2
JTAGSEL
C4
PB22
E6
GND
G15
PA2
A3
PB20
C5
PB19
E7
PB15
G16
PA3
A4
PB17
C6
PD10
E8
GND
G17
XIN32
A5
PD11
C7
PB13
E9
PB7
H1
PD23
A6
PD8
C8
PB12
E10
PB3
H2
PD20
A7
VDDIOP
C9
PB6
E11
PA29
H3
PD22
A8
PB9
C10
PB1
E12
PA26
H4
PD21
A9
PB4
C11
GND
E13
PA25
H5
VDDIOP
A10
PA31/BMS
C12
PA20
E14
PA9
H13
VDDPLL
A11
VDDIOP
C13
PA18
E15
PA6
H14
VDDIOP
A12
PA23
C14
VDDCORE
E16
PD3
H15
GNDPLL
A13
PA19
C15
GND
E17
PD0
H16
GND
A14
GND
C16
PA8
F1
PD16
H17
XOUT32
A15
PA14
C17
PD5
F2
GND
J1
PD25
A16
VDDIOP
D1
TST1
F3
PB23
J2
PD27
A17
PA13
D2
VDDIOP
F4
PB25
J3
PD24
B1
TDO
D3
VDDIOP
F5
PB24
J4
PD26
B2
PD13
D4
GND
F6
VDDCORE
J5
PB28
B3
PB18
D5
VDDIOP
F7
PB16
J6
PB29
B4
PB21
D6
PD7
F9
PB11
J12
GND
B5
PD12
D7
PB14
F11
PA30
J13
GNDOSC
B6
PD9
D8
VDDIOP
F12
PA28
J14
VDDOSC
B7
GND
D9
PB8
F13
PA4
J15
VDDPLL
B8
PB10
D10
PB2
F14
PD2
J16
GNDPLL
B9
PB5
D11
GND
F15
PD1
J17
XIN
B10
PB0
D12
PA22
F16
PA5
K1
HDPA
B11
VDDIOP
D13
PA21
F17
PLLRCB
K2
DDM
B12
PA24
D14
PA16
G1
PD19
K3
HDMA
B13
PA17
D15
PA10
G2
PD17
K4
VDDIOP
B14
PA15
D16
PD6
G3
GND
K5
DDP
B15
PA11
D17
PD4
G4
PB26
K13
PC5
B16
PA12
E1
NRST
G5
PD18
K14
PC4
B17
PA7
E2
NTRST
G6
PB27
K15
PC6
C1
TMS
E3
GND
G12
PA27
K16
VDDIOM
C2
PD15
E4
TST0
G13
PA0
K17
XOUT
11
1768I–ATARM–09-Jul-09
Table 4-2.
AT91RM9200 Pinout for 256-ball BGA Package (Continued)
Pin
Signal Name
Pin
Signal Name
Pin
Signal Name
Pin
Signal Name
L1
GND
N2
A5
P13
D15
T7
NWR1/NBS1/
CFIOR
L2
HDPB
N3
A9
P14
PC26
T8
SDWE
L3
HDMB
N4
A4
P15
PC27
T9
GND
L4
A6
N5
A14
P16
VDDIOM
T10
VDDCORE
L5
GND
N6
SDA10
P17
GND
T11
D9
L6
VDDIOP
N7
A8
R1
GND
T12
D12
L12
PC10
N8
A21
R2
GND
T13
GND
L13
PC15
N9
NRD/NOE/CFOE
R3
A18
T14
PC19
L14
PC2
N10
RAS
R4
A20
T15
PC21
L15
PC3
N11
D2
R5
PC8
T16
PC23
L16
VDDCORE
N12
GND
R6
VDDIOM
T17
PC25
L17
PLLRCA
N13
PC28
R7
NCS3/SMCS
U1
VDDCORE
M1
VDDIOM
N14
PC31
R8
NWR3/NBS3/
CFIOW
U2
GND
M2
GND
N15
PC30
R9
D0
U3
A16/BA0
M3
A3
N16
PC11
R10
VDDIOM
U4
A19
M4
A1/NBS2/NWR2
N17
PC12
R11
D8
U5
GND
M5
A10
P1
A7
R12
D13
U6
NCS0/BFCS
M6
A2
P2
A13
R13
PC17
U7
SDCK
M7
GND
P3
A12
R14
VDDIOM
U8
CAS
M9
NCS1/SDCS
P4
VDDIOM
R15
PC24
U9
D3
M11
D4
P5
A11
R16
PC29
U10
D6
M12
GND
P6
A22
R17
VDDIOM
U11
D7
M13
PC13
P7
PC9
T1
A15
U12
D11
M14
PC1
P8
NWR0/NWE/CFWE
T2
VDDCORE
U13
D14
M15
PC0
P9
SDCKE
T3
A17/BA1
U14
PC16
M16
GND
P10
D1
T4
PC7
U15
PC18
M17
PC14
P11
D5
T5
VDDIOM
U16
PC20
N1
A0/NBS0
P12
D10
T6
NCS2
U17
PC22
Note:
12
1. Shaded cells define the balls powered by VDDIOM.
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
5. Power Considerations
5.1
Power Supplies
The AT91RM9200 has five types of power supply pins:
• VDDCORE pins. They power the core, including processor, memories and peripherals;
voltage ranges from 1.65V to 1.95V, 1.8V nominal.
• VDDIOM pins. They power the External Bus Interface I/O lines; voltage ranges from 3.0V to
3.6V, 3V or 3.3V nominal.
• VDDIOP pins. They power the Peripheral I/O lines and the USB transceivers; voltage ranges
from 3.0V to 3.6V, 3V or 3.3V nominal.
• VDDPLL pins. They power the PLL cells; voltage ranges from 1.65V to 1.95V, 1.8V nominal.
• VDDOSC pin. They power both oscillators; voltage ranges from 1.65V to 1.95V, 1.8V
nominal.
The double power supplies VDDIOM and VDDIOP are identified in Table 4-1 on page 9 and
Table 4-2 on page 11. These supplies enable the user to power the device differently for interfacing with memories and for interfacing with peripherals.
Ground pins are common to all power supplies, except VDDPLL and VDDOSC pins. For these
pins, GNDPLL and GNDOSC are provided, respectively.
5.2
Power Consumption
The AT91RM9200 consumes about 500 µA of static current on VDDCORE at 25⋅ C. For
dynamic power consumption, the AT91RM9200 consumes a maximum of 25 mA on VDDCORE
at maximum speed in typical conditions (1.8V, 25⋅ C), processor running full-performance
algorithm.
6. I/O Considerations
6.1
JTAG Port Pins
TMS and TDI are Schmitt trigger inputs and integrate internal pull-up resistors of 15 kOhm typical. TCK is a Schmitt trigger input without internal pull-up resistor.
TDO is a tri-state output. The JTAGSEL pin is used to select the JTAG boundary scan when
asserted at a high level. The NTRST pin is used to initialize the EmbeddedICE™ TAP Controller.
6.2
Test Pin
The TST0 and TST1 pins are used for manufacturing test purposes when asserted high. As they
do not integrate a pull-down resistor, they must be tied low during normal operations. Driving this
line at a high level leads to unpredictable results.
6.3
Reset Pin
NRST is a Schmitt trigger without pull-up resistor. The NRST signal is inserted in the Boundary
Scan.
13
1768I–ATARM–09-Jul-09
6.4
PIO Controller A, B, C and D Lines
All the I/O lines PA0 to PA31, PB0 to PB29, PC0 to PC31 and PD0 to PD27 integrate a programmable pull-up resistor of 15 kOhm typical. Programming of this pull-up resistor is performed
independently for each I/O line through the PIO Controllers.
After reset, all the I/O lines default as inputs with pull-up resistors enabled, except those which
are multiplexed with the External Bus Interface signals that must be enabled as peripherals at
reset. This is explicitly indicated in the column "Reset State" of the PIO Controller multiplexing
tables.
7. Processor and Architecture
7.1
ARM920T Processor
• ARM9TDMI™-based on ARM Architecture v4T
• Two instruction sets
– ARM High-performance 32-bit Instruction Set
– Thumb High Code Density 16-bit Instruction Set
• 5-Stage Pipeline Architecture:
– Instruction Fetch (F)
– Instruction Decode (D)
– Execute (E)
– Data Memory (M)
– Register Write (W)
• 16-Kbyte Data Cache, 16-Kbyte Instruction Cache
– Virtually-addressed 64-way Associative Cache
– 8 words per line
– Write-though and write-back operation
– Pseudo-random or Round-robin replacement
– Low-power CAM RAM implementation
• Write Buffer
– 16-word Data Buffer
– 4-address Address Buffer
– Software Control Drain
• Standard ARMv4 Memory Management Unit (MMU)
– Access permission for sections
– Access permission for large pages and small pages can be specified separately for
each quarter of the pages
– 16 embedded domains
– 64 Entry Instruction TLB and 64 Entry Data TLB
8-, 16-, 32-bit Data Bus for Instructions and Data
7.2
Debug and Test
• Integrated EmbeddedICE
14
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
• Debug Unit
– Two-pin UART
– Debug Communication Channel
– Chip ID Register
• Embedded Trace Macrocell: ETM9™ Rev2a
– Medium Level Implementation
– Half-rate Clock Mode
– Four Pairs of Address Comparators
– Two Data Comparators
– Eight Memory Map Decoder Inputs
– Two Counters
– One Sequencer
– One 18-byte FIFO
• IEEE1149.1 JTAG Boundary Scan on all Digital Pins
7.3
Boot Program
• Default Boot Program stored in ROM-based products
• Downloads and runs an application from external storage media into internal SRAM
• Downloaded code size depends on embedded SRAM size
• Automatic detection of valid application
• Bootloader supporting a wide range of non-volatile memories
– SPI DataFlash® connected on SPI NPCS0
– Two-wire EEPROM
– 8-bit parallel memories on NCS0
• Boot Uploader in case no valid program is detected in external NVM and supporting several
communication media
• Serial communication on a DBGU (XModem protocol)
• USB Device Port (DFU Protocol)
7.4
Embedded Software Services
• Compliant with ATPCS
• Compliant with AINSI/ISO Standard C
• Compiled in ARM/Thumb Interworking
• ROM Entry Service
• Tempo, Xmodem and DataFlash services
• CRC and Sine tables
7.5
Memory Controller
• Programmable Bus Arbiter handling four Masters
– Internal Bus is shared by ARM920T, PDC, USB Host Port and Ethernet MAC
Masters
– Each Master can be assigned a priority between 0 and 7
15
1768I–ATARM–09-Jul-09
• Address Decoder provides selection for
– Eight external 256-Mbyte memory areas
– Four internal 1-Mbyte memory areas
– One 256-Mbyte embedded peripheral area
• Boot Mode Select Option
– Non-volatile Boot Memory can be internal or external
– Selection is made by BMS pin sampled at reset
• Abort Status Registers
– Source, Type and all parameters of the access leading to an abort are saved
• Misalignment Detector
– Alignment checking of all data accesses
– Abort generation in case of misalignment
• Remap command
– Provides remapping of an internal SRAM in place of the boot NVM
16
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
8. Memories
Figure 8-1.
AT91RM9200 Memory Mapping
Internal Memory Mapping
Address Memory Space
0x0000 0000
0x0000 0000
Boot Memory (1)
Internal Memories
256M Bytes
ROM
1 MBytes
SRAM
1 MBytes
USB Host
User Interface
1 MBytes
0x0FFF FFFF
0x1000 0000
0x1FFF FFFF
0x0020 0000
EBI
Chip Select 0 /
BFC
256M Bytes
0x0030 0000
0x2000 0000
0x2FFF FFFF
1 MBytes
0x0010 0000
EBI
Chip Select 1 /
SDRAMC
0x0040 0000
256M Bytes
Notes :
Undefined
(Abort)
0x3000 0000
EBI
Chip Select 2
256M Bytes
EBI
Chip Select 3 /
NANDFlash Logic
256M Bytes
EBI
Chip Select 4 /
CF Logic
256M Bytes
248 MBytes
(1) Can be SRAM, ROM or Flash depending
on BMS and the REMAP Command
0x0FFF FFFF
0x3FFF FFFF
0x4000 0000
0x4FFF FFFF
0x5000 0000
0x5FFF FFFF
0xF000 0000
0x6000 0000
0x6FFF FFFF
User Peripheral Mapping
EBI
Chip Select 5 /
CF Logic
Reserved
256M Bytes
0xFFFA 0000
TCO, TC1, TC2
16K Bytes
TC3, TC4, TC5
16K Bytes
Reserved
16K Bytes
UDP
16K Bytes
MCI
16K Bytes
TWI
16K Bytes
EMAC
16K Bytes
USART0
16K Bytes
USART1
16K Bytes
USART2
16K Bytes
USART3
16K Bytes
SSC0
16K Bytes
SSC1
16K Bytes
SSC2
16K Bytes
0x7000 0000
0xFFFA 4000
0x7FFF FFFF
EBI
Chip Select 6 /
CF Logic
256M Bytes
0xFFFA 8000
0x8000 0000
EBI
Chip Select 7
256M Bytes
0x8FFF FFFF
0xFFFB 0000
0xFFFB 4000
0x9000 0000
System Peripheral Mapping
0xFFFB 8000
0xFFFE 4000
0xFFFB C000
Reserved
0xFFFC 0000
0xFFFF F000
0xFFFC 4000
0xFFFC 8000
Undefined
(Abort)
1,518M Bytes
0xFFFF FFFF
16K Bytes
0xFFFF FFFF
512 Bytes
PIOC
512 bytes
PIOD
512 bytes
PMC
256 Bytes
ST
256 Bytes
RTC
256 Bytes
MC
256 Bytes
0xFFFF FE00
0xFFFE 4000
Reserved
PIOB
0xFFFF FD00
0xFFFE 0000
256M Bytes
512 Bytes
0xFFFF FC00
0xFFFD C000
Internal Peripherals
PIOA
0xFFFF FA00
0xFFFD 8000
0xEFFF FFFF
512 Bytes
0xFFFF F800
0xFFFD 4000
0xF000 0000
DBGU
0xFFFF F600
0xFFFD 0000
SPI
512 Bytes
0xFFFF F400
0xFFFC C000
Reserved
AIC
0xFFFF F200
0xFFFF FF00
0xFFFF FFFF
17
1768I–ATARM–09-Jul-09
A first level of address decoding is performed by the Memory Controller, i.e., by the implementation of the Advanced System Bus (ASB) with additional features.
Decoding splits the 4G bytes of address space into 16 areas of 256M bytes. The areas 1 to 8 are
directed to the EBI that associates these areas to the external chip selects NC0 to NCS7. The
area 0 is reserved for the addressing of the internal memories, and a second level of decoding
provides 1M bytes of internal memory area. The area 15 is reserved for the peripherals and provides access to the Advanced Peripheral Bus (APB).
Other areas are unused and performing an access within them provides an abort to the master
requesting such an access.
8.1
8.1.1
Embedded Memories
Internal Memory Mapping
8.1.1.1
Internal RAM
The AT91RM9200 integrates a high-speed, 16-Kbyte internal SRAM. After reset and until the
Remap Command is performed, the SRAM is only accessible at address 0x20 0000. After
Remap, the SRAM is also available at address 0x0.
8.1.1.2
Internal ROM
The AT91RM9200 integrates a 128-Kbyte Internal ROM. At any time, the ROM is mapped at
address 0x10 0000. It is also accessible at address 0x0 after reset and before the Remap Command if the BMS is tied high during reset.
8.1.1.3
USB Host Port
The AT91RM9200 integrates a USB Host Port Open Host Controller Interface (OHCI). The registers of this interface are directly accessible on the ASB Bus and are mapped like a standard
internal memory at address 0x30 0000.
18
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
9. System Peripherals
A complete memory map is shown in Figure 8-1 on page 17.
9.1
Reset Controller
• Two reset input lines (NRST and NTRST) providing, respectively:
• Initialization of the User Interface registers (defined in the user interface of each peripheral)
and:
– Sample the signals needed at bootup
– Compel the processor to fetch the next instruction at address zero
• Initialization of the embedded ICE TAP controller
9.2
Advanced Interrupt Controller
• Controls the interrupt lines (nIRQ and nFIQ) of an ARM Processor
• Thirty-two individually maskable and vectored interrupt sources
– Source 0 is reserved for the Fast Interrupt Input (FIQ)
– Source 1 is reserved for system peripherals (ST, RTC, PMC, DBGU…)
– Source 2 to Source 31 control thirty embedded peripheral interrupts or external
interrupts
– Programmable Edge-triggered or Level-sensitive Internal Sources
– Programmable Positive/Negative Edge-triggered or High/Low Level-sensitive
External Sources
• 8-level Priority Controller
– Drives the Normal Interrupt of the processor
– Handles priority of the interrupt sources 1 to 31
– Higher priority interrupts can be served during service of lower priority interrupt
• Vectoring
– Optimizes Interrupt Service Routine Branch and Execution
– One 32-bit Vector Register per interrupt source
– Interrupt Vector Register reads the corresponding current Interrupt Vector
• Protect Mode
– Easy debugging by preventing automatic operations
• General Interrupt Mask
– Provides processor synchronization on events without triggering an interrupt
9.3
Power Management Controller
• Optimizes the power consumption of the whole system
• Embeds and controls:
– One Main Oscillator and One Slow Clock Oscillator (32.768Hz)
– Two Phase Locked Loops (PLLs) and Dividers
– Clock Prescalers
• Provides:
– the Processor Clock PCK
19
1768I–ATARM–09-Jul-09
– the Master Clock MCK
– the USB Clocks, UHPCK and UDPCK, respectively for the USB Host Port and the
USB Device Port
– Programmable automatic PLL switch-off in USB Device suspend conditions
– up to thirty peripheral clocks
– four programmable clock outputs PCK0 to PCK3
• Four operating modes:
– Normal Mode, Idle Mode, Slow Clock Mode, Standby Mode
9.4
Debug Unit
• System peripheral to facilitate debug of Atmel’s ARM-based systems
• Composed of the following functions
– Two-pin UART
– Debug Communication Channel (DCC) support
– Chip ID Registers
• Two-pin UART
– Implemented features are 100% compatible with the standard Atmel USART
– Independent receiver and transmitter with a common programmable Baud Rate
Generator
– Even, Odd, Mark or Space Parity Generation
– Parity, Framing and Overrun Error Detection
– Automatic Echo, Local Loopback and Remote Loopback Channel Modes
– Interrupt generation
– Support for two PDC channels with connection to receiver and transmitter
• Debug Communication Channel Support
– Offers visibility of COMMRX and COMMTX signals from the ARM Processor
– Interrupt generation
• Chip ID Registers
– Identification of the device revision, sizes of the embedded memories, set of
peripherals
9.5
PIO Controller
• Up to 32 programmable I/O Lines
• Fully programmable through Set/Clear Registers
• Multiplexing of two peripheral functions per I/O Line
• For each I/O Line (whether assigned to a peripheral or used as general purpose I/O)
– Input change interrupt
– Glitch filter
– Multi-drive option enables driving in open drain
– Programmable pull-up on each I/O line
– Pin data status register, supplies visibility of the level on the pin at any time
20
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
• Synchronous output, provides Set and Clear of several I/O lines in a single write
10. User Peripherals
10.1
User Interface
The User Peripherals are mapped in the upper 256M bytes of the address space, between the
addresses 0xFFFA 0000 and 0xFFFE 3FFF. Each peripheral has a 16-Kbyte address space.
A complete memory map is presented in Figure 8-1 on page 17.
10.2
Peripheral Identifiers
The AT91RM9200 embeds a wide range of peripherals. Table 10-1 defines the peripheral identifiers of the AT91RM9200. A peripheral identifier is required for the control of the peripheral
interrupt with the Advanced Interrupt Controller and for the control of the peripheral clock with
the Power Management Controller.
Table 10-1.
Peripheral Identifiers
Peripheral
Peripheral
Peripheral
External
ID
Mnemonic
Name
Interrupt
0
AIC
Advanced Interrupt Controller
FIQ
1
SYSIRQ
2
PIOA
Parallel I/O Controller A
3
PIOB
Parallel I/O Controller B
4
PIOC
Parallel I/O Controller C
5
PIOD
Parallel I/O Controller D
6
US0
USART 0
7
US1
USART 1
8
US2
USART 2
9
US3
USART 3
10
MCI
Multimedia Card Interface
11
UDP
USB Device Port
12
TWI
Two-wire Interface
13
SPI
Serial Peripheral Interface
14
SSC0
Synchronous Serial Controller 0
15
SSC1
Synchronous Serial Controller 1
16
SSC2
Synchronous Serial Controller 2
17
TC0
Timer/Counter 0
18
TC1
Timer/Counter 1
19
TC2
Timer/Counter 2
20
TC3
Timer/Counter 3
21
TC4
Timer/Counter 4
22
TC5
Timer/Counter 5
23
UHP
USB Host Port
21
1768I–ATARM–09-Jul-09
Table 10-1.
10.3
Peripheral Identifiers (Continued)
Peripheral
Peripheral
Peripheral
External
ID
Mnemonic
Name
Interrupt
24
EMAC
Ethernet MAC
25
AIC
Advanced Interrupt Controller
IRQ0
26
AIC
Advanced Interrupt Controller
IRQ1
27
AIC
Advanced Interrupt Controller
IRQ2
28
AIC
Advanced Interrupt Controller
IRQ3
29
AIC
Advanced Interrupt Controller
IRQ4
30
AIC
Advanced Interrupt Controller
IRQ5
31
AIC
Advanced Interrupt Controller
IRQ6
Peripheral Multiplexing on PIO Lines
The AT91RM9200 features four PIO controllers:
• PIOA and PIOB, multiplexing I/O lines of the peripheral set
• PIOC, multiplexing the data bus bits 16 to 31 and several External Bus Interface control
signals. Using PIOC pins increases the number of general-purpose I/O lines available but
prevents 32-bit memory access
• PIOD, available in the 256-ball BGA package option only, multiplexing outputs of the
peripheral set and the ETM port
Each PIO Controller controls up to 32 lines. Each line can be assigned to one of two peripheral
functions, A or B. The tables in the following paragraphs define how the I/O lines of the peripherals A and B are multiplexed on the PIO Controllers A, B, C and D. The two columns “Function”
and “Comments” have been inserted for the user’s own comments; they may be used to track
how pins are defined in an application.
The column “Reset State” indicates whether the PIO line resets in I/O mode or in peripheral
mode. If equal to “I/O”, the PIO line resets in input with the pull-up enabled so that the device is
maintained in a static state as soon as the NRST pin is asserted. As a result, the bit corresponding to the PIO line in the register PIO_PSR (Peripheral Status Register) resets low.
If a signal name is in the “Reset State” column, the PIO line is assigned to this function and the
corresponding bit in PIO_PSR resets high. This is the case for pins controlling memories, either
address lines or chip selects, and that require the pin to be driven as soon as NRST raises. Note
that the pull-up resistor is also enabled in this case.
See Table 10-2 on page 23, Table 10-3 on page 24, Table 10-4 on page 25 and Table 10-5 on
page 26.
22
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
10.3.1
PIO Controller A Multiplexing
Table 10-2.
Multiplexing on PIO Controller A
PIO Controller A
Application Usage
Reset
State
I/O Line
Peripheral A
Peripheral B
PA0
MISO
PCK3
I/O
PA1
MOSI
PCK0
I/O
PA2
SPCK
IRQ4
I/O
PA3
NPCS0
IRQ5
I/O
PA4
NPCS1
PCK1
I/O
PA5
NPCS2
TXD3
I/O
PA6
NPCS3
RXD3
I/O
PA7
ETXCK/EREFCK
PCK2
I/O
PA8
ETXEN
MCCDB
I/O
PA9
ETX0
MCDB0
I/O
PA10
ETX1
MCDB1
I/O
PA11
ECRS/ECRSDV
MCDB2
I/O
PA12
ERX0
MCDB3
I/O
PA13
ERX1
TCLK0
I/O
PA14
ERXER
TCLK1
I/O
PA15
EMDC
TCLK2
I/O
PA16
EMDIO
IRQ6
I/O
PA17
TXD0
TIOA0
I/O
PA18
RXD0
TIOB0
I/O
PA19
SCK0
TIOA1
I/O
PA20
CTS0
TIOB1
I/O
PA21
RTS0
TIOA2
I/O
PA22
RXD2
TIOB2
I/O
PA23
TXD2
IRQ3
I/O
PA24
SCK2
PCK1
I/O
PA25
TWD
IRQ2
I/O
PA26
TWCK
IRQ1
I/O
PA27
MCCK
TCLK3
I/O
PA28
MCCDA
TCLK4
I/O
PA29
MCDA0
TCLK5
I/O
PA30
DRXD
CTS2
I/O
PA31
DTXD
RTS2
I/O
Function
Comments
23
1768I–ATARM–09-Jul-09
10.3.2
PIO Controller B Multiplexing
Table 10-3.
Multiplexing on PIO Controller B
PIO Controller B
Application Usage
I/O Line
Peripheral A
Peripheral B
Reset
State
PB0
TF0
RTS3
I/O
PB1
TK0
CTS3
I/O
PB2
TD0
SCK3
I/O
PB3
RD0
MCDA1
I/O
PB4
RK0
MCDA2
I/O
PB5
RF0
MCDA3
I/O
PB6
TF1
TIOA3
I/O
PB7
TK1
TIOB3
I/O
PB8
TD1
TIOA4
I/O
PB9
RD1
TIOB4
I/O
PB10
RK1
TIOA5
I/O
PB11
RF1
TIOB5
I/O
PB12
TF2
ETX2
I/O
PB13
TK2
ETX3
I/O
PB14
TD2
ETXER
I/O
PB15
RD2
ERX2
I/O
PB16
RK2
ERX3
I/O
PB17
RF2
ERXDV
I/O
PB18
RI1
ECOL
I/O
PB19
DTR1
ERXCK
I/O
PB20
TXD1
I/O
PB21
RXD1
I/O
PB22
SCK1
I/O
PB23
DCD1
I/O
PB24
CTS1
I/O
PB25
DSR1
PB26
RTS1
I/O
PB27
PCK0
I/O
PB28
FIQ
I/O
PB29
IRQ0
I/O
24
EF100
Function
Comments
I/O
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
10.3.3
PIO Controller C Multiplexing
The PIO Controller C has no multiplexing and only peripheral A lines are used. Selecting Peripheral B on the PIO Controller
C has no effect.
Table 10-4.
Multiplexing on PIO Controller C
PIO Controller C
I/O Line
Peripheral A
Peripheral B
Application Usage
Reset
State
PC0
BFCK
I/O
PC1
BFRDY/SMOE
I/O
PC2
BFAVD
I/O
PC3
BFBAA/SMWE
I/O
PC4
BFOE
I/O
PC5
BFWE
I/O
PC6
NWAIT
I/O
PC7
A23
A23
PC8
A24
A24
PC9
A25/CFRNW
A25
PC10
NCS4/CFCS
NCS4
PC11
NCS5/CFCE1
NCS5
PC12
NCS6/CFCE2
NCS6
PC13
NCS7
NCS7
PC14
I/O
PC15
I/O
PC16
D16
I/O
PC17
D17
I/O
PC18
D18
I/O
PC19
D19
I/O
PC20
D20
I/O
PC21
D21
I/O
PC22
D22
I/O
PC23
D23
I/O
PC24
D24
I/O
PC25
D25
I/O
PC26
D26
I/O
PC27
D27
I/O
PC28
D28
I/O
PC29
D29
I/O
PC30
D30
I/O
PC31
D31
I/O
Function
Comments
25
1768I–ATARM–09-Jul-09
10.3.4
PIO Controller D Multiplexing
The PIO Controller D multiplexes pure output signals on peripheral A connections, in particular from the EMAC MII interface and the ETM Port on the peripheral B connections.
The PIO Controller D is available only in the 256-ball BGA package option of the AT91RM9200.
Table 10-5.
Multiplexing on PIO Controller D
PIO Controller D
I/O Line
26
Peripheral A
Application Usage
Peripheral B
Reset
State
PD0
ETX0
I/O
PD1
ETX1
I/O
PD2
ETX2
I/O
PD3
ETX3
I/O
PD4
ETXEN
I/O
PD5
ETXER
I/O
PD6
DTXD
I/O
PD7
PCK0
TSYNC
I/O
PD8
PCK1
TCLK
I/O
PD9
PCK2
TPS0
I/O
PD10
PCK3
TPS1
I/O
PD11
TPS2
I/O
PD12
TPK0
I/O
PD13
TPK1
I/O
PD14
TPK2
I/O
PD15
TD0
TPK3
I/O
PD16
TD1
TPK4
I/O
PD17
TD2
TPK5
I/O
PD18
NPCS1
TPK6
I/O
PD19
NPCS2
TPK7
I/O
PD20
NPCS3
TPK8
I/O
PD21
RTS0
TPK9
I/O
PD22
RTS1
TPK10
I/O
PD23
RTS2
TPK11
I/O
PD24
RTS3
TPK12
I/O
PD25
DTR1
TPK13
I/O
PD26
TPK14
I/O
PD27
TPK15
I/O
Function
Comments
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
10.3.5
System Interrupt
The System Interrupt is the wired-OR of the interrupt signals coming from:
• the Memory Controller
• the Debug Unit
• the System Timer
• the Real-Time Clock
• the Power Management Controller
The clock of these peripherals cannot be controlled and the Peripheral ID 1 can only be used
within the Advanced Interrupt Controller.
10.3.6
10.4
External Interrupts
All external interrupt signals, i.e., the Fast Interrupt signal FIQ or the Interrupt signals IRQ0 to
IRQ6, use a dedicated Peripheral ID. However, there is no clock control associated with these
peripheral IDs.
External Bus Interface
• Integrates three External Memory Controllers:
– Static Memory Controller
– SDRAM Controller
– Burst Flash Controller
• Additional logic for NAND Flash/SmartMedia and CompactFlash support
• Optimized External Bus:
– 16- or 32-bit Data Bus
– Up to 26-bit Address Bus, up to 64-Mbytes addressable
– Up to 8 Chip Selects, each reserved to one of the eight Memory Areas
– Optimized pin multiplexing to reduce latencies on External Memories
• Configurable Chip Select Assignment:
– Burst Flash Controller or Static Memory Controller on NCS0
– SDRAM Controller or Static Memory Controller on NCS1
– Static Memory Controller on NCS3, Optional NAND Flash/SmartMedia Support
– Static Memory Controller on NCS4 - NCS6, Optional CompactFlash Support
– Static Memory Controller on NCS7
10.5
Static Memory Controller
• External memory mapping, 512-Mbyte address space
• Up to 8 Chip Select Lines
• 8- or 16-bit Data Bus
• Remap of Boot Memory
• Multiple Access Modes supported
– Byte Write or Byte Select Lines
– Two different Read Protocols for each Memory Bank
• Multiple device adaptability
27
1768I–ATARM–09-Jul-09
– Compliant with LCD Module
– Programmable Setup Time Read/Write
– Programmable Hold Time Read/Write
• Multiple Wait State Management
– Programmable Wait State Generation
– External Wait Request
– Programmable Data Float Time
10.6
SDRAM Controller
• Numerous configurations supported
– 2K, 4K, 8K Row Address Memory Parts
– SDRAM with two or four Internal Banks
– SDRAM with 16- or 32-bit Data Path
• Programming facilities
– Word, half-word, 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
• Energy-saving capabilities
– Self-refresh and Low-power Modes supported
• Error detection
– Refresh Error Interrupt
• SDRAM Power-up Initialization by software
• Latency is set to two clocks (CAS Latency of 1, 3 Not Supported)
• Auto Precharge Command not used
10.7
Burst Flash Controller
• Multiple Access Modes supported
– Asynchronous or Burst Mode Byte, Half-word or Word Read Accesses
– Asynchronous Mode Half-word Write Accesses
• Adaptability to different device speed grades
– Programmable Burst Flash Clock Rate
– Programmable Data Access Time
– Programmable Latency after Output Enable
• Adaptability to different device access protocols and bus interfaces
– Two Burst Read Protocols: Clock Control Address Advance or Signal Controlled
Address Advance
– Multiplexed or separate address and data buses
– Continuous Burst and Page Mode Accesses supported
28
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
10.8
Peripheral DMA Controller (PDC)
• Generates transfers to/from peripherals such as DBGU, USART, SSC, SPI and MCI
• Twenty channels
• One Master Clock cycle needed for a transfer from memory to peripheral
• Two Master Clock cycles needed for a transfer from peripheral to memory
10.9
System Timer
• One Period Interval Timer, 16-bit programmable counter
• One Watchdog Timer, 16-bit programmable counter
• One Real-time Timer, 20-bit free-running counter
• Interrupt Generation on event
10.10 Real-time Clock
• Low power consumption
• Full asynchronous design
• Two hundred year calendar
• Programmable Periodic Interrupt
• Alarm and update parallel load
• Control of alarm and update Time/Calendar Data In
10.11 USB Host Port
• Compliance with Open HCI Rev 1.0 specification
• Compliance with USB V2.0 Full-speed and Low-speed Specification
• Supports both Low-speed 1.5 Mbps and Full-speed 12 Mbps USB devices
• Root hub integrated with two downstream USB ports
• Two embedded USB transceivers
• Supports power management
• Operates as a master on the Memory Controller
10.12 USB Device Port
• USB V2.0 full-speed compliant, 12 Mbits per second
• Embedded USB V2.0 full-speed transceiver
• Embedded dual-port RAM for endpoints
• Suspend/Resume logic
• Ping-pong mode (two memory banks) for isochronous and bulk endpoints
• Six general-purpose endpoints
– Endpoint 0, Endpoint 3: 8 bytes, no ping-pong mode
– Endpoint 1, Endpoint 2: 64 bytes, ping-pong mode
– Endpoint 4, Endpoint 5: 256 bytes, ping-pong mode
10.13 Ethernet MAC
• Compatibility with IEEE Standard 802.3
29
1768I–ATARM–09-Jul-09
• 10 and 100 Mbits per second data throughput capability
• Full- and half-duplex operation
• MII or RMII interface to the physical layer
• Register interface to address, status and control registers
• DMA interface, operating as a master on the Memory Controller
• Interrupt generation to signal receive and transmit completion
• 28-byte transmit and 28-byte receive FIFOs
• Automatic pad and CRC generation on transmitted frames
• Address checking logic to recognize four 48-bit addresses
• Supports promiscuous mode where all valid frames are copied to memory
• Supports physical layer management through MDIO interface
10.14 Serial Peripheral Interface
• 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
– 8- 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 PDC channel optimizes data transfers
– One channel for the receiver, one channel for the transmitter
– Next buffer support
10.15 Two-wire Interface
• Compatibility with standard two-wire serial memory
• One, two or three bytes for slave address
• Sequential Read/Write operations
10.16 USART
• Programmable Baud Rate Generator
• 5- to 9-bit full-duplex synchronous or asynchronous serial communications
– 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
30
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
– 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 Multi-drop 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
• Test Modes
– Remote Loopback, Local Loopback, Automatic Echo
• Connection of two Peripheral DMA Controller (PDC) channels
– Offers buffer transfer without processor intervention
The USART describes features allowing management of the Modem Signals DTR, DSR, DCD
and RI. For details, see “Modem Mode” on page 434.
In the AT91RM9200, only the USART1 implements these signals, named DTR1, DSR1, DCD1
and RI1.
The USART0, USART2 and USART3 do not implement all the modem signals. Only RTS and
CTS (RTS0 and CTS0, RTS2 and CTS2, RTS3 and CTS3, respectively) are implemented in
these USARTs for other features.
Thus, programming the USART0, USART2 or the USART3 in Modem Mode may lead to unpredictable results. In these USARTs, the commands relating to the Modem Mode have no effect
and the status bits relating the status of the modem signals are never activated.
10.17 Serial Synchronous Controller
• Provides serial synchronous communication links used in audio and telecom applications
• Contains an independent receiver and transmitter and a common clock divider
• Interfaced with two PDC channels to reduce processor overhead
• Offers a configurable frame sync and data length
• Receiver and transmitter can be programmed to start automatically or on detection of
different event on the frame sync signal
• Receiver and transmitter include a data signal, a clock signal and a frame synchronization
signal
10.18 Timer Counter
• Three 16-bit Timer Counter Channels
• Wide range of functions including:
– Frequency Measurement
– Event Counting
31
1768I–ATARM–09-Jul-09
– 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
• The Timer Counter 0 to 5 are described with five generic clock inputs, TIMER_CLOCK1 to
TIMER_CLOCK5. In the AT91RM9200, these clock inputs are connected to the Master Clock
(MCK), to the Slow Clock (SLCK) and to divisions of the Master Clock. For details, see “Clock
Control” on page 488.
Table 10-6 gives the correspondence between the Timer Counter clock inputs and clocks in
the AT91RM9200. Each Timer Counter 0 to 5 displays the same configuration.
Table 10-6.
Timer Counter Clocks Assignment
TC Clock Input
Clock
TIMER_CLOCK1
MCK/2
TIMER_CLOCK2
MCK/8
TIMER_CLOCK3
MCK/32
TIMER_CLOCK4
MCK/128
TIMER_CLOCK5
SLCK
10.19 MultiMedia Card Interface
• Compatibility with MultiMedia Card Specification Version 2.2
• Compatibility with SD Memory Card Specification Version 1.0
• Cards clock rate up to Master Clock divided by 2
• Embedded power management to slow down clock rate when not used
• Supports two slots
– One slot for one MultiMedia Card bus (up to 30 cards) or one SD Memory Card
• Support for stream, block and multi-block data read and write
• Connection to a Peripheral DMA Controller (PDC) channel
– Minimizes processor intervention for large buffer transfers
32
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
11. ARM920T Processor Overview
11.1
Overview
The ARM920T cached processor is a member of the ARM9™ Thumb family of high-performance
32-bit system-on-a-chip processors. It provides a complete high performance CPU subsystem
including:
• ARM9TDMI RISC integer CPU
• 16-Kbyte instruction and 16-Kbyte data caches
• Instruction and data memory management units (MMUs)
• Write buffer
• AMBA™ (Advanced Microprocessor Bus Architecture) bus interface
• Embedded Trace Macrocell (ETM) interface
The ARM9TDMI core within the ARM920T executes both the 32-bit ARM and 16-bit Thumb
instruction sets. The ARM9TDMI processor is a Harvard architecture device, implementing a
five-stage pipeline consisting of Fetch, Decode, Execute, Memory and Write stages.
The ARM920T processor incorporates two coprocessors:
• CP14 - Controls software access to the debug communication channel
• CP15 - System Control Processor, providing 16 additional registers that are used to configure
and control the caches, the MMU, protection system, clocking mode and other system
options
The main features of the ARM920T processor are:
• ARM9TDMI-based, ARM Architecture v4T
• Two Instruction Sets
– ARM High-performance 32-bit Instruction Set
– Thumb High Code Density 16-bit Instruction Set
• 5-Stage Pipeline Architecture
– Instruction Fetch (F)
– Instruction Decode (D)
– Execute (E)
– Data Memory Access (M)
– Register Write (W)
• 16-Kbyte Data Cache, 16-Kbyte Instruction Cache
– Virtually-addressed 64-way Associative Cache
– 8 Words per Line
– Write-though and Write-back Operation
– Pseudo-random or Round-robin Replacement
– Low-power CAM RAM Implementation
• Write Buffer
– 16-word Data Buffer
– 4-address Address Buffer
– Software Control Drain
33
1768I–ATARM–09-Jul-09
• Standard ARMv4 Memory Management Unit (MMU)
– Access Permission for Sections
– Access Permission for Large Pages and Small Pages Can be Specified Separately
for Each Quarter of the Pages
– 16 Embedded Domains
– 64-entry Instruction TLB and 64-entry Data TLB
• 8-, 16-, 32-bit Data Bus for Instructions and Data
34
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
11.2
Block Diagram
Figure 11-1. ARM920T Internal Functional Block Diagram
ARM920T
Instruction
Cache
Instruction
MMU
Instruction
Physical
Address
Bus
Instruction
Modified
Virtual
Address
Bus
R13
Instruction
Virtual
Address
Bus
Instruction
Bus
ICE
Interface
ICE
ARM9TDMI
Data
Virtual
Address
Bus
Data
Bus
Data
Cache
Memory
Controller
Write
Buffer
Data
Modified
Virtual
Address
Bus
R13
Bus
Interface
CP15
Data
Physical
Address
Bus
Data
MMU
Data Index Bus
Write Back
PA TAG RAM
Write Back
Physical
Address
Bus
35
1768I–ATARM–09-Jul-09
11.3
ARM9TDMI Processor
11.3.1
Instruction Type
Instructions are either 32 bits (in ARM state) or 16 bits (in Thumb state).
11.3.2
Data Types
ARM9TDMI supports byte (8-bit), half-word (16-bit) and word (32-bit) data types. Words must be
aligned to four-byte boundaries and half-words to two-byte boundaries.
Unaligned data access behavior depends on which instruction is used in a particular location.
11.3.3
ARM9TDMI Operating Modes
The ARM9TDMI, based on ARM architecture v4T, supports seven processor modes:
• User: Standard ARM program execution state
• FIQ: Designed to support high-speed data transfer or channel processes
• IRQ: Used for general-purpose interrupt handling
• Supervisor: Protected mode for the operating system
• Abort mode: Implements virtual memory and/or memory protection
• System: A privileged user mode for the operating system
• Undefined: Supports software emulation of hardware coprocessors
Mode changes may be made under software control, or may be brought about by external interrupts or exception processing. Most application programs will execute in User Mode. The nonuser modes, known as privileged modes, are entered in order to service interrupts or exceptions
or to access protected resources.
11.3.4
ARM9TDMI Registers
The ARM9TDMI processor core consists of a 32-bit datapath and associated control logic. That
datapath contains 31 general-purpose registers, coupled to a full shifter, Arithmetic Logic Unit
and multiplier.
At any one time, 16 registers are visible to the user. The remainder are synonyms used to speed
up exception processing.
Register 15 is the Program Counter (PC) and can be used in all instructions to reference data
relative to the current instruction.
R14 holds the return address after a subroutine call.
R13 is used (by software convention) as a stack pointer.
Table 11-1.
36
ARM9TDMI Modes and Register Layout
User and
System
Mode
Supervisor
Mode
Abort Mode
Undefined
Mode
Interrupt
Mode
Fast
Interrupt
Mode
R0
R0
R0
R0
R0
R0
R1
R1
R1
R1
R1
R1
R2
R2
R2
R2
R2
R2
R3
R3
R3
R3
R3
R3
R4
R4
R4
R4
R4
R4
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table 11-1.
ARM9TDMI Modes and Register Layout (Continued)
User and
System
Mode
Supervisor
Mode
Abort Mode
Undefined
Mode
Interrupt
Mode
Fast
Interrupt
Mode
R5
R5
R5
R5
R5
R5
R6
R6
R6
R6
R6
R6
R7
R7
R7
R7
R7
R7
R8
R8
R8
R8
R8
R8_FIQ
R9
R9
R9
R9
R9
R9_FIQ
R10
R10
R10
R10
R10
R10_FIQ
R11
R11
R11
R11
R11
R11_FIQ
R12
R12
R12
R12
R12
R12_FIQ
R13
R13_SVC
R13_ABORT
R13_UNDEF
R13_IRQ
R13_FIQ
R14
R14_SVC
R14_ABORT
R14_UNDEF
R14_IRQ
R14_FIQ
PC
PC
PC
PC
PC
PC
CPSR
CPSR
CPSR
CPSR
CPSR
CPSR
SPSR_SVC
SPSR_ABO
RT
SPSR_UND
EF
SPSR_IRQ
SPSR_FIQ
Mode-specific banked
registers
Registers R0 to R7 are unbanked registers, thus each of them refers to the same 32-bit physical
register in all processor modes. They are general-purpose registers, with no special uses managed by the architecture, and can be used wherever an instruction allows a general-purpose
register to be specified.
Registers R8 to R14 are banked registers. This means that each of them depends of the current
processor mode.
For further details, see the ARM Architecture Reference Manual, Rev. DDI0100E.
11.3.4.1
Modes and Exception Handling
All exceptions have banked registers for R14 and R13.
After an exception, R14 holds the return address for exception processing. This address is used
both to return after the exception is processed and to address the instruction that caused the
exception.
R13 is banked across exception modes to provide each exception handler with a private stack
pointer.
The fast interrupt mode also banks registers 8 to 12 so that interrupt processing can begin without the need to save these registers.
37
1768I–ATARM–09-Jul-09
A seventh processing mode, System Mode, does not have any banked registers. It uses the
User Mode registers. System Mode runs tasks that require a privileged processor mode and
allows them to invoke all classes of exceptions.
11.3.4.2
Status Registers
All other processor states are held in status registers. The current operating processor status is
in the Current Program Status Register (CPSR). The CPSR holds:
• four ALU flags (Negative, Zero, Carry, and Overflow),
• two interrupt disable bits (one for each type of interrupt),
• one bit to indicate ARM or Thumb execution
• five bits to encode the current processor mode
All five exception modes also have a Saved Program Status Register (SPSR) which holds the
CPSR of the task immediately before the exception occurred.
11.3.4.3
Exception Types
The ARM9TDMI supports five types of exceptions and a privileged processing mode for each
type. The types of exceptions are:
• fast interrupt (FIQ)
• normal interrupt (IRQ)
• memory aborts (used to implement memory protection or virtual memory)
• attempted execution of an undefined instruction
• software interrupt (SWIs)
Exceptions are generated by internal and external sources.
More than one exception can occur at the same time.
When an exception occurs, the banked version of R14 and the SPSR for the exception mode
are used to save the state.
To return after handling the exception, the SPSR is moved to the CPSR and R14 is moved to the
PC. This can be done in two ways:
• use of a data-processing instruction with the S-bit set, and the PC as the destination
• use of the Load Multiple with Restore CPSR instruction (LDM)
11.3.5
ARM Instruction Set Overview
The ARM instruction set is divided into:
• Branch instructions
• Data processing instructions
• Status register transfer instructions
• Load and Store instructions
• Coprocessor instructions
• Exception-generating instructions
ARM instructions can be executed conditionally. Every instruction contains a 4-bit condition
code field (bits[31:28]).
For further details, see the ARM920T Technical Reference Manual, Rev. DDI0151C.
38
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table 11-2 gives the ARM instruction mnemonic list.
Table 11-2.
ARM Instruction Mnemonic List
Mnemonic
Operation
Mnemonic
Operation
MOV
Move
CDP
Coprocessor Data Processing
ADD
Add
MVN
Move Not
SUB
Subtract
ADC
Add with Carry
RSB
Reverse Subtract
SBC
Subtract with Carry
CMP
Compare
RSC
Reverse Subtract with Carry
TST
Test
CMN
Compare Negated
AND
Logical AND
TEQ
Test Equivalence
EOR
Logical Exclusive OR
BIC
Bit Clear
MUL
Multiply
ORR
Logical (inclusive) OR
SMULL
Sign Long Multiply
MLA
Multiply Accumulate
SMLAL
Signed Long Multiply Accumulate
UMULL
Unsigned Long Multiply
Move to Status Register
UMLAL
Unsigned Long Multiply Accumulate
MSR
B
Branch
BX
MRS
Branch and Exchange
LDR
BL
Move From Status Register
Branch and Link
Load Word
SWI
Software Interrupt
LDRSH
Load Signed Halfword
STR
Store Word
LDRSB
Load Signed Byte
STRH
Store Half Word
LDRH
Load Half Word
STRB
Store Byte
LDRB
Load Byte
LDRBT
STRBT
Store Register Byte with Translation
Load Register Byte with Translation
STRT
Store Register with Translation
LDRT
Load Register with Translation
STM
Store Multiple
LDM
Load Multiple
SWP
Swap Word
MRC
Move From Coprocessor
MCR
Move To Coprocessor
STC
Store From Coprocessor
LDC
Load To Coprocessor
11.3.6
SWPB
Swap Byte
Thumb Instruction Set Overview
The Thumb instruction set is a re-encoded subset of the ARM instruction set.
The Thumb instruction set is divided into:
• Branch instructions
• Data processing instructions
• Load and Store instructions
• Load and Store multiple instructions
• Exception-generating instruction
In Thumb mode, eight general-purpose registers are available, R0 to R7, that are the same
physical registers as R0 to R7 when executing ARM instructions. Some Thumb instructions also
access the Program Counter (ARM Register 15), the Link Register (ARM Register 14) and the
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1768I–ATARM–09-Jul-09
Stack Pointer (ARM Register 13). Further instructions allow limited access to the ARM register 8
to 15.
For further details, see the ARM920T Technical Reference Manual, Rev. DDI0151C.
Table 11-3 gives the Thumb instruction mnemonic list.
Table 11-3.
Mnemonic
Operation
Mnemonic
Move
ADD
Add
ADC
Add with Carry
SUB
Subtract
SBC
Subtract with Carry
CMP
Compare
CMN
Compare Negated
TST
Test
NEG
Negate
AND
Logical AND
BIC
Bit Clear
EOR
Logical Exclusive OR
ORR
Logical (inclusive) OR
LSL
Logical Shift Left
LSR
Logical Shift Right
ASR
Arithmetic Shift Right
ROR
Rotate Right
MUL
Multiply
B
Branch
LDR
MVN
Operation
MOV
BX
40
Thumb Instruction Mnemonic List
Move Not
BL
Branch and Link
Branch and Exchange
SWI
Software Interrupt
Load Word
STR
Store Word
LDRH
Load Half Word
STRH
Store Half Word
LDRB
Load Byte
STRB
Store Byte
LDRSH
Load Signed Halfword
LDRSB
Load Signed Byte
LDMIA
Load Multiple
STMIA
Store Multiple
PUSH
Push Register to stack
POP
Pop Register from stack
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11.4
CP15 Coprocessor
Coprocessor 15, or System Control Coprocessor CP15, is used when special features are used
with the ARM9TDMI such as:
• On-chip Memory Management Unit (MMU)
• Instruction and/or Data Cache
• Write buffer
To control these features, CP15 provides 16 additional registers. See Table 11-4.
Table 11-4.
CP15 Registers
Register
Notes:
Name
Access
0
ID Register
Read-only
1
Control
Read/Write
2
Translation Table Base
Read/Write
3
Domain Access Control
Read/Write
4
Reserved
None
5
Fault Status
Read/Write
6
Fault Address
Read/Write
7
Cache Operations
Write-only
(1)
Operations
Write-only
8
TLB
9
cache lockdown
Read/Write
10
TLB lockdown
Read/Write
11
Reserved
None
12
Reserved
None
13
FCSE PID(2)
Read/Write
14
Reserved
None
15
Test configuration
None
1. TLB: Translation Lookaside Buffer
2. FCSE PID: Fast Context Switch Extension Process Identifier
11.4.1
CP15 Register Access
CP15 registers can only be accessed in privileged mode by:
• MCR (Move to Coprocessor from ARM Register) instruction
• MRC (Move to ARM Register from Coprocessor) instruction
Other instructions (CDP, LDC, STC) cause an undefined instruction exception.
The MCR instruction is used to write an ARM register to CP15.
The MRC instruction is used to read the value of CP15 to an ARM register.
The assembler code for these instructions is:
MCR/MRC{cond} p15, opcode_1, Rd, CRn, CRm, opcode_2.
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1768I–ATARM–09-Jul-09
The MCR, MRC instructions bit pattern is shown below:
31
30
29
28
Cond
23
22
21
opcode_1
15
20
26
25
24
1
1
1
0
19
18
17
16
L
14
13
12
Rd
7
27
6
5
opcode_2
4
CRn
11
10
9
8
1
1
1
1
3
2
1
0
1
CRm
• CRm[3:0]: Specified Coprocessor Action
Determines specific coprocessor action. Its value is dependent on the CP15 register used. For details, refer to CP15 specific register behavior.
• opcode_2[7:5]
Determines specific coprocessor operation code. By default, set to 0.
• Rd[15:12]: ARM Register
Defines the ARM register whose value is transferred to the coprocessor. If R15 is chosen, the result is unpredictable.
• CRn[19:16]: Coprocessor Register
Determines the destination coprocessor register.
• opcode_1[23:20]: Coprocessor Code
Defines the coprocessor specific code. Value is c15 for CP15.
• L: Instruction Bit
0 = MCR instruction
1 = MRC instruction
• Cond [31:28]: Condition
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11.5
Memory Management Unit (MMU)
The ARM920T processor implements an enhanced ARM architecture v4 MMU to provide translation and access permission checks for the instruction and data address ports of the
ARM9TDMI core. The MMU is controlled from a single set of two-level page tables stored in the
main memory, providing a single address and translation protection scheme. Independently,
instruction and data TLBs in the MMU can be locked and flushed.
Table 11-5.
11.5.1
Mapping Details
Mapping Name
Mapping Size
Access Permission By
Subpage Size
Section
1M byte
Section
-
Large Page
64K bytes
4 separated subpages
16K bytes
Small Page
4K bytes
4 separated subpages
1K byte
Tiny Page
1K byte
Tiny Page
-
Domain
A domain is a collection of sections and pages. The ARM920T supports 16 domains. Access to
the domains is controlled by the Domain Access Control register. For details, refer to “CP15
Register 3, Domain Access Control Register” on page 50.
11.5.2
MMU Faults
The MMU generates alignment faults, translation faults, domain faults and permission faults.
Alignment fault checking is not affected by whether the MMU is enabled or not.
The access controls of the MMU detect the conditions that produce these faults. If the fault is a
result of memory access, the MMU aborts the access and signals the fault to the CPU core.The
MMU stores the status and address fault in the FSR and FAR registers (only for faults generated
by data access).
The MMU does not store fault information about faults generated by an instruction fetch.
The memory system can abort during line fetches, memory accesses and translation table
access.
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1768I–ATARM–09-Jul-09
11.6
Caches, Write Buffers and Physical Address
The ARM920T includes an Instruction Cache (ICache), a Data Cache (DCache), a write buffer
and a Physical Address (PA) TAG RAM to reduce the effect on main memory bandwidth and
latency performance.
The ARM920T implements separate 16-Kbyte Instruction and 16-Kbyte Data Caches.
The caches and the write buffer are controlled by the CP15 Register 1 (Control), CP15 Register
7 (Cache Operations) and CP15 Register 9 (Cache Lockdown).
11.6.1
Instruction Cache (ICache)
The ARM920T includes a 16-Kbyte Instruction Cache (ICache). The ICache has 512 lines of 32
bytes, arranged as a 64-way set associative cache.
Instruction access is subject to MMU permission and translation checks.
If the ICache is enabled with the MMU disabled, all instructions fetched as threats are cachable.
No protection checks are made and the physical address is flat-mapped to the modified virtual
address.
When the ICache is disabled, the cache contents are ignored and all instruction fetches appear
on the AMBA bus.
On reset, the ICache entries are invalidated and the ICache is disabled. For best performance,
ICache should be enabled as soon as possible after reset.
The ICache is enabled by writing 1 to I bit of the CP15 Register 1 and disabled by writing 0 to
this bit. For more details, see “CP15 Register 1, Control” on page 48.
The ICache is organized as eight segments, each containing 64 lines with each line made up of
8 words.The position of the line within the segment is called the index and is numbered from 0 to
63.
A line in the cache is identified by the index and segment. The index is independent of the MVA
(Modified Virtual Address), and the segment is the bit[7:5] of the MVA.
11.6.2
11.6.2.1
Data Cache (DCache) and Write Buffer
The ARM920T includes a 16-Kbyte data cache (DCache). The DCache has 512 lines of 32
bytes, arranged as a 64-way set associative cache, and uses MVAs translated by CP15 Register 13 from the ARM9DTMI core.
DCache
The DCache is organized as eight segments, each containing 64 lines with each line made up of
eight words.The position of the line within the segment is called the index and is a number from
0 to 63.
The Write Buffer can hold up to 16 words of data and four separate addresses.
DCache and Write Buffer operations are closely connected as their configuration is set in each
section by the page descriptor in the MMU translation table.
All data accesses are subject to MMU permission and translation checks. Data accesses
aborted by the MMU cannot cause linefill or data access via the AMBA ASB interface.
Write-though Operation
44
When a cache hit occurs for a data access, the cache line that contains the data is updated to
contains its value. The new data is also immediately written to the main memory.
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Write-back Operation
11.6.2.2
When a cache hit occurs for a data access, the cache line is marked as dirty, meaning that its
contents are not up-to-date with those in the main memory.
Write Buffer
The ARM920T incorporates a 16-entry write buffer to avoid stalling the processor when writes to
external memory are performed. When a store occurs, its data, address and other details are
written to the write buffer at high speed. The write buffer then completes the store at the main
memory speed (typically slower than the ARM speed). In parallel, the ARM9TDMI processor can
execute further instructions at full speed.
11.6.2.3
Physical Address Tag RAM (PA TAG RAM)
The ARM920T implements Physical Address Tag RAM (PA TAG RAM) to perform write-backs
from the data cache. The physical address of all the lines held in the data cache is stored in the
PA TAG memory, removing the need for address translation when evicting a line from the cache.
When a line is written into the data cache, the physical address TAG is written into the PA TAG
RAM. If this line has to be written back to the main memory, the PA TAG RAM is read and the
physical address is used by the AMBA ASB interface to perform the write-back.
For a 16-Kbyte DCache, the PA TAG RAM is organized by eight segments with:
• 64 rows per segments
• 26 bits per rows
• be
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1768I–ATARM–09-Jul-09
11.7
ARM920T User Interface
11.7.1
CP15 Register 0, ID Code and Cache Type
Access: Read-only
The CP Register 0 contains specific hardware information. The contents of the read accesses are determined by the
opcode_2 field value. Writing to Register 0 is unpredictable.
11.7.1.1
ID Code
The ID code register is accessed by reading the register 0 with the opcode_2 field set to 0.
The contents of the ID code is shown below:
31
30
29
28
27
26
19
18
25
24
17
16
9
8
1
0
imp
23
22
21
20
SRev
15
14
archi
13
12
11
10
3
2
PNumber
7
6
5
4
Layout Rev
• LayoutRev[3:0]: Revision
Contains the processor revision number
• PNumber[15:4]: Processor Part Number
0x920 value for ARM920T processor.
• archi[19:16]: Architecture
Details the implementor architecture code.
0x2 value means ARMv4T architecture.
• SRev[23:20]: Specification Revision Number
0x1 value; specification revision number used to distinguished two variants of the same primary part.
• imp[31:24]: Implementor Code
0x41 (= A); means ARM Ltd.
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11.7.1.2
Cache Type
The Cache Type register is accessed by reading the register 0 with the opcode_2 field set to 1.
The Cache Type register contains information about the size and architecture of the caches.
31
30
29
0
0
0
23
22
21
28
27
26
25
ctype
20
24
S
19
18
17
16
11
10
9
8
3
2
1
0
DSize
15
14
13
12
7
6
5
4
ISize
• ISize[11:0]: Instruction Cache Size
Indicates the size, line length and associativity of the instruction cache.
• DSize[23:12]: Data Cache Size
Indicates the size, line length and associativity of the data cache.
• S[24]: Cache
Indicates if the cache is unified or has separate instruction and data caches.
Set to 1, this field indicates separate Instruction and Data caches.
• ctype[28:25]: Cache Type
Defines the cache type.
For details on bits DSize and ISize, refer to the ARM920T Technical Reference Manual, Rev. DDI0151C.
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1768I–ATARM–09-Jul-09
11.7.2
CP15 Register 1, Control
Access: Read/Write
The CP15 Register 1, or Control Register, contains the control bits of the ARM920T.
31
30
29
28
27
26
25
24
iA
nF
-
-
-
-
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
RR
V
I
0
0
R
S
7
6
5
4
3
2
1
0
B
1
1
1
1
C
A
M
• M[0]: MMU Enable
0 = MMU disabled.
1 = MMU enabled.
• A[1]: Alignment Fault Enable
0 = Fault checking disabled.
1 = Fault checking enabled.
• C[2]: DCache Enable
0 = DCache disabled.
1 = DCache enabled.
• B[7]: Endianness
0 = Little endian mode.
1 = Big endian mode.
• S[8]: System Protection
Modifies the MMU protection system.
For further details, see the ARM920T Technical Reference Manual, Rev. DDI0151C.
• R[9]: ROM Protection
Modifies the MMU protection system.
For further details, see the ARM920T Technical Reference Manual, Rev. DDI0151C.
• I[12]: ICache Control
0 = ICache disabled.
1 = ICache enabled.
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• V[13]: Base Location of Exception Register
0 = Low address means 0x00000000.
1 = High address means 0xFFFF0000.
• RR[14]: Round Robin Replacement
0 = Random replacement.
1 = Round robin replacement.
• Clocking Mode[31:30] (iA and nF bits)
iA
nF
Clocking mode
0
0
Fast Bus
0
1
Synchronous
1
0
Reserved
1
1
Asynchronous
11.7.3
CP15 Register 2, TTB
Access: Read/Write
The CP15 Register 2, or Translation Table Base (TTB) Register, defines the first-level translation table.
31
30
29
28
27
26
25
24
19
18
17
16
Pointer
23
22
21
20
Pointer
15
14
Pointer
13
12
11
10
9
8
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
-
• Pointer[31:14]
Points to the first-level translation table base. Read returns the currently active first-level translation table. Write sets the
pointer to the first-level table to the written value.
The non-defined bits should be zero when written and are unpredictable when read.
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1768I–ATARM–09-Jul-09
11.7.4
CP15 Register 3, Domain Access Control Register
Access: Read/Write
The CP 15 Register 3, or Domain Access Control Register, defines the domain’s access permission.
MMU accesses are priory controlled through the use of 16 domains.
Each field of Register 3 is associated with one domain.
31
30
29
D15
23
28
27
D14
22
21
D11
26
25
D13
20
19
D10
24
D12
18
17
D9
16
D8
D
15
14
13
D7
7
12
11
D6
6
5
D3
10
9
D5
4
3
D2
8
D4
2
D1
1
0
D0
• D15 to D0: Named Domain Access
The 2-bit field value allows domain access as described in the table below.
Value
Access
Description
0
0
No access
Any access generates a domain fault
0
1
Client
The Users of domain (execute programs, access data), the domain access
permission controlled the domain access.
1
0
Reserved
Reserved
1
1
Manager
Controls the behavior of the domain, no checking of the domain access
permission is done
11.7.5
CP15 Register 4, Reserved
Any access (Read or Write) to this register causes unpredictable behavior.
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11.7.6
CP15 Register 5, Fault Status Register
Access: Read/Write
Reading the CP 15 Register 5, or Fault Status Register (FSR), returns the source of the last data fault, indicating the
domain and type of access being attempted when the data abort occurred.
In addition, the virtual address which caused the data abort is written into the Fault Address Register (CP15 Register 6).
Writing the CP 15 Register 5, or Fault Status Register (FSR), sets the FSR to the value of the data written. This is useful for
a debugger to restore the value of the FSR.
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
D
Domain
Status
• Status[3:0]: Fault Type
Indicates the fault type. The status field is encoded by the MMU when a data abort occurs. The interpretation of the Status
field is dependant on the domain field and the MVA associated with the data abort (stored in the FAR).
• Domain[7:4]: Domain
Indicates the domain (D15 - D0) being accessed when the fault occurred.
The non-defined bits should be zero when written and are unpredictable when read.
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1768I–ATARM–09-Jul-09
11.7.7
CP15 Register 6, Fault Address Register
Access: Read/Write
The CP 15 Register 6, or Fault Address Register (FAR), contains the MVA (Modified Virtual Address) of the access being
attempted when the last fault occurred. The FAR is only updated for data faults, not for prefetch faults.
The ability to write to the FAR is provided to allow a debugger to restore a previous state.
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
FAR
23
22
21
20
FAR
D
15
14
13
12
FAR
7
6
5
4
FAR
• FAR[31:0]: Fault Address
On reading: returns the value of the FAR. The FAR holds the virtual address of the access which was attempted when fault
occurred.
On writing: sets the FAR to the value of the written data. This is useful for a debugger to restore the value of the FAR.
11.7.8
CP15 Register 7, Cache Operation Register
Access: Write-only
The CP15 Register 7, or Cache Operation Register, is used to manage the Instruction Cache (ICache) and the Data Cache
(DCache).
The function of each cache operation is selected by the opcode_2 and CRm fields in the MCR instruction used to write
CP15 Register 7.
Table 11-6.
Cache Functions
Function
Data
CRm
opcode_2
Wait for Interrupt
SBZ
c0
4
Invalidate ICache
SBZ
c5
0
Invalidate ICache single entry (using MVA)
MVA format
c5
1
Invalidate DCache
SBZ
c6
0
Invalidate DCache single entry (using MVA)
MVA format
c6
1
Invalidate ICache and DCache
SBZ
c7
0
Clean DCache singe entry (using MVA)
MVA format
c10
1
Clean DCache single entry (using index)
Index format
c10
2
Drain write buffer
SBZ
c10
4
Prefetch ICache line (using MVA)
MVA format
c13
1
Clean and Invalidate DCache entry (using MVA)
MVA format
c14
1
Clean and Invalidate DCache entry (using index)
Index format
c14
2
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Function Details
• Wait for interrupt
Stops execution in low-power state until an interrupt occurs.
• Invalidate
The cache line (or lines) is marked as invalid, so no cache hits occur in that line until it is re-allocated to an address.
• Clean
Applies to write-back data caches. If the cache line contains stored data that has not yet been written out to the main memory, it is written to main memory immediately.
• Drain write buffer
Stops the execution until all data in the write buffer has been stored in the main memory.
• Prefetch
The memory cache line at the specified virtual address is loaded into the cache.
The operation carried out on a single cache line identifies the line using the data transferred in the MCR instruction.
The data is interpreted as using one of the two formats:
– MVA format
– index format
Below are the details of CP15 Register 7, or Cache Function Register, in MVA format.
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
4
3
2
1
0
-
-
-
-
-
mva
23
22
21
20
mva
15
14
13
12
mva
7
6
mva
5
• mva[31:5]: Modified Virtual Address
The non-defined bits should be zero when written and are unpredictable when read.
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1768I–ATARM–09-Jul-09
Below the details of CP15 Register 7, or Cache Function Register, in Index format:
31
30
29
28
27
26
index
25
24
-
-
23
22
21
20
19
18
17
16
-
-
-
-
-
-
-
-
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
6
5
4
3
2
1
0
-
-
-
-
-
7
set
• index[31:26]: Line
Determines the cache line.
• set[7:5]: Segment
Determines the cache segment.
The non-defined bits should be zero when written and are unpredictable when read.
Writing other opcode_2 values or CRm values is unpredictable.
Reading from CP15 Register 7 is unpredictable.
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11.7.9
CP15 Register 8, TLB Operations Register
Access: Write-only
The CP15 Register 8, or Translation Lookaside Buffer (TLB) Operations Register, is used to manage instruction TLBs and
data TLBs.
The TLB operation is selected by opcode_2 and CRm fields in the MCR instruction used to write CP15 Register 8.
Table 11-7.
TLB Operations
Function
Data
CRm
opcode_2
Invalidate I TLB
SBZ
5
0
MVA format
5
1
SBZ
6
0
Invalidate D TLB single entry (using MVA)
MVA format
6
1
Invalidate both Instruction and Data TLB
SBZ
7
Invalidate I TLB single entry (using MVA)
Invalidate D TLB
Below are details of the CP15 Register 8 for TLB operation on MVA format and one single entry.
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
-
-
mva
23
22
21
20
mva
15
14
13
12
mva
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
-
• mva[31:10]: Modified Virtual Address
The non-defined bits should be zero when written and are unpredictable when read.
Writing other opcode_2 values or CRm values is unpredictable.
Reading from CP15 Register 8 is unpredictable.
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1768I–ATARM–09-Jul-09
11.7.10 CP15 Register 9, Cache Lockdown Register
Access: Read/Write
The CP15 Register 9, or Cache Lockdown Register, is 0x0 on reset. The Cache Lockdown Register allows software to control which cache line in the ICache or DCache is loaded for a linefill. It prevents lines in the ICache or DCache from being
evicted during a linefill, locking them into the cache.
Reading from the CP15 Register 9 returns the value of the Cache Lockdown Register that is the base pointer for all cache
segments.
Only the bits[31:26] are returned; others are unpredictable.
Writing to the CP15 Register 9 updates the Cache Lockdown Register with both the base and the current victim pointers for
all cache segments.
Table 11-8.
Cache Lockdown Functions
Function
Data
CRm
opcode_2
Read DCache lockdown base
Base
0
0
Victim = Base
0
0
Base
0
1
Victim = Base
0
1
Write DCache victim and lockdown base
Read ICache lockdown base
Write ICache victim and lockdown base
31
30
29
28
27
26
index
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
-
-
-
-
-
-
-
-
• index[31:26]: Victim Pointer
Current victim pointer that specifies the cache line to be used as victim for the next linefill.
The non-defined bits should be zero when written and are unpredictable when read.
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11.7.11 CP15 Register 10, TLB Lockdown Register
Access: Read/Write
The CP15 Register 10, or TLB Lockdown Register, is 0x0 on reset. There is a TLSB Lockdown Register for each of the
TLBs; the value of opcode_2 determines which TLB register to access:
• opcode_2 = 0x0 for D TLB register
• opcode_2 = 0x1 for I TLB register
Table 11-9.
TLB Lockdown Functions
Function
Data
CRm
Opcode_2
Read D TLB lockdown
TLB lockdown
0
0
Write D TLB lockdown
TLB lockdown
0
0
Read I TLB lockdown
TLB lockdown
0
1
Write I TLB lockdown
TLB lockdown
0
1
31
30
29
28
27
26
25
24
20
19
18
17
16
-
-
-
-
Base
23
22
21
Victim
D
15
14
13
12
11
10
9
8
-
-
-
-
-
-
-
-
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
P
• Base[31:26]: Base
The TLB replacement strategy only uses the TLB entries numbered from base to 63. The Victim field provided is in that
range.
• Victim[25:20]: Victim Counter
Specifies the TLB entry (line) being overwritten.
• P[0]: Preserved
If 0, the TLB entry can be invalidated.
If 1, the TLB entry is protected. It cannot be invalidated during the Invalidate All instruction. Refer to “CP15 Register 8, TLB
Operations Register” on page 55.
The non-defined bits should be zero when written and are unpredictable when read.
11.7.12 CP15 Registers 11, 12, Reserved
Any access (Read or Write) to these registers causes unpredictable behavior.
57
1768I–ATARM–09-Jul-09
11.7.13 CP15 Register 13, FCSE PID Register
Access: Read/Write
The CP15 Register 13, or Fast Context Switch Extension (FCSE) Process Identifier (PID) Register, is set to 0x0 on reset.
Reading from CP15 Register 13 returns the FCSE PID value.
Writing to CP15 Register 13 sets the FCSE PID.
The FCSE PID sets the mapping between the ARM9TDMI and the MMU of the cache memories.
The addresses issued by the ARM9TDMI are in the range of 0 to 32 Mbytes and are translated via the FCSE PID.
31
30
29
28
27
26
25
FCSEPID
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
-
-
-
-
-
-
-
-
D
• FCSEPID[31:25]: FCSE PID
The FCSE PID modifies the behavior of the of the ARM920T memory system. This modification allows multiple programs to
run on the ARM.
The 4-GB virtual address is divided into 128 process blocks of 32 Mbytes each. Each process block can contain a program
that has been compiled to use the address range 0x00000000 to 0x01FFFFFF. For each i = 0 to 127 process blocks, i runs
from address i*0x20000000 to address i*0x20000000 + 0x01FFFFFF.
For further details, see the ARM920T Technical Reference Manual, Rev. DDI0151C.
The non-defined bits should be zero when written and are unpredictable when read.
11.7.14 CP15 Register 14, Reserved
Any access (Read or Write) of these registers causes unpredictable behavior.
11.7.15 CP15 Register 15, Test Configuration Register
CP15 Register 15, or Test Configuration Register, is used for test purposed. Any access (write or read) to this register
causes unpredictable behavior.
58
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
12. Debug and Test Features (DBG Test)
12.1
Overview
The AT91RM9200 features a number of complementary debug and test capabilities. A common
JTAG/ICE (In-Circuit Emulator) port is used for standard debugging functions such as downloading code and single-stepping through programs. An ETM (Embedded Trace Macrocell) provides
more sophisticated debug features such as address and data comparators, half-rate clock
mode, counters, sequencer and FIFO. The Debug Unit provides a two-pin UART that can be
used to upload an application into internal SRAM. It manages the interrupt handling of the internal COMMTX and COMMRX signals that trace the activity of the Debug Communication
Channel.
A set of dedicated debug and test input/output pins give direct access to these capabilities from
a PC-based test environment.
Features of Debug and Test Features are:
• Integrated Embedded In-Circuit-Emulator
• Debug Unit
– Two-pin UART
– Debug Communication Channel
– Chip ID Register
• Embedded Trace Macrocell: ETM9 Rev2a
– Medium Level Implementation
– Half-rate Clock Mode
– Four Pairs of Address Comparators
– Two Data Comparators
– Eight Memory Map Decoder Inputs
– Two Counters
– One Sequencer
– One 18-byte FIFO
• IEEE1149.1 JTAG Boundary Scan on all Digital Pins
59
1768I–ATARM–09-Jul-09
12.2
Block Diagram
Figure 12-1. AT91RM9200 Debug and Test Block Diagram
TMS
TCK
TDI
NTRST
ICE/JTAG
TAP
Boundary
Port
JTAGSEL
TDO
ARM9TDMI
ICE
PIO
TPK0-TPK15
ETM
TPS0-TPS2
TSYNC
2
TCLK
ARM920T
DTXD
PDC
DBGU
DRXD
Reset
and
Test
TST0-TST1
NRST
TAP: Test Access Port
60
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
12.3
12.3.1
Application Examples
Debug Environment
Figure 12-2 on page 61 shows a complete debug environment example. The ICE/JTAG interface is used for standard debugging functions such as downloading code and single-stepping
through the program. The Trace Port interface is used for tracing information. A software debugger running on a personal computer provides the user interface for configuring a Trace Port
interface utilizing the ICE/JTAG interface.
Figure 12-2. AT91RM9200-based Application Debug and Trace Environment Example
Host Debugger
ICE/JTAG
Interface
ICE/JTAG
Connector
Trace Port
Interface
Trace
Connector
AT91RM9200
RS232
Connector
Terminal
AT91RM9200-based Application Board
12.4
Test Environment
Figure 12-3 below shows a test environment example. Test vectors are sent and interpreted by
the tester. In this example, the “board under test” is designed using many JTAG compliant
devices. These devices can be connected together to form a single scan chain.
61
1768I–ATARM–09-Jul-09
Figure 12-3. AT91RM9200-based Application IEEE1149.1 Test Environment Example
Test Adaptor
Tester
JTAG
Interface
ICE/JTAG
Connector
Chip n
AT91RM920
Chip 2
Chip 1
AT91RM9200-based Application Board Under Test
12.5
Debug and Test Pin Description
Table 12-1.
Debug and Test Pin List
Pin Name
Function
Type
Active Level
Low
Reset/Test
NRST
Microcontroller Reset
Input
TST0
Test Mode Select
Input
TST1
Test Mode Select
Input
ICE and JTAG
TCK
Test Clock
Input
TDI
Test Data In
Input
TDO
Test Data Out
TMS
Test Mode Select
Input
NTRST
Test Reset Signal
Input
JTAGSEL
JTAG Selection
Input
Output
Low
ETM (available only in BGA package)
TSYNC
Trace Synchronization Signal
Output
TCLK
Trace Clock
Output
TPS0- TPS2
Trace ARM Pipeline Status
Output
TPK0 - TPK15
Trace Packet Port
Output
Debug Unit
DRXD
Debug Receive Data
Input
DRXD
DTXD
Debug Transmit Data
Output
DTXD
62
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
12.6
Functional Description
12.6.1
Test Mode Pins
Two dedicated pins (TST1, TST0) are used to define the test mode of the device. The user must
make sure that these pins are both tied at low level to ensure normal operating conditions. Other
values associated to these pins are manufacturing test reserved.
12.6.2
Embedded In-Circuit Emulator
The ARM9TDMI Embedded In-Circuit Emulator is supported via the ICE/JTAG port. It is connected to a host computer via an ICE interface. Debug support is implemented using an
ARM9TDMI core embedded within the ARM920T. The internal state of the ARM920T is examined through an ICE/JTAG port which allows instructions to be serially inserted into the pipeline
of the core without using the external data bus. Therefore, when in debug state, a store-multiple
(STM) can be inserted into the instruction pipeline. This exports the contents of the ARM9TDMI
registers. This data can be serially shifted out without affecting the rest of the system.
There are six scan chains inside the ARM920T processor which support testing, debugging, and
programming of the Embedded ICE. The scan chains are controlled by the ICE/JTAG port.
Embedded ICE mode is selected when JTAGSEL is low. It is not possible to switch directly
between ICE and JTAG operations. A chip reset must be performed (NRST and NTRST) after
JTAGSEL is changed. The test reset input to the embedded ICE (NTRST) is provided separately
to facilitate debug of the boot program.
For further details on the Embedded In-Circuit-Emulator, see the ARM920T Technical Reference Manual, ARM Ltd, - DDI 0151C.
12.6.3
Debug Unit
The Debug Unit provides a two-pin (DXRD and TXRD) UART that can be used for several
debug and trace purposes and offers an ideal means for in-situ programming solutions and
debug monitor communication. Moreover, the link with two Peripheral DMA Controller channels
provides packet handling of these tasks with processor time reduced to a minimum.
The Debug Unit also manages the interrupt handling of the COMMTX and COMMRX signals
that come from the ICE and trace the activity of the Debug Communication Channel.
The Debug Unit can be used to upload an application into internal SRAM. It is activated by the
boot program when no valid application is detected.
A specific register, the Debug Unit Chip ID Register, informs about the product version and its
internal configuration.
The AT91RM9200 Debug Unit Chip ID value is: 0x09290781, on 32-bit width.
For further details on the Debug Unit, see “Debug Unit (DBGU)” on page 321.
For further details on the Debug Unit and the Boot program, see “Boot Program” on page 83.
12.6.4
Embedded Trace Macrocell
The AT91RM9200 features an Embedded Trace Macrocell (ETM), which is closely connected to
the ARM9TDMI Processor. The Embedded Trace is a standard mid-level implementation and
contains the following resources:
• Four pairs of address comparators
• Two data comparators
63
1768I–ATARM–09-Jul-09
• Eight memory map decoder inputs
• Two counters
• One sequencer
• Four external inputs
• One external output
• One 18-byte FIFO
The Embedded Trace Macrocell of the AT91RM9200 works in half-rate clock mode and thus
integrates a clock divider. This assures that the maximum frequency of all the trace port signals
do not exceed one half of the ARM920T clock speed.
The Embedded Trace Macrocell input and output resources are not used in the AT91RM9200.
The Embedded Trace is a real-time trace module with the capability of tracing the ARM9TDMI
instruction and data.
The Embedded Trace debug features are only accessible in the AT91RM9200 BGA package.
For further details on Embedded Trace Macrocell, see the ETM9 (Rev2a) Technical Reference
Manual, ARM Ltd. -DDI 0157E.
12.6.4.1
Trace Port
The Trace Port is made up of the following pins:
• TSYNC - the synchronization signal (Indicates the start of a branch sequence on the trace
packet port.)
• TCLK - the Trace Port clock, half-rate of the ARM920T processor clock.
• TPS0 to TPS2 - indicate the processor state at each trace clock edge.
• TPK0 to TPK15 - the Trace Packet data value.
The trace packet information (address, data) is associated with the processor state indicated by
TPS. Some processor states have no additional data associated with the Trace Packet Port (i.e.
failed condition code of an instruction). The packet is 8-bits wide, and up to two packets can be
output per cycle.
64
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Figure 12-4. ETM9 Block
TPS-TPS0
ARM920T
Bus Tracker
Trace
Control
FIFO
TPK15-TPK0
TSYNC
Trace Enable, View Data
TAP
Controller
Trigger, Sequencer, Counters
Scan Chain 6
12.6.4.2
TDO
TDI
TMS
TCK
ETM9
Implementation Details
This section gives an overview of the Embedded Trace resources. For further details, see the
Embedded Trace Macrocell Specification, ARM Ltd. -IHI 0014H.
Three-state Sequencer
The sequencer has three possible next states (one dedicated to itself and two others) and can
change on every clock cycle. The sate transition is controlled with internal events. If the user
needs multiple-stage trigger schemes, the trigger event is based on a sequencer state.
Address Comparator
In single mode, address comparators compare either the instruction address or the data address
against the user-programmed address.
In range mode, the address comparators are arranged in pairs to form a virtual address range
resource.
Details of the address comparator programming are:
• The first comparator is programmed with the range start address.
• The second comparator is programmed with the range end address.
• The resource matches if the address is within the following range:
– (address > = range start address) AND (address < range end address)
• Unpredictable behavior occurs if the two address comparators are not configured in the same
way.
Data Comparator
Each full address comparator is associated with a specific data comparator. A data comparator
is used to observe the data bus only when load and store operations occur.
A data comparator has both a value register and a mask register, therefore it is possible to compare only certain bits of a preprogrammed value against the data bus.
65
1768I–ATARM–09-Jul-09
Memory Decoder Inputs
The eight memory map decoder inputs are connected to custom address decoders. The
address decoders divide the memory into regions of on-chip SRAM, on-chip ROM, and peripherals. The address decoders also optimize the ETM9 trace trigger.
Table 12-2.
ETM Memory Map Inputs Layout
Description
Region
Access type
start_address
end_address
SRAM
Internal
Data
0x00000000
0x000FFFFF
SRAM
Internal
Fetch
0x00000000
0x000FFFFF
ROM
Internal
Data
0x00100000
0x001FFFFF
ROM
Internal
Fetch
0x00100000
0x001FFFFF
NCS0-NCS7
External
Data
0x10000000
0x8FFFFFFF
NCS0-NCS7
External
Fetch
0x10000000
0x8FFFFFFF
User Peripheral
Internal
Data
0xF0000000
0xFFFFEFFF
System
Peripheral
Internal
Data
0xFFFFF000
0xFFFFFFFF
FIFO
An 18-byte FIFO is used to store data tracing. The FIFO is used to separate the pipeline status
from the trace packet. So, the FIFO can be used to buffer trace packets.
A FIFO overflow is detected by the embedded trace macrocell when the FIFO is full or when the
FIFO has less bytes than the user-programmed number.
For further details, see the ETM9 (Rev2a) Technical Reference Manual, ARM Ltd. DDI 0157E.
Half-rate Clocking Mode
The ETM9 is implemented in half-rate mode that allows both rising and falling edge data tracing
of the trace clock.
The half-rate mode is implemented to maintain the signal clock integrity of high speed systems
(up to 100 Mhz).
Figure 12-5.
Half-rate Clocking Mode
ARM920T Clock
Trace Clock
TraceData
Half-rate Clocking Mode
Care must be taken on the choice of the trace capture system as it needs to support half-rate
clock functionality.
66
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
12.6.4.3
Application Board Restriction
The TCLK signal needs to be set with care, some timing parameters are required.
Refer to AT91RM9200 “JTAG/ICE Timings” on page 657 and “ETM Timings” on page 660.
The specified target system connector is the AMP Mictor connector.
The connector must be oriented on the application board as described below in Figure 12-6. The
view of the PCB is shown from above with the trace connector mounted near the edge of the
board. This allows the Trace Port Analyzer to minimize the physical intrusiveness of the interconnected target.
Figure 12-6. AMP Mictor Connector Orientation
AT91RM9200-based
Application Board
38 37
2
1
Pin 1Chamfer
12.6.5
IEEE 1149.1 JTAG Boundary Scan
IEEE 1149.1 JTAG Boundary Scan allows pin-level access independent of the device packaging
technology.
IEEE 1149.1 JTAG Boundary Scan is enabled when JTAGSEL is high. The SAMPLE, EXTEST
and BYPASS functions are implemented. In ICE debug mode, the ARM processor responds
with a non-JTAG chip ID that identifies the processor to the ICE system. This is not IEEE 1149.1
JTAG-compliant.
It is not possible to switch directly between JTAG and ICE operations. A chip reset must be performed (NRST and NTRST) after JTAGSEL is changed.
Two Boundary Scan Descriptor Language (BSDL) files are provided to set up testing. Each
BSDL file is dedicated to a specific packaging.
12.6.5.1
JTAG Boundary Scan Register
The Boundary Scan Register (BSR) contains 449 bits which correspond to active pins and associated control signals.
Each AT91RM9200 input pin has a corresponding bit in the Boundary Scan Register for
observability.
Each AT91RM9200 output pin has a corresponding 2-bit register in the BSR. The OUTPUT bit
contains data which can be forced on the pad. The CTRL bit can put the pad into high
impedance.
67
1768I–ATARM–09-Jul-09
Each AT91RM9200 input/output pin corresponds to a 3-bit register in the BSR. The OUTPUT
bit contains data that can be forced on the pad. The INPUT bit facilitates the observability of data
applied to the pad. The CTRL bit selects the direction of the pad.
Table 12-3.
JTAG Boundary Scan Register
Bit
Number
Pin Name
Pin Type
Associated BSR
Cells
449
A19
Output
OUTPUT
448
A[19:16]/BA0/BA1
Output
CTRL
447
A20
Output
OUTPUT
446
A[22:20]/NWE/NWR0
Output
CTRL
445
A21
Output
OUTPUT
444
A22
Output
OUTPUT
443
442
INPUT
PC7/A23
I/O
441
CTRL
440
INPUT
439
PC8/A24
I/O
OUTPUT
438
CTRL
437
INPUT
436
PC9/A25/CFRNW
I/O
435
OUTPUT
CTRL
434
NCS0/BFCS
Output
OUTPUT
433
NCS[1:0]/NOE/NRD/NUB/
NWR1/NBS1/BFCS/SDCS
Output
CTRL
432
NCS1/SDCS
Output
OUTPUT
431
NCS2
Output
OUTPUT
430
NCS[2:3]/NBS3
Output
CTRL
429
NCS3
Output
OUTPUT
428
NOE/NRD
Output
OUTPUT
NWE/NWR0
Output
427
INPUT
426
OUTPUT
425
INPUT
NUB/NWR1/NBS1
Output
424
68
OUTPUT
OUTPUT
423
NBS3
Output
OUTPUT
422
SDCKE
Output
OUTPUT
421
SDCKE/RAS/CAS/WE/SDA10
Output
CTRL
420
RAS
Output
OUTPUT
419
CAS
Output
OUTPUT
418
WE
Output
OUTPUT
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table 12-3.
Bit
Number
JTAG Boundary Scan Register (Continued)
Pin Name
Pin Type
D0
I/O
417
INPUT
416
415
OUTPUT
D[3:0]
I/O
D1
I/O
414
OUTPUT
412
INPUT
D2
I/O
411
OUTPUT
410
INPUT
D3
I/O
409
OUTPUT
408
INPUT
D4
I/O
407
OUTPUT
D[7:4]
I/O
D5
I/O
405
OUTPUT
403
INPUT
D6
I/O
402
OUTPUT
401
INPUT
D7
I/O
400
OUTPUT
399
INPUT
D8
I/O
398
OUTPUT
D[11:8]
I/O
D9
I/O
396
OUTPUT
394
INPUT
D10
I/O
393
OUTPUT
392
INPUT
D11
I/O
391
OUTPUT
390
INPUT
D12
I/O
389
OUTPUT
D[15:12]
I/O
D13
I/O
387
CTRL
INPUT
386
OUTPUT
385
INPUT
D14
384
CTRL
INPUT
395
388
CTRL
INPUT
404
397
CTRL
INPUT
413
406
Associated BSR
Cells
I/O
OUTPUT
69
1768I–ATARM–09-Jul-09
Table 12-3.
Bit
Number
JTAG Boundary Scan Register (Continued)
Pin Name
Pin Type
D15
I/O
383
INPUT
382
OUTPUT
381
INPUT
380
PC16/D16
I/O
OUTPUT
379
CTRL
378
INPUT
377
PC17D17
I/O
OUTPUT
376
CTRL
375
INPUT
374
PC18/D18
I/O
OUTPUT
373
CTRL
372
INPUT
371
PC19/D19
I/O
OUTPUT
370
CTRL
369
INPUT
368
PC20/D20
I/O
OUTPUT
367
CTRL
366
INPUT
365
PC21/D21
I/O
OUTPUT
364
CTRL
363
INPUT
362
PC22/D22
I/O
OUTPUT
361
CTRL
360
INPUT
359
PC23/D23
I/O
OUTPUT
358
CTRL
357
INPUT
356
PC24/D24
I/O
OUTPUT
355
CTRL
354
INPUT
353
PC25/D25
I/O
OUTPUT
352
CTRL
351
INPUT
350
349
70
Associated BSR
Cells
PC26/D26
I/O
OUTPUT
CTRL
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table 12-3.
Bit
Number
JTAG Boundary Scan Register (Continued)
Pin Name
Pin Type
348
347
Associated BSR
Cells
INPUT
PC27/D27
I/O
OUTPUT
346
CTRL
345
INPUT
344
PC28/D28
I/O
OUTPUT
343
CTRL
342
INPUT
341
PC29/D29
I/O
OUTPUT
340
CTRL
339
INPUT
338
PC30/D30
I/O
OUTPUT
337
CTRL
336
INPUT
335
PC31/D31
I/O
OUTPUT
334
CTRL
333
INPUT
332
PC10/NCS4/CFCS
I/O
OUTPUT
331
CTRL
330
INPUT
329
PC11/NCS5/CFCE1
I/O
OUTPUT
328
CTRL
327
INPUT
326
PC12/NCS6/CFCE2
I/O
OUTPUT
325
CTRL
324
INPUT
323
PC13/NCS7
I/O
OUTPUT
322
CTRL
321
INPUT
320
PC14
I/O
OUTPUT
319
CTRL
318
INPUT
317
316
PC15
I/O
OUTPUT
CTRL
71
1768I–ATARM–09-Jul-09
Table 12-3.
Bit
Number
JTAG Boundary Scan Register (Continued)
Pin Name
Pin Type
315
314
INPUT
PC0/BCFK
I/O
OUTPUT
313
CTRL
312
INPUT
311
PC1/BFRDY/SMOE
I/O
OUTPUT
310
CTRL
309
INPUT
308
PC2/BFAVD
I/O
OUTPUT
307
CTRL
306
INPUT
305
PC3/BFBAA/SMWE
I/O
OUTPUT
304
CTRL
303
INPUT
302
PC4/BFOE
I/O
OUTPUT
301
CTRL
300
INPUT
299
PC5/BFWE
I/O
OUTPUT
298
CTRL
297
INPUT
296
PC6/NWAIT
I/O
OUTPUT
295
CTRL
294
INPUT
293
PA0/MISO/PCK3
I/O
OUTPUT
292
CTRL
291
INPUT
290
PA1/MOSI/PCK0
I/O
OUTPUT
289
CTRL
288
INPUT
287
PA2/SPCK/IRQ4
I/O
OUTPUT
286
CTRL
285
INPUT
284
283
72
Associated BSR
Cells
PA3/NPCS0/IRQ5
I/O
OUTPUT
CTRL
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table 12-3.
Bit
Number
JTAG Boundary Scan Register (Continued)
Pin Name
Pin Type
282
281
Associated BSR
Cells
INPUT
PA4/NPCS1/PCK1
I/O
OUTPUT
280
CTRL
279
INPUT
278
PA5/NPCS2/TXD3
I/O
OUTPUT
277
CTRL
276
INPUT
275
PD0/ETX0
I/O
OUTPUT
274
CTRL
273
INPUT
272
PD1/ETX1
I/O
OUTPUT
271
CTRL
270
INPUT
269
PD2/ETX2
I/O
OUTPUT
268
CTRL
267
INPUT
266
PD3/ETX3
I/O
OUTPUT
265
CTRL
264
INPUT
263
PD4/ETXEN
I/O
OUTPUT
262
CTRL
261
INPUT
260
PD5/ETXER
I/O
OUTPUT
259
CTRL
258
INPUT
257
PD6/DTXD
I/O
OUTPUT
256
CTRL
255
INPUT
254
PA6/NPCS3/RXD3
I/O
OUTPUT
253
CTRL
252
INPUT
251
250
PA7/ETXCK/EREFCK/PCK2
I/O
OUTPUT
CTRL
73
1768I–ATARM–09-Jul-09
Table 12-3.
Bit
Number
JTAG Boundary Scan Register (Continued)
Pin Name
Pin Type
249
248
INPUT
PA8/ETXEN/MCCDB
I/O
OUTPUT
247
CTRL
246
INPUT
245
PA9/ETX0/MCDB0
I/O
OUTPUT
244
CTRL
243
INPUT
242
PA10/ETX1/MCDB1
I/O
OUTPUT
241
CTRL
240
INPUT
239
PA11/ECRS/ECRSDV/MCDB2
I/O
OUTPUT
238
CTRL
237
INPUT
236
PA12/ERX0/MCDB3
I/O
OUTPUT
235
CTRL
234
INPUT
233
PA13/ERX1/TCLK0
I/O
OUTPUT
232
CTRL
231
INPUT
230
PA14/ERXER/TCLK1
I/O
OUTPUT
229
CTRL
228
INPUT
227
PA15/EMDC/TCLK2
I/O
OUTPUT
226
CTRL
225
INPUT
224
PA16/EMDIO/IRQ6
I/O
OUTPUT
223
CTRL
222
INPUT
221
PA17/TXD0/TIOA0
I/O
OUTPUT
220
CTRL
219
INPUT
218
217
74
Associated BSR
Cells
PA18/RXD0/TIOB0
I/O
OUTPUT
CTRL
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table 12-3.
Bit
Number
JTAG Boundary Scan Register (Continued)
Pin Name
Pin Type
216
215
Associated BSR
Cells
INPUT
PA19/SCK0/TIOA1
I/O
OUTPUT
214
CTRL
213
INPUT
212
PA20/CTS0/TIOB1
I/O
OUTPUT
211
CTRL
210
INPUT
209
PA21/RTS0/TIOA2
I/O
OUTPUT
208
CTRL
207
INPUT
206
PA22/RXD2/TIOB2
I/O
OUTPUT
205
CTRL
204
INPUT
203
PA23/TXD2/IRQ3
I/O
OUTPUT
202
CTRL
201
INPUT
200
PA24/SCK2/PCK1
I/O
OUTPUT
199
CTRL
198
INPUT
197
PA25/TWD/IRQ2
I/O
OUTPUT
196
CTRL
195
INPUT
194
PA26/TWCK/IRQ1
I/O
OUTPUT
193
CTRL
192
INPUT
191
PA27/MCCK/TCLK3
I/O
OUTPUT
190
CTRL
189
INPUT
188
PA28/MCCDA/TCLK4
I/O
OUTPUT
187
CTRL
186
INPUT
185
184
PA29/MCDA0/TCLK5
I/O
OUTPUT
CTRL
75
1768I–ATARM–09-Jul-09
Table 12-3.
Bit
Number
JTAG Boundary Scan Register (Continued)
Pin Name
Pin Type
183
182
INPUT
PA30/DRXD/CTS2
I/O
OUTPUT
181
CTRL
180
INPUT
179
PA31/DTXD/RTS2
I/O
OUTPUT
178
CTRL
177
INPUT
176
PB0/TF0/RTS3
I/O
OUTPUT
175
CTRL
174
INPUT
173
PB1/TK0/CTS3
I/O
OUTPUT
172
CTRL
171
INPUT
170
PB2/TD0/SCK3
I/O
OUTPUT
169
CTRL
168
INPUT
167
PB3/RD0/MCDA1
I/O
OUTPUT
166
CTRL
165
INPUT
164
PB4/RK0/MCDA2
I/O
OUTPUT
163
CTRL
162
INPUT
161
PB5/RF0/MCDA3
I/O
OUTPUT
160
CTRL
159
INPUT
158
PB6/TF1/TIOA3
I/O
OUTPUT
157
CTRL
156
INPUT
155
PB7/TK1/TIOB3
I/O
OUTPUT
154
CTRL
153
INPUT
152
151
76
Associated BSR
Cells
PB8/TD1/TIOA4
I/O
OUTPUT
CTRL
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table 12-3.
Bit
Number
JTAG Boundary Scan Register (Continued)
Pin Name
Pin Type
150
149
Associated BSR
Cells
INPUT
PB9/RD1/TIOB4
I/O
OUTPUT
148
CTRL
147
INPUT
146
PB10/RK1/TIOA5
I/O
OUTPUT
145
CTRL
144
INPUT
143
PB11/RF1/TIOB5
I/O
OUTPUT
142
CTRL
141
INPUT
140
PB12/TF2/ETX2
I/O
OUTPUT
139
CTRL
138
INPUT
137
PB13/TK2/ETX3
I/O
OUTPUT
136
CTRL
135
INPUT
134
PB14/TD2/ETXER
I/O
OUTPUT
133
CTRL
132
INPUT
131
PB15/RD2/ERX2
I/O
OUTPUT
130
CTRL
129
INPUT
128
PB16/RK2/ERX3
I/O
OUTPUT
127
CTRL
126
INPUT
125
PD7/PCK0/TSYNC
I/O
OUTPUT
124
CTRL
123
INPUT
122
PD8/PCK1/TCLK
I/O
OUTPUT
121
CTRL
120
INPUT
119
118
PD9/PCK2/TPS0
I/O
OUTPUT
CTRL
77
1768I–ATARM–09-Jul-09
Table 12-3.
Bit
Number
JTAG Boundary Scan Register (Continued)
Pin Name
Pin Type
117
116
INPUT
PD10/PCK3/TPS1
I/O
OUTPUT
115
CTRL
114
INPUT
113
PD11/TPS2
I/O
OUTPUT
112
CTRL
111
INPUT
110
PD12/TPK0
I/O
OUTPUT
109
CTRL
108
INPUT
107
PB17/RF2/ERXDV
I/O
OUTPUT
106
CTRL
105
INPUT
104
PB18/RI1/ECOL
I/O
OUTPUT
103
CTRL
102
INPUT
101
PB19/DTR1/ERXCK
I/O
OUTPUT
100
CTRL
99
INPUT
98
PB20/TXD1
I/O
OUTPUT
97
CTRL
96
INPUT
95
PB21/RXD1
I/O
OUTPUT
94
CTRL
93
INPUT
92
PB22/SCK1
I/O
OUTPUT
91
CTRL
90
INPUT
89
PD13/TPK1
I/O
OUTPUT
88
CTRL
87
INPUT
86
85
78
Associated BSR
Cells
PD14/TPK2
I/O
OUTPUT
CTRL
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table 12-3.
Bit
Number
JTAG Boundary Scan Register (Continued)
Pin Name
Pin Type
84
83
Associated BSR
Cells
INPUT
PD15/TD0/TPK3
I/O
OUTPUT
82
CTRL
81
INPUT
80
PB23/DCD1
I/O
OUTPUT
79
CTRL
78
INPUT
77
PB24/CTS1
I/O
OUTPUT
76
CTRL
75
INPUT
74
PB25/DSR1/EF100
I/O
OUTPUT
73
CTRL
72
INPUT
71
PB26/RTS1
I/O
OUTPUT
70
CTRL
69
INPUT
68
PB27/PCK0
I/O
OUTPUT
67
CTRL
66
INPUT
65
PD16/TD1/TPK4
I/O
OUTPUT
64
CTRL
63
INPUT
62
PD17/TD2/TPK5
I/O
OUTPUT
61
CTRL
60
INPUT
59
PD18/NPCS1/TPK6
I/O
OUTPUT
58
CTRL
57
INPUT
56
PD19/NPCS2/TPK7
I/O
OUTPUT
55
CTRL
54
INPUT
53
52
PD20/NPCS3/TPK8
I/O
OUTPUT
CTRL
79
1768I–ATARM–09-Jul-09
Table 12-3.
Bit
Number
JTAG Boundary Scan Register (Continued)
Pin Name
Pin Type
51
50
INPUT
PD21/RTS0/TPK9
I/O
OUTPUT
49
CTRL
48
INPUT
47
PD22/RTS1/TPK10
I/O
OUTPUT
46
CTRL
45
INPUT
44
PD23/RTS2/TPK11
I/O
OUTPUT
43
CTRL
42
INPUT
41
PD24/RTS3/TPK12
I/O
OUTPUT
40
CTRL
39
INPUT
38
PD25/DTR1/TPK13
I/O
OUTPUT
37
CTRL
36
INPUT
35
PD26/TPK14
I/O
OUTPUT
34
CTRL
33
INPUT
32
PD27/TPK15
I/O
OUTPUT
31
CTRL
30
INPUT
29
PB28/FIQ
I/O
OUTPUT
28
CTRL
27
INPUT
26
PB29/IRQ0
I/O
25
80
Associated BSR
Cells
OUTPUT
CTRL
24
A0/NLB/NBS0
Output
OUPUT
23
A[3:0]/NLB/NWR2/NBS0
/NBS2
Output
CTRL
22
A1/NWR2/NBS2
Output
OUTPUT
21
A2
Output
OUTPUT
20
A3
Output
OUTPUT
19
A4
Output
OUTPUT
18
A[7:4]
Output
CTRL
17
A5
Output
OUTPUT
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table 12-3.
JTAG Boundary Scan Register (Continued)
Bit
Number
Pin Name
Pin Type
Associated BSR
Cells
16
A6
Output
OUTPUT
15
A7
Output
OUTPUT
14
A8
Output
OUTPUT
13
A[11:8]
Output
CTRL
12
A9
Output
OUTPUT
11
A10
Output
OUTPUT
10
SDA10
Output
OUTPUT
9
A11
Output
OUTPUT
8
A12
Output
OUTPUT
7
A[15:12]
Output
CTRL
6
A13
Output
OUTPUT
5
A14
Output
OUTPUT
4
A15
Output
OUTPUT
3
A16/BA0
Output
OUTPUT
2
A17/BA1
Output
OUTPUT
1
A18
Output
OUTPUT
81
1768I–ATARM–09-Jul-09
12.6.6
AT91RM9200 ID Code Register
Access: Read-only
31
30
29
28
27
VERSION
23
22
26
25
24
PART NUMBER
21
20
19
18
17
16
10
9
8
PART NUMBER
15
14
13
12
11
PART NUMBER
7
6
MANUFACTURER IDENTITY
5
4
3
MANUFACTURER IDENTITY
2
1
0
1
• VERSION[31:28]: Product Version Number
Set to 0x0 = JTAGSEL is low.
Set to 0x1 = JTAGSEL is high.
• PART NUMBER[27:14]: Product Part Number
Set to 0x5b02.
• MANUFACTURER IDENTITY[11:1]
Set to 0x01f.
• Bit [0]: Required by IEEE Std. 1149.1
Set to 1.
The AT91RM9200 ID Code value is 0x15b0203f (JTAGSEL is High).
The AT91RM9200 ID Code value is 0x05b0203f (JTAGSEL is Low).
82
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1768I–ATARM–09-Jul-09
AT91RM9200
13. Boot Program
13.1
Overview
The Boot Program is capable of downloading an application in an AT91RM9200-based system.
It integrates a Bootloader and a boot Uploader to assure correct information download.
The Bootloader is activated first. It looks for a sequence of eight valid ARM exception vectors in
a DataFlash connected to the SPI, an EEPROM connected to the Two-wire Interface (TWI) or
an 8-bit memory device connected to the external bus interface (EBI). All these vectors must be
Bbranch or LDR load register instructions except for the sixth instruction. This vector is used to
store information, such as the size of the image to download and the type of DataFlash device.
If a valid sequence is found, code is downloaded into the internal SRAM. This is followed by a
remap and a jump to the first address of the SRAM.
If no valid ARM vector sequence is found, the boot Uploader is started. It initializes the Debug
Unit serial port (DBGU) and the USB Device Port. It then waits for any transaction and downloads a piece of code into the internal SRAM via a Device Firmware Upgrade (DFU) protocol for
USB and XMODEM protocol for the DBGU. After the end of the download, it branches to the
application entry point at the first address of the SRAM.
The main features of the Boot Program are:
• Default Boot Program stored in ROM-based products
• Downloads and runs an application from external storage media into internal SRAM
• Downloaded code size depends on embedded SRAM size
• Automatic detection of valid application
• Bootloader supporting a wide range of non-volatile memories
– SPI DataFlash connected on SPI NPCS0
– Two-wire EEPROM
– 8-bit parallel memories on NCS0
• Boot Uploader in case no valid program is detected in external NVM and supporting several
communication media
• Serial communication on a DBGU (XModem protocol)
• USB Device Port (DFU Protocol)
83
1768I–ATARM–09-Jul-09
13.2
Flow Diagram
The Boot Program implements the algorithm presented in Figure 13-1.
Figure 13-1. Boot Program Algorithm Flow Diagram
Device
Setup
SPI DataFlash
Boot
Yes
Download from
DataFlash
Run
Timeout 10 ms
TWI
EEPROM Boot
Yes
Bootloader
Download from
EEPROM
Run
Download from
8-bit Device
Run
DBGU Serial
Download
Run
Timeout 40 ms
Yes
Parallel
Boot
Boot Uploader
OR
USB Download
DFU* protocol
Run
*DFU = Device Firmware Upgrade
84
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
13.3
Bootloader
The Boot Program is started from address 0x0000_0000 (ARM reset vector) when the on-chip
boot mode is selected (BMS high during the reset, only on devices with EBI integrated). The first
operation is the search for a valid program in the off-chip non-volatile memories. If a valid application is found, this application is loaded into internal SRAM and executed by branching at
address 0x0000_0000 after remap. This application may be the application code or a secondlevel Bootloader.
To optimize the downloaded application code size, the Boot Program embeds several functions
that can be reused by the application. The Boot Program is linked at address 0x0010_0000 but
the internal ROM is mapped at both 0x0000_0000 and 0x0010_0000 after reset. All the call to
functions is PC relative and does not use absolute addresses. The ARM vectors are present at
both addresses, 0x0000_0000 and 0x0010_0000.
To access the functions in ROM, a structure containing chip descriptor and function entry points
is defined at a fixed address in ROM.
If no valid application is detected, the debug serial port or the USB device port must be connected to allow the upload. A specific application provided by Atmel (DFU uploader) loads the
application into internal SRAM through the USB. To load the application through the debug
serial port, a terminal application (HyperTerminal) running the Xmodem protocol is required.
Figure 13-2. Remap Action after Download Completion
Internal
SRAM
Internal
ROM
REMAP
0x0020_0000
Internal
ROM
0x0000_0000
0x0010_0000
Internal
SRAM
0x0000_0000
After reset, the code in internal ROM is mapped at both addresses 0x0000_0000 and
0x0010_0000:
100000
ea00000b
B
0x2c00ea00000bB0x2c
100004
e59ff014
LDR
PC,[PC,20]04e59ff014LDRPC,[PC,20]
100008
e59ff014
LDR
PC,[PC,20]08e59ff014LDRPC,[PC,20]
10000c
e59ff014
LDR
PC,[PC,20]0ce59ff014LDRPC,[PC,20]
100010
e59ff014
LDR
PC,[PC,20]10e59ff014LDRPC,[PC,20]
100014
00001234
LDR
PC,[PC,20]1400001234LDRPC,[PC,20]
100018
e51fff20
LDR
PC,[PC,-0xf20]18e51fff20LDRPC,[PC,-0xf20]
10001c
e51fff20
LDR
PC,[PC,-0xf20]1ce51fff20LDRPC,[PC,-0xf20]
85
1768I–ATARM–09-Jul-09
13.3.1
Valid Image Detection
The Bootloader software looks for a valid application by analyzing the first 32 bytes corresponding to the ARM exception vectors. These bytes must implement ARM instructions for either
branch or load PC with PC relative addressing. The sixth vector, at offset 0x14, contains the size
of the image to download and the DataFlash parameters.
The user must replace this vector with his own vector.
Figure 13-3. LDR Opcode
31
1
28 27
1
1
0
0
24 23
1
I
P
U
20 19
0
W
1
16 15
Rn
12 11
0
Rd
Figure 13-4. B Opcode
31
1
28 27
1
1
0
1
24 23
0
1
0
0
Offset (24 bits)
Unconditional instruction: 0xE for bits 31 to 28
Load PC with PC relative addressing instruction:
– Rn = Rd = PC = 0xF
– I==1
– P==1
– U offset added (U==1) or subtracted (U==0)
– W==1
13.3.1.1
Example
An example of valid vectors:
00
ea00000b
B
0x2c
004
e59ff014
LDR
PC, [PC,20]
08
e59ff014
LDR
PC, [PC,20]
0c
e59ff014
LDR
PC, [PC,20]
10
e59ff014
LDR
PC, [PC,20]
14
00001234
18
e51fff20
LDR
PC, [PC,-0xf20]
1c
e51fff20
LDR
PC, [PC,-0xf20]
<- Code size = 4660 bytes
In download mode (DataFlash, EEPROM or 8-bit memory in device with EBI integrated), the
size of the image to load into SRAM is contained in the location of the sixth ARM vector. Thus
the user must replace this vector by the correct vector for his application.
86
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
13.3.2
Structure of ARM Vector 6
The ARM exception vector 6 is used to store information needed by the Boot ROM downloader.
This information is described below.
Figure 13-5. Structure of the ARM vector 6
31
17 16
DataFlash page size
13 12
Number of
pages
8
7
0
Nb of 512 bytes blocks to
download
Reserved
The first eight bits contain the number of blocks to download. The size of a block is 512 bytes,
allowing download of up to 128K bytes.
The bits 13 to 16 determine the DataFlash page number.
– DataFlash page number = 2(Nb of pages)
The last 15 bits contain the DataFlash page size.
Table 13-1.
Device
13.3.2.1
DataFlash Device
Density
Page Size (bytes)
Number of pages
AT45DB011B
1 Mbit
264
512
AT45DB021B
2 Mbits
264
1024
AT45DB041B
4 Mbits
264
2048
AT45DB081B
8 Mbits
264
4096
AT45DB161B
16 Mbits
528
4096
AT45DB321B
32 Mbits
528
8192
AT45DB642
64 Mbits
1056
8192
AT45DB1282
128 Mbits
1056
16384
Example
The following vector contains the information to describe a AT45DB642 DataFlash which contains 11776 bytes to download.
Vector 6 is 0x0841A017 (00001000010000011010000000010111b):
Size to download: 0x17 * 512 bytes = 11776 bytes
Number pages (1101b): 13 ==> Number of DataFlash pages = 213 = 8192
DataFlash page size(000010000100000b) = 1056
For download in the EEPROM or 8-bit external memory, only the size to be downloaded is
decoded.
87
1768I–ATARM–09-Jul-09
13.3.3
13.3.3.1
Bootloader Sequence
The Boot Program performs device initialization followed by the download procedure. If unsuccessful, the upload is done via the USB or debug serial port.
Device Initialization
Initialization follows the steps described below:
1. PLL setup
– PLLB is initialized to generate a 48 MHz clock necessary to use the USB Device. A
register located in the Power Management Controller (PMC) determines the
frequency of the main oscillator and thus the correct factor for the PLLB.
Table 13-2 defines the crystals supported by the Boot Program.
Table 13-2.
Crystals Supported by Software Auto-detection (MHz)
3.0
3.2768
3.6864
3.84
4.0
4.433619
4.9152
5.0
5.24288
6.0
6.144
6.4
6.5536
7.159090
7.3728
7.864320
8.0
9.8304
10.0
11.05920
12.0
12.288
13.56
14.31818
14.7456
16.0
17.734470
18.432
20.0
2. Stacks setup for each ARM mode
3. Main oscillator frequency detection
4. Interrupt controller setup
5. C variables initialization
6. Branch main function
13.3.3.2
88
Download Procedure
The download procedure checks for a valid boot on several devices. The first device checked is
a serial DataFlash connected to the NPCS0 of the SPI, followed by the serial EEPROM connected to the TWI and by an 8-bit parallel memory connected on NCS0 of the External Bus
Interface.
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
13.3.3.3
Serial DataFlash Download
The Boot Program supports all Atmel DataFlash devices. Table 13-1 summarizes the parameters to include in the ARM vector 6 for all devices.
The DataFlash has a Status Register that determines all the parameters required to access the
device.
Thus, to be compatible with the future design of the DataFlash, parameters are coded in the
ARM vector 6.
Figure 13-6. Serial DataFlash Download
Start
Send status command
Is status ok ?
No
Serial DataFlash
Download
Read the first 8 instructions (32 bytes).
Decode the sixth ARM vector
Yes
8 vectors
(except vector 6) are LDR
or Branch instruction ?
No
Yes
Read the DataFlash into the internal SRAM.
(code size to read in vector 6)
Restore the reset value for the peripherals.
Set the PC to 0 and perform the REMAP
to jump to the downloaded application
End
89
1768I–ATARM–09-Jul-09
13.3.3.4
Serial Two-wire EEPROM Download
Generally, serial EEPROMs have no identification code. The bootloader checks for an acknowledgment on the first read. The device address on the two-wire bus must be 0x0. The bootloader
supports the devices listed in Table 13-3.
Table 13-3.
Supported EEPROM Devices
Device
Size
Organization
AT24C16A
16 Kbits
16 bytes page write
AT24C164
16 Kbits
16 bytes page write
AT24C32
32 Kbits
32 bytes page write
AT24C64
64 Kbits
32 bytes page write
AT24C128
128 Kbits
64 bytes page write
AT24C256
256 Kbits
64 bytes page write
AT24C512
528 Kbits
128 bytes page write
Figure 13-7. Serial Two-Wire EEPROM Download
Start
Send Read command
8-bits parallel memory
Download
Device ACK ?
No
Only for Device with EBI integrated
Memory Uploader
Only for Device without
EBI integrated
Read the first 8 instructions (32 bytes).
Decode the sixth ARM vector
Yes
8 vectors
(except vector 6) are LDR
or Branch instruction ?
No
Yes
Read the Two-Wire EEPROM into the
internal SRAM
(code size to read in vector 6)
Restore the reset value for the peripherals.
Set the PC to 0 and perform the REMAP
to jump to the downloaded application
End
90
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
13.3.3.5
8-bit Parallel Flash Download (Applicable to Devices with EBI)
Eight-bit parallel Flash download is supported if the product integrates an External Bus Interface
(EBI).
All 8-bit memory devices supported by the EBI when NCS0 is configured in 8-bit data bus width
are supported by the bootloader.
Figure 13-8. 8-bit Parallel Flash Download
Start
Setup memory controller
Read the first 8 instructions (32 bytes).
Read the size in sixth ARM vector
8 vectors
(except vector 6) are LDR
or Branch instruction ?
No
Memory uploader
Yes
Read the external memory into the
internal SRAM
(code size to read in vector 6)
Restore the reset value for the peripherals.
Set the PC to 0 and perform the REMAP
to jump to the downloaded application
End
91
1768I–ATARM–09-Jul-09
13.4
Boot Uploader
If no valid boot device has been found during the Bootloader sequence, initialization of serial
communication devices (DBGU and USB device ports) is performed.
– Initialization of the DBGU serial port (115200 bauds, 8, N, 1) and Xmodem protocol
start
– Initialization of the USB Device Port and DFU protocol start
– Download of the application
The boot Uploader performs the DFU and Xmodem protocols to upload the application into internal SRAM at address 0x0020_0000.
The Boot Program uses a piece of internal SRAM for variables and stacks. To prevent any
upload error, the size of the application to upload must be less than the SRAM size minus 3K
bytes.
After the download, the peripheral registers are reset, the interrupts are disabled and the remap
is performed. After the remap, the internal SRAM is at address 0x0000_0000 and the internal
ROM at address 0x0010_0000. The instruction setting the PC to 0 is the one just after the remap
command. This instruction is fetched in the pipe before doing the remap and executed just after.
This fetch cycle executes the downloaded image.
13.4.1
13.4.1.1
External Communication Channels
DBGU Serial Port
The upload is performed through the DBGU serial port initialized to 115200 Baud, 8, n, 1.
The DBGU sends the character ‘C’ (0x43) to start an Xmodem protocol. Any terminal performing
this protocol can be used to send the application file to the target. The size of the binary file to
send depends on the SRAM size embedded in the product (Refer to the microcontroller
datasheet to determine SRAM size embedded in the microcontroller). In all cases, the size of the
binary file must be lower than SRAM size because the Xmodem protocol requires some SRAM
memory to work.
13.4.1.2
Xmodem Protocol
The Xmodem protocol supported is the 128-byte length block. This protocol uses a two character CRC-16 to guarantee detection of a maximum bit error.
Xmodem protocol with CRC is accurate provided both sender and receiver report successful
transmission. Each block of the transfer looks like:
<SOH><blk #><255-blk #><--128 data bytes--><checksum> in which:
– <SOH> = 01 hex
– <blk #> = binary number, starts at 01, increments by 1, and wraps 0FFH to 00H (not
to 01)
– <255-blk #> = 1’s complement of the blk#.
– <checksum> = 2 bytes CRC16
Figure 13-9 shows a transmission using this protocol.
92
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Figure 13-9. Xmodem Transfer Example
Host
Device
C
SOH 01 FE Data[128] CRC CRC
ACK
SOH 02 FD Data[128] CRC CRC
ACK
SOH 03 FC Data[100] CRC CRC
ACK
EOT
ACK
13.4.1.3
USB Device Port
A 48 MHz USB clock is necessary to use USB Device port. It has been programmed earlier in
the device initialization with PLLB configuration.
13.4.1.4
DFU Protocol
The DFU allows upgrade of the firmware of USB devices. The DFU algorithm is a part of the
USB specification. For more details, refer to “USB Device Firmware Upgrade Specification, Rev.
1.0”.
There are four distinct steps when carrying out a firmware upgrade:
1. Enumeration: The device informs the host of its capabilities.
2. Reconfiguration: The host and the device agree to initiate a firmware upgrade.
3. Transfer: The host transfers the firmware image to the device. Status requests are
employed to maintain synchronization between the host and the device.
4. Manifestation: Once the device reports to the host that it has completed the reprogramming operations, the host issues a reset and the device executes the upgraded
firmware.
Figure 13-10. DFU Protocol
Host
Device
Prepare for an upgrade
USB reset
DFU mode activated
Download this firmware
Prepare to exit DFU mode
USB reset
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13.5
Hardware and Software Constraints
The software limitations of the Boot Program are:
• The downloaded code size is less than the SRAM size -4K embedded in the product.
• The device address of the EEPROM must be 0 on the TWI bus.
• The code is always downloaded from the device address 0x0000_0000 (DataFlash,
EEPROM) to the address 0x0000_0000 of the internal SRAM (after remap).
• The downloaded code must be position-independent or linked at address 0x0000_0000.
The hardware limitations of the Boot Program are:
• The DataFlash must be connected to NPCS0 of the SPI.
• The 8-bit parallel Flash must be connected to NCS0 of the EBI.
• The Boot Program initializes the DBGU pins multiplexed on the PIO common to both the 208lead PQFP and 256-ball BGA packages, in this case meaning PIOA.
• Using an external clock source on the XIN pin is not possible as the main oscillator is enabled
by the Boot ROM.
The SPI and TWI drivers use several PIOs in alternate functions to communicate with devices.
Care must be taken when these PIOs are used by the application. The devices connected could
be unintentionally driven at boot time, and electrical conflicts between SPI or TWI output pins
and the connected devices may appear.
To assure correct functionality, it is recommended to plug in critical devices to other pins or to
boot on an external 16-bit parallel memory by setting bit BMS.
Table 13-4 contains a list of pins that are driven during the Boot Program execution. These pins
are driven during the boot sequence for a period of about 6 ms if no correct boot program is
found. The download through the TWI takes about 5 sec for 64K bytes due to the TWI bit rate
(100 Kbits/s).
For the DataFlash driven by SPCK signal at 12 MHz, the time to download 64K bytes is reduced
to 66 ms.
Before performing the jump to the application in internal SRAM, all the PIOs and peripherals
used in the Boot Program are set to their reset state.
Table 13-4.
Pin Used
SPI (DataFlash)
TWI (EEPROM)
(1)
O
X
(1)
O
X
NPCS0
O
X
TWD(1)
X
I/O
X
O
MOSI
SPCK
(1)
(1)
TWCK
Note:
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Pins Driven during Boot Program Execution
1. See Section 10.3 “Peripheral Multiplexing on PIO Lines” on page 22.
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14. Embedded Software Services
14.1
Overview
An embedded software service is an independent software object that drives device resources
for frequently implemented tasks. The object-oriented approach of the software provides an
easy way to access services to build applications.
An AT91 service has several purposes:
• It gives software examples dedicated to the AT91 devices.
• It can be used on several AT91 device families.
• It offers an interface to the software stored in the ROM.
The main features of the software services are:
• Compliant with ATPCS
• Compliant with ANSI/ISO Standard C
• Compiled in ARM/Thumb Interworking
• ROM Entry Service
• Tempo, Xmodem and DataFlash services
• CRC and Sine tables
14.2
Service Definition
14.2.1
Service Structure
14.2.1.1
Structure Definition
A service structure is defined in C header files.
This structure is composed of data members and pointers to functions (methods) and is similar
to a class definition. There is no protection of data access or methods access. However, some
functions can be used by the customer application or other services and so be considered as
public methods. Similarly, other functions are not invoked by them. They can be considered as
private methods. This is also valid for data.
14.2.1.2
Methods
In the service structure, pointers to functions are supposed to be initialized by default to the standard functions. Only the default standard functions reside in ROM. Default methods can be
overloaded by custom application methods.
Methods do not declare any static variables nor invoke global variables. All methods are invoked
with a pointer to the service structure. A method can access and update service data without
restrictions.
Similarly, there is no polling in the methods. In fact, there is a method to start the functionality (a
read to give an example), a method to get the status (is the read achieved?), and a callback, initialized by the start method. Thus, using service, the client application carries out a synchronous
read by starting the read and polling the status, or an asynchronous read specifying a callback
when starting the read operation.
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14.2.1.3
Service Entry Point
Each AT91 service, except for the ROM Entry Service (see 14.3.2 “ROM Entry Service” on
page 99), defines a function named AT91F_Open_<Service>. It is the only entry point defined
for a service. Even if the functions AT91F_Open_<Service> may be compared with object
constructors, they do not act as constructors in that they initiate the service structure but they do
not allocate it. Thus the customer application must allocate it.
Example
// Allocation of the service structure
AT91S_Pipe pipe;
// Opening of the service
AT91PS_Pipe pPipe = AT91F_OpenPipe(&pipe, …);
Method pointers in the service structure are initialized to the default methods defined in the
AT91 service. Other fields in the service structure are initialized to default values or with the
arguments of the function AT91F_Open_<Service>.
In summary, an application must know what the service structure is and where the function
AT91F_Open_<Service> is.
The default function AT91F_Open_<Service> may be redefined by the application or comprised in an application-defined function.
14.2.2
14.2.2.1
Using a Service
Opening a Service
The entry point to a service is established by initializing the service structure. An open function is
associated with each service structure, except for the ROM Entry Service (see 14.3.2 “ROM
Entry Service” on page 99). Thus, only the functions AT91F_Open_<service> are visible from
the user side. Access to the service methods is made via function pointers in the service
structure.
The function AT91F_Open_<service> has at least one argument: a pointer to the service
structure that must be allocated elsewhere. It returns a pointer to the base service structure or a
pointer to this service structure.
The function AT91F_Open_<service> initializes all data members and method pointers. All
function pointers in the service structure are set to the service’s functions.
The advantage of this method is to offer a single entry point for a service. The methods of a service are initialized by the open function and each member can be overloaded.
14.2.2.2
Overloading a Method
Default methods are defined for all services provided in ROM. These methods may not be
adapted to a project requirement. It is possible to overload default methods by methods defined
in the project.
A method is a pointer to a function. This pointer is initialized by the function
AT91F_Open_<Service>. To overload one or several methods in a service, the function
pointer must be updated to the new method.
It is possible to overload just one method of a service or all the methods of a service. In this latter
case, the functionality of the service is user-defined, but still works on the same data structure.
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Note:
Calling the default function AT91F_Open_<Service> ensures that all methods and data are
initialized.
This can be done by writing a new function My_OpenService(). This new Open function must
call the library-defined function AT91F_Open_<Service>, and then update one or several
function pointers:
Table 14-1.
Overloading a Method with the Overloading of the Open Service Function
Default service behavior in ROM
// Defined in embedded_services.h
typedef struct _AT91S_Service {
Overloading AT91F_ChildMethod by My_ChildMethod
// My_ChildMethod will replace
AT91F_ChildMethod
char data;
char My_ChildMethod ()
char (*MainMethod) ();
{
char (*ChildMethod) ();
}
} AT91S_Service, * AT91PS_Service;
// Overloading Open Service Method
// Defined in obj_service.c (in ROM)
AT91PS_Service My_OpenService(
char AT91F_MainMethod ()
AT91PS_Service pService)
{
{
AT91F_OpenService(pService);
}
char AT91F_ChildMethod ()
// Overloading ChildMethod default value
{
pService->ChildMethod= My_ChildMethod;
}
return pService;
}
// Init the service with default methods
AT91PS_Service AT91F_OpenService(
// Allocation of the service structure
AT91PS_Service pService)
AT91S_Service service;
{
pService->data = 0;
// Opening of the service
pService->MainMethod =AT91F_MainMethod;
AT91PS_Service pService =
My_OpenService(&service);
pService->ChildMethod=AT91F_ChildMethod;
return pService;
}
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This also can be done directly by overloading the method after the use of AT91F_Open_<Service> method:
Table 14-2.
Overloading a Method without the Overloading of the Open Service Function.
Default service behavior in ROM
// Defined in embedded_services.h
typedef struct _AT91S_Service {
Overloading AT91F_ChildMethod by My_ChildMethod
// My_ChildMethod will replace
AT91F_ChildMethod
char data;
char My_ChildMethod ()
char (*MainMethod) ();
{
char (*ChildMethod) ();
}
} AT91S_Service, * AT91PS_Service;
// Allocation of the service structure
// Defined in obj_service.c (in ROM)
AT91S_Service service;
char AT91F_MainMethod ()
{
// Opening of the service
}
AT91PS_Service pService =
AT91F_OpenService(&service);
char AT91F_ChildMethod ()
// Overloading ChildMethod default value
{
pService->ChildMethod= My_ChildMethod;
}
// Init the service with default methods
AT91PS_Service AT91F_OpenService(
AT91PS_Service pService)
{
pService->data = 0;
pService->MainMethod =AT91F_MainMethod;
pService->ChildMethod=AT91F_ChildMethod;
return pService;
}
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14.3
14.3.1
Embedded Software Services
Definition
Several AT91 products embed ROM. In most cases, the ROM integrates a bootloader and several services that may speed up the application and reduce the application code size.
When software is fixed in the ROM, the address of each object (function, constant, table, etc.)
must be related to a customer application. This is done by providing an address table to the
linker. For each version of ROM, a new address table must be provided and all client applications must be recompiled.
The Embedded Software Services offer another solution to access objects stored in ROM. For
each embedded service, the customer application requires only the address of the Service Entry
Point (see 14.2.1.3 “Service Entry Point” on page 96).
Even if these services have only one entry point (AT91F_Open_<Service> function), they must
be specified to the linker. The Embedded Software Services solve this problem by providing a
dedicated service: the ROM Entry Service.
The goal of this product-dedicated service is to provide just one address to access all ROM
functionalities.
14.3.2
ROM Entry Service
The ROM Entry Service of a product is a structure named AT91S_RomBoot. Some members of
this structure point to the open functions of all services stored in ROM (function
AT91F_Open_<Service>) but also the CRC and Sine Arrays. Thus, only the address of the
AT91S_RomBoot has to be published.
Table 14-3.
Initialization of the ROM Entry Service and Use with an Open Service Method
Application Memory Space
ROM Memory Space
// Init the ROM Entry Service
AT91S_RomBoot const *pAT91;
pAT91 = AT91C_ROM_BOOT_ADDRESS;
AT91S_TempoStatus AT91F_OpenCtlTempo(
AT91PS_CtlTempo pCtlTempo,
void const *pTempoTimer )
{
// Allocation of the service structure
AT91S_CtlTempo tempo;
...
}
// Call the Service Open method
pAT91->OpenCtlTempo(&tempo, ...);
AT91S_TempoStatus AT91F_CtlTempoCreate (
AT91PS_CtlTempo pCtrl,
AT91PS_SvcTempo pTempo)
{
...
// Use of tempo methods
tempo.CtlTempoCreate(&tempo, ...);
}
The application obtains the address of the ROM Entry Service and initializes an instance of the
AT91S_RomBoot structure. To obtain the Open Service Method of another service stored in
ROM, the application uses the appropriate member of the AT91S_RomBoot structure.
The address of the AT91S_RomBoot can be found at the beginning of the ROM, after the exception vectors.
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14.3.3
Tempo Service
14.3.3.1
Presentation
The Tempo Service allows a single hardware system timer to support several software timers
running concurrently. This works as an object notifier.
There are two objects defined to control the Tempo Service: AT91S_CtlTempo and
AT91S_SvcTempo.
The application declares one instance of AT91S_CtlTempo associated with the hardware system timer. Additionally, it controls a list of instances of AT91S_SvcTempo.
Each time the application requires another timer, it asks the AT91S_CtlTempo to create a new
instance of AT91S_SvcTempo, then the application initializes all the settings of
AT91S_SvcTempo.
14.3.3.2
Tempo Service Description
Table 14-4.
Tempo Service Methods
Associated Function Pointers & Methods Used by Default
// Typical Use:
pAT91->OpenCtlTempo(...);
// Default Method:
AT91S_TempoStatus AT91F_OpenCtlTempo(
AT91PS_CtlTempo pCtlTempo,
void const *pTempoTimer)
Description
Member of AT91S_RomBoot structure.
Corresponds to the Open Service Method for the Tempo
Service.
Input Parameters:
Pointer on a Control Tempo Object.
Pointer on a System Timer Descriptor Structure.
Output Parameters:
Returns 0 if OpenCtrlTempo successful.
Returns 1 if not.
// Typical Use:
AT91S_CtlTempo ctlTempo;
ctlTempo.CtlTempoStart(...);
// Default Method:
AT91S_TempoStatus AT91F_STStart(void *
pTimer)
Member of AT91S_CtlTempo structure.
Start of the Hardware System Timer associated.
Input Parameters:
Pointer on a Void Parameter corresponding to a System Timer
Descriptor Structure.
Output Parameters:
Returns 2.
// Typical Use:
AT91S_CtlTempo ctlTempo;
ctlTempo.CtlTempoIsStart(...);
// Default Method:
AT91S_TempoStatus AT91F_STIsStart(
Member of AT91S_CtlTempo structure.
Input Parameters:
Pointer on a Control Tempo Object.
Output Parameters:
Returns the Status Register of the System Timer.
AT91PS_CtlTempo pCtrl)
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Table 14-4.
Tempo Service Methods (Continued)
Associated Function Pointers & Methods Used by Default
// Typical Use:
AT91S_CtlTempo ctlTempo;
ctlTempo.CtlTempoCreate(...);
// Default Method:
AT91S_TempoStatus AT91F_CtlTempoCreate (
AT91PS_CtlTempo pCtrl,
AT91PS_SvcTempo pTempo)
// Typical Use:
AT91S_CtlTempo ctlTempo;
ctlTempo.CtlTempoRemove(...);
// Default Method:
AT91S_TempoStatus AT91F_CtlTempoRemove
(AT91PS_CtlTempo pCtrl,
AT91PS_SvcTempo pTempo)
// Typical Use:
AT91S_CtlTempo ctlTempo;
ctlTempo.CtlTempoTick(...);
// Default Method:
AT91S_TempoStatus AT91F_CtlTempoTick
(AT91PS_CtlTempo pCtrl)
// Typical Use:
AT91S_SvcTempo svcTempo;
svcTempo.Start(...);
// Default Method:
AT91S_TempoStatus AT91F_SvcTempoStart (
AT91PS_SvcTempo pSvc,
unsigned int timeout,
unsigned int reload,
void (*callback) (AT91S_TempoStatus, void *),
void *pData)
// Typical Use:
AT91S_SvcTempo svcTempo;
svcTempo.Stop(...);
// Default Method:
AT91S_TempoStatus AT91F_SvcTempoStop (
Note:
Description
Member of AT91S_CtlTempo structure.
Insert a software timer in the AT91S_SvcTempo’s list.
Input Parameters:
Pointer on a Control Tempo Object.
Pointer on a Service Tempo Object to insert.
Output Parameters:
Returns 0 if the software tempo was created.
Returns 1 if not.
Member of AT91S_CtlTempo structure.
Remove a software timer in the list.
Input Parameters:
Pointer on a Control Tempo Object.
Pointer on a Service Tempo Object to remove.
Output Parameters:
Returns 0 if the tempo was created.
Returns 1 if not.
Member of AT91S_CtlTempo structure.
Refresh all the software timers in the list. Update their timeout
and check if callbacks have to be launched. So, for example, this
function has to be used when the hardware timer starts a new
periodic interrupt if period interval timer is used.
Input Parameters:
Pointer on a Control Tempo Object.
Output Parameters:
Returns 1.
Member of AT91S_SvcTempo structure.
Start a software timer.
Input Parameters:
Pointer on a Service Tempo Object.
Timeout to apply.
Number of times to reload the tempo after timeout completed for
periodic execution.
Callback on a method to launch once the timeout completed.
Allows to have a hook on the current service.
Output Parameters:
Returns 1.
Member of AT91S_SvcTempo structure.
Force to stop a software timer.
Input Parameters:
Pointer on a Service Tempo Object.
Output Parameters:
Returns 1.
AT91PS_SvcTempo pSvc)
AT91S_TempoStatus corresponds to an unsigned int.
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14.3.3.3
Using the Service
The first step is to find the address of the open service method AT91F_OpenCtlTempo using
the ROM Entry Service.
Allocate one instance of AT91S_CtlTempo and AT91S_SvcTempo in the application memory
space:
// Allocate the service and the control tempo
AT91S_CtlTempo ctlTempo;
AT91S_SvcTempo svcTempo1;
Initialize the AT91S_CtlTempo instance by calling the AT91F_OpenCtlTempo function:
// Initialize service
pAT91->OpenCtlTempo(&ctlTempo, (void *) &(pAT91->SYSTIMER_DESC));
At this stage, the application can use the AT91S_CtlTempo service members.
If the application wants to overload an object member, it can be done now. For example, if
AT91F_CtlTempoCreate(&ctlTempo, &svcTempo1) method is to be replaced by the application
defined as my_CtlTempoCreate(...), the procedure is as follows:
// Overload AT91F_CtlTempoCreate
ctlTempo.CtlTempoCreate = my_CtlTempoCreate;
In most cases, initialize the AT91S_SvcTempo object by calling the AT91F_CtlTempoCreate
method of the AT91S_CtlTempo service:
// Init the svcTempo1, link it to the AT91S_CtlTempo object
ctlTempo.CtlTempoCreate(&ctlTempo, &svcTempo1);
Start the timeout by calling Start method of the svcTempo1 object. Depending on the function
parameters, either a callback is started at the end of the countdown or the status of the timeout
is checked by reading the TickTempo member of the svcTempo1 object.
// Start the timeout
svcTempo1.Start(&svcTempo1,100,0,NULL,NULL);
// Wait for the timeout of 100 (unity depends on the timer programmation)
// No repetition and no callback.
while (svcTempo1.TickTempo);
When the application needs another software timer to control a timeout, it:
• Allocates one instance of AT91S_SvcTempo in the application memory space
// Allocate the service
AT91S_SvcTempo svcTempo2;
• Initializes the AT91S_SvcTempo object calling the AT91F_CtlTempoCreate method of the
AT91S_CtlTempo service:
// Init the svcTempo2, link it to the AT91S_CtlTempo object
ctlTempo.CtlTempoCreate(&ctlTempo, &svcTempo2);
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14.3.4
14.3.4.1
Xmodem Service
Presentation
The Xmodem service is an application of the communication pipe abstract layer. This layer is
media-independent (USART, USB, etc.) and gives entry points to carry out reads and writes on
an abstract media, the pipe.
Communication Pipe Service
The pipe communication structure is a virtual structure that contains all the functions required to
read and write a buffer, regardless of the communication media and the memory management.
The pipe structure defines:
• a pointer to a communication service structure AT91PS_SvcComm
• a pointer to a buffer manager structure AT91PS_Buffer
• pointers on read and write functions
• pointers to callback functions associated to the read and write functions
The following structure defines the pipe object:
typedef struct _AT91S_Pipe
{
// A pipe is linked with a peripheral and a buffer
AT91PS_SvcComm pSvcComm;
AT91PS_Buffer
pBuffer;
// Callback functions with their arguments
void (*WriteCallback) (AT91S_PipeStatus, void *);
void (*ReadCallback)
(AT91S_PipeStatus, void *);
void *pPrivateReadData;
void *pPrivateWriteData;
// Pipe methods
AT91S_PipeStatus (*Write) (
struct _AT91S_Pipe
*pPipe,
char const *
pData,
unsigned int
size,
void
(*callback) (AT91S_PipeStatus, void *),
void
*privateData);
AT91S_PipeStatus (*Read) (
struct _AT91S_Pipe
*pPipe,
char
*pData,
unsigned int
size,
void
(*callback) (AT91S_PipeStatus, void *),
void
*privateData);
AT91S_PipeStatus (*AbortWrite) (struct _AT91S_Pipe
*pPipe);
AT91S_PipeStatus (*AbortRead) (struct _AT91S_Pipe *pPipe);
AT91S_PipeStatus (*Reset) (struct _AT91S_Pipe *pPipe);
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char (*IsWritten) (struct _AT91S_Pipe *pPipe,char const *pVoid);
char (*IsReceived) (struct _AT91S_Pipe *pPipe,char const *pVoid);
} AT91S_Pipe, *AT91PS_Pipe;
The Xmodem protocol implementation demonstrates how to use the communication pipe.
Description of the Buffer Structure
The AT91PS_Buffer is a pointer to the AT91S_Buffer structure manages the buffers. This structure embeds the following functions:
• pointers to functions that manage the read buffer
• pointers to functions that manage the write buffer
All the functions can be overloaded by the application to adapt buffer management.
A simple implementation of buffer management for the Xmodem Service is provided in the boot
ROM source code.
typedef struct _AT91S_Buffer
{
struct _AT91S_Pipe *pPipe;
void *pChild;
// Functions invoked by the pipe
AT91S_BufferStatus (*SetRdBuffer)
char *pBuffer, unsigned int Size);
(struct _AT91S_Buffer *pSBuffer,
AT91S_BufferStatus (*SetWrBuffer)
(struct _AT91S_Buffer *pSBuffer,
char const *pBuffer, unsigned int Size);
AT91S_BufferStatus (*RstRdBuffer)
(struct _AT91S_Buffer *pSBuffer);
AT91S_BufferStatus (*RstWrBuffer)
(struct _AT91S_Buffer *pSBuffer);
char (*MsgWritten)
*pBuffer);
(struct _AT91S_Buffer *pSBuffer, char const
char (*MsgRead)
*pBuffer);
(struct _AT91S_Buffer *pSBuffer, char const
// Functions invoked by the peripheral
AT91S_BufferStatus (*GetWrBuffer)
(struct _AT91S_Buffer *pSBuffer,
char const **pData, unsigned int *pSize);
AT91S_BufferStatus (*GetRdBuffer)
char **pData, unsigned int *pSize);
(struct _AT91S_Buffer *pSBuffer,
AT91S_BufferStatus (*EmptyWrBuffer)
unsigned int size);
(struct _AT91S_Buffer *pSBuffer,
AT91S_BufferStatus (*FillRdBuffer)
unsigned int size);
(struct _AT91S_Buffer *pSBuffer,
char (*IsWrEmpty)
(struct _AT91S_Buffer *pSBuffer);
char (*IsRdFull)
(struct _AT91S_Buffer *pSBuffer);
} AT91S_Buffer, *AT91PS_Buffer;
Description of the
SvcComm Structure
104
The SvcComm structure provides the interface between low-level functions and the pipe object.
It contains pointers of functions initialized to the lower level functions (e.g. SvcXmodem).
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The Xmodem Service implementation gives an example of SvcComm use.
typedef struct _AT91S_Service
{
// Methods:
AT91S_SvcCommStatus (*Reset)
(struct _AT91S_Service *pService);
AT91S_SvcCommStatus (*StartTx)(struct _AT91S_Service *pService);
AT91S_SvcCommStatus (*StartRx)(struct _AT91S_Service *pService);
AT91S_SvcCommStatus (*StopTx) (struct _AT91S_Service *pService);
AT91S_SvcCommStatus (*StopRx) (struct _AT91S_Service *pService);
char
(*TxReady)(struct _AT91S_Service *pService);
char
(*RxReady)(struct _AT91S_Service *pService);
// Data:
struct _AT91S_Buffer *pBuffer; // Link to a buffer object
void *pChild;
} AT91S_SvcComm, *AT91PS_SvcComm;
Description of the
SvcXmodem Structure
The SvcXmodem service is a reusable implementation of the Xmodem protocol. It supports only
the 128-byte packet format and provides read and write functions. The SvcXmodem structure
defines:
• a pointer to a handler initialized to readHandler or writeHandler
• a pointer to a function that processes the xmodem packet crc
• a pointer to a function that checks the packet header
• a pointer to a function that checks data
With this structure, the Xmodem protocol can be used with all media (USART, USB, etc.). Only
private methods may be overloaded to adapt the Xmodem protocol to a new media.
The default implementation of the Xmodem uses a USART to send and receive packets. Read
and write functions implement Peripheral DMA Controller facilities to reduce interrupt overhead.
It assumes the USART is initialized, the memory buffer allocated and the interrupts
programmed.
A periodic timer is required by the service to manage timeouts and the periodic transmission of
the character “C” (Refer to Xmodem protocol). This feature is provided by the Tempo Service.
The following structure defines the Xmodem Service:
typedef struct _AT91PS_SvcXmodem {
// Public Methods:
AT91S_SvcCommStatus (*Handler) (struct _AT91PS_SvcXmodem *, unsigned int);
AT91S_SvcCommStatus (*StartTx) (struct _AT91PS_SvcXmodem *, unsigned int);
AT91S_SvcCommStatus (*StopTx)
(struct _AT91PS_SvcXmodem *, unsigned int);
// Private Methods:
AT91S_SvcCommStatus (*ReadHandler)
int csr);
(struct _AT91PS_SvcXmodem *, unsigned
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AT91S_SvcCommStatus (*WriteHandler) (struct _AT91PS_SvcXmodem *, unsigned
int csr);
unsigned short
(char *ptr, unsigned int count);
(*CheckHeader)
(unsigned char currentPacket, char
(*CheckData)
(struct _AT91PS_SvcXmodem *);
char
*packet);
(*GetCrc)
char
AT91S_SvcComm
parent;
// Base class
AT91PS_USART pUsart;
AT91S_SvcTempo tempo; // Link to a AT91S_Tempo object
char
*pData;
unsigned int
dataSize;
char
packetDesc[AT91C_XMODEM_PACKET_SIZE];
unsigned char packetId;
char
packetStatus;
char
isPacketDesc;
char
eot;
// = XMODEM_DATA_STX or XMODEM_DATA_SOH
// Current packet
// end of transmition
} AT91S_SvcXmodem, *AT91PS_SvcXmodem
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AT91RM9200
14.3.4.2
Table 14-5.
Xmodem Service Description
Xmodem Service Methods
Associated Function Pointers & Methods Used by Default
// Typical Use:
Description
Member of AT91S_RomBoot structure.
Corresponds to the Open Service Method for the Xmodem
Service.
pAT91->OpenSvcXmodem(...);
// Default Method:
Input Parameters:
Pointer on SvcXmodem structure.
Pointer on a USART structure.
Pointer on a CtlTempo structure.
Output Parameters:
Returns the Xmodem Service Pointer Structure.
AT91PS_SvcComm AT91F_OpenSvcXmodem(
AT91PS_SvcXmodem pSvcXmodem,
AT91PS_USART pUsart,
AT91PS_CtlTempo
pCtlTempo)
// Typical Use:
AT91S_SvcXmodem svcXmodem;
svcXmodem.Handler(...);
// Default read handler:
AT91S_SvcCommStatus
AT91F_SvcXmodemReadHandler(AT91PS_SvcXmodem
pSvcXmodem, unsigned int csr)
// Default write handler:
Member of AT91S_SvcXmodem structure.
interrupt handler for xmodem read or write functionnalities
Input Parameters:
Pointer on a Xmodem Service Structure.
csr: usart channel status register.
Output Parameters:
Status for xmodem read or write.
AT91S_SvcCommStatus
AT91F_SvcXmodemWriteHandler(AT91PS_SvcXmodem
pSvcXmodem, unsigned int csr)
14.3.4.3
Using the Service
The following steps show how to initialize and use the Xmodem Service in an application:
Variables definitions:
AT91S_RomBoot const *pAT91; // struct containing Openservice functions
AT91S_SBuffer
sXmBuffer; // Xmodem Buffer allocation
AT91S_SvcXmodem svcXmodem; // Xmodem service structure allocation
AT91S_Pipe
xmodemPipe;// xmodem pipe communication struct
AT91S_CtlTempo
ctlTempo; // Tempo struct
AT91PS_Buffer pXmBuffer; // Pointer on a buffer structure
AT91PS_SvcComm pSvcXmodem; // Pointer on a Media Structure
Initialisations
// Call Open methods:
pAT91 = AT91C_ROM_BOOT_ADDRESS;
// OpenCtlTempo on the system timer
pAT91->OpenCtlTempo(&ctlTempo, (void *) &(pAT91->SYSTIMER_DESC));
ctlTempo.CtlTempoStart((void *) &(pAT91->SYSTIMER_DESC));
// Xmodem buffer initialisation
pXmBuffer
= pAT91->OpenSBuffer(&sXmBuffer);
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pSvcXmodem = pAT91->OpenSvcXmodem(&svcXmodem, AT91C_BASE_DBGU, &ctlTempo);
// Open communication pipe on the xmodem service
pAT91->OpenPipe(&xmodemPipe, pSvcXmodem, pXmBuffer);
// Init the DBGU peripheral
// Open PIO for DBGU
AT91F_DBGU_CfgPIO();
// Configure DBGU
AT91F_US_Configure (
(AT91PS_USART) AT91C_BASE_DBGU,
MCK,
// DBGU base address
// Master Clock
AT91C_US_ASYNC_MODE,
BAUDRATE ,
0);
// mode Register to be programmed
// baudrate to be programmed
// timeguard to be programmed
// Enable Transmitter
AT91F_US_EnableTx((AT91PS_USART) AT91C_BASE_DBGU);
// Enable Receiver
AT91F_US_EnableRx((AT91PS_USART) AT91C_BASE_DBGU);
// Initialize the Interrupt for System Timer and DBGU (shared interrupt)
// Initialize the Interrupt Source 1 for SysTimer and DBGU
AT91F_AIC_ConfigureIt(AT91C_BASE_AIC,
AT91C_ID_SYS,
AT91C_AIC_PRIOR_HIGHEST,
AT91C_AIC_SRCTYPE_INT_LEVEL_SENSITIVE,
AT91F_ASM_ST_DBGU_Handler);
// Enable SysTimer and DBGU interrupt
AT91F_AIC_EnableIt(AT91C_BASE_AIC, AT91C_ID_SYS);
xmodemPipe.Read(&xmodemPipe, (char *) BASE_LOAD_ADDRESS, MEMORY_SIZE,
XmodemProtocol, (void *) BASE_LOAD_ADDRESS);
14.3.5
14.3.5.1
DataFlash Service
Presentation
The DataFlash Service allows the Serial Peripheral Interface (SPI) to support several Serial
DataFlash and DataFlash Cards for reading, programming and erasing operations.
This service is based on SPI interrupts that are managed by a specific handler. It also uses the
corresponding PDC registers.
For more information on the commands available in the DataFlash Service, refer to the relevant
DataFlash documentation.
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AT91RM9200
14.3.5.2
Table 14-6.
DataFlash Service Description
DataFlash Service Methods
Associated Function Pointers & Methods Used by Default
// Typical Use:
pAT91->OpenSvcDataFlash(...);
// Default Method:
AT91PS_SvcDataFlash AT91F_OpenSvcDataFlash (
const AT91PS_PMC pApmc,
AT91PS_SvcDataFlash pSvcDataFlash)
// Typical Use:
AT91S_SvcDataFlash svcDataFlash;
svcDataFlash.Handler(...);
// Default Method:
void AT91F_DataFlashHandler(
AT91PS_SvcDataFlash pSvcDataFlash,
unsigned int status)
// Typical Use:
AT91S_SvcDataFlash svcDataFlash;
svcDataFlash.Status(...);
// Default Method:
AT91S_SvcDataFlashStatus
AT91F_DataFlashGetStatus(AT91PS_DataflashDes
c pDesc)
// Typical Use:
AT91S_SvcDataFlash svcDataFlash;
svcDataFlash.AbortCommand(...);
// Default Method:
void
AT91F_DataFlashAbortCommand(AT91PS_Dataflash
Desc pDesc)
Description
Member of AT91S_RomBoot structure.
Corresponds to the Open Service Method for the DataFlash
Service.
Input Parameters:
Pointer on a PMC Register Description Structure.
Pointer on a DataFlash Service Structure.
Output Parameters:
Returns the DataFlash Service Pointer Structure.
Member of AT91S_SvcDataFlash structure.
SPI Fixed Peripheral C interrupt handler.
Input Parameters:
Pointer on a DataFlash Service Structure.
Status: corresponds to the interruptions detected and validated
on SPI (SPI Status Register masked by SPI Mask Register).
Has to be put in the Interrupt handler for SPI.
Output Parameters:
None.
Member of AT91S_SvcDataFlash structure.
Read the status register of the DataFlash.
Input Parameters:
Pointer on a DataFlash Descriptor Structure (member of the
service structure).
Output Parameters:
Returns 0 if DataFlash is Busy.
Returns 1 if DataFlash is Ready.
Member of AT91S_SvcDataFlash structure
Allows to reset PDC & Interrupts.
Input Parameters:
Pointer on a DataFlash Descriptor Structure (member of the
service structure).
Output Parameters:
None.
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Table 14-6.
DataFlash Service Methods (Continued)
Associated Function Pointers & Methods Used by Default
Description
// Typical Use:
AT91S_SvcDataFlash svcDataFlash;
svcDataFlash.PageRead(...);
// Default Method:
AT91S_SvcDataFlashStatus
AT91F_DataFlashPageRead (
AT91PS_SvcDataFlash pSvcDataFlash,
unsigned int src,
unsigned char *dataBuffer,
Member of AT91S_SvcDataFlash structure
Read a Page in DataFlash.
Input Parameters:
Pointer on DataFlash Service Structure.
DataFlash address.
Data buffer destination pointer.
Number of bytes to read.
Output Parameters:
Returns 0 if DataFlash is Busy.
Returns 1 if DataFlash Ready.
int sizeToRead )
// Typical Use:
AT91S_SvcDataFlash svcDataFlash;
svcDataFlash.ContinuousRead(...);
// Default Method:
AT91S_SvcDataFlashStatus
AT91F_DataFlashContinuousRead (
AT91PS_SvcDataFlash pSvcDataFlash,
int src,
unsigned char *dataBuffer,
int sizeToRead )
// Typical Use:
AT91S_SvcDataFlash svcDataFlash;
svcDataFlash.ReadBuffer(...);
// Default Method:
AT91S_SvcDataFlashStatus
AT91F_DataFlashReadBuffer (
AT91PS_SvcDataFlash pSvcDataFlash,
unsigned char BufferCommand,
unsigned int bufferAddress,
unsigned char *dataBuffer,
int sizeToRead )
110
Member of AT91S_SvcDataFlash structure.
Continuous Stream Read.
Input Parameters:
Pointer on DataFlash Service Structure.
DataFlash address.
Data buffer destination pointer.
Number of bytes to read.
Output Parameters:
Returns 0 if DataFlash is Busy.
Returns 1 if DataFlash is Ready.
Member of AT91S_SvcDataFlash structure.
Read the Internal DataFlash SRAM Buffer 1 or 2.
Input Parameters:
Pointer on DataFlash Service Structure.
Choose Internal DataFlash Buffer 1 or 2 command.
DataFlash address.
Data buffer destination pointer.
Number of bytes to read.
Output Parameters:
Returns 0 if DataFlash is Busy.
Returns 1 if DataFlash is Ready.
Returns 4 if DataFlash Bad Command.
Returns 5 if DataFlash Bad Address.
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table 14-6.
DataFlash Service Methods (Continued)
Associated Function Pointers & Methods Used by Default
Description
// Typical Use:
AT91S_SvcDataFlash svcDataFlash;
svcDataFlash.MainMemoryToBufferTransfert(...
);
// Default Method:
AT91S_SvcDataFlashStatus
AT91F_MainMemoryToBufferTransfert(
AT91PS_SvcDataFlash pSvcDataFlash,
unsigned char BufferCommand,
unsigned int page)
// Typical Use:
AT91S_SvcDataFlash svcDataFlash;
svcDataFlash.PagePgmBuf(...);
// Default Method:
AT91S_SvcDataFlashStatus
AT91F_DataFlashPagePgmBuf(
AT91PS_SvcDataFlash pSvcDataFlash,
unsigned char BufferCommand,
unsigned char *src,
unsigned int dest,
unsigned int SizeToWrite)
// Typical Use:
AT91S_SvcDataFlash svcDataFlash;
svcDataFlash.WriteBuffer(...);
// Default Method:
AT91S_SvcDataFlashStatus
AT91F_DataFlashWriteBuffer (
AT91PS_SvcDataFlash pSvcDataFlash,
unsigned char BufferCommand,
unsigned char *dataBuffer,
unsigned int bufferAddress,
int SizeToWrite )
Member of AT91S_SvcDataFlash structure
Read a Page in the Internal SRAM Buffer 1 or 2.
Input Parameters:
Pointer on DataFlash Service Structure.
Choose Internal DataFlash Buffer 1 or 2 command.
Page to read.
Output Parameters:
Returns 0 if DataFlash is Busy.
Returns 1 if DataFlash is Ready.
Returns 4 if DataFlash Bad Command.
Member of AT91S_SvcDataFlash structure
Page Program through Internal SRAM Buffer 1 or 2.
Input Parameters:
Pointer on DataFlash Service Structure.
Choose Internal DataFlash Buffer 1 or 2 command.
Source buffer.
DataFlash destination address.
Number of bytes to write.
Output Parameters:
Returns 0 if DataFlash is Busy.
Returns 1 if DataFlash is Ready.
Returns 4 if DataFlash Bad Command.
Member of AT91S_SvcDataFlash structure.
Write data to the Internal SRAM buffer 1 or 2.
Input Parameters:
Pointer on DataFlash Service Structure.
Choose Internal DataFlash Buffer 1 or 2 command.
Pointer on data buffer to write.
Address in the internal buffer.
Number of bytes to write.
Output Parameters:
Returns 0 if DataFlash is Busy.
Returns 1 if DataFlash is Ready.
Returns 4 if DataFlash Bad Command.
Returns 5 if DataFlash Bad Address.
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Table 14-6.
DataFlash Service Methods (Continued)
Associated Function Pointers & Methods Used by Default
Description
// Typical Use:
AT91S_SvcDataFlash svcDataFlash;
svcDataFlash.WriteBufferToMain(...);
// Default Method:
AT91S_SvcDataFlashStatus
AT91F_WriteBufferToMain (
AT91PS_SvcDataFlash pSvcDataFlash,
unsigned char BufferCommand,
unsigned int dest )
// Typical Use:
AT91S_SvcDataFlash svcDataFlash;
svcDataFlash.PageErase(...);
// Default Method:
AT91S_SvcDataFlashStatus AT91F_PageErase (
AT91PS_SvcDataFlash pSvcDataFlash,
unsigned int PageNumber)
// Typical Use:
AT91S_SvcDataFlash svcDataFlash;
svcDataFlash.BlockErase(...);
// Default Method:
AT91S_SvcDataFlashStatus AT91F_BlockErase (
AT91PS_SvcDataFlash pSvcDataFlash,
unsigned int BlockNumber )
// Typical Use:
AT91S_SvcDataFlash svcDataFlash;
svcDataFlash.MainMemoryToBufferCompare(...);
// Default Method:
AT91S_SvcDataFlashStatus
AT91F_MainMemoryToBufferCompare(
AT91PS_SvcDataFlash pSvcDataFlash,
unsigned char BufferCommand,
unsigned int page)
Note:
112
Member of AT91S_SvcDataFlash structure.
Write Internal Buffer to the DataFlash Main Memory.
Input Parameters:
Pointer on DataFlash Service Structure.
Choose Internal DataFlash Buffer 1 or 2 command.
Main memory address on DataFlash.
Output Parameters:
Returns 0 if DataFlash is Busy.
Returns 1 if DataFlash is Ready.
Member of AT91S_SvcDataFlash structure.
Erase a page in DataFlash.
Input Parameters:
Pointer on a Service DataFlash Object.
Page to erase.
Output Parameters:
Returns 0 if DataFlash is Busy.
Returns 1 if DataFlash Ready.
Member of AT91S_SvcDataFlash structure.
Erase a block of 8 pages.
Input Parameters:
Pointer on a Service DataFlash Object.
Block to erase.
Output Parameters:
Returns 0 if DataFlash is Busy.
Returns 1 if DataFlash Ready.
Member of AT91S_SvcDataFlash structure.
Compare the contents of a Page and one of the Internal SRAM
buffer.
Input Parameters:
Pointer on a Service DataFlash Object.
Internal SRAM DataFlash Buffer to compare command.
Page to compare.
Output Parameters:
Returns 0 if DataFlash is Busy.
Returns 1 if DataFlash Ready.
Returns 4 if DataFlash Bad Command.
AT91S_SvcDataFlashStatus corresponds to an unsigned int.
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
14.3.5.3
Using the Service
The first step is to find the address of the open service method AT91F_OpenSvcDataFlash using
the ROM Entry Service.
1. Allocate one instance of AT91S_SvcDataFlash and AT91S_Dataflash in the application
memory space:
// Allocate the service and a device structure.
AT91S_SvcDataFlash svcDataFlash;
AT91S_Dataflash Device; // member of AT91S_SvcDataFlash service
Then initialize the AT91S_SvcDataFlash instance by calling the AT91F_OpenSvcDataFlash
function:
// Initialize service
pAT91->OpenSvcDataFlash (AT91C_BASE_PMC, &svcDataFlash);
2. Initialize the SPI Interrupt:
// Initialize the SPI Interrupt
at91_irq_open ( AT91C_BASE_AIC,AT91C_ID_SPI,3,
AT91C_AIC_SRCTYPE_INT_LEVEL_SENSITIVE
,AT91F_spi_asm_handler);
3. Configure the DataFlash structure with its correct features and link it to the device
structure in the AT91S_SvcDataFlash service structure:
// Example with an ATMEL AT45DB321B DataFlash
Device.pages_number = 8192;
Device.pages_size = 528;
Device.page_offset = 10;
Device.byte_mask = 0x300;
// Link to the service structure
svcDataFlash.pDevice = &Device;
4. Now the different methods can be used. Following is an example of a Page Read of 528
bytes on page 50:
// Result of the read operation in RxBufferDataFlash
unsigned char RxBufferDataFlash[528];
svcDataFlash.PageRead(&svcDataFlash,
(50*528),RxBufferDataFlash,528);
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14.3.6
CRC Service
14.3.6.1
Presentation
This “service” differs from the preceding ones in that it is structured differently: it is composed of
an array and some methods directly accessible via the AT91S_RomBoot structure.
14.3.6.2
CRC Service Description
Table 14-7.
CRC Service Description
Methods and Array Available
// Typical Use:
pAT91->CRC32(...);
// Default Method:
void CalculateCrc32(
const unsigned char *address,
unsigned int size,
unsigned int *crc)
// Typical Use:
pAT91->CRC16(...);
// Default Method:
void CalculateCrc16(
const unsigned char *address,
unsigned int size,
unsigned short *crc)
// Typical Use:
pAT91->CRCHDLC(...);
// Default Method:
void CalculateCrcHdlc(
const unsigned char *address,
unsigned int size,
unsigned short *crc)
// Typical Use:
pAT91->CRCCCITT(...);
// Default Method:
void CalculateCrc16ccitt(
const unsigned char *address,
unsigned int size,
unsigned short *crc)
114
Description
This function provides a table driven 32bit CRC generation for
byte data. This CRC is known as the CCITT CRC32.
Input Parameters:
Pointer on the data buffer.
The size of this buffer.
A pointer on the result of the CRC.
Output Parameters:
None.
This function provides a table driven 16bit CRC generation for
byte data. This CRC is calculated with the POLYNOME 0x8005
Input Parameters:
Pointer on the data buffer.
The size of this buffer.
A pointer on the result of the CRC.
Output Parameters:
None.
This function provides a table driven 16bit CRC generation for
byte data. This CRC is known as the HDLC CRC.
Input Parameters:
Pointer on the data buffer.
The size of this buffer.
A pointer on the result of the CRC.
Output Parameters:
None.
This function provides a table driven 16bit CRC generation for
byte data. This CRC is known as the CCITT CRC16
(POLYNOME = 0x1021).
Input Parameters:
Pointer on the data buffer.
The size of this buffer.
A pointer on the result of the CRC.
Output Parameters:
None.
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table 14-7.
CRC Service Description (Continued)
Methods and Array Available
Description
// Typical Use:
char reverse_byte;
reverse_byte = pAT91>Bit_Reverse_Array[...];
Bit Reverse Array: array which allows to reverse one octet.
Frequently used in mathematical algorithms.
Used for example in the CRC16 calculation.
// Array Embedded:
const unsigned char bit_rev[256]
14.3.6.3
Using the Service
Compute the CRC16 CCITT of a 256-byte buffer and save it in the crc16 variable:
// Compute CRC16 CCITT
unsigned char BufferToCompute[256];
short crc16;
... (BufferToCompute Treatment)
pAT91->CRCCCITT(&BufferToCompute,256,&crc16);
14.3.7
Sine Service
14.3.7.1
Presentation
This “service” differs from the preceding one in that it is structured differently: it is composed of
an array and a method directly accessible through the AT91S_RomBoot structure.
14.3.7.2
Table 14-8.
Sine Service Description
Sine Service Description
Method and Array Available
// Typical Use:
pAT91->Sine(...);
// Default Method:
short AT91F_Sinus(int step)
Description
This function returns the amplitude coded on 16 bits, of a sine
waveform for a given step.
Input Parameters:
Step of the sine. Corresponds to the precision of the amplitude
calculation. Depends on the Sine Array used. Here, the array has
256 values (thus 256 steps) of amplitude for 180 degrees.
Output Parameters:
Amplitude of the sine waveform.
// Typical Use:
short sinus;
sinus = pAT91->SineTab[...];
Sine Array with a resolution of 256 values for 180 degrees.
// Array Embedded:
const short AT91C_SINUS180_TAB[256]
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AT91RM9200
15. AT91RM9200 Reset Controller
15.1
Overview
This chapter describes the AT91RM9200 reset signals and how to use them in order to assure
correct operation of the device.
The AT91RM9200 has two reset input lines called NRST and NTRST. Each line provides,
respectively:
• Initialization of the User Interface registers (defined in the user interface of each peripheral)
and:
– Sample the signals needed at bootup
– Compel the processor to fetch the next instruction at address zero.
• Initialization of the embedded ICE TAP controller.
The NRST signal must be considered as the System Reset signal and the reader must take care
when designing the logic to drive this reset signal. NTRST is typically used by the hardware
debug interface which uses the In-Circuit Emulator unit and Initializes it without affecting the normal operation of the ARM® processor. This line shall also be driven by an on board logic.
Both NRST and NTRST are active low signals that asynchronously reset the logic in the
AT91RM92000.
15.1.1
15.1.1.1
Reset Conditions
NRST Conditions
NRST is the active low reset input. When power is first applied to the system, a power-on reset
(also denominated as “cold” reset) must be applied to the AT91RM9200. During this transient
state, it is mandatory to hold the reset signal low long enough for the power supply to reach a
working nominal level and for the oscillator to reach a stable operating frequency. Typically,
these features are provided by every power supply supervisor which, under a threshold voltage
limit, the electrical environment is considered as not nominal. Power-up is not the only event to
be considered as power-down or a brownout are also occurrences that assert the NRST signal.
The threshold voltage must be selected according to the minimum operating voltage of the
AT91RM9200 power supply lines marked as VDD in Figure 15-1. (See Section 37.2 ”DC Characteristics” on page 632.)
The choice of the reset holding delay depends on the start-up time of the low frequency oscillator as shown below in Figure 15-1. (See Section 37.4.1 ”32 kHz Oscillator Characteristics” on
page 633.)
Figure 15-1. Cold Reset and Oscillator Start-up relationship
(1)
VDD
XIN32
VDD(min)
Oscillator Stabilization
after Power-Up
NRST
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1768I–ATARM–09-Jul-09
Note:
1. VDD is applicable to VDDIOM, VDDIOP, VDDPLL, VDDOSC and VDDCORE
NRST can also be asserted in circumstances other than the power-up sequence, such as a
manual command. This assertion can be performed asynchronously, but exit from reset is synchronized internally to the default active clock. During normal operation, NRST must be active
for a minimum delay time to ensure correct behavior. See Figure 15-2 and Table 15-1.
Table 15-1.
Reset Minimum Pulse Width
Symbol
Parameter
RST1
NRST Minimum Pulse Width
Min. Pulse Width
Unit
92
µs
Figure 15-2. NRST assertion
RST1
NRST
15.1.1.2
NTRST Assertion
As with the NRST signal, at power-up, the NTRST signal must be valid while the power supply
has not obtained the minimum recommended working level. A clock on TCK is not required to
validate this reset request.
As with the NRST signal, NTRST can also be asserted in circumstances other than the powerup sequence, such as a manual command or an ICE Interface action. This assertion and deassertion can be performed asynchronously but must be active for a minimum delay time. (See
Section 38.3 ”JTAG/ICE Timings” on page 657.)
15.1.2
15.1.2.1
Reset Management
System Reset
The system reset functionality is provided through the NRST signal.
This Reset signal is used to compel the microcontroller unit to assume a set of initial conditions:
• Sample the Boot Mode Select (BMS) logical state.
• Restore the default states (default values) of the user interface.
• Require the processor to perform the next instruction fetch from address zero.
With the exception of the program counter and the Current Program Status Register, the processor’s registers do not have defined reset states. When the microcontroller’s NRST input is
asserted, the processor immediately stops execution of the current instruction independently of
the clock.
The system reset circuitry must take two types of reset requests into account:
• The cold reset needed for the power-up sequence.
• The user reset request.
Both have the same effect but can have different assertion time requirements regarding the
NRST pin. In fact, the cold reset assertion has to overlap the start-up time of the system. The
user reset request requires a shorter assertion delay time than does cold reset.
15.1.2.2
118
Test Access Port (TAP) Reset
Test Access Port (TAP) reset functionality is provided through the NTRST signal.
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
The NTRST control pin initializes the selected TAP controller. The TAP controller involved in this
reset is determined according to the initial logical state applied on the JTAGSEL pin after the last
valid NRST.
In Boundary Scan Mode, after a NTRST assertion, the IDCODE instruction is set onto the output
of the instruction register in the Test-Logic-Reset controller state.
Otherwise, in ICE Mode, the reset action is as follows:
•
The core exits from Debug Mode.
•
The IDCORE instruction is requested.
In either Boundary Scan or ICE Mode a reset can be performed from the same or different circuitry, as shown in Figure 15-3 below, upon system reset at power-up or upon user request.
Figure 15-3. Separate or Common Reset Management
Reset
Controller
Reset
Controller
NTRST
NTRST
Reset
Controller
NRST
AT91RM9200
(1)
Notes:
NRST
AT91RM9200
(2)
1. NRST and NTRST handling in Debug Mode during development.
2. NRST and NTRST handling during production.
In order to benefit the most regarding the separation of NRST and NTRST during the Debug
phase of development, the user must independently manage both signals as shown in example
(1) of Figure 15-3 above. However, once Debug is completed, both signals are easily managed
together during production as shown in example (2) of Figure 15-3 above.
15.1.3
Required Features for the Reset Controller
The following table presents the features required of a reset controller in order to obtain an optimal system with the AT91RM9200 processor.
Table 15-2.
Reset Controller Functions Synthesis
Feature
Description
Power Supply Monitoring
Overlaps the transient state of the system during power-up/down and brownout.
Reset Active Timeout
Period
Overlaps the start-up time of the boot-up oscillator by holding the reset signal during this delay.
Manual Reset Command
Asserts the reset signal from a logic command and holds the reset signal with a shorter delay than that
of the “Reset Active Timeout Period”.
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AT91RM9200
16. Memory Controller(MC)
16.1
Overview
The Memory Controller (MC) manages the ASB bus and controls access by up to four masters.
It features a bus arbiter and an address decoder that splits the 4G bytes of address space into
areas to access the embedded SRAM and ROM, the embedded peripherals and the external
memories through the External Bus Interface (EBI). It also features an abort status and a misalignment detector to assist in application debug.
The Memory Controller allows booting from the embedded ROM or from an external non-volatile
memory connected to the Chip Select 0 of the EBI. The Remap command switches addressing
of the ARM vectors (0x0 - 0x20) on the embedded SRAM.
Key Features of the AT91RM9200 Memory Controller are:
• Programmable Bus Arbiter Handling Four Masters
– Internal Bus is Shared by ARM920T, PDC, USB Host Port and Ethernet MAC
Masters
– Each Master Can Be Assigned a Priority Between 0 and 7
• Address Decoder Provides Selection For
– Eight External 256-Mbyte Memory Areas
– Four Internal 1-Mbyte Memory Areas
– One 256-Mbyte Embedded Peripheral Area
• Boot Mode Select Option
– Non-volatile Boot Memory Can Be Internal or External
– Selection is Made By BMS Pin Sampled at Reset
• Abort Status Registers
– Source, Type and All Parameters of the Access Leading to an Abort are Saved
• Misalignment Detector
– Alignment Checking of All Data Accesses
– Abort Generation in Case of Misalignment
• Remap Command
– Provides Remapping of an Internal SRAM in Place of the Boot NVM
121
1768I–ATARM–09-Jul-09
16.2
Block Diagram
Figure 16-1. Memory Controller Block Diagram
Memory Controller
ASB
ARM920T
Processor
Abort
Internal
Memories
Abort
Status
Address
Decoder
BMS
EMAC
DMA
Bus
Arbiter
Misalignment
Detector
External
Bus
Interface
UHP
DMA
User
Interface
Peripheral
Data
Controller
APB
Bridge
AIC
Peripheral 0
Peripheral 1
Memory
Controller
Interrupt
APB
From Master
to Slave
Peripheral N
122
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1768I–ATARM–09-Jul-09
AT91RM9200
16.3
Functional Description
The Memory Controller (MC) handles the internal ASB bus and arbitrates the accesses of up to
four masters.
It is made up of:
• A bus arbiter
• An address decoder
• An abort status
• A misalignment detector
The Memory Controller handles only little-endian mode accesses. All masters must work in littleendian mode only.
16.3.1
Bus Arbiter
The Memory Controller has a user-programmable bus arbiter. Each master can be assigned a
priority between 0 and 7, where 7 is the highest level. The bus arbiter is programmed in the register MC_MPR (Master Priority Register).
The same priority level can be assigned to more than one master. If requests occur from two
masters having the same priority level, the following default priority is used by the bus arbiter to
determine the first to serve: Master 0, Master 1, Master 2, Master 3.
The masters are:
• the ARM920T as the Master 0
• the Peripheral DMA Controller as the Master 1
• the USB Host Port as the Master 2
• the Ethernet MAC as the Master 3
16.3.2
Address Decoder
The Memory Controller features an Address Decoder that first decodes the four highest bits of
the 32-bit address bus and defines 11 separate areas:
• One 256-Mbyte address space for the internal memories
• Eight 256-Mbyte address spaces, each assigned to one of the eight chip select lines of the
External Bus Interface
• One 256-Mbyte address space reserved for the embedded peripherals
• An undefined address space of 1536M bytes that returns an Abort if accessed
123
1768I–ATARM–09-Jul-09
16.3.2.1
External Memory Areas
Figure 16-2 shows the assignment of the 256-Mbyte memory areas.
Figure 16-2. External Memory Areas
256M Bytes
0x0000 0000
Internal Memories
0x0FFF FFFF
256M Bytes
0x1000 0000
Chip Select 0
0x1FFF FFFF
256M Bytes
0x2000 0000
Chip Select 1
0x2FFF FFFF
256M Bytes
0x3000 0000
Chip Select 2
0x3FFF FFFF
0x4000 0000
256M Bytes
256M Bytes
Chip Select 3
0x4FFF FFFF
0x5000 0000
Chip Select 4
EBI
External
Bus
Interface
0x5FFF FFFF
256M Bytes
0x6000 0000
Chip Select 5
0x6FFF FFFF
256M Bytes
0x7000 0000
Chip Select 6
0x7FFF FFFF
256M Bytes
0x8000 0000
Chip Select 7
0x8FFF FFFF
0x9000 0000
Undefined
(Abort)
6 x 256M Bytes
1,536M Bytes
0xEFFF FFFF
256M Bytes
0xF000 0000
Peripherals
0xFFFF FFFF
16.3.2.2
Internal Memory Mapping
Within the Internal Memory address space, the Address Decoder of the Memory Controller
decodes eight more address bits to allocate 1-Mbyte address spaces for the embedded
memories.
The allocated memories are accessed all along the 1-Mbyte address space and so are repeated
n times within this address space, n equaling 1M byte divided by the size of the memory.
When the address of the access is undefined within the internal memory area, i.e. over the
address 0x0040 0000, the Address Decoder returns an Abort to the master.
124
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AT91RM9200
Figure 16-3. Internal Memory Mapping After Remap
0x0000 0000
Internal Memory Area 0
1M Byte
Internal Memory Area 1
Internal ROM
1M Byte
Internal Memory Area 2
Internal SRAM
1M Byte
Internal Memory Area 3
USB Host Port
1M Byte
0x000F FFFF
0x0010 0000
0x001F FFFF
0x0020 0000
256M bytes
0x002F FFFF
0x0030 0000
0x003F FFFF
0x0040 0000
Undefined Area
(Abort)
252M bytes
0x0FFF FFFF
16.3.2.3
Internal Memory Area 0
Depending on the BMS pin state at reset and as a function of the remap command, the memory
mapped at address 0x0 is different. Before execution of the remap command the on-chip ROM
(BMS = 1) or the 16-bit non-volatile memory connected to external chip select zero (BMS = 0) is
mapped into Internal Memory Area 0. After the remap command, the internal SRAM at address
0x0020 0000 is mapped into Internal Memory Area 0. The memory mapped into Internal Memory Area 0 is accessible in both its original location and at address 0x0.
The first 32 bytes of Internal Memory Area 0 contain the ARM processor exception vectors.
Table 16-1.
Internal Memory Area Depending on BMS and the Remap Command
Before Remap
BMS State
Internal Memory Area 0
16.3.2.4
1
Internal ROM
After Remap
0
External Memory Area 0
X
Internal SRAM
Boot Mode Select
The BMS pin state allows the device to boot out of an internal ROM or out of an external 16-bit
memory connected on the signal NCS0. The input level on the BMS pin during the last 2 clock
cycles before the reset selects the type of boot memory according to the following conditions:
• If high, the Internal ROM, which is generally mapped within the Internal Memory Area 1, is
also accessible through the Internal Memory Area 0
• If low, the External Memory Area 0, which is generally accessible from address 0x10000000,
is also accessible through the Internal Memory Area 0.
The BMS pin is multiplexed with an I/O line. After reset, this pin can be used as any standard
PIO line.
16.3.3
Remap Command
After execution, the Remap Command causes the Internal SRAM to be accessed through the
Internal Memory Area 0.
As the ARM vectors (Reset, Abort, Data Abort, Prefetch Abort, Undefined Instruction, Interrupt,
and Fast Interrupt) are mapped from address 0x0 to address 0x20, the Remap Command allows
the user to redefine dynamically these vectors under software control.
125
1768I–ATARM–09-Jul-09
The Remap Command is accessible through the Memory Controller User Interface by writing the
MC_RCR (Remap Control Register) RCB field to one.
The Remap Command can be cancelled by writing the MC_RCR RCB field to one, which acts as
a toggling command. This allows easy debug of the user-defined boot sequence by offering a
simple way to put the chip in the same configuration as just after a reset.
Table 16-1 on page 125 is provided to summarize the effect of these two key features on the
nature of the memory mapped to the address 0x0.
16.3.4
Abort Status
There are two reasons for an abort to occur:
• an access to an undefined address
• an access to a misaligned address.
When an abort occurs, a signal is sent back to all the masters, regardless of which one has generated the access. However, only the master having generated the access leading to the abort
takes this signal into account.
The abort signal generates directly an abort on the ARM9TDMI. Note that, from the processor
perspective, an abort can also be generated by the Memory Management Unit of the ARM920T,
but this is obviously not managed by the Memory Controller and not discussed in this section.
The Peripheral DMA Controller does not handle the abort input signal (and that’s why the connection is not represented in Figure 16-1). The UHP reports an unrecoverable error in the
HcInterruptStatus register and resets its operations. The EMAC reports the Abort to the user
through the ABT bit in its Status Register, which might generate an interrupt.
To facilitate debug or for fault analysis by an operating system, the Memory Controller integrates
an Abort Status register set.
The full 32-bit wide abort address is saved in the Abort Address Status Register (MC_AASR).
Parameters of the access are saved in the Abort Status Register (MC_ASR) and include:
• the size of the request (ABTSZ field)
• the type of the access, whether it is a data read or write or a code fetch (ABTTYP field)
• whether the access is due to accessing an undefined address (UNDADD bit) or a misaligned
address (MISADD bit)
• the source of the access leading to the last abort (MST0, MST1, MST2 and MST3 bits)
• whether or not an abort occurred for each master since the last read of the register
(SVMST0, SVMST1, SVMST2 and SVMST3 bits) except if it is traced in the MST bits.
In case of Data Abort from the processor, the address of the data access is stored. This is probably the most useful, as finding which address has generated the abort would require
disassembling the instruction and full knowledge of the processor context.
However, in case of prefetch abort, the address might have changed, as the prefetch abort is
pipelined in the ARM processor. The ARM processor takes the prefetch abort into account only if
the read instruction is actually executed and it is probable that several aborts have occurred during this time. So, in this case, it is preferable to use the content of the Abort Link register of the
ARM processor.
126
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1768I–ATARM–09-Jul-09
AT91RM9200
16.3.5
Misalignment Detector
The Memory Controller features a Misalignment Detector that checks the consistency of the
accesses.
For each access, regardless of the master, the size of access and the 0 and 1 bits of the
address bus are checked. If the type of access is a word (32-bit) and the 0 and 1 bits are not 0,
or if the type of the access is a half-word (16-bit) and the 0 bit is not 0, an abort is returned to the
master and the access is cancelled. Note that the accesses of the ARM processor when it is
fetching instructions are not checked.
The misalignments are generally due to software errors leading to wrong pointer handling.
These errors are particularly difficult to detect in the debug phase.
As the requested address is saved in the Abort Status and the address of the instruction generating the misalignment is saved in the Abort Link Register of the processor, detection and
correction of this kind of software error is simplified.
16.3.6
Memory Controller Interrupt
The Memory Controller itself does not generate any interrupt. However, as indicated in Figure
16-1, the Memory Controller receives an interrupt signal from the External Bus Interface, which
might be activated in case of Refresh Error detected by the SDRAM Controller. This interrupt
signal just transits through the Memory Controller, which can neither enable/disable it nor return
its activity.
This Memory Controller interrupt signal is ORed with the other System Peripheral interrupt lines
(RTC, ST, DBGU, PMC) to provide the System Interrupt on Source 1 of the Advanced Interrupt
Controller.
127
1768I–ATARM–09-Jul-09
16.4
User Interface
Base Address: 0xFFFFFF00
AT91RM9200 Memory Controller Memory Map
Offset
Register
Name
Access
0x00
MC Remap Control Register
MC_RCR
Write-only
0x04
MC Abort Status Register
MC_ASR
Read-only
0x0
0x08
MC Abort Address Status Register
MC_AASR
Read-only
0x0
0x0C
MC Master Priority Register
MC_MPR
Read/Write
0x3210
0x10 - 0x5C
Reserved
0x60
EBI Configuration Registers
128
Reset State
See “External Bus Interface (EBI)” on page 133
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
16.4.1
MC Remap Control Register
Register Name:
MC_RCR
Access Type:
Write-only
Absolute Address:
0xFFFF FF00
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
–
–
–
–
–
–
–
RCB
• RCB: Remap Command Bit
0: No effect.
1: This Command Bit acts on a toggle basis: writing a 1 alternatively cancels and restores the remapping of the page zero
memory devices.
129
1768I–ATARM–09-Jul-09
16.4.2
MC Abort Status Register
Register Name:
MC_ASR
Access Type:
Read-only
Reset Value:
0x0
Absolute Address:
0xFFFF FF04
31
30
29
28
27
26
25
24
–
–
–
–
SVMST3
SVMST2
SVMST1
SVMST0
23
22
21
20
19
18
17
16
–
–
–
–
MST3
MST2
MST1
MST0
15
14
13
12
11
10
9
–
–
–
–
7
6
5
4
3
2
1
0
–
–
–
–
–
–
MISADD
UNDADD
ABTTYP
8
ABTSZ
• UNDADD: Undefined Address Abort Status
0: The last abort was not due to the access of an undefined address in the address space.
1: The last abort was due to the access of an undefined address in the address space.
• MISADD: Misaligned Address Abort Status
0: The last aborted access was not due to an address misalignment.
1: The last aborted access was due to an address misalignment.
• ABTSZ: Abort Size Status
ABTSZ
Abort Size
0
0
Byte
0
1
Half-word
1
0
Word
1
1
Reserved
• ABTTYP: Abort Type Status
ABTTYP
Abort Type
0
0
Data Read
0
1
Data Write
1
0
Code Fetch
1
1
Reserved
• MST0: ARM920T Abort Source
0: The last aborted access was not due to the ARM920T.
1: The last aborted access was due to the ARM920T.
130
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AT91RM9200
• MST1: PDC Abort Source
0: The last aborted access was not due to the PDC.
1: The last aborted access was due to the PDC.
• MST2: UHP Abort Source
0: The last aborted access was not due to the UHP.
1: The last aborted access was due to the UHP.
• MST3: EMAC Abort Source
0: The last aborted access was not due to the EMAC.
1: The last aborted access was due to the EMAC.
• SVMST0: Saved ARM920T Abort Source
0: No abort due to the ARM920T occurred since the last read of MC_ASR or it is notified in the bit MST0.
1: At least one abort due to the ARM920T occurred since the last read of MC_ASR.
• SVMST1: Saved PDC Abort Source
0: No abort due to the PDC occurred since the last read of MC_ASR or it is notified in the bit MST1.
1: At least one abort due to the PDC occurred since the last read of MC_ASR.
• SVMST2: Saved UHP Abort Source
0: No abort due to the UHP occurred since the last read of MC_ASR or it is notified in the bit MST2.
1: At least one abort due to the UHP occurred since the last read of MC_ASR.
• SVMST3: Saved EMAC Abort Source
0: No abort due to the EMAC occurred since the last read of MC_ASR or it is notified in the bit MST3.
1: At least one abort due to the EMAC occurred since the last read of MC_ASR.
131
1768I–ATARM–09-Jul-09
16.4.3
MC Abort Address Status Register
Register Name:
MC_AASR
Access Type:
Read-only
Reset Value:
0x0
Absolute Address:
0xFFFF FF08
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
ABTADD
23
22
21
20
ABTADD
15
14
13
12
ABTADD
7
6
5
4
ABTADD
• ABTADD: Abort Address
This field contains the address of the last aborted access.
16.4.4
MC Master Priority Register
Register Name:
MC_MPR
Access Type:
Read/Write
Reset Value:
0x3210
Absolute Address:
0xFFFF FF0C
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
MSTP3
7
6
–
5
MSTP1
–
4
3
MSTP2
2
–
1
0
MSTP0
• MSTP0: ARM920T Priority
• MSTP1: PDC Priority
• MSTP2: UHP Priority
• MSTP3: EMAC Priority
000: Lowest priority
111: Highest priority
In the case of equal priorities, Master 0 has highest and Master 3 has lowest priority.
132
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AT91RM9200
17. External Bus Interface (EBI)
17.1
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 ARM-based device. The
Static Memory, SDRAM and Burst Flash 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,
SDRAM and Burst Flash.
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 eight external devices, each assigned to eight address
spaces defined by the embedded Memory Controller. Data transfers are performed through a
16-bit or 32-bit data bus, an address bus of up to 26 bits, up to eight chip select lines (NCS[7:0])
and several control pins that are generally multiplexed between the different external Memory
Controllers.
Features of the EBI are:
• Integrates Three External Memory Controllers:
– Static Memory Controller
– SDRAM Controller
– Burst Flash Controller
• Additional Logic for NAND Flash/SmartMedia and CompactFlash Support
• Optimized External Bus:
– 16- or 32-bit Data Bus(1)
– Up to 26-bit Address Bus, Up to 64 Mbytes Addressable
– Up to 8 Chip Selects, Each Reserved for one of the Eight Memory Areas
– Optimized Pin Multiplexing to Reduce Latencies on External Memories
• Configurable Chip Select Assignment:
– Burst Flash Controller or Static Memory Controller on NCS0
– SDRAM Controller or Static Memory Controller on NCS1
– Static Memory Controller on NCS3, Optional NAND Flash/SmartMedia Support
– Static Memory Controller on NCS4 - NCS6, Optional NAND Flash/SmartMedia and
CompactFlash Support
– Static Memory Controller on NCS7
Note:
1. The 32-bit Data Bus is for SDRAM only.
133
1768I–ATARM–09-Jul-09
17.2
Block Diagram
Figure 17-1 below shows the organization of the External Bus Interface.
Figure 17-1. Organization of the External Bus Interface
External Bus Interface
Memory
Controller
D[15:0]
ASB
SDRAM
Controller
A0/NBS0
A1/NWR2/NBS2
A[15:2], A[22:18]
A16/BA0
MUX
Logic
Burst Flash
Controller
A17/BA1
NCS0/BFCS
NCS1/SDCS
NCS2
NCS3/SMCS
Static
Memory
Controller
NRD/NOE/CFOE
NWR0/NWE/CFWE
NWR1/NBS1/CFIOR
NWR3/NBS3/CFIOW
SDCK
SDCKE
RAS
CAS
SDWE
NAND Flash/
SmartMedia
Logic
SDA10
D[31:16]
PIO
A[24:23]
A25/CFRNW
CompactFlash
Logic
NCS4/CFCS
NCS5/CFCE1
NCS6/CFCE2
NCS7
Address Decoder
Chip Select
Assignor
BFCK
BFAVD
BFBAA/SMWE
BFOE
BFRDY/SMOE
User Interface
BFWE
NWAIT
APB
134
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
17.3
I/O Lines Description
Table 17-1.
I/O Lines Description
Name
Function
Type
Active Level
EBI
D[31:0]
Data Bus
I/O
A[25:0]
Address Bus
Output
SMC
NCS[7:0]
Chip Select Lines
Output
Low
NWR[1:0]
Write Signals
Output
Low
NOE
Output Enable
Output
Low
NRD
Read Signal
Output
Low
NBS1
NUB: Upper Byte Select
Output
Low
NBS0
NLB: Lower Byte Select
Output
Low
NWE
Write Enable
Output
Low
NWAIT
Wait Signal
Input
Low
EBI for CompactFlash Support
CFCE[2:1]
CompactFlash Chip Enable
Output
Low
CFOE
CompactFlash Output Enable
Output
Low
CFWE
CompactFlash Write Enable
Output
Low
CFIOR
CompactFlash I/O Read Signal
Output
Low
CFIOW
CompactFlash I/O Write Signal
Output
Low
CFRNW
CompactFlash Read Not Write Signal
Output
CFCS
CompactFlash Chip Select Line
Output
Low
EBI for NAND Flash/SmartMedia Support
SMCS
NAND Flash/Smart Media Chip Select Line
Output
Low
SMOE
NAND Flash/SmartMedia Output Enable
Output
Low
SMWE
NAND Flash/SmartMedia Write Enable
Output
Low
SDRAM Controller
SDCK
SDRAM Clock
Output
SDCKE
SDRAM Clock Enable
Output
High
SDCS
SDRAM Controller Chip Select Line
Output
Low
BA[1:0]
Bank Select
Output
SDWE
SDRAM Write Enable
Output
Low
RAS - CAS
Row and Column Signal
Output
Low
NWR[3:0]
Write Signals
Output
Low
NBS[3:0]
Byte Mask Signals
Output
Low
SDA10
SDRAM Address 10 Line
Output
135
1768I–ATARM–09-Jul-09
Table 17-1.
I/O Lines Description (Continued)
Name
Function
Type
Active Level
Burst Flash Controller
BFCK
Burst Flash Clock
Output
BFCS
Burst Flash Chip Select Line
Output
Low
BFAVD
Burst Flash Address Valid Signal
Output
Low
BFBAA
Burst Flash Address Advance Signal
Output
Low
BFOE
Burst Flash Output Enable
Output
Low
BFRDY
Burst Flash Ready Signal
Input
High
BFWE
Burst Flash Write Enable
Output
Low
The connection of some signals through the MUX logic is not direct and depends on the Memory
Controller in use at the moment.
Table 17-2 below details the connections between the three Memory Controllers and the EBI
pins.
Table 17-2.
EBI Pins and Memory Controllers I/O Line Connections
EBI Pins
SDRAMC I/O Lines
BFC I/O Lines
SMC I/O Lines
NWR1/NBS1/CFIOR
NBS1
Not Supported
NWR1/NUB
A0/NBS0
Not Supported
Not Supported
A0/NLB
A1
Not Supported
A0
A1
A[11:2]
A[9:0]
A[10:1]
A[11:2]
SDA10
A10
Not Supported
Not Supported
A12
Not Supported
A11
A12
A[14:13]
A[12:11]
A[13:12]
A[14:13]
A[25:15]
Not Supported
A[24:14]
A[25:15]
D[31:16]
D[31:16]
Not Supported
Not Supported
D[15:0]
D[15:0]
D[15:0]
D[15:0]
136
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AT91RM9200
17.4
Application Example
17.4.1
Hardware Interface
Table 17-3 below details the connections to be applied between the EBI pins and the external
devices for each Memory Controller.
Table 17-3.
EBI Pins and External Device Connections
Pins of the Interfaced Device
Pin
8-bit Static
Device
Controller
2 x 8-bit
Static
Devices
16-bit Static
Device
SMC
Burst Flash
Device
SDRAM
BFC
SDRAMC
CompactFlash
NAND Flash/
SmartMedia
SMC
D0 - D7
D0 - D7
D0 - D7
D0 - D7
D0 - D7
D0 - D7
D0 - D7
AD0 - AD7
D8 - D15
–
D8 - D15
D8 - D15
D8 - D15
D8 - D15
D8 - 15
–
D16 - D31
–
–
–
–
D16 - D31
–
–
A0/NBS0
A0
–
NLB
–
DQM0
A0
–
A1/NWR2/NBS2
A1
A0
A0
A0
DQM2
A1
–
A2 - A9
A1 - A8
A1 - A8
A1 - A8
A0 - A7
A2 - A9
–
A10
A10
A9
A9
A9
A8
A10
–
A11
A11
A10
A10
A10
A9
–
–
–
–
–
–
A10
–
–
A12
A11
A11
A11
–
–
–
A13 - A14
A12 - A13
A12 - A13
A12 - A13
A11 - A12
–
–
A15
A15
A14
A14
A14
–
–
–
A16/BA0
A16
A15
A15
A15
BA0
–
–
A17/BA1
A17
A16
A16
A16
BA1
–
–
A18 - A20
A18 - A20
A17 - A19
A17 - A19
A17 - A19
–
–
–
A21
A21
A20
A20
A20
–
–
CLE
A22
A22
A21
A21
A21
–
REG(3)
ALE
A23 - A24
A22 - A23
A22 - A23
A22 - A23
–
–
–
A2 - A9
SDA10
A12
A13 - A14
A23 - A24
(1)
A25
A25
A24
A24
A24
–
CFRNW
–
NCS0/BFCS
CS
CS
CS
CS
–
–
–
NCS1/SDCS
CS
CS
CS
–
CS
–
–
NCS2
CS
CS
CS
–
–
–
–
NCS3/SMCS
CS
CS
CS
–
–
–
–
(1)
–
NCS4/CFCS
CS
CS
CS
–
–
CFCS
NCS5/CFCE1
CS
CS
CS
–
–
CE1
–
NCS6/CFCE2
CS
CS
CS
–
–
CE2
–
NRD/NOE/CFOE
OE
OE
OE
–
–
OE
WE
–
–
WE
NWR0/NWE/CFWE
WE
WE
(5)
137
1768I–ATARM–09-Jul-09
Table 17-3.
EBI Pins and External Device Connections (Continued)
Pins of the Interfaced Device
8-bit Static
Device
Pin
Controller
2 x 8-bit
Static
Devices
16-bit Static
Device
SMC
Burst Flash
Device
SDRAM
BFC
SDRAMC
NAND Flash/
SmartMedia
CompactFlash
SMC
NWR1/NBS1/CFIOR
–
WE(5)
NUB
–
DQM1
IOR
–
NWR3/NBS3/CFIOW
–
–
–
–
DQM3
IOW
–
BFCK
–
–
–
CK
–
–
–
BFAVD
–
–
–
AVD
–
–
–
BFBAA/SMWE
–
–
–
BAA
–
–
WE
BFOE
–
–
–
OE
–
–
–
BFRDY/SMOE
–
–
–
RDY
–
–
OE
BFWE
–
–
–
WE
–
–
–
SDCK
–
–
–
–
CLK
–
–
SDCKE
–
–
–
–
CKE
–
–
RAS
–
–
–
–
RAS
–
–
CAS
–
–
–
–
CAS
–
–
SDWE
–
–
–
–
WE
–
–
NWAIT
–
–
–
–
–
WAIT
–
(2)
–
–
–
–
–
CD1 or CD2
–
Pxx(2)
–
–
–
–
–
–
CE
(2)
–
–
–
–
–
–
RDY
Pxx
Pxx
Notes:
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 PIO line.
3. The REG signal of the CompactFlash can be driven by any of the following address bits: A24, A22 to A11. For details, see
Section 17.6.6 “CompactFlash Support” on page 141.
4. NWR1 enables upper byte writes. NWR0 enables lower byte writes.
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17.4.2
Connection Examples
Figure 17-2 below shows an example of connections between the EBI and external devices.
Figure 17-2. EBI Connections to Memory Devices
EBI
D0-D31
RAS
CAS
SDCK
SDCKE
SDWE
A0/NBS0
NWR1/NBS1
A1/NWR2/NBS2
NWR3/NBS3
NRD/NOE
NWR0/NWE
D0-D7
2M x 8
SDRAM
D8-D15
D0-D7
CS
CLK
CKE
SDWE WE
RAS
CAS
DQM
NBS0
A0-A9, A11
A10
BA0
BA1
2M x 8
SDRAM
D0-D7
CS
CLK
CKE
SDWE
WE
RAS
CAS
DQM
NBS1
A2-A11, A13
SDA10
A16/BA0
A17/BA1
A0-A9, A11
A10
BA0
BA1
A2-A11, A13
SDA10
A16/BA0
A17/BA1
SDA10
A2-A15
A16/BA0
A17/BA1
A18-A25
2M x 8
SDRAM
D16-D23 D0-D7
NCS0/BFCS
NCS1/SDCS
NCS2
NCS3
NCS4
NCS5
NCS6
NCS7
CS
CLK
CKE
SDWE WE
RAS
CAS
DQM
A0-A9, A11
A10
BA0
BA1
D24-D31
2M x 8
SDRAM
D0-D7
CS
CLK
CKE
SDWE
WE
RAS
CAS
DQM
NBS3
A2-A11, A13
SDA10
A16/BA0
A17/BA1
A0-A9, A11
A10
BA0
BA1
A2-A11, A13
SDA10
A16/BA0
A17/BA1
NBS2
BFCLK
BFOE
BFWE
BFAVD
BFRDY
2M x 16
Burst Flash
D0-D15
D0-D15
A0-A20
A1-A21
CE
CLK
OE
WE
AVD
RDY
128K x 8
SRAM
D0-D7
D0-D7
A0-A16
128K x 8
SRAM
A1-A17
D8-D15
CS
NRD/NOE
A0/NWR0/NBS0
OE
WE
D0-D7
A0-A16
A1-A17
CS
NRD/NOE
NWR1/NBS1
OE
WE
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1768I–ATARM–09-Jul-09
17.5
17.5.1
Product Dependencies
I/O Lines
The pins used for interfacing the External Bus Interface may be multiplexed with the PIO lines.
The programmer must first program the PIO controller to assign the External Bus Interface pins
to their peripheral function. If I/O lines of the External Bus Interface are not used by the application, they can be used for other purposes by the PIO Controller.
17.6
Functional Description
The EBI transfers data between the internal ASB Bus (handled by the Memory Controller) 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 Burst Flash Controller (BFC)
• A chip select assignment feature that assigns an ASB address space to the external devices.
• A multiplex controller circuit that shares the pins between the different Memory Controllers.
• Programmable CompactFlash support logic
• Programmable NAND Flash /SmartMedia and support logic
17.6.1
Bus Multiplexing
The EBI offers a complete set of control signals that share the 32-bit data lines, the address
lines of up to 26 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 SDRAM Controller without
delaying the other external Memory Controller accesses. Lastly, it prevents burst accesses on
the same page of a burst Flash from being interrupted which avoids the need to restart a highlatency first access.
17.6.2
Pull-up Control
The EBI permits enabling of on-chip pull-up resistors on the data bus lines not multiplexed with
the PIO Controller lines. The pull-up resistors are enabled after reset. Setting the DBPUC bit disables the pull-up resistors on the D0 to D15 lines. Enabling the pull-up resistor on the D16 - D31
lines can be performed by programming the appropriate PIO controller.
17.6.3
Static Memory Controller
For information on the Static Memory Controller, refer to the SMC Section 18.1 “Description” on
page 155.
17.6.4
SDRAM Controller
For information on the SDRAM Controller, refer to the SDRAMC description on Section 19.1
“Overview” on page 193.
140
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17.6.5
Burst Flash Controller
For information on the Burst Flash Controller, refer to the BFC Section 20.1 “Overview” on page
215.
17.6.6
CompactFlash Support
The External Bus Interface integrates circuitry that interfaces to CompactFlash devices.
The CompactFlash logic is driven by the Static Memory Controller (SMC) on the NCS4 address
space. Programming the CS4A field of the Chip Select Assignment Register (See Section 17.8.1
”EBI Chip Select Assignment Register” on page 152.) to the appropriate value enables this logic.
Access to an external CompactFlash device is then made by accessing the address space
reserved to NCS4 (i.e., between 0x5000 0000 and 0x5FFF FFFF).
When multiplexed with CFCE1 and CFCE2 signals, the NCS5 and NCS6 signals become
unavailable. Performing an access within the address space reserved to NCS5 and NCS6 (i.e.,
between 0x6000 0000 and 0x7FFF FFFF) may lead to an unpredictable outcome.
The True IDE Mode is not supported and in I/O Mode, the signal _IOIS16 is not managed.
17.6.6.1
I/O Mode, Common Memory Mode and Attribute Memory Mode
Within the NCS4 address space, the current transfer address is used to distinguish I/O mode,
common memory mode and attribute memory mode. More precisely, the A23 bit of the transfer
address is used to select I/O Mode. Any EBI address bit not required by the CompactFlash
device (i.e., bit A24 or bits A22 to A11) can be used to separate common memory mode and
attribute memory mode. Using the A22 bit, for example, leads to the address map in Figure 17-3
below. In this figure, “i” stands for any hexadecimal digit.
Figure 17-3. Address Map Example
0x5iBF FFFF
0x5i80 0000
0x5i7F FFFF
0x5i40 0000
0x5i3F FFFF
A23 = 1
A22 = 0
I/O Mode
A23 = 0
A22 = 1
Common Memory Mode
A23 = 0
A22 = 0
Attribute Memory Mode
0x5i00 0000
Note:
17.6.6.2
In the above example, the A22 pin of the EBI can be used to drive the REG signal of the CompactFlash Device.
Read/Write Signals
In I/O mode, the CompactFlash logic drives the read and write command signals of the SMC on
CFIOR and CFIOW signals, while the CFOE and CFWE signals are deactivated. Likewise, in
common memory mode and attribute memory mode, the SMC signals are driven on the CFOE
and CFWE signals, while the CFIOR and CFIOW are deactivated. Figure 17-4 on page 142
demonstrates a schematic representation of this logic.
Attribute memory mode, common memory mode and I/O mode are supported by setting the
address setup and hold time on the NCS4 chip select to the appropriate values. For details on
these signal waveforms, please refer to: Section 18.6.5 “Setup and Hold Cycles” on page 168 of
the Static Memory Controller documentation.
141
1768I–ATARM–09-Jul-09
Figure 17-4. CompactFlash Read/Write Control Signals
External Bus Interface
SMC
CompactFlash Logic
A23
1
1
CFIOR
CFIOW
NRD_NOE
NWR0_NWE
CFOE
CFWE
1
1
17.6.6.3
Access Type
The CFCE1 and CFCE2 signals enable upper- and lower-byte access on the data bus of the
CompactFlash device in accordance with Table 17-4 below. The odd byte access on the D[7:0]
bus is only possible when the SMC is configured to drive 8-bit memory devices on the NCS4 pin.
The Chip Select Register (DBW field in Section 18.7.1 “SMC Chip Select Registers” on page
190) of the NCS4 address space must be set as shown in Table 17-4 to enable the required
access type. The CFCE1 and CFCE2 waveforms are identical to the NCS4 waveform. For
details on these waveforms and timings, refer to the Static Memory Controller Section 18.1
“Description” on page 155.
Table 17-4.
Upper- and Lower-byte Access
Access
CFCE2
CFCE1
A0
D[15:8]
D[7:0]
SMC_CSR4 (DBW)
1
0
0
Don’t Care/High Z
Even Byte
8-bit or 16-bit
1
0
1
Don’t Care/High Z
Odd Byte
8-bit
Odd Byte R/W Access
0
1
X
Odd Byte
Don’t Care/High Z
16-bit
Half-word R/W Access
0
0
X
Odd Byte
Even Byte
16-bit
Byte R/W Access
17.6.6.4
142
Multiplexing of CompactFlash Signals on EBI Pins
Table 17-5 below and Table 17-6 on page 143 illustrate the multiplexing of the CompactFlash
logic signals with other EBI signals on the EBI pins. The EBI pins in Table 17-5 are strictly dedicated to the CompactFlash interface as soon as the CS4A field of the Chip Select Assignment
Register is set (See Section 17.8.1 ”EBI Chip Select Assignment Register” on page 152.) These
pins must not be used to drive any other memory devices.
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
The EBI pins in Table 17-6 on page 143 remain shared between all memory areas when the
CompactFlash interface is enabled (CS4A = 1).
Table 17-5.
Dedicated CompactFlash Interface Multiplexing
CS4A = 1
CS4A = 0
Pins
CompactFlash Signals
EBI Signals
NCS4/CFCS
CFCS
NCS4
NCS5/CFCE1
CFCE1
NCS5
NCS6/CFCE2
CFCE2
NCS6
Table 17-6.
Shared CompactFlash Interface Multiplexing
Access to CompactFlash Device
Access to Other EBI Devices
Pins
CompactFlash Signals
EBI Signals
NOE/NRD/CFOE
CFOE
NRD/NOE
NWR0/NWE/CFWE
CFWE
NWR0/NWE
NWR1/NBS1/CFIOR
CFIOR
NWR1/NBS1
NWR3/NBS3/CFIOW
CFIOW
NWR3/NBS3
A25/CFRNW
CFRNW
A25
17.6.6.5
CompactFlash Application Example
Figure 17-5 below illustrates an example of a CompactFlash application. CFCS and CFRNW
signals are not directly connected to the CompactFlash slot, but do control the direction and the
output enable of the buffers between the EBI and the CompactFlash Device. The timing of the
CFCS signal is identical to the NCS4 signal. Moreover, 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 Static Memory Controller Section 18.1 “Description” on page 155.
143
1768I–ATARM–09-Jul-09
Figure 17-5. CompactFlash Application Example
EBI
CompactFlash Connector
D[15:0]
D[15:0]
DIR /OE
A25/CFRNW
NCS4/CFCS
_CD1
CD (PIO)
_CD2
/OE
A[10:0]
A[10:0]
A22/REG
_REG
NOE/CFOE
_OE
NWE/CFWE
_WE
NWR1/CFIOR
_IORD
NWR3/CFIOW
_IOWR
NCS5/CFE1
_CE1
NCS6/CFE2
_CE2
NWAIT
17.6.7
_WAIT
NAND Flash/ SmartMedia Support
The EBI integrates circuitry that interfaces to NAND Flash/SmartMedia devices.
The NAND Flash/SmartMedia logic is driven by the Static Memory Controller on the NCS3
address space. Programming the CS3A field in the Chip Select Assignment Register to the
appropriate value enables the NAND Flash/SmartMedia logic (See Section 17.8.1 ”EBI Chip
Select Assignment Register” on page 152.) Access to an external NAND Flash/SmartMedia
device is then made by accessing the address space reserved to NCS3 (i.e., between 0x4000
0000 and 0x4FFF FFFF).
The NAND Flash/SmartMedia Logic drives the read and write command signals of the SMC on
the SMOE and SMWE signals when the NCS3 signal is active. SMOE and SMWE are invalidated as soon as the transfer address fails to lie in the NCS3 address space. For details on
these waveforms, refer to the Static Memory Controller Section 18.1 “Description” on page 155.
The SMWE and SMOE signals are multiplexed with BFRDY and BFBAA signals of the Burst
Flash Controller. This multiplexing is controlled in the MUX logic part of the EBI by the CS3A
field of the Chip Select Assignment Register (See Section 17.8.1 ”EBI Chip Select Assignment
Register” on page 152.) This logic also controls the direction of the BFRDY/SMOE pad.
144
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AT91RM9200
Figure 17-6.
NAND Flash/SmartMedia Signal Multiplexing on EBI Pins
MUX Logic
BFC
BFRDY
BFRDY_SMOE
BFBAA
BFBAA_SMWE
NAND Flash/Smart Media
Logic
SMC
SMOE
NCS3
NRD_NOE
SMWE
NWR0_NWE
EBI User Interface
CS3A
The address latch enable and command latch enable signals on the NAND Flash/SmartMedia
device are driven by address bits A22 and A21 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/SmartMedia device are distinguished by using
their address within the NCS3 address space. The chip enable (CE) signal of the device and the
ready/busy (R/B) signals are connected to PIO lines. The CE signal then remains asserted even
when NCS3 is not selected, preventing the device from returning to standby mode. Some functional limitation with the supported burst Flash device will occur when the NAND
Flash/SmartMedia device is activated due to the fact that the SMOE and SMWE signals are multiplexed with BFRDY and BFBAA signals respectively.
145
1768I–ATARM–09-Jul-09
Figure 17-7. NAND Flash/SmartMedia Application Example
D[7:0]
AD[7:0]
A[22:21]
ALE
CLE
NCS3/SMCS
Not Connected
EBI
NAND Flash/SmartMedia
BFBAA/SMWE
BFRDY/SMOE
146
NWE
NOE
PIO
CE
PIO
R/B
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
17.7
Implementation Examples
17.7.1
16-bit SDRAM
17.7.1.1
Hardware Configuration
17.7.1.2
Software Configuration
The following configuration has to be performed:
• Assign the EBI CS1 to the SDRAM controller by setting the bit EBI_CS1A in the EBI Chip
Select Assignment Register located in the bus matrix memory space
• Initialize the SDRAM Controller accordingly to SDRAM device and system bus frequency.
The Data Bus Width is to be programmed to 16 bits.
The SDRAM initialization sequence is described in the “SDRAM Device Initialization” part of the
SDRAM controller.
147
1768I–ATARM–09-Jul-09
17.7.2
32-bit SDRAM
17.7.2.1
Hardware Configuration
17.7.2.2
Software Configuration
The following configuration has to be performed:
• Assign the EBI CS1 to the SDRAM controller by setting the bit EBI_CS1A in the EBI Chip
Select Assignment Register located in the bus matrix memory space
• Initialize the SDRAM Controller accordingly to SDRAM device and system bus frequency.
The Data Bus Width is to be programmed to 32 bits. The data lines D[16..31] are multiplexed
with PIO lines and thus the dedicated PIOs must be programmed in peripheral mode in the PIO
controller.
The SDRAM initialization sequence is described in the “SDRAM Device Initialization” part of the
SDRAM controller.
148
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17.7.3
NOR Flash on NCS0
17.7.3.1
Hardware Configuration
17.7.3.2
Software Configuration
The default configuration for the Static Memory Controller, byte select mode, 16-bit data bus,
Read/Write controlled by Chip Select, allows boot on a 16-bit non-volatile memory at slow clock.
For other configurations, configure Static Memory Controller CS0 Setup, Pulse, Cycle and Mode
accordingly to Flash timings and system bus frequency.
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1768I–ATARM–09-Jul-09
17.7.4
Compact Flash
17.7.4.1
Hardware Configuration
17.7.4.2
Software Configuration
The following configuration has to be performed:
• Assign the EBI CS4 to the CompactFlash slot by setting the bit EBI_CS4A in the EBI Chip
Select Assignment Register located in the Bus Matrix memory space.
• The address line A23 is to select I/O (A23=1) or Memory mode (A23=0) and the address line
A22 for REG function.
• A23, CFRNW, CFCS0, CFCE1 and CFCE2 signals are multiplexed with PIO lines and thus
the dedicated PIOs must be programmed in peripheral mode in the PIO controller
• Configure a PIO line as an output for CFRST and two others as an input for CFIRQ and
CARD DETECT functions respectively.
• Configure SMC CS4 Setup, Pulse, Cycle and Mode accordingly to Compact Flash timings
and system bus frequency.
150
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17.8
External Bus Interface (EBI) User Interface
AT91RM9200 EBI User Interface Base Address: 0xFFFF FF60
Table 17-7.
External Bus Interface Memory Map
Offset
Register
Name
Access
Reset State
EBI_CSA
Read/Write
0x0
EBI_CFGR
Read/Write
0x0
0x00
Chip Select Assignment Register
0x04
Configuration Register
0x08
Reserved
–
0x0C
Reserved
–
0x10 - 0x2C
SMC User Interface
0x30 - 0x5C
SDRAMC User Interface
0x60
0x64 - 0x9C
BFC User Interface
(See Section 18.7 ”Static Memory Controller (SMC) User Interface” on page
189.)
(See Section 19.7 ”SDRAM Controller (SDRAMC) User Interface” on page 205.)
(See Section 20.7 ”Burst Flash Controller (BFC) User Interface” on page 227.)
Reserved
151
1768I–ATARM–09-Jul-09
17.8.1
EBI Chip Select Assignment Register
Register Name:
EBI_CSA
Access Type:
Read/Write
Reset Value:
0x0
Offset:
0x0
Absolute Address:
0xFFFF FF60
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
CS4A
3
CS3A
2
–
1
CS1A
0
CS0A
• CS0A: Chip Select 0 Assignment
0 = Chip Select 0 is assigned to the Static Memory Controller.
1 = Chip Select 0 is assigned to the Burst Flash Controller.
• CS1A: Chip Select 1 Assignment
0 = Chip Select 1 is assigned to the Static Memory Controller.
1 = Chip Select 1 is assigned to the SDRAM Controller.
• CS3A: Chip Select 3 Assignment
0 = Chip Select 3 is only assigned to the Static Memory Controller and NCS3 behaves as defined by the SMC.
1 = Chip Select 3 is assigned to the Static Memory Controller and the NAND Flash/SmartMedia Logic is activated.
• CS4A: Chip Select 4 Assignment
0 = Chip Select 4 is assigned to the Static Memory Controller and NCS4, NCS5 and NCS6 behave as defined by the SMC.
1 = Chip Select 4 is assigned to the Static Memory Controller and the CompactFlash Logic is activated.
Accessing the address space reserved to NCS5 and NCS6 may lead to an unpredictable outcome.
152
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17.8.2
EBI Configuration Register
Register Name:
EBI_CFGR
Access Type:
Read/Write
Reset Value:
0x0
Offset:
0x04
Absolute Address:
0xFFFF FF64
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
DBPUC
• DBPUC: Data Bus Pull-Up Configuration
0 = [D15:0] Data Bus bits are internally pulled-up to the VDDIOM power supply.
1 = [D15:0] Data Bus bits are not internally pulled-up.
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AT91RM9200
18. Static Memory Controller (SMC)
18.1
Description
The Static Memory Controller (SMC) generates the signals that control the access to external
static memory or peripheral devices. The SMC is fully programmable. It has eight chip selects
and a 23-bit address bus. The 16-bit data bus can be configured to interface with 8- or 16-bit
external devices. Separate read and write control signals allow for direct memory and peripheral
interfacing. The SMC supports different access protocols allowing single clock cycle memory
accesses. It also provides an external wait request capability.
18.2
Block Diagram
Figure 18-1. Static Memory Controller Block Diagram
PIO
Controller
SMC
Memory
Controller
SMC
Chip Select
NCS[7:0]
NRD
NWR0/NWE
NWR1/NUB
A0/NLB
PMC
A[22:1]
MCK
D[15:0]
NWAIT
User Interface
APB
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AT91RM9200
18.3
I/O Lines Description
Table 18-1.
I/O Lines Description
Name
Description
Type
Active Level
NCS[7:0]
Static Memory Controller Chip Select Lines
Output
Low
NRD
Read Signal
Output
Low
NWR0/NWE
Write 0/Write Enable Signal
Output
Low
NWR1/NUB
Write 1/Upper Byte Select Signal
Output
Low
A0/NLB
Address Bit 0/Lower Byte Select Signal
Output
Low
A[22:1]
Address Bus
Output
D[15:0]
Data Bus
NWAIT
External Wait Signal
18.4
I/O
Input
Low
Multiplexed Signals
Table 18-2.
Static Memory Controller Multiplexed Signals
Multiplexed Signals
Related Function
A0
NLB
8-bit or 16-bit data bus, see 18.6.1.3 “Data Bus Width” on page 158.
NWR0
NWE
Byte-write or byte-select access, see 18.6.2.1 “Write Access Type” on page 159.
NWR1
NUB
Byte-write or byte-select access, see 18.6.2.1 “Write Access Type” on page 159.
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AT91RM9200
18.5
Product Dependencies
18.5.1
I/O Lines
The pins used for interfacing the Static Memory Controller may be multiplexed with the PIO
lines. The programmer must first program the PIO controller to assign the Static Memory Controller pins to their peripheral function. If I/O lines of the Static Memory Controller are not used by
the application, they can be used for other purposes by the PIO Controller.
18.6
Functional Description
18.6.1
18.6.1.1
External Memory Interface
External Memory Mapping
The memory map is defined by hardware and associates the internal 32-bit address space with
the external 23-bit address bus. Note that A[22:0] is only significant for 8-bit memory. A[22:1] is
used for 16-bit memory. If the physical memory device is smaller than the page size, it wraps
around and appears to be repeated within the page. The SMC correctly handles any valid
access to the memory device within the page. See Figure 18-2.
Figure 18-2. Case of an External Memory Smaller than Page Size
Base + 4M Bytes
1M Byte Device
Hi
Repeat 3
Low
Base + 3M Bytes
1M Byte Device
Memory
Map
Hi
Repeat 2
Low
Base + 2M Bytes
1M Byte Device
Hi
Repeat 1
Low
Base + 1M Byte
1M Byte Device
Hi
Low
Base
18.6.1.2
Chip Select Lines
The Static Memory Controller provides up to eight chip select lines: NCS0 to NCS7.
157
1768I–ATARM–09-Jul-09
Figure 18-3. Memory Connections for Eight External Devices (1)
NCS[7:0]
NCS7
NRD
SMC
NCS6
NWR[1:0]
NCS5
A[22:0]
NCS4
D[15:0]
NCS3
NCS2
NCS1
NCS0
Memory Enable
Memory Enable
Memory Enable
Memory Enable
Memory Enable
Memory Enable
Memory Enable
Memory Enable
Output Enable
Write Enable
A[22:0]
8 or 16
Note:
D[15:0] or D[7:0]
1. The maximum address space per device is 8 Mbytes.
18.6.1.3
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 DBW field in the SMC_CSR for the corresponding chip select. See “SMC Chip Select Registers” on page 190.
Figure 18-4 shows how to connect a 512K x 8-bit memory on NCS2 (DBW = 10).
Figure 18-4. Memory Connection for an 8-bit Data Path Device
D[7:0]
D[7:0]
D[15:8]
A[22:1]
SMC
A0
A[22:1]
A0
NWR1
NWR0
NRD
NCS2
Write Enable
Output Enable
Memory Enable
Figure 18-5 shows how to connect a 512K x 16-bit memory on NCS2 (DBW = 01).
158
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AT91RM9200
Figure 18-5. Memory Connection for a 16-bit Data Path Device
SMC
D[7:0]
D[7:0]
D[15:8]
D[15:8]
A[22:1]
A[22:0]
NLB
Low Byte Enable
NUB
High Byte Enable
NWE
Write Enable
NRD
Output Enable
NCS2
18.6.2
18.6.2.1
Memory Enable
Write Access
Write Access Type
Each chip select with a 16-bit data bus can operate with one of two different types of write
access:
• Byte Write Access supports two byte write and a single read signal.
• Byte Select Access selects upper and/or lower byte with two byte select lines, and separate
read and write signals.
This option is controlled by the BAT field in the SMC_CSR for the corresponding chip select.
See “SMC Chip Select Registers” on page 190.
Byte Write Access
Byte Write Access is used to connect 2 x 8-bit devices as a 16-bit memory page.
• The signal A0/NLB is not used.
• The signal NWR1/NUB is used as NWR1 and enables upper byte writes.
• The signal NWR0/NWE is used as NWR0 and enables lower byte writes.
• The signal NRD enables half-word and byte reads.
Figure 18-6 shows how to connect two 512K x 8-bit devices in parallel on NCS2 (BAT = 0)
159
1768I–ATARM–09-Jul-09
Figure 18-6. Memory Connection for 2 x 8-bit Data Path Devices
D[7:0]
D[7:0]
D[15:8]
A[22:1]
SMC
A[18:0]
A0
NWR1
NWR0
Write Enable
NRD
Read Enable
NCS2
Memory Enable
D[15:8]
A[18:0]
Write Enable
Read Enable
Memory Enable
18.6.2.2
Byte Select Access
Byte Select Access is used to connect 16-bit devices in a memory page.
• The signal A0/NLB is used as NLB and enables the lower byte for both read and write
operations.
• The signal NWR1/NUB is used as NUB and enables the upper byte for both read and write
operations.
• The signal NWR0/NWE is used as NWE and enables writing for byte or half-word.
• The signal NRD enables reading for byte or half-word.
Figure 18-7 shows how to connect a 16-bit device with byte and half-word access (e.g., SRAM
device type) on NCS2 (BAT = 1).
Figure 18-7. Connection to a 16-bit Data Path Device with Byte and Half-word Access
SMC
D[7:0]
D[7:0]
D[15:8]
D[15:8]
A[19:1]
A[18:0]
NLB
Low Byte Enable
NUB
High Byte Enable
NWE
Write Enable
NRD
Output Enable
NCS2
Memory Enable
Figure 18-8 shows how to connect a 16-bit device without byte access (e.g., Flash device type)
on NCS2 (BAT = 1).
160
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Figure 18-8. Connection to a 16-bit Data Path Device without Byte Write Capability
SMC
D[7:0]
D[7:0]
D[15:8]
D[15:8]
A[19:1]
A[18:0]
NLB
NUB
18.6.2.3
NWE
Write Enable
NRD
Output Enable
NCS2
Memory Enable
Write Data Hold Time
During write cycles, data output becomes valid after the rising edge of MCK and remains valid
after the rising edge of NWE. During a write access, the data remain on the bus 1/2 period of
MCK after the rising edge of NWE. See Figure 18-9 and Figure 18-10.
Figure 18-9. Write Access with 0 Wait State
MCK
A[22:0]
NCS
NWE
D[15:0]
Figure 18-10. Write Access with 1 Wait State
MCK
A[22:0]
NCS
NWE
D[15:0]
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18.6.3
18.6.3.1
Read Access
Read Protocols
The SMC provides two alternative protocols for external memory read accesses: standard and
early read. The difference between the two protocols lies in the behavior of the NRD signal.
For write accesses, in both protocols, NWE has the same behavior. In the second half of the
master clock cycle, NWE always goes low (see Figure 18-18 on page 167).
The protocol is selected by the DRP field in SMC_CSR (See “SMC Chip Select Registers” on
page 190.). Standard read protocol is the default protocol after reset.
Note:
18.6.3.2
In the following waveforms and descriptions NWE represents NWE, NWR0 and NWR1 unless
NWR0 and NWR1 are otherwise represented. In addition, NCS represents NCS[7:0] (see 18.5.1
“I/O Lines” on page 157, Table 18-1 and Table 18-2).
Standard Read Protocol
Standard read protocol implements a read cycle during which NRD and NWE are similar. Both
are active during the second half of the clock cycle. The first half of the clock cycle allows time to
ensure completion of the previous access as well as the output of address lines and NCS before
the read cycle begins.
During a standard read protocol, NCS is set low and address lines are valid at the beginning of
the external memory access, while NRD goes low only in the second half of the master clock
cycle to avoid bus conflict. See Figure 18-11.
Figure 18-11. Standard Read Protocol
MCK
A[22:0]
NCS
NRD
D[15:0]
18.6.3.3
162
Early Read Protocol
Early read protocol provides more time for a read access from the memory by asserting NRD at
the beginning of the clock cycle. In the case of successive read cycles in the same memory,
NRD remains active continuously. Since a read cycle normally limits the speed of operation of
the external memory system, early read protocol can allow a faster clock frequency to be used.
However, an extra wait state is required in some cases to avoid contentions on the external bus.
AT91RM9200
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AT91RM9200
Figure 18-12. Early Read Protocol
MCK
A[22:0]
NCS
NRD
D[15:0]
18.6.4
Wait State Management
The SMC can automatically insert wait states. The different types of wait states managed are
listed below:
• Standard wait states
• External wait states
• Data float wait states
• Chip select change wait states
• Early Read wait states
18.6.4.1
Standard Wait States
Each chip select can be programmed to insert one or more wait states during an access on the
corresponding memory area. This is done by setting the WSEN field in the corresponding
SMC_CSR (“SMC Chip Select Registers” on page 190). The number of cycles to insert is programmed in the NWS field in the same register.
Below is the correspondence between the number of standard wait states programmed and the
number of clock cycles during which the NWE pulse is held low:
0 wait states
1/2 clock cycle
1 wait state
1 clock cycle
For each additional wait state programmed, an additional cycle is added.
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Figure 18-13. One Standard Wait State Access
1 Wait State Access
MCK
A[22:0]
NCS
NWE
NRD
Notes:
(1)
(2)
1. Early Read Protocol
2. Standard Read Protocol
18.6.4.2
External Wait States
The NWAIT input pin is used to insert wait states beyond the maximum standard wait states programmable or in addition to. If NWAIT is asserted low, then the SMC adds a wait state and no
changes are made to the output signals, the internal counters or the state. When NWAIT is deasserted, the SMC completes the access sequence.
WARNING: Asserting NWAIT low stops the core’s clock and thus stops program execution.
The input of the NWAIT signal is an asynchronous input. To avoid any metastability problems,
NWAIT is synchronized before using it. This operation results in a two-cycle delay.
NWS must be programmed as a function of synchronization time and delay between NWAIT falling and control signals falling (NRD/NWE), otherwise SMC will not function correctly.
NWS ≥ Wait Delay from nrd/nwe + external_nwait Synchronization Delay + 1
Note:
Where external NWAIT synchronization is equal to 2 cycles.
The minimum value for NWS if NWAIT is used, is 3.
WARNING: If NWAIT is asserted during a setup or hold timing, the SMC does not function
correctly.
164
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Figure 18-14. NWAIT Behavior in Read Access [NWS = 3]
MCK
A[22:0]
NWAIT
NWAIT
internally synchronized
NRD
NCS
(2)
(1)
Wait Delay from NRD
Notes:
NWAIT
Synchronization Delay
1. Early Read Protocol
2. Standard Read Protocol
Figure 18-15. NWAIT Behavior in Write Access [NWS = 3]
MCK
A[22:0]
NWAIT
NWAIT
internally synchronized
NWE
D[15:0]
Wait Delay
from NWE
18.6.4.3
NWAIT
Synchronization Delay
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 write access or a
read access to a different external memory.
The Data Float Output Time (tDF) for each external memory device is programmed in the TDF
field of the SMC_CSR register for the corresponding chip select (“SMC Chip Select Registers”
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1768I–ATARM–09-Jul-09
on page 190). The value of TDF indicates the number of data float wait cycles (between 0 and
15) to be inserted 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.
To ensure that the external memory system is not accessed while it is still busy, the SMC keeps
track of the programmed external data float time during internal accesses.
Internal memory accesses and consecutive read accesses to the same external memory do not
add data float wait states.
Figure 18-16. Data Float Output Delay
MCK
A[22:0]
NCS
NRD
(1)
(2)
tDF
D[15:0]
Notes:
1. Early Read Protocol
2. Standard Read Protocol
18.6.4.4
166
Chip Select Change Wait State
A chip select wait state is automatically inserted when consecutive accesses are made to two
different external memories (if no other type of wait state has already been inserted). If a wait
state has already been inserted (e.g., data float wait state), then no more wait states are added.
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Figure 18-17. Chip Select Wait State
Mem 1
Chip Select Wait
Mem 2
MCK
A[22:0]
addr Mem 2
addr Mem 1
NCS1
NCS2
NRD
(1)
(2)
NWE
Notes:
1. Early Read Protocol
2. Standard Read Protocol
18.6.4.5
Early Read Wait State
In early read protocol, an early read wait state is automatically inserted when an external write
cycle is followed by a read cycle to allow time for the write cycle to end before the subsequent
read cycle begins (see Figure 18-18). This wait state is generated in addition to any other programmed wait states (i.e., data float wait state).
No wait state is added when a read cycle is followed by a write cycle, between consecutive
accesses of the same type, or between external and internal memory accesses.
Figure 18-18. Early Read Wait States
Write Cycle
Early Read Wait
Read Cycle
MCK
A[22:0]
NCS
NRD
NWE
D[15:0]
167
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18.6.5
Setup and Hold Cycles
The SMC allows some memory devices to be interfaced with different setup, hold and pulse
delays. These parameters are programmable and define the timing of each portion of the read
and write cycles. However, it is not possible to use this feature in early read protocol.
If an attempt is made to program the setup parameter as not equal to zero and the hold parameter as equal to zero with WSEN = 0 (0 standard wait state), the SMC does not operate correctly.
If consecutive accesses are made to two different external memories and the second memory is
programmed with setup cycles, then no chip select change wait state is inserted (see Figure 1823 on page 170).
When a data float wait state (tDF) is programmed on the first memory bank and when the second
memory bank is programmed with setup cycles, the SMC behaves as follows:
• If the number of tDF is higher or equal to the number of setup cycles, the number of setup
cycles inserted is equal to 0 (see Figure 18-24 on page 170).
• If the number of the setup cycle is higher than the number of tDF, the number of tDF inserted is
0 (see Figure 18-25 on page 171).
18.6.5.1
Read Access
The read cycle can be divided into a setup, a pulse length and a hold. The setup parameter can
have a value between 1.5 and 7.5 clock cycles, the hold parameter between 0 and 7 clock
cycles and the pulse length between 1.5 and 128.5 clock cycles, by increments of one.
Figure 18-19. Read Access with Setup and Hold
MCK
A[22:0]
NRD
NRD Setup
Pulse Length
NRD Hold
Figure 18-20. Read Access with Setup
MCK
A[22:0]
NRD
NRD Setup
168
Pulse Length
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AT91RM9200
18.6.5.2
Write Access
The write cycle can be divided into a setup, a pulse length and a hold. The setup parameter can
have a value between 1.5 and 7.5 clock cycles, the hold parameter between 0.5 and 7 clock
cycles and the pulse length between 1 and 128 clock cycles by increments of one.
Figure 18-21. Write Access with Setup and Hold
MCK
A[22:0]
NWE
D[15:0]
NWR Setup
Pulse Length
NWR Hold
Figure 18-22. Write Access with Setup
MCK
A[22:0]
NWE
D[15:0]
NWR Setup
Pulse Length
NWR
Hold
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1768I–ATARM–09-Jul-09
18.6.5.3
Data Float Wait States with Setup Cycles
Figure 18-23. Consecutive Accesses with Setup Programmed on the Second Access
Setup
MCK
A[22:0]
NCS1
NCS2
NWE
NRD
Figure 18-24. First Access with Data Float Wait States (TDF = 2) and Second Access with Setup (NRDSETUP = 1)
Setup
MCK
A[22:0]
NCS1
NCS2
NRD
D[15:0]
Data Float Time
170
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Figure 18-25. First Access with Data Float Wait States (TDF = 2) and Second Access with Setup (NRDSETUP = 3)
Setup
MCK
A[22:0]
NCS1
NCS2
NRD
D[15:0]
Data Float Time
18.6.6
LCD Interface Mode
The SMC can be configured to work with an external liquid crystal display (LCD) controller by
setting the ACSS (Address to Chip Select Setup) bit in the SMC_CSR registers (“SMC Chip
Select Registers” on page 190).
In LCD mode, NCS is shortened by one/two/three clock cycles at the leading and trailing edges,
providing positive address setup and hold. For read accesses, the data is latched in the SMC
when NCS is raised at the end of the access.
Additionally, WSEN must be set and NWS programmed with a value of two or more superior to
ACSS. In LCD mode, it is not recommended to use RWHOLD or RWSETUP. If the above conditions are not satisfied, SMC does not operate correctly.
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Figure 18-26. Read Access in LCD Interface Mode
MCK
A[22:0]
NRD
NCS
ACSS
ACSS
Data from LCD Controller
ACSS = 3, NWEN = 1, NWS = 10
Figure 18-27. Write Access in LCD Interface Mode
MCK
A[22:0]
NWE
NCS
ACCS
ACCS
D[15:0]
ACCS = 2, NWEN = 1, NWS = 10
18.6.7
18.6.7.1
172
Memory Access Waveforms
Read Accesses in Standard and Early Protocols
Figure 18-28 on page 173 through Figure 18-31 on page 176 show examples of the alternatives
for external memory read protocol.
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AT91RM9200
Figure 18-28. Standard Read Protocol without tDF
Read Mem 1
Write Mem 1
Read Mem 1
Read Mem 2
Write Mem 2
Read Mem 2
MCK
A[22:0]
NRD
NWE
NCS1
Chip Select
Change Wait
NCS2
D[15:0] (Mem 1)
D[15:0] (to write)
tWHDX
tWHDX
D[15:0] (Mem 2)
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1768I–ATARM–09-Jul-09
Figure 18-29. Early Read Protocol without tDF
Read
Mem 1
Write
Mem 1
Early Read
Wait Cycle
Read
Mem 1
Read
Mem 2
Write
Mem 2
Early Read
Wait Cycle
Read
Mem 2
MCK
A[22:0]
NRD
NWE
NCS1
Chip Select
Change Wait
NCS2
D[15:0] (Mem 1)
D[15:0] (to write)
tWHDX
Long tWHDX
D[15:0] (Mem 2)
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Figure 18-30. Standard Read Protocol with tDF
Read Mem 1
Data
Float Wait
Write
Mem 1
Read Mem 1
Data
Float Wait
Read
Mem 2
Read Mem 2
Write
Mem 2
Write
Mem 2
Data
Float Wait
MCK
A[22:0]
NRD
NWE
NCS1
NCS2
tDF
D[15:0]
(Mem 1)
tDF
(tDF = 1)
(tDF = 1)
D[15:0]
(to write)
tWHDX
D[15:0]
(Mem 2)
tDF
(tDF = 2)
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1768I–ATARM–09-Jul-09
Figure 18-31. Early Read Protocol with tDF
Read Mem 1
Data
Float Wait
Write
Mem 1
Early
Read Wait
Read Mem 1
Data
Float Wait
Read
Mem 2
Read Mem 2
Data
Float Wait
Write
Mem 2
Write
Mem 2
MCK
A[22:0]
NRD
NWE
NCS1
NCS2
tDF
tDF
D[15:0]
(Mem 1)
D[15:0]
(to write)
tDF (tDF = 2)
D[15:0]
(Mem 2)
18.6.7.2
176
Accesses with Setup and Hold
Figure 18-32 and Figure 18-33 show an example of read and write accesses with Setup and
Hold Cycles.
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Figure 18-32. Read Accesses in Standard Read Protocol with Setup and Hold(1)
MCK
A[22:1]
00d2b
00028
00d2c
A0/NLB
NRD
NWR0/NWE
NWR1/NUB
Setup
Setup
Hold
Hold
NCS
D[15:0]
Note:
e59f
0001
0002
1. Read access, memory data bus width = 8, RWSETUP = 1, RWHOLD = 1,WSEN= 1, NWS = 0
Figure 18-33. Write Accesses with Setup and Hold(1)
MCK
A[22:1]
00082
008cb
008cc
A0/NLB
NRD
NWR0/NWE
NWR1/NUB
NCS
D[15:0] 3000
Setup
Note:
0606
0605
e3a0
Hold
Setup
Hold
1. Write access, memory data bus width = 8, RWSETUP = 1, RWHOLD = 1, WSEN = 1, NWS = 0
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18.6.7.3
Accesses Using NWAIT Input Signal
Figure 18-34 on page 178 through Figure 18-37 on page 181 show examples of accesses using
NWAIT.
Figure 18-34. Write Access using NWAIT in Byte Select Type Access(1)
Chip Select
Wait
MCK
NWAIT
NWAIT
internally
synchronized
A[22:1]
000008A
NRD
NWR0/NWE
A0/NLB
NWR1/NUB
NCS
D[15:0]
1312
Wait Delay Falling
from NWR0/NWE
Note:
178
1. Write access memory, data bus width = 16 bits, WSEN = 1, NWS = 6
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Figure 18-35. Write Access using NWAIT in Byte Write Type Access(1)
Chip Select
Wait
MCK
NWAIT
NWAIT
internally
synchronized
A[22:1]
000008C
A0/NLB
NRD
NWR0/NWE
NWR1/NUB
NCS
D[15:0]
1716
Wait Delay Falling from NWR0/NWE/NWR1/NUB
Note:
1. Write access memory, data bus width = 16 bits, WSEN = 1, NWS = 5
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Figure 18-36. Write Access using NWAIT(1)
Chip Select
Wait
MCK
NWAIT
NWAIT
internally
synchronized
A[22:1]
0000033
A0/NLB
NRD
NWR0/NWE
NWR1/NUB
NCS
0403
D[15:0]
Wait Delay Falling from NWR0/NWE
Note:
180
1. Write access memory, data bus width = 8 bits, WSEN = 1, NWS = 4
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Figure 18-37. Read Access in Standard Protocol using NWAIT(1)
MCK
NWAIT
NWAIT
internally
synchronized
0002C44
A[22:1]
A0/NLB
NRD
NWR0/NWE
NWR1/NUB
NCS
D[15:0]
0003
Wait Delay Falling from NRD/NOE
Note:
1. Read access, memory data bus width = 16, NWS = 5, WSEN = 1
18.6.7.4
Memory Access Example Waveforms
Figure 18-38 on page 182 through Figure 18-44 on page 188 show the waveforms for read and
write accesses to the various associated external memory devices. The configurations
described are shown in Table 18-3.
Table 18-3.
Memory Access Waveforms
Figure Number
Number of Wait
States
Bus Width
Size of Data Transfer
Figure 18-38
0
16
Word
Figure 18-39
1
16
Word
Figure 18-40
1
16
Half-word
Figure 18-41
0
8
Word
Figure 18-42
1
8
Half-word
Figure 18-43
1
8
Byte
Figure 18-44
0
16
Byte
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Figure 18-38. 0 Wait State, 16-bit Bus Width, Word Transfer
MCK
A[22:1]
addr+1
addr
NCS
NLB
NUB
Read Access
· Standard Read Protocol
NRD
D[15:0]
B2 B1
B 4 B3
· Early Read Protocol
NRD
D[15:0]
B2 B1
B4 B3
Write Access
· Byte Write/
Byte Select Option
NWE
D[15:0]
182
B2 B1
B 4 B3
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Figure 18-39. 1 Wait State, 16-bit Bus Width, Word Transfer
1 Wait State
1 Wait State
MCK
A[22:1]
addr
addr+1
NCS
NLB
NUB
Read Access
· Standard Read Protocol
NRD
B2 B 1
D[15:0]
B 4 B3
· Early Read Protocol
NRD
D[15:0]
B2 B1
B4 B3
Write Access
· Byte Write/
Byte Select Option
NWE
D[15:0]
B2 B1
B4B3
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Figure 18-40. 1 Wait State, 16-bit Bus Width, Half-Word Transfer
1 Wait State
MCK
A[22:1]
NCS
NLB
NUB
Read Access
· Standard Read Protocol
NRD
D[15:0]
B2 B 1
· Early Read Protocol
NRD
D[15:0]
B2 B1
Write Access
· Byte Write/
Byte Select Option
NWE
D[15:0]
184
B2 B1
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Figure 18-41. 0 Wait State, 8-bit Bus Width, Word Transfer
MCK
A[22:0]
addr+1
addr
addr+2
addr+3
NCS
Read Access
· Standard Read Protocol
NRD
D[15:0]
X B1
X B2
X B3
X B4
X B1
X B2
X B3
X B4
X B1
X B2
X B3
X B4
· Early Read Protocol
NRD
D[15:0]
Write Access
NWR0
NWR1
D[15:0]
185
1768I–ATARM–09-Jul-09
Figure 18-42. 1 Wait State, 8-bit Bus Width, Half-Word Transfer
1 Wait State
1 Wait State
MCK
A[22:0]
Addr
Addr+1
NCS
Read Access
· Standard Read, Protocol
NRD
D[15:0]
X B1
X B2
· Early Read Protocol
NRD
D[15:0]
X B1
X B2
X B1
X B2
Write Access
NWR0
NWR1
D[15:0]
186
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Figure 18-43. 1 Wait State, 8-bit Bus Width, Byte Transfer
1 Wait State
MCK
A[22:0]
NCS
Read Access
· Standard Read Protocol
NRD
D[15:0]
XB1
· Early Read Protocol
NRD
D[15:0]
X B1
Write Access
NWR0
NWR1
D[15:0]
X B1
187
1768I–ATARM–09-Jul-09
Figure 18-44. 0 Wait State, 16-bit Bus Width, Byte Transfer
MCK
A[22:1]
addr X X X 0
addr X X X 0
Internal Address Bus
addr X X X 0
addr X X X 1
NCS
NLB
NUB
Read Access
· Standard Read Protocol
NRD
D[15:0]
X B1
B2X
· Early Read Protocol
NRD
D[15:0]
XB1
B2X
B1B1
B2B2
Write Access
· Byte
Write Option
NWR0
NWR1
D[15:0]
· Byte Select Option
NWE
188
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18.7
Static Memory Controller (SMC) User Interface
The Static Memory Controller is programmed using the registers listed in Table 18-4. Eight Chip Select Registers
(SMC_CSR0 to SMC_CSR7) are used to program the parameters for the individual external memories.
Table 18-4.
Register Mapping
Offset
Register
Name
Access
Reset
0x00
SMC Chip Select Register 0
SMC_CSR0
Read-write
0x00002000
0x04
SMC Chip Select Register 1
SMC_CSR1
Read-write
0x00002000
0x08
SMC Chip Select Register 2
SMC_CSR2
Read-write
0x00002000
0x0C
SMC Chip Select Register 3
SMC_CSR3
Read-write
0x00002000
0x10
SMC Chip Select Register 4
SMC_CSR4
Read-write
0x00002000
0x14
SMC Chip Select Register 5
SMC_CSR5
Read-write
0x00002000
0x18
SMC Chip Select Register 6
SMC_CSR6
Read-write
0x00002000
0x1C
SMC Chip Select Register 7
SMC_CSR7
Read-write
0x00002000
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18.7.1
SMC Chip Select Registers
Register Name:
SMC_CSR0..SMC_CSR7
Access Type:
Read-write
Reset Value:
See Table 18-4 on page 189
31
–
30
29
RWHOLD
28
27
–
26
25
RWSETUP
24
23
–
22
–
21
–
20
–
19
–
18
–
17
16
15
DRP
14
13
12
BAT
11
10
7
WSEN
6
4
3
NWS
DBW
5
ACSS
9
8
1
0
TDF
2
• NWS: Number of Wait States
This field defines the Read and Write signal pulse length from 1 cycle up to 128 cycles.
Note:
When WSEN i 0, NWS will be read to 0 whichever the previous programmed value should be.
NWS Field
NRD Pulse Length
Standard Read Protocol
NRD Pulse Length
Early Read Protocol
NWR Pulse Length
Don’t Care
½ cycle
1 cycle
½ cycle
1
0
1 + ½ cycles
2 cycles
1 cycle
2
1
2 + ½ cycles
3 cycles
2 cycles
X+1
Up to X = 127
X + 1+ ½ cycles
X + 2 cycles
X + 1 cycle
Number of Wait States
0
Note:
(1)
1. Assuming WSEN Field = 0.
• WSEN: Wait State Enable
0: Wait states are disabled.
1: Wait states are enabled.
• TDF: Data Float Time
The external bus is marked occupied and cannot be used by another chip select during TDF cycles. Up to 15 cycles can be
defined and represents the time allowed for the data output to go to high impedance after the memory is disabled.
• BAT: Byte Access Type
This field is used only if DBW defines a 16-bit data bus.
0: Chip select line is connected to two 8-bit wide devices.
1: Chip select line is connected to a 16-bit wide device.
190
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• DBW: Data Bus Width
DBW
Data Bus Width
0
0
Reserved
0
1
16-bit
1
0
8-bit
1
1
Reserved
• DRP: Data Read Protocol
0: Standard Read Protocol is used.
1: Early Read Protocol is used.
• ACSS: Address to Chip Select Setup
ACSS
Chip Select Waveform
0
0
Standard, asserted at the beginning of the access and deasserted at the end.
0
1
One cycle less at the beginning and the end of the access.
1
0
Two cycles less at the beginning and the end of the access.
1
1
Three cycles less at the beginning and the end of the access.
• RWSETUP: Read and Write Signal Setup Time
See definition and description below.
• RWHOLD: Read and Write Signal Hold Time
See definition and description below.
RWSETUP(1) (5)
NRD Setup
NWR Setup
RWHOLD(1) (4) (5)
NRD Hold
NWR Hold
0
0
0
½ cycle(2)or
0 cycles(3)
½ cycle
0
0
0
0
½ cycle
0
0
1
1 + ½ cycles
1 + ½ cycles
0
0
1
1 cycles
1 cycle
0
1
0
2 + ½ cycles
2 + ½ cycles
0
1
0
2 cycles
2 cycles
0
1
1
3 + ½ cycles
3 + ½ cycles
0
1
1
3 cycles
3 cycles
1
0
0
4 + ½ cycles
4 + ½ cycles
1
0
0
4 cycles
4 cycles
1
0
1
5 + ½ cycles
5 + ½ cycles
1
0
1
5 cycles
5 cycles
1
1
0
6 + ½ cycles
6 + ½ cycles
1
1
0
6 cycles
6 cycles
1
1
1
7 + ½ cycles
7 + ½ cycles
1
1
1
7 cycles
7 cycles
Notes:
1. For a visual description, please refer to “Setup and Hold Cycles” on page 168 and the diagrams in Figure 18-45 and Figure
18-46 and Figure 18-47 on page 192.
2. In Standard Read Protocol.
3. In Early Read Protocol. (It is not possible to use the parameters RWSETUP or RWHOLD in this mode.)
4. When the ECC Controller is used, RWHOLD must be programmed to 1 at least.
5. If an attempt is made to program the setup parameter as not equal to zero and the hold parameter as equal to zero, with
WSEN = 0 (0 standard wait state), the SMC does not operate correctly.
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1768I–ATARM–09-Jul-09
Figure 18-45. Read-write Setup
MCK
A[22:0]
NRD
NWE
RWSETUP
Figure 18-46. Read Hold
MCK
A[22:0]
NRD
RWHOLD
Figure 18-47. Write Hold
MCK
A[22:0]
NWE
D[15:0]
RWHOLD
192
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19. SDRAM Controller (SDRAMC)
19.1
Overview
The SDRAM Controller (SDRAMC) extends the memory capabilities of a chip by providing
the interface to an external 16-bit or 32-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),
half-word (16-bit) and word (32-bit) accesses.
The SDRAM Controller supports a read or write burst length of one location. It does not
support byte Read/Write bursts or half-word write bursts. 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.
Features of the SDRAMC are:
• Numerous Configurations Supported
– 2K, 4K, 8K Row Address Memory Parts
– SDRAM with Two or Four Internal Banks
– SDRAM with 16- or 32-bit Data Path
• Programming Facilities
– Word, Half-word, 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
• Energy-saving Capabilities
– Self-refresh and Low-power Modes Supported
• Error Detection
– Refresh Error Interrupt
• SDRAM Power-up Initialization by Software
• Latency is Set to Two Clocks (CAS Latency of 1, 3 Not Supported)
• Auto Precharge Command Not Used
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19.2
Block Diagram
Figure 19-1. SDRAM Controller Block Diagram
PIO
Controller
SDRAMC
SDRAMC
Chip Select
SDCK
Memory
Controller
SDCKE
SDCS
SDRAMC
Interrupt
BA[1:0]
RAS
PMC
CAS
MCK
SDWE
NBS[3:0]
A[12:0]
D[31:0]
User Interface
APB
19.3
I/O Lines Description
Table 19-1.
I/O Line Description
Name
Description
Type
SDCK
SDRAM Clock
Output
SDCKE
SDRAM Clock Enable
Output
High
SDCS
SDRAM Controller Chip Select
Output
Low
BA[1:0]
Bank Select Signals
Output
RAS
Row Signal
Output
CAS
Column Signal
Output
Low
SDWE
SDRAM Write Enable
Output
Low
NBS[3:0]
Data Mask Enable Signals
Output
Low
A[12:0]
Address Bus
Output
D[31:0]
Data Bus
I/O
194
Active Level
Low
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AT91RM9200
19.4
Software Interface
The SDRAM Controller’s function is to make the SDRAM device access protocol transparent to
the user. Table 19-2 to Table 19-7 illustrate the SDRAM device memory mapping therefore seen
by the user in correlation with the device structure. Various configurations are illustrated.
19.4.1
32-bit Memory Data Bus Width
Table 19-2.
SDRAM Configuration Mapping: 2K Rows, 256/512/1024/2048 Columns
CPU Address Line
27
26
25
24
23
22
21
20
19
18
17
16
Bk[1:0]
Bk[1:0]
14
13
12
11
10
9
8
7
5
4
3
2
0
M[1:0]
Column[9:0]
Row[10:0]
1
M[1:0]
Column[8:0]
Row[10:0]
Bk[1:0]
6
Column[7:0]
Row[10:0]
Bk[1:0]
Table 19-3.
15
Row[10:0]
M[1:0]
Column[10:0]
M[1:0]
SDRAM Configuration Mapping: 4K Rows, 256/512/1024/2048 Columns
CPU Address Line
27
26
25
24
23
22
21
20
19
18
17
Bk[1:0]
15
14
13
12
11
10
9
8
7
Row[11:0]
Bk[1:0]
Bk[1:0]
6
5
4
3
2
Column[7:0]
Row[11:0]
0
M[1:0]
Column[9:0]
Row[11:0]
1
M[1:0]
Column[8:0]
Row[11:0]
Bk[1:0]
Table 19-4.
16
M[1:0]
Column[10:0]
M[1:0]
SDRAM Configuration Mapping: 8K Rows, 256/512/1024/2048 Columns
CPU Address Line
27
26
25
24
23
22
21
20
19
18
17
Bk[1:0]
Bk[1:0]
Notes:
15
Row[12:0]
Bk[1:0]
Bk[1:0]
16
Row[12:0]
Row[12:0]
Row[12:0]
14
13
12
11
10
9
8
7
6
5
Column[7:0]
Column[8:0]
Column[9:0]
Column[10:0]
4
3
2
1
0
M[1:0]
M[1:0]
M[1:0]
M[1:0]
1. M[1:0] is the byte address inside a 32-bit word.
2. Bk[1] = BA1, Bk[0] = BA0.
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1768I–ATARM–09-Jul-09
19.4.2
16-bit Memory Data Bus Width
Table 19-5.
SDRAM Configuration Mapping: 2K Rows, 256/512/1024/2048 Columns
CPU Address Line
27
26
25
24
23
22
21
20
19
18
17
16
15
Bk[1:0]
13
12
11
10
9
8
7
6
Row[10:0]
Bk[1:0]
4
3
2
1
M
0
M
0
Column[9:0]
Row[10:0]
0
M
0
Column[8:0]
Row[10:0]
Bk[1:0]
5
Column[7:0]
Row[10:0]
Bk[1:0]
Table 19-6.
14
M
0
Column[10:0]
SDRAM Configuration Mapping: 4K Rows, 256/512/1024/2048 Columns
CPU Address Line
27
26
25
24
23
22
21
20
19
18
17
16
Bk[1:0]
14
13
12
11
10
9
8
7
6
Row[11:0]
Bk[1:0]
4
3
2
1
M
0
M
0
Column[9:0]
Row[11:0]
0
M
0
Column[8:0]
Row[11:0]
Bk[1:0]
5
Column[7:0]
Row[11:0]
Bk[1:0]
Table 19-7.
15
M
0
Column[10:0]
SDRAM Configuration Mapping: 8K Rows, 256/512/1024/2048 Columns
CPU Address Line
27
26
25
24
23
22
21
20
19
18
17
16
Bk[1:0]
Bk[1:0]
Notes:
14
Row[12:0]
Bk[1:0]
Bk[1:0]
15
Row[12:0]
Row[12:0]
Row[12:0]
13
12
11
10
9
8
7
6
5
4
3
Column[7:0]
Column[8:0]
Column[9:0]
Column[10:0]
2
1
0
M
0
M
0
M
0
M
0
1. M0 is the byte address inside a 16-bit half-word.
2. Bk[1] = BA1, Bk[0] = BA0.
196
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19.5
Product Dependencies
19.5.1
SDRAM Device Initialization
The initialization sequence is generated by software. The SDRAM devices are initialized by the
following sequence:
1. A minimum pause of 200 µs is provided to precede any signal toggle.
2. An All Banks Precharge command is issued to the SDRAM devices.
3. Eight auto-refresh (CBR) cycles are provided.
4. A mode register set (MRS) cycle is issued to program the parameters of the SDRAM
devices, in particular CAS latency and burst length.
5. A Normal Mode command is provided, 3 clocks after tMRD is met.
6. Write refresh rate into the count field in the SDRAMC Refresh Timer register. (Refresh
rate = delay between refresh cycles).
After these six steps, the SDRAM devices are fully functional.
The commands (NOP, MRS, CBR, normal mode) are generated by programming the command
field in the SDRAMC Mode register
Figure 19-2. SDRAM Device Initialization Sequence
SDCKE
tRP
tRC
tMRD
SDCK
A[9:0]
A10
A[12:11]
SDCS
RAS
CAS
SDWE
NBS
Inputs Stable for
200 μsec
19.5.2
Precharge All Banks 1st Auto-refresh
8th Auto-refresh
MRS Command
Valid Command
I/O Lines
The pins used for interfacing the SDRAM Controller may be multiplexed with the PIO lines. The
programmer must first program the PIO controller to assign the SDRAM Controller pins to their
peripheral function. If I/O lines of the SDRAM Controller are not used by the application, they
can be used for other purposes by the PIO Controller.
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1768I–ATARM–09-Jul-09
19.5.3
Interrupt
The SDRAM Controller interrupt (Refresh Error notification) is connected to the Memory Controller. This interrupt may be ORed with other System Peripheral interrupt lines and is finally
provided as the System Interrupt Source (Source 1) to the AIC (Advanced Interrupt Controller).
Using the SDRAM Controller interrupt requires the AIC to be programmed first.
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19.6
Functional Description
19.6.1
SDRAM Controller Write Cycle
The SDRAM Controller allows burst access or single access. To initiate a burst access, the
SDRAM Controller 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 SDRAM Controller 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/active (t RP ) commands and
active/write (tRCD) commands. For definition of these timing parameters, refer to the Section
19.7.3 “SDRAMC Configuration Register” on page 208. This is described in Figure 19-3 below.
Figure 19-3. Write Burst, 32-bit SDRAM Access
tRCD = 3
SDCS
SDCK
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[31:0]
Dna
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1768I–ATARM–09-Jul-09
19.6.2
SDRAM Controller Read Cycle
The SDRAM Controller allows burst access or single access. To initiate a burst access, the
SDRAM Controller uses the transfer type signal provided by the master requesting the access. If
the next access is a sequential read access, reading to the SDRAM device is carried out. If the
next access is a sequential read access, but the current access is to a boundary page, or if the
next access is in another row, then the SDRAM Controller generates a precharge command,
activates the new row and initiates a read command. To comply with SDRAM timing parameters,
an additional clock cycle is inserted between the precharge/active (t RP ) command and the
active/read (tRCD) command, After a read command, additional wait states are generated to
comply with cas latency. The SDRAM Controller supports a cas latency of two. For definition of
these timing parameters, refer to 19.7.3 “SDRAMC Configuration Register” on page 208. This is
described in Figure 19-4 below.
Figure 19-4. Read Burst, 32-bit SDRAM access
tRCD = 3
CAS = 2
SDCS
SDCK
A[12:0]
Row n
col a
col b
col c
col d
col e
col f
RAS
CAS
SDWE
D[31:0]
(Input)
200
Dna
Dnb
Dnc
Dnd
Dne
Dnf
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19.6.3
Border Management
When the memory row boundary has been reached, an automatic page break is inserted. In this
case, the SDRAM controller 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/active (tRP) command and the active/read (tRCD) command. This is described in Figure 19-5 below.
Figure 19-5. Read Burst with Boundary Row Access
TRP = 3
TRCD = 3
CAS = 3
SDCS
SDCK
Row n
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[31:0]
Dna
Dnb
Dnc
Dnd
Dma
Dmb
Dmc
Dmd
Dme
201
1768I–ATARM–09-Jul-09
19.6.4
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 SDRAM Controller generates these auto-refresh commands periodically. A timer is loaded
with the value in the register SDRAMC_TR that indicates the number of clock cycles between
refresh cycles.
A refresh error interrupt is generated when the previous auto-refresh command did not perform.
It will be acknowledged by reading the Interrupt Status Register (SDRAMC_ISR).
When the SDRAM Controller initiates a refresh of the SDRAM device, internal memory accesses
are not delayed. However, if the CPU tries to access the SDRAM, the slave will indicate that the
device is busy and the ARM BWAIT signal will be asserted. See Figure 19-6 below.
Figure 19-6. Refresh Cycle Followed by a Read Access
tRP = 3
tRC = 8
tRCD = 3
CAS = 2
SDCS
SDCK
Row n
A[12:0]
col c
Row m
col d
col a
RAS
CAS
SDWE
D[31:0]
(input)
202
Dnb
Dnc
Dnd
Dma
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19.6.5
Power Management
19.6.5.1
Self-refresh Mode
Self-refresh mode is used in power-down mode, i.e., when no access to the SDRAM device is
possible. In this case, power consumption is very low. The mode is activated by programming
the self-refresh command bit (SRCB) in SDRAMC_SRR. 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 SDRAM
Controller provides a sequence of commands and exits self-refresh mode, so the self-refresh
command bit is disabled.
To re-activate this mode, the self-refresh command bit must be re-programmed.
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 19-7 below.
Figure 19-7. Self-refresh Mode Behavior
Self Refresh Mode
TXSR = 3
SRCB = 1
Write
SDRAMC_SRR
Row
A[12:0]
SDCK
SDCKE
SDCS
RAS
CAS
SDWE
Access Request
to the SDRAM Controller
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1768I–ATARM–09-Jul-09
19.6.5.2
Low-power Mode
Low-power mode is used in power-down mode, i.e., when no access to the SDRAM device is
possible. In this mode, power consumption is greater than in self-refresh mode. This state is similar to normal mode (No low-power mode/No self-refresh mode), but the SDCKE pin is low and
the input and output buffers are deactivated as soon as the SDRAM device is no longer accessible. 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 in this mode, the SDRAM Controller carries out the refresh operation.
In order to exit low-power mode, a NOP command is required. The exit procedure is faster than
in self-refresh mode.
When self-refresh mode is enabled, it is recommended to avoid enabling low-power mode.
When low-power mode is enabled, it is recommended to avoid enabling self-refresh mode.
This is described in Figure 19-8 below.
Figure 19-8. Low-power Mode Behavior
TRCD = 3
CAS = 2
Low Power Mode
SDCS
SDCK
A[12:0]
Row n
col a
col b
col c
col d
col e
col f
RAS
CAS
SDCKE
D[31:0]
(input)
204
Dna
Dnb
Dnc
Dnd
Dne
Dnf
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1768I–ATARM–09-Jul-09
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19.7
SDRAM Controller (SDRAMC) User Interface
Table 19-8.
Offset
SDRAM Controller Memory Map
Register
Name
Access
Reset State
0x00
SDRAMC Mode Register
SDRAMC_MR
Read/Write
0x00000010
0x04
SDRAMC Refresh Timer Register
SDRAMC_TR
Read/Write
0x00000800
0x08
SDRAMC Configuration Register
SDRAMC_CR
Read/Write
0x2A99C140
0x0C
SDRAMC Self Refresh Register
SDRAMC_SRR
Write-only
–
0x10
SDRAMC Low Power Register
SDRAMC_LPR
Read/Write
0x0
0x14
SDRAMC Interrupt Enable Register
SDRAMC_IER
Write-only
–
0x18
SDRAMC Interrupt Disable Register
SDRAMC_IDR
Write-only
–
0x1C
SDRAMC Interrupt Mask Register
SDRAMC_IMR
Read-only
0x0
0x20
SDRAMC Interrupt Status Register
SDRAMC_ISR
Read-only
0x0
205
1768I–ATARM–09-Jul-09
19.7.1
SDRAMC Mode Register
Register Name:
SDRAMC_MR
Access Type:
Read/Write
Reset Value:
0x00000010
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
DBW
3
2
1
0
MODE
• MODE: SDRAMC Command Mode
This field defines the command issued by the SDRAM Controller when the SDRAM device is accessed.
MODE
Description
0
0
0
0
Normal mode. Any access to the SDRAM is decoded normally.
0
0
0
1
The SDRAM Controller issues a NOP command when the SDRAM device is accessed regardless of the
cycle.
0
0
1
0
The SDRAM Controller issues an “All Banks Precharge” command when the SDRAM device is accessed
regardless of the cycle.
0
0
1
1
The SDRAM Controller issues a “Load Mode Register” command when the SDRAM device is accessed
regardless of the cycle. The address offset with respect to the SDRAM device base address is used to
program the Mode Register. For instance, when this mode is activated, an access to the “SDRAM_Base +
offset” address generates a “Load Mode Register” command with the value “offset” written to the SDRAM
device Mode Register.
0
1
0
0
The SDRAM Controller issues a “Refresh” Command when the SDRAM device is accessed regardless of
the cycle. Previously, an “All Banks Precharge” command must be issued.
• DBW: Data Bus Width
0: Data bus width is 32 bits.
1: Data bus width is 16 bits.
206
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19.7.2
SDRAMC Refresh Timer Register
Register Name:
SDRAMC_TR
Access Type:
Read/Write
Reset Value:
0x00000800
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
3
2
COUNT
• COUNT: SDRAMC 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 (MCK: Master Clock), the refresh rate
of the SDRAM device and the refresh burst length where 15.6 µs per row is a typical value for a burst of length one.
To refresh the SDRAM device even if the reset value is not equal to 0, 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.
207
1768I–ATARM–09-Jul-09
19.7.3
SDRAMC Configuration Register
Register Name:
SDRAMC_CR
Access Type:
Read/Write
Reset Value:
0x2A99C140
31
–
30
23
TRAS
22
15
TRP
14
7
TWR
6
29
28
27
26
25
TRAS
24
20
19
18
17
TRP
16
12
11
10
9
TWR
8
4
NB
3
2
1
TXSR
21
TRCD
13
TRC
5
CAS
NR
0
NC
• NC: Number of Column Bits
Reset value is 8 column bits.
NC
Column Bits
0
0
8
0
1
9
1
0
10
1
1
11
• NR: Number of Row Bits
Reset value is 11 row bits.
NR
Row Bits
0
0
11
0
1
12
1
0
13
1
1
Reserved
• NB: Number of Banks
Reset value is two banks.
NB
Number of Banks
0
2
1
4
• CAS: CAS Latency
Reset value is two cycles.
208
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In the SDRAMC, only a CAS latency of two cycles is managed. In any case, another value must be programmed.
CAS
CAS Latency (Cycles)
0
0
Reserved
0
1
Reserved
1
0
2
1
1
Reserved
• 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 2 and 15.
If TWR is less than or equal to 2, two clock periods are inserted by default.
• TRC: Row Cycle Delay
Reset value is eight cycles.
This field defines the delay between a Refresh and an Activate Command in number of cycles. Number of cycles is
between 2 and 15.
If TRC is less than or equal to 2, two clock periods are inserted by default.
• 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 2 and 15.
If TRP is less than or equal to 2, two clock periods are inserted by default.
• TRCD: Row to Column Delay
Reset value is three cycles.
This field defines the delay between an Activate Command and a Read/Write Command in number of cycles. Number of
cycles is between 2 and 15.
If TRCD is less than or equal to 2, two clock periods are inserted by default.
• 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 2 and 15.
If TRAS is less than or equal to 2, two clock periods are inserted by default.
• TXSR: Exit Self Refresh to Active Delay
Reset value is five cycles.
This field defines the delay between SCKE set high and an Activate Command in number of cycles. Number of cycles is
between 1/2 and 15.5.
If TXSR is equal to 0, 1/2 clock period is inserted by default.
209
1768I–ATARM–09-Jul-09
19.7.4
SDRAMC Self-refresh Register
Register Name:
SDRAMC_SRR
Access Type:
Write-only
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
SRCB
• SRCB: Self-refresh Command Bit
0: No effect.
1: The SDRAM Controller issues a self-refresh command to the SDRAM device, the SDCK clock is inactivated and the
SDCKE signal is set low. The SDRAM device leaves self-refresh mode when accessed again.
19.7.5
SDRAMC Low-power Register
Register Name:
SDRAMC_LPR
Access Type:
Read/Write
Reset Value:
0x0
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
LPCB
• LPCB: Low-power Command Bit
0: The SDRAM Controller low-power feature is inhibited: no low-power command is issued to the SDRAM device.
1: The SDRAM Controller issues a low-power command to the SDRAM device after each burst access, the SDCKE signal
is set low. The SDRAM device will leave low-power mode when accessed and enter it after the access.
210
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
19.7.6
SDRAMC Interrupt Enable Register
Register Name:
SDRAMC_IER
Access Type:
Write-only
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
0: No effect.
1: Enables the refresh error interrupt.
19.7.7
SDRAMC Interrupt Disable Register
Register Name:
SDRAMC_IDR
Access Type:
Write-only
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
0: No effect.
1: Disables the refresh error interrupt.
211
1768I–ATARM–09-Jul-09
19.7.8
SDRAMC Interrupt Mask Register
Register Name:
SDRAMC_IMR
Access Type:
Read-only
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
0: The refresh error interrupt is disabled.
1: The refresh error interrupt is enabled.
212
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
19.7.9
SDRAMC Interrupt Status Register
Register Name:
SDRAMC_ISR
Access Type:
Read-only
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
0: No refresh error has been detected since the register was last read.
1: A refresh error has been detected since the register was last read.
213
1768I–ATARM–09-Jul-09
214
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
20. Burst Flash Controller (BFC)
20.1
Overview
The Burst Flash Controller (BFC) provides an interface for external 16-bit Burst Flash devices
and handles an address space of 256M bytes. It supports byte, half-word and word aligned
accesses and can access up to 32M bytes of Burst Flash devices. The BFC also supports data
bus and address bus multiplexing. The Burst Flash interface supports only continuous burst
reads. Programmable burst lengths of four or eight words are not possible. The BFC never generates an abort signal, regardless of the requested address within the 256M bytes of address
space.
The BFC can operate with two burst read protocols depending on whether or not the address
increment of the Burst Flash device is signal controlled. The Burst Flash Controller Mode Register (BFC_MR) located in the BFC user interface is used in programming Asynchronous or Burst
Operating Modes. In Burst Mode, the read protocol, Clock Controlled Address Advance, automatically increments the address at each clock cycle. Whereas in Signal Controlled Address
Advance protocol the address is incremented only when the Burst Address Advance signal is
active. When Address and Data Bus Multiplexing Mode is chosen, the sixteen lowest address
bits are multiplexed with the data bus.
The BFC clock speed is programmable to be either master clock or master clock divided by 2 or
4. Page size handling (16 bytes to 1024 bytes) is required by some Burst Flash devices unable
to handle continuous burst read. The number of latency cycles after address valid goes up to
sixteen cycles. The number of latency cycles after output enable runs between one and three
cycles. The Burst Flash Controller can also be programmed to suspend and maintain the current
burst. This attribute gives other devices the possibility to share the BFC busses without any loss
of efficiency. In Burst Mode, the BFC can restart a sequential access without any additional
latency.
Features of the Burst Flash Controller are:
• Multiple Access Modes Supported
– Asynchronous or Burst Mode Byte, Half-word or Word Read Accesses
– Asynchronous Mode Half-word Write Accesses
• Adaptability to Different Device Speed Grades
– Programmable Burst Flash Clock Rate
– Programmable Data Access Time
– Programmable Latency after Output Enable
• Adaptability to Different Device Access Protocols and Bus Interfaces
– Two Burst Read Protocols: Clock Control Address Advance or Signal Controlled
Address Advance
– Multiplexed or Separate Address and Data Busses
– Continuous Burst and Page Mode Accesses Supported
215
1768I–ATARM–09-Jul-09
20.2
Block Diagram
Figure 20-1. Burst Flash Controller Block Diagram
PIO
Controller
BFC
Memory
Controller
BFC
Chip Select
BFCK
BFCS
BFAVD
BFBAA
BFOE
PMC
BFWE
MCK
BFRDY
A[24:0]
D[15:0]
User Interface
APB
20.3
I/O Lines Description
Table 20-1.
I/O Lines Description
Name
Description
Type
BFCK
Burst Flash Clock
Output
BFCS
Burst Flash Chip Select
Output
Low
BFAVD
Burst Flash Address Valid
Output
Low
BFBAA
Burst Flash Address Advance
Output
Low
BFOE
Burst Flash Output Enable
Output
Low
BFWE
Burst Flash Write Enable
Output
Low
BFRDY
Burst Flash Ready
Input
High
A[24:0]
Address Bus
Output
D[15:0]
Data Bus
I/O
216
Active Level
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
20.4
20.4.1
Application Example
Burst Flash Interface
The Burst Flash Interface provides control, address and data signals to the Burst Flash Memory.
These signals are detailed in Section 20.6 “Functional Description” on page 218 which describes
the BFC functionality and operating modes. Figure 20-2 below presents an illustration of the
possible connections of the BFC to some popular Burst Flash Memories.
Figure 20-2. Burst Flash Controller Connection Example
Burst Flash
BFC
BFC
[D0:D15]
[A0:A22]
BFCK
BFAVD
Burst Flash
[D0:D15]
[D0:D15]
[A0:A22]
[A16:A21]
clk
avd/adv
BFCK
BFAVD
[AD0:AD15]
[A16:A21]
clk
avd
BFCS
ce
BFCS
ce
BFOE
oe
BFOE
oe
BFWE
we
rdy/wait
BFWE
we
BFRDY
rdy
BFRDY
Clock Controlled Address Advance
Clock Controlled Address Advance
Multiplexed Bus Disabled
Multiplexed Bus Enabled
Burst Flash
Burst Flash
BFC
BFC
[D0:D15]
[D0:D15]
[D0:D15]
[A0:A19]
[A0:A19]
[A16:A19]
[AD0:AD15]
[A16:A19]
BFCK
clk
BFCK
clk
BFCS
ce
BFCS
ce
BFAVD
avd/lba
BFAVD
avd
BFBAA
baa
BFBAA
baa
BFOE
oe
BFOE
oe
BFWE
we
BFWE
we
BFRDY
rdy
BFRDY
rdy/ind
Signal Controlled Address Advance
Signal Controlled Address Advance
Multiplexed Bus Disabled
Multiplexed Bus Enabled
217
1768I–ATARM–09-Jul-09
20.5
20.5.1
Product Dependencies
I/O Lines
The pins used for interfacing the Burst Flash Controller may be multiplexed with the PIO lines.
The programmer must first program the PIO controller to assign the Burst Flash Controller pins
to their peripheral function. If I/O lines of the Burst Flash Controller are not used by the application, they can be used for other purposes by the PIO Controller.
20.6
Functional Description
The Burst Flash Controller drives the following signals:
• Address Valid (BFAVD), to latch the addresses
• Clock (BFCK), to supply the burst clock
• Burst Advance Address (BFBAA), to control the Burst Flash memory address advance when
programmed to operate in signal controlled burst advance
• Write Enable (BFWE), to write to the Burst Flash device
• Output Enable (BFOE), to enable the external device data drive on the data bus
When enabled, the BFC also drives the address bus, the data bus and the Chip Select (BFCS)
line. The Ready Signal (BFRDY) is taken as an input and used as an indicator for the next data
availability.
20.6.1
Burst Flash Controller Reset State
After reset, the BFC is disabled and, therefore, must be enabled by programming the field
BFCOM. See “Burst Flash Controller Mode Register” on page 227. At this time, the Burst Flash
Controller operates in Asynchronous Mode. The Burst Flash memory can be programmed by
writing and reading in Asynchronous Mode.
20.6.2
Burst Flash Controller Clock Selection
The BFC clock rate is programmable to be either Master Clock, Master Clock divided by 2 or
Master Clock divided by 4. The clock selection is necessary in Burst Mode as well as in Asynchronous Mode. The latency fields in the mode register and all burst Flash control signal
waveforms are related to the Burst Flash Clock (BFCK) period.
The BFC clock rate is selected by the BFCC field. “Burst Flash Controller Mode Register” on
page 227
Figure 20-3. Burst Flash Clock Rates
MCK
MCK
MCK
BFC Clock
BFC Clock
BFC Clock
BFCC = 1
20.6.3
BFCC = 2
BFCC = 3
Burst Flash Controller Asynchronous Mode
In Asynchronous Mode, the Burst Flash Controller clock is off. The BFCK signal is driven low.
The BFC performs read access to bytes (8-bits), half-words (16-bits), and words (32-bits). In the
last case, the BFC autonomously transforms the word read request into two separate half-word
reads. This is fully transparent to the user.
218
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
The BFC performs only half-word write requests. Write requests for bytes or words are ignored
by the BFC.
For any access in the address space, the address is driven on the address bus while a pulse is
driven on the BFAVD signal (see Figure 20-4 on page 220, and Figure 20-5 on page 221). The
Burst Flash address is also driven on the data bus if the multiplexed data and address bus
options are enabled. (Figure 20-4 on page 220).
• For write access, the signal BFWE is asserted in the following BFCK clock cycle.
• For read access, the signal BFOE is asserted one cycle later. This additional cycle in read
accesses has been inserted to switch the I/O pad direction so as to avoid conflict on the Burst
Flash data bus when address and data busses are multiplexed.
The Address Valid Latency (AVL) determines the length of the pulses as a number of Master
Clock cycles. The AVL field See “Burst Flash Controller Mode Register” on page 227. is coded
as the Address Valid Latency minus 1. Waveforms in Figure 20-4 on page 220 and Figure 20-5
on page 221 show the AVL field definition in read and write accesses.
• In read access, the access finishes with the rising edge of BFOE.
• In write access, data and address lines are released one half cycle after the rising edge of
BFWE.
After a read access to the Burst Flash, it takes Output Enable Latency (OEL) cycles for the Burst
Flash device to release the data bus. The OEL field See “Burst Flash Controller Mode Register”
on page 227. gives the OEL expressed in BFCK Clock cycles. This prevents other memory controllers from using the Data Bus until it is released by the Burst Flash device.
In Figure 20-4 on page 220 (multiplexed address and data busses), one idle cycle (OEL = 1) is
inserted between the read and write accesses. The Burst Flash device must release the data
bus before the BFC can drive the address. As shown in Figure 20-5 on page 221, where busses
are not multiplexed, the write access can start as soon as the read access ends. In the same
way, the OEL has no impact when a read follows a write access.
Waveforms in Figure 20-4 on page 220 below and Figure 20-5 on page 221 are related to the
Burst Flash Controller Clock even though the BFCK pin is driven low in Asynchronous Mode.
The BFCC field See “Burst Flash Controller Mode Register” on page 227.is used as a measure
of the burst Flash speed and must also be programmed in Asynchronous Mode.
219
1768I–ATARM–09-Jul-09
Figure 20-4. Asynchronous Read and Write Accesses with Multiplexed Address and Data Buses
BFCS
BFCK
A[24:0]
Read Address
Write Address
BFAVD
AVL
BFOE
AVL
BFWE
D[15:0]
Output
Write Address
Read Address
D[15:0]
Input
Data
Data
OEL = 1
Asynchronous
Read Access
Asynchronous
Write Access
Address Valid Latency = 4 BFCK cycles (AVL field = 3)
Output Enable Latency (OEL) = 1 BFCK cycle
220
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Figure 20-5. Asynchronous Read and Write Accesses with Non-multiplexed Address and Data
BFCS
BFCK
A[24:0]
Write Address
Read Address
BFAVD
AVL
BFOE
AVL
BFWE
D[15:0]
Output
Data
D[15:0]
Input
Data
OEL = 1
Asynchronous
Read Access
Asynchronous
Write Access
Address Valid Latency = 4 BFCK cycles (AVL field = 3)
Output Enable Latency (OEL) = 1 BFCK cycle
20.6.4
20.6.4.1
Burst Flash Controller Synchronous Mode
Writing the Burst Flash Controller Operating Mode field (BFCOM) to 2 See “Burst Flash Controller Mode Register” on page 227. puts the BFC in Burst Mode. The BFC Clock is driven on the
BFCK pin. Only read accesses are treated and write accesses are ignored. The BFC supports
read access of bytes, half-words or words.
Burst Read Protocols
The BFC supports two burst read protocols:
• Clock Controlled Address Advance, the internal address of the burst Flash is automatically
incremented at each BFCK cycle.
• Signal Controlled Address Advance, the internal address of the burst Flash is incremented
only when the BFBAA signal is active.
20.6.4.2
Read Access in Burst Mode
When a read access is requested in Burst Mode, the requested address is registered in the
BFC. For subsequent read accesses, the address is compared to the previous one. Then the
two following cases are considered:
1. In case of a non-sequential access, the current burst is broken and the BFC launches a
new burst by performing an address latch cycle. The address is presented on the
address bus in any case and on the data bus if the multiplexed bus option is enabled.
221
1768I–ATARM–09-Jul-09
This new address is registered in the BFC and is then used as reference for further
accesses.
2. In case of sequential access, and provided that the BFOEH mode is selected in the
mode register See “Burst Flash Controller Mode Register” on page 227., the internal
burst address is incremented:
– Through the BFBAA pin, if the Signal Controlled Address Advance is enabled.
– By enabling the clock during one clock cycle in Clock Controlled Address Advance
Mode.
These protocols are illustrated in Figure 20-6 below and Figure 20-7 on page 223. The Address
Valid Latency AVL+1 See “Burst Flash Controller Mode Register” on page 227. gives the number of cycles from the first rising clock edge when BFAVD is asserted to the rising edge that
causes the read of data D1.
Note:
This rising edge is also used to latch D0 in the BFC.
Figure 20-6. Burst Suspend and Resume with Signal Control Address Advance
BFCS
Internal BFC
Selection Signal
BFCK
A[24:0]
Address (D0)
BFAVD
OEL = 2
AVL
BFOE
BFWE
Burst Suspend
Burst Resume
BFBAA
D[15:0]
Output
Address (1)
D[15:0]
Input
D0
D1
D0
Sampling
D2
222
D4
D4
D5
D6
D5
Sampling
D2
Sampling
D1
Sampling
Burst Suspend and Resume (BFOEH = 1)
Signal Control Address Advance (BAAEN = 1)
(1) Only if Multiplexed Address & Data Buses
D3
D3
Sampling
D4
Sampling
Address Valid Latency = 4 BFCK cycles (AVL field = 3)
Output Enable Latency (OEL) = 2 BFCK cycles
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Figure 20-7. Burst Suspend and Resume with Clock Control Address Advance
Burst Suspend
BFCS
Burst Resume
Internal BFC
Selection Signal
BFCK
Address (D0)
A[24:0]
BFAVD
OEL = 2
AVL
BFOE
BFWE
D[15:0]
Output
Address (1)
D[15:0]
Input
D0
D1
D0
Sampling
D2
20.6.4.3
D4
D2
Sampling
D1
Sampling
Burst Suspend and Resume (BFOEH = 1)
Clock Control Address Advance (BAAEN = 0)
(1) Only if Multiplexed Address & Data Buses
D3
D3
Sampling
D4
D5
D6
D5
Sampling
D4
Sampling
Address Valid Latency = 4 BFCK cycles (AVL = 3)
Output Enable Latency (OEL) = 2 BFCK cycles
Burst Suspension for Transfer Enabling
The BFC can suspend a burst to enable other internal transfers, or other memory controllers to
use the memory address and data busses if they are shared. Two modes are provided on the
BFOEH bit (Burst Flash Output Enable Handling, See “Burst Flash Controller Mode Register” on
page 227.):
• BFOEH = 1: the BFC suspends the burst when it is no longer selected and the BFOE pin is
deasserted. When a new sequential access on the Burst Flash device is requested, the burst
is resumed and the BFOE pin is asserted again. The data is available on the data bus after
OEL cycles. This mode provides a minimal access latency. (Refer to Figure 20-6 on page 222
and Figure 20-7 above).
• BFOEH = 0: the BFC suspends the burst when it is no longer selected and the BFOE pin is
deasserted. When a new access to the Burst Flash device is requested, either sequential or
not, a new burst is initialized and the next data is available as defined by the AVL latency field
in the Mode Register. This mode is provided for Burst Flash devices for which the deassertion
of the BFOE signal causes an irreversible break of the burst. Figure 20-8 on page 224 shows
the access request to the BFC and the deassertion of the BFOE signal due to a deselection
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1768I–ATARM–09-Jul-09
of the BFC (Suspend). When the BFC is requested again, a new burst is started even though
the requested address is sequential to the previously requested address.
Figure 20-8. Burst Flash Controller with No Burst Enable Handling
Internal
Clock (2)
Internal
Address Bus
A0
A1
A2
Burst Suspend
A3
Begin New Burst
Internal BFC
Selection Signal
BFCS
BFCK
Address (D0)
A[24:0]
Address (D2)
BFAVD
OEL = 1
AVL
AVL
BFOE
BFWE
D[15:0]
Output
Address (1)
Address (1)
D[15:0]
Input
D0
D1
D2
D2
D3
D4
BFBAA
D0
Sampling
D1
Sampling
(1) Only if Multiplexed Address & Data Busses
(2) Master Clock Mode (BFCC =1)
20.6.4.4
D3
Sampling
Address Valid Latency = 4 BFCK cycles
Output Enable Latency (OEL) = 1 BFCK cycle
D2
Sampling
No Burst Output Enable Handling (BFOEH = 0)
Signal Control Advance Address (BAAEN = 1)
Continuous Burst Reads
The BFC performs continuous burst reads. It is also possible to program page sizes from 16
bytes up to 1024 bytes. This is done by setting the appropriate value in the PAGES field of the
“Burst Flash Controller Mode Register” on page 227.
Page Mode
224
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In Page Mode, the BFC stops the current burst and starts a new burst each time the requested
address matches a page boundary. Figure 20-9 on page 225 illustrates a 16-byte page size.
Data D0 to D10 belong to two separate pages and are accessed through two burst accesses.
This mode is provided for Burst Flash devices that cannot handle continuous burst read (in
which case, a continuous burst access to address D0 would cause the Burst Flash internal
address to wrap around address D0). Page Mode can be disabled by programming a null value
in the PAGES field of the “Burst Flash Controller Mode Register” on page 227.
Figure 20-9. Burst Read in Page Mode
16-byte Page Boundary
(1)
BFCS
BFCK
…..
A[24:0]
Address (D0)
Address (D8)
BFAVD
AVL
AVL
(1)
BFOE
BFWE
D[15:0]
Output
D[15:0]
Input
D0
D1
…..
D6
D7
D0
D8
D9
D10
BFBAA
D0
Sampling
D7
Sampling
D8 (1)
Sampling
16-byte Page
16-byte Page
(8 Accesses of 2 Bytes Each)
(8 Accesses of 2 Bytes Each)
Burst Read in Page Mode (16 Bytes)
Signal Control Advance Address (BAAEN = 1)
(1) A New Page Begins at D8
Address Valid Latency = 3 BFCK cycles (AVL field = 2)
Output Enable Latency (OEL) = 1 BFCK cycle
Page Size = 16 Bytes
Ready Enable Mode
In Ready Enable Mode (bit RDYEN in the “Burst Flash Controller Mode Register” on page 227),
the BFC uses the Ready Signal (BFRDY) from the burst Flash device as an indicator of the next
data availability. The BFRDY signal must be asserted one BFCK cycle before data is valid. In
Figure 20-10 on page 226 below, the BFRDY signal indicates on edge (A) that the expected D4
data will not be available on the next rising BFCK edge. The BFRDY signal remains low until rising at edge (B). D4 is then sampled on edge (C).
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1768I–ATARM–09-Jul-09
When the RDYEN mode is disabled (RDYEN = 0), the BFRDY signal at the BFC input interface
is ignored. This mode is provided for Burst Flash devices that do not handle the BFRDY signal.
Figure 20-10. Burst Read Using BFRDY Signal
(A)
(B)
(C)
BFCS
BFCK
Address (D0)
A[24:0]
BFAVD
AVL
BFOE
D[15:0]
Input
D0
D1
D2
D0
D1
D2
D3
D4
D5
D6
D7
D4
D5
D6
D7
BFBAA
BFRDY
Sampling
Burst Read
Signal Control Advance Address (BAAEN = 1)
226
D3
Address Valid Latency = 4 BFCK cycles (AVL field = 3)
Output Enable Latency (OEL) = 1 BFCK cycle
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20.7
Burst Flash Controller (BFC) User Interface
20.7.1
Burst Flash Controller Mode Register
Register Name:
BFC_MR
Access Type:
Read/Write
Reset Value
:0x0
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
RDYEN
18
MUXEN
17
BFOEH
16
BAAEN
15
–
14
–
13
12
11
10
9
PAGES
8
7
6
5
4
3
2
1
0
OEL
AVL
BFCC
BFCOM
• BFCOM: Burst Flash Controller Operating Mode
BFCOM
BFC Operating Mode
0
0
Disabled.
0
1
Asynchronous
1
0
Burst Read
1
1
Reserved
• BFCC: Burst Flash Controller Clock
BFCC
BFC Clock
0
0
Reserved
0
1
Master Clock
1
0
Master Clock divided by 2
1
1
Master Clock divided by 4
• AVL: Address Valid Latency
The Address Valid Latency is defined as the number of BFC Clock Cycles from the first BFCK rising edge when BFAVD is
asserted to the BFCK rising edge that samples read data. The Latency is equal to AVL + 1.
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1768I–ATARM–09-Jul-09
• PAGES: Page Size
This field defines the page size handling and the page size.
Pages
Page Size
0
0
0
No page handling. The Ready Signal (BFRDY) is sampled to check if the next
data is available.
0
0
1
16 bytes page size
0
1
0
32 bytes page size
0
1
1
64 bytes page size
1
0
0
128 bytes page size
1
0
1
256 bytes page size
1
1
0
512 bytes page size
1
1
1
1024 bytes page size
• OEL: Output Enable Latency
This field defines the number of idle cycles inserted after each level change on the BFOE output enable signal. OEL range
is 1 to 3.
• BAAEN: Burst Address Advance Enable
0: The burst clock is enabled to increment the burst address or, disabled to remain at the same address.
1: The burst clock is continuous and the burst address advance is controlled with the BFBAA pin.
• BFOEH: Burst Flash Output Enable Handling
0: No burst resume in Burst Mode. When the BFC is deselected, this causes an irreversible break of the burst. A new burst
will be initiated for the next access.
1: Burst resume. When the BFC is deselected, the burst is suspended. It will be resumed if the next access is sequential to
the last one.
• MUXEN: Multiplexed Bus Enable
0: The address and data busses operate independently.
1: The address and data busses are multiplexed. Actually, the address is presented on both the data bus and the address
bus when the BFAVD signal is asserted.
• RDYEN: Ready Enable Mode
0: The BFRDY input signal at the BFC input interface is ignored.
1: The BFRDY input signal is used as an indicator of data availability in the next cycle.
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21. Peripheral DMA Controller (PDC)
21.1
Overview
The Peripheral DMA Controller (PDC) transfers data between on-chip serial peripherals such as
the UART, USART, SSC, SPI, MCI and the on- and off-chip memories. Using the Peripheral
DMA Controller avoids processor intervention and removes the processor interrupt-handling
overhead.This significantly reduces the number of clock cycles required for a data transfer and,
as a result, improves the performance of the microcontroller and makes it more power efficient.
The PDC channels are implemented in pairs, each pair being dedicated to a particular peripheral. One channel in the pair is dedicated to the receiving channel and one to the transmitting
channel of each UART, USART, SSC and SPI.
The user interface of a PDC channel is integrated in the memory space of each peripheral. It
contains:
• A 32-bit memory pointer register
• A 16-bit transfer count register
• A 32-bit register for next memory pointer
• A 16-bit register for next transfer count
The peripheral triggers PDC transfers using transmit and receive signals. When the programmed data is transferred, an end of transfer interrupt is generated by the corresponding
peripheral.
Important features of the PDC are:
• Generates Transfers to/from Peripherals Such as DBGU, USART, SSC, SPI and MCI
• Supports Up to Twenty Channels (Product Dependent)
• One Master Clock Cycle Needed for a Transfer from Memory to Peripheral
• Two Master Clock Cycles Needed for a Transfer from Peripheral to Memory
21.2
Block Diagram
Figure 21-1. Block Diagram
Peripheral
Peripheral DMA Controller
THR
PDC Channel 0
RHR
PDC Channel 1
Control
Control
Memory
Controller
Status & Control
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21.3
21.3.1
Functional Description
Configuration
The PDC channels user interface enables the user to configure and control the data transfers for
each channel. The user interface of a PDC channel is integrated into the user interface of the
peripheral (offset 0x100), which it is related to.
Per peripheral, it contains four 32-bit Pointer Registers (RPR, RNPR, TPR, and TNPR) and four
16-bit Counter Registers (RCR, RNCR, TCR, and TNCR).
The size of the buffer (number of transfers) is configured in an internal 16-bit transfer counter
register, and it is possible, at any moment, to read the number of transfers left for each channel.
The memory base address is configured in a 32-bit memory pointer by defining the location of
the first address to access in the memory. It is possible, at any moment, to read the location in
memory of the next transfer and the number of remaining transfers. The PDC has dedicated status registers which indicate if the transfer is enabled or disabled for each channel. The status for
each channel is located in the peripheral status register. Transfers can be enabled and/or disabled by setting TXTEN/TXTDIS and RXTEN/RXTDIS in PDC Transfer Control Register. These
control bits enable reading the pointer and counter registers safely without any risk of their
changing between both reads.
The PDC sends status flags to the peripheral visible in its status-register (ENDRX, ENDTX,
RXBUFF, and TXBUFE).
ENDRX flag is set when the PERIPH_RCR register reaches zero.
RXBUFF flag is set when both PERIPH_RCR and PERIPH_RNCR reach zero.
ENDTX flag is set when the PERIPH_TCR register reaches zero.
TXBUFE flag is set when both PERIPH_TCR and PERIPH_TNCR reach zero.
These status flags are described in the peripheral status register.
21.3.2
Memory Pointers
Each peripheral is connected to the PDC by a receiver data channel and a transmitter data
channel. Each channel has an internal 32-bit memory pointer. Each memory pointer points to a
location anywhere in the memory space (on-chip memory or external bus interface memory).
Depending on the type of transfer (byte, half-word or word), the memory pointer is incremented
by 1, 2 or 4, respectively for peripheral transfers.
If a memory pointer is reprogrammed while the PDC is in operation, the transfer address is
changed, and the PDC performs transfers using the new address.
21.3.3
Transfer Counters
There is one internal 16-bit transfer counter for each channel used to count the size of the block
already transferred by its associated channel. These counters are decremented after each data
transfer. When the counter reaches zero, the transfer is complete and the PDC stops transferring data.
If the Next Counter Register is equal to zero, the PDC disables the trigger while activating the
related peripheral end flag.
If the counter is reprogrammed while the PDC is operating, the number of transfers is updated
and the PDC counts transfers from the new value.
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Programming the Next Counter/Pointer registers chains the buffers. The counters are decremented after each data transfer as stated above, but when the transfer counter reaches zero,
the values of the Next Counter/Pointer are loaded into the Counter/Pointer registers in order to
re-enable the triggers.
For each channel, two status bits indicate the end of the current buffer (ENDRX, ENTX) and the
end of both current and next buffer (RXBUFF, TXBUFE). These bits are directly mapped to the
peripheral status register and can trigger an interrupt request to the AIC.
The peripheral end flag is automatically cleared when one of the counter-registers (Counter or
Next Counter Register) is written.
Note: When the Next Counter Register is loaded into the Counter Register, it is set to zero.
21.3.4
Data Transfers
The peripheral triggers PDC transfers using transmit (TXRDY) and receive (RXRDY) signals.
When the peripheral receives an external character, it sends a Receive Ready signal to the PDC
which then requests access to the system bus. When access is granted, the PDC starts a read
of the peripheral Receive Holding Register (RHR) and then triggers a write in the memory.
After each transfer, the relevant PDC memory pointer is incremented and the number of transfers left is decremented. When the memory block size is reached, a signal is sent to the
peripheral and the transfer stops.
The same procedure is followed, in reverse, for transmit transfers.
21.3.5
Priority of PDC Transfer Requests
The Peripheral DMA Controller handles prioritized transfer requests from the channel.
If simultaneous requests of the same type (receiver or transmitter) occur on identical peripherals, the priority is determined by the numbering of the peripherals.
If transfer requests are not simultaneous, they are treated in the order they occurred. Requests
from the receivers are handled first and then followed by transmitter requests.
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1768I–ATARM–09-Jul-09
21.4
Peripheral DMA Controller (PDC) User Interface
Table 21-1.
Offset
Peripheral DMA Controller (PDC) Register Mapping
Register
Register Name
(1)
Read/Write
Reset
0x100
PDC Receive Pointer Register
PERIPH _RPR
Read/Write
0x0
0x104
PDC Receive Counter Register
PERIPH_RCR
Read/Write
0x0
0x108
PDC Transmit Pointer Register
PERIPH_TPR
Read/Write
0x0
0x10C
PDC Transmit Counter Register
PERIPH_TCR
Read/Write
0x0
0x110
PDC Receive Next Pointer Register
PERIPH_RNPR
Read/Write
0x0
0x114
PDC Receive Next Counter Register
PERIPH_RNCR
Read/Write
0x0
0x118
PDC Transmit Next Pointer Register
PERIPH_TNPR
Read/Write
0x0
0x11C
PDC Transmit Next Counter Register
PERIPH_TNCR
Read/Write
0x0
0x120
PDC Transfer Control Register
PERIPH_PTCR
Write-only
-
0x124
PDC Transfer Status Register
PERIPH_PTSR
Read-only
0x0
Note:
232
1. PERIPH: Ten registers are mapped in the peripheral memory space at the same offset. These can be defined by the user
according to the function and the peripheral desired (DBGU, USART, SSC, SPI, MCI etc).
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21.4.1
PDC Receive Pointer Register
Register Name:
PERIPH_RPR
Access Type:
31
Read/Write
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
RXPTR
23
22
21
20
RXPTR
15
14
13
12
RXPTR
7
6
5
4
RXPTR
• RXPTR: Receive Pointer Address
Address of the next receive transfer.
21.4.2
PDC Receive Counter Register
Register Name:
PERIPH_RCR
Access Type:
31
Read/Write
30
29
28
-23
22
21
20
-15
14
13
12
RXCTR
7
6
5
4
RXCTR
• RXCTR: Receive Counter Value
Number of receive transfers to be performed.
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21.4.3
PDC Transmit Pointer Register
Register Name:
PERIPH_TPR
Access Type:
31
Read/Write
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
TXPTR
23
22
21
20
TXPTR
15
14
13
12
TXPTR
7
6
5
4
TXPTR
• TXPTR: Transmit Pointer Address
Address of the transmit buffer.
21.4.4
PDC Transmit Counter Register
Register Name:
PERIPH_TCR
Access Type:
31
Read/Write
30
29
28
-23
22
21
20
-15
14
13
12
TXCTR
7
6
5
4
TXCTR
• TXCTR: Transmit Counter Value
·TXCTR is the size of the transmit transfer to be performed. At zero, the peripheral DMA transfer is stopped.
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21.4.5
PDC Receive Next Pointer Register
Register Name:
PERIPH_RNPR
Access Type:
31
Read/Write
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
RXNPTR
23
22
21
20
RXNPTR
15
14
13
12
RXNPTR
7
6
5
4
RXNPTR
• RXNPTR: Receive Next Pointer Address
RXNPTR is the address of the next buffer to fill with received data when the current buffer is full.
21.4.6
PDC Receive Next Counter Register
Register Name:
PERIPH_RNCR
Access Type:
31
Read/Write
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
RXNCR
7
6
5
4
RXNCR
• RXNCR: Receive Next Counter Value
·RXNCR is the size of the next buffer to receive.
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21.4.7
PDC Transmit Next Pointer Register
Register Name:
PERIPH_TNPR
Access Type:
31
Read/Write
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
TXNPTR
23
22
21
20
TXNPTR
15
14
13
12
TXNPTR
7
6
5
4
TXNPTR
• TXNPTR: Transmit Next Pointer Address
TXNPTR is the address of the next buffer to transmit when the current buffer is empty.
21.4.8
PDC Transmit Next Counter Register
Register Name:
PERIPH_TNCR
Access Type:
31
Read/Write
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
TXNCR
7
6
5
4
TXNCR
• TXNCR: Transmit Next Counter Value
TXNCR is the size of the next buffer to transmit.
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21.4.9
PDC Transfer Control Register
Register Name:
PERIPH_PTCR
Access Type:
Write-only
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
–
–
–
TXTDIS
TXTEN
7
6
5
4
3
2
1
0
–
–
–
–
–
–
RXTDIS
RXTEN
• RXTEN: Receiver Transfer Enable
0 = No effect.
1 = Enables the receiver PDC transfer requests if RXTDIS is not set.
• RXTDIS: Receiver Transfer Disable
0 = No effect.
1 = Disables the receiver PDC transfer requests.
• TXTEN: Transmitter Transfer Enable
0 = No effect.
1 = Enables the transmitter PDC transfer requests.
• TXTDIS: Transmitter Transfer Disable
0 = No effect.
1 = Disables the transmitter PDC transfer requests
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21.4.10 PDC Transfer Status Register
Register Name:
PERIPH_PTSR
Access Type:
Read-only
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
–
–
–
–
TXTEN
7
6
5
4
3
2
1
0
–
–
–
–
–
–
–
RXTEN
• RXTEN: Receiver Transfer Enable
0 = Receiver PDC transfer requests are disabled.
1 = Receiver PDC transfer requests are enabled.
• TXTEN: Transmitter Transfer Enable
0 = Transmitter PDC transfer requests are disabled.
1 = Transmitter PDC transfer requests are enabled.
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22. Advanced Interrupt Controller (AIC)
22.1
Overview
The Advanced Interrupt Controller (AIC) is an 8-level priority, individually maskable, vectored
interrupt controller, providing handling of up to thirty-two interrupt sources. It is designed to substantially reduce the software and real-time overhead in handling internal and external
interrupts.
The AIC drives the nFIQ (fast interrupt request) and the nIRQ (standard interrupt request) inputs
of an ARM processor. Inputs of the AIC are either internal peripheral interrupts or external interrupts coming from the product's pins.
The 8-level Priority Controller allows the user to define the priority for each interrupt source, thus
permitting higher priority interrupts to be serviced even if a lower priority interrupt is being
treated.
Internal interrupt sources can be programmed to be level sensitive or edge triggered. External
interrupt sources can be programmed to be positive-edge or negative-edge triggered or highlevel or low-level sensitive.
Important Features of the AIC are:
• Controls the Interrupt Lines (nIRQ and nFIQ) of an ARM Processor
• Thirty-two Individually Maskable and Vectored Interrupt Sources
– Source 0 is Reserved for the Fast Interrupt Input (FIQ)
– Source 1 is Reserved for System Peripherals (ST, RTC, PMC, DBGU…)
– Source 2 to Source 31 Control up to Thirty Embedded Peripheral Interrupts or
External Interrupts
– Programmable Edge-triggered or Level-sensitive Internal Sources
– Programmable Positive/Negative Edge-triggered or High/Low Level-sensitive
External Sources
• 8-level Priority Controller
– Drives the Normal Interrupt of the Processor
– Handles Priority of the Interrupt Sources 1 to 31
– Higher Priority Interrupts Can Be Served During Service of Lower Priority Interrupt
• Vectoring
– Optimizes Interrupt Service Routine Branch and Execution
– One 32-bit Vector Register per Interrupt Source
– Interrupt Vector Register Reads the Corresponding Current Interrupt Vector
• Protect Mode
– Easy Debugging by Preventing Automatic Operations when Protect ModeIs Are
Enabled
• General Interrupt Mask
– Provides Processor Synchronization on Events Without Triggering an Interrupt
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22.2
Block Diagram
Figure 22-1. Block Diagram
FIQ
AIC
ARM
Processor
IRQ0-IRQn
Up to
Thirty-two
Sources
Embedded
PeripheralEE
Embedded
nFIQ
nIRQ
Peripheral
Embedded
Peripheral
APB
22.3
Application Block Diagram
Figure 22-2. Description of the Application Block
OS-based Applications
Standalone
Applications
OS Drivers
RTOS Drivers
Hard Real Time Tasks
General OS Interrupt Handler
Advanced Interrupt Controller
External Peripherals
(External Interrupts)
Embedded Peripherals
22.4
AIC Detailed Block Diagram
Figure 22-3. AIC Detailed Block Diagram
Advanced Interrupt Controller
FIQ
PIO
Controller
Fast
Interrupt
Controller
External Source
Input Stage
ARM
Processor
nFIQ
nIRQ
IRQ0-IRQn
Interrupt
Priority
Controller
PIOIRQ
Internal Source
Input Stage
Processor
Clock
Power
Management
Controller
Embedded
Peripherals
User Interface
Wake Up
APB
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22.5
I/O Line Description
Table 22-1.
22.6
22.6.1
I/O Line Description
Pin Name
Pin Description
Type
FIQ
Fast Interrupt
Input
IRQ0 - IRQn
Interrupt 0 - Interrupt n
Input
Product Dependencies
I/O Lines
The interrupt signals FIQ and IRQ0 to IRQn are normally multiplexed through the PIO controllers. Depending on the features of the PIO controller used in the product, the pins must be
programmed in accordance with their assigned interrupt function. This is not applicable when
the PIO controller used in the product is transparent on the input path.
22.6.2
Power Management
The Advanced Interrupt Controller is continuously clocked. The Power Management Controller
has no effect on the Advanced Interrupt Controller behavior.
The assertion of the Advanced Interrupt Controller outputs, either nIRQ or nFIQ, wakes up the
ARM processor while it is in Idle Mode. The General Interrupt Mask feature enables the AIC to
wake up the processor without asserting the interrupt line of the processor, thus providing synchronization of the processor on an event.
22.6.3
Interrupt Sources
The Interrupt Source 0 is always located at FIQ. If the product does not feature an FIQ pin, the
Interrupt Source 0 cannot be used.
The Interrupt Source 1 is always located at System Interrupt. This is the result of the OR-wiring
of the system peripheral interrupt lines, such as the System Timer, the Real Time Clock, the
Power Management Controller and the Memory Controller. When a system interrupt occurs, the
service routine must first distinguish the cause of the interrupt. This is performed by reading successively the status registers of the above mentioned system peripherals.
The interrupt sources 2 to 31 can either be connected to the interrupt outputs of an embedded
user peripheral or to external interrupt lines. The external interrupt lines can be connected
directly, or through the PIO Controller.
The PIO Controllers are considered as user peripherals in the scope of interrupt handling.
Accordingly, the PIO Controller interrupt lines are connected to the Interrupt Sources 2 to 31.
The peripheral identification defined at the product level corresponds to the interrupt source
number (as well as the bit number controlling the clock of the peripheral). Consequently, to simplify the description of the functional operations and the user interface, the interrupt sources are
named FIQ, SYS, and PID2 to PID31.
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22.7
Functional Description
22.7.1
22.7.1.1
Interrupt Source Control
Interrupt Source Mode
The Advanced Interrupt Controller independently programs each interrupt source. The SRCTYPE field of the corresponding AIC_SMR (Source Mode Register) selects the interrupt
condition of each source.
The internal interrupt sources wired on the interrupt outputs of the embedded peripherals can be
programmed either in level-sensitive mode or in edge-triggered mode. The active level of the
internal interrupts is not important for the user.
The external interrupt sources can be programmed either in high level-sensitive or low level-sensitive modes, or in positive edge-triggered or negative edge-triggered modes.
22.7.1.2
Interrupt Source Enabling
Each interrupt source, including the FIQ in source 0, can be enabled or disabled by using the
command registers; AIC_IECR (Interrupt Enable Command Register) and AIC_IDCR (Interrupt
Disable Command Register). This set of registers conducts enabling or disabling in one instruction. The interrupt mask can be read in the AIC_IMR register. A disabled interrupt does not affect
servicing of other interrupts.
22.7.1.3
Interrupt Clearing and Setting
All interrupt sources programmed to be edge-triggered (including the FIQ in source 0) can be
individually set or cleared by writing respectively the AIC_ISCR and AIC_ICCR registers. Clearing or setting interrupt sources programmed in level-sensitive mode has no effect.
The clear operation is perfunctory, as the software must perform an action to reinitialize the
“memorization” circuitry activated when the source is programmed in edge-triggered mode.
However, the set operation is available for auto-test or software debug purposes. It can also be
used to execute an AIC-implementation of a software interrupt.
The AIC features an automatic clear of the current interrupt when the AIC_IVR (Interrupt Vector
Register) is read. Only the interrupt source being detected by the AIC as the current interrupt is
affected by this operation. (See Section 22.7.3.1 ”Priority Controller” on page 245.) The automatic clear reduces the operations required by the interrupt service routine entry code to reading
the AIC_IVR.)
The automatic clear of the interrupt source 0 is performed when AIC_FVR is read.
22.7.1.4
Interrupt Status
For each interrupt, the AIC operation originates in AIC_IPR (Interrupt Pending Register) and its
mask in AIC_IMR (Interrupt Mask Register). AIC_IPR enables the actual activity of the sources,
whether masked or not.
The AIC_ISR register reads the number of the current interrupt (See Section 22.7.3.1 ”Priority
Controller” on page 245.) and the register AIC_CISR gives an image of the signals nIRQ and
nFIQ driven on the processor.
Each status referred to above can be used to optimize the interrupt handling of the systems.
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22.7.1.5
Internal Interrupt Source Input Stage
Figure 22-4.
Internal Interrupt Source Input Stage
MCK
nIRQ
Maximum IRQ Latency = 3.5 Cycles
Peripheral Interrupt
Becomes Active
22.7.1.6
External Interrupt Source Input Stage
Figure 22-5. External Interrupt Source Input Stage
High/Lo w
AIC_SMRi
SRCTYPE
Level/
Edge
AIC_IPR
AIC_IMR
Source i
Fast Interrupt Controller
or
Priority Controller
AIC_IECR
Pos./Neg.
Edge
Detector
Set
AIC_ISCR
FF
Clear
AIC_IDCR
AIC_ICCR
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22.7.2
Interrupt Latencies
Global interrupt latencies depend on several parameters, including:
• The time the software masks the interrupts.
• Occurrence, either at the processor level or at the AIC level.
• The execution time of the instruction in progress when the interrupt occurs.
• The treatment of higher priority interrupts and the resynchronization of the hardware signals.
This section addresses only the hardware resynchronizations. It gives details of the latency
times between the event on an external interrupt leading in a valid interrupt (edge or level) or the
assertion of an internal interrupt source and the assertion of the nIRQ or nFIQ line on the processor. The resynchronization time depends on the programming of the interrupt source and on
its type (internal or external). For the standard interrupt, resynchronization times are given
assuming there is no higher priority in progress.
The PIO Controller multiplexing has no effect on the interrupt latencies of the external interrupt
sources.
22.7.2.1
External Interrupt Edge Triggered Source
Figure 22-6.
External Interrupt Edge Triggered Source
MCK
IRQ or FIQ
(Positive Edge)
IRQ or FIQ
(Negative Edge)
nIRQ
Maximum IRQ Latency = 4 Cycles
nFIQ
Maximum FIQ Latency = 4 Cycles
22.7.2.2
External Interrupt Level Sensitive Source
Figure 22-7.
External Interrupt Level Sensitive Source
MCK
IRQ or FIQ
(High Level)
IRQ or FIQ
(Low Level)
nIRQ
Maximum IRQ
Latency = 3 Cycles
nFIQ
Maximum FIQ
Latency = 3 cycles
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22.7.2.3
Internal Interrupt Edge Triggered Source
Figure 22-8.
Internal Interrupt Edge Triggered Source
MCK
nIRQ
Maximum IRQ Latency = 4.5 Cycles
Peripheral Interrupt
Becomes Active
22.7.2.4
Internal Interrupt Level Sensitive Source
Figure 22-9.
Internal Interrupt Level Sensitive Source
MCK
nIRQ
Maximum IRQ Latency = 3.5 Cycles
Peripheral Interrupt
Becomes Active
22.7.3
22.7.3.1
Normal Interrupt
Priority Controller
An 8-level priority controller drives the nIRQ line of the processor, depending on the interrupt
conditions occurring on the interrupt sources 1 to 31.
Each interrupt source has a programmable priority level of 7 to 0, which is user-definable by writing the PRIOR field of the corresponding AIC_SMR (Source Mode Register). Level 7 is the
highest priority and level 0 the lowest.
As soon as an interrupt condition occurs, as defined by the SRCTYPE field of the AIC_SVR
(Source Vector Register), the nIRQ line is asserted. As a new interrupt condition might have
happened on other interrupt sources since the nIRQ has been asserted, the priority controller
determines the current interrupt at the time the AIC_IVR (Interrupt Vector Register) is read. The
read of AIC_IVR is the entry point of the interrupt handling which allows the AIC to consider
that the interrupt has been taken into account by the software.
The current priority level is defined as the priority level of the current interrupt.
If several interrupt sources of equal priority are pending and enabled when the AIC_IVR is read,
the interrupt with the lowest interrupt source number is serviced first.
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The nIRQ line can be asserted only if an interrupt condition occurs on an interrupt source with a
higher priority. If an interrupt condition happens (or is pending) during the interrupt treatment in
progress, it is delayed until the software indicates to the AIC the end of the current service by
writing the AIC_EOICR (End of Interrupt Command Register). The write of AIC_EOICR is the
exit point of the interrupt handling.
22.7.3.2
Interrupt Nesting
The priority controller utilizes interrupt nesting in order for the highest priority interrupt to be handled during the service of lower priority interrupts. This requires the interrupt service routines of
the lower interrupts to re-enable the interrupt at the processor level.
When an interrupt of a higher priority happens during an already occurring interrupt service routine, the nIRQ line is re-asserted. If the interrupt is enabled at the core level, the current
execution is interrupted and the new interrupt service routine should read the AIC_IVR. At this
time, the current interrupt number and its priority level are pushed into an embedded hardware
stack, so that they are saved and restored when the higher priority interrupt servicing is finished
and the AIC_EOICR is written.
The AIC is equipped with an 8-level wide hardware stack in order to support up to eight interrupt
nestings pursuant to having eight priority levels.
22.7.3.3
Interrupt Vectoring
The interrupt handler addresses corresponding to each interrupt source can be stored in the registers AIC_SVR1 to AIC_SVR31 (Source Vector Register 1 to 31). When the processor reads
AIC_IVR (Interrupt Vector Register), the value written into AIC_SVR corresponding to the current interrupt is returned.
This feature offers a way to branch in one single instruction to the handler corresponding to the
current interrupt, as AIC_IVR is mapped at the absolute address 0xFFFF F100 and thus accessible from the ARM interrupt vector at address 0x0000 0018 through the following instruction:
LDR
PC,[PC,# -&F20]
When the processor executes this instruction, it loads the read value in AIC_IVR in its program
counter, thus branching the execution on the correct interrupt handler.
This feature is often not used when the application is based on an operating system (either real
time or not). Operating systems often have a single entry point for all the interrupts and the first
task performed is to discern the source of the interrupt.
However, it is strongly recommended to port the operating system on AT91 products by supporting the interrupt vectoring. This can be performed by defining all the AIC_SVR of the interrupt
source to be handled by the operating system at the address of its interrupt handler. When doing
so, the interrupt vectoring permits a critical interrupt to transfer the execution on a specific very
fast handler and not onto the operating system’s general interrupt handler. This facilitates the
support of hard real-time tasks (input/outputs of voice/audio buffers and software peripheral handling) to be handled efficiently and independently of the application running under an operating
system.
22.7.3.4
246
Interrupt Handlers
This section gives an overview of the fast interrupt handling sequence when using the AIC. It is
assumed that the programmer understands the architecture of the ARM processor, and especially the processor interrupt modes and the associated status bits.
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It is assumed that:
1. The Advanced Interrupt Controller has been programmed, AIC_SVR registers are
loaded with corresponding interrupt service routine addresses and interrupts are
enabled.
2. The instruction at the ARM interrupt exception vector address is required to work with
the vectoring
LDR PC, [PC, # -&F20]
When nIRQ is asserted, if the bit “I” of CPSR is 0, the sequence is as follows:
1. The CPSR is stored in SPSR_irq, the current value of the Program Counter is loaded in
the Interrupt link register (R14_irq) and the Program Counter (R15) is loaded with 0x18.
In the following cycle during fetch at address 0x1C, the ARM core adjusts R14_irq, decrementing it by four.
2. The ARM core enters Interrupt mode, if it has not already done so.
3. When the instruction loaded at address 0x18 is executed, the program counter is
loaded with the value read in AIC_IVR. Reading the AIC_IVR has the following effects:
a. Sets the current interrupt to be the pending and enabled interrupt with the highest
priority. The current level is the priority level of the current interrupt.
b.
De-asserts the nIRQ line on the processor. Even if vectoring is not used, AIC_IVR
must be read in order to de-assert nIRQ.
c.
Automatically clears the interrupt, if it has been programmed to be edge-triggered.
d. Pushes the current level and the current interrupt number on to the stack.
e. Returns the value written in the AIC_SVR corresponding to the current interrupt.
4. The previous step has the effect of branching to the corresponding interrupt service
routine. This should start by saving the link register (R14_irq) and SPSR_IRQ. The link
register must be decremented by four when it is saved if it is to be restored directly into
the program counter at the end of the interrupt. For example, the instruction SUB PC,
LR, #4 may be used.
5. Further interrupts can then be unmasked by clearing the “I” bit in CPSR, allowing reassertion of the nIRQ to be taken into account by the core. This can happen if an interrupt with a higher priority than the current interrupt occurs.
6. The interrupt handler can then proceed as required, saving the registers that will be
used and restoring them at the end. During this phase, an interrupt of higher priority
than the current level will restart the sequence from step 1.
Note:
If the interrupt is programmed to be level sensitive, the source of the interrupt must be cleared during this phase.
7. The “I” bit in CPSR must be set in order to mask interrupts before exiting to ensure that
the interrupt is completed in an orderly manner.
8. The End of Interrupt Command Register (AIC_EOICR) must be written in order to indicate to the AIC that the current interrupt is finished. This causes the current level to be
popped from the stack, restoring the previous current level if one exists on the stack. If
another interrupt is pending, with lower or equal priority than the old current level but
with higher priority than the new current level, the nIRQ line is re-asserted, but the interrupt sequence does not immediately start because the “I” bit is set in the core.
SPSR_irq is restored. Finally, the saved value of the link register is restored directly into
the PC. This has effect of returning from the interrupt to whatever was being executed
before, and of loading the CPSR with the stored SPSR, masking or unmasking the
interrupts depending on the state saved in SPSR_irq.
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Note:
22.7.4
The “I” bit in SPSR is significant. If it is set, it indicates that the ARM core was on the verge of
masking an interrupt when the mask instruction was interrupted. Hence, when SPSR is restored,
the mask instruction is completed (interrupt is masked).
Fast Interrupt
22.7.4.1
Fast Interrupt Source
The interrupt source 0 is the only source which can raise a fast interrupt request to the processor. The interrupt source 0 is generally connected to an FIQ pin of the product, either directly or
through a PIO Controller.
22.7.4.2
Fast Interrupt Control
The fast interrupt logic of the AIC has no priority controller. The mode of interrupt source 0 is
programmed with the AIC_SMR0 and the field PRIOR of this register is not used even if it reads
what has been written. The field SRCTYPE of AIC_SMR0 enables programming the fast interrupt source to be positive-edge triggered or negative-edge triggered or high-level sensitive or
low-level sensitive
Writing 0x1 in the AIC_IECR (Interrupt Enable Command Register) and AIC_IDCR (Interrupt
Disable Command Register) respectively enables and disables the fast interrupt. The bit 0 of
AIC_IMR (Interrupt Mask Register) indicates whether the fast interrupt is enabled or disabled.
22.7.4.3
Fast Interrupt Vectoring
The fast interrupt handler address can be stored in AIC_SVR0 (Source Vector Register 0). The
value written into this register is returned when the processor reads AIC_FVR (Fast Vector Register). This offers a way to branch in one single instruction to the interrupt handler, as AIC_FVR
is mapped at the absolute address 0xFFFF F104 and thus accessible from the ARM fast interrupt vector at address 0x0000 001C through the following instruction:
LDR
PC,[PC,# -&F20]
When the processor executes this instruction it loads the value read in AIC_FVR in its program
counter, thus branching the execution on the fast interrupt handler. It also automatically performs the clear of the fast interrupt source if it is programmed in edge-triggered mode.
22.7.4.4
Fast Interrupt Handlers
This section gives an overview of the fast interrupt handling sequence when using the AIC. It is
assumed that the programmer understands the architecture of the ARM processor, and especially the processor interrupt modes and associated status bits.
Assuming that:
1. The Advanced Interrupt Controller has been programmed, AIC_SVR0 is loaded with
the fast interrupt service routine address, and the interrupt source 0 is enabled.
2. The Instruction at address 0x1C (FIQ exception vector address) is required to vector
the fast interrupt:
LDR PC, [PC, # -&F20]
3. The user does not need nested fast interrupts.
When nFIQ is asserted if the bit “F” of CPSR is 0, the sequence is:
1. The CPSR is stored in SPSR_fiq, the current value of the program counter is loaded in
the FIQ link register (R14_FIQ) and the program counter (R15) is loaded with 0x1C. In
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the following cycle, during fetch at address 0x20, the ARM core adjusts R14_fiq, decrementing it by four.
2. The ARM core enters FIQ mode.
3. When the instruction loaded at address 0x1C is executed, the program counter is
loaded with the value read in AIC_FVR. Reading the AIC_FVR has effect of automatically clearing the fast interrupt, if it has been programmed to be edge triggered. In this
case only, it de-asserts the nFIQ line on the processor.
4. The previous step enables branching to the corresponding interrupt service routine. It is
not necessary to save the link register R14_fiq and SPSR_fiq if nested fast interrupts
are not needed.
5. The Interrupt Handler can then proceed as required. It is not necessary to save registers R8 to R13 because FIQ mode has its own dedicated registers and the user R8 to
R13 are banked. The other registers, R0 to R7, must be saved before being used, and
restored at the end (before the next step). Note that if the fast interrupt is programmed
to be level sensitive, the source of the interrupt must be cleared during this phase in
order to de-assert the interrupt source 0.
6. Finally, the Link Register R14_fiq is restored into the PC after decrementing it by four
(with instruction SUB PC, LR, #4 for example). This has the effect of returning from
the interrupt to whatever was being executed before, loading the CPSR with the SPSR
and masking or unmasking the fast interrupt depending on the state saved in the
SPSR.
Note:
The “F” bit in SPSR is significant. If it is set, it indicates that the ARM core was just about to mask
FIQ interrupts when the mask instruction was interrupted. Hence when the SPSR is restored, the
interrupted instruction is completed (FIQ is masked).
Another way to handle the fast interrupt is to map the interrupt service routine at the address of
the ARM vector 0x1C. This method does not use the vectoring, so that reading AIC_FVR must
be performed at the very beginning of the handler operation. However, this method saves the
execution of a branch instruction.
22.7.5
Protect Mode
The Protect Mode permits reading the Interrupt Vector Register without performing the associated automatic operations. This is necessary when working with a debug system. When a
debugger, working either with a Debug Monitor or the ARM processor's ICE, stops the applications and updates the opened windows, it might read the AIC User Interface and thus the IVR.
This has undesirable consequences:
• If an enabled interrupt with a higher priority than the current one is pending, it is stacked.
• If there is no enabled pending interrupt, the spurious vector is returned.
In either case, an End of Interrupt command is necessary to acknowledge and to restore the
context of the AIC. This operation is generally not performed by the debug system as the debug
system would become strongly intrusive and cause the application to enter an undesired state.
This is avoided by using the Protect Mode. Writing DBGM in AIC_DCR (Debug Control Register)
at 0x1 enables the Protect Mode.
When the Protect Mode is enabled, the AIC performs interrupt stacking only when a write access
is performed on the AIC_IVR. Therefore, the Interrupt Service Routines must write (arbitrary
data) to the AIC_IVR just after reading it. The new context of the AIC, including the value of the
Interrupt Status Register (AIC_ISR), is updated with the current interrupt only when AIC_IVR is
written.
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An AIC_IVR read on its own (e.g., by a debugger), modifies neither the AIC context nor the
AIC_ISR. Extra AIC_IVR reads perform the same operations. However, it is recommended to
not stop the processor between the read and the write of AIC_IVR of the interrupt service routine
to make sure the debugger does not modify the AIC context.
To summarize, in normal operating mode, the read of AIC_IVR performs the following operations within the AIC:
1. Calculates active interrupt (higher than current or spurious).
2. 2. Determines and returns the vector of the active interrupt.
3. Memorizes the interrupt.
4. Pushes the current priority level onto the internal stack.
5. Acknowledges the interrupt.
However, while the Protect Mode is activated, only operations 1 to 3 are performed when
AIC_IVR is read. Operations 4 and 5 are only performed by the AIC when AIC_IVR is written.
Software that has been written and debugged using the Protect Mode runs correctly in Normal
Mode without modification. However, in Normal Mode the AIC_IVR write has no effect and can
be removed to optimize the code.
22.7.6
Spurious Interrupt
The Advanced Interrupt Controller features protection against spurious interrupts. A spurious
interrupt is defined as being the assertion of an interrupt source long enough for the AIC to
assert the nIRQ, but no longer present when AIC_IVR is read. This is most prone to occur when:
• An external interrupt source is programmed in level-sensitive mode and an active level occurs
for only a short time.
• An internal interrupt source is programmed in level sensitive and the output signal of the
corresponding embedded peripheral is activated for a short time. (As in the case for the
Watchdog.)
• An interrupt occurs just a few cycles before the software begins to mask it, thus resulting in a
pulse on the interrupt source.
The AIC detects a spurious interrupt at the time the AIC_IVR is read while no enabled interrupt
source is pending. When this happens, the AIC returns the value stored by the programmer in
AIC_SPU (Spurious Vector Register). The programmer must store the address of a spurious
interrupt handler in AIC_SPU as part of the application, to enable an as fast as possible return to
the normal execution flow. This handler writes in AIC_EOICR and performs a return from
interrupt.
22.7.7
250
General Interrupt Mask
The AIC features a General Interrupt Mask bit to prevent interrupts from reaching the processor.
Both the nIRQ and the nFIQ lines are driven to their inactive state if the bit GMSK in AIC_DCR
(Debug Control Register) is set. However, this mask does not prevent waking up the processor if
it has entered Idle Mode. This function facilitates synchronizing the processor on a next event
and, as soon as the event occurs, performs subsequent operations without having to handle an
interrupt. It is strongly recommended to use this mask with caution.
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22.8
Advanced Interrupt Controller (AIC) User Interface
22.8.1
Base Address
The AIC is mapped at the address 0xFFFF F000. It has a total 4-Kbyte addressing space. This
permits the vectoring feature, as the PC-relative load/store instructions of the ARM processor
supports only an ± 4-Kbyte offset.
Table 22-2.
Offset
Register Mapping
Register
Name
Access
Reset Value
0000
Source Mode Register 0
AIC_SMR0
Read/Write
0x0
0x04
Source Mode Register 1
AIC_SMR1
Read/Write
0x0
–
–
–
–
–
0x7C
Source Mode Register 31
AIC_SMR31
Read/Write
0x0
0x80
Source Vector Register 0
AIC_SVR0
Read/Write
0x0
0x84
Source Vector Register 1
AIC_SVR1
Read/Write
0x0
–
–
–
AIC_SVR31
Read/Write
0x0
–
–
0xFC
Source Vector Register 31
0x100
Interrupt Vector Register
AIC_IVR
Read-only
0x0
0x104
Fast Interrupt Vector Register
AIC_FVR
Read-only
0x0
0x108
Interrupt Status Register
AIC_ISR
Read-only
0x0
0x10C
Interrupt Pending Register
AIC_IPR
Read-only
0x0(1)
0x110
Interrupt Mask Register
AIC_IMR
Read-only
0x0
0x114
Core Interrupt Status Register
AIC_CISR
Read-only
0x0
0x118
Reserved
–
–
–
0x11C
Reserved
–
–
–
0x120
Interrupt Enable Command Register
AIC_IECR
Write-only
–
0x124
Interrupt Disable Command Register
AIC_IDCR
Write-only
–
0x128
Interrupt Clear Command Register
AIC_ICCR
Write-only
–
0x12C
Interrupt Set Command Register
AIC_ISCR
Write-only
–
0x130
End of Interrupt Command Register
AIC_EOICR
Write-only
–
0x134
Spurious Interrupt Vector Register
AIC_SPU
Read/Write
0x0
0x138
Debug Control Register
AIC_DCR
Read/Write
0x0
0x13C
Reserved
–
–
–
Note:
1. The reset value of the Interrupt Pending Register depends on the level of the external interrupt source. All other sources are
cleared at reset, thus not pending.
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22.8.2
AIC Source Mode Register
Register Name:
AIC_SMR0..AIC_SMR31
Access Type:
Read/Write
Reset Value:
0x0
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
–
–
–
SRCTYPE
PRIOR
• PRIOR: Priority Level
Programs the priority level for all sources except FIQ source (source 0).
The priority level can be between 0 (lowest) and 7 (highest).
The priority level is not used for the FIQ in the related SMR register AIC_SMRx.
• SRCTYPE: Interrupt Source Type
The active level or edge is not programmable for the internal interrupt sources.
SRCTYPE
252
Internal Interrupt Sources
External Interrupt Sources
0
0
High-level Sensitive
Low-level Sensitive
0
1
Positive-edge Triggered
Negative-edge Triggered
1
0
High-level Sensitive
High-level Sensitive
1
1
Positive-edge Triggered
Positive-edge Triggered
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22.8.3
AIC Source Vector Register
Register Name:
AIC_SVR0..AIC_SVR31
Access Type:
Read/Write
Reset Value:
0x0
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
VECTOR
23
22
21
20
VECTOR
15
14
13
12
VECTOR
7
6
5
4
VECTOR
• VECTOR: Source Vector
The user may store in these registers the addresses of the corresponding handler for each interrupt source.
22.8.4
AIC Interrupt Vector Register
Register Name:
AIC_IVR
Access Type:
Read-only
Reset Value:
0
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
IRQV
23
22
21
20
IRQV
15
14
13
12
IRQV
7
6
5
4
IRQV
• IRQV: Interrupt Vector Register
The Interrupt Vector Register contains the vector programmed by the user in the Source Vector Register corresponding to
the current interrupt.
The Source Vector Register is indexed using the current interrupt number when the Interrupt Vector Register is read.
When there is no current interrupt, the Interrupt Vector Register reads the value stored in AIC_SPU.
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1768I–ATARM–09-Jul-09
22.8.5
AIC FIQ Vector Register
Register Name:
AIC_FVR
Access Type:
Read-only
Reset Value:
0
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
FIQV
23
22
21
20
FIQV
15
14
13
12
FIQV
7
6
5
4
FIQV
• FIQV: FIQ Vector Register
The FIQ Vector Register contains the vector programmed by the user in the Source Vector Register 0. When there is no
fast interrupt, the Fast Interrupt Vector Register reads the value stored in AIC_SPU.
22.8.6
AIC Interrupt Status Register
Register Name:
AIC_ISR
Access Type:
Read-only
Reset Value:
0
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
–
–
–
IRQID
• IRQID: Current Interrupt Identifier
The Interrupt Status Register returns the current interrupt source number.
254
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AT91RM9200
22.8.7
AIC Interrupt Pending Register
Register Name:
AIC_IPR
Access Type:
Read-only
Reset Value:
0
31
30
29
28
27
26
25
24
PID31
PID30
PID29
PID28
PID27
PID26
PID25
PID24
23
22
21
20
19
18
17
16
PID23
PID22
PID21
PID20
PID19
PID18
PID17
PID16
15
14
13
12
11
10
9
8
PID15
PID14
PID13
PID12
PID11
PID10
PID9
PID8
7
6
5
4
3
2
1
0
PID7
PID6
PID5
PID4
PID3
PID2
SYS
FIQ
• FIQ, SYS, PID2-PID31: Interrupt Pending
0 = Corresponding interrupt is no pending.
1 = Corresponding interrupt is pending.
22.8.8
AIC Interrupt Mask Register
Register Name:
AIC_IMR
Access Type:
Read-only
Reset Value:
0
31
30
29
28
27
26
25
24
PID31
PID30
PID29
PID28
PID27
PID26
PID25
PID24
23
22
21
20
19
18
17
16
PID23
PID22
PID21
PID20
PID19
PID18
PID17
PID16
15
14
13
12
11
10
9
8
PID15
PID14
PID13
PID12
PID11
PID10
PID9
PID8
7
6
5
4
3
2
1
0
PID7
PID6
PID5
PID4
PID3
PID2
SYS
FIQ
• FIQ, SYS, PID2-PID31: Interrupt Mask
0 = Corresponding interrupt is disabled.
1 = Corresponding interrupt is enabled.
255
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22.8.9
AIC Core Interrupt Status Register
Register Name:
AIC_CISR
Access Type:
Read-only
Reset Value:
0
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
–
–
–
–
–
–
NIRQ
NIFQ
• NFIQ: NFIQ Status
0 = nFIQ line is deactivated.
1 = nFIQ line is active.
• NIRQ: NIRQ Status
0 = nIRQ line is deactivated.
1 = nIRQ line is active.
22.8.10 AIC Interrupt Enable Command Register
Register Name:
AIC_IECR
Access Type:
Write-only
31
30
29
28
27
26
25
24
PID31
PID30
PID29
PID28
PID27
PID26
PID25
PID24
23
22
21
20
19
18
17
16
PID23
PID22
PID21
PID20
PID19
PID18
PID17
PID16
15
14
13
12
11
10
9
8
PID15
PID14
PID13
PID12
PID11
PID10
PID9
PID8
7
6
5
4
3
2
1
0
PID7
PID6
PID5
PID4
PID3
PID2
SYS
FIQ
• FIQ, SYS, PID2-PID3: Interrupt Enable
0 = No effect.
1 = Enables corresponding interrupt.
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22.8.11 AIC Interrupt Disable Command Register
Register Name:
AIC_IDCR
Access Type:
Write-only
31
30
29
28
27
26
25
24
PID31
PID30
PID29
PID28
PID27
PID26
PID25
PID24
23
22
21
20
19
18
17
16
PID23
PID22
PID21
PID20
PID19
PID18
PID17
PID16
15
14
13
12
11
10
9
8
PID15
PID14
PID13
PID12
PID11
PID10
PID9
PID8
7
6
5
4
3
2
1
0
PID7
PID6
PID5
PID4
PID3
PID2
SYS
FIQ
• FIQ, SYS, PID2-PID31: Interrupt Disable
0 = No effect.
1 = Disables corresponding interrupt.
22.8.12 AIC Interrupt Clear Command Register
Register Name:
AIC_ICCR
Access Type:
Write-only
31
30
29
28
27
26
25
24
PID31
PID30
PID29
PID28
PID27
PID26
PID25
PID24
23
22
21
20
19
18
17
16
PID23
PID22
PID21
PID20
PID19
PID18
PID17
PID16
15
14
13
12
11
10
9
8
PID15
PID14
PID13
PID12
PID11
PID10
PID9
PID8
7
6
5
4
3
2
1
0
PID7
PID6
PID5
PID4
PID3
PID2
SYS
FIQ
• FIQ, SYS, PID2-PID31: Interrupt Clear
0 = No effect.
1 = Clears corresponding interrupt.
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1768I–ATARM–09-Jul-09
22.8.13 AIC Interrupt Set Command Register
Register Name:
AIC_ISCR
Access Type:
Write-only
31
30
29
28
27
26
25
24
PID31
PID30
PID29
PID28
PID27
PID26
PID25
PID24
23
22
21
20
19
18
17
16
PID23
PID22
PID21
PID20
PID19
PID18
PID17
PID16
15
14
13
12
11
10
9
8
PID15
PID14
PID13
PID12
PID11
PID10
PID9
PID8
7
6
5
4
3
2
1
0
PID7
PID6
PID5
PID4
PID3
PID2
SYS
FIQ
• FIQ, SYS, PID2-PID31: Interrupt Set
0 = No effect.
1 = Sets corresponding interrupt.
22.8.14 AIC End of Interrupt Command Register
Register Name:
AIC_EOICR
Access Type:
Write-only
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
–
–
–
–
–
–
–
–
The End of Interrupt Command Register is used by the interrupt routine to indicate that the interrupt treatment is complete.
Any value can be written because it is only necessary to make a write to this register location to signal the end of interrupt
treatment.
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22.8.15 AIC Spurious Interrupt Vector Register
Register Name:
AIC_SPU
Access Type:
Read/Write
Reset Value:
0
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
SIQV
23
22
21
20
SIQV
15
14
13
12
SIQV
7
6
5
4
SIQV
• SIQV: Spurious Interrupt Vector Register
The use may store the address of a spurious interrupt handler in this register. The written value is returned in AIC_IVR in
case of a spurious interrupt and in AIC_FVR in case of a spurious fast interrupt.
259
1768I–ATARM–09-Jul-09
22.8.16 AIC Debug Control Register
Register Name:
AIC_DEBUG
Access Type:
Read/Write
Reset Value:
0
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
–
–
–
–
–
–
GMSK
PROT
• PROT: Protection Mode
0 = The Protection Mode is disabled.
1 = The Protection Mode is enabled.
• GMSK: General Mask
0 = The nIRQ and nFIQ lines are normally controlled by the AIC.
1 = The nIRQ and nFIQ lines are tied to their inactive state.
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23. Power Management Controller (PMC)
23.1
Overview
The Power Management Controller (PMC) generates all the clocks of a system thanks to the
integration of two oscillators and two PLLs.
The PMC provides clocks to the embedded processor and enables the idle mode by stopping
the processor clock until the next interrupt.
The PMC independently provides and controls up to thirty peripheral clocks and four programmable clocks that can be used as outputs on pins to feed external devices. The integration of the
PLLs supplies the USB devices and host ports with a 48 MHz clock, as required by the bus
speed, and the rest of the system with a clock at another frequency. Thus, the fully-featured
Power Management Controller optimizes power consumption of the whole system and supports
the Normal, Idle, Slow Clock and Standby operating modes.
The main features of the PMC are:
• Optimize the Power Consumption of the Whole System
• Embeds and Controls:
– One Main Oscillator and One Slow Clock Oscillator (32.768 kHz)
– Two Phase Locked Loops (PLLs) and Dividers
– Clock Prescalers
• Provides:
– the Processor Clock PCK
– the Master Clock MCK
– the USB Clocks, UHPCK and UDPCK, Respectively for the USB Host Port and the
USB Device Port
– Programmable Automatic PLL Switch-off in USB Device Suspend Conditions
– up to Thirty Peripheral Clocks
– up to Four Programmable Clock Outputs
• Four Operating Modes:
– Normal Mode, Idle Mode, Slow Clock Mode, Standby Mode
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23.2
23.2.1
Product Dependencies
I/O Lines
The Power Management Controller is capable of handling up to four Programmable Clocks,
PCK0 to PCK3.
A Programmable Clock is generally multiplexed on a PIO Controller. The user must first program
the PIO controllers to assign the pins of the Programmable Clock to its peripheral function.
23.2.2
Interrupt
The Power Management Controller has an interrupt line connected to the Advanced Interrupt
Controller (AIC). Handling the PMC interrupt requires programming the AIC before configuring
the PMC.
23.2.3
Oscillator and PLL Characteristics
The electrical characteristics of the embedded oscillators and PLLs are product-dependent,
even if the way to control them is similar.
All of the parameters for both oscillators and the PLLs are given in the DC Characteristics section of the product datasheet. These figures are used not only for the hardware design, as they
affect the external components to be connected to the pins, but also the software configuration,
as they determine the waiting time for the startup and lock times to be programmed.
23.2.4
Peripheral Clocks
The Power Management Controller provides and controls up to thirty peripheral clocks. The bit
number permitting the control of a peripheral clock is the Peripheral ID of the embedded
peripheral.
When the Peripheral ID does not correspond to a peripheral, either because this is an external
interrupt or because there are less than thirty peripherals, the control bits of the Peripheral ID
are not implemented in the PMC and programming them has no effect on the behavior of the
PMC.
23.2.5
USB Clocks
The Power Management Controller provides and controls two USB Clocks, the UHPCK for the
USB Host Port, and the UDPCK for the USB Device.
If the product does not embed either the USB Host Port or the USB Device Port, the associated
control bits and registers are not implemented in the PMC and programming them has no effect
on the behavior of the PMC.
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23.3
Block Diagram
Figure 23-1. Power Management Controller Block Diagram
Processor
Clock
Power Management Controller
Processor
Clock
Controller
Clock Generator
XIN32
Slow Clock
Oscillator
Idle Mode
Slow
Clock
SLCK
Main
Oscillator
Main
Clock
Master Clock Controller
SLCK
Main Clock
PLLA Clock
PLLB Clock
Prescaler
/2,/4,...,/64
PMCIRQ
/1,/2,/3,/4
ARM9-systems
only
MCK
(Continuous)
Memory Controller
PLL and
Divider A
PLLA
Clock
Peripherals
Clock Controller
PLLRCB
AIC
Divider
XOUT
PLLRCA
ARM920T
Processor
IRQ or FIQ
XOUT32
XIN
Processor
Clock
ARM7
Processor
PLL and
Divider B
PLLB
Clock
30
MCK
(Individually
Switchable)
Embedded
Peripherals
ON/OFF
UDPCK
PLLB
Clock
USB Clock
Controller
UDP
Suspend
UHPCK
ON/OFF
UHP
Programmable Clock Controller
SLCK
Main Clock
PLLA Clock
PLLB Clock
PCK0-PCK3
Prescaler
4
/2,/4,...,/64
PIO
Programmable
Clocks
ST
User Interface
Slow
Clock
SLCK
SLCK
RTC
APB
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23.4
23.4.1
Functional Description
Operating Modes Definition
The following operating modes are supported by the PMC and offer different power consumption
levels and event response latency times:
• Normal Mode: The ARM processor clock is enabled and peripheral clocks are enabled
depending on application requirements.
• Idle Mode: The ARM processor clock is disabled and waiting for the next interrupt (or a main
reset). The peripheral clocks are enabled depending on application requirements. PDC
transfers are still possible.
• Slow Clock Mode: Slow clock mode is similar to normal mode, but the main oscillator and the
PLL are switched off to save power and the processor and the peripherals run in Slow Clock
mode. Note that slow clock mode is the mode selected after the reset.
• Standby Mode: Standby mode is a combination of Slow Clock mode and Idle Mode. It
enables the processor to respond quickly to a wake-up event by keeping power consumption
very low.
23.4.2
Clock Definitions
The Power Management Controller provides the following clocks:
• Slow Clock (SLCK), typically at 32.768 kHz, is the only permanent clock within the system.
• Master Clock (MCK), programmable from a few hundred Hz to the maximum operating
frequency of the device. It is available to the modules running permanently, such as the AIC
and the Memory Controller.
• Processor Clock (PCK), typically the Master Clock for ARM7-based systems and a faster
clock on ARM9-based systems, switched off when entering idle mode.
• Peripheral Clocks, typically MCK, provided to the embedded peripherals (USART, SSC, SPI,
TWI, TC, MCI, etc.) and independently controllable. In order to reduce the number of clock
names in a product, the Peripheral Clocks are named MCK in the product datasheet.
• UDP Clock (UDPCK), typically at 48 MHz, required by the USB Device Port operations.
• UHP Clock (UHPCK), typically at 48 MHz, required by the USB Host Port operations.
• Programmable Clock Outputs (PCK0 to PCK3) can be selected from the clocks provided by
the clock generator and driven on the PCK0 to PCK3 pins.
23.4.3
Clock Generator
The Clock Generator embeds:
• the Slow Clock Oscillator
• the Main Oscillator
• two PLL and divider blocks, A and B
The Clock Generator may optionally integrate a divider by 2. The ARM7-based systems generally embed PLLs able to output between 20 MHz and 100 MHz and do not embed the divider
by 2. The ARM9-based systems generally embed PLLs able to output between 80 MHz and
180 MHz. As the 48 MHz required by the USB cannot be reached by such a PLL, the optional
divider by 2 is implemented.
The block diagram of the Clock Generator is shown in Figure 23-2.
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Figure 23-2. Clock Generator Block Diagram
Clock Generator
XIN32
Slow
Clock
SLCK
Slow Clock
Oscillator
XOUT32
XIN
Main
Oscillator
Main
Clock
XOUT
Main Clock
Frequency
Counter
Divider A
PLL A
Divider B
PLL B
PLLA
Clock
PLLRCA
/2
(optional)
PLLB
Clock
PLLRCB
23.4.4
23.4.4.1
Slow Clock Oscillator
Slow Clock Oscillator Connection
The Clock Generator integrates a low-power 32.768 kHz oscillator. The XIN32 and XOUT32
pins must be connected to a 32.768 kHz crystal. Two external capacitors must be wired as
shown in Figure 23-3.
Figure 23-3. Typical Slow Clock Oscillator Connection
XIN32
XOUT32
GNDOSC
32.768 kHz
Crystal
CL1
23.4.4.2
CL2
Slow Clock Oscillator Startup Time
The startup time of the Slow Clock Oscillator is given in the DC Characteristics section of the
product datasheet. As it is often higher than 500 ms and the processor requires an assertion of
the reset until it has stabilized, the user must implement an external reset supervisor covering
this startup time. However, this startup is only required in case of cold reset, i.e., in case of system power-up. When a warm reset occurs, the length of the reset pulse may be much lower. For
further details, see Section 15. “AT91RM9200 Reset Controller” on page 117.
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1768I–ATARM–09-Jul-09
23.4.5
Main Oscillator
Figure 23-4 shows the Main Oscillator block diagram.
Figure 23-4. Main Oscillator Block Diagram
MOSCEN
XIN
Main
Oscillator
Main
Clock
XOUT
OSCOUNT
Main
Oscillator
Counter
Slow
Clock
Main Clock
Frequency
Counter
23.4.5.1
MOSCS
MAINF
MAINRDY
Main Oscillator Connections
The Clock Generator integrates a Main Oscillator that is designed for a 3 to 20 MHz fundamental
crystal. The typical crystal connection is illustrated in Figure 23-5. The 1 kΩ resistor is only
required for crystals with frequencies lower than 8 MHz. The oscillator contains internal capacitors on each XIN and XOUT pin. For further details on the electrical characteristics of the Main
Oscillator, see the section “AT91RM9200 Electrical Characteristics”.
Figure 23-5. Typical Crystal Connection
XIN
XOUT
GNDOSC
1K
CL1
CL2
23.4.5.2
Main Oscillator Startup Time
The startup time of the Main Oscillator is given in the DC Characteristics section of the product
datasheet. The startup time depends on the crystal frequency and decreases when the frequency rises.
23.4.5.3
Main Oscillator Control
To minimize the power required to start up the system, the Main Oscillator is disabled after reset
and the Slow Clock mode is selected.
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The software enables or disables the Main Oscillator so as to reduce power consumption by
clearing the MOSCEN bit in the Main Oscillator Register (CKGR_MOR). When disabling the
Main Oscillator by clearing the MOSCEN bit in CKGR_MOR, the MOSCS bit in PMC_SR is
automatically cleared indicating the Main Clock is off.
When enabling the Main Oscillator, the user must initiate the Main Oscillator counter with a value
corresponding to the startup time of the oscillator. This startup time depends on the crystal frequency connected to the main oscillator. When the MOSCEN bit and the OSCOUNT are written
in CKGR_MOR to enable the Main Oscillator, the MOSCS bit is cleared and the counter starts
counting down on Slow Clock from the OSCOUNT value. Since the OSCOUNT value is coded
with 8 bits, the maximum startup time is about 62 ms.
When the counter reaches 0, the MOSCS bit is set, indicating that the Main Clock is valid. Setting the MOSCS bit in PMC_IMR can trigger an interrupt to the processor on this event.
23.4.5.4
Main Clock Frequency Counter
The Main Oscillator features a Main Clock frequency counter that provides the quartz frequency
connected to the Main Oscillator. Generally, this value is known by the system designer; however, it is useful for the boot program to configure the device with the correct clock speed,
independently of the application.
The Main Clock frequency counter starts incrementing at the Main Clock speed after the next rising edge of the Slow Clock as soon as the Main Oscillator is stable, i.e., as soon as the MOSCS
bit is set. Then, at the 16th falling edge of Slow Clock, the bit MAINRDY in CKGR_MCFR (Main
Clock Frequency Register) is set and the counter stops counting. Its value can be read in the
MAINF field of CKGR_MCFR and gives the number of Main Clock cycles during 16 periods of
Slow Clock, so that the frequency of the crystal connected on the Main Oscillator can be
determined.
23.4.5.5
Main Oscillator Bypass
The user can input a clock on the device instead of connecting a crystal. In this case, the user
has to provide the external clock signal on the pin XIN. The input characteristics of the XIN pin
under these conditions are given in the product Electrical Characteristics section. The programmer has to be sure not to modify the MOSCEN bit in the Main Oscillator Register (CKGR_MOR).
This bit must remain at 0, its reset value, for the external clock to operate properly. While this bit
is at 0, the pin XIN is pulled down by a 500 kΩ resistor in parallel with a 40 pF capacitor.
The external clock signal must meet the requirements relating to the power supply VDDPLL (i.e.,
between 1.65V and 1.95V) and cannot exceed 50 MHz.
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1768I–ATARM–09-Jul-09
23.4.6
Divider and PLL Blocks
The Clock Generator features two Divider/PLL Blocks that generates a wide range of frequencies. Additionally, they provide a 48 MHz signal to the embedded USB device and/or host ports,
regardless of the frequency of the Main Clock.
Figure 23-6 shows the block diagram of the divider and PLL blocks.
Figure 23-6. Divider and PLL Blocks Block Diagram
DIVB
Main
Clock
MULB
Divider B
OUTB
PLL B
Output
PLL B
PLLRCB
DIVA
MULA
Divider A
OUTA
PLL A
PLL A
Output
PLLRCA
PLLBCOUNT
PLL B
Counter
LOCKB
PLLACOUNT
Slow
Clock
23.4.6.1
PLL A
Counter
LOCKA
PLL Filters
The two PLLs require connection to an external second-order filter through the pins PLLRC. Figure 23-7 shows a schematic of these filters.
Figure 23-7. PLL Capacitors and Resistors
PLLRC
PLL
R
C2
C1
GND
Values of R, C1 and C2 to be connected to the PLLRC pins must be calculated as a function of
the PLL input frequency, the PLL output frequency and the phase margin. A trade-off has to be
found between output signal overshoot and startup time.
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23.4.6.2
PLL Source Clock
The source of PLLs A and B is respectively the output of Divider A, i.e. the Main Clock divided by
DIVA, and the output of Divider B, i.e. the Main Clock divided by DIVB.
As the input frequency of the PLLs is limited, the user has to make sure that the programming of
DIVA and DIVB are compliant with the input frequency range of the PLLs, which is given in the
DC Characteristics section of the product datasheet.
23.4.6.3
Divider and Phase Lock Loop Programming
The two dividers increase the accuracy of the PLLA and the PLLB clocks independently of the
input frequency.
The Main Clock can be divided by programming the DIVB field in CKGR_PLLBR and the DIVA
field in CKGR_PLLAR. Each divider can be set between 1 and 255 in steps of 1. When the DIVA
and DIVB fields are set to 0, the output of the divider and the PLL outputs A and B are a continuous signal at level 0. On reset, the DIVA and DIVB fields are set to 0, thus both PLL input
clocks are set to 0.
The two PLLs of the clock generator allow multiplication of the divider’s outputs. The PLLA and
the PLLB clock signals have a frequency that depends on the respective source signal frequency and on the parameters DIV (DIVA, DIVB) and MUL (MULA, MULB). The factor applied to
the source signal frequency is (MUL + 1)/DIV. When MULA or MULB is written to 0, the corresponding PLL is disabled and its power consumption is saved. Re-enabling the PLLA or the
PLLB can be performed by writing a value higher than 0 in the MULA or MULB field,
respectively.
Whenever a PLL is re-enabled or one of its parameters is changed, the LOCKA or LOCKB bit in
PMC_SR is automatically cleared. The values written in the PLLACOUNT or PLLBCOUNT fields
in CKGR_PPLAR and CKGR_PLLBR, respectively, are loaded in the corresponding PLL counter. The PLL counter then decrements at the speed of the Slow Clock until it reaches 0. At this
time, the corresponding LOCK bit is set in PMC_SR and can trigger an interrupt to the processor. The user has to load the number of Slow Clock cycles required to cover the PLL transient
time into the PLLACOUNT and PLLBCOUNT field. The transient time depends on the PLL filters. The initial state of the PLL and its target frequency can be calculated using a specific tool
provided by Atmel.
23.4.6.4
PLLB Divider by 2
In ARM9-based systems, the PLLB clock may be divided by two. This divider can be enabled by
setting the bit USB_96M of CKGR_PLLBR. In this case, the divider by 2 is enabled and the
PLLB must be programmed to output 96 MHz and not 48 MHz, thus ensuring correct operation
of the USB bus.
269
1768I–ATARM–09-Jul-09
23.4.7
Clock Controllers
The Power Management Controller provides the clocks to the different peripherals of the system, either internal or external. It embeds the following elements:
• the Master Clock Controller, which selects the Master Clock.
• the Processor Clock Controller, which implements the Idle Mode.
• the Peripheral Clock Controller, which provides power saving by controlling clocks of the
embedded peripherals.
• the USB Clock Controller, which distributes the 48 MHz clock to the USB controllers.
• the Programmable Clock Controller, which allows generation of up to four programmable
clock signals on external pins.
23.4.7.1
Master Clock Controller
The Master Clock Controller provides selection and division of the Master Clock (MCK). MCK is
the clock provided to all the peripherals and the memory controller.
The Master Clock is selected from one of the clocks provided by the Clock Generator. Selecting
the Slow Clock enables Slow Clock Mode by providing a 32.768 kHz signal to the whole device.
Selecting the Main Clock saves power consumption of both PLLs, but prevents using the USB
ports. Selecting the PLLB Clock saves the power consumption of the PLLA by running the processor and the peripheral at 48 MHz required by the USB ports. Selecting the PLLA Clock runs
the processor and the peripherals at their maximum speed while running the USB ports at 48
MHz.
The Master Clock Controller is made up of a clock selector and a prescaler, as shown in Figure
23-8. It also contains an optional Master Clock divider in products integrating an ARM9 processor. This allows the processor clock to be faster than the Master Clock.
The Master Clock selection is made by writing the CSS field (Clock Source Selection) in
PMC_MCKR (Master Clock Register). The prescaler supports the division by a power of 2 of the
selected clock between 1 and 64. The PRES field in PMC_MCKR programs the prescaler.
When the Master Clock divider is implemented, it can be programmed between 1 and 4 through
the MDIV field in PMC_MCKR.
Each time PMC_MCKR is written to define a new Master Clock, the MCKRDY bit is cleared in
PMC_SR. It reads 0 until the Master Clock is established. Then, the MCKRDY bit is set and can
trigger an interrupt to the processor. This feature is useful when switching from a high-speed
clock to a lower one to inform the software when the change is actually done.
Note:
270
A new value to be written in PMC_MCKR must not be the same as the current value in
PMC_MCKR.
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Figure 23-8. Master Clock Controller
MDIV
CD
PRES
Main Clock
PLLB Clock
MCK
To the Processor
Clock Controller
SLCK
PLLA Clock
Master
Clock
Divider
ARM9 Products
Master Clock
Prescaler
ARM7 Products
MCK
To the Processor
Clock Controller
23.4.7.2
Processor Clock Controller
The PMC features a Processor Clock Controller that implements the Idle Mode. The Processor
Clock can be enabled and disabled by writing the System Clock Enable (PMC_SCER) and System Clock Disable Registers (PMC_SCDR). The status of this clock (at least for debug purpose)
can be read in the System Clock Status Register (PMC_SCSR).
Processor Clock Source
The clock provided to the processor is determined by the Master Clock controller. On ARM7based systems, the Processor Clock source is directly the Master Clock.
On ARM9-based systems, the Processor Clock source might be 2, 3 or 4 times the Master
Clock. This ratio value is determined by programming the field MDIV of the Master Clock Register (PMC_MCKR).
Idle Mode
The Processor Clock is enabled after a reset and is automatically re-enabled by any enabled
interrupt. The Idle Mode is achieved by disabling the Processor Clock, which is automatically reenabled by any enabled fast or normal interrupt, or by the reset of the product.
When the Processor Clock is disabled, the current instruction is finished before the clock is
stopped, but this does not prevent data transfers from other masters of the system bus.
23.4.7.3
Peripheral Clock Controller
The PMC controls the clocks of each embedded peripheral. The user can individually enable
and disable the Master Clock on the peripherals by writing into the Peripheral Clock Enable
(PMC_PCER) and Peripheral Clock Disable (PMC_PCDR) registers. The status of the peripheral clock activity can be read in the Peripheral Clock Status Register (PMC_PCSR).
When a peripheral clock is disabled, the clock is immediately stopped. When the clock is reenabled, the peripheral resumes action where it left off. The peripheral clocks are automatically
disabled after a reset.
In order to stop a peripheral, it is recommended that the system software wait until the peripheral
has executed its last programmed operation before disabling the clock. This is to avoid data corruption or erroneous behavior of the system.
The bit number within the Peripheral Clock Control registers (PMC_PCER, PMC_PCDR, and
PMC_PCSR) is the Peripheral Identifier defined at the product level. Generally, the bit number
corresponds to the interrupt source number assigned to the peripheral.
271
1768I–ATARM–09-Jul-09
23.4.7.4
USB Clock Controller
If using one of the USB ports, the user has to program the Divider and PLL B block to output a
48 MHz signal with an accuracy of ± 0.25%.
When the clock for the USB is stable, the USB device and host clocks, UDPCK and UHPCK, can
be enabled. They can be disabled when the USB transactions are finished, so that the power
consumption generated by the 48 MHz signal on these peripherals is saved.
The USB ports require both the 48 MHz signal and the Master Clock. The Master Clock may be
controlled via the Peripheral Clock Controller.
USB Device Clock Control
The USB Device Port clock UDPCK can be enabled by writing 1 at the UDP bit in PMC_SCER
(System Clock Enable Register) and disabled by writing 1 at the bit UDP in PMC_SCDR (System Clock Disable Register). The activity of UDPCK is shown in the bit UDP of PMC_SCSR
(System Clock Status Register).
USB Device Port Suspend
When the USB Device Port detects a suspend condition, the 48 MHz clock is automatically disabled, i.e., the UDP bit in PMC_SCSR is cleared. It is also possible to automatically disable the
Master Clock provided to the USB Device Port on a suspend condition. The MCKUDP bit in
PMC_SCSR configures this feature and can be set or cleared by writing one in the same bit of
PMC_SCER and PMC_SCDR.
USB Host Clock Control
The USB Host Port clock UHPCK can be enabled by writing 1 at the UHP bit in PMC_SCER
(System Clock Enable Register) and disabled by writing 1 at the UHP bit in PMC_SCDR (System Clock Disable Register). The activity of UDPCK is shown in the bit UHP of PMC_SCSR
(System Clock Status Register).
23.4.7.5
Programmable Clock Output Controller
The PMC controls up to four signals to be output on external pins PCK0 to PCK3. Each signal
can be independently programmed via the registers PMC_PCK0 to PMC_PCK3.
PCK0 to PCK3 can be independently selected between the four clocks provided by the Clock
Generator by writing the CSS field in PMC_PCK0 to PMC_PCK3. Each output signal can also
be divided by a power of 2 between 1 and 64 by writing the field PRES (Prescaler) in
PMC_PCK0 to PMC_PCK3.
Each output signal can be enabled and disabled by writing 1 in the corresponding bit PCK0 to
PCK3 of PMC_SCER and PMC_SCDR, respectively. Status of the active programmable output
clocks are given in the bits PCK0 to PCK3 of PMC_SCSR (System Clock Status Register).
Moreover, like the MCK, a status bit in PMC_SR indicates that the Programmable Clock is actually what has been programmed in the Programmable Clock registers.
As the Programmable Clock Controller does not manage with glitch prevention when switching
clocks, it is strongly recommended to disable the Programmable Clock before any configuration
change and to re-enable it after the change is actually performed.
Note also that it is required to assign the pin to the Programmable Clock operation in the PIO
Controller to enable the signal to be driven on the pin.
272
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23.5
23.5.1
Clock Switching Details
Master Clock Switching Timings
Table 23-1 gives the worst case timing required for the Master Clock to switch from one selected
clock to another one. This is in the event that the prescaler is de-activated. When the prescaler
is activated, an additional time of 64 clock cycles of the new selected clock has to be added.
Table 23-1.
Clock Switching Timings (Worst Case)
From
Main Clock
SLCK
PLLA Clock
PLLB Clock
–
4 x SLCK +
2.5 x Main Clock
3 x PLLA Clock +
4 x SLCK +
1 x Main Clock
3 x PLLB Clock +
4 x SLCK +
1 x Main Clock
0.5 x Main Clock +
4.5 x SLCK
–
3 x PLLA Clock +
5 x SLCK
3 x PLLB Clock +
5 x SLCK
PLLA Clock
0.5 x Main Clock +
4 x SLCK +
PLLACOUNT x SLCK +
2.5 x PLLA Clock
2.5 x PLLA Clock +
5 x SLCK +
PLLACOUNT x SLCK
2.5 x PLLA Clock +
4 x SLCK +
PLLB COUNT x SLCK
3 x PLLA Clock +
4 x SLCK +
1.5 x PLLA Clock
PLLB Clock
0.5 x Main Clock +
4 x SLCK +
PLLBCOUNT x SLCK +
2.5 x PLLB Clock
2.5 x PLLB Clock +
5 x SLCK +
PLLBCOUNT x SLCK
3 x PLLB Clock +
4 x SLCK +
1.5 x PLLB Clock
2.5 x PLLB Clock +
4 x SLCK +
PLLACOUNT x SLCK
To
Main Clock
SLCK
23.5.2
Clock Switching Waveforms
Figure 23-9. Switch Master Clock from Slow Clock to PLLA Clock
Slow Clock
PLLA Clock
LOCK A
MCKRDY
Master Clock
Write PMC_MCKR
273
1768I–ATARM–09-Jul-09
Figure 23-10. Switch Master Clock from Main Clock to Slow Clock
Slow Clock
Main Clock
MCKRDY
Master Clock
Write PMC_MCKR
Figure 23-11. Change PLLA Programming
Slow Clock
PLLA Clock
LOCKA
MCKRDY
Master Clock
Slow Clock
Write CKGR_PLLAR
274
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Figure 23-12. Programmable Clock Output Programming
PLLA Clock
PCKRDY
PCKx Output
Write PMC_PCKX
Write PMC_SCER
Write PMC_SCDR
PLLA Clock is selected
PCKx is enabled
PCKx is disabled
275
1768I–ATARM–09-Jul-09
23.6
Power Management Controller (PMC) User Interface
Table 23-2.
Register Mapping
Offset
Register
Name
Access
Reset Value
0x0000
System Clock Enable Register
PMC_SCER
Write-only
–
0x0004
System Clock Disable Register
PMC_SCDR
Write-only
–
0x0008
System Clock Status Register
PMC _SCSR
Read-only
0x01
0x000C
Reserved
–
–
0x0010
Peripheral Clock Enable Register
PMC _PCER
Write-only
–
0x0014
Peripheral Clock Disable Register
PMC_PCDR
Write-only
–
0x0018
Peripheral Clock Status Register
PMC_PCSR
Read-only
0x0
0x001C
Reserved
–
–
0x0020
Main Oscillator Register
CKGR_MOR
ReadWrite
0x0
0x0024
Main Clock Frequency Register
CKGR_MCFR
Read-only
-
0x0028
PLL A Register
CKGR_PLLAR
ReadWrite
0x3F00
0x002C
PLL B Register
CKGR_PLLBR
ReadWrite
0x3F00
0x0030
Master Clock Register
PMC_MCKR
Read/Write
0x00
0x0034
Reserved
–
–
–
0x0038
Reserved
–
–
–
0x003C
Reserved
–
–
–
0x0040
Programmable Clock 0 Register
PMC_PCK0
Read/Write
0x0
0x0044
Programmable Clock 1 Register
PMC_PCK1
Read/Write
0x0
0x0048
Programmable Clock 2 Register
PMC_PCK2
Read/Write
0x0
0x004C
Programmable Clock 3 Register
PMC_PCK3
Read/Write
0x0
0x0050
Reserved
–
–
–
0x0054
Reserved
–
–
–
0x0058
Reserved
–
–
–
0x005C
Reserved
–
–
–
0x0060
Interrupt Enable Register
PMC_IER
Write-only
--
0x0064
Interrupt Disable Register
PMC_IDR
Write-only
--
0x0068
Status Register
PMC_SR
Read-only
--
0x006C
Interrupt Mask Register
PMC_IMR
Read-only
0x0
276
–
–
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1768I–ATARM–09-Jul-09
AT91RM9200
23.6.1
PMC System Clock Enable Register
Register Name:
PMC_SCER
Access Type:
Write-only
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
–
PCK3
PCK2
PCK1
PCK0
7
6
5
4
3
2
1
0
–
–
–
UHP
–
MCKUDP
UDP
PCK
• PCK: Processor Clock Enable
0 = No effect.
1 = Enables the Processor Clock.
• UDP: USB Device Port Clock Enable
0 = No effect.
1 = Enables the 48 MHz clock of the USB Device Port.
• MCKUDP: USB Device Port Master Clock Automatic Disable on Suspend Enable
0 = No effect.
1 = Enables the automatic disable of the Master Clock of the USB Device Port when a suspend condition occurs.
• UHP: USB Host Port Clock Enable
0 = No effect.
1 = Enables the 48 MHz clock of the USB Host Port.
• PCK0...PCK3: Programmable Clock Output Enable
0 = No effect.
1 = Enables the corresponding Programmable Clock output.
277
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23.6.2
PMC System Clock Disable Register
Register Name:
PMC_SCDR
Access Type:
Write-only
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
–
PCK3
PCK2
PCK1
PCK0
7
6
5
4
3
2
1
0
–
–
–
UHP
–
MCKUDP
UDP
PCK
• PCK: Processor Clock Disable
0 = No effect.
1 = Disables the Processor Clock.
• UDP: USB Device Port Clock Disable
0 = No effect.
1 = Disables the 48 MHz clock of the USB Device Port.
• MCKUDP: USB Device Port Master Clock Automatic Disable on Suspend Disable
0 = No effect.
1 = Disables the automatic disable of the Master Clock of the USB Device Port when a suspend condition occurs.
• UHP: USB Host Port Clock Disable
0 = No effect.
1 = Disables the 48 MHz clock of the USB Host Port.
• PCK0...PCK3: Programmable Clock Output Disable
0 = No effect.
1 = Disables the corresponding Programmable Clock output.
278
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23.6.3
PMC System Clock Status Register
Register Name:
PMC_SCSR
Access Type:
Read-only
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
–
PCK3
PCK2
PCK1
PCK0
7
6
5
4
3
2
1
0
–
–
–
UHP
–
MCKUDP
UDP
PCK
• PCK: Processor Clock Status
0 = The Processor Clock is disabled.
1 = The Processor Clock is enabled.
• UDP: USB Device Port Clock Status
0 = The 48 MHz clock of the USB Device Port is disabled.
1 = The 48 MHz clock of the USB Device Port is enabled.
• MCKUDP: USB Device Port Master Clock Automatic Disable on Suspend Status
0 = The automatic disable of the Master clock of the USB Device Port when suspend condition occurs is disabled.
1 = The automatic disable of the Master clock of the USB Device Port when suspend condition occurs is enabled.
• UHP: USB Host Port Clock Status
0 = The 48 MHz clock of the USB Host Port is disabled.
1 = The 48 MHz clock of the USB Host Port is enabled.
• PCK0...PCK3: Programmable Clock Output Status
0 = The corresponding Programmable Clock output is disabled.
1 = The corresponding Programmable Clock output is enabled.
279
1768I–ATARM–09-Jul-09
23.6.4
PMC Peripheral Clock Enable Register
Register Name:
PMC_PCER
Access Type:
Write-only
31
30
29
28
27
26
25
24
PID31
PID30
PID29
PID28
PID27
PID26
PID25
PID24
23
22
21
20
19
18
17
16
PID23
PID22
PID21
PID20
PID19
PID18
PID17
PID16
15
14
13
12
11
10
9
8
PID15
PID14
PID13
PID12
PID11
PID10
PID9
PID8
7
6
5
4
3
2
1
0
PID7
PID6
PID5
PID4
PID3
PID2
–
–
• PID2...PID31: Peripheral Clock Enable
0 = No effect.
1 = Enables the corresponding peripheral clock.
280
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1768I–ATARM–09-Jul-09
AT91RM9200
23.6.5
PMC Peripheral Clock Disable Register
Register Name:
PMC_PCDR
Access Type:
Write-only
31
30
29
28
27
26
25
24
PID31
PID30
PID29
PID28
PID27
PID26
PID25
PID24
23
22
21
20
19
18
17
16
PID23
PID22
PID21
PID20
PID19
PID18
PID17
PID16
15
14
13
12
11
10
9
8
PID15
PID14
PID13
PID12
PID11
PID10
PID9
PID8
7
6
5
4
3
2
1
0
PID7
PID6
PID5
PID4
PID3
PID2
–
–
• PID2...PID31: Peripheral Clock Disable
0 = No effect.
1 = Disables the corresponding peripheral clock.
281
1768I–ATARM–09-Jul-09
23.6.6
PMC Peripheral Clock Status Register
Register Name:
PMC_PCSR
Access Type:
Read-only
31
30
29
28
27
26
25
24
PID31
PID30
PID29
PID28
PID27
PID26
PID25
PID24
23
22
21
20
19
18
17
16
PID23
PID22
PID21
PID20
PID19
PID18
PID17
PID16
15
14
13
12
11
10
9
8
PID15
PID14
PID13
PID12
PID11
PID10
PID9
PID8
7
6
5
4
3
2
1
0
PID7
PID6
PID5
PID4
PID3
PID2
–
–
• PID2...PID31: Peripheral Clock Status
0 = The corresponding peripheral clock is disabled.
1 = The corresponding peripheral clock is enabled.
282
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AT91RM9200
23.6.7
PMC Clock Generator Main Oscillator Register
Register Name:
CKGR_MOR
Access Type:
Read/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
3
–
2
–
1
OSCBYPASS
0
MOSCEN
OSCOUNT
7
–
6
–
5
–
4
–
• MOSCEN: Main Oscillator Enable
A crystal must be connected between XIN and XOUT.
0 = The Main Oscillator is disabled.
1 = The Main Oscillator is enabled. OSCBYPASS must be set to 0.
When MOSCEN is set, the MOSCS flag is set once the Main Oscillator startup time is achieved.
• OSCBYPASS: Oscillator Bypass
0 = No effect.
1 = The Main Oscillator is bypassed. MOSCEN must be set to 0. An external clock must be connected on XIN.
When OSCBYPASS is set, the MOSCS flag in PMC_SR is automatically set.
Clearing MOSCEN and OSCBYPASS bits allows resetting the MOSCS flag.
• OSCOUNT: Main Oscillator Start-up Time
Specifies the number of Slow Clock cycles multiplied by 8 for the Main Oscillator start-up time.
283
1768I–ATARM–09-Jul-09
23.6.8
PMC Clock Generator Main Clock Frequency Register
Register Name:
CKGR_MCFR
Access Type:
Read-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
MAINRDY
15
14
13
12
11
10
9
8
3
2
1
0
MAINF
7
6
5
4
MAINF
• MAINF: Main Clock Frequency
Gives the number of Main Clock cycles within 16 Slow Clock periods.
• MAINRDY: Main Clock Ready
0 = MAINF value is not valid or the Main Oscillator is disabled.
1 = The Main Oscillator has been enabled previously and MAINF value is available.
284
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23.6.9
PMC Clock Generator PLL A Register
Register Name:
CKGR_PLLAR
Access Type:
Read/Write
31
–
30
–
29
1
28
–
27
–
26
25
MULA
24
23
22
21
20
19
18
17
16
11
10
9
8
2
1
0
MULA
15
14
13
12
OUTA
PLLACOUNT
7
6
5
4
3
DIVA
Possible limitations on PLL A input frequencies and multiplier factors should be checked before using the Clock Generator.
Value to be written in CKGR_PLLAR must not be the same as current value in CKGR_PLLAR.
• DIVA: Divider A
DIVA
Divider Selected
0
Divider output is 0
1
Divider is bypassed
2 - 255
Divider output is the Main Clock divided by DIVA.
• PLLACOUNT: PLL A Counter
Specifies the number of Slow Clock cycles before the LOCKA bit is set in PMC_SR after CKGR_PLLAR is written.
• OUTA: PLL A Clock Frequency Range
OUTA
PLL A Frequency Output Range
0
0
80 MHz to 160 MHz
0
1
Reserved
1
0
150 MHz to 180 MHz
1
1
Reserved
• MULA: PLL A Multiplier
0 = The PLL A is deactivated.
1 up to 2047 = The PLL A Clock frequency is the PLL A input frequency multiplied by MULA + 1.
285
1768I–ATARM–09-Jul-09
23.6.10 PMC Clock Generator PLL B Register
Register Name:
CKGR_PLLBR
Access Type:
Read/Write
31
–
30
–
29
–
28
USB_96M
27
–
26
25
MULB
24
23
22
21
20
19
18
17
16
11
10
9
8
2
1
0
MULB
15
14
13
12
OUTB
7
PLLBCOUNT
6
5
4
3
DIVB
Possible limitations on PLL B input frequencies and multiplier factors should be checked before using the Clock Generator.
Value to be written in CKGR_PLLBR must not be the same as current value in CKGR_PLLBR.
• DIVB: Divider B
DIVB
Divider Selected
0
Divider output is 0
1
Divider is bypassed
2 - 255
Divider output is the selected clock divided by DIVB.
• PLLBCOUNT: PLL B Counter
Specifies the number of slow clock cycles before the LOCKB bit is set in PMC_SR after CKGR_PLLBR is written.
• OUTB: PLL B Clock Frequency Range
OUTB
PLL B Clock Frequency Range
0
0
80 MHz to 160 MHz
0
1
Reserved
1
0
150 MHz to 180 MHz
1
1
Reserved
• MULB: PLL B Multiplier
0 = The PLL B is deactivated.
1 up to 2047 = The PLL B Clock frequency is the PLL B input frequency multiplied by MULB + 1.
• USB_96M: Divider by 2 Enable (only on ARM9-based Systems)
0 = USB ports clocks are PLL B Clock, therefore the PMC Clock Generator must be programmed for the PLL B Clock to be
48 MHz.
1 = USB ports clocks are PLL B Clock divided by 2, therefore the PMC Clock Generator must be programmed for the PLL
B Clock to be 96 MHz.
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23.6.11 PMC Master Clock Register
Register Name:
PMC_MCKR
Access Type:
Read/Write
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
–
–
–
–
–
–
7
6
5
4
3
2
–
–
8
MDIV
1
PRES
0
CSS
Note: Value to be written in PMC_MCKR must not be the same as current value in PMC_MCKR.
• CSS: Master Clock Selection
CSS
Clock Source Selection
0
0
Slow Clock is selected
0
1
Main Clock is selected
1
0
PLL A Clock is selected
1
1
PLL B Clock is selected
• PRES: Master Clock Prescaler
PRES
Master Clock
0
0
0
Selected clock
0
0
1
Selected clock divided by 2
0
1
0
Selected clock divided by 4
0
1
1
Selected clock divided by 8
1
0
0
Selected clock divided by 16
1
0
1
Selected clock divided by 32
1
1
0
Selected clock divided by 64
1
1
1
Reserved
• MDIV: Master Clock Division (on ARM9-based systems only)
0 = The Master Clock and the Processor Clock are the same.
1 = The Processor Clock is twice as fast as the Master Clock.
2 = The Processor Clock is three times faster than the Master Clock.
3 = The Processor Clock is four times faster than the Master Clock.
287
1768I–ATARM–09-Jul-09
23.6.12 PMC Programmable Clock Register 0 to 3
Register Name:
PMC_PCK0..PMC_PCK3
Access Type:
Read/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
–
–
–
–
–
–
–
–
4
3
2
1
7
6
5
–
–
–
0
PRES
CSS
• CSS: Master Clock Selection
CSS
Clock Source Selection
0
0
Slow Clock is selected
0
1
Main Clock is selected
1
0
PLL A Clock is selected
1
1
PLL B Clock is selected
• PRES: Programmable Clock Prescaler
PRES
288
Master Clock
0
0
0
Selected clock
0
0
1
Selected clock divided by 2
0
1
0
Selected clock divided by 4
0
1
1
Selected clock divided by 8
1
0
0
Selected clock divided by 16
1
0
1
Selected clock divided by 32
1
1
0
Selected clock divided by 64
1
1
1
Reserved
AT91RM9200
1768I–ATARM–09-Jul-09
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23.6.13 PMC Interrupt Enable Register
Register Name:
PMC_IER
Access Type:
Write-only
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
–
PCK3RDY
PCK2RDY
PCK1RDY
PCK0RDY
7
6
5
4
3
2
1
0
–
–
–
–
MCKRDY
LOCKB
LOCKA
MOSCS
• MOSCS: Main Oscillator Status
• LOCKA: PLL A Lock
• LOCKB: PLL B Lock
• MCKRDY: Master Clock Ready
• PCK0RDY - PCK3RDY: Programmable Clock Ready
0 = No effect.
1 = Enables the corresponding interrupt.
289
1768I–ATARM–09-Jul-09
23.6.14 PMC Interrupt Disable Register
Register Name:
PMC_IDR
Access Type:
Write-only
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
–
PCK3RDY
PCK2RDY
PCK1RDY
PCK0RDY
7
6
5
4
3
2
1
0
–
–
–
–
MCKRDY
LOCKB
LOCKA
MOSCS
• MOSCS: Main Oscillator Status
• LOCKA: PLL A Lock
• LOCKB: PLL B Lock
• MCKRDY: Master Clock Ready
• PCK0RDY - PCK3RDY: Programmable Clock Ready
0 = No effect.
1 = Disables the corresponding interrupt.
290
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23.6.15 PMC Status Register
Register Name:
PMC_SR
Access Type:
Read-only
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
–
PCK3RDY
PCK2RDY
PCK1RDY
PCK0RDY
7
6
5
4
3
2
1
0
–
–
–
–
MCKRDY
LOCKB
LOCKA
MOSCS
• MOSCS: MOSCS Flag Status
0 = Main oscillator is not stabilized.
1 = Main oscillator is stabilized.
• LOCKA: PLLA Lock Status
0 = PLLL A is not locked
1 = PLL A is locked.
• LOCKB: PLLB Lock Status
0 = PLL B is not locked.
1 = PLL B is locked.
• MCKRDY: Master Clock Status
0 = MCK is not ready.
1 = MCK is ready.
• PCK0RDY - PCK3RDY: Programmable Clock Ready Status
0 = Programmable Clock 0 to 3 is not ready.
1 = Programmable Clock 0 to 3 is ready.
291
1768I–ATARM–09-Jul-09
23.6.16 PMC Interrupt Mask Register
Register Name:
PMC_IMR
Access Type:
Read-only
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
–
PCK3RDY
PCK2RDY
PCK1RDY
PCK0RDY
7
6
5
4
3
2
1
0
–
–
–
–
MCKRDY
LOCKB
LOCKA
MOSCS
• MOSCS: Main Oscillator Status
• LOCKA: PLL A Lock
• LOCKB: PLL B Lock
• MCKRDY: Master Clock Ready
• PCK0RDY - PCK3RDY: Programmable Clock Ready
• MOSCS: MOSCS Interrupt Mask
0 = The corresponding interrupt is enabled.
1 = The corresponding interrupt is disabled.
292
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24. System Timer (ST)
24.1
Overview
The System Timer (ST) module integrates three different free-running timers:
• A Period Interval Timer (PIT) that sets the time base for an operating system.
• A Watchdog Timer (WDT) with system reset capabilities in case of software deadlock.
• A Real-Time Timer (RTT) counting elapsed seconds.
These timers count using the Slow Clock provided by the Power Management Controller. Typically, this clock has a frequency of 32.768 kHz, but the System Timer might be configured to
support another frequency.
The System Timer provides an interrupt line connected to one of the sources of the Advanced
Interrupt Controller (AIC). Interrupt handling requires programming the AIC before configuring
the System Timer. Usually, the System Timer interrupt line is connected to the first interrupt
source line and shares this entry with the Debug Unit (DBGU) and the Real Time Clock (RTC).
This sharing requires the programmer to determine the source of the interrupt when the source 1
is triggered.
Important features of the System Timer include:
• One Period Interval Timer, 16-bit Programmable Counter
• One Watchdog Timer, 16-bit Programmable Counter
• One Real-time Timer, 20-bit Free-running Counter
• Interrupt Generation on Event
24.2
Block Diagram
Figure 24-1. System Timer Block Diagram
APB
System Timer
Periodic Interval Timer
Real-Time Timer
Power
Management
Controller
SLCK
Watchdog Timer
STIRQ
Advanced Interrupt Controller
293
1768I–ATARM–09-Jul-09
24.3
Application Block Diagram
Figure 24-2. Application Block Diagram
24.4
OS or RTOS
Scheduler
Date, Time
and Alarm
Manager
System Survey
Manager
PIT
RTT
WDT
Product Dependencies
24.4.1
Power Management
The System Timer is continuously clocked at 32768 Hz. The power management controller has
no effect on the system timer behavior.
24.4.2
Interrupt Sources
The System Timer interrupt is generally connected to the source 1 of the Advanced Interrupt
Controller. This interrupt line is the result of the OR-wiring of the system peripheral interrupt lines
(System Timer, Real Time Clock, Power Management Controller, Memory Controller). When a
system interrupt happens, the service routine must first determine the cause of the interrupt.
This is accomplished by reading successively the status registers of the above mentioned system peripherals.
24.5
Functional Description
24.5.1
System Timer Clock
The System Timer uses only the SLCK clock so that it is capable to provide periodic, watchdog,
second change or alarm interrupt even if the Power Management Controller is programmed to
put the product in Slow Clock Mode. If the product has the capability to back up the Slow Clock
oscillator and the System Timer, the System Timer can continue to operate.
24.5.2
Period Interval Timer (PIT)
The Period Interval Timer can be used to provide periodic interrupts for use by operating systems. The reset value of the PIT is 0 corresponding to the maximum value. It is built around a
16-bit down counter, which is preloaded by a value programmed in ST_PIMR (Period Interval
Mode Register). When the PIT counter reaches 0, the bit PITS is set in ST_SR (Status Register), and an interrupt is generated if it is enabled.
The counter is then automatically reloaded and restarted. Writing to the ST_PIMR at any time
immediately reloads and restarts the down counter with the new programmed value.
Warning: If ST_PIMR is programmed with a period less or equal to the current MCK period, the
update of the PITS status bit and its associated interrupt generation are unpredictable.
294
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Figure 24-3. Period Interval Timer
PIV
SLCK
Slow Clock
24.5.3
16-bit
Down Counter
PITS
Watchdog Timer (WDT)
The Watchdog Timer can be used to prevent system lock-up if the software becomes trapped in
a deadlock. It is built around a 16-bit down counter loaded with the value defined in ST_WDMR
(Watchdog Mode Register).
At reset, the value of the ST_WDMR is 0x00020000, corresponding to the maximum value of the
counter.
It uses the Slow Clock divided by 128 to establish the maximum watchdog period to be 256 seconds (with a typical slow clock of 32.768 kHz).
In normal operation, the user reloads the Watchdog at regular intervals before the timer overflow
occurs, by setting the bit WDRST in the ST_CR (Control Register).
If an overflow does occur, the watchdog timer:
• Sets the WDOVF bit in ST_SR (Status Register), from which an interrupt can be generated.
• Generates an internal reset if the parameter RSTEN in ST_WDMR is set.
• Reloads and restarts the down counter.
Writing the ST_WDMR does not reload or restart the down counter. When the ST_CR is written
the watchdog counter is immediately reloaded from ST_WDMR and restarted and the Slow
Clock 128 divider is also immediately reset and restarted.
Figure 24-4. Watchdog Timer
WV
SLCK
1/128
16-bit Down
Counter
WDOVF Status
RSTEN
WDRST
24.5.4
Internal Reset
Real-time Timer (RTT)
The Real-Time Timer is used to count elapsed seconds. It is built around a 20-bit counter fed by
Slow Clock divided by a programmable value. At reset, this value is set to 0x8000, corresponding to feeding the real-time counter with a 1 Hz signal when the Slow Clock is 32.768 Hz. The
20-bit counter can count up to 1048576 seconds, corresponding to more than 12 days, then roll
over to 0.
The Real-Time Timer value can be read at any time in the register ST_CRTR (Current Real-time
Register). As this value can be updated asynchronously to the master clock, it is advisable to
read this register twice at the same value to improve accuracy of the returned value.
295
1768I–ATARM–09-Jul-09
This current value of the counter is compared with the value written in the alarm register
ST_RTAR (Real-time Alarm Register). If the counter value matches the alarm, the bit ALMS in
TC_SR is set. The alarm register is set to its maximum value, corresponding to 0, after a reset.
The bit RTTINC in ST_SR is set each time the 20-bit counter is incremented. This bit can be
used to start an interrupt, or generate a one-second signal.
Writing the ST_RTMR immediately reloads and restarts the clock divider with the new programmed value. This also resets the 20-bit counter.
Warning: If RTPRES is programmed with a period less or equal to the current MCK period, the
update of the RTTINC and ALMS status bits and their associated interrupt generation are
unpredictable.
Figure 24-5. Real Time Timer
RTPRES
SLCK
16-bit
Divider
RTTINC
20-bit
Counter
=
ALMS
ALMV
24.6
System Timer (ST) User Interface
Table 24-1.
Register Mapping
Offset
Register
Name
Access
Reset Value
0x0000
Control Register
ST_CR
Write-only
–
0x0004
Period Interval Mode Register
ST_PIMR
Read/Write
0x00000000
0x0008
Watchdog Mode Register
ST_WDMR
Read/Write
0x00020000
0x000C
Real-time Mode Register
ST_RTMR
Read/Write
0x00008000
0x0010
Status Register
ST_SR
Read-only
–
0x0014
Interrupt Enable Register
ST_IER
Write-only
–
0x0018
Interrupt Disable Register
ST_IDR
Write-only
–
0x001C
Interrupt Mask Register
ST_IMR
Read-only
0x0
0x0020
Real-time Alarm Register
ST_RTAR
Read/Write
0x0
0x0024
Current Real-time Register
ST_CRTR
Read-only
0x0
296
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24.6.1
ST Control Register
Register Name:
ST_CR
Access Type:
Write-only
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
WDRST
• WDRST: Watchdog Timer Restart
0 = No effect.
1 = Reload the start-up value in the watchdog timer.
24.6.2
ST Period Interval Mode Register
Register Name:
ST_PIMR
Access Type:
Read/Write
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
PIV
PIV
• PIV: Period Interval Value
Defines the value loaded in the 16-bit counter of the period interval timer. The maximum period is obtained by programming
PIV at 0x0 corresponding to 65536 slow clock cycles.
297
1768I–ATARM–09-Jul-09
24.6.3
ST Watchdog Mode Register
Register Name:
ST_WDMR
Access Type:
Read/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
3
2
1
0
WDV
7
6
5
4
WDV
• WDV: Watchdog Counter Value
Defines the value loaded in the 16-bit counter. The maximum period is obtained by programming WDV to 0x0 corresponding to 65536 x 128 slow clock cycles.
• RSTEN: Reset Enable
0 = No reset is generated when a watchdog overflow occurs.
1 = An internal reset is generated when a watchdog overflow occurs.
24.6.4
ST Real-Time Mode Register
Register Name:
ST_RTMR
Access Type:
Read/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
3
2
1
0
RTPRES
7
6
5
4
RTPRES
• RTPRES: Real-time Timer Prescaler Value
Defines the number of SLCK periods required to increment the real-time timer. The maximum period is obtained by programming RTPRES to 0x0 corresponding to 65536 slow clock cycles.
24.6.5
ST Status Register
Register Name:
ST_SR
298
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AT91RM9200
Access Type:
Read-only
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
ALMS
2
RTTINC
1
WDOVF
0
PITS
• PITS: Period Interval Timer Status
0 = The period interval timer has not reached 0 since the last read of the Status Register.
1 = The period interval timer has reached 0 since the last read of the Status Register.
• WDOVF: Watchdog Overflow
0 = The watchdog timer has not reached 0 since the last read of the Status Register.
1 = The watchdog timer has reached 0 since the last read of the Status Register.
• RTTINC: Real-time Timer Increment
0 = The real-time timer has not been incremented since the last read of the Status Register.
1 = The real-time timer has been incremented since the last read of the Status Register.
• ALMS: Alarm Status
0 = No alarm compare has been detected since the last read of the Status Register.
1 = Alarm compare has been detected since the last read of the Status Register.
299
1768I–ATARM–09-Jul-09
24.6.6
ST Interrupt Enable Register
Register Name:
ST_IER
Access Type:
Write-only
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
ALMS
2
RTTINC
1
WDOVF
0
PITS
• PITS: Period Interval Timer Status Interrupt Enable
• WDOVF: Watchdog Overflow Interrupt Enable
• RTTINC: Real-time Timer Increment Interrupt Enable
• ALMS: Alarm Status Interrupt Enable
0 = No effect.
1 = Enables the corresponding interrupt.
300
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24.6.7
ST Interrupt Disable Register
Register Name:
ST_IDR
Access Type:
Write-only
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
ALMS
2
RTTINC
1
WDOVF
0
PITS
• PITS: Period Interval Timer Status Interrupt Disable
• WDOVF: Watchdog Overflow Interrupt Disable
• RTTINC: Real-time Timer Increment Interrupt Disable
• ALMS: Alarm Status Interrupt Disable
0 = No effect.
1 = Disables the corresponding interrupt.
301
1768I–ATARM–09-Jul-09
24.6.8
ST Interrupt Mask Register
Register Name:
ST_IMR
Access Type:
Read-only
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
ALMS
2
RTTINC
1
WDOVF
0
PITS
• PITS: Period Interval Timer Status Interrupt Mask
• WDOVF: Watchdog Overflow Interrupt Mask
• RTTINC: Real-time Timer Increment Interrupt Mask
• ALMS: Alarm Status Interrupt Mask
0 = The corresponding interrupt is disabled.
1 = The corresponding interrupt is enabled.
24.6.9
ST Real-time Alarm Register
Register Name:
ST_RTAR
Access Type:
Read/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
3
2
1
0
ALMV
ALMV
7
6
5
4
ALMV
• ALMV: Alarm Value
Defines the alarm value compared with the real-time timer. The maximum delay before ALMS status bit activation is
obtained by programming ALMV to 0x0 corresponding to 1048576 seconds.
24.6.10 ST Current Real-Time Register
Register Name:
ST_CRTR
302
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Access Type:
Read-only
31
–
30
–
29
–
28
–
27
–
26
–
23
–
22
–
21
–
20
–
19
18
15
14
13
12
25
–
24
–
17
16
CRTV
11
10
9
8
3
2
1
0
CRTV
7
6
5
4
CRTV
• CRTV: Current Real-time Value
Returns the current value of the real-time timer.
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25. Real Time Clock (RTC)
25.1
Overview
The Real-time Clock (RTC) peripheral is designed for very low power consumption.
It combines a complete time-of-day clock with alarm and a two-hundred-year Gregorian calendar, complemented by a programmable periodic interrupt. The alarm and calendar registers are
accessed by a 32-bit data bus.
The time and calendar values are coded in binary-coded decimal (BCD) format. The time format
can be 24-hour mode or 12-hour mode with an AM/PM indicator.
Updating time and calendar fields and configuring the alarm fields are performed by a parallel
capture on the 32-bit data bus. An entry control is performed to avoid loading registers with
incompatible BCD format data or with an incompatible date according to the current
month/year/century.
Important features of the RTC include:
• Low Power Consumption
• Full Asynchronous Design
• Two Hundred Year Calendar
• Programmable Periodic Interrupt
• Alarm and Update Parallel Load
• Control of Alarm and Update Time/Calendar Data In
25.2
Block Diagram
Figure 25-1. RTC Block Diagram
25.3
Crystal Oscillator: SLCK
32768 Divider
Bus Interface
Bus Interface
Time
Date
Entry
Control
Interrupt
Control
RTC Interrupt
Product Dependencies
25.3.1
Power Management
The Real-time Clock is continuously clocked at 32768 Hz. The Power Management Controller
has no effect on RTC behavior.
25.3.2
Interrupt
The RTC Interrupt is connected to interrupt source 1 (IRQ1) of the advanced interrupt controller.
This interrupt line is due to the OR-wiring of the system peripheral interrupt lines (System Timer,
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1768I–ATARM–09-Jul-09
Real Time Clock, Power Management Controller, Memory Controller, etc.). When a system
interrupt occurs, the service routine must first determine the cause of the interrupt. This is done
by reading the status registers of the above system peripherals successively.
25.4
Functional Description
The RTC provides a full binary-coded decimal (BCD) clock that includes century (19/20), year
(with leap years), month, date, day, hours, minutes and seconds.
The valid year range is 1900 to 2099, a two-hundred-year Gregorian calendar achieving full Y2K
compliance.
The RTC can operate in 24-hour mode or in 12-hour mode with an AM/PM indicator.
Corrections for leap years are included (all years divisible by 4 being leap years, including year
2000). This is correct up to the year 2099.
After hardware reset, the calendar is initialized to Thursday, January 1, 1998.
25.4.1
Reference Clock
The reference clock is Slow Clock (SLCK). It can be driven by the Atmel cell OSC55 or OSC56
(or an equivalent cell) and an external 32.768 kHz crystal.
During low power modes of the processor (idle mode), the oscillator runs and power consumption is critical. The crystal selection has to take into account the current consumption for power
saving and the frequency drift due to temperature effect on the circuit for time accuracy.
25.4.2
Timing
The RTC is updated in real time at one-second intervals in normal mode for the counters of seconds, at one-minute intervals for the counter of minutes and so on.
Due to the asynchronous operation of the RTC with respect to the rest of the chip, to be certain
that the value read in the RTC registers (century, year, month, date, day, hours, minutes, seconds) are valid and stable, it is necessary to read these registers twice. If the data is the same
both times, then it is valid. Therefore, a minimum of two and a maximum of three accesses are
required.
25.4.3
Alarm
The RTC has five programmable fields: month, date, hours, minutes and seconds.
Each of these fields can be enabled or disabled to match the alarm condition:
• If all the fields are enabled, an alarm flag is generated (the corresponding flag is asserted
and an interrupt generated if enabled) at a given month, date, hour/minute/second.
• If only the “seconds” field is enabled, then an alarm is generated every minute.
Depending on the combination of fields enabled, a large number of possibilities are available to
the user ranging from minutes to 365/366 days.
25.4.4
Error Checking
Verification on user interface data is performed when accessing the century, year, month, date,
day, hours, minutes, seconds and alarms. A check is performed on illegal BCD entries such as
illegal date of the month with regard to the year and century configured.
If one of the time fields is not correct, the data is not loaded into the register/counter and a flag is
set in the validity register. The user can not reset this flag. It is reset as soon as an acceptable
306
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
value is programmed. This avoids any further side effects in the hardware. The same procedure
is done for the alarm.
The following checks are performed:
1. Century (check if it is in range 19 - 20)
2. Year (BCD entry check)
3. Date (check range 01 - 31)
4. Month (check if it is in BCD range 01 - 12, check validity regarding “date”)
5. Day (check range 1 - 7)
6. Hour (BCD checks: in 24-hour mode, check range 00 - 23 and check that AM/PM flag is
not set if RTC is set in 24-hour mode; in 12-hour mode check range 01 - 12)
7. Minute (check BCD and range 00 - 59)
8. Second (check BCD and range 00 - 59)
Note:
25.4.5
If the 12-hour mode is selected by means of the RTC_MODE register, a 12-hour value can be programmed and the returned value on RTC_TIME will be the corresponding 24-hour value. The
entry control checks the value of the AM/PM indicator (bit 22 of RTC_TIME register) to determine
the range to be checked.
Updating Time/Calendar
To update any of the time/calendar fields, the user must first stop the RTC by setting the corresponding field in the Control Register. Bit UPDTIM must be set to update time fields (hour,
minute, second) and bit UPDCAL must be set to update calendar fields (century, year, month,
date, day).
Then the user must poll or wait for the interrupt (if enabled) of bit ACKUPD in the Status Register. Once the bit reads 1, the user must clear this status bit by writing ACKUPD to 1 in
RTC_SCCR, and write to the appropriate register.
Once the update is finished, the user must reset (0) UPDTIM and/or UPDCAL in the Control
Register.
The time and date are stopped when entering the programming mode.
It is highly recommended to prepare all the fields to update prior to entering the programming
mode, to avoid a time slip in case the user would stay in the calendar update phase for several
tens of seconds or more.
In successive update operations, the user must wait at least one second after resetting the
UPDTIM/UPDCAL bit in the RTC_CR (Control Register) before setting these bits again. This is
done by waiting for the SEC flag in the Status Register before setting UPDTIM/UPDCAL bit.
After resetting UPDTIM/UPDCAL, the SEC flag must also be cleared.
307
1768I–ATARM–09-Jul-09
25.5
Real Time Clock (RTC) User Interface
Table 25-1.
Offset
308
RTC Register Mapping
Register
Register Name
Read/Write
Reset
0x00
RTC Control Register
RTC_CR
Read/Write
0x0
0x04
RTC Mode Register
RTC_MR
Read/Write
0x0
0x08
RTC Time Register
RTC_TIMR
Read/Write
0x0
0x0C
RTC Calendar Register
RTC_CALR
Read/Write
0x01819819
0x10
RTC Time Alarm Register
RTC_TIMALR
Read/Write
0x0
0x14
RTC Calendar Alarm Register
RTC_CALALR
Read/Write
0x01010000
0x18
RTC Status Register
RTC_SR
Read only
0x0
0x1C
RTC Status Clear Command Register
RTC_SCCR
Write only
---
0x20
RTC Interrupt Enable Register
RTC_IER
Write only
---
0x24
RTC Interrupt Disable Register
RTC_IDR
Write only
---
0x28
RTC Interrupt Mask Register
RTC_IMR
Read only
0x0
0x2C
RTC Valid Entry Register
RTC_VER
Read only
0x0
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25.5.1
Name:
RTC Control Register
RTC_CR
Access Type:
Read/Write
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
–
–
–
–
–
–
15
14
13
12
11
10
–
–
–
–
–
–
16
CALEVSEL
9
8
TIMEVSEL
7
6
5
4
3
2
1
0
–
–
–
–
–
–
UPDCAL
UPDTIM
• UPDTIM: Update Request Time Register
0 = No effect.
1 = Stops the RTC time counting.
Time counting consists of second, minute and hour counters. Time counters can be programmed once this bit is set and
acknowledged by the bit ACKUPD of the Status Register.
• UPDCAL: Update Request Calendar Register
0 = No effect.
1 = Stops the RTC calendar counting.
Calendar counting consists of day, date, month, year and century counters. Calendar counters can be programmed once
this bit is set.
• TIMEVSEL: Time Event Selection
The event that generates the flag TIMEV in RTC_SR (Status Register) depends on the value of TIMEVSEL.
0 = Minute change.
1 = Hour change.
2 = Every day at midnight.
3 = Every day at noon.
• CALEVSEL: Calendar Event Selection
The event that generates the flag CALEV in RTC_SR depends on the value of CALEVSEL.
0 = Week change (every Monday at time 00:00:00).
1 = Month change (every 01 of each month at time 00:00:00).
2, 3 = Year change (every January 1 at time 00:00:00).
309
1768I–ATARM–09-Jul-09
25.5.2
Name:
RTC Mode Register
RTC_MR
Access Type:
Read/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
–
–
–
–
–
–
–
HRMOD
• HRMOD: 12-/24-hour Mode
0 = 24-hour mode is selected.
1 = 12-hour mode is selected.
All non-significant bits read zero.
310
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25.5.3
Name:
RTC Time Register
RTC_TIMR
Access Type:
Read/Write
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
AMPM
15
14
10
9
8
2
1
0
HOUR
13
12
–
7
11
MIN
6
5
–
4
3
SEC
• SEC: Current Second
The range that can be set is 0 - 59 (BCD).
The lowest four bits encode the units. The higher bits encode the tens.
• MIN: Current Minute
The range that can be set is 0 - 59 (BCD).
The lowest four bits encode the units. The higher bits encode the tens.
• HOUR: Current Hour
The range that can be set is 1 - 12 (BCD) in 12-hour mode or 0 - 23 (BCD) in 24-hour mode.
• AMPM: Ante Meridiem Post Meridiem Indicator
This bit is the AM/PM indicator in 12-hour mode.
0 = AM.
1 = PM.
All non-significant bits read zero.
311
1768I–ATARM–09-Jul-09
25.5.4
Name:
RTC Calendar Register
RTC_CALR
Access Type:
Read/Write
31
30
–
–
23
22
29
28
27
21
20
19
DAY
15
14
26
25
24
18
17
16
DATE
MONTH
13
12
11
10
9
8
3
2
1
0
YEAR
7
6
5
–
4
CENT
• CENT: Current Century
The range that can be set is 19 - 20 (BCD).
The lowest four bits encode the units. The higher bits encode the tens.
• YEAR: Current Year
The range that can be set is 00 - 99 (BCD).
The lowest four bits encode the units. The higher bits encode the tens.
• MONTH: Current Month
The range that can be set is 01 - 12 (BCD).
The lowest four bits encode the units. The higher bits encode the tens.
• DAY: Current Day
The range that can be set is 1 - 7 (BCD).
The coding of the number (which number represents which day) is user-defined as it has no effect on the date counter.
• DATE: Current Date
The range that can be set is 01 - 31 (BCD).
The lowest four bits encode the units. The higher bits encode the tens.
All non-significant bits read zero.
312
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25.5.5
Name:
RTC Time Alarm Register
RTC_TIMALR
Access Type:
Read/Write
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
21
20
19
18
17
16
10
9
8
2
1
0
23
22
HOUREN
AMPM
15
14
HOUR
13
12
MINEN
7
11
MIN
6
5
SECEN
4
3
SEC
• SEC: Second Alarm
This field is the alarm field corresponding to the BCD-coded second counter.
• SECEN: Second Alarm Enable
0 = The second-matching alarm is disabled.
1 = The second-matching alarm is enabled.
• MIN: Minute Alarm
This field is the alarm field corresponding to the BCD-coded minute counter.
• MINEN: Minute Alarm Enable
0 = The minute-matching alarm is disabled.
1 = The minute-matching alarm is enabled.
• HOUR: Hour Alarm
This field is the alarm field corresponding to the BCD-coded hour counter.
• AMPM: AM/PM Indicator
This field is the alarm field corresponding to the BCD-coded hour counter.
• HOUREN: Hour Alarm Enable
0 = The hour-matching alarm is disabled.
1 = The hour-matching alarm is enabled.
313
1768I–ATARM–09-Jul-09
25.5.6
Name:
RTC Calendar Alarm Register
RTC_CALALR
Access Type:
Read/Write
31
30
DATEEN
–
29
28
27
26
25
24
18
17
16
DATE
23
22
21
MTHEN
–
–
20
19
15
14
13
12
11
10
9
8
–
–
–
–
–
–
–
–
MONTH
7
6
5
4
3
2
1
0
–
–
–
–
–
–
–
–
• MONTH: Month Alarm
This field is the alarm field corresponding to the BCD-coded month counter.
• MTHEN: Month Alarm Enable
0 = The month-matching alarm is disabled.
1 = The month-matching alarm is enabled.
• DATE: Date Alarm
This field is the alarm field corresponding to the BCD-coded date counter.
• DATEEN: Date Alarm Enable
0 = The date-matching alarm is disabled.
1 = The date-matching alarm is enabled.
314
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AT91RM9200
25.5.7
Name:
RTC Status Register
RTC_SR
Access Type:
Read-only
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
–
–
–
CALEV
TIMEV
SEC
ALARM
ACKUPD
• ACKUPD: Acknowledge for Update
0 = Time and calendar registers cannot be updated.
1 = Time and calendar registers can be updated.
• ALARM: Alarm Flag
0 = No alarm matching condition occurred.
1 = An alarm matching condition has occurred.
• SEC: Second Event
0 = No second event has occurred since the last clear.
1 = At least one second event has occurred since the last clear.
• TIMEV: Time Event
0 = No time event has occurred since the last clear.
1 = At least one time event has occurred since the last clear.
The time event is selected in the TIMEVSEL field in RTC_CTRL (Control Register) and can be any one of the following
events: minute change, hour change, noon, midnight (day change).
• CALEV: Calendar Event
0 = No calendar event has occurred since the last clear.
1 = At least one calendar event has occurred since the last clear.
The calendar event is selected in the CALEVSEL field in RTC_CR and can be any one of the following events: week
change, month change and year change.
315
1768I–ATARM–09-Jul-09
25.5.8
Name:
RTC Status Clear Command Register
RTC_SCCR
Access Type:
Write-only
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
–
–
–
CALCLR
TIMCLR
SECCLR
ALRCLR
ACKCLR
• Status Flag Clear
0 = No effect.
1 = Clears corresponding status flag in the Status Register (RTC_SR).
316
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25.5.9
Name:
RTC Interrupt Enable Register
RTC_IER
Access Type:
Write-only
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
–
–
–
CALEN
TIMEN
SECEN
ALREN
ACKEN
• ACKEN: Acknowledge Update Interrupt Enable
0 = No effect.
1 = The acknowledge for update interrupt is enabled.
• ALREN: Alarm Interrupt Enable
0 = No effect.
1 = The alarm interrupt is enabled.
• SECEN: Second Event Interrupt Enable
0 = No effect.
1 = The second periodic interrupt is enabled.
• TIMEN: Time Event Interrupt Enable
0 = No effect.
1 = The selected time event interrupt is enabled.
• CALEN: Calendar Event Interrupt Enable
0 = No effect.
• 1 = The selected calendar event interrupt is enabled.
317
1768I–ATARM–09-Jul-09
25.5.10
Name:
RTC Interrupt Disable Register
RTC_IDR
Access Type:
Write-only
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
–
–
–
CALDIS
TIMDIS
SECDIS
ALRDIS
ACKDIS
• ACKDIS: Acknowledge Update Interrupt Disable
0 = No effect.
1 = The acknowledge for update interrupt is disabled.
• ALRDIS: Alarm Interrupt Disable
0 = No effect.
1 = The alarm interrupt is disabled.
• SECDIS: Second Event Interrupt Disable
0 = No effect.
1 = The second periodic interrupt is disabled.
• TIMDIS: Time Event Interrupt Disable
0 = No effect.
1 = The selected time event interrupt is disabled.
• CALDIS: Calendar Event Interrupt Disable
0 = No effect.
1 = The selected calendar event interrupt is disabled.
318
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
25.5.11
Name:
RTC Interrupt Mask Register
RTC_IMR
Access Type:
Read-only
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
–
–
–
CAL
TIM
SEC
ALR
ACK
• ACK: Acknowledge Update Interrupt Mask
0 = The acknowledge for update interrupt is disabled.
1 = The acknowledge for update interrupt is enabled.
• ALR: Alarm Interrupt Mask
0 = The alarm interrupt is disabled.
1 = The alarm interrupt is enabled.
• SEC: Second Event Interrupt Mask
0 = The second periodic interrupt is disabled.
1 = The second periodic interrupt is enabled.
• TIM: Time Event Interrupt Mask
0 = The selected time event interrupt is disabled.
1 = The selected time event interrupt is enabled.
• CAL: Calendar Event Interrupt Mask
0 = The selected calendar event interrupt is disabled.
1 = The selected calendar event interrupt is enabled.
319
1768I–ATARM–09-Jul-09
25.5.12
Name:
RTC Valid Entry Register
RTC_VER
Access Type:
Read-only
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
–
–
–
–
NVCALAR
NVTIMALR
NVCAL
NVTIM
• NVTIM: Non valid Time
0 = No invalid data has been detected in RTC_TIMR (Time Register).
1 = RTC_TIMR has contained invalid data since it was last programmed.
• NVCAL: Non valid Calendar
0 = No invalid data has been detected in RTC_CALR (Calendar Register).
1 = RTC_CALR has contained invalid data since it was last programmed.
• NVTIMALR: Non valid Time Alarm
0 = No invalid data has been detected in RTC_TIMALR (Time Alarm Register).
1 = RTC_TIMALR has contained invalid data since it was last programmed.
• NVCALALR: Non valid Calendar Alarm
0 = No invalid data has been detected in RTC_CALALR (Calendar Alarm Register).
1 = RTC_CALALR has contained invalid data since it was last programmed.
320
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AT91RM9200
26. Debug Unit (DBGU)
26.1
Overview
The Debug Unit provides a single entry point from the processor for access to all the debug
capabilities of Atmel’s ARM-based systems.
The Debug Unit features a two-pin UART that can be used for several debug and trace purposes
and offers an ideal medium for in-situ programming solutions and debug monitor communications. Moreover, the association with two Peripheral DMA Controller channels permits packet
handling for these tasks with processor time reduced to a minimum.
The Debug Unit also makes the Debug Communication Channel (DCC) signals provided by the
In-circuit Emulator of the ARM processor visible to the software. These signals indicate the status of the DCC read and write registers and generate an interrupt to the ARM processor, making
possible the handling of the DCC under interrupt control.
Chip Identifier registers permit recognition of the device and its revision. These registers inform
as to the sizes and types of the on-chip memories, as well as the set of embedded peripherals.
Finally, the Debug Unit features a Force NTRST capability that enables the software to decide
whether to prevent access to the system via the In-circuit Emulator. This permits protection of
the code, stored in ROM.
Important features of the Debug Unit are:
• System Peripheral to Facilitate Debug of Atmel’s ARM-based Systems
• Composed of Three Functions
– Two-pin UART
– Debug Communication Channel (DCC) Support
– Chip ID Registers
• Two-pin UART
– Implemented Features are 100% Compatible with the Standard Atmel USART
– Independent Receiver and Transmitter with a Common Programmable Baud Rate
Generator
– Even, Odd, Mark or Space Parity Generation
– Parity, Framing and Overrun Error Detection
– Automatic Echo, Local Loopback and Remote Loopback Channel Modes
– Interrupt Generation
– Support for Two Peripheral DMA Controller (PDC) Channels with Connection to
Receiver and Transmitter
• Debug Communication Channel Support
– Offers Visibility of COMMRX and COMMTX Signals from the ARM Processor
– Interrupt Generation
• Chip ID Registers
– Identification of the Device Revision, Sizes of the Embedded Memories, Set of
Peripherals
321
1768I–ATARM–09-Jul-09
26.2
Block Diagram
Figure 26-1. Debug Unit Functional Block Diagram
Peripheral
Bridge
Peripheral Data Controller
APB
Debug Unit
DTXD
Transmit
Power
Management
Controller
Parallel
Input/
Output
Baud Rate
Generator
MCK
Receive
DRXD
COMMRX
ARM
Processor
COMMTX
DCC
Handler
Chip ID
nTRST
ICE
Access
Handler
Interrupt
Control
NTRST(1)
DBGU Interupt
Force NTRST
Note:
Table 26-1.
Other
System
Interrupt
Sources
Source 1
Advanced
Interrupt
Controller
1. If NTRST pad is not bonded out, it is connected to NRST.
Debug Unit Pin Description
Pin Name
Description
Type
DRXD
Debug Receive Data
Input
DTXD
Debug Transmit Data
Output
Figure 26-2. Debug Unit Application Example
Boot Program
Debug Monitor
Trace Manager
Debug Unit
RS232 Drivers
Programming Tool
322
Debug Console
Trace Console
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
26.3
26.3.1
Product Dependencies
I/O Lines
Depending on product integration, the Debug Unit pins may be multiplexed with PIO lines. In this
case, the programmer must first configure the corresponding PIO Controller to enable I/O lines
operations of the Debug Unit.
26.3.2
Power Management
Depending on product integration, the Debug Unit clock may be controllable through the Power
Management Controller. In this case, the programmer must first configure the PMC to enable the
Debug Unit clock. Usually, the peripheral identifier used for this purpose is 1.
26.3.3
Interrupt Source
Depending on product integration, the Debug Unit interrupt line is connected to one of the interrupt sources of the Advanced Interrupt Controller. Interrupt handling requires programming of
the AIC before configuring the Debug Unit. Usually, the Debug Unit interrupt line connects to the
interrupt source 1 of the AIC, which may be shared with the real-time clock, the system timer
interrupt lines and other system peripheral interrupts, as shown in Figure 26-1. This sharing
requires the programmer to determine the source of the interrupt when the source 1 is triggered.
26.4
UART Operations
The Debug Unit operates as a UART, (asynchronous mode only) and supports only 8-bit character handling (with parity). It has no clock pin.
The Debug Unit's UART is made up of a receiver and a transmitter that operate independently,
and a common baud rate generator. Receiver timeout and transmitter time guard are not implemented. However, all the implemented features are compatible with those of a standard USART.
26.4.1
Baud Rate Generator
The baud rate generator provides the bit period clock named baud rate clock to both the receiver
and the transmitter.
The baud rate clock is the master clock divided by 16 times the value (CD) written in
DBGU_BRGR (Baud Rate Generator Register). If DBGU_BRGR is set to 0, the baud rate clock
is disabled and the Debug Unit's UART remains inactive. The maximum allowable baud rate is
Master Clock divided by 16. The minimum allowable baud rate is Master Clock divided by (16 x
65536).
MCK
Baud Rate = ---------------------16 × CD
323
1768I–ATARM–09-Jul-09
Figure 26-3. Baud Rate Generator
CD
CD
MCK
16-bit Counter
OUT
>1
1
0
Divide
by 16
Baud Rate
Clock
0
Receiver
Sampling Clock
26.4.2
26.4.2.1
Receiver
Receiver Reset, Enable and Disable
After device reset, the Debug Unit receiver is disabled and must be enabled before being used.
The receiver can be enabled by writing the control register DBGU_CR with the bit RXEN at 1. At
this command, the receiver starts looking for a start bit.
The programmer can disable the receiver by writing DBGU_CR with the bit RXDIS at 1. If the
receiver is waiting for a start bit, it is immediately stopped. However, if the receiver has already
detected a start bit and is receiving the data, it waits for the stop bit before actually stopping its
operation.
The programmer can also put the receiver in its reset state by writing DBGU_CR with the bit
RSTRX at 1. In doing so, the receiver immediately stops its current operations and is disabled,
whatever its current state. If RSTRX is applied when data is being processed, this data is lost.
26.4.2.2
Start Detection and Data Sampling
The Debug Unit only supports asynchronous operations, and this affects only its receiver. The
Debug Unit receiver detects the start of a received character by sampling the DRXD signal until
it detects a valid start bit. A low level (space) on DRXD is interpreted as a valid start bit if it is
detected for more than 7 cycles of the sampling clock, which is 16 times the baud rate. Hence, a
space that is longer than 7/16 of the bit period is detected as a valid start bit. A space which is
7/16 of a bit period or shorter is ignored and the receiver continues to wait for a valid start bit.
When a valid start bit has been detected, the receiver samples the DRXD at the theoretical midpoint of each bit. It is assumed that each bit lasts 16 cycles of the sampling clock (1-bit period)
so the bit sampling point is eight cycles (0.5-bit period) after the start of the bit. The first sampling
point is therefore 24 cycles (1.5-bit periods) after the falling edge of the start bit was detected.
Each subsequent bit is sampled 16 cycles (1-bit period) after the previous one.
324
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Figure 26-4. Start Bit Detection
Sampling Clock
DRXD
True Start
Detection
D0
Baud Rate
Clock
Figure 26-5. Character Reception
Example: 8-bit, parity enabled 1 stop
0.5 bit
period
1 bit
period
DRXD
D0
D1
True Start Detection
Sampling
26.4.2.3
D2
D3
D4
D5
D6
D7
Stop Bit
Parity Bit
Receiver Ready
When a complete character is received, it is transferred to the DBGU_RHR and the RXRDY status bit in DBGU_SR (Status Register) is set. The bit RXRDY is automatically cleared when the
receive holding register DBGU_RHR is read.
Figure 26-6. Receiver Ready
DRXD
S
D0
D1
D2
D3
D4
D5
D6
D7
S
P
D0
D1
D2
D3
D4
D5
D6
D7
P
RXRDY
Read DBGU_RHR
26.4.2.4
Receiver Overrun
If DBGU_RHR has not been read by the software (or the Peripheral DMA Controller) since the
last transfer, the RXRDY bit is still set and a new character is received, the OVRE status bit in
DBGU_SR is set. OVRE is cleared when the software writes the control register DBGU_CR with
the bit RSTSTA (Reset Status) at 1.
Figure 26-7. Receiver Overrun
DRXD
S
D0
D1
D2
D3
D4
D5
D6
D7
P
stop
S
D0
D1
D2
D3
D4
D5
D6
D7
P
stop
RXRDY
OVRE
RSTSTA
26.4.2.5
Parity Error
Each time a character is received, the receiver calculates the parity of the received data bits, in
accordance with the field PAR in DBGU_MR. It then compares the result with the received parity
325
1768I–ATARM–09-Jul-09
bit. If different, the parity error bit PARE in DBGU_SR is set at the same time the RXRDY is set.
The parity bit is cleared when the control register DBGU_CR is written with the bit RSTSTA
(Reset Status) at 1. If a new character is received before the reset status command is written,
the PARE bit remains at 1.
Figure 26-8. Parity Error
DRXD
S
D0
D1
D2
D3
D4
D5
D6
D7
P
stop
RXRDY
PARE
Wrong Parity Bit
26.4.2.6
RSTSTA
Receiver Framing Error
When a start bit is detected, it generates a character reception when all the data bits have been
sampled. The stop bit is also sampled and when it is detected at 0, the FRAME (Framing Error)
bit in DBGU_SR is set at the same time the RXRDY bit is set. The bit FRAME remains high until
the control register DBGU_CR is written with the bit RSTSTA at 1.
Figure 26-9. Receiver Framing Error
DRXD
S
D0
D1
D2
D3
D4
D5
D6
D7
P
stop
RXRDY
FRAME
Stop Bit
Detected at 0
26.4.3
26.4.3.1
RSTSTA
Transmitter
Transmitter Reset, Enable and Disable
After device reset, the Debug Unit transmitter is disabled and it must be enabled before being
used. The transmitter is enabled by writing the control register DBGU_CR with the bit TXEN at 1.
From this command, the transmitter waits for a character to be written in the Transmit Holding
Register DBGU_THR before actually starting the transmission.
The programmer can disable the transmitter by writing DBGU_CR with the bit TXDIS at 1. If the
transmitter is not operating, it is immediately stopped. However, if a character is being processed into the Shift Register and/or a character has been written in the Transmit Holding
Register, the characters are completed before the transmitter is actually stopped.
The programmer can also put the transmitter in its reset state by writing the DBGU_CR with the
bit RSTTX at 1. This immediately stops the transmitter, whether or not it is processing
characters.
26.4.3.2
326
Transmit Format
The Debug Unit transmitter drives the pin DTXD at the baud rate clock speed. The line is driven
depending on the format defined in the Mode Register and the data stored in the Shift Register.
One start bit at level 0, then the 8 data bits, from the lowest to the highest bit, one optional parity
bit and one stop bit at 1 are consecutively shifted out as shown on the following figure. The field
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
PARE in the mode register DBGU_MR defines whether or not a parity bit is shifted out. When a
parity bit is enabled, it can be selected between an odd parity, an even parity, or a fixed space or
mark bit.
Figure 26-10. Character Transmission
Example: Parity enabled
Baud Rate
Clock
DTXD
Start
Bit
26.4.3.3
D0
D1
D2
D3
D4
D5
D6
D7
Parity
Bit
Stop
Bit
Transmitter Control
When the transmitter is enabled, the bit TXRDY (Transmitter Ready) is set in the status register
DBGU_SR. The transmission starts when the programmer writes in the Transmit Holding Register DBGU_THR, and after the written character is transferred from DBGU_THR to the Shift
Register. The bit TXRDY remains high until a second character is written in DBGU_THR. As
soon as the first character is completed, the last character written in DBGU_THR is transferred
into the shift register and TXRDY rises again, showing that the holding register is empty.
When both the Shift Register and the DBGU_THR are empty, i.e., all the characters written in
DBGU_THR have been processed, the bit TXEMPTY rises after the last stop bit has been
completed.
Figure 26-11. Transmitter Control
DBGU_THR
Data 0
Data 1
Shift Register
DTXD
Data 0
S
Data 0
Data 1
P
stop
S
Data 1
P
stop
TXRDY
TXEMPTY
Write Data 0
in DBGU_THR
26.4.4
Write Data 1
in DBGU_THR
Peripheral DMA Controller
Both the receiver and the transmitter of the Debug Unit's UART are generally connected to a
Peripheral DMA Controller (PDC) channel.
The Peripheral DMA controller channels are programmed via registers that are mapped within
the Debug Unit user interface from the offset 0x100. The status bits are reported in the Debug
Unit status register DBGU_SR and can generate an interrupt.
327
1768I–ATARM–09-Jul-09
The RXRDY bit triggers the PDC channel data transfer of the receiver. This results in a read of
the data in DBGU_RHR. The TXRDY bit triggers the PDC channel data transfer of the transmitter. This results in a write of a data in DBGU_THR.
26.4.5
Test Modes
The Debug Unit supports three tests modes. These modes of operation are programmed by
using the field CHMODE (Channel Mode) in the mode register DBGU_MR.
The Automatic Echo mode allows bit-by-bit retransmission. When a bit is received on the DRXD
line, it is sent to the DTXD line. The transmitter operates normally, but has no effect on the
DTXD line.
The Local Loopback mode allows the transmitted characters to be received. DTXD and DRXD
pins are not used and the output of the transmitter is internally connected to the input of the
receiver. The DRXD pin level has no effect and the DTXD line is held high, as in idle state.
The Remote Loopback mode directly connects the DRXD pin to the DTXD line. The transmitter
and the receiver are disabled and have no effect. This mode allows a bit-by-bit retransmission.
Figure 26-12. Test Modes
Automatic Echo
RXD
Receiver
Transmitter
Disabled
TXD
Local Loopback
Disabled
Receiver
RXD
VDD
Disabled
Transmitter
Remote Loopback
Receiver
Transmitter
26.4.6
328
TXD
VDD
Disabled
Disabled
RXD
TXD
Debug Communication Channel Support
The Debug Unit handles the signals COMMRX and COMMTX that come from the Debug Communication Channel of the ARM Processor and are driven by the In-circuit Emulator.
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
The Debug Communication Channel contains two registers that are accessible through the ICE
Breaker on the JTAG side and through the coprocessor 0 on the ARM Processor side.
As a reminder, the following instructions are used to read and write the Debug Communication
Channel:
MRC
p14, 0, Rd, c1, c0, 0
Returns the debug communication data read register into Rd
MCR
p14, 0, Rd, c1, c0, 0
Writes the value in Rd to the debug communication data write register.
The bits COMMRX and COMMTX, which indicate, respectively, that the read register has been
written by the debugger but not yet read by the processor, and that the write register has been
written by the processor and not yet read by the debugger, are wired on the two highest bits of
the status register DBGU_SR. These bits can generate an interrupt. This feature permits handling under interrupt a debug link between a debug monitor running on the target system and a
debugger.
26.4.7
Chip Identifier
The Debug Unit features two chip identifier registers, DBGU_CIDR (Chip ID Register) and
DBGU_EXID (Extension ID). Both registers contain a hard-wired value that is read-only. The first
register contains the following fields:
• EXT - shows the use of the extension identifier register
• NVPTYP and NVPSIZ - identifies the type of embedded non-volatile memory and its size
• ARCH - identifies the set of embedded peripheral
• SRAMSIZ - indicates the size of the embedded SRAM
• EPROC - indicates the embedded ARM processor
• VERSION - gives the revision of the silicon
The second register is device-dependent and reads 0 if the bit EXT is 0.
329
1768I–ATARM–09-Jul-09
26.5
Debug Unit User Interface
Table 26-2.
Debug Unit Memory Map
Offset
Register
Name
Access
Reset Value
0x0000
Control Register
DBGU_CR
Write-only
–
0x0004
Mode Register
DBGU_MR
Read/Write
0x0
0x0008
Interrupt Enable Register
DBGU_IER
Write-only
–
0x000C
Interrupt Disable Register
DBGU_IDR
Write-only
–
0x0010
Interrupt Mask Register
DBGU_IMR
Read-only
0x0
0x0014
Status Register
DBGU_SR
Read-only
–
0x0018
Receive Holding Register
DBGU_RHR
Read-only
0x0
0x001C
Transmit Holding Register
DBGU_THR
Write-only
–
0x0020
Baud Rate Generator Register
DBGU_BRGR
Read/Write
0x0
–
–
–
0x0024 - 0x003C
Reserved
0X0040
Chip ID Register
DBGU_CIDR
Read-only
–
0X0044
Chip ID Extension Register
DBGU_EXID
Read-only
–
Reserved
0x004C - 0x00FC
Reserved
–
–
–
0x0100 - 0x0124
PDC Area
–
–
–
330
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1768I–ATARM–09-Jul-09
AT91RM9200
26.5.1
Name:
Debug Unit Control Register
DBGU_CR
Access Type:
Write-only
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
–
–
–
–
RSTSTA
7
6
5
4
3
2
1
0
TXDIS
TXEN
RXDIS
RXEN
RSTTX
RSTRX
–
–
• RSTRX: Reset Receiver
0 = No effect.
1 = The receiver logic is reset and disabled. If a character is being received, the reception is aborted.
• RSTTX: Reset Transmitter
0 = No effect.
1 = The transmitter logic is reset and disabled. If a character is being transmitted, the transmission is aborted.
• RXEN: Receiver Enable
0 = No effect.
1 = The receiver is enabled if RXDIS is 0.
• RXDIS: Receiver Disable
0 = No effect.
1 = The receiver is disabled. If a character is being processed and RSTRX is not set, the character is completed before the
receiver is stopped.
• TXEN: Transmitter Enable
0 = No effect.
1 = The transmitter is enabled if TXDIS is 0.
• TXDIS: Transmitter Disable
0 = No effect.
1 = The transmitter is disabled. If a character is being processed and a character has been written the DBGU_THR and
RSTTX is not set, both characters are completed before the transmitter is stopped.
• RSTSTA: Reset Status Bits
0 = No effect.
1 = Resets the status bits PARE, FRAME and OVRE in the DBGU_SR.
331
1768I–ATARM–09-Jul-09
26.5.2
Name:
Debug Unit Mode Register
DBGU_MR
Access Type:
Read/Write
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
14
13
12
11
10
9
–
–
15
CHMODE
8
–
PAR
7
6
5
4
3
2
1
0
–
–
–
–
–
–
–
–
• PAR: Parity Type
PAR
Parity Type
0
0
0
Even parity
0
0
1
Odd parity
0
1
0
Space: parity forced to 0
0
1
1
Mark: parity forced to 1
1
x
x
No parity
• CHMODE: Channel Mode
CHMODE
332
Mode Description
0
0
Normal Mode
0
1
Automatic Echo
1
0
Local Loopback
1
1
Remote Loopback
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
26.5.3
Name:
Debug Unit Interrupt Enable Register
DBGU_IER
Access Type:
Write-only
31
30
29
28
27
26
25
24
COMMRX
COMMTX
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
RXBUFF
TXBUFE
–
TXEMPTY
–
7
6
5
4
3
2
1
0
PARE
FRAME
OVRE
ENDTX
ENDRX
–
TXRDY
RXRDY
• RXRDY: Enable RXRDY Interrupt
• TXRDY: Enable TXRDY Interrupt
• ENDRX: Enable End of Receive Transfer Interrupt
• ENDTX: Enable End of Transmit Interrupt
• OVRE: Enable Overrun Error Interrupt
• FRAME: Enable Framing Error Interrupt
• PARE: Enable Parity Error Interrupt
• TXEMPTY: Enable TXEMPTY Interrupt
• TXBUFE: Enable Buffer Empty Interrupt
• RXBUFF: Enable Buffer Full Interrupt
• COMMTX: Enable COMMTX (from ARM) Interrupt
• COMMRX: Enable COMMRX (from ARM) Interrupt
0 = No effect.
1 = Enables the corresponding interrupt.
333
1768I–ATARM–09-Jul-09
26.5.4
Name:
Debug Unit Interrupt Disable Register
DBGU_IDR
Access Type:
Write-only
31
30
29
28
27
26
25
24
COMMRX
COMMTX
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
RXBUFF
TXBUFE
–
TXEMPTY
–
7
6
5
4
3
2
1
0
PARE
FRAME
OVRE
ENDTX
ENDRX
–
TXRDY
RXRDY
• RXRDY: Disable RXRDY Interrupt
• TXRDY: Disable TXRDY Interrupt
• ENDRX: Disable End of Receive Transfer Interrupt
• ENDTX: Disable End of Transmit Interrupt
• OVRE: Disable Overrun Error Interrupt
• FRAME: Disable Framing Error Interrupt
• PARE: Disable Parity Error Interrupt
• TXEMPTY: Disable TXEMPTY Interrupt
• TXBUFE: Disable Buffer Empty Interrupt
• RXBUFF: Disable Buffer Full Interrupt
• COMMTX: Disable COMMTX (from ARM) Interrupt
• COMMRX: Disable COMMRX (from ARM) Interrupt
0 = No effect.
1 = Disables the corresponding interrupt.
334
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1768I–ATARM–09-Jul-09
AT91RM9200
26.5.5
Name:
Debug Unit Interrupt Mask Register
DBGU_IMR
Access Type:
Read-only
31
30
29
28
27
26
25
24
COMMRX
COMMTX
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
RXBUFF
TXBUFE
–
TXEMPTY
–
7
6
5
4
3
2
1
0
PARE
FRAME
OVRE
ENDTX
ENDRX
–
TXRDY
RXRDY
• RXRDY: Mask RXRDY Interrupt
• TXRDY: Disable TXRDY Interrupt
• ENDRX: Mask End of Receive Transfer Interrupt
• ENDTX: Mask End of Transmit Interrupt
• OVRE: Mask Overrun Error Interrupt
• FRAME: Mask Framing Error Interrupt
• PARE: Mask Parity Error Interrupt
• TXEMPTY: Mask TXEMPTY Interrupt
• TXBUFE: Mask TXBUFE Interrupt
• RXBUFF: Mask RXBUFF Interrupt
• COMMTX: Mask COMMTX Interrupt
• COMMRX: Mask COMMRX Interrupt
0 = The corresponding interrupt is disabled.
1 = The corresponding interrupt is enabled.
335
1768I–ATARM–09-Jul-09
26.5.6
Name:
Debug Unit Status Register
DBGU_SR
Access Type:
Read-only
31
30
29
28
27
26
25
24
COMMRX
COMMTX
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
RXBUFF
TXBUFE
–
TXEMPTY
–
7
6
5
4
3
2
1
0
PARE
FRAME
OVRE
ENDTX
ENDRX
–
TXRDY
RXRDY
• RXRDY: Receiver Ready
0 = No character has been received since the last read of the DBGU_RHR or the receiver is disabled.
1 = At least one complete character has been received, transferred to DBGU_RHR and not yet read.
• TXRDY: Transmitter Ready
0 = A character has been written to DBGU_THR and not yet transferred to the Shift Register, or the transmitter is disabled.
1 = There is no character written to DBGU_THR not yet transferred to the Shift Register.
• ENDRX: End of Receiver Transfer
0 = The End of Transfer signal from the receiver Peripheral DMA Controller channel is inactive.
1 = The End of Transfer signal from the receiver Peripheral DMA Controller channel is active.
• ENDTX: End of Transmitter Transfer
0 = The End of Transfer signal from the transmitter Peripheral DMA Controller channel is inactive.
1 = The End of Transfer signal from the transmitter Peripheral DMA Controller channel is active.
• 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.
• FRAME: Framing Error
0 = No framing error has occurred since the last RSTSTA.
1 = At least one framing error has occurred since the last RSTSTA.
• PARE: Parity Error
0 = No parity error has occurred since the last RSTSTA.
1 = At least one parity error has occurred since the last RSTSTA.
• TXEMPTY: Transmitter Empty
0 = There are characters in DBGU_THR, or characters being processed by the transmitter, or the transmitter is disabled.
1 = There are no characters in DBGU_THR and there are no characters being processed by the transmitter.
• TXBUFE: Transmission Buffer Empty
0 = The buffer empty signal from the transmitter PDC channel is inactive.
336
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
1 = The buffer empty signal from the transmitter PDC channel is active.
• RXBUFF: Receive Buffer Full
0 = The buffer full signal from the receiver PDC channel is inactive.
1 = The buffer full signal from the receiver PDC channel is active.
• COMMTX: Debug Communication Channel Write Status
0 = COMMTX from the ARM processor is inactive.
1 = COMMTX from the ARM processor is active.
• COMMRX: Debug Communication Channel Read Status
0 = COMMRX from the ARM processor is inactive.
1 = COMMRX from the ARM processor is active.
337
1768I–ATARM–09-Jul-09
26.5.7
Name:
Debug Unit Receiver Holding Register
DBGU_RHR
Access Type:
Read-only
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
RXCHR
• RXCHR: Received Character
Last received character if RXRDY is set.
338
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Debug Unit Transmit Holding Register
Name:
DBGU_THR
Access Type:
Write-only
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
TXCHR
• TXCHR: Character to be Transmitted
Next character to be transmitted after the current character if TXRDY is not set.
339
1768I–ATARM–09-Jul-09
26.5.8
Name:
Debug Unit Baud Rate Generator Register
DBGU_BRGR
Access Type:
Read/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
3
2
1
0
CD
7
6
5
4
CD
• CD: Clock Divisor
CD
0
Disabled
1
MCK
2 to 65535
340
Baud Rate Clock
MCK / (CD x 16)
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
26.5.9
Name:
Debug Unit Chip ID Register
DBGU_CIDR
Access Type:
31
Read-only
30
29
EXT
23
28
27
26
NVPTYP
22
21
20
19
18
ARCH
24
17
16
9
8
1
0
SRAMSIZ
15
14
13
12
0
0
0
0
6
5
4
7
25
ARCH
11
10
NVPSIZ
3
EPROC
2
VERSION
• VERSION: Version of the device
• EPROC: Embedded Processor
EPROC
Processor
0
0
1
ARM946ES™
0
1
0
ARM7TDMI®
1
0
0
ARM920T
• NVPSIZ: Nonvolatile Program Memory Size
NVPSIZ
Size
0
0
0
0
None
0
0
0
1
8K bytes
0
0
1
0
16K bytes
0
0
1
1
32K bytes
0
1
0
0
Reserved
0
1
0
1
64K bytes
0
1
1
0
Reserved
0
1
1
1
128K bytes
1
0
0
0
Reserved
1
0
0
1
256K bytes
1
0
1
0
Reserved
1
0
1
1
Reserved
1
1
0
0
Reserved
1
1
0
1
Reserved
1
1
1
0
Reserved
1
1
1
1
Reserved
341
1768I–ATARM–09-Jul-09
• SRAMSIZ: Internal SRAM Size
SRAMSIZ
Size
0
0
0
0
Reserved
0
0
0
1
1K bytes
0
0
1
0
2K bytes
0
0
1
1
Reserved
0
1
0
0
112K bytes
0
1
0
1
4K bytes
0
1
1
0
80K bytes
0
1
1
1
160K bytes
1
0
0
0
8K bytes
1
0
0
1
16K bytes
1
0
1
0
32K bytes
1
0
1
1
64K bytes
1
1
0
0
128K bytes
1
1
0
1
256K bytes
1
1
1
0
96K bytes
1
1
1
1
512K bytes
• ARCH: Architecture Identifier
ARCH
Hex
Dec
Architecture
0x40
0100 0000
AT91x40 Series
0x63
0110 0011
AT91x63 Series
0x55
0101 0101
AT91x55 Series
0x42
0100 0010
AT91x42 Series
0x92
1001 0010
AT91x92 Series
0x34
0011 0100
AT91x34 Series
• NVPTYP: Nonvolatile Program Memory Type
NVPTYP
Memory
0
0
0
ROM
0
0
1
ROMless or on-chip Flash
1
0
0
SRAM emulating ROM
• EXT: Extension Flag
0 = Chip ID has a single register definition without extension
1 = An extended Chip ID exists.
342
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
26.5.10
Name:
Debug Unit Chip ID Extension Register
DBGU_EXID
Access Type:
31
Read-only
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
EXID
23
22
21
20
EXID
15
14
13
12
EXID
7
6
5
4
EXID
• EXID: Chip ID Extension
Reads 0 if the bit EXT in DBGU_CIDR is 0.
343
1768I–ATARM–09-Jul-09
344
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
27. Parallel Input/Output Controller (PIO)
27.1
Overview
The Parallel Input/Output Controller (PIO) manages up to 32 fully programmable input/output
lines. 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.
Each I/O line is associated with a bit number in all of the 32-bit registers of the 32-bit wide User
Interface.
Each I/O line of the PIO Controller features:
• An input change interrupt enabling level change on any I/O line.
• A glitch filter providing rejection of pulses lower than one-half of clock cycle.
• Multi-drive capability similar to an open drain I/O line.
• Control of the pull-up of the I/O line.
• Input visibility and output control.
The PIO Controller also features a synchronous output providing up to 32 bits of data output in a
single write operation.
Important features of the PIO also include:
• Up to 32 Programmable I/O Lines
• Fully Programmable through Set/Clear Registers
• Multiplexing of Two Peripheral Functions per I/O Line
• For each I/O Line (Whether Assigned to a Peripheral or Used as General Purpose I/O)
– Input Change Interrupt
– Glitch Filter
– Multi-drive Option Enables Driving in Open Drain
– Programmable Pull-up on Each I/O Line
– Pin Data Status Register, Supplies Visibility of the Level on the Pin at Any Time
• Synchronous Output, Provides Set and Clear of Several I/O lines in a Single Write
345
1768I–ATARM–09-Jul-09
27.2
Block Diagram
Figure 27-1. Block Diagram
PIO Controller
AIC
PIO Interrupt
PMC
PIO Clock
Embedded
Peripheral
Embedded
Peripheral
Embedded
Peripheral
Up to 32
peripheral IOs
PIN
Embedded
Peripheral
Embedded
Peripheral
Embedded
Peripheral
Up to 32 pins
PIN
Up to 32
peripheral IOs
PIN
APB
Figure 27-2. Application Block Diagram
On-chip Peripheral Drivers
Keyboard Driver
Control & Command
Driver
On-chip Peripherals
PIO Controller
Keyboard Driver
346
General Purpose I/Os
External Devices
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
27.3
Product Dependencies
27.3.1
Pin Multiplexing
Each pin is configurable, according to product definition as either a general-purpose I/O line
only, or as an I/O line multiplexed with one or two peripheral I/Os. As the multiplexing is hardware-defined and thus product-dependent, the hardware designer and programmer must
carefully determine the configuration of the PIO controllers required by their application. When
an I/O line is general-purpose only, i.e. not multiplexed with any peripheral I/O, programming of
the PIO Controller regarding the assignment to a peripheral has no effect and only the PIO Controller can control how the pin is driven by the product.
27.3.2
External Interrupt Lines
The interrupt signals FIQ and IRQ0 to IRQn are most generally multiplexed through the PIO
Controllers. However, it is not necessary to assign the I/O line to the interrupt function as the
PIO Controller has no effect on inputs and the interrupt lines (FIQ or IRQs) are used only as
inputs.
27.3.3
Power Management
The Power Management Controller controls the PIO Controller clock in order to save power.
Writing any of the registers of the user interface does not require the PIO Controller clock to be
enabled. This means that the configuration of the I/O lines does not require the PIO Controller
clock to be enabled.
However, when the clock is disabled, not all of the features of the PIO Controller are available.
Note that the Input Change Interrupt and the read of the pin level require the clock to be
validated.
After a hardware reset, the PIO clock is disabled by default (see Power Management Controller).
The user must configure the Power Management Controller before any access to the input line
information.
27.3.4
Interrupt Generation
For interrupt handling, the PIO Controllers are considered as user peripherals. This means that
the PIO Controller interrupt lines are connected among the interrupt sources 2 to 31. Refer to the
PIO Controller peripheral identifier in the product description to identify the interrupt sources
dedicated to the PIO Controllers.
The PIO Controller interrupt can be generated only if the PIO Controller clock is enabled.
27.4
Functional Description
The PIO Controller features up to 32 fully-programmable I/O lines. Most of the control logic associated to each I/O is represented in Figure 27-3.
347
1768I–ATARM–09-Jul-09
Figure 27-3. I/O Line Control Logic
PIO_OER
PIO_OSR
PIO_PUER
PIO_ODR
PIO_PUSR
PIO_PUDR
1
Peripheral A
Output Enable
0
0
Peripheral B
Output Enable
0
1
PIO_PER
PIO_ASR
PIO_PDR
PIO_BSR
Peripheral A
Output
1
PIO_PSR
PIO_ABSR
PIO_MDER
0
PIO_MDSR
PIO_MDDR
0
Peripheral B
Output
1
PIO_SODR
1
PIO_ODSR
1
Pad
PIO_CODR
0
Peripheral A
Input
PIO_PDSR
Peripheral B
Input
PIO_ISR
0
Edge
Detector
Glitch
Filter
1
1
0
PIO Interrupt
PIO_IFER
PIO_IFSR
PIO_IFDR
PIO_IER
PIO_IMR
PIO_IDR
27.4.1
Pull-up Resistor Control
Each I/O line is designed with an embedded pull-up resistor. The internal pull-ups have a typical
value of 200 kOhm (see the product electrical characteristics for more details about this value).
The pull-up resistor can be enabled or disabled by writing respectively PIO_PUER (Pull-up
Enable Register) and PIO_PUDR (Pull-up Disable Resistor). Writing in these registers results in
setting or clearing the corresponding bit in PIO_PUSR (Pull-up Status Register). Reading a 1 in
PIO_PUSR means the pull-up is disabled and reading a 0 means the pull-up is enabled.
Control of the pull-up resistor is possible regardless of the configuration of the I/O line.
348
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
After reset, all of the pull-ups are enabled, i.e. PIO_PUSR resets at the value 0x0.
27.4.2
I/O Line or Peripheral Function Selection
When a pin is multiplexed with one or two peripheral functions, the selection is controlled with
the registers PIO_PER (PIO Enable Register) and PIO_PDR (PIO Disable Register). The register PIO_PSR (PIO Status Register) is the result of the set and clear registers and indicates
whether the pin is controlled by the corresponding peripheral or by the PIO Controller. A value of
0 indicates that the pin is controlled by the corresponding on-chip peripheral selected in the
PIO_ABSR (AB Select Status Register). A value of 1 indicates the pin is controlled by the PIO
controller.
If a pin is used as a general purpose I/O line (not multiplexed with an on-chip peripheral),
PIO_PER and PIO_PDR have no effect and PIO_PSR returns 1 for the corresponding bit.
After reset, most generally, the I/O lines are controlled by the PIO controller, i.e. PIO_PSR
resets at 1. However, in some events, it is important that PIO lines are controlled by the peripheral (as in the case of memory chip select lines that must be driven inactive after reset or for
address lines that must be driven low for booting out of an external memory). Thus, the reset
value of PIO_PSR is defined at the product level, depending on the multiplexing of the device.
27.4.3
Peripheral A or B Selection
The PIO Controller provides multiplexing of up to two peripheral functions on a single pin. The
selection is performed by writing PIO_ASR (A Select Register) and PIO_BSR (Select B Register). PIO_ABSR (AB Select Status Register) indicates which peripheral line is currently selected.
For each pin, the corresponding bit at level 0 means peripheral A is selected whereas the corresponding bit at level 1 indicates that peripheral B is selected.
Note that multiplexing of peripheral lines A and B only affects the output line. The peripheral
input lines are always connected to the pin input.
After reset, PIO_ABSR is 0, thus indicating that all the PIO lines are configured on peripheral A.
However, peripheral A generally does not drive the pin as the PIO Controller resets in I/O line
mode.
Writing in PIO_ASR and PIO_BSR manages PIO_ABSR regardless of the configuration of the
pin. However, assignment of a pin to a peripheral function requires a write in the corresponding
peripheral selection register (PIO_ASR or PIO_BSR) in addition to a write in PIO_PDR.
27.4.4
Output Control
When the I/0 line is assigned to a peripheral function, i.e. the corresponding bit in PIO_PSR is at
0, the drive of the I/O line is controlled by the peripheral. Peripheral A or B, depending on the
value in PIO_ABSR, determines whether the pin is driven or not.
When the I/O line is controlled by the PIO controller, the pin can be configured to be driven. This
is done by writing PIO_OER (Output Enable Register) and PIO_PDR (Output Disable Register).
The results of these write operations are detected in PIO_OSR (Output Status Register). When
a bit in this register is at 0, the corresponding I/O line is used as an input only. When the bit is at
1, the corresponding I/O line is driven by the PIO controller.
The level driven on an I/O line can be determined by writing in PIO_SODR (Set Output Data
Register) and PIO_CODR (Clear Output Data Register). These write operations respectively set
and clear PIO_ODSR (Output Data Status Register), which represents the data driven on the I/O
lines. Writing in PIO_OER and PIO_ODR manages PIO_OSR whether the pin is configured to
349
1768I–ATARM–09-Jul-09
be controlled by the PIO controller or assigned to a peripheral function. This enables configuration of the I/O line prior to setting it to be managed by the PIO Controller.
Similarly, writing in PIO_SODR and PIO_CODR effects PIO_ODSR. This is important as it
defines the first level driven on the I/O line.
27.4.5
Synchronous Data Output
Using the write operations in PIO_SODR and PIO_CODR can require that several instructions
be executed in order to define values on several bits. Both clearing and setting I/O lines on an 8bit port, for example, cannot be done at the same time, and thus might limit the application covered by the PIO Controller.
To avoid these inconveniences, the PIO Controller features a Synchronous Data Output to clear
and set a number of I/O lines in a single write. This is performed by authorizing the writing of
PIO_ODSR (Output Data Status Register) from the register set PIO_OWER (Output Write
Enable Register), PIO_OWDR (Output Write Disable Register) and PIO_OWSR (Output Write
Status Register). The value of PIO_OWSR register is user-definable by writing in PIO_OWER
and PIO_OWDR. It is used by the PIO Controller as a PIO_ODSR write authorization mask.
Authorizing the write of PIO_ODSR on a user-definable number of bits is especially useful, as it
guarantees that the unauthorized bit will not be changed when writing it and thus avoids the
need of a time consuming read-modify-write operation.
After reset, the synchronous data output is disabled on all the I/O lines as PIO_OWSR resets at
0x0.
27.4.6
Multi Drive Control (Open Drain)
Each I/O can be independently programmed in Open Drain by using the Multi Drive feature. This
feature permits several drivers to be connected on the I/O line which is driven low only by each
device. An external pull-up resistor (or enabling of the internal one) is generally required to guarantee a high level on the line.
The Multi Drive feature is controlled by PIO_MDER (Multi-driver Enable Register) and
PIO_MDDR (Multi-driver Disable Register). The Multi Drive can be selected whether the I/O line
is controlled by the PIO controller or assigned to a peripheral function. PIO_MDSR (Multi-driver
Status Register) indicates the pins that are configured to support external drivers.
After reset, the Multi Drive feature is disabled on all pins, i.e. PIO_MDSR resets at value 0x0.
27.4.7
350
Output Line Timings
Figure 27-4 shows how the outputs are driven either by writing PIO_SODR or PIO_CODR, or by
directly writing PIO_ODSR. This last case is valid only if the corresponding bit in PIO_OWSR is
set. Figure 27-4 also shows when the feedback in PIO_PDSR is available.
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Figure 27-4. Output Line Timings
MCK
Write PIO_SODR
Write PIO_ODSR at 1
APB Access
Write PIO_CODR
Write PIO_ODSR at 0
APB Access
PIO_ODSR
2 Cycles
2 Cycles
PIO_PDSR
27.4.8
Inputs
The level on each I/O line can be read through PIO_PDSR (Pin Data Status Register). This register indicates the level of the I/O lines regardless of their configuration, whether uniquely as an
input or driven by the PIO controller or driven by a peripheral.
Reading the I/O line levels requires the clock of the PIO controller to be enabled, otherwise
PIO_PDSR reads the levels present on the I/O line at the time the clock was disabled.
27.4.9
Input Glitch Filtering
Optional input glitch filters are independently programmable on each I/O line. When the glitch filter is enabled, a glitch with a duration of less than 1/2 Master Clock (MCK) cycle is automatically
rejected, while a pulse with a duration of 1 Master Clock cycle or more is accepted. For pulse
durations between 1/2 Master Clock cycle and 1 Master Clock cycle the pulse may or may not
be taken into account, depending on the precise timing of its occurrence. Thus for a pulse to be
visible it must exceed 1 Master Clock cycle, whereas for a glitch to be reliably filtered out, its
duration must not exceed 1/2 Master Clock cycle. The filter introduces one Master Clock cycle
latency if the pin level change occurs before a rising edge. However, this latency does not
appear if the pin level change occurs before a falling edge. This is illustrated in Figure 27-5.
The glitch filters are controlled by the register set; PIO_IFER (Input Filter Enable Register),
PIO_IFDR (Input Filter Disable Register) and PIO_IFSR (Input Filter Status Register). Writing
PIO_IFER and PIO_IFDR respectively sets and clears bits in PIO_IFSR. This last register
enables the glitch filter on the I/O lines.
When the glitch filter is enabled, it does not modify the behavior of the inputs on the peripherals.
It acts only on the value read in PIO_PDSR and on the input change interrupt detection. The
glitch filters require that the PIO Controller clock is enabled.
Figure 27-5. Input Glitch Filter Timing
MCK
Pin Level
1 cycle
1 cycle
1 cycle
1 cycle
PIO_PDSR
if PIO_IFSR = 0
2 cycles
1 cycle
PIO_PDSR
if PIO_IFSR = 1
351
1768I–ATARM–09-Jul-09
27.4.10
Input Change Interrupt
The PIO Controller can be programmed to generate an interrupt when it detects an input change
on an I/O line. The Input Change Interrupt is controlled by writing PIO_IER (Interrupt Enable
Register) and PIO_IDR (Interrupt Disable Register), which respectively enable and disable the
input change interrupt by setting and clearing the corresponding bit in PIO_IMR (Interrupt Mask
Register). As Input change detection is possible only by comparing two successive samplings of
the input of the I/O line, the PIO Controller clock must be enabled. The Input Change Interrupt is
available, regardless of the configuration of the I/O line, i.e. configured as an input only, controlled by the PIO Controller or assigned to a peripheral function.
When an input change is detected on an I/O line, the corresponding bit in PIO_ISR (Interrupt
Status Register) is set. If the corresponding bit in PIO_IMR is set, the PIO Controller interrupt
line is asserted. The interrupt signals of the thirty-two channels are ORed-wired together to generate a single interrupt signal to the Advanced Interrupt Controller.
When the software reads PIO_ISR, all the interrupts are automatically cleared. This signifies that
all the interrupts that are pending when PIO_ISR is read must be handled.
Figure 27-6. Input Change Interrupt Timings
MCK
PIO_PDSR
PIO_ISR
APB Access
Read PIO_ISR
27.5
APB Access
I/O Lines Programming Example
The programing example shown in Table 27-1 below is used to define the following
configuration.
• 4-bit output port on I/O lines 0 to 3, (should be written in a single write operation), open-drain,
with pull-up resistor
• Four output signals on I/O lines 4 to 7 (to drive LEDs for example), driven high and low, no
pull-up resistor
• Four input signals on I/O lines 8 to 11 (to read push-button states for example), with pull-up
resistors, glitch filters and input change interrupts
• Four input signals on I/O line 12 to 15 to read an external device status (polled, thus no input
change interrupt), no pull-up resistor, no glitch filter
• I/O lines 16 to 19 assigned to peripheral A functions with pull-up resistor
• I/O lines 20 to 23 assigned to peripheral B functions, no pull-up resistor
• I/O lines 24 to 27 assigned to peripheral A with Input Change Interrupt and pull-up resistor
Table 27-1.
352
Programming Example
Register
Value to be Written
PIO_PER
0x0000 FFFF
PIO_PDR
0x0FFF 0000
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table 27-1.
Programming Example
PIO_OER
0x0000 00FF
PIO_ODR
0x0FFF FF00
PIO_IFER
0x0000 0F00
PIO_IFDR
0x0FFF F0FF
PIO_SODR
0x0000 0000
PIO_CODR
0x0FFF FFFF
PIO_IER
0x0F00 0F00
PIO_IDR
0x00FF F0FF
PIO_MDER
0x0000 000F
PIO_MDDR
0x0FFF FFF0
PIO_PUDR
0x00F0 00F0
PIO_PUER
0x0F0F FF0F
PIO_ASR
0x0F0F 0000
PIO_BSR
0x00F0 0000
PIO_OWER
0x0000 000F
PIO_OWDR
0x0FFF FFF0
353
1768I–ATARM–09-Jul-09
27.6
Parallel Input/Output Controller (PIO) User Interface
Each I/O line controlled by the PIO Controller is associated with a bit in each of the PIO Controller User Interface registers.
Each register is 32 bits wide. If a parallel I/O line is not defined, writing to the corresponding bits has no effect. Undefined
bits read zero. If the I/O line is not multiplexed with any peripheral, the I/O line is controlled by the PIO Controller and
PIO_PSR returns 1 systematically.
Table 27-2.
PIO Register Mapping
Offset
Register
Name
Access
Reset Value
0x0000
PIO Enable Register
PIO_PER
Write-only
–
0x0004
PIO Disable Register
PIO_PDR
Write-only
–
0x0008
PIO Status Register (1)
PIO_PSR
Read-only
0x0000 0000
0x000C
Reserved
0x0010
PIO Output Enable Register
PIO_OER
Write-only
–
0x0014
PIO Output Disable Register
PIO_ODR
Write-only
–
0x0018
PIO Output Status Register
PIO_OSR
Read-only
0x0000 0000
0x001C
Reserved
0x0020
PIO Glitch Input Filter Enable Register
PIO_IFER
Write-only
–
0x0024
PIO Glitch Input Filter Disable Register
PIO_IFDR
Write-only
–
0x0028
PIO Glitch Input Filter Status Register
PIO_IFSR
Read-only
0x0000 0000
0x002C
Reserved
0x0030
PIO Set Output Data Register
PIO_SODR
Write-only
–
0x0034
PIO Clear Output Data Register
PIO_CODR
Write-only
–
0x0038
PIO Output Data Status Register(2)
PIO_ODSR
Read-only
0x0000 0000
0x003C
PIO Pin Data Status Register(3)
PIO_PDSR
Read-only
0x0040
PIO Interrupt Enable Register
PIO_IER
Write-only
–
0x0044
PIO Interrupt Disable Register
PIO_IDR
Write-only
–
0x0048
PIO Interrupt Mask Register
PIO_IMR
Read-only
0x0000 0000
PIO_ISR
Read-only
0x0000 0000
(4)
0x004C
PIO Interrupt Status Register
0x0050
PIO Multi-driver Enable Register
PIO_MDER
Write-only
–
0x0054
PIO Multi-driver Disable Register
PIO_MDDR
Write-only
–
0x0058
PIO Multi-driver Status Register
PIO_MDSR
Read-only
0x0000 0000
0x005C
Reserved
0x0060
PIO Pull-up Disable Register
PIO_PUDR
Write-only
–
0x0064
PIO Pull-up Enable Register
PIO_PUER
Write-only
–
0x0068
PIO Pad Pull-up Status Register
PIO_PUSR
Read-only
0x0000 0000
0x006C
Reserved
0x0070
PIO Peripheral A Select Register(5)
PIO_ASR
Write-only
–
0x0074
PIO Peripheral B Select Register
(5)
PIO_BSR
Write-only
–
0x0078
PIO AB Status Register(5)
PIO_ABSR
Read-only
0x0000 0000
354
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table 27-2.
PIO Register Mapping (Continued)
Offset
Register
0x007C
to
0x009C
Reserved
0x00A0
PIO Output Write Enable
0x00A4
Access
Reset Value
PIO_OWER
Write-only
–
PIO Output Write Disable
PIO_OWDR
Write-only
–
0x00A8
PIO Output Write Status Register
PIO_OWSR
Read-only
0x0000 0000
0x00AC
Reserved
Notes:
Name
1. Reset value of PIO_PSR depends on the product implementation.
2. PIO_ODSR is Read-only or Read/Write depending on PIO_OWSR I/O lines.
3. Reset value of PIO_PDSR depends on the level of the I/O lines.
4. PIO_ISR is reset at 0x0. However, the first read of the register may read a different value as input changes may have
occurred.
5. Only this set of registers clears the status by writing 1 in the first register and sets the status by writing 1 in the second
register.
355
1768I–ATARM–09-Jul-09
27.6.1
Name:
PIO Enable Register
PIO_PER
Access Type:
Write-only
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 - P31: PIO Enable
0 = No effect.
1 = Enables the PIO to control the corresponding pin (disables peripheral control of the pin).
27.6.2
Name:
PIO Disable Register
PIO_PDR
Access Type:
Write-only
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 - P31: PIO Disable
0 = No effect.
1 = Disables the PIO from controlling the corresponding pin (enables peripheral control of the pin).
356
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
27.6.3
Name:
PIO Status Register
PIO_PSR
Access Type:
Read-only
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 - P31: PIO Status
0 = PIO is inactive on the corresponding I/O line (peripheral is active).
1 = PIO is active on the corresponding I/O line (peripheral is inactive).
27.6.4
Name:
PIO Output Enable Register
PIO_OER
Access Type:
Write-only
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 - P31: Output Enable
0 = No effect.
1 = Enables the output on the I/O line.
357
1768I–ATARM–09-Jul-09
27.6.5
Name:
PIO Output Disable Register
PIO_ODR
Access Type:
Write-only
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 - P31: Output Disable
0 = No effect.
1 = Disables the output on the I/O line.
27.6.6
Name:
PIO Output Status Register
PIO_OSR
Access Type:
Read-only
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 - P31: Output Status
0 = The I/O line is a pure input.
1 = The I/O line is enabled in output.
358
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
27.6.7
Name:
PIO Input Filter Enable Register
PIO_IFER
Access Type:
Write-only
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 - P31: Input Filter Enable
0 = No effect.
1 = Enables the input glitch filter on the I/O line.
27.6.8
Name:
PIO Input Filter Disable Register
PIO_IFDR
Access Type:
Write-only
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 - P31: Input Filter Disable
0 = No effect.
1 = Disables the input glitch filter on the I/O line.
359
1768I–ATARM–09-Jul-09
27.6.9
Name:
PIO Input Filter Status Register
PIO_IFSR
Access Type:
Read-only
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 - P31: Input Filer Status
0 = The input glitch filter is disabled on the I/O line.
1 = The input glitch filter is enabled on the I/O line.
27.6.10
Name:
PIO Set Output Data Register
PIO_SODR
Access Type:
Write-only
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 - P31: Set Output Data
0 = No effect.
1 = Sets the data to be driven on the I/O line.
360
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
27.6.11
Name:
PIO Clear Output Data Register
PIO_CODR
Access Type:
Write-only
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 - P31: Set Output Data
0 = No effect.
1 = Clears the data to be driven on the I/O line.
27.6.12
Name:
PIO Output Data Status Register
PIO_ODSR
Access Type:
Read-only or Read/Write
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 - P31: Output Data Status
0 = The data to be driven on the I/O line is 0.
1 = The data to be driven on the I/O line is 1.
361
1768I–ATARM–09-Jul-09
27.6.13
Name:
PIO Pin Data Status Register
PIO_PDSR
Access Type:
Read-only
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 - P31: Output Data Status
0 = The I/O line is at level 0.
1 = The I/O line is at level 1.
27.6.14
Name:
PIO Interrupt Enable Register
PIO_IER
Access Type:
Write-only
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 - P31: Input Change Interrupt Enable
0 = No effect.
1 = Enables the Input Change Interrupt on the I/O line.
362
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
27.6.15
Name:
PIO Interrupt Disable Register
PIO_IDR
Access Type:
Write-only
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 - P31: Input Change Interrupt Disable
0 = No effect.
1 = Disables the Input Change Interrupt on the I/O line.
27.6.16
Name:
PIO Interrupt Mask Register
PIO_IMR
Access Type:
Read-only
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 - P31: Input Change Interrupt Mask
0 = Input Change Interrupt is disabled on the I/O line.
1 = Input Change Interrupt is enabled on the I/O line.
363
1768I–ATARM–09-Jul-09
27.6.17
Name:
PIO Interrupt Status Register
PIO_IMR
Access Type:
Read-only
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 - P31: Input Change Interrupt Mask
0 = No Input Change has been detected on the I/O line since PIO_ISR was last read or since reset.
1 = At least one Input Change has been detected on the I/O line since PIO_ISR was last read or since reset.
27.6.18
Name:
PIO Multi-driver Enable Register
PIO_MDER
Access Type:
Write-only
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 - P31: Multi Drive Enable
0 = No effect.
1 = Enables Multi Drive on the I/O line.
364
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
27.6.19
Name:
PIO Multi-driver Disable Register
PIO_MDDR
Access Type:
Write-only
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 - P31: Multi Drive Disable
0 = No effect.
1 = Disables Multi Drive on the I/O line.
27.6.20
Name:
PIO Multi-driver Status Register
PIO_MDSR
Access Type:
Read-only
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 - P31: Multi Drive Status
0 = The Multi Drive is disabled on the I/O line. The pin is driven at high and low level.
1 = The Multi Drive is enabled on the I/O line. The pin is driven at low level only.
365
1768I–ATARM–09-Jul-09
27.6.21
Name:
PIO Pull-Up Disable Register
PIO_PUDR
Access Type:
Write-only
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 - P31: Pull-Up Disable
0 = No effect.
1 = Disables the pull-up resistor on the I/O line.
27.6.22
Name:
PIO Pull-Up Enable Register
PIO_PUER
Access Type:
Write-only
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 - P31: Pull-Up Enable
0 = No effect.
1 = Enables the pull-up resistor on the I/O line.
366
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
27.6.23
Name:
PIO Pad Pull-Up Status Register
PIO_PUSR
Access Type:
Read-only
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 - P31: Pull-Up Status
0 = Pull-up resistor is enabled on the I/O line.
1 = Pull-up resistor is disabled on the I/O line.
27.6.24
Name:
PIO Peripheral A Select Register
PIO_ASR
Access Type:
Write-only
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 - P31: Peripheral A Select
0 = No effect.
1 = Assigns the I/O line to the Peripheral A function.
367
1768I–ATARM–09-Jul-09
27.6.25
Name:
PIO Peripheral B Select Register
PIO_BSR
Access Type:
Write-only
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 - P31: Peripheral B Select
0 = No effect.
1 = Assigns the I/O line to the peripheral B function.
27.6.26
Name:
PIO Peripheral AB Status Register
PIO_ABSR
Access Type:
Read-only
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 - P31: Peripheral A B Status
0 = The I/O line is assigned to the Peripheral A.
1 = The I/O line is assigned to the Peripheral B.
368
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
27.6.27
Name:
PIO Output Write Enable Register
PIO_OWER
Access Type:
Write-only
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 - P31: Output Write Enable
0 = No effect.
1 = Enables writing PIO_ODSR for the I/O line.
27.6.28
Name:
PIO Output Write Disable Register
PIO_OWDR
Access Type:
Write-only
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 - P31: Output Write Disable
0 = No effect.
1 = Disables writing PIO_ODSR for the I/O line.
369
1768I–ATARM–09-Jul-09
27.6.29
Name:
PIO Output Write Status Register
PIO_OWSR
Access Type:
Read-only
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 - P31: Output Write Status
0 = Writing PIO_ODSR does not affect the I/O line.
1 = Writing PIO_ODSR affects the I/O line.
370
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
28. Serial Peripheral Interface (SPI)
28.1
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 allows communication
between processors if an external processor is connected to the system.
The Serial Peripheral Interface is a shift register that serially transmits data bits to other SPIs.
During a data transfer, one SPI system acts as the master that controls the data flow, while the
other system acts as the slave, having data shifted into and out of it by the master. Different
CPUs can take turn being masters (Multiple Master Protocol versus 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.
The main features of the SPI are:
• Supports Communication with Serial External Devices
– 4 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
– 8- 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 PDC Channel Capabilities Optimizes Data Transfers
– One Channel for the Receiver, One Channel for the Transmitter
– Next Buffer Support
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1768I–ATARM–09-Jul-09
28.2
Block Diagram
Figure 28-1. Block Diagram
ASB
APB Bridge
PDC
APB
SPCK
MISO
PMC
MOSI
MCK
SPI Interface
PIO
NPCS0/NSS
NPCS1
NPCS2
Interrupt Control
NPCS3
SPI Interrupt
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28.3
Application Block Diagram
Figure 28-2. Application Block Diagram: Single Master/Multiple Slave Implementation
SPI Master
SPCK
SPCK
MISO
MISO
MOSI
MOSI
NPCS0
NSS
Slave 0
SPCK
NPCS1
NPCS2
NC
NPCS3
MISO
Slave 1
MOSI
NSS
SPCK
MISO
Slave 2
MOSI
NSS
Table 28-1.
Signal Description
Type
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
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28.4
Product Dependencies
28.4.1
I/O Lines
The pins used for interfacing the compliant external devices may be multiplexed with PIO lines.
The programmer must first program the PIO controllers to assign the SPI pins to their peripheral
functions.
28.4.2
Power Management
The SPI may be clocked through the Power Management Controller (PMC), thus the programmer must first have to configure the PMC to enable the SPI clock.
28.4.3
Interrupt
The SPI interface has an interrupt line connected to the Advanced Interrupt Controller (AIC).
Handling the SPI interrupt requires programming the AIC before configuring the SPI.
28.5
Functional Description
28.5.1
Master Mode Operations
When configured in Master Mode, the Serial Peripheral Interface controls data transfers to and
from the slave(s) connected to the SPI bus. The SPI drives the chip select(s) to the slave(s) and
the serial clock (SPCK). After enabling the SPI, a data transfer begins when the core writes to
the SPI_TDR (Transmit Data Register).
Transmit and Receive buffers maintain the data flow at a constant rate with a reduced requirement for high-priority interrupt servicing. When new data is available in the SPI_TDR, the SPI
continues to transfer data. If the SPI_RDR (Receive Data Register) has not been read before
new data is received, the Overrun Error (OVRES) flag is set.
Note:
As long as this flag is set, no data is loaded in the SPI_RDR. The user has to read the status register to clear it.
The programmable delay between the activation of the chip select and the start of the data
transfer (DLYBS), as well as the delay between each data transfer (DLYBCT), can be programmed for each of the four external chip selects. All data transfer characteristics, including the
two timing values, are programmed in registers SPI_CSR0 to SPI_CSR3 (Chip Select
Registers).
In Master Mode, the peripheral selection can be defined 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
Figure 28-7 and Figure 28-8 show the operation of the SPI in Master Mode. For details concerning the flag and control bits in these diagrams, see the “Serial Peripheral Interface (SPI) User
Interface” on page 382 and the subsequent register descriptions.
28.5.1.1
Fixed Peripheral Select
This mode is used for transferring memory blocks without the extra overhead in the transmit data
register to determine the peripheral.
Fixed Peripheral Select is activated by setting bit PS to zero in SPI_MR (Mode Register). The
peripheral is defined by the PCS field in SPI_MR.
This option is only available when the SPI is programmed in Master Mode.
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28.5.1.2
Variable Peripheral Select
Variable Peripheral Select is activated by setting bit PS to one. The PCS field in SPI_TDR is
used to select the destination peripheral. The data transfer characteristics are changed when
the selected peripheral changes, according to the associated chip select register.
The PCS field in the SPI_MR has no effect.
This option is only available when the SPI is programmed in Master Mode.
28.5.1.3
Chip Selects
The Chip Select lines are driven by the SPI only if it is programmed in Master Mode. These lines
are used to select the destination peripheral. The PCSDEC field in SPI_MR (Mode Register)
selects one to four peripherals (PCSDEC = 0) or up to 15 peripherals (PCSDEC = 1).
If Variable Peripheral Select is active, the chip select signals are defined for each transfer in the
PCS field in SPI_TDR. Chip select signals can thus be defined independently for each transfer.
If Fixed Peripheral Select is active, Chip Select signals are defined for all transfers by the field
PCS in SPI_MR. If a transfer with a new peripheral is necessary, the software must wait until the
current transfer is completed, then change the value of PCS in SPI_MR before writing new data
in SPI_TDR.
The value on the NPCS pins at the end of each transfer can be read in the SPI_RDR (Receive
Data Register).
By default, all NPCS signals are high (equal to one) before and after each transfer.
28.5.1.4
Clock Generation and Transfer Delays
The SPI Baud rate clock is generated by dividing the Master Clock (MCK) or the Master Clock
divided by 32 (if DIV32 is set in the Mode Register) by a value between 4 and 510. The divisor is
defined in the SCBR field in each Chip Select Register. The transfer speed can thus be defined
independently for each chip select signal.
Figure 28-3 shows a chip select transfer change and consecutive transfers on the same chip
selects. Three delays can be programmed to modify the transfer waveforms:
• Delay between chip selects, programmable only once for all the chip selects by writing the
field DLYBCS in the Mode Register. Allows insertion of a delay between release of one chip
select and before assertion of a new one.
• Delay before SPCK, independently programmable for each chip select by writing the field
DLYBS. Allows the start of SPCK to be delayed until after the chip select has been asserted.
• Delay between consecutive transfers, independently programmable for each chip select by
writing the field 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.
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1768I–ATARM–09-Jul-09
Figure 28-3. Programmable Delays
Chip Select 1
Chip Select 2
SPCK
DLYBCS
28.5.1.5
DLYBS
DLYBCT
DLYBCT
Mode Fault Detection
A mode fault is detected when the SPI is programmed in Master Mode and a low level is driven
by an external master on the NPCS0/NSS signal.
When a mode fault is detected, the MODF bit in the SPI_SR is set until the SPI_SR is read and
the SPI is disabled until re-enabled by bit SPIEN in the SPI_CR (Control Register).
By default, Mode Fault Detection is enabled. It is disabled by setting the MODFDIS bit in the SPI
Mode Register.
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28.5.1.6
Master Mode Flow Diagram
Figure 28-4. Master Mode Flow Diagram
SPI Enable
1
TDRE
0
0
Fixed peripheral
PS
1
Variable peripheral
NPCS = SPI_TDR(PCS)
NPCS = SPI_MR(PCS)
Delay DLYBS
Serializer = SPI_TDR(TD)
TDRE = 1
Data Transfer
SPI_RDR(RD) = Serializer
RDRF = 1
Delay DLYBCT
TDRE
1
0
0 Fixed peripheral
PS
NPCS = 0xF
1
Variable peripheral
Delay DLYBCS
SPI_TDR(PCS)
Same peripheral
New peripheral
NPCS = 0xF
Delay DLYBCS
NPCS = SPI_TDR(PCS)
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28.5.1.7
Master Mode Block Diagram
Figure 28-5. Master Mode Block Diagram
SPI_MR(DIV32)
MCK
0
SPCK Clock Generator
MCK/32
1
SPI_CSRx[15:0]
SPIDIS
SPCK
SPIEN
S
Q
R
SPI_RDR
PCS
RD
LSB
MSB
Serializer
MISO
SPI_TDR
PCS
MOSI
TD
NPCS3
NPCS2
NPCS1
SPI_MR(PS)
NPCS0
1
SPI_MR(PCS)
0
SPI_MR(MSTR)
SPI_SR
M
O
D
F
T
D
R
E
R
D
R
F
O
V
R
E
S
P
I
E
N
S
SPI_IER
SPI_IDR
SPI_IMR
SPI Interrupt
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28.5.2
SPI Slave Mode
In Slave Mode, the SPI waits for NSS to go active low before receiving the serial clock from an
external master.
In Slave Mode, CPOL, NCPHA and BITS fields of SPI_CSR0 are used to define the transfer
characteristics. The other Chip Select Registers are not used in Slave Mode.
In Slave Mode, the low and high pulse durations of the input clock on SPCK must be longer than
two Master Clock periods.
Figure 28-6. Slave Mode Block Diagram
SPCK
NSS
SPIDIS
SPIEN
S
Q
R
SPI_RDR
RD
LSB
MOSI
MSB
Serializer
MISO
SPI_TDR
TD
SPI_SR
S
P
I
E
N
S
T
D
R
E
R
D
R
F
O
V
R
E
SPI_IER
SPI_IDR
SPI_IMR
SPI Interrupt
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1768I–ATARM–09-Jul-09
28.5.3
Data Transfer
Four modes are used for data transfers. These modes correspond to combinations of a pair of
parameters called clock polarity (CPOL) and clock phase (NCPHA) that determine the edges of
the clock signal on which the data are 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 28-2 shows the four modes and corresponding parameter settings.
Table 28-2.
SPI Bus Protocol Mode
SPI Mode
CPOL
NCPHA
0
0
1
1
0
0
2
1
1
3
1
0
Figure 28-7 and Figure 28-8 show examples of data transfers.
Figure 28-7. SPI Transfer Format (NCPHA = 1, 8 bits per transfer)
SPCK cycle (for reference)
1
2
3
5
4
6
8
7
SPCK
(CPOL = 0)
(Mode 1)
SPCK
(CPOL = 1)
(Mode 3)
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 normally MSB of previous character received.
380
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Figure 28-8. SPI Transfer Format (NCPHA = 0, 8 bits per transfer)
1
SPCK cycle (for reference)
2
3
5
4
6
8
7
SPCK
(CPOL = 0)
(Mode 0)
SPCK
(CPOL = 1)
(Mode 2)
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 normally LSB of previous character transmitted.
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1768I–ATARM–09-Jul-09
28.6
Serial Peripheral Interface (SPI) User Interface
Table 28-3.
SPI Register Mapping
Offset
Register Name
Access
Reset
0x00
Control Register
SPI_CR
Write-only
---
0x04
Mode Register
SPI_MR
Read/Write
0x0
0x08
Receive Data Register
SPI_RDR
Read-only
0x0
0x0C
Transmit Data Register
SPI_TDR
Write-only
---
0x10
Status Register
SPI_SR
Read-only
0x000000F0
0x14
Interrupt Enable Register
SPI_IER
Write-only
---
0x18
Interrupt Disable Register
SPI_IDR
Write-only
---
0x1C
Interrupt Mask Register
SPI_IMR
Read-only
0x0
0x20 - 0x2C
Reserved
0x30
Chip Select Register 0
SPI_CSR0
Read/Write
0x0
0x34
Chip Select Register 1
SPI_CSR1
Read/Write
0x0
0x38
Chip Select Register 2
SPI_CSR2
Read/Write
0x0
0x3C
Chip Select Register 3
SPI_CSR3
Read/Write
0x0
0x40 - 0xFF
0x100 - 0x124
382
Register
Reserved
Reserved for the PDC
AT91RM9200
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28.6.1
Name:
SPI Control Register
SPI_CR
Access Type:
Write-only
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
SWRST
–
–
–
–
–
SPIDIS
SPIEN
• SPIEN: SPI Enable
0 = No effect.
1 = Enables the SPI to transfer and receive data.
• SPIDIS: SPI Disable
0 = No effect.
1 = Disables the SPI.
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 control register is written, the SPI is disabled
• SWRST: SPI Software Reset
0 = No effect.
1 = Reset the SPI.
A software-triggered hardware reset of the SPI interface is performed.
383
1768I–ATARM–09-Jul-09
28.6.2
Name:
SPI Mode Register
SPI_MR
Access Type:
31
Read/Write
30
29
28
27
26
19
18
25
24
17
16
DLYBCS
23
22
21
20
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
–
–
–
–
–
PCS
7
6
5
4
3
2
1
0
LLB
–
–
MODFDIS
DIV32
PCSDEC
PS
MSTR
• MSTR: Master/Slave Mode
0 = SPI is in Slave mode.
1 = SPI is in Master mode.
• PS: Peripheral Select
0 = Fixed Peripheral Select.
1 = Variable Peripheral Select.
• 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 16 Chip Select signals can be generated with the four lines using an external 4- to 16-bit
decoder.
The Chip Select Registers define the characteristics of the 16 chip selects according to the following rules:
SPI_CSR0 defines peripheral chip select signals 0 to 3.
SPI_CSR1 defines peripheral chip select signals 4 to 7.
SPI_CSR2 defines peripheral chip select signals 8 to 11.
SPI_CSR3 defines peripheral chip select signals 12 to 15*.
*Note: The 16th state corresponds to a state in which all chip selects are inactive. This allows a different clock configuration
to be defined by each chip select register.
• DIV32: Clock Selection
0 = The SPI operates at MCK.
1 = The SPI operates at MCK/32.
• MODFDIS: Mode Fault Detection
0 = Mode fault detection is enabled.
1 = Mode fault detection is disabled.
• LLB: Local Loopback Enable
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0 = Local loopback path disabled
1 = Local loopback path enabled
LLB controls the local loopback on the data serializer for testing in Master Mode only.
• PCS: Peripheral Chip Select
This field is only used if Fixed Peripheral Select is active (PS = 0).
If PCSDEC = 0:
PCS = xxx0
NPCS[3:0] = 1110
PCS = xx01
NPCS[3:0] = 1101
PCS = x011
NPCS[3:0] = 1011
PCS = 0111
NPCS[3:0] = 0111
PCS = 1111
forbidden (no peripheral is selected)
(x = don’t care)
If PCSDEC = 1:
NPCS[3:0] output signals = PCS
• DLYBCS: Delay Between Chip Selects
This field defines the delay from NPCS inactive to the activation of another NPCS. The DLYBCS time guarantees non-overlapping 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 MCK periods (or 192 MCK periods if DIV32 is set) will be inserted by default.
Otherwise, the following equation determines the delay:
If DIV32 is 0:
Delay Between Chip Selects = DLYBCS ⁄ MCK
If DIV32 is 1:
Delay Between Chip Selects = DLYBCS × 32 ⁄ MCK
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1768I–ATARM–09-Jul-09
28.6.3
Name:
SPI Receive Data Register
SPI_RDR
Access Type:
Read-only
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
7
6
5
4
RD
• RD: Receive Data
Data received by the SPI Interface is stored in this register right-justified. Unused bits read zero.
• 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.
386
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28.6.4
Name:
SPI Transmit Data Register
SPI_TDR
Access Type:
Write-only
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
TD
7
6
5
4
TD
• 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
transmit data register in a right-justified format.
PCS: Peripheral Chip Select
This field is only used if Variable Peripheral Select is active (PS = 1).
If PCSDEC = 0:
PCS = xxx0
NPCS[3:0] = 1110
PCS = xx01
NPCS[3:0] = 1101
PCS = x011
NPCS[3:0] = 1011
PCS = 0111
NPCS[3:0] = 0111
PCS = 1111
forbidden (no peripheral is selected)
(x = don’t care)
If PCSDEC = 1:
NPCS[3:0] output signals = PCS
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1768I–ATARM–09-Jul-09
28.6.5
Name:
SPI Status Register
SPI_SR
Access Type:
Read-only
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
–
–
–
–
–
–
–
–
7
6
5
4
3
2
1
0
TXBUFE
RXBUFF
ENDTX
ENDRX
OVRES
MODF
TDRE
RDRF
• RDRF: Receive Data Register Full
0 = No data has been received since the last read of SPI_RDR
1 = Data has been received and the received data has been transferred from the serializer to SPI_RDR since the last read
of SPI_RDR.
• TDRE: Transmit Data Register Empty
0 = Data has been written to SPI_TDR and not yet transferred to the serializer.
1 = The last data written in the Transmit Data Register has been transferred to the serializer.
TDRE equals zero when the SPI is disabled or at reset. The SPI enable command sets this bit to one.
• MODF: Mode Fault Error
0 = No Mode Fault has been detected since the last read of SPI_SR.
1 = A Mode Fault occurred since the last read of the SPI_SR.
• OVRES: Overrun Error Status
0 = No overrun has been detected since the last read of SPI_SR.
1 = An overrun has occurred since the last read of SPI_SR.
An overrun occurs when SPI_RDR is loaded at least twice from the serializer since the last read of the SPI_RDR.
• ENDRX: End of RX buffer
0 = The Receive Counter Register has not reached 0 since the last write in SPI_RCR or SPI_RNCR.
1 = The Receive Counter Register has reached 0 since the last write in SPI_RCR or SPI_RNCR.
• ENDTX: End of TX buffer
0 = The Transmit Counter Register has not reached 0 since the last write in SPI_TCR or SPI_TNCR.
1 = The Transmit Counter Register has reached 0 since the last write in SPI_TCR or SPI_TNCR.
• RXBUFF: RX Buffer Full
0 = SPI_RCR or SPI_RNCR have a value other than 0.
1 = Both SPI_RCR and SPI_RNCR have a value of 0.
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• TXBUFE: TX Buffer Empty
0 = SPI_TCR or SPI_TNCR have a value other than 0.
1 = Both SPI_TCR and SPI_TNCR have a value of 0.
• SPIENS: SPI Enable Status
0 = SPI is disabled.
1 = SPI is enabled.
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28.6.6
Name:
SPI Interrupt Enable Register
SPI_IER
Access Type:
Write-only
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
TXBUFE
RXBUFF
ENDTX
ENDRX
OVRES
MODF
TDRE
RDRF
• RDRF: Receive Data Register Full Interrupt Enable
• TDRE: SPI Transmit Data Register Empty Interrupt Enable
• MODF: Mode Fault Error Interrupt Enable
• OVRES: Overrun Error Interrupt Enable
• ENDRX: End of Receive Buffer Interrupt Enable
• ENDTX: End of Transmit Buffer Interrupt Enable
• RXBUFF: Receive Buffer Full Interrupt Enable
• TXBUFE: Transmit Buffer Empty Interrupt Enable
0 = No effect.
1 = Enables the corresponding interrupt.
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28.6.7
Name:
SPI Interrupt Disable Register
SPI_IDR
Access Type:
Write-only
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
TXBUFE
RXBUFF
ENDTX
ENDRX
OVRES
MODF
TDRE
RDRF
• RDRF: Receive Data Register Full Interrupt Disable
• TDRE: SPI Transmit Data Register Empty Interrupt Disable
• MODF: Mode Fault Error Interrupt Disable
• OVRES: Overrun Error Interrupt Disable
• ENDRX: End of Receive Buffer Interrupt Disable
• ENDTX: End of Transmit Buffer Interrupt Disable
• RXBUFF: Receive Buffer Full Interrupt Disable
• TXBUFE: Transmit Buffer Empty Interrupt Disable
0 = No effect.
1 = Disables the corresponding interrupt.
391
1768I–ATARM–09-Jul-09
28.6.8
Name:
SPI Interrupt Mask Register
SPI_IMR
Access Type:
Read-only
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
TXBUFE
RXBUFF
ENDTX
ENDRX
OVRES
MODF
TDRE
RDRF
• RDRF: Receive Data Register Full Interrupt Mask
• TDRE: SPI Transmit Data Register Empty Interrupt Mask
• MODF: Mode Fault Error Interrupt Mask
• OVRES: Overrun Error Interrupt Mask
• ENDRX: End of Receive Buffer Interrupt Mask
• ENDTX: End of Transmit Buffer Interrupt Mask
• RXBUFF: Receive Buffer Full Interrupt Mask
• TXBUFE: Transmit Buffer Empty Interrupt Mask
0 = The corresponding interrupt is not enabled.
1 = The corresponding interrupt is enabled.
392
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
28.6.9
Name:
SPI Chip Select Register
SPI_CSR0... SPI_CSR3
Access Type:
31
Read/Write
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
DLYBCT
23
22
21
20
DLYBS
15
14
13
12
SCBR
7
6
5
4
BITS
3
2
1
0
–
–
NCPHA
CPOL
• CPOL: Clock Polarity
0 = The inactive state value of SPCK is logic level zero.
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 NCPHA to produce the
required clock/data relationship between master and slave devices.
• NCPHA: Clock Phase
0 = Data is changed on the leading edge of SPCK and captured on the following edge of SPCK.
1 = Data is captured on the leading edge of SPCK and changed on the following 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.
• BITS: Bits Per Transfer
The BITS field determines the number of data bits transferred. Reserved values should not be used.
BITS[3:0]
Bits Per Transfer
0000
8
0001
9
0010
10
0011
11
0100
12
0101
13
0110
14
0111
15
1000
16
1001
Reserved
1010
Reserved
1011
Reserved
1100
Reserved
1101
Reserved
1110
Reserved
1111
Reserved
393
1768I–ATARM–09-Jul-09
• SCBR: Serial Clock Baud Rate
In Master Mode, the SPI Interface uses a modulus counter to derive the SPCK baud rate from the Master Clock MCK. The
Baud rate is selected by writing a value from 2 to 255 in the field SCBR. The following equation determines the SPCK baud
rate:
If DIV32 is 0:
SPCK Baudrate = MCK ⁄ ( 2 × SCBR )
If DIV32 is 1:
SPCK Baudrate = MCK ⁄ ( 64 × SCBR )
Giving SCBR a value of zero or one disables the baud rate generator. SPCK is disabled and assumes its inactive state
value. No serial transfers may occur. At reset, baud rate is disabled.
• 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:
If DIV32 is 0:
Delay Before SPCK = DLYBS ⁄ MCK
If DIV32 is 1:
Delay Before SPCK = 32 × DLYBS ⁄ MCK
• 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, a minimum delay of four MCK cycles are inserted (or 128 MCK cycles when DIV32 is set)
between two consecutive characters.
Otherwise, the following equation determines the delay:
If DIV32 is 0:
Delay Between Consecutive Transfers = 32 × DLYBCT ⁄ MCK
If DIV32 is 1:
Delay Between Consecutive Transfers = 1024 × DLYBCT ⁄ MCK
394
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
29. Two-wire Interface (TWI)
29.1
Overview
The Two-wire Interface (TWI) interconnects components on a unique two-wire bus, made up of
one clock line and one data line with speeds of up to 400 Kbits per second, based on a byte-oriented transfer format. It can be used with any Atmel two-wire bus serial EEPROM. The TWI is
programmable as a master with sequential or single-byte access.
A configurable baud rate generator permits the output data rate to be adapted to a wide range of
core clock frequencies.
The main features of the TWI are:
• Compatibility with standard two-wire serial memory
• One, two or three bytes for slave address
• Sequential Read/Write operations
29.2
Block Diagram
Figure 29-1. Block Diagram
APB Bridge
TWCK
PIO
PMC
MCK
TWD
Two-wire
Interface
TWI
Interrupt
29.3
AIC
Application Block Diagram
Figure 29-2. Application Block Diagram
VDD
R
Host with
TWI
Interface
R
TWD
TWCK
AT24LC16
U1
Slave 1
AT24LC16
U2
Slave 2
LCD Controller
U3
Slave 3
395
1768I–ATARM–09-Jul-09
Table 29-1.
29.4
29.4.1
I/O Lines Description
Pin Name
Pin Description
Type
TWD
Two-wire Serial Data
Input/Output
TWCK
Two-wire Serial Clock
Input/Output
Product Dependencies
I/O Lines
Both TWD and TWCK are bi-directional lines, connected to a positive supply voltage via a current source or pull-up resistor (see Figure 29-2 on page 395). When the bus is free, both lines
are high. The output stages of devices connected to the bus must have an open-drain or opencollector to perform the wired-AND function.
TWD and TWCK pins may be multiplexed with PIO lines. To enable the TWI, the programmer
must perform the following steps:
• Program the PIO controller to:
– Dedicate TWD and TWCK as peripheral lines.
– Define TWD and TWCK as open-drain.
29.4.2
Power Management
• Enable the peripheral clock.
The TWI interface may be clocked through the Power Management Controller (PMC), thus the
programmer must first configure the PMC to enable the TWI clock.
29.4.3
Interrupt
The TWI interface has an interrupt line connected to the Advanced Interrupt Controller (AIC). In
order to handle interrupts, the AIC must be programmed before configuring the TWI.
29.5
29.5.1
Functional Description
Transfer Format
The data put on the TWD line must be eight 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 29-4 on page 397).
Each transfer begins with a START condition and terminates with a STOP condition (see Figure
29-3 on page 397).
• 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.
396
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Figure 29-3.
START and STOP Conditions
TWD
TWCK
Start
Stop
Figure 29-4. Transfer Format
TWD
TWCK
Start
29.5.2
Address
R/W
Ack
Data
Ack
Data
Ack
Stop
Modes of Operation
The TWI has two modes of operations:
• Master transmitter mode
• Master receiver mode
The TWI Control Register (TWI_CR) allows configuration of the interface in Master Mode. In this
mode, it generates the clock according to the value programmed in the Clock Waveform Generator Register (TWI_CWGR). This register defines the TWCK signal completely, enabling the
interface to be adapted to a wide range of clocks.
29.5.3
Transmitting Data
After the master initiates a Start condition, it sends a 7-bit slave address, configured in the Master Mode register (DADR in TWI_MMR), to notify the slave device. The bit following the slave
address indicates the transfer direction (write or read). If this bit is 0, it indicates a write operation
(transmit operation). If the bit is 1, it indicates a request for data read (receive operation).
The TWI transfers require the slave to acknowledge each received byte. During the acknowledge clock 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 NAK bit in the status register if the slave does not acknowledge the byte. As with the
other status bits, an interrupt can be generated if enabled in the interrupt enable register
(TWI_IER). After writing in the transmit-holding register (TWI_THR), setting the START bit in the
control register starts the transmission. The data is shifted in the internal shifter and when an
acknowledge is detected, the TXRDY bit is set until a new write in the TWI_THR (see Figure 296 on page 398). The master generates a stop condition to end the transfer.
The read sequence begins by setting the START bit. When the RXRDY bit is set in the status
register, a character has been received in the receive-holding register (TWI_RHR). The RXRDY
bit is reset when reading the TWI_RHR.
The TWI interface performs various transfer formats (7-bit slave address, 10-bit slave address).
The three internal address bytes are configurable through the Master Mode register
(TWI_MMR). If the slave device supports only a 7-bit address, the IADRSZ must be set to 0. For
397
1768I–ATARM–09-Jul-09
slave address higher than seven bits, the user must configure the address size (IADRSZ) and
set the other slave address bits in the internal address register (TWI_IADR).
Figure 29-5. Master Write with One, Two or Three Bytes Internal Address and One Data Byte
Three bytes internal address
S
TWD
DADR
W
A
IADR(23:16)
A
IADR(15:8)
A
IADR(7:0)
A
W
A
IADR(15:8)
A
IADR(7:0)
A
DATA
A
W
A
IADR(7:0)
A
DATA
A
DATA
A
P
Two bytes internal address
S
TWD
DADR
P
One byte internal address
S
TWD
DADR
P
Figure 29-6. Master Write with One Byte Internal Address and Multiple Data Bytes
S
TWD
DADR
W
A
IADR(7:0)
DATA
A
A
DATA
DATA
A
A
P
TXCOMP
Write THR
TXRDY
Write THR
Write THR
Write THR
Figure 29-7. Master Read with One, Two or Three Bytes Internal Address and One Data Byte
Three bytes internal address
S
TWD
DADR
A
W
IADR(23:16)
A
A
IADR(15:8)
IADR(7:0)
A
S
DADR
R
A
DATA
N
P
Two bytes internal address
S
TWD
DADR
W
A
IADR(15:8)
A
IADR(7:0)
A
S
W
A
IADR(7:0)
A
S
R
A
DADR
R
A
DATA
N
P
DATA
N
P
One byte internal address
TWD
S
DADR
DADR
DATA
N
P
Figure 29-8. Master Read with One Byte Internal Address and Multiple Data Bytes
TWD
S
DADR
W
A
IADR(7:0)
A
S
DADR
R
A
DATA
A
TXCOMP
Write START Bit
Write STOP Bit
RXRDY
Read RHR
Read RHR
• S = Start
398
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
• P = Stop
• W = Write
• R = Read
• A = Acknowledge
• N = Not Acknowledge
• DADR= Device Address
• IADR = Internal Address
Figure 29-9 shows a byte write to an Atmel AT24LC512 EEPROM. This demonstrates the use of
internal addresses to access the device.
Figure 29-9.
Internal Address Usage
S
T
A
R
T
Device
Address
W
R
I
T
E
FIRST
WORD ADDRESS
SECOND
WORD ADDRESS
S
T
O
P
DATA
0
M
S
B
29.5.4
LR A
S / C
BW K
M
S
B
A
C
K
LA
SC
BK
A
C
K
Read/Write Flowcharts
The following flowcharts shown in Figure 29-10 on page 400 and in Figure 29-11 on page 401
give examples for read and write operations in Master Mode. A polling or interrupt method can
be used to check the status bits. The interrupt method requires that the interrupt enable register
(TWI_IER) be configured first.
399
1768I–ATARM–09-Jul-09
Figure 29-10. TWI Write in Master Mode
START
Set TWI clock:
TWI_CWGR = clock
Set the control register:
- Master enable
TWI_CR = TWI_MSEN
Set the Master Mode register:
- Device slave address
- Internal address size
- Transfer direction bit
Write ==> bit MREAD = 0
Internal address size = 0?
Set the internal address
TWI_IADR = address
Yes
Load transmit register
TWI_THR = Data to send
Start the transfer
TWI_CR = TWI_START
Read status register
TWI_THR = data to send
TXRDY = 0?
Yes
Data to send?
Yes
Stop the transfer
TWI_CR = TWI_STOP
Read status register
TXCOMP = 0?
END
400
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Figure 29-11. TWI Read in Master Mode
START
Set TWI clock:
TWI_CWGR = clock
Set the control register:
- Master enable
TWI_CR = TWI_MSEN
Set the Master Mode register:
- Device slave address
- Internal address size
- Transfer direction bit
Read ==> bit MREAD = 0
Internal address size = 0?
Set the internal address
TWI_IADR = address
Yes
Start the transfer
TWI_CR = TWI_START
Read status register
RXRDY = 0?
Yes
Data to read?
Yes
Stop the transfer
TWI_CR = TWI_STOP
Read status register
Yes
TXCOMP = 0?
END
401
1768I–ATARM–09-Jul-09
29.6
Two-wire Interface (TWI) User Interface
Table 29-2.
TWI Register Mapping
Offset
Register
Name
Access
Reset Value
0x0000
Control Register
TWI_CR
Write-only
N/A
0x0004
Master Mode Register
TWI_MMR
Read/Write
0x0000
0x0008
Reserved
0x000C
Internal Address Register
TWI_IADR
Read/Write
0x0000
0x0010
Clock Waveform Generator Register
TWI_CWGR
Read/Write
0x0000
0x0020
Status Register
TWI_SR
Read-only
0x0008
0x0024
Interrupt Enable Register
TWI_IER
Write-only
N/A
0x0028
Interrupt Disable Register
TWI_IDR
Write-only
N/A
0x002C
Interrupt Mask Register
TWI_IMR
Read-only
0x0000
0x0030
Receive Holding Register
TWI_RHR
Read-only
0x0000
0x0034
Transmit Holding Register
TWI_THR
Read/Write
0x0000
402
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
29.6.1
TWI Control Register
Register Name:
TWI_CR
Access Type:
Write-only
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
SWRST
6
–
5
–
4
–
3
MSDIS
2
MSEN
1
STOP
0
START
• START: Send a START Condition
0 = No effect.
1 = A frame beginning with a START bit is transmitted according to the features defined in the mode register.
This action is necessary when the TWI peripheral wants to read data from a slave. When configured in Master Mode with a
write operation, a frame is sent with the mode register as soon as the user writes a character in the holding register.
• STOP: Send a STOP Condition
0 = No effect.
1 = STOP Condition is sent just after completing the current byte transmission in master read or write mode.
In single data byte master read or write, the START and STOP must both be set.
In multiple data bytes master read or write, the STOP must be set before ACK/NACK bit transmission.
In master read mode, if a NACK bit is received, the STOP is automatically performed.
In multiple data write operation, when both THR and shift register are empty, a STOP condition is automatically sent.
• MSEN: TWI Master Transfer Enabled
0 = No effect.
1 = If MSDIS = 0, the master data transfer is enabled.
• MSDIS: TWI Master Transfer Disabled
0 = No effect.
1 = The master data transfer is disabled, all pending data is transmitted. The shifter and holding characters (if it contains
data) are transmitted in case of write operation. In read operation, the character being transferred must be completely
received before disabling.
• SWRST: Software Reset
0 = No effect.
1 = Equivalent to a system reset.
403
1768I–ATARM–09-Jul-09
29.6.2
TWI Master Mode Register
Register Name:
TWI_MMR
Address Type:
Read/Write
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
21
20
19
DADR
18
17
16
15
–
14
–
13
–
12
MREAD
11
–
10
–
9
7
–
6
–
5
–
4
–
3
–
2
–
1
–
8
IADRSZ
0
–
• IADRSZ: Internal Device Address Size
IADRSZ[9:8]
0
0
No internal device address (Byte command protocol)
0
1
One-byte internal device address
1
0
Two-byte internal device address
1
1
Three-byte internal device address
• MREAD: Master Read Direction
0 = Master write direction.
1 = Master read direction.
• DADR: Device Address
The device address is used in Master Mode to access slave devices in read or write mode.
404
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
29.6.3
TWI Internal Address Register
Register Name:
TWI_IADR
Access Type:
Read/Write
31
–
30
–
29
–
28
–
23
22
21
20
27
–
26
–
25
–
24
–
19
18
17
16
11
10
9
8
3
2
1
0
IADR
15
14
13
12
IADR
7
6
5
4
IADR
• IADR: Internal Address
0, 1, 2 or 3 bytes depending on IADRSZ. Low significant byte address in 10-bit mode addresses.
29.6.4
TWI Clock Waveform Generator Register
Register Name:
TWI_CWGR
Access Type:
Read/Write
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
17
CKDIV
16
15
14
13
12
11
10
9
8
3
2
1
0
CHDIV
7
6
5
4
CLDIV
• CLDIV: Clock Low Divider
The TWCK low period is defined as follows:
T low = ( ( CLDIV × 2
CKDIV
) + 3 ) × T MCK
• CHDIV: Clock High Divider
The TWCK high period is defined as follows:
T high = ( ( CHDIV × 2
CKDIV
) + 3 ) × T MCK
• CKDIV: Clock Divider
The CKDIV is used to increase both TWCK high and low periods.
405
1768I–ATARM–09-Jul-09
29.6.5
TWI Status Register
Register Name:
TWI_SR
Access Type:
Read-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
–
14
–
13
–
12
–
11
–
10
–
9
–
8
NACK
7
UNRE
6
OVRE
5
–
4
–
3
–
2
TXRDY
1
RXRDY
0
TXCOMP
• TXCOMP: Transmission Completed
0 = In master, during the length of the current frame. In slave, from START received to STOP received.
1 = When both holding and shifter registers are empty and STOP condition has been sent (in Master) or when MSEN is set
(enable TWI).
• RXRDY: Receive Holding Register Ready
0 = No character has been received since the last TWI_RHR read operation.
1 = A byte has been received in the TWI_RHR since the last read.
• TXRDY: Transmit Holding Register Ready
0 = The transmit holding register has not been transferred into shift register. Set to 0 when writing into TWI_THR register.
1 = As soon as data byte is transferred from TWI_THR to internal shifter or if a NACK error is detected, TXRDY is set at the
same time as TXCOMP and NACK. TXRDY is also set when MSEN is set (enable TWI).
• OVRE: Overrun Error
0 = TWI_RHR has not been loaded while RXRDY was set
1 = TWI_RHR has been loaded while RXRDY was set. Reset by read in TWI_SR when TXCOMP is set.
• UNRE: Underrun Error
0 = No underrun error
1 = No valid data in TWI_THR (TXRDY set) while trying to load the data shifter. This action automatically generated a
STOP bit in Master Mode. Reset by read in TWI_SR when TXCOMP is set.
• NACK: Not Acknowledged
0 = Each data byte has been correctly received by the far-end side TWI slave component.
1 = A data byte has not been acknowledged by the slave component. Set at the same time as TXCOMP. Reset after read.
406
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
29.6.6
TWI Interrupt Enable Register
Register Name:
TWI_IER
Access Type:
Write-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
–
14
–
13
–
12
–
11
–
10
–
9
–
8
NACK
7
UNRE
6
OVRE
5
–
4
–
3
–
2
TXRDY
1
RXRDY
0
TXCOMP
• TXCOMP: Transmission Completed
• RXRDY: Receive Holding Register Ready
• TXRDY: Transmit Holding Register Ready
• OVRE: Overrun Error
• UNRE: Underrun Error
• NACK: Not Acknowledge
0 = No effect.
1 = Enables the corresponding interrupt.
407
1768I–ATARM–09-Jul-09
29.6.7
TWI Interrupt Disable Register
Register Name:
TWI_IDR
Access Type:
Write-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
–
14
–
13
–
12
–
11
–
10
–
9
–
8
NACK
7
UNRE
6
OVRE
5
–
4
–
3
–
2
TXRDY
1
RXRDY
0
TXCOMP
• TXCOMP: Transmission Completed
• RXRDY: Receive Holding Register Ready
• TXRDY: Transmit Holding Register Ready
• OVRE: Overrun Error
• UNRE: Underrun Error
• NACK: Not Acknowledge
0 = No effect.
1 = Disables the corresponding interrupt.
408
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
29.6.8
TWI Interrupt Mask Register
Register Name:
TWI_IMR
Access Type:
Read-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
–
14
–
13
–
12
–
11
–
10
–
9
–
8
NACK
7
UNRE
6
OVRE
5
–
4
–
3
–
2
TXRDY
1
RXRDY
0
TXCOMP
• TXCOMP: Transmission Completed
• RXRDY: Receive Holding Register Ready
• TXRDY: Transmit Holding Register Ready
• OVRE: Overrun Error
• UNRE: Underrun Error
• NACK: Not Acknowledge
0 = The corresponding interrupt is disabled.
1 = The corresponding interrupt is enabled.
29.6.9
TWI Receive Holding Register
Register Name:
TWI_RHR
Access Type:
Read-only
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: Master or Slave Receive Holding Data
409
1768I–ATARM–09-Jul-09
29.6.10 TWI Transmit Holding Register
Register Name:
TWI_THR
Access Type:
Read/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
TXDATA
• TXDATA: Master or Slave Transmit Holding Data
410
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
30. Universal Synchronous Asynchronous Receiver Transceiver (USART)
30.1
Overview
The Universal Synchronous Asynchronous Receiver Transceiver (USART) provides one full
duplex universal synchronous asynchronous serial link. Data frame format is widely programmable (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. Multi-drop 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 busses, 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 PDC provides chained buffer management without any intervention of the processor.
Important features of the USART are:
• Programmable Baud Rate Generator
• 5- to 9-bit Full-duplex Synchronous or Asynchronous Serial Communications(1)
– 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 Multi-Drop 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
• Test Modes
– Remote Loopback, Local Loopback, Automatic Echo
• Supports Connection of Two Peripheral DMA Controller Channels (PDC)
– Offer Buffer Transfer without Processor Intervention
Note:
1. The 9-bit Character Length Mode cannot be used with the peripheral DMA Controller (PDC)
411
1768I–ATARM–09-Jul-09
30.2
Block Diagram
Figure 30-1. USART Block Diagram
Peripheral Data
Controller
Channel
Channel
PIO
Controller
USART
RXD
Receiver
RTS
AIC
TXD
USART
Interrupt
Transmitter
CTS
DTR
PMC
Modem
Signals
Control
MCK
DIV
DSR
DCD
MCK/DIV
RI
SLCK
Baud Rate
Generator
SCK
User Interface
APB
412
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
30.3
Application Block Diagram
Figure 30-2.
Application Block Diagram
IrLAP
PPP
Modem
Driver
Serial
Driver
Field Bus
Driver
EMV
Driver
IrDA
Driver
USART
RS232
Drivers
RS232
Drivers
RS485
Drivers
Serial
Port
Differential
Bus
Smart
Card
Slot
IrDA
Transceivers
Modem
PSTN
30.4
I/O Lines Description
Table 30-1.
I/O Line Description
Name
Description
Type
SCK
Serial Clock
I/O
TXD
Transmit Serial Data
I/O
RXD
Receive Serial Data
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
Input
Low
RTS
Request to Send
Output
Low
30.5
30.5.1
Active Level
Product Dependencies
I/O Lines
The pins used for interfacing the USART may be multiplexed with the PIO lines. The programmer must first program the PIO 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 PIO Controller.
All the pins of the modems may or may not be implemented on the USART within a product. Frequently, only the USART1 is fully equipped with all the modem signals. For the other USARTs of
the product not equipped with the corresponding pin, the associated control bits and statuses
have no effect on the behavior of the USART.
413
1768I–ATARM–09-Jul-09
30.5.2
Power Management
The USART is not continuously clocked. The programmer must first enable the USART Clock in
the Power Management Controller (PMC) before using the USART. However, if the application
does not require USART operations, the USART clock can be stopped when not needed and be
restarted later. In this case, the USART will resume its operations where it left off.
Configuring the USART does not require the USART clock to be enabled.
30.5.3
Interrupt
The USART interrupt line is connected on one of the internal sources of the Advanced Interrupt
Controller. Using the USART interrupt requires the AIC to be programmed first. Note that it is not
recommended to use the USART interrupt line in edge sensitive mode.
30.6
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 multi-drop 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 Multi-Drop 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
• Test modes
– remote loopback, local loopback, automatic echo
414
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
30.6.1
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 (US_MR) between:
• the Master Clock MCK
• A division of the Master Clock, the divider being product dependent, but generally set to 8
• the external clock, available on the SCK 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 (US_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 SCK clock is selected, the duration of the low and high levels of the signal provided on the SCK pin must be longer than a Master Clock (MCK) period. The frequency of the
signal provided on SCK must be at least 4.5 times lower than MCK.
Figure 30-3. Baud Rate Generator
USCLKS
MCK
MCK/DIV
SCK
Reserved
CD
CD
SCK
0
1
2
16-bit Counter
FIDI
>1
3
1
0
0
0
SYNC
OVER
Sampling
Divider
0
Baud Rate
Clock
1
1
SYNC
USCLKS = 3
30.6.1.1
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 (US_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 US_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.
The following formula performs the calculation of the Baud Rate.
SelectedClock
Baudrate = -------------------------------------------( 8 ( 2 – Over )CD )
This gives a maximum baud rate of MCK divided by 8, assuming that MCK is the highest possible clock and that OVER is programmed at 1.
415
1768I–ATARM–09-Jul-09
Baud Rate Calculation Example
Table 30-2 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 30-2.
Baud Rate Example (OVER = 0)
Calculation
Result
Actual
Baud Rate
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%
70 000 000
38 400
113.93
114
38 377.19
0.06%
CD
Error
Bit/s
The baud rate is calculated with the following formula:
BaudRate = MCK ⁄ CD × 16
The baud rate error is calculated with the following formula. It is not recommended to work with
an error higher than 5%.
ExpectedBaudRate
Error = 1 – ⎛⎝ ---------------------------------------------------⎞⎠
ActualBaudRate
30.6.1.2
416
Baud Rate in Synchronous Mode
If the USART is programmed to operate in synchronous mode, the selected clock is simply
divided by the field CD in US_BRGR.
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
BaudRate = SelectedClock
-------------------------------------CD
In synchronous mode, if the external clock is selected (USCLKS = 3), the clock is provided
directly by the signal on the USART SCK pin. No division is active. The value written in
US_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 SCK or the internal clock divided (MCK/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
SCK pin. If the internal clock MCK is selected, the Baud Rate Generator ensures a 50:50 duty
cycle on the SCK pin, even if the value programmed in CD is odd.
30.6.1.3
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 30-3.
Table 30-3.
Binary and Decimal Values for D
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 30-4.
Table 30-4.
Binary and Decimal Values for F
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 30-5 shows the resulting Fi/Di Ratio, which is the ratio between the ISO7816 clock and the
baud rate clock.
Table 30-5.
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
417
1768I–ATARM–09-Jul-09
Table 30-5.
Possible Values for the Fi/Di Ratio (Continued)
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 (US_MR) is first divided by the value programmed in the field CD in the Baud
Rate Generator Register (US_BRGR). The resulting clock can be provided to the SCK pin to
feed the smart card clock inputs. This means that the CLKO bit can be set in US_MR.
This clock is then divided by the value programmed in the FI_DI_RATIO field in the FI_DI_Ratio
register (US_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 30-4 shows the relation between the Elementary Time Unit, corresponding to a bit time,
and the ISO 7816 clock.
Figure 30-4. Elementary Time Unit (ETU)
FI_DI_RATIO
ISO7816 Clock Cycles
ISO7816 Clock
on SCK
ISO7816 I/O Line
on TXD
1 ETU
30.6.2
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 (US_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 (US_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
(US_CR). The reset commands have the same effect as a hardware reset on the corresponding
logic. 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 US_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
418
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
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 (US_THR). If
a time guard is programmed, it is handled normally.
30.6.3
30.6.3.1
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 MODE9 bit in the Mode Register
(US_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 US_MR. The even, odd, space, marked or none
parity bit can be configured. The MSBF field in US_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 US_MR. The 1.5 stop bit is supported in
asynchronous mode only.
Figure 30-5. 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 (US_THR). The transmitter
reports two status bits in the Channel Status Register (US_CSR): TXRDY (Transmitter Ready),
which indicates that US_THR is empty and TXEMPTY, which indicates that all the characters
written in US_THR have been processed. When the current character processing is completed,
the last character written in US_THR is transferred into the Shift Register of the transmitter and
US_THR becomes empty, thus TXRDY raises.
Both TXRDY and TXEMPTY bits are low since the transmitter is disabled. Writing a character in
US_THR while TXRDY is active has no effect and the written character is lost.
419
1768I–ATARM–09-Jul-09
Figure 30-6. 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
US_THR
TXRDY
TXEMPTY
30.6.3.2
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 (US_MR).
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. 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 30-7 and Figure 30-8 illustrate start detection and character reception when USART
operates in asynchronous mode.
420
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Figure 30-7. 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 30-8. 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
30.6.3.3
D1
D2
D3
D4
D5
D6
D7
Parity
Bit
Stop
Bit
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 30-9 illustrates a character reception in synchronous mode.
421
1768I–ATARM–09-Jul-09
Figure 30-9. 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
30.6.3.4
Receiver Operations
When a character reception is completed, it is transferred to the Receive Holding Register
(US_RHR) and the RXRDY bit in the Status Register (US_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 US_RHR and overwrites the previous one. The OVRE bit is cleared by writing
the Control Register (US_CR) with the RSTSTA (Reset Status) bit at 1.
Figure 30-10. 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
US_CR
Read
US_RHR
RXRDY
OVRE
30.6.3.5
Parity
The USART supports five parity modes selected by programming the PAR field in the Mode
Register (US_MR). The PAR field also enables the Multi-drop Mode, see “Multi-drop Mode” on
page 423. 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
422
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
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 30-6 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. I
Table 30-6.
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 (US_CSR). The PARE bit can be cleared by writing the Control Register (US_CR) with
the RSTSTA bit at 1. Figure 30-11 illustrates the parity bit status setting and clearing.
Figure 30-11. Parity Error
Baud Rate
Clock
RXD
Start
D0
Bit
D1
D2
D3
D4
D5
D6
D7
Bad Stop
Parity Bit
Bit
RSTSTA = 1
Write
US_CR
PARE
RXRDY
30.6.3.6
Multi-drop Mode
If the PAR field in the Mode Register (US_MR) is programmed to the value 0x6 or 0x7, the
USART runs in Multi-drop 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 multi-drop 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.
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1768I–ATARM–09-Jul-09
The transmitter sends an address byte (parity bit set) when SENDA is written to US_CR. In this
case, the next byte written to US_THR is transmitted as an address. Any character written in
US_THR without having written the command SENDA is transmitted normally with the parity at
0.
30.6.3.7
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 (US_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 30-12, 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
US_THR. TXEMPTY remains low until the timeguard transmission is completed as the timeguard is part of the current character being transmitted.
Figure 30-12. 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
US_THR
TXRDY
TXEMPTY
Table 30-7 indicates the maximum length of a timeguard period that the transmitter can handle
in relation to the function of the Baud Rate.
Table 30-7.
424
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
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table 30-7.
30.6.3.8
Maximum Timeguard Length Depending on Baud Rate (Continued)
Baud Rate
Bit time
Timeguard
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 (US_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 (US_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 US_CSR
remains at 0. Otherwise, the receiver loads a 16-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.
The user can either:
• Obtain an interrupt when a time-out is detected after having received at least one character.
This is performed by writing the Control Register (US_CR) with the STTTO (Start Time-out)
bit at 1.
• Obtain a periodic interrupt while no character is received. This is performed by writing
US_CR with the RETTO (Reload and Start Time-out) bit at 1.
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 30-13 shows the block diagram of the Receiver Time out feature.
Figure 30-13. Receiver Time-out Block Diagram
TO
Baud Rate
Clock
1
D
Q
Clock
16-bit Time-out
Counter
16-bit
Value
=
STTTO
Character
Received
Clear
Load
TIMEOUT
0
RETTO
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1768I–ATARM–09-Jul-09
Table 30-8 gives the maximum time-out period for some standard baud rates.t
Table 30-8.
30.6.3.9
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
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 (US_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 (US_CR) with the RSTSTA bit at 1.
Figure 30-14. Framing Error Status
Baud Rate
Clock
RXD
Start
D0
Bit
D1
D2
D3
D4
D5
D6
D7
Parity Stop
Bit Bit
RSTSTA = 1
Write
US_CR
FRAME
RXRDY
30.6.3.10
426
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
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
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 (US_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 US_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 US_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.
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 US_CSR is at 1 and the start of the
break condition clears the TXRDY and TXEMPTY bits as if a character is processed.
Writing US_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 30-15 illustrates the effect of both the Start Break (STTBRK) and Stop Break (STP BRK)
commands on the TXD line.
Figure 30-15. 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
US_CR
TXRDY
TXEMPTY
30.6.3.11
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.
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1768I–ATARM–09-Jul-09
When the low stop bit is detected, the receiver asserts the RXBRK bit in US_CSR. This bit may
be cleared by writing the Control Register (US_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.
30.6.3.12
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 30-16.
Figure 30-16. 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
USART_MODE field in the Mode Register (US_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 PDC channel for reception. The transmitter
can handle hardware handshaking in any case.
Figure 30-17 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 PDC 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 PDC clears the
status bit RXBUFF and, as a result, asserts the pin RTS low.
Figure 30-17. Receiver Behavior when Operating with Hardware Handshaking
RXD
RXEN = 1
RXDIS = 1
Write
US_CR
RTS
RXBUFF
Figure 30-18 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.
428
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AT91RM9200
Figure 30-18. Transmitter Behavior when Operating with Hardware Handshaking
CTS
TXD
30.6.4
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 USART_MODE field in the
Mode Register (US_MR) to the value 0x4 for protocol T = 0 and to the value 0x5 for protocol T =
1.
30.6.4.1
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 415).
The USART connects to a smart card. as shown in Figure 30-19. The TXD line becomes bidirectional and the Baud Rate Generator feeds the ISO7816 clock on the SCK 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 30-19. Connection of a Smart Card to the USART
USART
SCK
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.
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 (US_THR) or after reading it in the Receive Holding Register (US_RHR).
429
1768I–ATARM–09-Jul-09
30.6.4.2
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 30-20.
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 30-21. 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 (US_RHR). It appropriately sets the PARE bit in the Status Register (US_SR) so that the software can handle the error.
Figure 30-20. 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 30-21. 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
Receive Error Counter
The USART receiver also records the total number of errors. This can be read in the Number of
Error (US_NER) register. The NB_ERRORS field can record up to 255 errors. Reading US_NER
automatically clears the NB_ERRORS field.
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 (US_MR). If INACK is at 1, no error signal is driven on the I/O
line even if a parity bit is detected, but the INACK bit is set in the Status Register (US_SR). The
INACK bit can be cleared by writing the Control Register (US_CR) with the RSTNACK bit at 1.
Moreover, if INACK is reset, the erroneous received character is stored in the Receive Holding
Register, as if no error occurred. However, the RXRDY bit does not raise.
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
430
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
MAX_ITERATION field in the Mode Register (US_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 (US_CSR). If the repetition of the character is acknowledged by the
receiver, the repetitions are stopped and the iteration counter is cleared.
The ITERATION bit in US_CSR can be cleared by writing the Control Register with the RSIT bit
at 1.
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 (US_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.
30.6.4.3
30.6.5
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 (US_CSR).
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 30-22. The modulator and demodulator are compliant
with the IrDA specification version 1.1 and support data transfer speeds ranging from 2,4 Kbps
to 115,2 Kbps.
The USART IrDA mode is enabled by setting the USART_MODE field in the Mode Register
(US_MR) to the value 0x8. The IrDA Filter Register (US_IF) allows configuring the demodulator
filter. The USART transmitter and receiver operate in a normal asynchronous mode and all
parameters are accessible. Note that the modulator and the demodulator are activated.
Figure 30-22. Connection to IrDA Transceivers
USART
IrDA
Transceivers
Receiver
Demodulator
RXD
Transmitter
Modulator
TXD
RX
TX
431
1768I–ATARM–09-Jul-09
The receiver and the transmitter must be enabled or disabled according to the direction of the
transmission to be managed.
30.6.5.1
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 30-9.
Table 30-9.
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 30-23 shows an example of character transmission.
Figure 30-23. IrDA Modulation
Start
Bit
Transmitter
Output
0
Start
Bit
Data Bits
0
1
1
0
0
1
1
0
1
TXD
3
16 Bit Period
Bit Period
30.6.5.2
IrDA Baud Rate
Table 30-10 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 30-10. IrDA Baud Rate Error
432
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
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table 30-10. IrDA Baud Rate Error
30.6.5.3
Peripheral Clock
Baud rate
CD
Baud rate Error
Pulse time
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
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 US_IF. When a falling edge is detected on the RXD pin,
the Filter Counter starts counting down at the Master Clock (MCK) speed. If a rising edge is
detected on the RXD pin, the counter stops and is reloaded with US_IF. If no rising edge is
detected when the counter reaches 0, the input of the receiver is driven low during one bit time.
Figure 30-24 illustrates the operations of the IrDA demodulator.
Figure 30-24. IrDA Demodulator Operations
MCK
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
US_FIDI must be set to a value higher than 0 in order to assure IrDA communications operate
correctly.
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1768I–ATARM–09-Jul-09
30.6.6
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 are 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 an RS485 bus is shown in Figure 30-25.
Figure 30-25. Typical Connection to an RS485 bus.
USART
RXD
Differential
Bus
TXD
RTS
The USART is set in RS485 mode by programming the USART_MODE field in the Mode Register (US_MR) to the value 0x1.
The RTS pin is at a level inverse of 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 30-26 gives an example of the RTS waveform during a character transmission
when the timeguard is enabled.
Figure 30-26. 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
US_THR
TXRDY
TXEMPTY
RTS
30.6.7
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
434
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1768I–ATARM–09-Jul-09
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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 USART_MODE field in the Mode
Register (US_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 30-11 gives the correspondence of the USART signals with modem connection standards.
Table 30-11. 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 RTS and DTR output pins is performed by witting the Control Register
(US_CR) with the RTSDIS, RTSEN, DTRDIS and DTREN bits respectively at 1. The disable
command forces the corresponding pin to its inactive level, i.e. high. The enable commands
force the corresponding pin to its active level, i.e. low.
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 (US_CSR)
are set respectively and can trigger an interrupt. The status is automatically cleared when
US_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.
30.6.8
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.
30.6.8.1
Normal Mode
As a reminder, the normal mode simply connects the RXD pin on the receiver input and the
transmitter output on the TXD pin.
Figure 30-27. Normal Mode Configuration
RXD
Receiver
TXD
Transmitter
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1768I–ATARM–09-Jul-09
30.6.8.2
Automatic Echo
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 30-28. 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 30-28. Automatic Echo
RXD
Receiver
TXD
Transmitter
30.6.8.3
Local Loopback
The local loopback mode connects the output of the transmitter directly to the input of the
receiver, as shown in Figure 30-29. 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 30-29. Local Loopback
RXD
Receiver
1
Transmitter
30.6.8.4
TXD
Remote Loopback
Remote loopback mode directly connects the RXD pin to the TXD pin, as shown in Figure 30-30.
The transmitter and the receiver are disabled and have no effect. This mode allows bit-by-bit
retransmission.
Figure 30-30. Remote Loopback
Receiver
1
RXD
TXD
Transmitter
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1768I–ATARM–09-Jul-09
AT91RM9200
30.7
USART User Interface
Table 30-12.
USART Memory Map
Offset
Register
Name
Access
Reset State
0x0000
Control Register
US_CR
Write-only
–
0x0004
Mode Register
US_MR
Read/Write
–
0x0008
Interrupt Enable Register
US_IER
Write-only
–
0x000C
Interrupt Disable Register
US_IDR
Write-only
–
0x0010
Interrupt Mask Register
US_IMR
Read-only
0x0
0x0014
Channel Status Register
US_CSR
Read-only
–
0x0018
Receiver Holding Register
US_RHR
Read-only
0x0
0x001C
Transmitter Holding Register
US_THR
Write-only
–
0x0020
Baud Rate Generator Register
US_BRGR
Read/Write
0x0
0x0024
Receiver Time-out Register
US_RTOR
Read/Write
0x0
0x0028
Transmitter Timeguard Register
US_TTGR
Read/Write
0x0
–
–
–
0x2C
to
0x3C
Reserved
0x0040
FI DI Ratio Register
US_FIDI
Read/Write
0x174
0x0044
Number of Errors Register
US_NER
Read-only
–
0x0048
Reserved
–
–
–
0x004C
IrDA Filter Register
US_IF
Read/Write
0x0
0x5C
to
0xFC
Reserved
–
–
–
0x100
to
0x128
Reserved for PDC Registers
–
–
–
437
1768I–ATARM–09-Jul-09
30.7.1
Name:
USART Control Register
US_CR
Access Type:
Write-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
RTSDIS
18
RTSEN
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
–
• RSTRX: Reset Receiver
0 = No effect.
1 = Resets the receiver.
• RSTTX: Reset Transmitter
0 = No effect.
1 = Resets the transmitter.
• RXEN: Receiver Enable
0 = No effect.
1 = Enables the receiver, if RXDIS is 0.
• RXDIS: Receiver Disable
0 = No effect.
1 = Disables the receiver.
• TXEN: Transmitter Enable
0 = No effect.
1 = Enables the transmitter if TXDIS is 0.
• TXDIS: Transmitter Disable
0 = No effect.
1 = Disables the transmitter.
• RSTSTA: Reset Status Bits
0 = No effect.
1 = Resets the status bits PARE, FRAME, OVRE and RXBRK in the US_CSR.
• STTBRK: Start Break
438
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
0 = No effect.
1 = Starts transmission of a break after the characters present in US_THR and the Transmit Shift Register have been
transmitted. No effect if a break is already being transmitted.
• 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.
• STTTO: Start Time-out
0 = No effect
1 = Starts waiting for a character before clocking the time-out counter.
• SENDA: Send Address
0 = No effect.
1 = In Multi-drop Mode only, the next character written to the US_THR is sent with the address bit set.
• RSTIT: Reset Iterations
0 = No effect.
1 = Resets ITERATION in US_CSR. No effect if the ISO7816 is not enabled.
• RSTNACK: Reset Non Acknowledge
0 = No effect
1 = Resets NACK in US_CSR.
• RETTO: Rearm Time-out
0 = No effect
1 = Restart Time-out
• DTREN: Data Terminal Ready Enable
0 = No effect.
1 = Drives the pin DTR at 0.
• DTRDIS: Data Terminal Ready Disable
0 = No effect.
1 = Drives the pin DTR to 1.
• RTSEN: Request to Send Enable
0 = No effect.
1 = Drives the pin RTS to 0.
• RTSDIS: Request to Send Disable
0 = No effect.
439
1768I–ATARM–09-Jul-09
1 = Drives the pin RTS to 1.
440
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
30.7.2
Name:
USART Mode Register
US_MR
Access Type:
Read/Write
31
–
30
–
29
–
28
FILTER
27
–
26
25
MAX_ITERATION
24
23
–
22
–
21
DSNACK
20
INACK
19
OVER
18
CLKO
17
MODE9
16
MSBF
15
14
13
12
11
10
PAR
9
8
SYNC
4
3
2
1
0
CHMODE
7
NBSTOP
6
5
CHRL
USCLKS
USART_MODE
• USART_MODE
USART_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
0
1
Reserved
0
1
1
0
IS07816 Protocol: T = 1
0
1
1
1
Reserved
1
0
0
0
IrDA
1
1
x
x
Reserved
• USCLKS: Clock Selection
USCLKS
Selected Clock
0
0
MCK
0
1
MCK / DIV
1
0
Reserved
1
1
SCK
441
1768I–ATARM–09-Jul-09
• CHRL: Character Length.
CHRL
Character Length
0
0
5 bits
0
1
6 bits
1
0
7 bits
1
1
8 bits
• SYNC: Synchronous Mode Select
0 = USART operates in Asynchronous Mode.
1 = USART operates in Synchronous Mode
• PAR: Parity Type
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
Multi-drop mode
• NBSTOP: Number of Stop Bits
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
• CHMODE: Channel Mode
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.
• MSBF: Bit Order
0 = Least Significant Bit is sent/received first.
1 = Most Significant Bit is sent/received first.
442
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
• MODE9: 9-bit Character Length
0 = CHRL defines character length.
1 = 9-bit character length.
• CKLO: Clock Output Select
0 = The USART does not drive the SCK pin.
1 = The USART drives the SCK pin if USCLKS does not select the external clock SCK.
• OVER: Oversampling Mode
0 = 16x Oversampling.
1 = 8x Oversampling.
• INACK: Inhibit Non Acknowledge
0 = The NACK is generated.
1 = The NACK is not generated.
• 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.
• MAX_ITERATION
Defines the maximum number of iterations in mode ISO7816, protocol T = 0.
• 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).
443
1768I–ATARM–09-Jul-09
30.7.3
Name:
USART Interrupt Enable Register
US_IER
Access Type:
Write-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
CTSIC
18
DCDIC
17
DSRIC
16
RIIC
15
–
14
–
13
NACK
12
RXBUFF
11
TXBUFE
10
ITERATION
9
TXEMPTY
8
TIMEOUT
7
PARE
6
FRAME
5
OVRE
4
ENDTX
3
ENDRX
2
RXBRK
1
TXRDY
0
RXRDY
• RXRDY: RXRDY Interrupt Enable
• TXRDY: TXRDY Interrupt Enable
• RXBRK: Receiver Break Interrupt Enable
• ENDRX: End of Receive Transfer Interrupt Enable
• ENDTX: End of Transmit Interrupt Enable
• OVRE: Overrun Error Interrupt Enable
• FRAME: Framing Error Interrupt Enable
• PARE: Parity Error Interrupt Enable
• TIMEOUT: Time-out Interrupt Enable
• TXEMPTY: TXEMPTY Interrupt Enable
• ITERATION: Iteration Interrupt Enable
• TXBUFE: Buffer Empty Interrupt Enable
• RXBUFF: Buffer Full Interrupt Enable
• NACK: Non Acknowledge Interrupt Enable
• RIIC: Ring Indicator Input Change Enable
• DSRIC: Data Set Ready Input Change Enable
• DCDIC: Data Carrier Detect Input Change Interrupt Enable
• CTSIC: Clear to Send Input Change Interrupt Enable
0 = No effect.
1 = Enables the corresponding interrupt.
444
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
30.7.4
Name:
USART Interrupt Disable Register
US_IDR
Access Type:
Write-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
CTSIC
18
DCDIC
17
DSRIC
16
RIIC
15
–
14
–
13
NACK
12
RXBUFF
11
TXBUFE
10
ITERATION
9
TXEMPTY
8
TIMEOUT
7
PARE
6
FRAME
5
OVRE
4
ENDTX
3
ENDRX
2
RXBRK
1
TXRDY
0
RXRDY
• RXRDY: RXRDY Interrupt Disable
• TXRDY: TXRDY Interrupt Disable
• RXBRK: Receiver Break Interrupt Disable
• ENDRX: End of Receive Transfer Interrupt Disable
• ENDTX: End of Transmit Interrupt Disable
• OVRE: Overrun Error Interrupt Disable
• FRAME: Framing Error Interrupt Disable
• PARE: Parity Error Interrupt Disable
• TIMEOUT: Time-out Interrupt Disable
• TXEMPTY: TXEMPTY Interrupt Disable
• ITERATION: Iteration Interrupt Disable
• TXBUFE: Buffer Empty Interrupt Disable
• RXBUFF: Buffer Full Interrupt Disable
• NACK: Non Acknowledge Interrupt Disable
• RIIC: Ring Indicator Input Change Disable
• DSRIC: Data Set Ready Input Change Disable
• DCDIC: Data Carrier Detect Input Change Interrupt Disable
• CTSIC: Clear to Send Input Change Interrupt Disable
0 = No effect.
1 = Disables the corresponding interrupt.
445
1768I–ATARM–09-Jul-09
30.7.5
Name:
USART Interrupt Mask Register
US_IMR
Access Type:
Read-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
CTSIC
18
DCDIC
17
DSRIC
16
RIIC
15
–
14
–
13
NACK
12
RXBUFF
11
TXBUFE
10
ITERATION
9
TXEMPTY
8
TIMEOUT
7
PARE
6
FRAME
5
OVRE
4
ENDTX
3
ENDRX
2
RXBRK
1
TXRDY
0
RXRDY
• RXRDY: RXRDY Interrupt Mask
• TXRDY: TXRDY Interrupt Mask
• RXBRK: Receiver Break Interrupt Mask
• ENDRX: End of Receive Transfer Interrupt Mask
• ENDTX: End of Transmit Interrupt Mask
• OVRE: Overrun Error Interrupt Mask
• FRAME: Framing Error Interrupt Mask
• PARE: Parity Error Interrupt Mask
• TIMEOUT: Time-out Interrupt Mask
• TXEMPTY: TXEMPTY Interrupt Mask
• ITERATION: Iteration Interrupt Mask
• TXBUFE: Buffer Empty Interrupt Mask
• RXBUFF: Buffer Full Interrupt Mask
• NACK: Non Acknowledge Interrupt Mask
• RIIC: Ring Indicator Input Change Mask
• DSRIC: Data Set Ready Input Change Mask
• DCDIC: Data Carrier Detect Input Change Interrupt Mask
• CTSIC: Clear to Send Input Change Interrupt Mask
0 = The corresponding interrupt is disabled.
1 = The corresponding interrupt is enabled.
446
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
30.7.6
Name:
USART Channel Status Register
US_CSR
Access Type:
Read-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
CTS
22
DCD
21
DSR
20
RI
19
CTSIC
18
DCDIC
17
DSRIC
16
RIIC
15
–
14
–
13
NACK
12
RXBUFF
11
TXBUFE
10
ITERATION
9
TXEMPTY
8
TIMEOUT
7
PARE
6
FRAME
5
OVRE
4
ENDTX
3
ENDRX
2
RXBRK
1
TXRDY
0
RXRDY
• RXRDY: Receiver Ready
0 = No complete character has been received since the last read of US_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 US_RHR has not yet been read.
• TXRDY: Transmitter Ready
0 = A character is in the US_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 US_THR.
• 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.
• ENDRX: End of Receiver Transfer
0 = The End of Transfer signal from the Receive PDC channel is inactive.
1 = The End of Transfer signal from the Receive PDC channel is active.
• ENDTX: End of Transmitter Transfer
0 = The End of Transfer signal from the Transmit PDC channel is inactive.
1 = The End of Transfer signal from the Transmit PDC channel is active.
• 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.
• 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.
447
1768I–ATARM–09-Jul-09
• 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.
• TIMEOUT: Receiver Time-out
0 = There has not been a time-out since the last Start Time-out command or the Time-out Register is 0.
1 = There has been a time-out since the last Start Time-out command.
• TXEMPTY: Transmitter Empty
0 = There are characters in either US_THR or the Transmit Shift Register, or the transmitter is disabled.
1 = There is at least one character in either US_THR or the Transmit Shift Register.
• ITERATION: Max number of Repetitions Reached
0 = Maximum number of repetitions has not been reached since the last RSIT.
1 = Maximum number of repetitions has been reached since the last RSIT.
• TXBUFE: Transmission Buffer Empty
0 = The signal Buffer Empty from the Transmit PDC channel is inactive.
1 = The signal Buffer Empty from the Transmit PDC channel is active.
• RXBUFF: Reception Buffer Full
0 = The signal Buffer Full from the Receive PDC channel is inactive.
1 = The signal Buffer Full from the Receive PDC channel is active.
• NACK: Non Acknowledge
0 = No Non Acknowledge has not been detected since the last RSTNACK.
1 = At least one Non Acknowledge has been detected since the last RSTNACK.
• RIIC: Ring Indicator Input Change Flag
0 = No input change has been detected on the RI pin since the last read of US_CSR.
1 = At least one input change has been detected on the RI pin since the last read of US_CSR.
• DSRIC: Data Set Ready Input Change Flag
0 = No input change has been detected on the DSR pin since the last read of US_CSR.
1 = At least one input change has been detected on the DSR pin since the last read of US_CSR.
• DCDIC: Data Carrier Detect Input Change Flag
0 = No input change has been detected on the DCD pin since the last read of US_CSR.
1 = At least one input change has been detected on the DCD pin since the last read of US_CSR.
• CTSIC: Clear to Send Input Change Flag
0 = No input change has been detected on the CTS pin since the last read of US_CSR.
1 = At least one input change has been detected on the CTS pin since the last read of US_CSR.
• RI: Image of RI Input
448
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
0 = RI is at 0.
1 = RI is at 1.
• DSR: Image of DSR Input
0 = DSR is at 0
1 = DSR is at 1.
• DCD: Image of DCD Input
0 = DCD is at 0.
1 = DCD is at 1.
• CTS: Image of CTS Input
0 = CTS is at 0.
1 = CTS is at 1.
449
1768I–ATARM–09-Jul-09
30.7.7
Name:
USART Receive Holding Register
US_RHR
Access Type:
Read-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
–
14
–
13
–
12
–
11
–
10
–
9
–
8
RXCHR
7
6
5
4
3
2
1
0
RXCHR
• RXCHR: Received Character
Last character received if RXRDY is set.
30.7.8
Name:
USART Transmit Holding Register
US_THR
Access Type:
Write-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
–
14
–
13
–
12
–
11
–
10
–
9
–
8
TXCHR
7
6
5
4
3
2
1
0
TXCHR
• TXCHR: Character to be Transmitted
Next character to be transmitted after the current character if TXRDY is not set.
450
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
30.7.9
Name:
USART Baud Rate Generator Register
US_BRGR
Access Type:
Read/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
3
2
1
0
CD
7
6
5
4
CD
• CD: Clock Divider
USART_MODE ≠ ISO7816
SYNC = 0
CD
OVER = 0
OVER = 1
0
1 to 65535
30.7.10
Name:
USART_MODE =
ISO7816
SYNC = 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
USART Receiver Time-out Register
US_RTOR
Access Type:
Read/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
3
2
1
0
TO
7
6
5
4
TO
• TO: Time-out Value
0: The Receiver Time-out is disabled.
1 - 65535: The Receiver Time-out is enabled and the Time-out delay is TO x Bit Period.
451
1768I–ATARM–09-Jul-09
30.7.11
Name:
USART Transmitter Timeguard Register
US_TTGR
Access Type:
Read/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
TG
• 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.
30.7.12
Name:
USART FI DI RATIO Register
US_FIDI
Access Type:
Read/Write
Reset Value :
0x174
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
• 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 SCK divided by FI_DI_RATIO.
452
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
30.7.13
Name:
USART Number of Errors Register
US_NER
Access Type:
Read-only
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.
30.7.14
Name:
USART IrDA FILTER Register
US_IF
Access Type:
Read/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
IRDA_FILTER
• IRDA_FILTER: IrDA Filter
Sets the filter of the IrDA demodulator.
453
1768I–ATARM–09-Jul-09
454
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
31. Serial Synchronous Controller (SSC)
31.1
Overview
The Atmel 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 contains an independent receiver and transmitter and a common clock divider. The
receiver and the transmitter each interface with three signals: the TD/RD signal for data, the
TK/RK signal for the clock and the TF/RF signal for the Frame Sync. Transfers contain up to 16
data of up to 32 bits. they 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 PDC channels of up to 32 bits
permit a continuous high bit rate data transfer without processor intervention.
Featuring connection to two PDC channels, the SSC permits interfacing with low processor
overhead to the following:
• CODECs in master or slave mode
• DAC through dedicated serial interface, particularly I2S
• Magnetic card reader
Features of the SSC are:
• Provides Serial Synchronous Communication Links Used in Audio and Telecom Applications
• Contains an Independent Receiver and Transmitter and a Common Clock Divider
• Interfaced with Two PDC Channels (DMA Access) to Reduce Processor Overhead
• Offers a Configurable Frame Sync and Data Length
• Receiver and Transmitter can be Programmed to Start Automatically or on Detection of
Different Event on the Frame Sync Signal
• Receiver and Transmitter Include a Data Signal, a Clock Signal and a Frame Synchronization
Signal
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1768I–ATARM–09-Jul-09
31.2
Block Diagram
Figure 31-1. Block Diagram
ASB
APB Bridge
PDC
APB
TF
TK
PMC
TD
MCK
PIO
SSC Interface
RF
RK
Interrupt Control
RD
SSC Interrupt
31.3
Application Block Diagram
Figure 31-2. Application Block Diagram
OS or RTOS Driver
Power
Management
Interrupt
Management
Test
Management
SSC
Serial AUDIO
456
Codec
Time Slot
Management
Frame
Management
Line Interface
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
31.4
Pin Name List
Table 31-1.
31.5
31.5.1
I/O Lines Description
Pin Name
Pin Description
Type
RF
Receiver Frame Synchro
Input/Output
RK
Receiver Clock
Input/Output
RD
Receiver Data
Input
TF
Transmitter Frame Synchro
Input/Output
TK
Transmitter Clock
Input/Output
TD
Transmitter Data
Output
Product Dependencies
I/O Lines
The pins used for interfacing the compliant external devices may be multiplexed with PIO lines.
Before using the SSC receiver, the PIO controller must be configured to dedicate the SSC
receiver I/O lines to the SSC peripheral mode.
Before using the SSC transmitter, the PIO controller must be configured to dedicate the SSC
transmitter I/O lines to the SSC peripheral mode.
31.5.2
Power Management
The SSC is not continuously clocked. The SSC interface may be clocked through the Power
Management Controller (PMC), therefore the programmer must first configure the PMC to
enable the SSC clock.
31.5.3
Interrupt
The SSC interface has an interrupt line connected to the Advanced Interrupt Controller (AIC).
Handling interrupts requires programming the AIC before configuring the SSC.
All SSC interrupts can be enabled/disabled configuring the SSC Interrupt mask register. Each
pending and unmasked SSC interrupt will assert the SSC interrupt line. The SSC interrupt service routine can get the interrupt origin by reading the SSC interrupt status register.
31.6
Functional Description
This chapter contains the functional description of the following: SSC Functional Block, Clock
Management, Data format, Start, Transmitter, Receiver and Frame Sync.
The receiver and 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 TK or RK pins. This allows the
SSC to support many slave-mode data transfers. The maximum clock speed allowed on the TK
and RK pins is the master clock divided by 2. Each level of the clock must be stable for at least
two master clock periods.
457
1768I–ATARM–09-Jul-09
Figure 31-3. SSC Functional Block Diagram
Transmitter
MCK
TK Input
Clock
Divider
Transmit Clock
Controller
RX clock
TF
RF
Start
Selector
TX clock
Clock Output
Controller
TK
Frame Sync
Controller
TF
Transmit Shift Register
TX PDC
APB
Transmit Holding
Register
TD
Transmit Sync
Holding Register
Load Shift
User
Interface
Receiver
RK Input
Receive Clock RX Clock
Controller
TX Clock
RF
TF
Start
Selector
Interrupt Control
RK
Frame Sync
Controller
RF
Receive Shift Register
RX PDC
PDC
Clock Output
Controller
Receive Holding
Register
RD
Receive Sync
Holding Register
Load Shift
AIC
31.6.1
Clock Management
The transmitter clock can be generated by:
• an external clock received on the TK I/O pad
• the receiver clock
• the internal clock divider
The receiver clock can be generated by:
• an external clock received on the RK I/O pad
• the transmitter clock
• the internal clock divider
Furthermore, the transmitter block can generate an external clock on the TK I/O pad, and the
receiver block can generate an external clock on the RK I/O pad.
This allows the SSC to support many Master and Slave-mode data transfers.
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31.6.1.1
Clock Divider
Figure 31-4. Divided Clock Block Diagram
Clock Divider
SSC_CMR
MCK
12-bit Counter
/2
Divided Clock
The Master Clock divider is determined by the 12-bit field DIV counter and comparator (so its
maximal value is 4095) in the Clock Mode Register SSC_CMR, allowing a Master Clock division
by up to 8190. The Divided Clock is provided to both the Receiver and Transmitter. When this
field is programmed to 0, the Clock Divider is not used and remains inactive.
When DIV is set to a value equal or greater to 1, the Divided Clock has a frequency of Master
Clock divided by 2 times DIV. Each level of the Divided Clock has a duration of the Master Clock
multiplied by DIV. This ensures a 50% duty cycle for the Divided Clock regardless if the DIV
value is even or odd.
Figure 31-5.
Divided Clock Generation
Master Clock
Divided Clock
DIV = 1
Divided Clock Frequency = MCK/2
Master Clock
Divided Clock
DIV = 3
Divided Clock Frequency = MCK/6
Table 31-2.
31.6.1.2
Bit Rate
Maximum
Minimum
MCK / 2
MCK / 8190
Transmitter Clock Management
The transmitter clock is generated from the receiver clock or the divider clock or an external
clock scanned on the TK I/O pad. The transmitter clock is selected by the CKS field in
SSC_TCMR (Transmit Clock Mode Register). Transmit Clock can be inverted independently by
the CKI bits in SSC_TCMR.
The transmitter can also drive the TK I/O pad continuously or be limited to the actual data transfer. The clock output is configured by the SSC_TCMR register. The Transmit Clock Inversion
(CKI) bits have no effect on the clock outputs. Programming the TCMR register to select TK pin
459
1768I–ATARM–09-Jul-09
(CKS field) and at the same time Continuous Transmit Clock (CKO field) might lead to unpredictable results.
Figure 31-6. Transmitter Clock Management
SSC_TCMR.CKS
SSC_TCMR.CKO
TK
Receiver Clock
TK
Divider Clock
Transmitter Clock
0
1
SSC_TCMR.CKI
31.6.1.3
Receiver Clock Management
The receiver clock is generated from the transmitter clock or the divider clock or an external
clock scanned on the RK I/O pad. The Receive Clock is selected by the CKS field in
SSC_RCMR (Receive Clock Mode Register). Receive Clocks can be inverted independently by
the CKI bits in SSC_RCMR.
The receiver can also drive the RK I/O pad continuously or be limited to the actual data transfer.
The clock output is configured by the SSC_RCMR register. The Receive Clock Inversion (CKI)
bits have no effect on the clock outputs. Programming the RCMR register to select RK pin (CKS
field) and at the same time Continuous Receive Clock (CKO field) might lead to unpredictable
results.
Figure 31-7. Receiver Clock Management
SSC_RCMR.CKS
SSC_RCMR.CKO
RK
Transmitter Clock
RK
Divider Clock
0
Receiver Clock
1
SSC_RCMR.CKI
31.6.2
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 setting the Transmit Clock Mode Register (SSC_TCMR). (See
Section 31.6.4 ”Start” on page 462.)
The frame synchronization is configured setting the Transmit Frame Mode Register
(SSC_TFMR). (See Section 31.6.5 ”Frame Sync” on page 463.)
To transmit data, the transmitter uses a shift register clocked by the transmitter clock signal and
the start mode selected in the SSC_TCMR. Data is written by the application to the SSC_THR
register then transferred to the shift register according to the data format selected.
When both the SSC_THR and the transmit shift register are empty, the status flag TXEMPTY is
set in SSC_SR. When the Transmit Holding register is transferred in the Transmit shift register,
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AT91RM9200
the status flag TXRDY is set in SSC_SR and additional data can be loaded in the holding
register.
Figure 31-8. Transmitter Block Diagram
SSC_CR.TXEN
SSC_SR.TXEN
SSC_CR.TXDIS
SSC_TFMR.DATDEF
1
RF
Transmitter Clock
TF
Start
Selector
31.6.3
TD
0
SSC_TFMR.MSBF
Transmit Shift Register
SSC_TFMR.FSDEN
SSC_TCMR.STTDLY
SSC_TFMR.DATLEN
SSC_TCMR.STTDLY
SSC_TFMR.FSDEN
SSC_TFMR.DATNB
0
SSC_THR
1
SSC_TSHR
SSC_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 setting the Receive Clock Mode Register (SSC_RCMR). (See Section 31.6.4 ”Start” on page 462.)
The frame synchronization is configured setting the Receive Frame Mode Register
(SSC_RFMR). (See Section 31.6.5 ”Frame Sync” on page 463.)
The receiver uses a shift register clocked by the receiver clock signal and the start mode
selected in the SSC_RCMR. The data is transferred from the shift register in function of data format selected.
When the receiver shift register is full, the SSC transfers this data in the holding register, the status flag RXRDY is set in SSC_SR and the data can be read in the receiver holding register, if
another transfer occurs before read the RHR register, the status flag OVERUN is set in SSC_SR
and the receiver shift register is transferred in the RHR register.
461
1768I–ATARM–09-Jul-09
Figure 31-9. Receiver Block Diagram
SSC_CR.RXEN
SSC_SR.RXEN
SSC_CR.RXDIS
RF
Receiver Clock
TF
SSC_RFMR.MSBF
Start
Selector
SSC_RFMR.DATNB
Receive Shift Register
SSC_RSHR
SSC_RHR
SSC_RFMR.FSLEN
SSC_RFMR.DATLEN
RD
SSC_RCMR.STTDLY
31.6.4
Start
The transmitter and receiver can both be programmed to start their operations when an event
occurs, respectively in the Transmit Start Selection (START) field of SSC_TCMR and in the
Receive Start Selection (START) field of SSC_RCMR.
Under the following conditions the start event is independently programmable:
• Continuous. In this case, the transmission starts as soon as a word is written in SSC_THR
and the reception starts as soon as the Receiver is enabled.
• Synchronously with the transmitter/receiver
• On detection of a falling/rising edge on TK/RK
• On detection of a low level/high level on TK/RK
• On detection of a level change or an edge on TK/RK
A start can be programmed in the same manner on either side of the Transmit/Receive Clock
Register (RCMR/TCMR). Thus, the start could be on TF (Transmit) or RF (Receive).
Detection on TF/RF input/output is done through the field FSOS of the Transmit / Receive
Frame Mode Register (TFMR/RFMR).
Generating a Frame Sync signal is not possible without generating it on its related output.
462
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1768I–ATARM–09-Jul-09
AT91RM9200
Figure 31-10. Transmit Start Mode
TK
TF
(Input)
Start = Low Level on TF
Start = Falling Edge on TF
Start = High Level on TF
Start = Rising Edge on TF
Start = Level Change on TF
Start = Any Edge on TF
TD
(Output)
TD
(Output)
X
BO
BO
X
TD
(Output)
STTDLY
BO
X
X
BO
B1
STTDLY
BO
B1
BO
B1
BO
B1
BO
B1
BO
B1
X
TD
(Output)
STTDLY
B1
X
TD
(Output)
TD
(Output)
B1
STTDLY
B1
STTDLY
STTDLY
Figure 31-11. Receive Pulse/Edge Start Modes
RK
RF
(Input)
Start = Low Level on RF
Start = Falling Edge on RF
RD
(Input)
RD
(Input)
X
STTDLY
BO
X
Start = High Level on RF
Start = Level Change on RF
Start = Any Edge on RF
31.6.5
BO
B1
STTDLY
BO
B1
BO
B1
BO
B1
BO
B1
X
RD
(Input)
RD
(Input)
RD
(Input)
STTDLY
X
RD
(Input)
Start = Rising Edge on RF
B1
X
X
BO
STTDLY
B1
STTDLY
STTDLY
Frame Sync
The Transmitter and Receiver Frame Sync pins, TF and RF, can be programmed to generate
different kinds of frame synchronization signals. The Frame Sync Output Selection (FSOS) field
in the Receive Frame Mode Register (SSC_RFMR) and in the Transmit Frame Mode Register
(SSC_TFMR) 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.
463
1768I–ATARM–09-Jul-09
If a pulse waveform is selected, the Frame Sync Length (FSLEN) field in SSC_RFMR and
SSC_TFMR programs the length of the pulse, from 1-bit time up to 16-bit time.
The periodicity of the Receive and Transmit Frame Sync pulse output can be programmed
through the Period Divider Selection (PERIOD) field in SSC_RCMR and SSC_TCMR.
31.6.5.1
Frame Sync Data
Frame Sync Data transmits or receives a specific tag during the Frame Synchro signal.
During the Frame Sync signal, the Receiver can sample the RD line and store the data in the
Receive Sync Holding Register and the transmitter can transfer Transmit Sync Holding Register
in the Shifter Register. The data length to be sampled/shifted out during the Frame Sync signal
is programmed by the FSLEN field in SSC_RFMR/SSC_TFMR.
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 Receive Sync Holding Register through the Receive Shift Register.
The Transmit Frame Sync Operation is performed by the transmitter only if the bit Frame Sync
Data Enable (FSDEN) in SSC_TFMR is set. 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 Transmit Sync Holding Register is transferred in the Transmit Register then shifted out.
31.6.5.2
31.6.6
Frame Sync Edge Detection
The Frame Sync Edge detection is programmed by the FSEDGE field in
SSC_RFMR/SSC_TFMR. This sets the corresponding flags RXSYN/TXSYN in the SSC Status
Register (SSC_SR) on frame synchro edge detection (signals RF/TF).
Data Format
The data framing format of both the transmitter and the receiver are largely programmable
through the Transmitter Frame Mode Register (SSC_TFMR) and the Receiver Frame Mode
Register (SSC_RFMR). In either case, the user can independently select:
• The event that starts the data transfer (START).
• The delay in number of bit periods between the start event and the first data bit (STTDLY).
• The length of the data (DATLEN)
• The number of data to be transferred for each start event (DATNB).
• The length of Synchronization transferred for each start event (FSLEN).
• The bit sense: most or lowest significant bit first (MSBF).
Additionally, the transmitter can be used to transfer Synchronization and select the level
driven on the TD pin while not in data transfer operation. This is done respectively by the
Frame Sync Data Enable (FSDEN) and by the Data Default Value (DATDEF) bits in
SSC_TFMR.
464
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AT91RM9200
Table 31-3.
Data Frame Registers
Transmitter
Receiver
Field
Length
Comment
SSC_TFMR
SSC_RFMR
DATLEN
Up to 32
Size of word
SSC_TFMR
SSC_RFMR
DATNB
Up to 16
Number Word transmitter in frame
SSC_TFMR
SSC_RFMR
MSBF
SSC_TFMR
SSC_RFMR
FSLEN
Up to 16
Size of Synchro data register
SSC_TFMR
DATDEF
0 or 1
Data default value ended
SSC_TFMR
FSDEN
1 most significant bit in first
Enable send SSC_TSHR
SSC_TCMR
SSC_RCMR
PERIOD
up to 512
Frame size
SSC_TCMR
SSC_RCMR
STTDLY
up to 255
Size of transmit start delay
Figure 31-12. Transmit and Receive Frame Format in Edge/Pulse Start Modes
Start
Start
PERIOD
TF/RF(1)
FSLEN
TD
(If FSDEN = 1)
Data
Data
From SSC_TSHR FromDATDEF
From SSC_THR
From SSC_THR
Default
Data
Data
Sync Data
TD
(If FSDEN = 0)
RD
Default
From SSC_THR
From DATDEF
Sync Data
Ignored
STTDLY
Data
To SSC_RHR
To SSC_RHR
DATLEN
DATLEN
Sync Data
FromDATDEF
From SSC_THR
Data
To SSC_RSHR
Default
Default
From DATDEF
Ignored
Sync Data
DATNB
Note:
1. Input on falling edge on TF/RF example.
Figure 31-13. Transmit Frame Format in Continuous Mode
Start
TD
Data
From SSC_THR
DATLEN
Data
Default
From SSC_THR
DATLEN
Start: 1. TXEMPTY set to 1
2. Write to the SSC_THR
Note:
1. STTDLY is set to 0. In this example, SSC_THR is loaded twice. The value of FSDEN has no
effect on transmission. SyncData cannot be output in continuous mode.
465
1768I–ATARM–09-Jul-09
Figure 31-14. Receive Frame Format in Continuous Mode
Start = Enable Receiver
RD
Note:
31.6.7
Data
Data
To SSC_RHR
To SSC_RHR
DATLEN
DATLEN
1. STTDLY is set to 0.
Loop Mode
The receiver can be programmed to receive transmissions from the transmitter. This is done by
setting the Loop Mode (LOOP) bit in SSC_RFMR. In this case, RD is connected to TD, RF is
connected to TF and RK is connected to TK.
31.6.8
Interrupt
Most bits in SSC_SR have a corresponding bit in interrupt management registers.
The SSC Controller can be programmed to generate an interrupt when it detects an event. The
Interrupt is controlled by writing SSC_IER (Interrupt Enable Register) and SSC_IDR (Interrupt
Disable Register), which respectively enable and disable the corresponding interrupt by setting
and clearing the corresponding bit in SSC_IMR (Interrupt Mask Register), which controls the
generation of interrupts by asserting the SSC interrupt line connected to the AIC.
Figure 31-15. Interrupt Block Diagram
SSC_IMR
SSC_IER
PDC
SSC_IDR
Set
Clear
TXBUFE
ENDTX
Transmitter
TXRDY
TXEMPTY
TXSYNC
Interrupt
Control
RXBUFF
ENDRX
SSC Interrupt
Receiver
RXRDY
OVRUN
RXSYNC
31.7
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.
466
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1768I–ATARM–09-Jul-09
AT91RM9200
Figure 31-16. Audio Application Block Diagram
Clock SCK
TK
Word Select WS
I2S
RECEIVER
TF
Data SD
SSC
TD
RD
Clock SCK
RF
Word Select WS
RK
Data SD
MSB
LSB
MSB
Right Channel
Left Channel
Figure 31-17. Codec Application Block Diagram
Serial Data Clock (SCLK)
TK
Frame sync (FSYNC)
TF
Serial Data Out
SSC
CODEC
TD
Serial Data In
RD
RF
Serial Data Clock (SCLK)
RK
First Time Slot
Frame sync (FSYNC)
Dstart
Dend
Serial Data Out
Serial Data In
467
1768I–ATARM–09-Jul-09
Figure 31-18. Time Slot Application Block Diagram
SCLK
TK
FSYNC
TF
CODEC
First
Time Slot
Data Out
TD
SSC
Data in
RD
RF
RK
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
468
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31.8
Serial Synchronous Controller (SSC) User Interface
Table 31-4.
SSC Register Mapping
Offset
Register
Register Name
Access
Reset
SSC_CR
Write
–
SSC_CMR
Read/Write
0x0
0x0
Control Register
0x4
Clock Mode Register
0x8
Reserved
–
–
–
0xC
Reserved
–
–
–
0x10
Receive Clock Mode Register
SSC_RCMR
Read/Write
0x0
0x14
Receive Frame Mode Register
SSC_RFMR
Read/Write
0x0
0x18
Transmit Clock Mode Register
SSC_TCMR
Read/Write
0x0
0x1C
Transmit Frame Mode Register
SSC_TFMR
Read/Write
0x0
0x20
Receive Holding Register
SSC_RHR
Read
0x0
0x24
Transmit Holding Register
SSC_THR
Write
–
0x28
Reserved
–
–
–
0x2C
Reserved
–
–
–
0x30
Receive Sync. Holding Register
SSC_RSHR
Read
0x0
0x34
Transmit Sync. Holding Register
SSC_TSHR
Read/Write
0x0
0x38
Reserved
–
–
–
0x3C
Reserved
–
–
–
0x40
Status Register
SSC_SR
Read
0x000000CC
0x44
Interrupt Enable Register
SSC_IER
Write
–
0x48
Interrupt Disable Register
SSC_IDR
Write
–
0x4C
Interrupt Mask Register
SSC_IMR
Read
0x0
Reserved
–
–
–
Reserved for Peripheral DMA Controller (PDC)
–
–
–
0x50-0xFF
0x100- 0x124
469
1768I–ATARM–09-Jul-09
31.8.1
SSC Control Register
Register Name:
SSC_CR
Access Type:
31
–
23
–
15
SWRST
7
–
Write-only
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
–
28
–
20
–
12
–
4
–
27
–
19
–
11
–
3
–
26
–
18
–
10
–
2
–
25
–
17
–
9
TXDIS
1
RXDIS
24
–
16
–
8
TXEN
0
RXEN
• RXEN: Receive Enable
0: No effect.
1: Enables Data Receive if RXDIS is not set(1).
• RXDIS: Receive Disable
0: No effect.
1: Disables Data Receive(1).
• TXEN: Transmit Enable
0: No effect.
1: Enables Data Transmit if TXDIS is not set(1).
• TXDIS: Transmit Disable
0: No effect.
1: Disables Data Transmit(1).
• SWRST: Software Reset
0: No effect.
1: Performs a software reset. Has priority on any other bit in SSC_CR.
Note: 1.
470
Only the data management is affected
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1768I–ATARM–09-Jul-09
AT91RM9200
31.8.2
SSC Clock Mode Register
Register Name:
SSC_CMR
Access Type:
31
–
23
–
15
–
7
Read/Write
30
–
22
–
14
–
6
29
–
21
–
13
–
5
28
–
20
–
12
–
4
27
–
19
–
11
26
–
18
–
10
3
2
25
–
17
–
9
24
–
16
–
8
1
0
DIV
DIV
• DIV: Clock Divider
0: The Clock Divider is not active.
Any Other Value: The Divided Clock equals the Master Clock divided by 2 times DIV. The maximum bit rate is MCK/2. The
minimum bit rate is MCK/2 x 4095 = MCK/8190.
31.8.3
SSC Receive Clock Mode Register
Register Name:
SSC_RCMR
Access Type:
31
Read/Write
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
PERIOD
23
22
21
20
15
–
7
–
14
–
6
–
13
–
5
CKI
12
–
4
STTDLY
START
3
CKO
2
1
0
CKS
• CKS: Receive Clock Selection
CKS
Selected Receive Clock
0x0
Divided Clock
0x1
TK Clock Signal
0x2
RK Pin
0x3
Reserved
• CKO: Receive Clock Output Mode Selection
CKO
Receive Clock Output Mode
0x0
None
0x1
Continuous Receive Clock
0x2-0x7
RK pin
Input-only
Output
Reserved
471
1768I–ATARM–09-Jul-09
• CKI: Receive Clock Inversion
0: The data and the Frame Sync signal are sampled on Receive Clock falling edge.
1: The data and the Frame Sync signal are shifted out on Receive Clock rising edge.
CKI does not affects the RK output clock signal.
• START: Receive Start Selection
START
Receive Start
0x0
Continuous, as soon as the receiver is enabled, and immediately after the end of transfer of the previous data.
0x1
Transmit Start
0x2
Detection of a low level on RF input
0x3
Detection of a high level on RF input
0x4
Detection of a falling edge on RF input
0x5
Detection of a rising edge on RF input
0x6
Detection of any level change on RF input
0x7
Detection of any edge on RF input
0x8-0xF
Reserved
• STTDLY: Receive Start Delay
If STTDLY is not 0, 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.
Please Note: It is very important that STTDLY be set carefully. If STTDLY must be set, it should be done in relation to TAG
(Receive Sync Data) reception.
• PERIOD: Receive Period Divider Selection
This field selects the divider to apply to the selected Receive Clock in order to generate a new Frame Sync Signal. If 0, no
PERIOD signal is generated. If not 0, a PERIOD signal is generated each 2 x (PERIOD+1) Receive Clock.
472
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
31.8.4
SSC Receive Frame Mode Register
Register Name:
SSC_RFMR
Access Type:
31
–
23
–
15
–
7
MSBF
Read/Write
30
–
22
14
–
6
–
29
–
21
FSOS
13
–
5
LOOP
28
–
20
27
–
19
26
–
18
12
–
4
11
10
25
–
17
24
FSEDGE
16
9
8
1
0
FSLEN
DATNB
3
2
DATLEN
• DATLEN: Data Length
0x0 is not supported. The value of DATLEN can be set between 0x1 and 0x1F.
The bit stream contains DATLEN + 1 data bits. Moreover, it defines the transfer size performed by the PDC assigned to the
Receiver.
If DATLEN is less than or equal to 7, data transfers are in bytes. If DATLEN is between 8 and 15 (included), half-words are
transferred. For any other value, 32-bit words are transferred.
• LOOP: Loop Mode
0: Normal operating mode.
1: RD is driven by TD, RF is driven by TF and TK drives RK.
• MSBF: Most Significant Bit First
0: The lowest significant bit of the data register is sampled first in the bit stream.
1: The most significant bit of the data register is sampled first in the bit stream.
• DATNB: Data Number per Frame
This field defines the number of data words to be received after each transfer start. If 0, only 1 data word is transferred. Up
to 16 data words can be transferred.
• 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 Receive
Sync Data Register. Only when FSOS is set on negative or positive pulse.
• FSOS: Receive Frame Sync Output Selection
FSOS
Selected Receive Frame Sync Signal
RF pin
0x0
None
0x1
Negative Pulse
Output
0x2
Positive Pulse
Output
0x3
Driven Low during data transfer
Output
0x4
Driven High during data transfer
Output
0x5
Toggling at each start of data transfer
Output
0x6-0x7
Reserved
Input-only
Undefined
473
1768I–ATARM–09-Jul-09
• FSEDGE: Frame Sync Edge Detection
Determines which edge on Frame Sync sets RXSYN in the SSC Status Register.
FSEDGE
474
Frame Sync Edge Detection
0x0
Positive Edge Detection
0x1
Negative Edge Detection
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
31.8.5
SSC Transmit Clock Mode Register
Register Name:
SSC_TCMR
Access Type:
31
Read/Write
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
1
0
PERIOD
23
22
21
20
15
–
7
–
14
–
6
–
13
–
5
CKI
12
–
4
STTDLY
START
3
CKO
2
CKS
• CKS: Transmit Clock Selection
CKS
Selected Transmit Clock
0x0
Divided Clock
0x1
RK Clock signal
0x2
TK Pin
0x3
Reserved
• CKO: Transmit Clock Output Mode Selection
CKO
Transmit Clock Output Mode
0x0
None
0x1
Continuous Transmit Clock
0x2-0x7
TK pin
Input-only
Output
Reserved
• CKI: Transmit Clock Inversion
0: The data and the Frame Sync signal are shifted out on Transmit Clock falling edge.
1: The data and the Frame Sync signal are shifted out on Transmit Clock rising edge.
CKI affects only the Transmit Clock and not the output clock signal.
• START: Transmit Start Selection
START
Transmit Start
0x0
Continuous, as soon as a word is written in the SSC_THR Register (if Transmit is enabled) and
immediately after the end of transfer of the previous data.
0x1
Receive Start
0x2
Detection of a low level on TF signal
0x3
Detection of a high level on TF signal
0x4
Detection of a falling edge on TF signal
0x5
Detection of a rising edge on TF signal
0x6
Detection of any level change on TF signal
0x7
Detection of any edge on TF signal
0x8-0xF
Reserved
475
1768I–ATARM–09-Jul-09
• STTDLY: Transmit Start Delay
If STTDLY is not 0, a delay of STTDLY clock cycles is inserted between the start event and the actual start of transmission
of data. When the Transmitter is programmed to start synchronously with the Receiver, the delay is also applied.
Please Note: STTDLY must be set carefully. If STTDLY is too short in respect to TAG (Transmit Sync Data) emission, data
is emitted instead of the end of TAG.
• PERIOD: Transmit Period Divider Selection
This field selects the divider to apply to the selected Transmit Clock to generate a new Frame Sync Signal. If 0, no period
signal is generated. If not 0, a period signal is generated at each 2 x (PERIOD+1) Transmit Clock.
476
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
31.8.6
SSC Transmit Frame Mode Register
Register Name:
SSC_TFMR
Access Type:
31
–
23
FSDEN
15
–
7
MSBF
Read/Write
30
–
22
14
–
6
–
29
–
21
FSOS
13
–
5
DATDEF
28
–
20
27
–
19
26
–
18
12
–
4
11
10
25
–
17
24
FSEDGE
16
9
8
1
0
FSLEN
DATNB
3
2
DATLEN
• DATLEN: Data Length
0x0 is not supported. The value of DATLEN can be set between 0x1 and 0x1F.
The bit stream contains DATLEN + 1 data bits. Moreover, it defines the transfer size performed by the PDC assigned to the
Receiver.
If DATLEN is less than or equal to 7, data transfers are in bytes. If DATLEN is between 8 and 15 (included), half-words are
transferred. For any other value, 32-bit words are transferred.
• DATDEF: Data Default Value
This bit defines the level driven on the TD pin while out of transmission. Note that if the pin is defined as multi-drive by the
PIO Controller, the pin is enabled only if the SCC TD output is 1.
• MSBF: Most Significant Bit First
0: The lowest significant bit of the data register is shifted out first in the bit stream.
1: The most significant bit of the data register is shifted out first in the bit stream.
• DATNB: Data Number per frame
This field defines the number of data words to be transferred after each transfer start. If 0, only 1 data word is transferred
and up to 16 data words can be transferred.
• 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 Transmit Sync
Data Register if FSDEN is 1. If 0, the Transmit Frame Sync signal is generated during one Transmit Clock period and up to
16 clock period pulse length is possible.
• FSOS: Transmit Frame Sync Output Selection
FSOS
Selected Transmit Frame Sync Signal
TF pin
0x0
None
0x1
Negative Pulse
Output
0x2
Positive Pulse
Output
0x3
Driven Low during data transfer
Output
0x4
Driven High during data transfer
Output
0x5
Toggling at each start of data transfer
Output
0x6-0x7
Reserved
Input-only
Undefined
477
1768I–ATARM–09-Jul-09
• FSDEN: Frame Sync Data Enable
0: The TD line is driven with the default value during the Transmit Frame Sync signal.
1: SSC_TSHR value is shifted out during the transmission of the Transmit Frame Sync signal.
• FSEDGE: Frame Sync Edge Detection
Determines which edge on frame sync sets TXSYN (Status Register).
FSEDGE
Frame Sync Edge Detection
0x0
Positive Edge Detection
0x1
Negative Edge Detection
31.8.7
SSC Receive Holding Register
Register Name:
SSC_RHR
Access Type:
31
Read-only
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
RDAT
23
22
21
20
RDAT
15
14
13
12
7
6
5
4
RDAT
RDAT
• RDAT: Receive Data
Right aligned regardless of the number of data bits defined by DATLEN in SSC_RFMR.
31.8.8
SSC Transmit Holding Register
Register Name:
SSC_THR
Access Type:
31
Write only
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
TDAT
23
22
21
20
TDAT
15
14
13
12
TDAT
7
6
5
4
TDAT
TDAT: Transmit Data
Right aligned regardless of the number of data bits defined by DATLEN in SSC_TFMR.
478
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
31.8.9
SSC Receive Synchronization Holding Register
Register Name:
SSC_RSHR
Access Type:
Read/Write
31
–
23
–
15
30
–
22
–
14
29
–
21
–
13
28
–
20
–
12
7
6
5
4
27
–
19
–
11
26
–
18
–
10
25
–
17
–
9
24
–
16
–
8
3
2
1
0
RSDAT
RSDAT
• RSDAT: Receive Synchronization Data
Right aligned regardless of the number of data bits defined by FSLEN in SSC_RFMR.
31.8.10
Name:
SSC Transmit Synchronization Holding Register
SSC_TSHR
Access Type:
Read/Write
31
–
23
–
15
30
–
22
–
14
29
–
21
–
13
28
–
20
–
12
7
6
5
4
27
–
19
–
11
26
–
18
–
10
25
–
17
–
9
24
–
16
–
8
3
2
1
0
TSDAT
TSDAT
• TSDAT: Transmit Synchronization Data
Right aligned regardless of the number of data bits defined by FSLEN in SSC_TFMR.
479
1768I–ATARM–09-Jul-09
31.8.11 SSC Status Register
Register Name:
SSC_SR
Access Type:
31
–
23
–
15
–
7
RXBUFF
Read-only
30
–
22
–
14
–
6
ENDRX
29
–
21
–
13
–
5
OVRUN
28
–
20
–
12
–
4
RXRDY
27
–
19
–
11
RXSYN
3
TXBUFE
26
–
18
–
10
TXSYN
2
ENDTX
25
–
17
RXEN
9
–
1
TXEMPTY
24
–
16
TXEN
8
–
0
TXRDY
• TXRDY: Transmit Ready
0: Data has been loaded in SSC_THR and is waiting to be loaded in the Transmit Shift Register.
1: SSC_THR is empty.
• TXEMPTY: Transmit Empty
0: Data remains in SSC_THR or is currently transmitted from Transmit Shift Register.
1: Last data written in SSC_THR has been loaded in Transmit Shift Register and transmitted by it.
• ENDTX: End of Transmission
0: The register SSC_TCR has not reached 0 since the last write in SSC_TCR or SSC_TNCR.
1: The register SSC_TCR has reached 0 since the last write in SSC_TCR or SSC_TNCR.
• TXBUFE: Transmit Buffer Empty
0: SSC_TCR or SSC_TNCR have a value other than 0.
1: Both SSC_TCR and SSC_TNCR have a value of 0.
• RXRDY: Receive Ready
0: SSC_RHR is empty.
1: Data has been received and loaded in SSC_RHR.
• OVRUN: Receive Overrun
0: No data has been loaded in SSC_RHR while previous data has not been read since the last read of the Status Register.
1: Data has been loaded in SSC_RHR while previous data has not yet been read since the last read of the Status Register.
• ENDRX: End of Reception
0: Data is written on the Receive Counter Register or Receive Next Counter Register.
1: End of PDC transfer when Receive Counter Register has arrived at zero.
• RXBUFF: Receive Buffer Full
0: SSC_RCR or SSC_RNCR have a value other than 0.
1: Both SSC_RCR and SSC_RNCR have a value of 0.
• TXSYN: Transmit Sync
480
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
0: A Tx Sync has not occurred since the last read of the Status Register.
1: A Tx Sync has occurred since the last read of the Status Register.
• RXSYN: Receive Sync
0: A Rx Sync has not occurred since the last read of the Status Register.
1: A Rx Sync has occurred since the last read of the Status Register.
• TXEN: Transmit Enable
0: Transmit data is disabled.
1: Transmit data is enabled.
• RXEN: Receive Enable
0: Receive data is disabled.
1: Receive data is enabled.
481
1768I–ATARM–09-Jul-09
31.8.12 SSC Interrupt Enable Register
Register Name:
SSC_IER
Access Type:
31
–
23
–
15
–
7
RXBUFF
Write-only
30
–
22
–
14
–
6
ENDRX
29
–
21
–
13
–
5
OVRUN
28
–
20
–
12
–
4
RXRDY
27
–
19
–
11
RXSYN
3
TXBUFE
26
–
18
–
10
TXSYN
2
ENDTX
25
–
17
–
9
–
1
TXEMPTY
24
–
16
–
8
–
0
TXRDY
• TXRDY: Transmit Ready
• TXEMPTY: Transmit Empty
• ENDTX: End of Transmission
• TXBUFE: Transmit Buffer Empty
• RXRDY: Receive Ready
• OVRUN: Receive Overrun
• ENDRX: End of Reception
• RXBUFF: Receive Buffer Full
• TXSYN: Tx Sync
• RXSYN: Rx Sync
0: No effect.
1: Enables the corresponding interrupt.
482
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
31.8.13 SSC Interrupt Disable Register
Register Name:
SSC_IDR
Access Type:
31
–
23
–
15
–
7
RXBUFF
Write-only
30
–
22
–
14
–
6
ENDRX
29
–
21
–
13
–
5
OVRUN
28
–
20
–
12
–
4
RXRDY
27
–
19
–
11
RXSYN
3
TXBUFE
26
–
18
–
10
TXSYN
2
ENDTX
25
–
17
–
9
–
1
TXEMPTY
24
–
16
–
8
–
0
TXRDY
• TXRDY: Transmit Ready
• TXEMPTY: Transmit Empty
• ENDTX: End of Transmission
• TXBUFE: Transmit Buffer Empty
• RXRDY: Receive Ready
• OVRUN: Receive Overrun
• ENDRX: End of Reception
• RXBUFF: Receive Buffer Full
• TXSYN: Tx Sync
• RXSYN: Rx Sync
0: No effect.
1: Disables the corresponding interrupt.
483
1768I–ATARM–09-Jul-09
31.8.14 SSC Interrupt Mask Register
Register Name:
SSC_IMR
Access Type:
31
–
23
–
15
–
7
RXBUFF
Read-only
30
–
22
–
14
–
6
ENDRX
29
–
21
–
13
–
5
OVRUN
28
–
20
–
12
–
4
RXRDY
27
–
19
–
11
RXSYN
3
TXBUFE
26
–
18
–
10
TXSYN
2
ENDTX
25
–
17
–
9
–
1
TXEMPTY
24
–
16
–
8
–
0
TXRDY
• TXRDY: Transmit Ready
• TXEMPTY: Transmit Empty
• ENDTX: End of Transmission
• TXBUFE: Transmit Buffer Empty
• RXRDY: Receive Ready
• OVRUN: Receive Overrun
• ENDRX: End of Reception
• RXBUFF: Receive Buffer Full
• TXSYN: Tx Sync
• RXSYN: Rx Sync
0: The corresponding interrupt is disabled.
1: The corresponding interrupt is enabled.
484
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
32. Timer Counter (TC)
32.1
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 Timer Counter block has two global registers which act upon all three TC channels.
The Block Control Register allows the three channels to be started simultaneously with the same
instruction.
The Block Mode Register defines the external clock inputs for each channel, allowing them to be
chained.
Key Features of the Timer Counter are:
• 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
485
1768I–ATARM–09-Jul-09
32.2
Block Diagram
Figure 32-1. Timer Counter Block Diagram
Parallel I/O
Controller
TIMER_CLOCK1
TCLK0
TIMER_CLOCK2
TIOA1
XC0
TIOA2
TIMER_CLOCK3
TCLK1
XC1
TCLK2
XC2
Timer/Counter
Channel 0
TIOA
TIOA0
TIOB0
TIOA0
TIOB
TIMER_CLOCK4
TIMER_CLOCK5
TC0XC0S
TIOB0
SYNC
TCLK0
TCLK1
TCLK2
INT0
TCLK0
XC0
TCLK1
TIOA0
XC1
TIOA2
XC2
Timer/Counter
Channel 1
TIOA
TIOA1
TIOB1
TIOA1
TIOB
TCLK2
TC1XC1S
TCLK0
XC0
TCLK1
XC1
TCLK2
XC2
TIOB1
SYNC
Timer/Counter
Channel 2
INT1
TIOA
TIOA2
TIOB2
TIOA2
TIOB
TIOA0
TC2XC2S
TIOA1
TIOB2
SYNC
INT2
Timer Counter
Advanced
Interrupt
Controller
Table 32-1.
Signal Name Description
Block/Channel
Signal Name
XC0, XC1, XC2
Channel Signal
Capture Mode: General-purpose Input
Waveform Mode: General-purpose Output
TIOB
Capture Mode: General-purpose Input
Waveform Mode: General-purpose Input/output
SYNC
TCLK0, TCLK1, TCLK2
486
External Clock Inputs
TIOA
INT
Block Signal
Description
Interrupt Signal Output
Synchronization Input Signal
External Clock Inputs
TIOA0
TIOA Signal for Channel 0
TIOB0
TIOB Signal for Channel 0
TIOA1
TIOA Signal for Channel 1
TIOB1
TIOB Signal for Channel 1
TIOA2
TIOA Signal for Channel 2
TIOB2
TIOB Signal for Channel 2
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
32.3
Pin Name List
Table 32-2.
32.4
Timer Counter pin list
Pin Name
Description
Type
TCLK0-TCLK2
External Clock Input
Input
TIOA0-TIOA2
I/O Line A
I/O
TIOB0-TIOB2
I/O Line B
I/O
Product Dependencies
For further details on the Timer Counter hardware implementation, see the specific Product
Properties document.
32.4.1
I/O Lines
The pins used for interfacing the compliant external devices may be multiplexed with PIO lines.
The programmer must first program the PIO controllers to assign the TC pins to their peripheral
functions.
32.4.2
Power Management
The TC must be clocked through the Power Management Controller (PMC), thus the programmer must first configure the PMC to enable the Timer Counter.
32.4.3
Interrupt
The TC interface has an interrupt line connected to the Advanced Interrupt Controller (AIC).
Handling the TC interrupt requires programming the AIC before configuring the TC.
32.5
Functional Description
32.5.1
32.5.1.1
TC Description
The three channels of the Timer Counter are independent and identical in operation. The registers for channel programming are listed in Table 32-2 on page 487.
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 COVFS bit in TC_SR (Status Register) is set.
The current value of the counter is accessible in real time by reading the Counter Value Register, TC_CV. 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.
32.5.1.2
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 TIOA0, TIOA1 or
TIOA2 for chaining by programming the TC_BMR (Block Mode). See Figure 32-2.
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
487
1768I–ATARM–09-Jul-09
• External clock signals: XC0, XC1 or XC2
This selection is made by the TCCLKS bits in the TC Channel Mode Register (Capture Mode).
The selected clock can be inverted with the CLKI bit in TC_CMR (Capture Mode). 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
parameter in the Mode Register defines this signal (none, XC0, XC1, XC2).
Note:
In all cases, if an external clock is used, the duration of each of its levels must be longer than the
master clock period. The external clock frequency must be at least 2.5 times lower than the master clock
Figure 32-2. Clock Selection
TCCLKS
TIMER_CLOCK1
TIMER_CLOCK2
CLKI
TIMER_CLOCK3
TIMER_CLOCK4
TIMER_CLOCK5
Selected
Clock
XC0
XC1
XC2
BURST
1
32.5.1.3
Clock Control
The clock of each counter can be controlled in two different ways: it can be enabled/disabled
and started/stopped. See Figure 32-3.
• The clock can be enabled or disabled by the user with the CLKEN and the CLKDIS
commands in the Control Register. In Capture Mode it can be disabled by an RB load event if
LDBDIS is set to 1 in TC_CMR. In Waveform Mode, it can be disabled by an RC Compare
event if CPCDIS is set to 1 in TC_CMR. When disabled, the start or the stop actions have no
effect: only a CLKEN command in the Control Register can re-enable the clock. When the
clock is enabled, the CLKSTA bit is set in the Status Register.
• The clock can also be started or stopped: a trigger (software, synchro, external or compare)
always starts the clock. The clock can be stopped by an RB load event in Capture Mode
(LDBSTOP = 1 in TC_CMR) or a RC compare event in Waveform Mode (CPCSTOP = 1 in
TC_CMR). The start and the stop commands have effect only if the clock is enabled.
488
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Figure 32-3. Clock Control
Selected
Clock
Trigger
CLKSTA
CLKEN
Q
Q
S
CLKDIS
S
R
R
Counter
Clock
32.5.1.4
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 is programmed with the WAVE bit in the TC Channel Mode Register.
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.
32.5.1.5
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 setting SWTRG in
TC_CCR.
• 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 TC_BCR (Block Control) with SYNC set.
• Compare RC Trigger: RC is implemented in each channel and can provide a trigger when the
counter value matches the RC value if CPCTRG is set in TC_CMR.
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 on one of the following signals: TIOB, XC0, XC1 or XC2. This external
event can then be programmed to perform a trigger by setting ENETRG in TC_CMR.
If an external trigger is used, the duration of the pulses must be longer than the master clock
period in order to be detected.
489
1768I–ATARM–09-Jul-09
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.
32.5.2
Capture Operating Mode
This mode is entered by clearing the WAVE parameter in TC_CMR (Channel Mode Register).
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 32-4 shows the configuration of the TC channel when programmed in Capture Mode.
32.5.2.1
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 LDRA parameter in TC_CMR defines the TIOA edge for the loading of register A, and the
LDRB parameter defines the TIOA edge for the loading of Register B.
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 Overrun Error Flag (LOVRS)
in TC_SR (Status Register). In this case, the old value is overwritten.
32.5.2.2
Trigger Conditions
In addition to the SYNC signal, the software trigger and the RC compare trigger, an external trigger can be defined.
The ABETRG bit in TC_CMR selects TIOA or TIOB input signal as an external trigger. The
ETRGEDG parameter defines the edge (rising, falling or both) detected to generate an external
trigger. If ETRGEDG = 0 (none), the external trigger is disabled.
490
AT91RM9200
1768I–ATARM–09-Jul-09
1768I–ATARM–09-Jul-09
MTIOA
MTIOB
1
If RA is not loaded
or RB is Loaded
Edge
Detector
ETRGEDG
SWTRG
Timer/Counter Channel
ABETRG
BURST
CLKI
S
R
OVF
LDRB
Edge
Detector
Edge
Detector
Capture
Register A
LDBSTOP
R
S
CLKEN
LDRA
If RA is Loaded
CPCTRG
16-bit Counter
RESET
Trig
CLK
Q
Q
CLKSTA
LDBDIS
Capture
Register B
CLKDIS
TC1_SR
TIOA
TIOB
SYNC
XC2
XC1
XC0
TIMER_CLOCK5
TIMER_CLOCK4
TIMER_CLOCK3
TIMER_CLOCK2
TIMER_CLOCK1
TCCLKS
Compare RC =
Register C
COVFS
INT
AT91RM9200
Figure 32-4. Capture Mode
CPCS
LOVRS
LDRBS
ETRGS
LDRAS
TC1_IMR
491
32.6
Waveform Operating Mode
Waveform operating mode is entered by setting the WAVE parameter in TC_CMR (Channel
Mode Register).
In Waveform Operating Mode the TC channel generates 1 or 2 PWM signals with the same frequency and independently programmable duty cycles, or generates different types of one-shot
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 (EEVT parameter in TC_CMR).
Figure 32-5 shows the configuration of the TC channel when programmed in Waveform Operating Mode.
32.6.0.3
Waveform Selection
Depending on the WAVSEL parameter in TC_CMR (Channel Mode Register), the behavior of
TC_CV 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.
492
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1768I–ATARM–09-Jul-09
1768I–ATARM–09-Jul-09
TIOB
SYNC
XC2
XC1
XC0
TIMER_CLOCK5
TIMER_CLOCK4
TIMER_CLOCK3
TIMER_CLOCK2
TIMER_CLOCK1
1
EEVT
BURST
Timer/Counter Channel
Edge
Detector
EEVTEDG
SWTRG
ENETRG
CLKI
Trig
CLK
R
S
OVF
WAVSEL
RESET
16-bit Counter
WAVSEL
Q
Compare RA =
Register A
Q
CLKSTA
Compare RC =
Compare RB =
CPCSTOP
CPCDIS
Register C
CLKDIS
Register B
R
S
CLKEN
CPAS
INT
BSWTRG
BEEVT
BCPB
BCPC
ASWTRG
AEEVT
ACPA
ACPC
Output Controller
Output Controller
TCCLKS
TIOB
MTIOB
TIOA
MTIOA
AT91RM9200
Figure 32-5. Waveform Mode
CPCS
CPBS
COVFS
TC1_SR
ETRGS
TC1_IMR
493
WAVSEL = 00
When WAVSEL = 00, the value of TC_CV is incremented from 0 to 0xFFFF. Once 0xFFFF has
been reached, the value of TC_CV is reset. Incrementation of TC_CV starts again and the cycle
continues. See Figure 32-6.
An external event trigger or a software trigger can reset the value of TC_CV. It is important to
note that the trigger may occur at any time. See Figure 32-7.
RC Compare cannot be programmed to generate a trigger in this configuration. At the same
time, RC Compare can stop the counter clock (CPCSTOP = 1 in TC_CMR) and/or disable the
counter clock (CPCDIS = 1 in TC_CMR).
Figure 32-6. WAVSEL= 00 without trigger
Counter Value
Counter cleared by compare match with 0xFFFF
0xFFFF
RC
RB
RA
Waveform Examples
Time
TIOB
TIOA
494
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Figure 32-7. WAVSEL= 00 with trigger
Counter cleared by compare match with 0xFFFF
Counter Value
0xFFFF
Counter cleared by trigger
RC
RB
RA
Time
Waveform Examples
TIOB
TIOA
WAVSEL = 10
When WAVSEL = 10, the value of TC_CV is incremented from 0 to the value of RC, then automatically reset on a RC Compare. Once the value of TC_CV has been reset, it is then
incremented and so on. See Figure 32-8.
It is important to note that TC_CV can be reset at any time by an external event or a software
trigger if both are programmed correctly. See Figure 32-9.
In addition, RC Compare can stop the counter clock (CPCSTOP = 1 in TC_CMR) and/or disable
the counter clock (CPCDIS = 1 in TC_CMR).
Figure 32-8. WAVSEL = 10 Without Trigger
Counter Value
0xFFFF
Counter cleared by compare match with RC
RC
RB
RA
Waveform Examples
Time
TIOB
TIOA
495
1768I–ATARM–09-Jul-09
Figure 32-9. WAVSEL = 10 With Trigger
Counter Value
0xFFFF
Counter cleared by compare match with RC
Counter cleared by trigger
RC
RB
RA
Time
Waveform Examples
TIOB
TIOA
WAVSEL = 01
When WAVSEL = 01, the value of TC_CV is incremented from 0 to 0xFFFF. Once 0xFFFF is
reached, the value of TC_CV is decremented to 0, then re-incremented to 0xFFFF and so on.
See Figure 32-10.
A trigger such as an external event or a software trigger can modify TC_CV at any time. If a trigger occurs while TC_CV is incrementing, TC_CV then decrements. If a trigger is received while
TC_CV is decrementing, TC_CV then increments. See Figure 32-11.
RC Compare cannot be programmed to generate a trigger in this configuration.
At the same time, RC Compare can stop the counter clock (CPCSTOP = 1) and/or disable the
counter clock (CPCDIS = 1).
496
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1768I–ATARM–09-Jul-09
AT91RM9200
Figure 32-10. WAVSEL = 01 Without Trigger
Counter decremented by compare match with 0xFFFF
Counter Value
0xFFFF
RC
RB
RA
Time
Waveform Examples
TIOB
TIOA
Figure 32-11. WAVSEL = 01 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
WAVSEL = 11
When WAVSEL = 11, the value of TC_CV is incremented from 0 to RC. Once RC is reached, the
value of TC_CV is decremented to 0, then re-incremented to RC and so on. See Figure 32-12.
A trigger such as an external event or a software trigger can modify TC_CV at any time. If a trigger occurs while TC_CV is incrementing, TC_CV then decrements. If a trigger is received while
TC_CV is decrementing, TC_CV then increments. See Figure 32-13.
RC Compare can stop the counter clock (CPCSTOP = 1) and/or disable the counter clock
(CPCDIS = 1).
497
1768I–ATARM–09-Jul-09
Figure 32-12. WAVSEL = 11 Without Trigger
Counter Value
0xFFFF
Counter decremented by compare match with RC
RC
RB
RA
Time
Waveform Examples
TIOB
TIOA
Figure 32-13. WAVSEL = 11 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
Time
TIOB
TIOA
32.6.0.4
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 parameter EEVT parameter in TC_CMR selects the external trigger. The EEVTEDG parameter defines the trigger edge for each of the possible external triggers (rising, falling or both). If
EEVTEDG is cleared (none), no external event is defined.
If TIOB is defined as an external event signal (EEVT = 0), TIOB is no longer used as an output
and the TC channel can only generate a waveform on TIOA.
498
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
When an external event is defined, it can be used as a trigger by setting bit ENETRG in
TC_CMR.
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 parameter WAVSEL.
32.6.0.5
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 and 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 corresponding parameter in
TC_CMR.
499
1768I–ATARM–09-Jul-09
32.7
Timer Counter (TC) User Interface
Table 32-3.
Offset
Timer Counter Global Memory Map
Channel/Register
Name
Access
Reset Value
0x00
TC Channel 0
0x40
TC Channel 1
0x80
TC Channel 2
0xC0
TC Block Control Register
TC_BCR
Write-only
–
0xC4
TC Block Mode Register
TC_BMR
Read/Write
0
See Table 32-4
See Table 32-4
See Table 32-4
TC_BCR (Block Control Register) and TC_BMR (Block Mode Register) control the whole TC block. TC channels are controlled by the registers listed in Table 32-4. The offset of each of the channel registers in Table 32-4 is in relation to the offset
of the corresponding channel as mentioned in Table 32-4.
Table 32-4.
Offset
Register
Name
Access
Reset Value
0x00
Channel Control Register
TC_CCR
Write-only
–
0x04
Channel Mode Register
TC_CMR
Read/Write
0
0x08
Reserved
–
0x0C
Reserved
–
0x10
Counter Value
TC_CV
Read-only
0
(1)
0
0x14
Register A
TC_RA
Read/Write
0x18
Register B
TC_RB
Read/Write(1)
0
0x1C
Register C
TC_RC
Read/Write
0
0x20
Status Register
TC_SR
Read-only
0
0x24
Interrupt Enable Register
TC_IER
Write-only
–
0x28
Interrupt Disable Register
TC_IDR
Write-only
–
0x2C
Interrupt Mask Register
TC_IMR
Read-only
0
Notes:
500
Timer Counter Channel Memory Map
1. Read only if WAVE = 0
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
32.7.1
TC Block Control Register
Register Name:
TC_BCR
Access Type:
Write-only
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
–
–
–
–
–
–
–
SYNC
• SYNC: Synchro Command
0 = No effect.
1 = Asserts the SYNC signal which generates a software trigger simultaneously for each of the channels.
501
1768I–ATARM–09-Jul-09
32.7.2
TC Block Mode Register
Register Name:
TC_BMR
Access Type:
Read/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
–
–
TC2XC2S
TCXC1S
0
TC0XC0S
• TC0XC0S: External Clock Signal 0 Selection
TC0XC0S
Signal Connected to XC0
0
0
TCLK0
0
1
none
1
0
TIOA1
1
1
TIOA2
• TC1XC1S: External Clock Signal 1 Selection
TC1XC1S
Signal Connected to XC1
0
0
TCLK1
0
1
none
1
0
TIOA0
1
1
TIOA2
• TC2XC2S: External Clock Signal 2 Selection
TC2XC2S
502
Signal Connected to XC2
0
0
TCLK2
0
1
none
1
0
TIOA0
1
1
TIOA1
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
32.7.3
TC Channel Control Register
Register Name:
TC_CCR
Access Type:
Write-only
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
–
–
–
–
–
SWTRG
CLKDIS
CLKEN
• CLKEN: Counter Clock Enable Command
0 = No effect.
1 = Enables the clock if CLKDIS is not 1.
• CLKDIS: Counter Clock Disable Command
0 = No effect.
1 = Disables the clock.
• SWTRG: Software Trigger Command
0 = No effect.
1 = A software trigger is performed: the counter is reset and the clock is started.
503
1768I–ATARM–09-Jul-09
32.7.4
TC Channel Mode Register: Capture Mode
Register Name:
TC_CMR
Access Type:
Read/Write
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
–
–
–
–
15
14
13
12
11
10
WAVE = 0
CPCTRG
–
–
–
ABETRG
7
6
5
3
2
LDBDIS
LDBSTOP
4
BURST
16
LDRB
CLKI
LDRA
9
8
ETRGEDG
1
0
TCCLKS
• TCCLKS: Clock Selection
TCCLKS
Clock Selected
0
0
0
TIMER_CLOCK1
0
0
1
TIMER_CLOCK2
0
1
0
TIMER_CLOCK3
0
1
1
TIMER_CLOCK4
1
0
0
TIMER_CLOCK5
1
0
1
XC0
1
1
0
XC1
1
1
1
XC2
• CLKI: Clock Invert
0 = Counter is incremented on rising edge of the clock.
1 = Counter is incremented on falling edge of the clock.
• BURST: Burst Signal Selection
BURST
0
0
The clock is not gated by an external signal.
0
1
XC0 is ANDed with the selected clock.
1
0
XC1 is ANDed with the selected clock.
1
1
XC2 is ANDed with the selected clock.
• LDBSTOP: Counter Clock Stopped with RB Loading
0 = Counter clock is not stopped when RB loading occurs.
1 = Counter clock is stopped when RB loading occurs.
• LDBDIS: Counter Clock Disable with RB Loading
0 = Counter clock is not disabled when RB loading occurs.
1 = Counter clock is disabled when RB loading occurs.
504
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
• ETRGEDG: External Trigger Edge Selection
ETRGEDG
Edge
0
0
none
0
1
rising edge
1
0
falling edge
1
1
each edge
• ABETRG: TIOA or TIOB External Trigger Selection
0 = TIOB is used as an external trigger.
1 = TIOA is used as an external trigger.
• CPCTRG: RC Compare Trigger Enable
0 = RC Compare has no effect on the counter and its clock.
1 = RC Compare resets the counter and starts the counter clock.
• WAVE
0 = Capture Mode is enabled.
1 = Capture Mode is disabled (Waveform Mode is enabled).
• LDRA: RA Loading Selection
LDRA
Edge
0
0
none
0
1
rising edge of TIOA
1
0
falling edge of TIOA
1
1
each edge of TIOA
• LDRB: RB Loading Selection
LDRB
Edge
0
0
none
0
1
rising edge of TIOA
1
0
falling edge of TIOA
1
1
each edge of TIOA
505
1768I–ATARM–09-Jul-09
32.7.5
TC Channel Mode Register: Waveform Mode
Register Name:
TC_CMR
Access Type:
Read/Write
31
30
29
28
BSWTRG
23
22
21
19
AEEVT
14
13
WAVE = 1
7
6
CPCDIS
CPCSTOP
24
BCPB
18
11
ENETRG
5
25
17
16
ACPC
12
WAVSEL
26
BCPC
20
ASWTRG
15
27
BEEVT
4
BURST
ACPA
10
9
EEVT
3
CLKI
8
EEVTEDG
2
1
0
TCCLKS
• TCCLKS: Clock Selection
TCCLKS
Clock Selected
0
0
0
TIMER_CLOCK1
0
0
1
TIMER_CLOCK2
0
1
0
TIMER_CLOCK3
0
1
1
TIMER_CLOCK4
1
0
0
TIMER_CLOCK5
1
0
1
XC0
1
1
0
XC1
1
1
1
XC2
• CLKI: Clock Invert
0 = Counter is incremented on rising edge of the clock.
1 = Counter is incremented on falling edge of the clock.
• BURST: Burst Signal Selection
BURST
0
0
The clock is not gated by an external signal.
0
1
XC0 is ANDed with the selected clock.
1
0
XC1 is ANDed with the selected clock.
1
1
XC2 is ANDed with the selected clock.
• CPCSTOP: Counter Clock Stopped with RC Compare
0 = Counter clock is not stopped when counter reaches RC.
1 = Counter clock is stopped when counter reaches RC.
• CPCDIS: Counter Clock Disable with RC Compare
0 = Counter clock is not disabled when counter reaches RC.
1 = Counter clock is disabled when counter reaches RC.
506
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
• EEVTEDG: External Event Edge Selection
EEVTEDG
Edge
0
0
none
0
1
rising edge
1
0
falling edge
1
1
each edge
• EEVT: External Event Selection
EEVT
Note:
Signal selected as external event
TIOB Direction
0
0
TIOB
input(1)
0
1
XC0
output
1
0
XC1
output
1
1
XC2
output
1. If TIOB is chosen as the external event signal, it is configured as an input and no longer generates waveforms.
• ENETRG: External Event Trigger Enable
0 = The external event has no effect on the counter and its clock. In this case, the selected external event only controls the
TIOA output.
1 = The external event resets the counter and starts the counter clock.
• WAVSEL: Waveform Selection
WAVSEL
Effect
0
0
UP mode without automatic trigger on RC Compare
1
0
UP mode with automatic trigger on RC Compare
0
1
UPDOWN mode without automatic trigger on RC Compare
1
1
UPDOWN mode with automatic trigger on RC Compare
• WAVE = 1
0 = Waveform Mode is disabled (Capture Mode is enabled).
1 = Waveform Mode is enabled.
• ACPA: RA Compare Effect on TIOA
ACPA
Effect
0
0
none
0
1
set
1
0
clear
1
1
toggle
507
1768I–ATARM–09-Jul-09
• ACPC: RC Compare Effect on TIOA
ACPC
Effect
0
0
none
0
1
set
1
0
clear
1
1
toggle
• AEEVT: External Event Effect on TIOA
AEEVT
Effect
0
0
none
0
1
set
1
0
clear
1
1
toggle
• ASWTRG: Software Trigger Effect on TIOA
ASWTRG
Effect
0
0
none
0
1
set
1
0
clear
1
1
toggle
• BCPB: RB Compare Effect on TIOB
BCPB
Effect
0
0
none
0
1
set
1
0
clear
1
1
toggle
• BCPC: RC Compare Effect on TIOB
BCPC
508
Effect
0
0
none
0
1
set
1
0
clear
1
1
toggle
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
• BEEVT: External Event Effect on TIOB
BEEVT
Effect
0
0
none
0
1
set
1
0
clear
1
1
toggle
• BSWTRG: Software Trigger Effect on TIOB
BSWTRG
Effect
0
0
none
0
1
set
1
0
clear
1
1
toggle
509
1768I–ATARM–09-Jul-09
32.7.6
TC Counter Value Register
Register Name:
TC_CV
Access Type:
Read-only
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
CV
7
6
5
4
CV
• CV: Counter Value
CV contains the counter value in real time.
32.7.7
TC Register A
Register Name:
TC_RA
Access Type:
Read-only if WAVE = 0, Read/Write if WAVE = 1
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
RA
7
6
5
4
RA
• RA: Register A
RA contains the Register A value in real time.
510
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
32.7.8
TC Register B
Register Name:
TC_RB
Access Type:
Read-only if WAVE = 0, Read/Write if WAVE = 1
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
RB
7
6
5
4
RB
• RB: Register B
RB contains the Register B value in real time.
32.7.9
TC Register C
Register Name:
TC_RC
Access Type:
Read/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
3
2
1
0
RC
7
6
5
4
RC
• RC: Register C
RC contains the Register C value in real time.
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32.7.10 TC Status Register
Register Name:
TC_SR
Access Type:
Read-only
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
MTIOB
MTIOA
CLKSTA
15
14
13
12
11
10
9
8
–
–
–
–
–
–
–
–
7
6
5
4
3
2
1
0
ETRGS
LDRBS
LDRAS
CPCS
CPBS
CPAS
LOVRS
COVFS
• COVFS: Counter Overflow Status
0 = No counter overflow has occurred since the last read of the Status Register.
1 = A counter overflow has occurred since the last read of the Status Register.
• LOVRS: Load Overrun Status
0 = Load overrun has not occurred since the last read of the Status Register or WAVE = 1.
1 = RA or RB have been loaded at least twice without any read of the corresponding register since the last read of the Status Register, if WAVE = 0.
• CPAS: RA Compare Status
0 = RA Compare has not occurred since the last read of the Status Register or WAVE = 0.
1 = RA Compare has occurred since the last read of the Status Register, if WAVE = 1.
• CPBS: RB Compare Status
0 = RB Compare has not occurred since the last read of the Status Register or WAVE = 0.
1 = RB Compare has occurred since the last read of the Status Register, if WAVE = 1.
• CPCS: RC Compare Status
0 = RC Compare has not occurred since the last read of the Status Register.
1 = RC Compare has occurred since the last read of the Status Register.
• LDRAS: RA Loading Status
0 = RA Load has not occurred since the last read of the Status Register or WAVE = 1.
1 = RA Load has occurred since the last read of the Status Register, if WAVE = 0.
• LDRBS: RB Loading Status
0 = RB Load has not occurred since the last read of the Status Register or WAVE = 1.
1 = RB Load has occurred since the last read of the Status Register, if WAVE = 0.
• ETRGS: External Trigger Status
0 = External trigger has not occurred since the last read of the Status Register.
1 = External trigger has occurred since the last read of the Status Register.
• CLKSTA: Clock Enabling Status
0 = Clock is disabled.
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1 = Clock is enabled.
• MTIOA: TIOA Mirror
0 = TIOA is low. If WAVE = 0, this means that TIOA pin is low. If WAVE = 1, this means that TIOA is driven low.
1 = TIOA is high. If WAVE = 0, this means that TIOA pin is high. If WAVE = 1, this means that TIOA is driven high.
• MTIOB: TIOB Mirror
0 = TIOB is low. If WAVE = 0, this means that TIOB pin is low. If WAVE = 1, this means that TIOB is driven low.
1 = TIOB is high. If WAVE = 0, this means that TIOB pin is high. If WAVE = 1, this means that TIOB is driven high.
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32.7.11 TC Interrupt Enable Register
Register Name:
TC_IER
Access Type:
Write-only
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
ETRGS
LDRBS
LDRAS
CPCS
CPBS
CPAS
LOVRS
COVFS
• COVFS: Counter Overflow
0 = No effect.
1 = Enables the Counter Overflow Interrupt.
• LOVRS: Load Overrun
0 = No effect.
1 = Enables the Load Overrun Interrupt.
• CPAS: RA Compare
0 = No effect.
1 = Enables the RA Compare Interrupt.
• CPBS: RB Compare
0 = No effect.
1 = Enables the RB Compare Interrupt.
• CPCS: RC Compare
0 = No effect.
1 = Enables the RC Compare Interrupt.
• LDRAS: RA Loading
0 = No effect.
1 = Enables the RA Load Interrupt.
• LDRBS: RB Loading
0 = No effect.
1 = Enables the RB Load Interrupt.
• ETRGS: External Trigger
0 = No effect.
1 = Enables the External Trigger Interrupt.
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32.7.12 TC Interrupt Disable Register
Register Name:
TC_IDR
Access Type:
Write-only
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
ETRGS
LDRBS
LDRAS
CPCS
CPBS
CPAS
LOVRS
COVFS
• COVFS: Counter Overflow
0 = No effect.
1 = Disables the Counter Overflow Interrupt.
• LOVRS: Load Overrun
0 = No effect.
1 = Disables the Load Overrun Interrupt (if WAVE = 0).
• CPAS: RA Compare
0 = No effect.
1 = Disables the RA Compare Interrupt (if WAVE = 1).
• CPBS: RB Compare
0 = No effect.
1 = Disables the RB Compare Interrupt (if WAVE = 1).
• CPCS: RC Compare
0 = No effect.
1 = Disables the RC Compare Interrupt.
• LDRAS: RA Loading
0 = No effect.
1 = Disables the RA Load Interrupt (if WAVE = 0).
• LDRBS: RB Loading
0 = No effect.
1 = Disables the RB Load Interrupt (if WAVE = 0).
• ETRGS: External Trigger
0 = No effect.
1 = Disables the External Trigger Interrupt.
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32.7.13 TC Interrupt Mask Register
Register Name:
TC_IMR
Access Type:
Read-only
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
ETRGS
LDRBS
LDRAS
CPCS
CPBS
CPAS
LOVRS
COVFS
• COVFS: Counter Overflow
0 = The Counter Overflow Interrupt is disabled.
1 = The Counter Overflow Interrupt is enabled.
• LOVRS: Load Overrun
0 = The Load Overrun Interrupt is disabled.
1 = The Load Overrun Interrupt is enabled.
• CPAS: RA Compare
0 = The RA Compare Interrupt is disabled.
1 = The RA Compare Interrupt is enabled.
• CPBS: RB Compare
0 = The RB Compare Interrupt is disabled.
1 = The RB Compare Interrupt is enabled.
• CPCS: RC Compare
0 = The RC Compare Interrupt is disabled.
1 = The RC Compare Interrupt is enabled.
• LDRAS: RA Loading
0 = The Load RA Interrupt is disabled.
1 = The Load RA Interrupt is enabled.
• LDRBS: RB Loading
0 = The Load RB Interrupt is disabled.
1 = The Load RB Interrupt is enabled.
• ETRGS: External Trigger
0 = The External Trigger Interrupt is disabled.
1 = The External Trigger Interrupt is enabled.
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33. MultiMedia Card Interface (MCI)
33.1
Description
The MultiMedia Card Interface (MCI) supports the MultiMedia Card (MMC) Specification V2.2
and the SD Memory Card Specification V1.0.
The MCI includes a command register, response registers, data registers, timeout counters and
error detection logic that automatically handle the transmission of commands and, when
required, the reception of the associated responses and data with a limited processor overhead.
The MCI supports stream, block and multi-block data read and write, and is compatible with the
Peripheral DMA Controller (PDC) channels, minimizing processor intervention for large buffer
transfers.
The MCI operates at a rate of up to Master Clock divided by 2 and supports the interfacing of 1
slot(s). Each slot may be used to interface with a MultiMediaCard bus (up to 30 Cards) or with a
SD Memory Card. Only one slot can be selected at a time (slots are multiplexed). A bit field in
the SD Card Register performs this selection.
The SD Memory Card communication is based on a 9-pin interface (clock, command, four data
and three power lines) and the MultiMedia Card on a 7-pin interface (clock, command, one data,
three power lines and one reserved for future use).
The SD Memory Card interface also supports MultiMedia Card operations. The main differences
between SD and MultiMedia Cards are the initialization process and the bus topology.
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1768I–ATARM–09-Jul-09
33.2
Block Diagram
Figure 33-1. Block Diagram
APB Bridge
PDC
APB
MCCK(1)
MCCDA(1)
MCDA0(1)
PMC
MCK
MCDA1(1)
MCDA2(1)
MCDA3(1)
MCI Interface
PIO
MCCDB(1)
MCDB0(1)
MCDB1(1)
MCDB2(1)
Interrupt Control
MCDB3(1)
MCI Interrupt
Note:
520
1. When several MCIs (x MCI) are embedded in a product, MCCK refers to MCIx_CK, MCCDA to MCIx_CDA, MCCDB to
MCIx_CDB,MCDAy to MCIx_DAy, MCDBy to MCIx_DBy.
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33.3
Application Block Diagram
Figure 33-2. Application Block Diagram
Application Layer
ex: File System, Audio, Security, etc.
Physical Layer
MCI Interface
1 2 3 4 5 6 78
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9
SDCard
MMC
33.4
Pin Name List
Table 33-1.
I/O Lines Description
Pin Name(2)
Pin Description
Type(1)
Comments
MCCDA/MCCDB
Command/response
I/O/PP/OD
CMD of an MMC or SDCard
MCCK
Clock
I/O
CLK of an MMC or SD Card
MCDA0 - MCDA3
Data 0..3 of Slot A
I/O/PP
DAT0 of an MMC
DAT[0..3] of an SD Card
MCDB0 - MCDB3
Data 0..3 of Slot B
I/O/PP
DAT0 of an MMC
DAT[0..3] of an SD Card
Notes:
1. I: Input, O: Output, PP: Push/Pull, OD: Open Drain.
2. When several MCI (x MCI) are embedded in a product, MCCK refers to MCIx_CK, MCCDA to MCIx_CDA, MCCDB to
MCIx_CDB, MCDAy to MCIx_DAy, MCDBy to MCIx_DBy.
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33.5
33.5.1
Product Dependencies
I/O Lines
The pins used for interfacing the MultiMedia Cards or SD Cards may be multiplexed with PIO
lines. The programmer must first program the PIO controllers to assign the peripheral functions
to MCI pins.
33.5.2
Power Management
The MCI may be clocked through the Power Management Controller (PMC), so the programmer
must first configure the PMC to enable the MCI clock.
33.5.3
Interrupt
The MCI interface has an interrupt line connected to the Advanced Interrupt Controller (AIC).
Handling the MCI interrupt requires programming the AIC before configuring the MCI.
33.6
Bus Topology
Figure 33-3. Multimedia Memory Card Bus Topology
1234567
MMC
The MultiMedia Card communication is based on a 7-pin serial bus interface. It has three communication lines and four supply lines.
Table 33-2.
Bus Topology
Pin
Number
Name
Type
Description
MCI Pin Name(2)
(Slot z)
1
RSV
NC
Not connected
-
2
CMD
I/O/PP/OD
Command/response
MCCDz
3
VSS1
S
Supply voltage ground
VSS
4
VDD
S
Supply voltage
VDD
5
CLK
I/O
Clock
MCCK
6
VSS2
S
Supply voltage ground
VSS
7
DAT[0]
I/O/PP
Data 0
MCDz0
Notes:
(1)
1. I: Input, O: Output, PP: Push/Pull, OD: Open Drain.
2. When several MCI (x MCI) are embedded in a product, MCCK refers to MCIx_CK, MCCDA to
MCIx_CDA, MCCDB to MCIx_CDB, MCDAy to MCIx_DAy, MCDBy to MCIx_DBy.
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Figure 33-4. MMC Bus Connections (One Slot)
MCI
MCDA0
MCCDA
MCCK
Note:
1234567
1234567
1234567
MMC1
MMC2
MMC3
When several MCIs (x MCI) are embedded in a product, MCCK refers to MCIx_CK, MCCDA to MCIx_CDA MCDAy to
MCIx_DAy.
Figure 33-5. SD Memory Card Bus Topology
1 2 3 4 5 6 78
9
SD CARD
The SD Memory Card bus includes the signals listed in Table 33-3.
Table 33-3.
SD Memory Card Bus Signals
Pin
Number
Name
Type
Description
MCI Pin Name(2)
(Slot z)
1
CD/DAT[3]
I/O/PP
Card detect/ Data line Bit 3
MCDz3
2
CMD
PP
Command/response
MCCDz
3
VSS1
S
Supply voltage ground
VSS
4
VDD
S
Supply voltage
VDD
5
CLK
I/O
Clock
MCCK
6
VSS2
S
Supply voltage ground
VSS
7
DAT[0]
I/O/PP
Data line Bit 0
MCDz0
8
DAT[1]
I/O/PP
Data line Bit 1
MCDz1
9
DAT[2]
I/O/PP
Data line Bit 2
MCDz2
Notes:
(1)
1. I: input, O: output, PP: Push Pull, OD: Open Drain.
2. When several MCIs (x MCI) are embedded in a product, MCCK refers to MCIx_CK, MCCDA to
MCIx_CDA, MCCDB to MCIx_CDB, MCDAy to MCIx_DAy, MCDBy to MCIx_DBy.
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1 2 3 4 5 6 78
Figure 33-6. SD Card Bus Connections with One Slot
MCDA0 - MCDA3
MCCK
9
MCCDA
SD CARD
Note:
When several MCIs (x MCI) are embedded in a product, MCCK refers to MCIx_CK, MCCDA to MCIx_CDA MCDAy to
MCIx_DAy.
1 2 3 4 5 6 78
Figure 33-7. SD Card Bus Connections with Two Slots
MCDA0 - MCDA3
MCCK
1 2 3 4 5 6 78
9
MCCDA
SD CARD 1
MCDB0 - MCDB3
9
MCCDB
SD CARD 2
Note:
When several MCIs (x MCI) are embedded in a product, MCCK refers to MCIx_CK,MCCDA to MCIx_CDA, MCDAy to
MCIx_DAy, MCCDB to MCIx_CDB, MCDBy to MCIx_DBy.
Figure 33-8. Mixing MultiMedia and SD Memory Cards with Two Slots
MCDA0
MCCDA
MCCK
1234567
MMC1
MMC2
MMC3
SD CARD
9
MCCDB
1234567
1 2 3 4 5 6 78
MCDB0 - MCDB3
1234567
Note:
When several MCIs (x MCI) are embedded in a product, MCCK refers to MCIx_CK, MCCDA to MCIx_CDA, MCDAy to
MCIx_DAy, MCCDB to MCIx_CDB, MCDBy to MCIx_DBy.
When the MCI is configured to operate with SD memory cards, the width of the data bus can be
selected in the MCI_SDCR register. Clearing the SDCBUS bit in this register means that the
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width is one bit; setting it means that the width is four bits. In the case of multimedia cards, only
the data line 0 is used. The other data lines can be used as independent PIOs.
33.7
MultiMedia Card Operations
After a power-on reset, the cards are initialized by a special message-based MultiMedia Card
bus protocol. Each message is represented by one of the following tokens:
• Command: A command is a token that starts an operation. A command is sent from the host
either to a single card (addressed command) or to all connected cards (broadcast
command). A command is transferred serially on the CMD line.
• Response: A response is a token which is sent from an addressed card or (synchronously)
from all connected cards to the host as an answer to a previously received command. A
response is transferred serially on the CMD line.
• Data: Data can be transferred from the card to the host or vice versa. Data is transferred via
the data line.
Card addressing is implemented using a session address assigned during the initialization
phase by the bus controller to all currently connected cards. Their unique CID number identifies
individual cards.
The structure of commands, responses and data blocks is described in the MultiMedia-Card
System Specification. See also Table 33-4 on page 526.
MultiMediaCard bus data transfers are composed of these tokens.
There are different types of operations. Addressed operations always contain a command and a
response token. In addition, some operations have a data token; the others transfer their information directly within the command or response structure. In this case, no data token is present
in an operation. The bits on the DAT and the CMD lines are transferred synchronous to the clock
MCI Clock.
Two types of data transfer commands are defined:
• Sequential commands: These commands initiate a continuous data stream. They are
terminated only when a stop command follows on the CMD line. This mode reduces the
command overhead to an absolute minimum.
• Block-oriented commands: These commands send a data block succeeded by CRC bits.
Both read and write operations allow either single or multiple block transmission. A multiple
block transmission is terminated when a stop command follows on the CMD line similarly to the
sequential read.
The MCI provides a set of registers to perform the entire range of MultiMedia Card operations.
33.7.1
Command - Response Operation
After reset, the MCI is disabled and becomes valid after setting the MCIEN bit in the MCI_CR
Control Register.
The PWSEN bit saves power by dividing the MCI clock by 2PWSDIV + 1 when the bus is inactive.
The command and the response of the card are clocked out with the rising edge of the MCI
Clock.
All the timings for MultiMedia Card are defined in the MultiMediaCard System Specification.
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The two bus modes (open drain and push/pull) needed to process all the operations are defined
in the MCI command register. The MCI_CMDR allows a command to be carried out.
For example, to perform an ALL_SEND_CID command:
Host Command
CMD
S
T
Content
CRC
NID Cycles
E
Z
******
CID
Z
S
T
Content
Z
Z
Z
The command ALL_SEND_CID and the fields and values for the MCI_CMDR Control Register
are described in Table 33-4 and Table 33-5.
Table 33-4.
CMD Index
CMD2
Note:
ALL_SEND_CID Command Description
Type
bcr
Argument
[31:0] stuff bits
Resp
R2
Abbreviation
ALL_SEND_CID
Command
Description
Asks all cards to
send their CID
numbers on the
CMD line
bcr means broadcast command with response.
Table 33-5.
Fields and Values for MCI_CMDR Command Register
Field
Value
CMDNB (command number)
2 (CMD2)
RSPTYP (response type)
2 (R2: 136 bits response)
SPCMD (special command)
0 (not a special command)
OPCMD (open drain command)
1
MAXLAT (max latency for command to
response)
0 (NID cycles ==> 5 cycles)
TRCMD (transfer command)
0 (No transfer)
TRDIR (transfer direction)
X (available only in transfer command)
TRTYP (transfer type)
X (available only in transfer command)
The MCI_ARGR contains the argument field of the command.
To send a command, the user must perform the following steps:
• Fill the argument register (MCI_ARGR) with the command argument.
• Set the command register (MCI_CMDR) (see Table 33-5).
The command is sent immediately after writing the command register. The status bit CMDRDY
in the status register (MCI_SR) is asserted when the command is completed. If the command
requires a response, it can be read in the MCI response register (MCI_RSPR). The response
size can be from 48 bits up to 136 bits depending on the command. The MCI embeds an error
detection to prevent any corrupted data during the transfer.
The following flowchart shows how to send a command to the card and read the response if
needed. In this example, the status register bits are polled but setting the appropriate bits in the
interrupt enable register (MCI_IER) allows using an interrupt method.
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Figure 33-9. Command/Response Functional Flow Diagram
Set the command argument
MCI_ARGR = Argument(1)
Set the command
MCI_CMDR = Command
Read MCI_SR
Wait for command
ready status flag
0
CMDRDY
1
Check error bits in the
status register (1)
Yes
Status error flags?
Read response if required
RETURN ERROR(1)
RETURN OK
Note:
33.7.2
1. If the command is SEND_OP_COND, the CRC error flag is always present (refer to R3 response in the MultiMedia Card
specification).
Data Transfer Operation
The MultiMedia Card allows several read/write operations (single block, multiple blocks, stream,
etc.). These kind of transfers can be selected setting the Transfer Type (TRTYP) field in the MCI
Command Register (MCI_CMDR).
These operations can be done using the features of the Peripheral DMA Controller (PDC). If the
PDCMODE bit is set in MCI_MR, then all reads and writes use the PDC facilities.
In all cases, the block length (BLKLEN field) must be defined in the mode register MCI_MR. This
field determines the size of the data block.
33.7.3
Read Operation
The following flowchart shows how to read a single block with or without use of PDC facilities. In
this example (see Figure 33-10), a polling method is used to wait for the end of read. Similarly,
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the user can configure the interrupt enable register (MCI_IER) to trigger an interrupt at the end
of read.
Figure 33-10. Read Functional Flow Diagram
Send SELECT/DESELECT_CARD
(1)
command
to select the card
Send SET_BLOCKLEN command
No
(1)
Yes
Read with PDC
Reset the PDCMODE bit
MCI_MR &= ~PDCMODE
Set the block length (in bytes)
MCI_MR |= (BlockLenght <<16)
Set the PDCMODE bit
MCI_MR |= PDCMODE
Set the block length (in bytes)
MCI_MR |= (BlockLength << 16)
Send READ_SINGLE_BLOCK
command(1)
Configure the PDC channel
MCI_RPR = Data Buffer Address
MCI_RCR = BlockLength/4
MCI_PTCR = RXTEN
Number of words to read = BlockLength/4
Send READ_SINGLE_BLOCK
command(1)
Yes
Number of words to read = 0 ?
Read status register MCI_SR
No
Read status register MCI_SR
Poll the bit
ENDRX = 0?
Poll the bit
RXRDY = 0?
Yes
Yes
No
No
RETURN
Read data = MCI_RDR
Number of words to read =
Number of words to read -1
RETURN
Note:
1. It is assumed that this command has been correctly sent (see Figure 33-9).
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33.7.4
Write Operation
In write operation, the MCI Mode Register (MCI_MR) is used to define the padding value when
writing non-multiple block size. If the bit PDCPADV is 0, then 0x00 value is used when padding
data, otherwise 0xFF is used.
If set, the bit PDCMODE enables PDC transfer.
The following flowchart shows how to write a single block with or without use of PDC facilities
(see Figure 33-11). Polling or interrupt method can be used to wait for the end of write according
to the contents of the Interrupt Mask Register (MCI_IMR).
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Figure 33-11. Write Functional Flow Diagram
Send SELECT/DESELECT_CARD
command(1) to select the card
(1)
Send SET_BLOCKLEN command
Yes
No
Write using PDC
Reset the PDCMODE bit
MCI_MR &= ~PDCMODE
Set the block length
MCI_MR |= (BlockLenght <<16)
Set the PDCMODE bit
MCI_MR |= PDCMODE
Set the block length
MCI_MR |= (BlockLength << 16)
Send WRITE_SINGLE_BLOCK
command(1)
Configure the PDC channel
MCI_TPR = Data Buffer Address to write
MCI_TCR = BlockLength/4
Number of words to write = BlockLength/4
Send WRITE_SINGLE_BLOCK
command(1)
MCI_PTCR = TXTEN
Yes
Number of words to write = 0 ?
Read status register MCI_SR
No
Read status register MCI_SR
Poll the bit
NOTBUSY= 0?
Poll the bit
TXRDY = 0?
Yes
Yes
No
No
RETURN
MCI_TDR = Data to write
Number of words to write =
Number of words to write -1
RETURN
Note:
1. It is assumed that this command has been correctly sent (see Figure 33-9).
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AT91RM9200
The following flowchart shows how to manage a multiple write block transfer with the PDC (see
Figure 33-12). Polling or interrupt method can be used to wait for the end of write according to
the contents of the Interrupt Mask Register (MCI_IMR).
Figure 33-12. Multiple Write Functional Flow Diagram
Send SELECT/DESELECT_CARD
command(1) to select the card
Send SET_BLOCKLEN command(1)
Set the PDCMODE bit
MCI_MR |= PDCMODE
Set the block length
MCI_MR |= (BlockLength << 16)
Configure the PDC channel
MCI_TPR = Data Buffer Address to write
MCI_TCR = BlockLength/4
Send WRITE_MULTIPLE_BLOCK
command(1)
MCI_PTCR = TXTEN
Read status register MCI_SR
Poll the bit
BLKE = 0?
Yes
No
Send STOP_TRANSMISSION
(1)
command
Poll the bit
NOTBUSY = 0?
Yes
No
RETURN
Note:
1. It is assumed that this command has been correctly sent (see Figure 33-9).
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33.8
SD Card Operations
The MultiMedia Card Interface allows processing of SD Memory (Secure Digital Memory Card)
Card commands.
SD cards are based on the Multi Media Card (MMC) format, but are physically slightly thicker
and feature higher data transfer rates, a lock switch on the side to prevent accidental overwriting
and security features. The physical form factor, pin assignment and data transfer protocol are
forward-compatible with the MultiMedia Card with some additions.SD is covered by numerous
patents and trademarks, and licensing is only available through the Secure Digital Card
Association.
The SD Card communication is based on a 9-pin interface (Clock, Command, 4 x Data and 3 x
Power lines). The communication protocol is defined as a part of this specification. The main difference between the SD Card and the MultiMedia Card is the initialization process.
The SD Card Register (MCI_SDCR) allows selection of the Card Slot and the data bus width.
The SD Card bus allows dynamic configuration of the number of data lines. After power up, by
default, the SD Card uses only DAT0 for data transfer. After initialization, the host can change
the bus width (number of active data lines).
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AT91RM9200
33.9
MultiMedia Card Interface (MCI) User Interface
Table 33-6.
Register Mapping
Offset
Register Name
Read/Write
Reset
0x00
Control Register
MCI_CR
Write
–
0x04
Mode Register
MCI_MR
Read/write
0x0
0x08
Data Timeout Register
MCI_DTOR
Read/write
0x0
0x0C
SD Card Register
MCI_SDCR
Read/write
0x0
0x10
Argument Register
MCI_ARGR
Read/write
0x0
0x14
Command Register
MCI_CMDR
Write
–
–
–
–
0x18 - 0x1C
Reserved
0x20
Response Register(1)
MCI_RSPR
Read
0x0
0x24
(1)
MCI_RSPR
Read
0x0
(1)
MCI_RSPR
Read
0x0
(1)
MCI_RSPR
Read
0x0
0x28
Response Register
Response Register
0x2C
Response Register
0x30
Receive Data Register
MCI_RDR
Read
0x0
0x34
Transmit Data Register
MCI_TDR
Write
–
–
–
–
0x38 - 0x3C
Reserved
0x40
Status Register
MCI_SR
Read
0xC0E5
0x44
Interrupt Enable Register
MCI_IER
Write
–
0x48
Interrupt Disable Register
MCI_IDR
Write
–
0x4C
Interrupt Mask Register
MCI_IMR
Read
0x0
Reserved
–
–
–
Reserved for the PDC
–
–
–
0x50-0xFC
0x100-0x124
Note:
Register
1. The response register can be read by N accesses at the same MCI_RSPR or at consecutive addresses (0x20 to 0x2C).
N depends on the size of the response.
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33.9.1
Name:
MCI Control Register
MCI_CR
Access Type:
Write-only
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
SWRST
–
–
–
PWSDIS
PWSEN
MCIDIS
MCIEN
• MCIEN: Multi-Media Interface Enable
0 = No effect.
1 = Enables the Multi-Media Interface if MCDIS is 0.
• MCIDIS: Multi-Media Interface Disable
0 = No effect.
1 = Disables the Multi-Media Interface.
• PWSEN: Power Save Mode Enable
0 = No effect.
1 = Enables the Power Saving Mode if PWSDIS is 0.
Warning: Before enabling this mode, the user must set a value different from 0 in the PWSDIV field (Mode Register
MCI_MR).
• PWSDIS: Power Save Mode Disable
0 = No effect.
1 = Disables the Power Saving Mode.
• SWRST: Software Reset
0 = No effect.
1 = Resets the MCI. A software triggered hardware reset of the MCI interface is performed.
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33.9.2
Name:
MCI Mode Register
MCI_MR
Access Type:
Read/write
31
30
–
–
23
22
29
28
27
26
25
24
18
17
16
0
0
9
8
BLKLEN
21
20
19
BLKLEN
15
14
13
12
11
PDCMODE
PDCPADV
–
–
–
7
6
5
4
10
3
PWSDIV
2
1
0
CLKDIV
• CLKDIV: Clock Divider
Multimedia Card Interface clock (MCCK or MCI_CK) is Master Clock (MCK) divided by (2*(CLKDIV+1)).
• PWSDIV: Power Saving Divider
Multimedia Card Interface clock is divided by 2(PWSDIV) + 1 when entering Power Saving Mode.
Warning: This value must be different from 0 before enabling the Power Save Mode in the MCI_CR (MCI_PWSEN bit).
• PDCPADV: PDC Padding Value
0 = 0x00 value is used when padding data in write transfer (not only PDC transfer).
1 = 0xFF value is used when padding data in write transfer (not only PDC transfer).
• PDCMODE: PDC-oriented Mode
0 = Disables PDC transfer
1 = Enables PDC transfer. In this case, UNRE and OVRE flags in the MCI Mode Register (MCI_SR) are deactivated after
the PDC transfer has been completed.
• BLKLEN: Data Block Length
This field determines the size of the data block.
Bits 16 and 17 must be set to 0.
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33.9.3
Name:
MCI Data Timeout Register
MCI_DTOR
Access Type:
Read/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
–
DTOMUL
DTOCYC
• DTOCYC: Data Timeout Cycle Number
• DTOMUL: Data Timeout Multiplier
These fields determine the maximum number of Master Clock cycles that the MCI waits between two data block transfers.
It equals (DTOCYC x Multiplier).
Multiplier is defined by DTOMUL as shown in the following table:
DTOMUL
Multiplier
0
0
0
1
0
0
1
16
0
1
0
128
0
1
1
256
1
0
0
1024
1
0
1
4096
1
1
0
65536
1
1
1
1048576
If the data time-out set by DTOCYC and DTOMUL has been exceeded, the Data Time-out Error flag (DTOE) in the MCI
Status Register (MCI_SR) raises.
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1768I–ATARM–09-Jul-09
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33.9.4
Name:
MCI SDCard Register
MCI_SDCR
Access Type:
Read/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
–
–
–
–
–
–
–
–
1
7
6
5
4
3
2
SDCBUS
–
–
–
–
–
0
SDCSEL
• SDCSEL: SDCard Slot
SDCSEL
SDCard Slot
0
0
Slot A is selected.
0
1
Slot B is selected
1
0
Reserved
1
1
Reserved
• SDCBUS: SDCard Bus Width
0 = 1-bit data bus
1 = 4-bit data bus
537
1768I–ATARM–09-Jul-09
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33.9.5
Name:
MCI Argument Register
MCI_ARGR
Access Type:
Read/write
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
ARG
23
22
21
20
ARG
15
14
13
12
ARG
7
6
5
4
ARG
• ARG: Command Argument
538
1768I–ATARM–09-Jul-09
AT91RM9200
33.9.6
Name:
MCI Command Register
MCI_CMDR
Access Type:
Write-only
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
18
17
–
–
–
15
14
13
12
11
–
–
–
MAXLAT
OPDCMD
6
5
4
3
7
19
TRTYP
RSPTYP
TRDIR
16
TRCMD
10
9
8
SPCMD
2
1
0
CMDNB
This register is write-protected while CMDRDY is 0 in MCI_SR. If an Interrupt command is sent, this register is only writeable by an interrupt response (field SPCMD). This means that the current command execution cannot be interrupted or
modified.
• CMDNB: Command Number
• RSPTYP: Response Type
RSP
Response Type
0
0
No response.
0
1
48-bit response.
1
0
136-bit response.
1
1
Reserved.
• SPCMD: Special Command
SPCMD
Command
0
0
0
Not a special CMD.
0
0
1
Initialization CMD:
74 clock cycles for initialization sequence.
0
1
0
Synchronized CMD:
Wait for the end of the current data block transfer before sending the
pending command.
0
1
1
Reserved.
1
0
0
Interrupt command:
Corresponds to the Interrupt Mode (CMD40).
1
0
1
Interrupt response:
Corresponds to the Interrupt Mode (CMD40).
• OPDCMD: Open Drain Command
0 = Push pull command
1 = Open drain command
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1768I–ATARM–09-Jul-09
AT91RM9200
• MAXLAT: Max Latency for Command to Response
0 = 5-cycle max latency
1 = 64-cycle max latency
• TRCMD: Transfer Command
TRCMD
Transfer Type
0
0
No data transfer
0
1
Start data transfer
1
0
Stop data transfer
1
1
Reserved
• TRDIR: Transfer Direction
0 = Write
1 = Read
• TRTYP: Transfer Type
TRTYP
Transfer Type
0
0
0
MMC/SDCard Single Block
0
0
1
MMC/SDCard Multiple Block
0
1
0
MMC Stream
0
1
1
Reserved
540
1768I–ATARM–09-Jul-09
AT91RM9200
33.9.7
Name:
MCI Response Register
MCI_RSPR
Access Type:
31
Read-only
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
RSP
23
22
21
20
RSP
15
14
13
12
RSP
7
6
5
4
RSP
• RSP: Response
Note:
1. The response register can be read by N accesses at the same MCI_RSPR or at consecutive addresses (0x20 to 0x2C).
N depends on the size of the response.
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1768I–ATARM–09-Jul-09
AT91RM9200
33.9.8
Name:
MCI Receive Data Register
MCI_RDR
Access Type:
31
Read-only
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
DATA
23
22
21
20
DATA
15
14
13
12
DATA
7
6
5
4
DATA
• DATA: Data to Read
33.9.9
Name:
MCI Transmit Data Register
MCI_TDR
Access Type:
31
Write-only
30
29
28
DATA
23
22
21
20
DATA
15
14
13
12
DATA
7
6
5
4
DATA
• DATA: Data to Write
542
1768I–ATARM–09-Jul-09
AT91RM9200
33.9.10
Name:
MCI Status Register
MCI_SR
Access Type:
Read-only
31
30
29
28
27
26
25
24
UNRE
OVRE
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
DTOE
DCRCE
RTOE
RENDE
RCRCE
RDIRE
RINDE
15
14
13
12
11
10
9
8
TXBUFE
RXBUFF
–
–
–
–
SDIOIRQB
SDIOIRQA
7
6
5
4
3
2
1
0
ENDTX
ENDRX
NOTBUSY
DTIP
BLKE
TXRDY
RXRDY
CMDRDY
• CMDRDY: Command Ready
0 = A command is in progress.
1 = The last command has been sent. Cleared when writing in the MCI_CMDR.
• RXRDY: Receiver Ready
0 = Data has not yet been received since the last read of MCI_RDR.
1 = Data has been received since the last read of MCI_RDR.
• TXRDY: Transmit Ready
0= The last data written in MCI_TDR has not yet been transferred in the Shift Register.
1= The last data written in MCI_TDR has been transferred in the Shift Register.
• BLKE: Data Block Ended
This flag must be used only for Write Operations.
0 = A data block transfer is not yet finished. Cleared when reading the MCI_SR.
1 = A data block transfer has ended, including the CRC16 Status transmission.
In PDC mode (PDCMODE=1), the flag is set when the CRC Status of the last block has been transmitted (TXBUFE already
set).
Otherwise (PDCMODE=0), the flag is set for each transmitted CRC Status.
Refer to the MMC or SD Specification for more details concerning the CRC Status.
• DTIP: Data Transfer in Progress
0 = No data transfer in progress.
1 = The current data transfer is still in progress, including CRC16 calculation. Cleared at the end of the CRC16 calculation.
• NOTBUSY: MCI Not Busy
This flag must be used only for Write Operations.
A block write operation uses a simple busy signalling of the write operation duration on the data (DAT0) line: during a data
transfer block, if the card does not have a free data receive buffer, the card indicates this condition by pulling down the data
line (DAT0) to LOW. The card stops pulling down the data line as soon as at least one receive buffer for the defined data
transfer block length becomes free.
543
1768I–ATARM–09-Jul-09
AT91RM9200
The NOTBUSY flag allows to deal with these different states.
0 = The MCI is not ready for new data transfer. Cleared at the end of the card response.
1 = The MCI is ready for new data transfer. Set when the busy state on the data line has ended. This corresponds to a free
internal data receive buffer of the card.
Refer to the MMC or SD Specification for more details concerning the busy behavior.
• ENDRX: End of RX Buffer
0 = The Receive Counter Register has not reached 0 since the last write in MCI_RCR or MCI_RNCR.
1 = The Receive Counter Register has reached 0 since the last write in MCI_RCR or MCI_RNCR.
• ENDTX: End of TX Buffer
0 = The Transmit Counter Register has not reached 0 since the last write in MCI_TCR or MCI_TNCR.
1 = The Transmit Counter Register has reached 0 since the last write in MCI_TCR or MCI_TNCR.
Note:
BLKE and NOTBUSY flags can be used to check that the data has been successfully transmitted on the data lines and not only
transferred from the PDC to the MCI Controller.
• RXBUFF: RX Buffer Full
0 = MCI_RCR or MCI_RNCR has a value other than 0.
1 = Both MCI_RCR and MCI_RNCR have a value of 0.
• TXBUFE: TX Buffer Empty
0 = MCI_TCR or MCI_TNCR has a value other than 0.
1 = Both MCI_TCR and MCI_TNCR have a value of 0.
Note:
BLKE and NOTBUSY flags can be used to check that the data has been successfully transmitted on the data lines and not only
transferred from the PDC to the MCI Controller.
• RINDE: Response Index Error
0 = No error.
1 = A mismatch is detected between the command index sent and the response index received. Cleared when writing in
the MCI_CMDR.
• RDIRE: Response Direction Error
0 = No error.
1 = The direction bit from card to host in the response has not been detected.
• RCRCE: Response CRC Error
0 = No error.
1 = A CRC7 error has been detected in the response. Cleared when writing in the MCI_CMDR.
• RENDE: Response End Bit Error
0 = No error.
1 = The end bit of the response has not been detected. Cleared when writing in the MCI_CMDR.
• RTOE: Response Time-out Error
544
1768I–ATARM–09-Jul-09
AT91RM9200
0 = No error.
1 = The response time-out set by MAXLAT in the MCI_CMDR has been exceeded. Cleared when writing in the
MCI_CMDR.
• DCRCE: Data CRC Error
0 = No error.
1 = A CRC16 error has been detected in the last data block. Reset by reading in the MCI_SR register.
• DTOE: Data Time-out Error
0 = No error.
1 = The data time-out set by DTOCYC and DTOMUL in MCI_DTOR has been exceeded. Reset by reading in the MCI_SR
register.
• OVRE: Overrun
0 = No error.
1 = At least one 8-bit received data has been lost (not read). Cleared when sending a new data transfer command.
• UNRE: Underrun
0 = No error.
1 = At least one 8-bit data has been sent without valid information (not written). Cleared when sending a new data transfer
command.
• RXBUFF: RX Buffer Full
0 = MCI_RCR or MCI_RNCR has a value other than 0.
1 = Both MCI_RCR and MCI_RNCR have a value of 0.
• TXBUFE: TX Buffer Empty
0 = MCI_TCR or MCI_TNCR has a value other than 0.
1 = Both MCI_TCR and MCI_TNCR have a value of 0.
545
1768I–ATARM–09-Jul-09
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33.9.11
Name:
MCI Interrupt Enable Register
MCI_IER
Access Type:
Write-only
31
30
29
28
27
26
25
24
UNRE
OVRE
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
DTOE
DCRCE
RTOE
RENDE
RCRCE
RDIRE
RINDE
15
14
13
12
11
10
9
8
TXBUFE
RXBUFF
–
–
–
–
SDIOIRQB
SDIOIRQA
7
6
5
4
3
2
1
0
ENDTX
ENDRX
NOTBUSY
DTIP
BLKE
TXRDY
RXRDY
CMDRDY
• CMDRDY: Command Ready Interrupt Enable
• RXRDY: Receiver Ready Interrupt Enable
• TXRDY: Transmit Ready Interrupt Enable
• BLKE: Data Block Ended Interrupt Enable
• DTIP: Data Transfer in Progress Interrupt Enable
• NOTBUSY: Data Not Busy Interrupt Enable
• ENDRX: End of Receive Buffer Interrupt Enable
• ENDTX: End of Transmit Buffer Interrupt Enable
• RXBUFF: Receive Buffer Full Interrupt Enable
• TXBUFE: Transmit Buffer Empty Interrupt Enable
• RINDE: Response Index Error Interrupt Enable
• RDIRE: Response Direction Error Interrupt Enable
• RCRCE: Response CRC Error Interrupt Enable
• RENDE: Response End Bit Error Interrupt Enable
• RTOE: Response Time-out Error Interrupt Enable
• DCRCE: Data CRC Error Interrupt Enable
• DTOE: Data Time-out Error Interrupt Enable
• OVRE: Overrun Interrupt Enable
• UNRE: UnderRun Interrupt Enable
0 = No effect.
546
1768I–ATARM–09-Jul-09
AT91RM9200
1 = Enables the corresponding interrupt.
547
1768I–ATARM–09-Jul-09
AT91RM9200
33.9.12
Name:
MCI Interrupt Disable Register
MCI_IDR
Access Type:
Write-only
31
30
29
28
27
26
25
24
UNRE
OVRE
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
DTOE
DCRCE
RTOE
RENDE
RCRCE
RDIRE
RINDE
15
14
13
12
11
10
9
8
TXBUFE
RXBUFF
–
–
–
–
SDIOIRQB
SDIOIRQA
7
6
5
4
3
2
1
0
ENDTX
ENDRX
NOTBUSY
DTIP
BLKE
TXRDY
RXRDY
CMDRDY
• CMDRDY: Command Ready Interrupt Disable
• RXRDY: Receiver Ready Interrupt Disable
• TXRDY: Transmit Ready Interrupt Disable
• BLKE: Data Block Ended Interrupt Disable
• DTIP: Data Transfer in Progress Interrupt Disable
• NOTBUSY: Data Not Busy Interrupt Disable
• ENDRX: End of Receive Buffer Interrupt Disable
• ENDTX: End of Transmit Buffer Interrupt Disable
• RXBUFF: Receive Buffer Full Interrupt Disable
• TXBUFE: Transmit Buffer Empty Interrupt Disable
• RINDE: Response Index Error Interrupt Disable
• RDIRE: Response Direction Error Interrupt Disable
• RCRCE: Response CRC Error Interrupt Disable
• RENDE: Response End Bit Error Interrupt Disable
• RTOE: Response Time-out Error Interrupt Disable
• DCRCE: Data CRC Error Interrupt Disable
• DTOE: Data Time-out Error Interrupt Disable
• OVRE: Overrun Interrupt Disable
• UNRE: UnderRun Interrupt Disable
0 = No effect.
548
1768I–ATARM–09-Jul-09
AT91RM9200
1 = Disables the corresponding interrupt.
549
1768I–ATARM–09-Jul-09
33.9.13
Name:
MCI Interrupt Mask Register
MCI_IMR
Access Type:
Read-only
31
30
29
28
27
26
25
24
UNRE
OVRE
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
DTOE
DCRCE
RTOE
RENDE
RCRCE
RDIRE
RINDE
15
14
13
12
11
10
9
8
TXBUFE
RXBUFF
–
–
–
–
SDIOIRQB
SDIOIRQA
7
6
5
4
3
2
1
0
ENDTX
ENDRX
NOTBUSY
DTIP
BLKE
TXRDY
RXRDY
CMDRDY
• CMDRDY: Command Ready Interrupt Mask
• RXRDY: Receiver Ready Interrupt Mask
• TXRDY: Transmit Ready Interrupt Mask
• BLKE: Data Block Ended Interrupt Mask
• DTIP: Data Transfer in Progress Interrupt Mask
• NOTBUSY: Data Not Busy Interrupt Mask
• ENDRX: End of Receive Buffer Interrupt Mask
• ENDTX: End of Transmit Buffer Interrupt Mask
• RXBUFF: Receive Buffer Full Interrupt Mask
• TXBUFE: Transmit Buffer Empty Interrupt Mask
• RINDE: Response Index Error Interrupt Mask
• RDIRE: Response Direction Error Interrupt Mask
• RCRCE: Response CRC Error Interrupt Mask
• RENDE: Response End Bit Error Interrupt Mask
• RTOE: Response Time-out Error Interrupt Mask
• DCRCE: Data CRC Error Interrupt Mask
• DTOE: Data Time-out Error Interrupt Mask
• OVRE: Overrun Interrupt Mask
• UNRE: UnderRun Interrupt Mask
0 = The corresponding interrupt is not enabled.
550
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
1 = The corresponding interrupt is enabled.
551
1768I–ATARM–09-Jul-09
552
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
34. USB Device Port (UDP)
34.1
Overview
The USB Device Port (UDP) is compliant with the Universal Serial Bus (USB) V2.0 full-speed
device specification.
Each endpoint is associated with one or two banks of a dual-port RAM used to store the current
data payload. If two banks are used, one DPR bank is read or written by the processor, while the
other is read or written by the USB device peripheral. This feature is mandatory for isochronous
endpoints. Thus the device maintains the maximum bandwidth (1M bytes/s) by working with
endpoints with two banks of DPR.
Suspend and resume are automatically detected by the USB device, which notifies the processor by raising an interrupt. Depending on the product, an external signal can be used to send a
wake-up to the USB host controller.
The main features of the UDP are:
• USB V2.0 Full-speed Compliant, 12 Mbits per second
• Embedded USB V2.0 Full-speed Transceiver
• Embedded Dual-port RAM for Endpoints
• Suspend/Resume Logic
• Ping-pong Mode (2 Memory Banks) for Isochronous and Bulk Endpoints
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34.2
Block Diagram
Figure 34-1. USB Device Port Block Diagram
Atmel Bridge
MCK
APB
to
MCU
Bus
UDPCK
USB Device
txoen
U
s
e
r
I
n
t
e
r
f
a
c
e
udp_int
W
r
a
p
p
e
r
FIFO
eopn
Serial
Interface
Engine
12 MHz
SIE
txd
rxdm
Embedded
USB
Transceiver
DP
DM
rxd
rxdp
Suspend/Resume Logic
Master Clock
Domain
External Resume
Dual
Port
RAM
W
r
a
p
p
e
r
Recovered 12 MHz
Domain
Access to the UDP is via the APB bus interface. Read and write to the data FIFO are done by
reading and writing 8-bit values to APB registers.
The UDP peripheral requires two clocks: one peripheral clock used by the MCK domain and a
48 MHz clock used by the 12 MHz domain.
A USB 2.0 full-speed pad is embedded and controlled by the SIE.
The signal external_resume is optional. It allows the UDP peripheral to wake-up once in system
mode. The host will then be notified that the device asks for a resume. This optional feature
must be also negotiated with the host during the enumeration.
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34.3
Product Dependencies
The USB physical transceiver is integrated into the product. The bi-directional differential signals
DP and DM are available from the product boundary.
Two I/O lines may be used by the application:
• One to check that VBUS is still available from the host. Self-powered devices may use this
entry to be notified that the host has been powered off. In this case, the board pull-up on DP
must be disabled in order to prevent feeding current to the host.
• One to control the board pull-up on DP. Thus, when the device is ready to communicate with
the host, it activates its DP pull-up through this control line.
34.3.1
I/O Lines
DP and DM are not controlled by any PIO controllers. The embedded USB physical transceiver
is controlled by the USB device peripheral.
To reserve an I/O line to check VBUS, the programmer must first program the PIO controller to
assign this I/O in input PIO mode.
To reserve an I/O line to control the board pull-up, the programmer must first program the PIO
controller to assign this I/O in output PIO mode.
34.3.2
Power Management
The USB device peripheral requires a 48 MHz clock. This clock must be generated by a PLL
with an accuracy of ± 0.25%.
Thus, the USB device receives two clocks from the Power Management Controller (PMC): the
master clock, MCK, used to drive the peripheral user interface and the UDPCK used to interface
with the bus USB signals (recovered 12 MHz domain).
34.3.3
Interrupt
The USB device interface has an interrupt line connected to the Advanced Interrupt Controller
(AIC).
Handling the USB device interrupt requires programming the AIC before configuring the UDP.
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34.4
Typical Connection
Figure 34-2. Board Schematic to Interface USB Device Peripheral
PAm
UDP_CNX
22 kΩ
15 kΩ
3V3
1.5 kΩ
47 kΩ
PAn
UDP_PUP
System
Reset
33 pF
27Ω
DM
2
1
100 nF
DP
27Ω
15 pF
3
Type B
4
Connector
15 pF
UDP_CNX is an input signal used to check if the host is connected
UDP_PUP is an output signal used to enable pull-up on DP.
Figure 34-2 shows automatic activation of pull-up after reset.
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34.5
Functional Description
34.5.1
USB V2.0 Full-speed Introduction
The USB V2.0 full-speed provides communication services between host and attached USB
devices. Each device is offered with a collection of communication flows (pipes) associated with
each endpoint. Software on the host communicates with an USB device through a set of communication flows.
Figure 34-3. Example of USB V2.0 Full-speed Communication Control
USB Host V1.1
Software Client 1
Software Client 2
Data Flow: Control Transfer
Data Flow: Isochronous In Transfer
Data Flow: Isochronous Out Transfer
Data Flow: Control Transfer
EP0
EP1
USB Device 1.1
Block 1
EP2
EP0
Data Flow: Bulk In Transfer
EP4
Data Flow: Bulk Out Transfer
USB Device 1.1
Block 2
EP5
34.5.1.1
USB V2.0 Full-speed Transfer Types
A communication flow is carried over one of four transfer types defined by the USB device.
Table 34-1.
USB Communication Flow
Transfer
Direction
Bandwidth
Supported Endpoint Size
Error Detection
Retrying
Bi-directional
Not guaranteed
8
Yes
Automatic
Isochronous
Uni-directional
Guaranteed
1 - 1023
Yes
No
Interrupt
Uni-directional
Not guaranteed
≤256
Yes
Yes
Bulk
Uni-directional
Not guaranteed
8, 16, 32, 64
Yes
Yes
Control
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34.5.1.2
USB Bus Transactions
Each transfer results in one or more transactions over the USB bus. There are five kinds of
transactions flowing across the bus in packets:
1. Setup Transaction
2. Data IN Transaction
3. Data OUT Transaction
4. Status IN Transaction
5. Status OUT Transaction
34.5.1.3
USB Transfer Event Definitions
As shown in Table 34-2, transfers are sequential events carried out on the USB bus.
Table 34-2.
USB Transfer Events
• Setup transaction > Data IN transactions >
Status OUT transaction
Control Transfers(1) (3)
Interrupt IN Transfer
(device toward host)
• Setup transaction > Data OUT transactions >
Status IN transaction
• Setup transaction > Status IN transaction
• Data IN transaction > Data IN transaction
Interrupt OUT Transfer
(host toward device)
• Data OUT transaction > Data OUT transaction
Isochronous IN Transfer(2)
(device toward host)
• Data IN transaction > Data IN transaction
Isochronous OUT Transfer(2)
(host toward device)
• Data OUT transaction > Data OUT transaction
Bulk IN Transfer
(device toward host)
• Data IN transaction > Data IN transaction
Bulk OUT Transfer
(host toward device)
• Data OUT transaction > Data OUT transaction
Notes:
1. Control transfer must use endpoints with no ping-pong attributes.
2. Isochronous transfers must use endpoints with ping-pong attributes.
3. Control transfers can be aborted using a stall handshake.
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34.5.2
34.5.2.1
Handling Transactions with USB V2.0 Device Peripheral
Setup Transaction
Setup is a special type of host-to-device transaction used during control transfers. Control transfers must be performed using endpoints with no ping-pong attributes. A setup transaction needs
to be handled as soon as possible by the firmware. It is used to transmit requests from the host
to the device. These requests are then handled by the USB device and may require more arguments. The arguments are sent to the device by a Data OUT transaction which follows the setup
transaction. These requests may also return data. The data is carried out to the host by the next
Data IN transaction which follows the setup transaction. A status transaction ends the control
transfer.
When a setup transfer is received by the USB endpoint:
• The USB device automatically acknowledges the setup packet
• RXSETUP is set in the UDP_CSRx register
• An endpoint interrupt is generated while the RXSETUP is not cleared. This interrupt is
carried out to the microcontroller if interrupts are enabled for this endpoint.
Thus, firmware must detect the RXSETUP polling the UDP_CSRx or catching an interrupt, read
the setup packet in the FIFO, then clear the RXSETUP. RXSETUP cannot be cleared before the
setup packet has been read in the FIFO. Otherwise, the USB device would accept the next Data
OUT transfer and overwrite the setup packet in the FIFO.
Figure 34-4. Setup Transaction Followed by a Data OUT Transaction
Setup Received
USB
Bus Packets
Setup
PID
Data Setup
Setup Handled by Firmware
ACK
PID
RXSETUP Flag
Data OUT
PID
Data OUT
Data OUT
PID
Data OUT
ACK
PID
Cleared by Firmware
Set by USB
Device Peripheral
RX_Data_BKO
(USB_CSRx)
34.5.2.2
NAK
PID
Interrupt Pending
Set by USB Device
FIFO (DPR)
Content
Data Out Received
XX
Data Setup
XX
Data OUT
Data IN Transaction
Data IN transactions are used in control, isochronous, bulk and interrupt transfers and conduct
the transfer of data from the device to the host. Data IN transactions in isochronous transfer
must be done using endpoints with ping-pong attributes.
Using Endpoints Without Ping-pong Attributes
To perform a Data IN transaction, using a non ping-pong endpoint:
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1. The microcontroller checks if it is possible to write in the FIFO by polling TXPKTRDY in
the endpoint’s UDP_CSRx register (TXPKTRDY must be cleared).
2. The microcontroller writes data to be sent in the endpoint’s FIFO, writing zero or more
byte values in the endpoint’s UDP_FDRx register,
3. The microcontroller notifies the USB peripheral it has finished by setting the TXPKTRDY in the endpoint’s UDP_CSRx register,
4. The microcontroller is notified that the endpoint’s FIFO has been released by the USB
device when TXCOMP in the endpoint’s UDP_CSRx register has been set. Then an
interrupt for the corresponding endpoint is pending while TXCOMP is set.
TXCOMP is set by the USB device when it has received an ACK PID signal for the Data IN
packet. An interrupt is pending while TXCOMP is set.
Note:
Please refer to Chapter 8 of the Universal Serial Bus Specification, Rev 1.1, for more information
on the Data IN protocol layer.
Figure 34-5. Data IN Transfer for Non Ping-pong Endpoint
Prevous Data IN TX
USB Bus Packets
Data IN
PID
Data IN 1
Microcontroller Load Data in FIFO
Data IN
PID
ACK
PID
NAK
PID
Data IN
PID
Data is Sent on USB Bus
Data IN 2
ACK
PID
TXPKTRDY Flag
(USB_CSRx)
Set by the Firmware
Data Payload Written in FIFO
Cleared by USB Device
Interrupt Pending
TXCOMP Flag
(USB_CSRx)
FIFO (DPR)
Content
560
Cleared by Firmware
Data IN 1
Load In Progress
Interrupt Pending
Start to Write Data
Payload in FIFO
Data IN 2
Load In
Progress
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Using Endpoints With Ping-pong Attribute
The use of an endpoint with ping-pong attributes is necessary during isochronous transfer. To
be able to guarantee a constant bandwidth, the microcontroller must prepare the next data payload to be sent while the current one is being sent by the USB device. Thus two banks of
memory are used. While one is available for the microcontroller, the other one is locked by the
USB device.
Figure 34-6. Bank Swapping Data IN Transfer for Ping-pong Endpoints
1st Data Payload
USB Bus
USB Device
Microcontroller
Write
Bank 0
Endpoint 1
Read
Read and Write at the Same Time
2nd Data Payload
Data IN Packet
Bank 1
Endpoint 1
Bank 0
Endpoint 1
1st Data Payload
Bank 0
Endpoint 1
Bank 1
Endpoint 1
2nd Data Payload
3rd Data Payload
Bank 0
Endpoint 1
Data IN Packet
Data IN Packet
3rd Data Payload
When using a ping-pong endpoint, the following procedures are required to perform Data IN
transactions:
1. The microcontroller checks if it is possible to write in the FIFO by polling TXPKTRDY to
be cleared in the endpoint’s UDP_CSRx register.
2. The microcontroller writes the first data payload to be sent in the FIFO (Bank 0), writing
zero or more byte values in the endpoint’s UDP_FDRx register.
3. The microcontroller notifies the USB peripheral it has finished writing in Bank 0 of the
FIFO by setting the TXPKTRDY in the endpoint’s UDP_CSRx register.
4. Without waiting for TXPKTRDY to be cleared, the microcontroller writes the second
data payload to be sent in the FIFO (Bank 1), writing zero or more byte values in the
endpoint’s UDP_FDRx register.
5. The microcontroller is notified that the first Bank has been released by the USB device
when TXCOMP in the endpoint’s UDP_CSRx register is set. An interrupt is pending
while TXCOMP is being set.
6. Once the microcontroller has received TXCOMP for the first Bank, it notifies the USB
device that it has prepared the second Bank to be sent rising TXPKTRDY in the endpoint’s UDP_CSRx register.
7. At this step, Bank 0 is available and the microcontroller can prepare a third data payload to be sent.
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Figure 34-7. Data IN Transfer for Ping-pong Endpoint
Microcontroller
Load Data IN Bank 0
USB Bus
Packets
Data IN
PID
TXPKTRDY Flag
(USB_MCSRx)
Microcontroller Load Data IN Bank 1
USB Device Send Bank 0
ACK
PID
Data IN
Microcontroller Load Data IN Bank 0
USB Device Send Bank 1
Data IN
PID
Cleared by USB Device,
Data Payload Fully Transmitted
Set by Firmware,
Data Payload Written in FIFO Bank 0
Set by Firmware,
Data Payload Written in FIFO Bank 1
Interrupt Pending
Set by USB
Device
TXCOMP Flag
(USB_CSRx)
ACK
PID
Data IN
Set by USB Device
Interrupt Cleared by Firmware
FIFO (DPR) Written by
Microcontroller
Bank 0
FIFO (DPR)
Bank 1
Read by USB Device
Written by
Microcontroller
Written by
Microcontroller
Read by USB Device
Warning: There is software critical path due to the fact that once the second bank is filled, the
driver has to wait for TX_COMP to set TX_PKTRDY. If the delay between receiving TX_COMP
is set and TX_PKTRDY is set is too long, some Data IN packets may be NACKed, reducing the
bandwidth.
34.5.2.3
Data OUT Transaction
Data OUT transactions are used in control, isochronous, bulk and interrupt transfers and conduct the transfer of data from the host to the device. Data OUT transactions in isochronous
transfers must be done using endpoints with ping-pong attributes.
Data OUT Transaction Without Ping-pong Attributes
To perform a Data OUT transaction, using a non ping-pong endpoint:
1. The host generates a Data OUT packet.
2. This packet is received by the USB device endpoint. While the FIFO associated to this
endpoint is being used by the microcontroller, a NAK PID is returned to the host. Once
the FIFO is available, data are written to the FIFO by the USB device and an ACK is
automatically carried out to the host.
3. The microcontroller is notified that the USB device has received a data payload polling
RX_DATA_BK0 in the endpoint’s UDP_CSRx register. An interrupt is pending for this
endpoint while RX_DATA_BK0 is set.
4. The number of bytes available in the FIFO is made available by reading RXBYTECNT
in the endpoint’s UDP_CSRx register.
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5. The microcontroller carries out data received from the endpoint’s memory to its memory. Data received is available by reading the endpoint’s UDP_FDRx register.
6. The microcontroller notifies the USB device that it has finished the transfer by clearing
RX_DATA_BK0 in the endpoint’s UDP_CSRx register.
7. A new Data OUT packet can be accepted by the USB device.
Figure 34-8. Data OUT Transfer for Non Ping-pong Endpoints
USB Bus
Packets
Host Sends Data Payload
Microcontroller Transfers Data
Host Sends the Next Data Payload
Data OUT
PID
ACK
PID
Data OUT 1
RX_DATA_BK0
(USB_CSRx)
Data OUT2 Data OUT2 NAK
PID
PID
Host Resends the Next Data Payload
Data OUT
PID
Data OUT2
ACK
PID
Interrupt Pending
Set by USB Device
FIFO (DPR)
Content
Data OUT 1
Written by USB Device
Data OUT 1
Microcontroller Read
Cleared by Firmware,
Data Payload Written in FIFO
Data OUT 2
Written by USB Device
An interrupt is pending while the flag RX_DATA_BK0 is set. Memory transfer between the USB
device, the FIFO and microcontroller memory can not be done after RX_DATA_BK0 has been
cleared. Otherwise, the USB device would accept the next Data OUT transfer and overwrite the
current Data OUT packet in the FIFO.
Using Endpoints With
Ping-pong Attributes
During isochronous transfer, using an endpoint with ping-pong attributes is necessary. To be
able to guarantee a constant bandwidth, the microcontroller must read the previous data payload sent by the host, while the current data payload is received by the USB device. Thus two
banks of memory are used. While one is available for the microcontroller, the other one is locked
by the USB device.
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Figure 34-9. Bank Swapping in Data OUT Transfers for Ping-pong Endpoints
USB Bus
USB Device
Microcontroller
Write
Write and Read at the Same Time
Read
1st Data Payload
Bank 1
Endpoint 1
Data IN Packet
nd
2 Data Payload
Bank 0
Endpoint 1
3rd Data Payload
1st Data Payload
Bank 0
Endpoint 1
2nd Data Payload
Bank 1
Endpoint 1
Data IN Packet
Bank 0
Endpoint 1
Data IN Packet
3rd Data Payload
Bank 0
Endpoint 1
When using a ping-pong endpoint, the following procedures are required to perform Data OUT
transactions:
1. The host generates a Data OUT packet.
2. This packet is received by the USB device endpoint. It is written in the endpoint’s FIFO
Bank 0.
3. The USB device sends an ACK PID packet to the host. The host can immediately send
a second Data OUT packet. It is accepted by the device and copied to FIFO Bank 1.
4. The microcontroller is notified that the USB device has received a data payload, polling
RX_DATA_BK0 in the endpoint’s UDP_CSRx register. An interrupt is pending for this
endpoint while RX_DATA_BK0 is set.
5. The number of bytes available in the FIFO is made available by reading RXBYTECNT
in the endpoint’s UDP_CSRx register.
6. The microcontroller transfers out data received from the endpoint’s memory to the
microcontroller’s memory. Data received is made available by reading the endpoint’s
UDP_FDRx register.
7. The microcontroller notifies the USB peripheral device that it has finished the transfer
by clearing RX_DATA_BK0 in the endpoint’s UDP_CSRx register.
8. A third Data OUT packet can be accepted by the USB peripheral device and copied in
the FIFO Bank 0.
9. If a second Data OUT packet has been received, the microcontroller is notified by the
flag RX_DATA_BK1 set in the endpoint’s UDP_CSRx register. An interrupt is pending
for this endpoint while RX_DATA_BK1 is set.
10. The microcontroller transfers out data received from the endpoint’s memory to the
microcontroller’s memory. Data received is available by reading the endpoint’s
UDP_FDRx register.
11. The microcontroller notifies the USB device it has finished the transfer by clearing
RX_DATA_BK1 in the endpoint’s UDP_CSRx register.
12. A fourth Data OUT packet can be accepted by the USB device and copied in the FIFO
Bank 0.
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Figure 34-10. Data OUT Transfer for Ping-pong Endpoint
Microcontroller Reads Data 1 in Bank 0,
Host Sends Second Data Payload
Host Sends First Data Payload
USB Bus
Packets
Data OUT
PID
RX_DATA_BK0 Flag
(USB_CSRx)
Data OUT 1
Data OUT
PID
Data OUT 2
Set by USB Device,
Data Payload Written
in FIFO Endpoint Bank 0
Data OUT1
Write by USB Device
FIFO (DPR)
Bank 1
ACK
PID
Set by USB Device,
Data Payload Written
in FIFO Endpoint Bank 1
Data OUT 3
A
P
Cleared by Firmware
Interrupt Pending
Data OUT 1
Data OUT 3
Read By Microcontroller
Write In Progress
Data OUT 2
Write by USB Device
Note:
Data OUT
PID
Cleared by Firmware
Interrupt Pending
RX_DATA_BK1 Flag
(USB_CSRx)
FIFO (DPR)
Bank 0
ACK
PID
Microcontroller Reads Data2 in Bank 1,
Host Sends Third Data Payload
Data OUT 2
Read By Microcontroller
An interrupt is pending while the RX_DATA_BK0 or RX_DATA_BK1 flag is set.
Warning: When RX_DATA_BK0 and RX_DATA_BK1 are both set, there is no way to determine
which one to clear first. Thus the software must keep an internal counter to be sure to clear alternatively RX_DATA_BK0 then RX_DATA_BK1. This situation may occur when the software
application is busy elsewhere and the two banks are filled by the USB host. Once the application
comes back to the USB driver, the two flags are set.
34.5.2.4
Status Transaction
A status transaction is a special type of host to device transaction used only in a control transfer.
The control transfer must be performed using endpoints with no ping-pong attributes. According
to the control sequence (read or write), the USB device sends or receives a status transaction.
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Figure 34-11. Control Read and Write Sequences
Setup Stage
Control Read
Setup TX
Setup Stage
Control Write
No Data
Control
Notes:
Setup TX
Data Stage
Data OUT TX
Status Stage
Data OUT TX
Data Stage
Data IN TX
Setup Stage
Status Stage
Setup TX
Status IN TX
Data IN TX
Status IN TX
Status Stage
Status OUT TX
1. During the Status IN stage, the host waits for a zero length packet (Data IN transaction with no
data) from the device using DATA1 PID. Please refer to Chapter 8 of the Universal Serial Bus
Specification, Rev. 1.1, to get more information on the protocol layer.
2. During the Status OUT stage, the host emits a zero length packet to the device (Data OUT
transaction with no data).
34.5.2.5
Status IN Transfer
Once a control request has been processed, the device returns a status to the host. This is a
zero length Data IN transaction.
1. The microcontroller waits for TXPKTRDY in the UDP_CSRx endpoint’s register to be
cleared. (At this step, TXPKTRDY must be cleared because the previous transaction
was a setup transaction or a Data OUT transaction.)
2. Without writing anything to the UDP_FDRx endpoint’s register, the microcontroller sets
TXPKTRDY. The USB device generates a Data IN packet using DATA1 PID.
3. This packet is acknowledged by the host and TXPKTRDY is set in the UDP_CSRx endpoint’s register.
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Figure 34-12. Data Out Followed by Status IN Transfer.
Device Sends a Status IN
to the Host
Host Sends the Last
Data Payload to the Device
USB Bus
Packets
Data OUT
PID
Data OUT
NAK
PID
Data IN
PID
ACK
PID
Interrupt Pending
RX_DATA_BKO
(USB_CSRx)
Cleared by Firmware
Set by USB Device
Cleared by USB Device
TXPKTRDY
(USB_CSRx)
Set by Firmware
34.5.2.6
Status OUT Transfer
Once a control request has been processed and the requested data returned, the host acknowledges by sending a zero length packet. This is a zero length Data OUT transaction.
1. The USB device receives a zero length packet. It sets RX_DATA_BK0 flag in the
UDP_CSRx register and acknowledges the zero length packet.
2. The microcontroller is notified that the USB device has received a zero length packet
sent by the host polling RX_DATA_BK0 in the UDP_CSRx register. An interrupt is pending while RX_DATA_BK0 is set. The number of bytes received in the endpoint’s
UDP_BCR register is equal to zero.
3. The microcontroller must clear RX_DATA_BK0.
Figure 34-13. Data IN Followed by Status OUT Transfer
Device Sends the Last
Data Payload to Host
USB Bus
Packets
Data IN
PID
Data IN
Device Sends a
Status OUT to Host
ACK
PID
Data OUT
PID
ACK
PID
Interrupt Pending
Set by USB Device
RX_DATA_BKO
(USB_CSRx)
Cleared by Firmware
TXCOMP
(USB_CSRx)
Set by USB Device
34.5.2.7
Cleared by Firmware
Stall Handshake
A stall handshake can be used in one of two distinct occasions. (For more information on the
stall handshake, refer to Chapter 8 of the Universal Serial Bus Specification, Rev 1.1.)
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• A functional stall is used when the halt feature associated with the endpoint is set. (Refer to
Chapter 9 of the Universal Serial Bus Specification, Rev 1.1, for more information on the halt
feature.)
• To abort the current request, a protocol stall is used, but uniquely with control transfer.
The following procedure generates a stall packet:
1. The microcontroller sets the FORCESTALL flag in the UDP_CSRx endpoint’s register.
2. The host receives the stall packet.
3. The microcontroller is notified that the device has sent the stall by polling the
STALLSENT to be set. An endpoint interrupt is pending while STALLSENT is set. The
microcontroller must clear STALLSENT to clear the interrupt.
When a setup transaction is received after a stall handshake, STALLSENT must be cleared in
order to prevent interrupts due to STALLSENT being set.
Figure 34-14. Stall Handshake (Data IN Transfer)
USB Bus
Packets
Data IN PID
Stall PID
Cleared by Firmware
FORCESTALL
Set by Firmware
Interrupt Pending
Cleared by Firmware
STALLSENT
Set by
USB Device
Figure 34-15. Stall Handshake (Data OUT Transfer)
USB Bus
Packets
Data OUT PID
Data OUT
Stall PID
Set by Firmware
FORCESTALL
Interrupt Pending
STALLSENT
Cleared by Firmware
Set by USB Device
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34.5.3
Controlling Device States
A USB device has several possible states. Please refer to Chapter 9 of the Universal Serial Bus
Specification, Rev 1.1.
Figure 34-16. USB Device State Diagram
Attached
Hub Reset
or
Deconfigured
Hub
Configured
Bus Inactive
Powered
Suspended
Bus Activity
Power
Interruption
Reset
Bus Inactive
Suspended
Default
Bus Activity
Reset
Address
Assigned
Bus Inactive
Address
Suspended
Bus Activity
Device
Deconfigured
Device
Configured
Bus Inactive
Configured
Suspended
Bus Activity
Movement from one state to another depends on the USB bus state or on standard requests
sent through control transactions via the default endpoint (endpoint 0).
After a period of bus inactivity, the UDP device enters Suspend Mode. Accepting Suspend/Resume requests from the USB host is mandatory. Constraints in Suspend Mode are very
strict for bus-powered applications; devices may not consume more than 500 uA on the USB
bus.
While in Suspend Mode, the host may wake up a device by sending a resume signal (bus activity) or a USB device may send a wake-up request to the host, e.g., waking up a PC by moving a
USB mouse.
The wake-up feature is not mandatory for all devices and must be negotiated with the host.
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34.5.3.1
From Powered State to Default State
After its connection to a USB host, the USB device waits for an end-of-bus reset. The USB host
stops driving a reset state once it has detected the device’s pull-up on DP. The unmasked flag
ENDBUSRES is set in the register UDP_ISR and an interrupt is triggered. The UDP software
enables the default endpoint, setting the EPEDS flag in the UDP_CSR[0] register and, optionally, enabling the interrupt for endpoint 0 by writing 1 to the UDP_IER register. The enumeration
then begins by a control transfer.
34.5.3.2
From Default State to Address State
After a set address standard device request, the USB host peripheral enters the address state.
Before this, it achieves the Status IN transaction of the control transfer, i.e., the UDP device sets
its new address once the TXCOMP flag in the UDP_CSR[0] register has been received and
cleared.
To move to address state, the driver software sets the FADDEN flag in the UDP_GLB_STATE,
sets its new address, and sets the FEN bit in the UDP_FADDR register.
34.5.3.3
From Address State to Configured State
Once a valid Set Configuration standard request has been received and acknowledged, the
device enables endpoints corresponding to the current configuration. This is done by setting the
EPEDS and EPTYPE fields in the UDP_CSRx registers and, optionally, enabling corresponding
interrupts in the UDP_IER register.
34.5.3.4
Enabling Suspend
When a Suspend (no bus activity on the USB bus) is detected, the RXSUSP signal in the
UDP_ISR register is set. This triggers an interrupt if the corresponding bit is set in the UDP_IMR
register.
This flag is cleared by writing to the UDP_ICR register. Then the device enters Suspend Mode.
As an example, the microcontroller switches to slow clock, disables the PLL and main oscillator,
and goes into Idle Mode. It may also switch off other devices on the board.
The USB device peripheral clocks may be switched off. However, the transceiver and the USB
peripheral must not be switched off, otherwise the resume is not detected.
34.5.3.5
Receiving a Host Resume
In suspend mode, the USB transceiver and the USB peripheral must be powered to detect the
RESUME. However, the USB device peripheral may not be clocked as the WAKEUP signal is
asynchronous.
Once the resume is detected on the bus, the signal WAKEUP in the UDP_ISR is set. It may generate an interrupt if the corresponding bit in the UDP_IMR register is set. This interrupt may be
used to wake-up the core, enable PLL and main oscillators and configure clocks. The WAKEUP
bit must be cleared as soon as possible by setting WAKEUP in the UDP_ICR register.
34.5.3.6
570
Sending an External Resume
The External Resume is negotiated with the host and enabled by setting the ESR bit in the
UDP_GLB_STATE. An asynchronous event on the ext_resume_pin of the peripheral generates
a WAKEUP interrupt. On early versions of the USP peripheral, the K-state on the USB line is
generated immediately. This means that the USB device must be able to answer to the host very
quickly. On recent versions, the software sets the RMWUPE bit in the UDP_GLB_STATE register once it is ready to communicate with the host. The K-state on the bus is then generated.
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
The WAKEUP bit must be cleared as soon as possible by setting WAKEUP in the UDP_ICR
register.
571
1768I–ATARM–09-Jul-09
34.6
USB Device Port (UDP) User Interface
Table 34-3.
USB Device Port Memory Map
Offset
Register
Name
Access
Reset State
0x000
Frame Number Register
UDP_FRM_NUM
Read
0x0000_0000
0x004
Global State Register
UDP_GLB_STAT
Read/Write
0x0000_0010
0x008
Function Address Register
UDP_FADDR
Read/Write
0x0000_0100
0x00C
Reserved
–
–
–
0x010
Interrupt Enable Register
UDP_IER
Write
0x014
Interrupt Disable Register
UDP_IDR
Write
0x018
Interrupt Mask Register
UDP_IMR
Read
0x0000_1200
0x01C
Interrupt Status Register
UDP_ISR
Read
0x0000_0000
0x020
Interrupt Clear Register
UDP_ICR
Write
0x024
Reserved
–
–
0x028
Reset Endpoint Register
UDP_RST_EP
Read/Write
0x02C
Reserved
–
–
–
0x030
Endpoint 0 Control and Status Register
UDP_CSR0
Read/Write
0x0000_0000
0x034
Endpoint 1 Control and Status Register
UDP_CSR1
Read/Write
0x0000_0000
0x038
Endpoint 2 Control and Status Register
UDP_CSR2
Read/Write
0x0000_0000
0x03C
Endpoint 3 Control and Status Register
UDP_CSR3
Read/Write
0x0000_0000
0x040
Endpoint 4 Control and Status Register
UDP_CSR4
Read/Write
0x0000_0000
0x044
Endpoint 5 Control and Status Register
UDP_CSR5
Read/Write
0x0000_0000
0x048
Reserved
–
–
–
0x04C
Reserved
–
–
–
0x050
Endpoint 0 FIFO Data Register
UDP_FDR0
Read/Write
0x0000_0000
0x054
Endpoint 1 FIFO Data Register
UDP_FDR1
Read/Write
0x0000_0000
0x058
Endpoint 2 FIFO Data Register
UDP_FDR2
Read/Write
0x0000_0000
0x05C
Endpoint 3 FIFO Data Register
UDP_FDR3
Read/Write
0x0000_0000
0x060
Endpoint 4 FIFO Data Register
UDP_FDR4
Read/Write
0x0000_0000
0x064
Endpoint 5 FIFO Data Register
UDP_FDR5
Read/Write
0x0000_0000
0x068
Reserved
–
–
–
0x06C
Reserved
–
–
–
0x074
Transceiver Control Register
UDP_TXVC
Read/Write
0x0000_0100
0x070
Reserved
–
–
–
572
–
AT91RM9200
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34.6.1
UDP Frame Number Register
Register Name:
UDP_FRM_NUM
Access Type:
Read-only
31
---
30
---
29
---
28
---
27
---
26
---
25
---
24
---
23
–
22
–
21
–
20
–
19
–
18
–
17
FRM_OK
16
FRM_ERR
15
–
14
–
13
–
12
–
11
–
10
9
FRM_NUM
8
7
6
5
4
3
2
1
0
FRM_NUM
• FRM_NUM[10:0]: Frame Number as Defined in the Packet Field Formats
This 11-bit value is incremented by the host on a per frame basis. This value is updated at each start of frame.
Value Updated at the SOF_EOP (Start of Frame End of Packet).
• FRM_ERR: Frame Error
This bit is set at SOF_EOP when the SOF packet is received containing an error.
This bit is reset upon receipt of SOF_PID.
• FRM_OK: Frame OK
This bit is set at SOF_EOP when the SOF packet is received without any error.
This bit is reset upon receipt of SOF_PID (Packet Identification).
In the Interrupt Status Register, the SOF interrupt is updated upon receiving SOF_PID. This bit is set without waiting for
EOP.
Note:
In the 8-bit Register Interface, FRM_OK is bit 4 of FRM_NUM_H and FRM_ERR is bit 3 of FRM_NUM_L.
573
1768I–ATARM–09-Jul-09
34.6.2
UDP Global State Register
Register Name:
UDP_GLB_STAT
Access Type:
Read/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
RMWUPE
3
RSMINPR
2
ESR
1
CONFG
0
FADDEN
This register is used to get and set the device state as specified in Chapter 9 of the USB Serial Bus Specification, Rev.1.1.
• FADDEN: Function Address Enable
Read:
0 = Device is not in address state.
1 = Device is in address state.
Write:
0 = No effect, only a reset can bring back a device to the default state.
1 = Set device in address state. This occurs after a successful Set Address request. Beforehand, the USB_FADDR register
must have been initialized with Set Address parameters. Set Address must complete the Status Stage before setting FADDEN. Please refer to chapter 9 of the Universal Serial Bus Specification, Rev. 1.1 to get more details.
• CONFG: Configured
Read:
0 = Device is not in configured state.
1 = Device is in configured state.
Write:
0 = Set device in a nonconfigured state
1 = Set device in configured state.
The device is set in configured state when it is in address state and receives a successful Set Configuration request.
Please refer to Chapter 9 of the Universal Serial Bus Specification, Rev. 1.1 to get more details.
• ESR: Enable Send Resume
0 = Disable the Remote Wake Up sequence.
1 = Remote Wake Up can be processed and the pin send_resume is enabled.
574
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• RSMINPR: A Resume Has Been Sent to the Host
Read:
0 = No effect.
1 = A Resume has been received from the host during Remote Wake Up feature.
• RMWUPE: Remote Wake Up Enable
0 = Must be cleared after receiving any HOST packet or SOF interrupt.
1 = Enables the K-state on the USB cable if ESR is enabled.
34.6.3
UDP Function Address Register
Register Name:
UDP_FADDR
Access Type:
Read/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
–
FEN
7
–
6
5
4
3
FADD
2
1
0
• FADD[6:0]: Function Address Value
The Function Address Value must be programmed by firmware once the device receives a set address request from the
host, and has achieved the status stage of the no-data control sequence. Please refer to the Universal Serial Bus Specification, Rev. 1.1 to get more information. After power up, or reset, the function address value is set to 0.
• FEN: Function Enable
Read:
0 = Function endpoint disabled.
1 = Function endpoint enabled.
Write:
0 = Disable function endpoint.
1 = Default value.
The Function Enable bit (FEN) allows the microcontroller to enable or disable the function endpoints. The microcontroller
sets this bit after receipt of a reset from the host. Once this bit is set, the USB device is able to accept and transfer data
packets from and to the host.
575
1768I–ATARM–09-Jul-09
34.6.4
UDP Interrupt Enable Register
Register Name:
UDP_IER
Access Type:
Write-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
–
14
–
13
WAKEUP
12
–
11
SOFINT
10
EXTRSM
9
8
RXRSM
RXSUSP
7
–
6
–
5
EP5INT
4
EP4INT
3
EP3INT
2
EP2INT
1
EP1INT
0
EP0INT
• EP0INT: Enable Endpoint 0 Interrupt
• EP1INT: Enable Endpoint 1 Interrupt
• EP2INT: Enable Endpoint 2Interrupt
• EP3INT: Enable Endpoint 3 Interrupt
• EP4INT: Enable Endpoint 4 Interrupt
• EP5INT: Enable Endpoint 5 Interrupt
0 = No effect.
1 = Enable corresponding Endpoint Interrupt.
• RXSUSP: Enable USB Suspend Interrupt
0 = No effect.
1 = Enable USB Suspend Interrupt.
• RXRSM: Enable USB Resume Interrupt
0 = No effect.
1 = Enable USB Resume Interrupt.
• EXTRSM: Enable External Resume Interrupt
0 = No effect.
1 = Enable External Resume Interrupt.
• SOFINT: Enable Start Of Frame Interrupt
0 = No effect.
1 = Enable Start Of Frame Interrupt.
• WAKEUP: Enable USB bus Wakeup Interrupt
576
AT91RM9200
1768I–ATARM–09-Jul-09
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0 = No effect.
1 = Enable USB bus Interrupt.
577
1768I–ATARM–09-Jul-09
34.6.5
UDP Interrupt Disable Register
Register Name:
UDP_IDR
Access Type:
Write-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
–
14
–
13
WAKEUP
12
–
11
SOFINT
10
EXTRSM
9
8
RXRSM
RXSUSP
7
–
6
–
5
EP5INT
4
EP4INT
3
EP3INT
2
EP2INT
1
EP1INT
0
EP0INT
• EP0INT: Disable Endpoint 0 Interrupt
• EP1INT: Disable Endpoint 1 Interrupt
• EP2INT: Disable Endpoint 2 Interrupt
• EP3INT: Disable Endpoint 3 Interrupt
• EP4INT: Disable Endpoint 4 Interrupt
• EP5INT: Disable Endpoint 5 Interrupt
0 = No effect.
1 = Disable corresponding Endpoint Interrupt.
• RXSUSP: Disable USB Suspend Interrupt
0 = No effect.
1 = Disable USB Suspend Interrupt.
• RXRSM: Disable USB Resume Interrupt
0 = No effect.
1 = Disable USB Resume Interrupt.
• EXTRSM: Disable External Resume Interrupt
0 = No effect.
1 = Disable External Resume Interrupt.
• SOFINT: Disable Start Of Frame Interrupt
0 = No effect.
1 = Disable Start Of Frame Interrupt
• WAKEUP: Disable USB Bus Interrupt
578
AT91RM9200
1768I–ATARM–09-Jul-09
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0 = No effect.
1 = Disable USB Bus Wakeup Interrupt.
579
1768I–ATARM–09-Jul-09
34.6.6
UDP Interrupt Mask Register
Register Name:
UDP_IMR
Access Type:
Read-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
–
14
–
13
WAKEUP
12
–
11
SOFINT
10
EXTRSM
9
8
RXRSM
RXSUSP
7
–
6
–
5
EP5INT
4
EP4INT
3
EP3INT
2
EP2INT
1
EP1INT
0
EP0INT
• EP0INT: Mask Endpoint 0 Interrupt
• EP1INT: Mask Endpoint 1 Interrupt
• EP2INT: Mask Endpoint 2 Interrupt
• EP3INT: Mask Endpoint 3 Interrupt
• EP4INT: Mask Endpoint 4 Interrupt
• EP5INT: Mask Endpoint 5 Interrupt
0 = Corresponding Endpoint Interrupt is disabled.
1 = Corresponding Endpoint Interrupt is enabled.
• RXSUSP: Mask USB Suspend Interrupt
0 = USB Suspend Interrupt is disabled.
1 = USB Suspend Interrupt is enabled.
• RXRSM: Mask USB Resume Interrupt.
0 = USB Resume Interrupt is disabled.
1 = USB Resume Interrupt is enabled.
• EXTRSM: Mask External Resume Interrupt
0 = External Resume Interrupt is disabled.
1 = External Resume Interrupt is enabled.
• SOFINT: Mask Start Of Frame Interrupt
0 = Start of Frame Interrupt is disabled.
1 = Start of Frame Interrupt is enabled.
• WAKEUP: USB Bus WAKEUP Interrupt
580
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
0 = USB Bus Wakeup Interrupt is disabled.
1 = USB Bus Wakeup Interrupt is enabled.
Note:
When the USB block is in suspend mode, the application may power down the USB logic. In this case, any USB HOST resume
request that is made must be taken into account and, thus, the reset value of the RXRSM bit of the register USB_IMR is
enabled.
581
1768I–ATARM–09-Jul-09
34.6.7
UDP Interrupt Status Register
Register Name:
UDP_ISR
Access Type:
Read -only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
14
13
11
10
9
8
–
–
WAKEUP
12
ENDBUSRE
S
SOFINT
EXTRSM
RXRSM
RXSUSP
7
–
6
–
5
EP5INT
3
EP3INT
2
EP2INT
1
EP1INT
0
EP0INT
4
EP4INT
• EP0INT: Endpoint 0 Interrupt Status
0 = No Endpoint0 Interrupt pending.
1 = Endpoint0 Interrupt has been raised.
Several signals can generate this interrupt. The reason can be found by reading UDP_CSR0:
RXSETUP set to 1
RX_DATA_BK0 set to 1
RX_DATA_BK1 set to 1
TXCOMP set to 1
STALLSENT set to 1
EP0INT is a sticky bit. Interrupt remains valid until EP0INT is cleared by writing in the corresponding UDP_CSR0 bit.
• EP1INT: Endpoint 1 Interrupt Status
0 = No Endpoint1 Interrupt pending.
1 = Endpoint1 Interrupt has been raised.
Several signals can generate this interrupt. The reason can be found by reading UDP_CSR1:
RXSETUP set to 1
RX_DATA_BK0 set to 1
RX_DATA_BK1 set to 1
TXCOMP set to 1
STALLSENT set to 1
EP1INT is a sticky bit. Interrupt remains valid until EP1INT is cleared by writing in the corresponding UDP_CSR1 bit.
582
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• EP2INT: Endpoint 2 Interrupt Status
0 = No Endpoint2 Interrupt pending.
1 = Endpoint2 Interrupt has been raised.
Several signals can generate this interrupt. The reason can be found by reading UDP_CSR2:
RXSETUP set to 1
RX_DATA_BK0 set to 1
RX_DATA_BK1 set to 1
TXCOMP set to 1
STALLSENT set to 1
EP2INT is a sticky bit. Interrupt remains valid until EP2INT is cleared by writing in the corresponding UDP_CSR2 bit.
• EP3INT: Endpoint 3 Interrupt Status
0 = No Endpoint3 Interrupt pending.
1 = Endpoint3 Interrupt has been raised.
Several signals can generate this interrupt. The reason can be found by reading UDP_CSR3:
RXSETUP set to 1
RX_DATA_BK0 set to 1
RX_DATA_BK1 set to 1
TXCOMP set to 1
STALLSENT set to 1
EP3INT is a sticky bit. Interrupt remains valid until EP3INT is cleared by writing in the corresponding UDP_CSR3 bit.
• EP4INT: Endpoint 4 Interrupt Status
0 = No Endpoint4 Interrupt pending.
1 = Endpoint4 Interrupt has been raised.
Several signals can generate this interrupt. The reason can be found by reading UDP_CSR4:
RXSETUP set to 1
RX_DATA_BK0 set to 1
RX_DATA_BK1 set to 1
TXCOMP set to 1
STALLSENT set to 1
EP4INT is a sticky bit. Interrupt remains valid until EP4INT is cleared by writing in the corresponding UDP_CSR4 bit.
• EP5INT: Endpoint 5 Interrupt Status
0 = No Endpoint5 Interrupt pending.
1 = Endpoint5 Interrupt has been raised.
583
1768I–ATARM–09-Jul-09
Several signals can generate this interrupt. The reason can be found by reading UDP_CSR5:
RXSETUP set to 1
RX_DATA_BK0 set to 1
RX_DATA_BK1 set to 1
TXCOMP set to 1
STALLSENT set to 1
EP5INT is a sticky bit. Interrupt remains valid until EP5INT is cleared by writing in the corresponding UDP_CSR5 bit.
• RXSUSP: USB Suspend Interrupt Status
0 = No USB Suspend Interrupt pending.
1 = USB Suspend Interrupt has been raised.
The USB device sets this bit when it detects no activity for 3ms. The USB device enters Suspend mode.
• RXRSM: USB Resume Interrupt Status
0 = No USB Resume Interrupt pending.
1 = USB Resume Interrupt has been raised.
The USB device sets this bit when a USB resume signal is detected at its port.
• EXTRSM: External Resume Interrupt Status
0 = No External Resume Interrupt pending.
1 = External Resume Interrupt has been raised.
This interrupt is raised when, in suspend mode, an asynchronous rising edge on the send_resume is detected.
If RMWUPE = 1, a resume state is sent in the USB bus.
• SOFINT: Start of Frame Interrupt Status
0 = No Start of Frame Interrupt pending.
1 = Start of Frame Interrupt has been raised.
This interrupt is raised each time a SOF token has been detected. It can be used as a synchronization signal by using
isochronous endpoints.
• ENDBUSRES: End of BUS Reset Interrupt Status
0 = No End of Bus Reset Interrupt pending.
1 = End of Bus Reset Interrupt has been raised.
This interrupt is raised at the end of a USB reset sequence. The USB device must prepare to receive requests on the endpoint 0. The host starts the enumeration, then performs the configuration.
• WAKEUP: USB Resume Interrupt Status
0 = No Wakeup Interrupt pending.
1 = A Wakeup Interrupt (USB Host Sent a RESUME or RESET) occurred since the last clear.
584
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1768I–ATARM–09-Jul-09
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34.6.8
UDP Interrupt Clear Register
Register Name:
UDP_ICR
585
1768I–ATARM–09-Jul-09
Access Type:
Write-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
14
13
11
10
9
8
–
–
WAKEUP
12
ENDBUSRE
S
SOFINT
EXTRSM
RXRSM
RXSUSP
7
–
6
–
5
–
3
–
2
–
1
–
0
–
4
–
• RXSUSP: Clear USB Suspend Interrupt
0 = No effect.
1 = Clear USB Suspend Interrupt.
• RXRSM: Clear USB Resume Interrupt
0 = No effect.
1 = Clear USB Resume Interrupt.
• EXTRSM: Clear External Resume Interrupt
0 = No effect.
1 = Clear External Resume Interrupt.
• SOFINT: Clear Start Of Frame Interrupt
0 = No effect.
1 = Clear Start Of Frame Interrupt.
• ENDBUSRES: Clear End of Bus Reset Interrupt
0 = No effect.
1 = Clear End of Bus Reset Interrupt.
• WAKEUP: Clear Wakeup Interrupt
0 = No effect.
1 = Clear Wakeup Interrupt.
586
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1768I–ATARM–09-Jul-09
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34.6.9
UDP Reset Endpoint Register
Register Name:
UDP_RST_EP
Access Type:
Read/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
EP5
4
EP4
3
EP3
2
EP2
1
EP1
0
EP0
• EP0: Reset Endpoint 0
• EP1: Reset Endpoint 1
• EP2: Reset Endpoint 2
• EP3: Reset Endpoint 3
• EP4: Reset Endpoint 4
• EP5: Reset Endpoint 5
This flag is used to reset the FIFO associated with the endpoint and the bit RXBYTECOUNT in the register UDP_CSRx.It
also resets the data toggle to DATA0. It is useful after removing a HALT condition on a BULK endpoint. Refer to Chapter
5.8.5 in the USB Serial Bus Specification, Rev.1.1.
Warning: This flag must be cleared at the end of the reset. It does not clear UDP_CSRx flags.
0 = No reset.
1 = Forces the corresponding endpoint FIF0 pointers to 0, therefore RXBYTECNT field is read at 0 in UDP_CSRx register.
587
1768I–ATARM–09-Jul-09
34.6.10 UDP Endpoint Control and Status Register
Register Name:
UDP_CSRx [x = 0. 7]
Access Type:
Read/Write
31
–
30
–
29
–
28
–
27
–
26
25
RXBYTECNT
24
23
22
21
20
19
18
17
16
RXBYTECNT
15
EPEDS
14
–
13
–
12
–
11
DTGLE
10
9
EPTYPE
8
7
6
RX_DATA_
BK1
5
FORCE
STALL
4
3
STALLSENT
ISOERROR
2
1
RX_DATA_
BK0
0
DIR
TXPKTRDY
RXSETUP
TXCOMP
WARNING: Due to a synchronization between MCK and UDPCK, the software application must wait for the end of the write
operation before executing another write by polling the bits which must be set/cleared.
//! Clear flags of UDP UDP_CSR register and waits for synchronization
#define Udp_ep_clr_flag(pInterface, endpoint, flags) { \
pInterface->UDP_CSR[endpoint] &= ~(flags); \
while ( (pInterface->UDP_CSR[endpoint] & (flags)) == (flags) ); \
}
//! Set flags of UDP UDP_CSR register and waits for synchronization
#define Udp_ep_set_flag(pInterface, endpoint, flags) { \
pInterface->UDP_CSR[endpoint] |= (flags); \
while ( (pInterface->UDP_CSR[endpoint] & (flags)) != (flags) ); \
}
• TXCOMP: Generates an IN packet with data previously written in the DPR
This flag generates an interrupt while it is set to one.
Write (Cleared by the firmware)
0 = Clear the flag, clear the interrupt.
1 = No effect.
Read (Set by the USB peripheral)
0 = Data IN transaction has not been acknowledged by the Host.
1 = Data IN transaction is achieved, acknowledged by the Host.
After having issued a Data IN transaction setting TXPKTRDY, the device firmware waits for TXCOMP to be sure that the
host has acknowledged the transaction.
588
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• RX_DATA_BK0: Receive Data Bank 0
This flag generates an interrupt while it is set to one.
Write (Cleared by the firmware)
0 = Notify USB peripheral device that data have been read in the FIFO's Bank 0.
1 = No effect.
Read (Set by the USB peripheral)
0 = No data packet has been received in the FIFO's Bank 0
1 = A data packet has been received, it has been stored in the FIFO's Bank 0.
When the device firmware has polled this bit or has been interrupted by this signal, it must transfer data from the FIFO to
the microcontroller memory. The number of bytes received is available in RXBYTCENT field. Bank 0 FIFO values are read
through the UDP_FDRx register. Once a transfer is done, the device firmware must release Bank 0 to the USB peripheral
device by clearing RX_DATA_BK0.
• RXSETUP: Sends STALL to the Host (Control endpoints)
This flag generates an interrupt while it is set to one.
Read
0 = No setup packet available.
1 = A setup data packet has been sent by the host and is available in the FIFO.
Write
0 = Device firmware notifies the USB peripheral device that it has read the setup data in the FIFO.
1 = No effect.
This flag is used to notify the USB device firmware that a valid Setup data packet has been sent by the host and successfully received by the USB device. The USB device firmware may transfer Setup data from the FIFO by reading the
UDP_FDRx register to the microcontroller memory. Once a transfer has been done, RXSETUP must be cleared by the
device firmware.
Ensuing Data OUT transactions is not accepted while RXSETUP is set.
• STALLSENT: Stall sent (Control, Bulk Interrupt endpoints)/ ISOERROR (Isochronous endpoints)
This flag generates an interrupt while it is set to one.
STALLSENT: this ends a STALL handshake
Read
0 = the host has not acknowledged a STALL.
1 = host has acknowledge the stall.
Write
0 = reset the STALLSENT flag, clear the interrupt.
1 = No effect.
This is mandatory for the device firmware to clear this flag. Otherwise the interrupt remains.
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Please refer to chapters 8.4.4 and 9.4.5 of the Universal Serial Bus Specification, Rev. 1.1 to get more information on the
STALL handshake.
ISOERROR: a CRC error has been detected in an isochronous transfer
Read
0 = No error in the previous isochronous transfer.
1 = CRC error has been detected, data available in the FIFO are corrupted.
Write
0 = reset the ISOERROR flag, clear the interrupt.
1 = No effect.
• TXPKTRDY: Transmit Packet Ready
This flag is cleared by the USB device.
This flag is set by the USB device firmware.
Read
0 = Data values can be written in the FIFO.
1 = Data values can not be written in the FIFO.
Write
0 = No effect.
1 = A new data payload is has been written in the FIFO by the firmware and is ready to be sent.
This flag is used to generate a Data IN transaction (device to host). Device firmware checks that it can write a data payload
in the FIFO, checking that TXPKTRDY is cleared. Transfer to the FIFO is done by writing in the UDP_FDRx register. Once
the data payload has been transferred to the FIFO, the firmware notifies the USB device setting TXPKTRDY to one. USB
bus transactions can start. TXCOMP is set once the data payload has been received by the host.
• FORCESTALL: Force Stall (used by Control, Bulk and Isochronous endpoints)
Write-only
0 = No effect.
1 = Send STALL to the host.
Please refer to chapters 8.4.4 and 9.4.5 of the Universal Serial Bus Specification, Rev. 1.1 to get more information on the
STALL handshake.
Control endpoints: during the data stage and status stage, this indicates that the microcontroller can not complete the
request.
Bulk and interrupt endpoints: notify the host that the endpoint is halted.
The host acknowledges the STALL, device firmware is notified by the STALLSENT flag.
• RX_DATA_BK1: Receive Data Bank 1 (only used by endpoints with ping-pong attributes)
This flag generates an interrupt while it is set to one.
Write (Cleared by the firmware)
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0 = Notify USB device that data have been read in the FIFO’s Bank 1.
1 = No effect.
Read (Set by the USB peripheral)
0 = No data packet has been received in the FIFO's Bank 1.
1 = A data packet has been received, it has been stored in FIFO's Bank 1.
When the device firmware has polled this bit or has been interrupted by this signal, it must transfer data from the FIFO to
microcontroller memory. The number of bytes received is available in RXBYTECNT field. Bank 1 FIFO values are read
through UDP_FDRx register. Once a transfer is done, the device firmware must release Bank 1 to the USB device by clearing RX_DATA_BK1.
• DIR: Transfer Direction (only available for control endpoints)
Read/Write
0 = Allow Data OUT transactions in the control data stage.
1 = Enable Data IN transactions in the control data stage.
Please refer to Chapter 8.5.2 of the Universal Serial Bus Specification, Rev. 1.1 to get more information on the control data
stage.
This bit must be set before UDP_CSRx/RXSETUP is cleared at the end of the setup stage. According to the request sent in
the setup data packet, the data stage is either a device to host (DIR = 1) or host to device (DIR = 0) data transfer. It is not
necessary to check this bit to reverse direction for the status stage.
• EPTYPE[2:0]: Endpoint Type
Read/Write
000
Control
001
Isochronous OUT
101
Isochronous IN
010
Bulk OUT
110
Bulk IN
011
Interrupt OUT
111
Interrupt IN
• DTGLE: Data Toggle
Read-only
0 = Identifies DATA0 packet.
1 = Identifies DATA1 packet.
Please refer to Chapter 8 of the Universal Serial Bus Specification, Rev. 1.1 to get more information on DATA0, DATA1
packet definitions.
• EPEDS: Endpoint Enable Disable
Read
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0 = Endpoint disabled.
1 = Endpoint enabled.
Write
0 = Disable endpoint.
1 = Enable endpoint.
• RXBYTECNT[10:0]: Number of Bytes Available in the FIFO
Read-only.
When the host sends a data packet to the device, the USB device stores the data in the FIFO and notifies the microcontroller. The microcontroller can load the data from the FIFO by reading RXBYTECENT bytes in the UDP_FDRx register.
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34.6.11 UDP FIFO Data Register
Register Name:
UDP_FDRx [x = 0. 7]
Access Type:
Read/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
FIFO_DATA
• FIFO_DATA[7:0]: FIFO Data Value
The microcontroller can push or pop values in the FIFO through this register.
RXBYTECNT in the corresponding UDP_CSRx register is the number of bytes to be read from the FIFO (sent by the host).
The maximum number of bytes to write is fixed by the Max Packet Size in the Standard Endpoint Descriptor. It can not be
more than the physical memory size associated to the endpoint. Please refer to the Universal Serial Bus Specification, Rev.
1.1 to get more information.
34.6.12 UDP Transceiver Control Register
Register Name:
UDP_TXVC
Access Type:
Read/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
–
TXVDIS
7
–
6
–
5
–
4
–
3
–
2
–
1
0
–
–
• TXVDIS: Transceiver Disable
When UDP is disabled, power consumption can be reduced significantly by disabling the embedded transceiver. This can
be done by setting TXVDIS field.
To enable the transceiver, TXVDIS must be cleared.
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35. USB Host Port (UHP)
35.1
Overview
The USB Host Port interfaces the USB with the host application. It handles Open HCI protocol
(Open Host Controller Interface) as well as USB v2.0 Full-speed and Low-speed protocols. It
also provides a simple Read/Write protocol on the ASB.
The USB Host Port integrates a root hub and transceivers on downstream ports. It provides several high-speed half-duplex serial communication ports at a baud rate of 12 Mbit/s. Up to 127
USB devices (printer, camera, mouse, keyboard, disk, etc.) and the USB hub can be connected
to the USB host in the USB “tiered star” topology.
The USB Host Port controller is fully compliant with the Open HCI specification. The standard
OHCI USB stack driver can be easily ported to ATMEL’s architecture in the same way all existing class drivers run without hardware specialization.
This means that all standard class devices are automatically detected and available to the user
application. As an example, integrating an HID (Human Interface Device) class driver provides a
plug & play feature for all USB keyboards and mouses.
Key features of the USB Host Port are:
• Compliance with Open HCI Rev 1.0 Specification
• Compliance with USB V2.0 Full Speed and Low Speed Specification
• Supports Both Low-speed 1.5 Mbps and Full-speed 12 Mbps USB devices
• Root Hub Integrated with Two Downstream USB Ports
• Embedded USB Transceivers (Number of Transceivers is Product Dependant)
• Supports Power Management
• Operates as a Master on the ASB Bus
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35.2
Block Diagram
Figure 35-1. USB Host Port Block Diagram
ASB
HCI
Slave Block
OHCI
Registers
HCI
Master Block
OHCI Root
Hub Registers
List Processor
Block
Control
ED & TD
Regsisters
Root Hub
and
Host SIE
Embedded USB
v2.0 Full-speed Transceiver
PORT S/M
USB transceiver
DP
DM
PORT S/M
USB transceiver
DP
DM
Data FIFO 64 x 8
uhp_int
MCK
UDPCK
Access to the USB host operational registers is achieved through the ASB bus interface. The
Open HCI host controller initializes master DMA transfers with the ASB bus as follows:
• Fetches endpoint descriptors and transfer descriptors
• Access to endpoint data from system memory
• Access to the HC communication area
• Write status and retire transfer Descriptor
Memory access errors (abort, misalignment) lead to an “UnrecoverableError” indicated by the
corresponding flag in the host controller operational registers.
All of the ASB memory map is accessible to the USB host master DMA. Thus there is no need to
define a dedicated physical memory area to the USB host.
The USB root hub is integrated in the USB host. Several USB downstream ports are available.
The number of downstream ports can be determined by the software driver reading the root
hub’s operational registers. Device connection is automatically detected by the USB host port
logic.
Warning: a pull-down must be connected to DP on the board. Otherwise The USB host will permanently detect a device connection on this port.
USB physical transceivers are integrated in the product and driven by the root hub’s ports.
Over current protection on ports can be activated by the USB host controller. Atmel’s standard
product does not dedicate pads to external over current protection.
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35.3
35.3.1
Product Dependencies
I/O Lines
DPs and DMs are not controlled by any PIO controllers. The embedded USB physical transceivers are controlled by the USB host controller.
35.3.2
Power Management
The USB host controller requires a 48 MHz clock. This clock must be generated by a PLL with a
correct accuracy of ± 0.25%.
Thus the USB device peripheral receives two clocks from the Power Management Controller
(PMC): the master clock MCK used to drive the peripheral user interface (MCK domain) and the
UHPCLK 48 MHz clock used to interface with the bus USB signals (Recovered 12 MHz domain).
35.3.3
Interrupt
The USB host interface has an interrupt line connected to the Advanced Interrupt Controller
(AIC).
Handling USB host interrupts requires programming the AIC before configuring the UHP.
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35.4
Functional Description
Please refer to the Open Host Controller Interface Specification for USB Release 1.0.a.
35.4.1
Host Controller Interface
There are two communication channels between the Host Controller and the Host Controller
Driver. The first channel uses a set of operational registers located on the USB Host Controller.
The Host Controller is the target for all communications on this channel. The operational registers contain control, status and list pointer registers. They are mapped in the ASB memory
mapped area. Within the operational register set there is a pointer to a location in the processor
address space named the Host Controller Communication Area (HCCA). The HCCA is the second communication channel. The host controller is the master for all communication on this
channel. The HCCA contains the head pointers to the interrupt Endpoint Descriptor lists, the
head pointer to the done queue and status information associated with start-of-frame
processing.
The basic building blocks for communication across the interface are Endpoint Descriptors (ED,
4 double words) and Transfer Descriptors (TD, 4 or 8 double words). The host controller assigns
an Endpoint Descriptor to each endpoint in the system. A queue of Transfer Descriptors is linked
to the Endpoint Descriptor for the specific endpoint.
Figure 35-2. USB Host Communication Channels
Device Enumeration
Open HCI
Operational
Registers
Host Controller
Communications Area
Mode
Interrupt 0
HCCA
Interrupt 1
Status
Interrupt 2
...
Event
Interrupt 31
Frame Int
...
Ratio
Control
Bulk
...
Done
Device Register
in Memory Space
= Transfer Descriptor
598
Shared RAM
= Endpoint Descriptor
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35.4.2
Host Controller Driver
Figure 35-3. USB Host Drivers
User Application
User Space
Kernel Drivers
Mini Driver
Class Driver
Class Driver
HUB Driver
USBD Driver
Host Controller Driver
Hardware
Host Controller Hardware
USB Handling is done through several layers as follows:
• Host controller hardware and serial engine: Transmit and receive USB data on the bus.
• Host controller driver: Drives the Host controller hardware and handle the USB protocol
• USB Bus driver and hub driver: Handles USB commands and enumeration. Offers a
hardware independent interface.
• Mini driver: Handles device specific commands.
Class driver: handles standard devices. This acts as a generic driver for a class of devices, for
example the HID driver.
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35.5
Typical Connection
Figure 35-4. Board Schematic to Interface UHP Device Controller
5V
0.20A
Type A Connector
10μF
HDMA
or
HDMB
HDPA
or
HDPB
100nF
10nF
27Ω
27Ω
47pF
15kΩ
15kΩ
47pF
As device connection is automatically detected by the USB host port logic, a pull-down must be
connected on DP and DM on the board. Otherwise the USB host will permanently detect a
device connection on this port.
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36. Ethernet MAC (EMAC)
36.1
Overview
The Ethernet MAC is the hardware implementation of the MAC sub-layer OSI reference model
between the physical layer (PHY) and the logical link layer (LLC). It controls the data exchange
between a host and a PHY layer according to Ethernet IEEE 802.3u data frame format. The
Ethernet MAC contains the required logic and transmit and receive FIFOs for DMA management. In addition, it is interfaced through MDIO/MDC pins for PHY layer management.
The Ethernet MAC can transfer data in media-independent interface (MII) or reduced mediaindependent interface (RMII) modes depending on the pinout configuration.
The aim of the reduced interface is to lower the pin count for a switch product that can be connected to multiple PHY interfaces. The characteristics specific to RMII mode are:
• Single clock at 50 MHz frequency
• Reduction of required control pins
• Reduction of data paths to di-bit (2-bit wide) by doubling clock frequency
• 10 Mbits/sec. and 100 Mbits/sec. data capability
The major features of the EMAC are:
• Compatibility with IEEE Standard 802.3
• 10 and 100 Mbits per second data throughput capability
• Full- and half-duplex operation
• MII or RMII interface to the physical layer
• Register interface to address, status and control registers
• DMA interface
• Interrupt generation to signal receive and transmit completion
• 28-byte transmit and 28-byte receive FIFOs
• Automatic pad and CRC generation on transmitted frames
• Address checking logic to recognize four 48-bit addresses
• Supports promiscuous mode where all valid frames are copied to memory
• Supports physical layer management through MDIO interface control of alarm and update
time/calendar data in
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36.2
Block Diagram
Figure 36-1. Block Diagram
ASB
ETXCK-ERXCK-EREFCK
DMA
EXTEN-EXTER
APB Bridge
ECRS-ECOL
ERXER-ERXDV
APB
Ethernet MAC
PIO
ERX0-ERX3
ETX0-ETX3
EMDC
PMC
MCK
EMDIO
Interrupt Control
EF100
EMAC IRQ
36.3
Application Block Diagram
Figure 36-2. Ethernet MAC Application Block Diagram
MIB Functions
WEB Pages
SNMP AGENT
WEB Server
TELNET Server
FTP Server
SNMP
HTTP
TELNET
FTP
TELNET Console
TCP/IP Socket API
UDP
TCP
IP
ARP/RARP
ETHERNET Driver
EMAC (802.3 compliant)
Physical Medium Independant Layer (MII or RMII)
Physical Medium Dependant Layer (10 Base-T Phy)
Link Connector (RJ45)
NETWORK
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36.4
36.4.1
Product Dependencies
I/O Lines
The pins used for interfacing the compliant external devices may be multiplexed with PIO lines.
The programmer must first program the PIO controllers to assign the EMAC pins to their peripheral functions. In RMII mode, unused pins (see Table 36-1: MII/RMII Signal Mapping) can be
used as general I/O lines.
36.4.2
Power Management
The EMAC may be clocked through the Power Management Controller (PMC), so the programmer must first configure the PMC to enable the EMAC clock.
If not used, about 400 µA current consumption can be saved by switching the EMAC in Local
Loopback Mode with the following sequence:
• EMAC clock is enabled
– write 0x1000000 in PMC_PCER
• EMAC Local Loopback is enabled
– set bit 1 in EMAC_CTL
• EMAC clock is disabled
– write 0x1000000 in PMC_PCDR
36.4.3
Interrupt
The EMAC has an interrupt line connected to the Advanced Interrupt Controller (AIC). Handling
the EMAC interrupt requires programming the AIC before configuring the EMAC.
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36.5
Functional Description
The Ethernet Media Access Control (EMAC) engine is fully compatible with the IEEE 802.3
Ethernet standard. It manages frame transmission and reception including collision detection,
preamble generation and detection, CRC control and generation and transmitted frame padding.
The MAC functions are:
• Frame encapsulation and decapsulation
• Error detection
• Media access management (MII, RMII)
Figure 36-3. EMAC Functional Block Diagram
EMAC
Address Checker
APB
Register Interface
Statistics Registers
ASB
604
DMA Interface
Control Registers
MDIO
Ethernet Receive
RMII/MII
Ethernet Transmit
MII/RMII
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36.5.1
36.5.1.1
Media Independent Interface
General
The Ethernet MAC is capable of interfacing to both RMII and MII Interfaces. The RMII bit in the
ETH_CFG register controls the interface that is selected. When this bit is set, the RMII interface
is selected, else the MII interface is selected.
The MII and RMII interface are capable of both 10Mb/s and 100Mb/s data rates as described in
the IEEE 802.3u standard. The signals used by the MII and RMII interfaces are described in the
Table 36-1.
Table 36-1.
Pin Configurations
Pin Name
MII
RMII
ETXCK_REFCK
ETXCK: Transmit Clock
REFCK: Reference Clock
ECRS_ECRSDV
ECRS: Carrier Sense
ECRSDV: Carrier Sense/Data Valid
ECOL
ECOL: Collision Detect
ERXDV
ERXDV: Data Valid
ERX0 - ERX3
ERX0 - ERX3: 4-bit Receive Data
ERX0 - ERX1: 2-bit Receive Data
ERXER
ERXER: Receive Error
ERXER: Receive Error
ERXCK
ERXCK: Receive Clock
ETXEN
ETXEN: Transmit Enable
ETXEN: Transmit Enable
ETX0-ETX3
ETX0 - ETX3: 4-bit Transmit Data
ETX0 - ETX1: 2-bit Transmit Data
ETXER
ETXER: Transmit Error
The intent of the RMII is to provide a reduced pin count alternative to the IEEE 802.3u MII. It
uses 2 bits for transmit (ETX0 and ETX1) and two bits for receive (ERX0 and ERX1). There is a
Transmit Enable (ETXEN), a Receive Error (ERXER), a Carrier Sense (ECRS_DV), and a 50
MHz Reference Clock (ETXCK_REFCK) for 100Mb/s data rate.
36.5.1.2
36.5.2
RMII Transmit and Receive Operation
The same signals are used internally for both the RMII and the MII operations. The RMII maps
these signals in a more pin-efficient manner. The transmit and receive bits are converted from a
4-bit parallel format to a 2-bit parallel scheme that is clocked at twice the rate. The carrier sense
and data valid signals are combined into the ECRS_ECRSDV signal. This signal contains information on carrier sense, FIFO status, and validity of the data. Transmit error bit (ETXER) and
collision detect (ECOL) are not used in RMII mode.
Transmit/Receive Operation
A standard IEEE 802.3 packet consists of the following fields: preamble, start of frame delimiter
(SFD), destination address (DA), source address (SA), length, data (Logical Link Control Data)
and frame check sequence CRC32 (FCS).
Table 36-2.
Packet Format
Frame(1)
Preamble
Alternating 1s/0s
Up to 7 bytes
SFD
DA
SA
Length/type
1 byte
6 bytes
6 bytes
2 bytes
LLC Data
PAD
FCS
4 bytes
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Note:
Frame Length between 64 bytes and 1518 bytes.
The packets are Manchester-encoded and -decoded and transferred serially using NRZ data
with a clock. All fields are of fixed length except for the data field. The MAC generates and
appends the preamble, SFD and CRC fields during transmission.
The preamble and SFD fields are stripped during reception.
36.5.2.1
Preamble and Start of Frame Delimiter (SFD)
The preamble field is used to acquire bit synchronization with an incoming packet. When transmitted, each packet contains 62 bits of alternating 1,0 preamble. Some of this preamble is lost
as the packet travels through the network. Byte alignment is performed with the Start of Frame
Delimiter (SFD) pattern that consists of two consecutive 1's.
36.5.2.2
Destination Address
The destination address (DA) indicates the destination of the packet on the network and is used
to filter unwanted packets. There are three types of address formats: physical, multicast and
broadcast. The physical address is a unique address that corresponds only to a single node. All
physical addresses have an MSB of 0.
Multicast addresses begin with an MSB of 1. The MAC filters multicast addresses using a standard hashing algorithm that maps all multicast addresses into a 6-bit value. This 6-bit value
indexes a 64-bit array that filters the value. If the address consists of all ones, it is a broadcast
address, indicating that the packet is intended for all nodes.
36.5.2.3
Source Address
The source address (SA) is the physical address of the node that sent the packet. Source
addresses cannot be multicast or broadcast addresses. This field is passed to buffer memory.
36.5.2.4
Length/Type
If the value of this field is less than or equal to 1500, then the Length/Type field indicates the
number of bytes in the subsequent LLC Data field. If the value of this field is greater than or
equal to 1536, then the Length/Type field indicates the nature of the MAC client protocol (protocol type).
36.5.2.5
LLC Data
The data field consists of anywhere from 46 to 1500 bytes. Messages longer than 1500 bytes
need to be broken into multiple packets. Messages shorter than 46 bytes require appending a
pad to bring the data field to the minimum length of 46 bytes. If the data field is padded, the number of valid data bytes is indicated in the length field.
36.5.2.6
FCS Field
The Frame Check Sequence (FCS) is a 32-bit CRC field, calculated and appended to a packet
during transmission to allow detection of errors when a packet is received. During reception,
error free packets result in a specific pattern in the CRC generator. Packets with improper CRC
will be rejected.
36.5.3
606
Frame Format Extensions
The original Ethernet standards defined the minimum frame size as 64 bytes and the maximum
as 1518 bytes. These numbers include all bytes from the Destination MAC Address field through
the Frame Check Sequence field. The Preamble and Start Frame Delimiter fields are not
included when quoting the size of a frame. The IEEE 802.3ac standard extended the maximum
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allowable frame size to 1522 bytes to allow a VLAN tag to be inserted into the Ethernet frame
format. The bit BIG defined in the ETH_CFG register aims to process packet with VLAN tag.
The VLAN protocol permits insertion of an identifier, or tag, into the Ethernet frame format to
identify the VLAN to which the frame belongs. It allows frames from stations to be assigned to
logical groups. This provides various benefits, such as easing network administration, allowing
formation of work groups, enhancing network security, and providing a means of limiting broadcast domains (refer to IEEE standard 802.1Q for definition of the VLAN protocol). The 802.3ac
standard defines only the implementation details of the VLAN protocol that are specific to
Ethernet.
If present, the 4-byte VLAN tag is inserted into the Ethernet frame between the Source MAC
Address field and the Length field. The first 2-bytes of the VLAN tag consist of the “802.1Q Tag
Type” and are always set to a value of 0x8100. The 0x8100 value is a reserved Length/Type
field assignment that indicates the presence of the VLAN tag, and signals that the traditional
Length/Type field can be found at an offset of four bytes further into the frame. The last two
bytes of the VLAN tag contain the following information:
• The first three bits are a User Priority Field that may be used to assign a priority level to the
Ethernet frame.
• The following one bit is a Canonical Format Indicator (CFI) used in Ethernet frames to
indicate the presence of a Routing Information Field (RIF).
• The last twelve bits are the VLAN Identifier (VID) that uniquely identifies the VLAN to which
the Ethernet frame belongs.
With the addition of VLAN tagging, the 802.3ac standard permits the maximum length of an
Ethernet frame to be extended from 1518 bytes to 1522 bytes. Table 36-3 illustrates the format
of an Ethernet frame that has been “tagged” with a VLAN identifier according to the IEEE
802.3ac standard.
Table 36-3.
Ethernet Frame with VLAN Tagging
Preamble
7 bytes
Start Frame Delimiter
1 byte
Dest. MAC Address
6 bytes
Source MAC Address
6 bytes
Length/Type = 802.1Q Tag Type
Tag Control Information
2 bytes
Length / Type
2 bytes
MAC Client Data
0 - n bytes
Pad
0 - p bytes
Frame Check Sequence
36.5.4
2 byte
4 bytes
DMA Operations
Frame data is transferred to and from the Ethernet MAC via the DMA interface. All transfers are
32-bit words and may be single accesses or bursts of two, three or four words. Burst accesses
do not cross 16-byte boundaries.
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The DMA controller performs four types of operations on the ASB bus. In order of priority, these
operations are receive buffer manager read, receive buffer manager write, transmit data DMA
read and receive data DMA write.
36.5.4.1
Transmitter Mode
Transmit frame data needs to be stored in contiguous memory locations. It does not need to be
word-aligned.
The transmit address register is written with the address of the first byte to be transmitted.
Transmit is initiated by writing the number of bytes to transfer (length) to the transmit control
register.
The transmit channel then reads data from memory 32 bits at a time and places them in the
transmit FIFO.
The transmit block starts frame transmission when three words have been loaded into the FIFO.
The transmit address register must be written before the transmit control register. While a frame
is being transmitted, it is possible to set up one other frame for transmission by writing new values to the transmit address and control registers. Reading the transmit address register returns
the address of the buffer currently being accessed by the transmit FIFO.
Reading the transmit control register returns the total number of bytes to be transmitted. The
BNQ bit in the Transmit Status Register indicates whether another buffer can be safely queued.
An interrupt is generated whenever this bit is set.
Frame assembly starts by adding preamble and the start frame delimiter. Data is taken from the
transmit FIFO word-by-word. If necessary, padding is added to make the frame length 60 bytes.
The CRC is calculated as a 32-bit polynomial. This is inverted and appended to the end of the
frame, making the frame length a minimum of 64 bytes. The CRC is not appended if the NCRC
bit is set in the transmit control register.
In full-duplex mode, frames are transmitted immediately. Back-to-back frames are transmitted at
least 96 bit times apart to guarantee the inter-frame gap.
In half-duplex mode, the transmitter checks carrier sense. If asserted, it waits for it to de-assert
and then starts transmission after the inter-frame gap of 96 bit-times.
If the collision signal is asserted during transmission, the transmitter transmits a jam sequence
of 32 bits taken from the data register and then retries transmission after the backoff time has
elapsed. An error is indicated and any further attempts aborted if 16 attempts cause collisions.
If transmit DMA underruns, bad CRC is automatically appended using the same mechanism as
jam insertion. Underrun also causes TXER to be asserted.
36.5.4.2
Receiver Mode
When a packet is received, it is checked for valid preamble, CRC, alignment, length and
address. If all these criteria are met, the packet is stored successfully in a receive buffer. If at the
end of reception the CRC is bad, then the received buffer is recovered. Each received frame
including CRC is written to a single receive buffer.
Receive buffers are word-aligned and are capable of containing 1518 or 1522 bytes (BIG = 1 in
ETH_CFG) of data (the maximum length of an Ethernet frame).
The start location for each received frame is stored in memory in a list of receive buffer descriptors at a location pointed to by the receive buffer queue pointer register. Each entry in the list
608
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AT91RM9200
consists of two words. The first word is the address of the received buffer; the second is the
receive status. Table 36-4 defines an entry in the received buffer descriptor list.
To receive frames, the buffer queue must be initialized by writing an appropriate address to bits
[31:2] in the first word of each list entry. Bit zero of word zero must be written with zero.
After a frame is received, bit zero becomes set and the second word indicates what caused the
frame to be copied to memory. The start location of the received buffer descriptor list should be
written to the received buffer queue pointer register before receive is enabled (by setting the
receive enable bit in the network control register). As soon as the received block starts writing
received frame data to the receive FIFO, the received buffer manager reads the first receive buffer location pointed to by the received buffer queue pointer register. If the filter block is active,
the frame should be copied to memory; the receive data DMA operation starts writing data into
the receive buffer. If an error occurs, the buffer is recovered. If the frame is received without
error, the queue entry is updated. The buffer pointer is rewritten to memory with its low-order bit
set to indicate successful frame reception and a used buffer. The next word is written with the
length of the frame and how the destination address was recognized. The next receive buffer
location is then read from the following word or, if the current buffer pointer had its wrap bit set,
the beginning of the table. The maximum number of buffer pointers before a wrap bit is seen is
1024. If a wrap bit is not seen by then, a wrap bit is assumed in that entry. The received buffer
queue pointer register must be written with zero in its lower-order bit positions to enable the
wrap function to work correctly.
If bit zero is set when the receive buffer manager reads the location of the receive buffer, then
the buffer has already been used and cannot be used again until software has processed the
frame and cleared bit zero. In this case, the DMA block sets the buffer unavailable bit in the
received status register and triggers an interrupt. The frame is discarded and the queue entry is
reread on reception of the next frame to see if the buffer is now available. Each discarded frame
increments a statistics register that is cleared on being read. When there is network congestion,
it is possible for the MAC to be programmed to apply back pressure.
This is when half-duplex mode collisions are forced on all received frames by transmitting 64 bits
of data (a default pattern).
Reading the received buffer queue register returns the location of the queue entry currently
being accessed. The queue wraps around to the start after either 1024 entries (i.e., 2048 words)
or when the wrap bit is found to be set in bit 1 of the first word of an entry.
Table 36-4.
Bit
Received Buffer Descriptor List
Function
Word 0
31:2
Base address of receive buffer
1
Wrap bit. If this bit is set, the counter that is ORed with the received buffer queue
pointer register to give the pointer to entries in this table is cleared after the buffer is
used.
0
Ownership bit. 1 indicates software owns the pointer, 0 indicates that the DMA owns
the buffer. If this bit is not zero when the entry is read by the receiver, the buffer
unavailable bit is set in the received status register and the receiver goes inactive.
Word 1
31
Global all ones broadcast address detected
609
1768I–ATARM–09-Jul-09
Table 36-4.
36.5.5
Received Buffer Descriptor List
Bit
Function
30
Multicast hash match
29
Unicast hash match
28
External address (optional)
27
Unknown source address (reserved for future use)
26
Local address match (Specific address 1 match)
25
Local address match (Specific address 2 match)
24
Local address match (Specific address 3 match)
23
Local address match (Specific address 4 match)
22:11
Reserved; written to 0
10:0
Length of frame including FCS
Address Checking
Whether or not a frame is stored depends on what is enabled in the network configuration register, the contents of the specific address and hash registers and the frame destination address. In
this implementation of the MAC the frame source address is not checked.
A frame is not copied to memory if the MAC is transmitting in half-duplex mode at the time a destination address is received.
The hash register is 64 bits long and takes up two locations in the memory map.
There are four 48-bit specific address registers, each taking up two memory locations. The first
location contains the first four bytes of the address; the second location contains the last two
bytes of the address stored in its least significant byte positions. The addresses stored can be
specific, group, local or universal.
Ethernet frames are transmitted a byte at a time, LSB first. The first bit (i.e., the LSB of the first
byte) of the destination address is the group/individual bit and is set one for multicast addresses
and zero for unicast. This bit corresponds to bit 24 of the first word of the specific address register. The MSB of the first byte of the destination address corresponds to bit 31 of the specific
address register.
The specific address registers are compared to the destination address of received frames once
they have been activated. Addresses are deactivated at reset or when the first byte [47:40] is
written and activated or when the last byte [7:0] is written. If a receive frame address matches an
active address, the local match signal is set and the store frame pulse signal is sent to the DMA
block via the HCLK synchronization block.
A frame can also be copied if a unicast or multicast hash match occurs, it has the broadcast
address of all ones, or the copy all frames bit in the network configuration register is set.
The broadcast address of 0xFFFFFFFF is recognized if the no broadcast bit in the network configuration register is zero. This sets the broadcast match signal and triggers the store frame
signal.
The unicast hash enable and the multicast hash enable bits in the network configuration register
enable the reception of hash matched frames. So all multicast frames can be received by setting
all bits in the hash register.
610
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The CRC algorithm reduces the destination address to a 6-bit index into a 64-bit hash register.If
the equivalent bit in the register is set, the frame is matched depending on whether the frame is
multicast or unicast and the appropriate match signals are sent to the DMA block. If the copy all
frames bit is set in the network configuration register, the store frame pulse is always sent to the
DMA block as soon as any destination address is received.
611
1768I–ATARM–09-Jul-09
36.6
Ethernet MAC (EMAC) User Interface
Table 36-5.
EMAC Register Mapping
Offset
Register
Register Name
Read/Write
Reset
0x00
EMAC Control Register
ETH_CTL
Read/Write
0x0
0x04
EMAC Configuration Register
ETH_CFG
Read/Write
0x800
0x08
EMAC Status Register
ETH_SR
Read-only
0x6
0x0C
EMAC Transmit Address Register
ETH_TAR
Read/Write
0x0
0x10
EMAC Transmit Control Register
ETH_TCR
Read/Write
0x0
0x14
EMAC Transmit Status Register
ETH_TSR
Read/Write
0x18
0x18
EMAC Receive Buffer Queue Pointer
ETH_RBQP
Read/Write
0x0
0x1C
Reserved
–
Read-only
0x0
0x20
EMAC Receive Status Register
ETH_RSR
Read/Write
0x0
0x24
EMAC Interrupt Status Register
ETH_ISR
Read/Write
0x0
0x28
EMAC Interrupt Enable Register
ETH_IER
Write-only
–
0x2C
EMAC Interrupt Disable Register
ETH_IDR
Write-only
–
0x30
EMAC Interrupt Mask Register
ETH_IMR
Read-only
0xFFF
0x34
EMAC PHY Maintenance Register
ETH_MAN
Read/Write
0x0
Statistics Registers
612
(1)
0x40
Frames Transmitted OK Register
ETH_FRA
Read/Write
0x0
0x44
Single Collision Frame Register
ETH_SCOL
Read/Write
0x0
0x48
Multiple Collision Frame Register
ETH_MCOL
Read/Write
0x0
0x4C
Frames Received OK Register
ETH_OK
Read/Write
0x0
0x50
Frame Check Sequence Error Register
ETH_SEQE
Read/Write
0x0
0x54
Alignment Error Register
ETH_ALE
Read/Write
0x0
0x58
Deferred Transmission Frame Register
ETH_DTE
Read/Write
0x0
0x5C
Late Collision Register
ETH_LCOL
Read/Write
0x0
0x60
Excessive Collision Register
ETH_ECOL
Read/Write
0x0
0x64
Transmit Underrun Error Register
ETH_TUE
Read/Write
0x0
0x68
Carrier Sense Error Register
ETH_CSE
Read/Write
0x0
0x6C
Discard RX Frame Register
ETH_DRFC
Read/Write
0x0
0x70
Receive Overrun Register
ETH_ROV
Read/Write
0x0
0x74
Code Error Register
ETH_CDE
Read/Write
0x0
0x78
Excessive Length Error Register
ETH_ELR
Read/Write
0x0
0x7C
Receive Jabber Register
ETH_RJB
Read/Write
0x0
0x80
Undersize Frame Register
ETH_USF
Read/Write
0x0
0x84
SQE Test Error Register
ETH_SQEE
Read/Write
0x0
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table 36-5.
EMAC Register Mapping (Continued)
Offset
Register
Register Name
Read/Write
Reset
Address Registers
Note:
0x90
EMAC Hash Address Low [31:0]
ETH_HSL
Read/Write
0x0
0x94
EMAC Hash Address High [63:32]
ETH_HSH
Read/Write
0x0
0x98
EMAC Specific Address 1 Low, First 4
Bytes
ETH_SA1L
Read/Write
0x0
0x9C
EMAC Specific Address 1 High, Last 2
Bytes
ETH_SA1H
Read/Write
0x0
0xA0
EMAC Specific Address 2 Low, First 4
Bytes
ETH_SA2L
Read/Write
0x0
0xA4
EMAC Specific Address 2 High, Last 2
Bytes
ETH_SA2H
Read/Write
0x0
0xA8
EMAC Specific Address 3 Low, First 4
Bytes
ETH_SA3L
Read/Write
0x0
0xAC
EMAC Specific Address 3 High, Last 2
Bytes
ETH_SA3H
Read/Write
0x0
0xB0
EMAC Specific Address 4 Low, First 4
Bytes
ETH_SA4L
Read/Write
0x0
0xB4
EMAC Specific Address 4 High, Last 2
Bytes
ETH_SA4H
Read/Write
0x0
1. For further details on the statistics registers, see Table 36-6 on page 629.
613
1768I–ATARM–09-Jul-09
36.6.1
Name:
EMAC Control Register
ETH_CTL
Access Type:
Read/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
–
–
–
–
–
–
–
BP
7
6
5
4
3
2
1
0
WES
ISR
CSR
MPE
TE
RE
LBL
LB
• LB: Loopback
Optional. When set, loopback signal is at high level.
• LBL: Loopback Local
When set, connects ETX[3:0] to ERX[3:0], ETXEN to ERXDV, forces full duplex and drives ERXCK and ETXCK_REFCK
with MCK divided by 4.
• RE: Receive Enable
When set, enables the Ethernet MAC to receive data.
• TE: Transmit Enable
When set, enables the Ethernet transmitter to send data.
• MPE: Management Port Enable
Set to one to enable the management port. When zero, forces MDIO to high impedance state.
• CSR: Clear Statistics Registers
This bit is write-only. Writing a one clears the statistics registers.
• ISR: Increment Statistics Registers
This bit is write-only. Writing a one increments all the statistics registers by one for test purposes.
• WES: Write Enable for Statistics Registers
Setting this bit to one makes the statistics registers writable for functional test purposes.
• BP: Back Pressure
If this field is set, then in half-duplex mode collisions are forced on all received frames by transmitting 64 bits of data
(default pattern).
614
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1768I–ATARM–09-Jul-09
AT91RM9200
36.6.2
Name:
EMAC Configuration Register
ETH_CFG
Access Type:
Read/Write
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
–
–
RMII
RTY
10
CLK
9
8
EAE
BIG
7
6
5
4
3
2
1
0
UNI
MTI
NBC
CAF
–
BR
FD
SPD
• SPD: Speed
Set to 1 to indicate 100 Mbit/sec, 0 for 10 Mbit/sec. Has no other functional effect.
• FD: Full Duplex
If set to 1, the transmit block ignores the state of collision and carrier sense and allows receive while transmitting.
• BR: Bit Rate
Optional.
• CAF: Copy All Frames
When set to 1, all valid frames are received.
• NBC: No Broadcast
When set to 1, frames addressed to the broadcast address of all ones are not received.
• MTI: Multicast Hash Enable
When set multicast frames are received when six bits of the CRC of the destination address point to a bit that is set in the
hash register.
• UNI: Unicast Hash Enable
When set, unicast frames are received when six bits of the CRC of the destination address point to a bit that is set in the
hash register.
• BIG: Receive 1522 Bytes
When set, the MAC receives up to 1522 bytes. Normally the MAC receives frames up to 1518 bytes in length.
This bit allows to receive extended Ethernet frame with “VLAN tag” (IEEE 802.3ac)
• EAE: External Address Match Enable
Optional.
• CLK
615
1768I–ATARM–09-Jul-09
The system clock (MCK) is divided down to generate MDC (the clock for the MDIO). To conform with IEEE standard 802.3
MDC must not exceed 2.5 MHz. At reset this field is set to 10 so that MCK is divided by 32.
CLK
MDC
00
MCK divided by 8
01
MCK divided by 16
10
MCK divided by 32
11
MCK divided by 64
• RTY: Retry Test
When set, the time between frames is always one time slot. For test purposes only. Must be cleared for normal operation.
• RMII: Reduce MII
When set, this bit enables the RMII operation mode. When reset, it selects the MII mode.
616
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
36.6.3
Name:
EMAC Status Register
ETH_SR
Access Type:
Read only
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
–
–
–
–
–
IDLE
MDIO
LINK
• LINK
Reserved.
• MDIO
0 = MDIO pin not set.
1 = MDIO pin set.
• IDLE
0 = PHY logic is idle.
1 = PHY logic is running.
617
1768I–ATARM–09-Jul-09
36.6.4
Name:
EMAC Transmit Address Register
ETH_TAR
Access Type:
31
Read/Write
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
ADDRESS
23
22
21
20
ADDRESS
15
14
13
12
ADDRESS
7
6
5
4
ADDRESS
• ADDRESS: Transmit Address Register
Written with the address of the frame to be transmitted, read as the base address of the buffer being accessed by the transmit FIFO. Note that if the two least significant bits are not zero, transmit starts at the byte indicated.
36.6.5
Name:
EMAC Transmit Control Register
ETH_TCR
Access Type:
Read/Write
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
10
9
8
15
14
13
12
11
NCRC
–
–
–
–
7
6
5
4
3
LEN
2
1
0
LEN
• LEN: Transmit Frame Length
This register is written to the number of bytes to be transmitted excluding the four CRC bytes unless the no CRC bit is
asserted. Writing these bits to any non-zero value initiates a transmission. If the value is greater than 1514 (1518 if no CRC
is being generated), an oversize frame is transmitted. This field is buffered so that a new frame can be queued while the
previous frame is still being transmitted. Must always be written in address-then-length order. Reads as the total number of
bytes to be transmitted (i.e., this value does not change as the frame is transmitted.) Frame transmission does not start
until two 32-bit words have been loaded into the transmit FIFO. The length must be great enough to ensure two words are
loaded.
• NCRC: No CRC
If this bit is set, it is assumed that the CRC is included in the length being written in the low-order bits and the MAC does not
append CRC to the transmitted frame. If the buffer is not at least 64 bytes long, a short frame is sent. This field is buffered
so that a new frame can be queued while the previous frame is still being transmitted. Reads as the value of the frame currently being transmitted.
618
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
36.6.6
Name:
EMAC Transmit Status Register
ETH_TSR
Access Type:
Read/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
–
UND
COMP
BNQ
IDLE
RLE
COL
OVR
• OVR: Ethernet Transmit Buffer Overrun
Software has written to the Transmit Address Register (ETH_TAR) or Transmit Control Register (ETH_TCR) when bit BNQ
was not set. Cleared by writing a one to this bit.
• COL: Collision Occurred
Set by the assertion of collision. Cleared by writing a one to this bit.
• RLE: Retry Limit Exceeded
Cleared by writing a one to this bit.
• IDLE: Transmitter Idle
Asserted when the transmitter has no frame to transmit. Cleared when a length is written to transmit frame length portion of
the Transmit Control register. This bit is read-only.
• BNQ: Ethernet Transmit Buffer not Queued
Software may write a new buffer address and length to the transmit DMA controller when set. Cleared by having one frame
ready to transmit and another in the process of being transmitted. This bit is read-only.
• COMP: Transmit Complete
Set when a frame has been transmitted. Cleared by writing a one to this bit.
• UND: Transmit Underrun
Set when transmit DMA was not able to read data from memory in time. If this happens, the transmitter forces bad CRC.
Cleared by writing a one to this bit.
619
1768I–ATARM–09-Jul-09
36.6.7
Name:
EMAC Receive Buffer Queue Pointer Register
ETH_RBQP
Access Type:
31
Read/Write
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
ADDRESS
23
22
21
20
ADDRESS
15
14
13
12
ADDRESS
7
6
5
4
ADDRESS
• ADDRESS: Receive Buffer Queue Pointer
Written with the address of the start of the receive queue, reads as a pointer to the current buffer being used. The receive
buffer is forced to word alignment.
36.6.8
Name:
EMAC Receive Status Register
ETH_RSR
Access Type:
Read/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
–
–
–
–
–
OVR
REC
BNA
• BNA: Buffer Not Available
An attempt was made to get a new buffer and the pointer indicated that it was owned by the processor. The DMA rereads
the pointer each time a new frame starts until a valid pointer is found. This bit is set at each attempt that fails even if it has
not had a successful pointer read since it has been cleared. Cleared by writing a one to this bit.
• REC: Frame Received
One or more frames have been received and placed in memory. Cleared by writing a one to this bit.
• OVR: RX Overrun
The DMA block was unable to store the receive frame to memory, either because the ASB bus was not granted in time or
because a not OK HRESP was returned. The buffer is recovered if this happens. Cleared by writing a one to this bit.
620
AT91RM9200
1768I–ATARM–09-Jul-09
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36.6.9
Name:
EMAC Interrupt Status Register
ETH_ISR
Access Type:
Read/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
–
–
–
–
ABT
ROVR
LINK
TIDLE
7
6
5
4
3
2
1
0
TCOM
TBRE
RTRY
TUND
TOVR
RBNA
RCOM
DONE
• DONE: Management Done
The PHY maintenance register has completed its operation. Cleared on read.
• RCOM: Receive Complete
A frame has been stored in memory. Cleared on read.
• RBNA: Receive Buffer Not Available
Cleared on read.
• TOVR: Transmit Buffer Overrun
Software has written to the Transmit Address Register (ETH_TAR) or Transmit Control Register (ETH_TCR) when BNQ of
the Transmit Status Register (ETH_TSR) was not set. Cleared on read.
• TUND: Transmit Buffer Underrun
Ethernet transmit buffer underrun. The transmit DMA did not complete fetch frame data in time for it to be transmitted.
Cleared on read.
• RTRY: Retry Limit
Retry limit exceeded. Cleared on read.
• TBRE: Transmit Buffer Register Empty
Software may write a new buffer address and length to the transmit DMA controller. Cleared by having one frame ready to
transmit and another in the process of being transmitted. Cleared on read.
• TCOM: Transmit Complete
Set when a frame has been transmitted. Cleared on read.
• TIDLE: Transmit Idle
Set when all frames have been transmitted. Cleared on read.
• LINK
621
1768I–ATARM–09-Jul-09
Set when LINK pin changes value. Optional.
• ROVR: RX Overrun
Set when the RX overrun status bit is set. Cleared on read.
• ABT: Abort
Set when an abort occurs during a DMA transfer. Cleared on read.
622
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
36.6.10
Name:
EMAC Interrupt Enable Register
ETH_IER
Access Type:
Write only
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
–
ABT
ROVR
LINK
TIDLE
7
6
5
4
3
2
1
0
TCOM
TBRE
RTRY
TUND
TOVR
RBNA
RCOM
DONE
• DONE: Management Done Interrupt Enable
• RCOM: Receive Complete Interrupt Enable
• RBNA: Receive Buffer Not Available Interrupt Enable
• TOVR: Transmit Buffer Overrun Interrupt Enable
• TUND: Transmit Buffer Underrun Interrupt Enable
• RTRY: Retry Limit Interrupt Enable
• TBRE: Transmit Buffer Register Empty Interrupt Enable
• TCOM: Transmit Complete Interrupt Enable
• TIDLE: Transmit Idle Interrupt Enable
• LINK: LINK Interrupt Enable
• ROVR: RX Overrun Interrupt Enable
• ABT: Abort Interrupt Enable
0: No effect.
1: Enables the corresponding interrupt.
623
1768I–ATARM–09-Jul-09
36.6.11
Name:
EMAC Interrupt Disable Register
ETH_IDR
Access Type:
Write only
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
–
ABT
ROVR
LINK
TIDLE
7
6
5
4
3
2
1
0
TCOM
TBRE
RTRY
TUND
TOVR
RBNA
RCOM
DONE
• DONE: Management Done Interrupt Disable
• RCOM: Receive Complete Interrupt Disable
• RBNA: Receive Buffer Not Available Interrupt Disable
• TOVR: Transmit Buffer Overrun Interrupt Disable
• TUND: Transmit Buffer Underrun Interrupt Disable
• RTRY: Retry Limit Interrupt Disable
• TBRE: Transmit Buffer Register Empty Interrupt Disable
• TCOM: Transmit Complete Interrupt Disable
• TIDLE: Transmit Idle Interrupt Disable
• LINK: LINK Interrupt Disable
• ROVR: RX Overrun Interrupt Disable
• ABT: Abort Interrupt Disable
0: No effect.
1: Disables the corresponding interrupt.
624
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
36.6.12
Name:
EMAC Interrupt Mask Register
ETH_IMR
Access Type:
Read only
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
–
ABT
ROVR
LINK
TIDLE
7
6
5
4
3
2
1
0
TCOM
TBRE
RTRY
TUND
TOVR
RBNA
RCOM
DONE
• DONE: Management Done Interrupt Mask
• RCOM: Receive Complete Interrupt Mask
• RBNA: Receive Buffer Not Available Interrupt Mask
• TOVR: Transmit Buffer Overrun Interrupt Mask
• TUND: Transmit Buffer Underrun Interrupt Mask
• RTRY: Retry Limit Interrupt Mask
• TBRE: Transmit Buffer Register Empty Interrupt Mask
• TCOM: Transmit Complete Interrupt Mask
• TIDLE: Transmit Idle Interrupt Mask
• LINK: LINK Interrupt Mask
• ROVR: RX Overrun Interrupt Mask
• ABT: Abort Interrupt Mask
0: The corresponding interrupt is enabled.
1: The corresponding interrupt is not enabled.
Important Note: The interrupt is disabled when the corresponding bit is set. This is non-standard for AT91 products as
generally a mask bit set enables the interrupt.
625
1768I–ATARM–09-Jul-09
36.6.13
Name:
EMAC PHY Maintenance Register
ETH_MAN
Access Type:
Read/Write
31
30
LOW
HIGH
23
22
29
21
PHYA
15
28
27
26
RW
25
20
19
18
17
REGA
14
13
24
PHYA
16
CODE
12
11
10
9
8
3
2
1
0
DATA
7
6
5
4
DATA
Writing to this register starts the shift register that controls the serial connection to the PHY. On each shift cycle the MDIO
pin becomes equal to the MSB of the shift register and LSB of the shift register becomes equal to the value of the MDIO
pin. When the shifting is complete an interrupt is generated and the IDLE field is set in the Network Status register.
When read, gives current shifted value.
• DATA
For a write operation this is written with the data to be written to the PHY. After a read operation this contains the data read
from the PHY.
• CODE
Must be written to 10 in accordance with IEEE standard 802.3. Reads as written.
• REGA
Register address. Specifies the register in the PHY to access.
• PHYA
PHY address. Normally is 0.
• RW
Read/Write Operation. 10 is read. 01 is write. Any other value is an invalid PHY management frame.
• HIGH
Must be written with 1 to make a valid PHY management frame. Conforms with IEEE standard 802.3.
• LOW
Must be written with 0 to make a valid PHY management frame. Conforms with IEEE standard 802.3.
626
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
36.6.14
Name:
EMAC Hash Address Low Register
ETH_HSL
Access Type:
31
Read/Write
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
ADDR
23
22
21
20
ADDR
15
14
13
12
ADDR
7
6
5
4
ADDR
• ADDR
Hash address bits 31 to 0.
36.6.15
Name:
EMAC Hash Address High Register
ETH_HSH
Access Type:
31
Read/Write
30
29
28
ADDR
23
22
21
20
ADDR
15
14
13
12
ADDR
7
6
5
4
ADDR
• ADDR
Hash address bits 63 to 32.
627
1768I–ATARM–09-Jul-09
36.6.16
Name:
EMAC Specific Address (1, 2, 3 and 4) High Register
ETH_SA1H,...ETH_SA4H
Access Type:
Read/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
3
2
1
0
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
ADDR
7
6
5
4
ADDR
• ADDR
Unicast addresses (1, 2, 3 and 4), Bits 47:32.
36.6.17
Name:
EMAC Specific Address (1, 2, 3 and 4) Low Register
ETH_SA1L,...ETH_SA4L
Access Type:
31
Read/Write
30
29
28
ADDR
23
22
21
20
ADDR
15
14
13
12
ADDR
7
6
5
4
ADDR
• ADDR
Unicast addresses (1, 2, 3 and 4), Bits 31:0.
628
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
36.6.18 EMAC Statistics Register Block Registers
These registers reset to zero on a read and remain at all ones when they count to their maximum value. They should be
read frequently enough to prevent loss of data.
The statistics register block contains the registers found in Table 36-6.
Table 36-6.
EMAC Statistic Register Block Register Descriptions
Register
Register Name
Description
Frames Transmitted OK Register
ETH_FRA
A 24-bit register counting the number of frames successfully transmitted.
Single Collision Frame Register
ETH_SCOL
A 16-bit register counting the number of frames experiencing a single collision
before being transmitted and experiencing no carrier loss nor underrun.
Multiple Collision Frame
Register
ETH_MCOL
A 16-bit register counting the number of frames experiencing between two and
fifteen collisions prior to being transmitted (62 - 1518 bytes, no carrier loss, no
underrun).
Frames Received OK Register
ETH_OK
A 24-bit register counting the number of good frames received, i.e., address
recognized. A good frame is of length 64 to 1518 bytes and has no FCS,
alignment or code errors.
Frame Check Sequence Error
Register
ETH_SEQE
An 8-bit register counting address-recognized frames that are an integral
number of bytes long, that have bad CRC and that are 64 to 1518 bytes long.
Alignment Error Register
ETH_ALE
An 8-bit register counting frames that:
- are address-recognized,
- are not an integral number of bytes long,
- have bad CRC when their length is truncated to an integral number of bytes,
- are between 64 and 1518 bytes long.
Deferred Transmission Frame
Register
ETH_DTE
A 16-bit register counting the number of frames experiencing deferral due to
carrier sense active on their first attempt at transmission (no underrun or
collision).
Late Collision Register
ETH_LCOL
An 8-bit register counting the number of frames that experience a collision after
the slot time (512 bits) has expired. No carrier loss or underrun. A late collision
is counted twice, i.e., both as a collision and a late collision.
Excessive Collision Register
ETH_ECOL
An 8-bit register counting the number of frames that failed to be transmitted
because they experienced 16 collisions (64 - 1518 bytes, no carrier loss or
underrun).
Transmit Underrun Error
Register
ETH_TUE
An 8-bit register counting the number of frames not transmitted due to a
transmit DMA underrun. If this register is incremented, then no other register is
incremented.
Carrier Sense Error Register
ETH_CSE
An 8-bit register counting the number of frames for which carrier sense was not
detected and that were maintained in half-duplex mode one slot time (512 bits)
after the start of transmission (no excessive collision).
Discard RX Frame Register
ETH_DRFC
This 16-bit counter is incremented every time an address-recognized frame is
received but cannot be copied to memory because no receive buffer is
available.
Receive Overrun Register
ETH_ROV
An 8-bit register counting the number of frames that are address-recognized
but were not copied to memory due to a receive DMA overrun.
Code Error Register
ETH_CDE
An 8-bit register counting the number of frames that are address-recognized,
had RXER asserted during reception. If this counter is incremented, then no
other counters are incremented.
629
1768I–ATARM–09-Jul-09
Table 36-6.
EMAC Statistic Register Block Register Descriptions (Continued)
Register
Register Name
Description
Excessive Length Error Register
ETH_ELR
An 8-bit register counting the number of frames received exceeding 1518 bytes
in length but that do not have either a CRC error, an alignment error or a code
error.
Receive Jabber Register
ETH_RJB
An 8-bit register counting the number of frames received exceeding 1518 bytes
in length and having either a CRC error, an alignment error or a code error.
Undersize Frame Register
ETH_USF
An 8-bit register counting the number of frames received less that are than 64
bytes in length but that do not have either a CRC error, an alignment error or a
code error.
SQE Test Error Register
ETH_SQEE
An 8-bit register counting the number of frames where pin ECOL was not
asserted within a slot time of pin ETXEN being deasserted.
630
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
37. AT91RM9200 Electrical Characteristics
37.1
Absolute Maximum Ratings
Table 37-1.
Absolute Maximum Ratings*
Operating Temperature (Industrial) ........-40⋅ C to +85⋅ C
Storage Temperature ............................ -60°C to +150°C
Voltage on Input Pins
with Respect to Ground ................ -0.3V to VDDIO+0.3V
........................................................................ (+4V max)
*NOTICE:
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to
the device. This is a stress rating only and functional operation of the device at these or other conditions beyond those indicated in the operational
sections of this specification is not implied. Exposure to absolute maximum rating conditions for
extended periods may affect device reliability.
Maximum Operating Voltage
(VDDCORE, VDDPLL and VDDOSC) .................................... 2V
Maximum Operating Voltage
(VDDIOM and VDDIOP) .................................................... 4V
DC Output Current
(SDA10, SDCKE, SDWE, RAS, CAS) .................. 16 mA
DC Output Current
(Any other pin) ........................................................ 8 mA
631
1768I–ATARM–09-Jul-09
37.2
DC Characteristics
The following characteristics are applicable to the operating temperature range: TA = -40°C to 85°C, unless otherwise specified and are certified for a junction temperature up to TJ = 100°C.
Table 37-2.
DC Characteristics
Symbol
Parameter
VDDCORE
DC Supply Core
VDDOSC
Max
Units
1.65
1.95
V
DC Supply Oscillator
1.65
1.95
V
VDDPLL
DC Supply PLL
1.65
1.95
V
VDDIOM
DC Supply Memory I/Os
3.0
3.6
V
VDDIOP
DC Supply Peripheral
I/Os
3.0
3.6
V
VIL
Input Low-level Voltage
-0.3
0.8
V
VIH
Input High-level Voltage
2
VDD + 0.3(1)
V
VOL
Output Low-level Voltage
VOH
Output High-level Voltage
ILEAK
Input Leakage Current
IPULL
Input Pull-up Current
RPULLUP
Internal Pull-up Value
CIN
Input Capacitance
ISC
Notes:
Conditions
Min
Typ
SDA10, SDCKE, SDWE, RAS, CAS
pins:
IOL = 16 mA(2)
IOL = 0 mA(2)
0.4
0.2
Other pins:
IOL = 8 mA(2)
IOL = 0 mA(2)
0.4
0.2
V
SDA10, SDCKE, SDWE, RAS, CAS
pins:
IOH = 16 mA(2)
IOH = 0 mA(2)
VDD - 0.4(1)
VDD - 0.2(1)
Other pins:
IOH = 8 mA(2)
IOH = 0 mA(2)
VDD - 0.4(1)
VDD - 0.2(1)
V
Pullup resistors disabled
1
VDD = 3.0V(1), VIN = 0
µA
8
µA
(1)
VDD = 3.6V , VIN = 0
30
200
kOhm
208-PQFP Package
8.8
256-LFBGA Package
7.6
pF
On VDDCORE = 2V,
MCK = 0 Hz
TA = 25°C
350
2000
All inputs driven TMS,
TDI, TCK, NRST = 1
TA = 85°C
2800
14000
µA
Static Current
1. VDD is applicable to VDDIOM, VDDIOP, VDDPLL and VDDOSC
2. IO = Output Current.
632
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
37.3
Clock Characteristics
These parameters are given in the following conditions:
•
VDDCORE = 1.8V
•
Ambient Temperature = 25°C
The Temperature Derating Factor described in the section 38.1.2 “Temperature Derating Factor” on page 640 and
VDDCORE Voltage Derating Factor described in the section 38.1.3 “VDDCORE Voltage Derating Factor” on page 640 are
both applicable to these characteristics.
37.3.1
Processor Clock Characteristics
Table 37-3.
Processor Clock Waveform Parameters
Symbol
Parameter
1/(tCPPCK)
Processor Clock Frequency
tCPPCK
Processor Clock Period
4.8
ns
tCHPCK
Processor Clock High Half-period
2.2
ns
tCLPCK
Processor Clock Low Half-period
2.2
ns
37.3.2
Conditions
Min
Max
Units
209.0
MHz
Master Clock Characteristics
Table 37-4.
Master Clock Waveform Parameters
Symbol
Parameter
1/(tCPMCK)
Master Clock Frequency
tCPMCK
Master Clock Period
12.5
ns
tCHMCK
Master Clock High Half-period
6.3
ns
tCLMCK
Master Clock Low Half-period
6.3
ns
37.4
Max
Units
80.0
MHz
32 kHz Oscillator Characteristics
Table 37-5.
32 kHz Oscillator Characteristics
Symbol
Parameter
1/(tCP32KHz)
Crystal Oscillator Frequency
Note:
Min
Crystal Oscillator Characteristics
37.4.1
tST
Conditions
Conditions
Min
Typ
Max
32.768
Duty Cycle
Measured at the PCK output pin
Startup Time
VDDOSC = 1.8V
Rs = 50 kΩ, CL = 12.5 pF(1)
40
50
Unit
kHz
60
%
900
ms
1. Rs is the equivalent series resistance, CL is the equivalent load capacitance
633
1768I–ATARM–09-Jul-09
37.4.2
Main Oscillator Characteristics
Table 37-6.
Main Oscillator Characteristics
Symbol
Parameter
Min
Typ
Max
Unit
1/(tCPMAIN)
Crystal Oscillator Frequency
3
16
20
MHz
CL1, CL2
Internal Load Capacitance
(CL1 = CL2)
Integrated load capacitance (XIN,
GND) and (XOUT GND) in series
17
20
23
pF
CL
Equivalent Load Capacitance
Max external capacitors: 10 pF
20
25
pF
Duty Cycle
Measured at the PCK output pin
30
70
%
Startup Time
@ 3 MHz CSHUNT
@ 8 MHz CSHUNT
@ 16 MHz CSHUNT
@ 20 MHz CSHUNT
14.5
4
1.4
1
ms
Drive Level
@ 3 MHz
@ 8 MHz
@ 16 MHz
@ 20 MHz
15
30
50
50
µW
ESR
Equivalent Series Resistor Rs
Fundamental @ 3 MHz
Fundamental @ 8 MHz
Fundamental @ 16 MHz
Fundamental @ 20 MHz
200
100
80
50
Ω
CM
Motional capacitance
8
fF
CSHUNT
Shunt capacitance
7
pF
tST
PON
Conditions
50
= 3 pF
= 7 pF
= 7 pF
= 7 pF
XIN Clock Characteristics (1)
37.4.3
Table 37-7.
XIN Clock Electrical Characteristics
Symbol
Parameter
1/(tCPXIN)
XIN Clock Frequency
tCPXIN
XIN Clock Period
tCHXIN
XIN Clock High Half-period
0.4 x tCPXIN
0.6 x tCPXIN
tCLXIN
XIN Clock Low Half-period
0.4 x tCPXIN
0.6 x tCPXIN
CIN
XIN Input Capacitance
Note (1)
40
pF
XIN Pulldown Resistor
Note (1)
500
kOhm
RIN
Conditions
Min
Max
Units
50.0
MHz
20.0
ns
Notes:
1. These characteristics apply only when the Main Oscillator is in bypass mode (i.e., when MOSCEN = 0 in the CKGR_MOR
register. (See Section 23.6.7 ”PMC Clock Generator Main Oscillator Register” on page 283.)
37.5
Power Consumption
The values in Table 37-8 and Table 37-9 are measured values on the AT91RM9200DK Evaluation Board with operating conditions as follows:
• VDDIO = 3.3V
• VDDCORE = VDDPLL = VDDOSC = 1.8V
• TA = 25⋅ C
• MCK = 60 MHz
634
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
• PCK = 180 Mhz
• SLCK = 32.768 kHz
• EMACK 50 MHz clock not connected
These figures represent the power consumption measured on the VDDCORE power supply.
Table 37-8.
Power Consumption for PMC Modes(1)
Mode
Conditions
Normal
ARM Core clock enabled.
All peripheral clocks deactivated.
24.4
Idle
ARM Core clock disabled and waiting for the next interrupt.
All peripheral clocks deactivated.
13.8
Slow Clock
Main oscillator and PLLs are switched off.
Processor and all peripherals run at slow clock.
1.44
Standby
ARM Core clock disabled and waiting for the next interrupt.
All peripheral clocks deactivated.
Main oscillator and PLLs are switched off.
Slow clock still enabled.
520
Note:
Consumption
µA
Power Consumption by Peripheral (1)
Peripheral
Consumption
PIO Controller
0.5
USART
1.3
MCI
1.6
UDP
1.2
TWI
0.3
SPI
1.2
SSC
1.5
Timer Counter Channel
0.4
UHP
2.5
(2)
PMC
PLL(3)
Slow Clock Oscillator (3)
Main Oscillator (4)
Notes:
mA
1. Code in internal SRAM.
Table 37-9.
EMAC
Unit
Unit
mA
3.5
3144
858
350
uA
nA
uA
1. Code in internal SRAM.
2. Master Clock related power consumption only.
3. Power consumption on the VDDPLL power supply.
4. Power consumption on the VDDOSC power supply.
635
1768I–ATARM–09-Jul-09
37.6
PLL Characteristics
Table 37-10. Phase Lock Loop Characteristics
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
00
80
160
MHz
10
150
180
MHz
00
80
160
MHz
10
150
180
MHz
1
32
MHz
Max
Unit
0.8
V
Field OUTA of CKGR_PLLA
FOUT
Output Frequency
Field OUTB of CKGR_PLLB
FIN
37.7
Input Frequency
Transceiver Characteristics
37.7.1
Electrical Characteristics
Table 37-11. Electrical Parameters
Symbol
Parameter
Conditions
Min
Typ
Input Levels
VIL
Low Level
VIH
High Level
VDI
Differential Input Sensitivity
VCM
Differential Input Common
Mode Range
CIN
Transceiver capacitance
Capacitance to ground on each line
I
Hi-Z State Data Line Leakage
0V < VIN < 3.3V
REXT
Recommended External USB
Series Resistor
In series with each USB pin with ±5%
VOL
Low Level Output
Measured with RL of 1.425 kOhm tied
to 3.6V
VOH
High Level Output
Measured with RL of 14.25 kOhm tied
to GND
2.8
VCRS
Output Signal Crossover
Voltage
Measure conditions described in
Figure 37-1
1.3
|(D+) - (D-)|
2.0
V
0.2
V
0.8
-5
2.5
V
20
pF
+5
µA
0.3
V
27
Output Levels
636
V
2.0
V
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
37.7.2
Switching Characteristics
Table 37-12. In Slow Mode
Symbol
Parameter
Conditions
Min
tFR
Transition Rise Time
CLOAD = 400 pF
tFE
Transition Fall Time
tFRFM
Rise/Fall time Matching
Typ
Max
Unit
75
300
ns
CLOAD = 400 pF
75
300
ns
CLOAD = 400 pF
80
120
%
Max
Unit
Table 37-13. In Full Speed
Symbol
Parameter
Conditions
Min
Typ
tFR
Transition Rise Time
CLOAD = 50 pF
4
20
ns
tFE
Transition Fall Time
CLOAD = 50 pF
4
20
ns
tFRFM
Rise/Fall Time Matching
90
111.11
%
Figure 37-1. USB Data Signal Rise and Fall Times
Rise Time
Fall Time
90%
VCRS
10%
Differential
Data Lines
10%
tR
tF
(a)
REXT=27 ohms
Fosc = 6MHz/750kHz
Buffer
Cload
(b)
637
1768I–ATARM–09-Jul-09
638
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
38. AT91RM9200 AC Characteristics
38.1
38.1.1
Applicable Conditions and Derating Data
Conditions and Timings Computation
The delays are given as typical values in the following conditions:
• VDDIOM = 3.3V
• VDDCORE = 1.8V
• Ambient Temperature = 25°C
• Load Capacitance = 0 pF
• The output level change detection is (0.5 x VDDIOM).
• The input level is (0.3 x VDDIOM) for a low-level detection and is (0.7 x VDDIOM) for a high-level
detection.
The minimum and maximum values given in the AC characteristics tables of this datasheet take
into account process variation and design. In order to obtain the timing for other conditions, the
following equation should be used:
t = δT° × ⎛ ( δVDDCORE × t DATASHEET ) + ⎛ δVDDIOM ×
⎝
⎝
∑( CSIGNAL × δCSIGNAL )⎞⎠ ⎞⎠
where:
• δT° is the derating factor in temperature given in Figure 38-1 on page 640.
• δVDDCORE is the derating factor for the Core Power Supply given in Figure 38-2 on page 640.
• tDATASHEET is the minimum or maximum timing value given in this datasheet for a load
capacitance of 0 pF.
• δVDDIOM is the derating factor for the IOM Power Supply given in Figure 38-3 on page 641.
• CSIGNAL is the capacitance load on the considered output pin(1).
• δCSIGNAL is the load derating factor depending on the capacitance load on the related output
pins given in Min and Max in this datasheet.
The input delays are given as typical values.
Note:
1. The user must take into account the package capacitance load contribution (CIN) described in
Table 37-2, “DC Characteristics,” on page 632.
639
1768I–ATARM–09-Jul-09
38.1.2
Temperature Derating Factor
Figure 38-1. Derating Curve for Different Operating Temperatures
1,2
Derating Factor
1,1
1
0,9
0,8
-40
-20
0
20
40
60
80
Operating Temperature (°C)
VDDCORE Voltage Derating Factor
38.1.3
Figure 38-2. Derating Curve for Different Core Supply Voltages
1,15
Derating Factor
1,1
1,05
1
0,95
0,9
1,65
1,7
1,75
1,8
1,85
1,9
1,95
Core Supply Voltage (V)
640
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
38.1.4
VDDIOM Voltage Derating Factor
Figure 38-3. Derating Curve for Different IO Supply Voltages
1,1
Derating Factor
1,05
1
0,95
0,9
3
3,1
3,2
3,3
3,4
3,5
3,6
I/O Supply Voltage (V)
Note:
The derating factor in this example is applicable only to timings related to output pins.
641
1768I–ATARM–09-Jul-09
38.2
EBI Timings
38.2.1
SMC Signals Relative to MCK
Table 38-1, Table 38-2 and Table 38-3 show timings relative to operating condition limits defined in the section 38.1.1
“Conditions and Timings Computation” on page 639.
Table 38-1.
General-purpose SMC Signals
Symbol
Parameter
SMC1
MCK Falling to NUB Valid
SMC2
MCK Falling to NLB/A0 Valid
SMC3
MCK Falling to A1 - A25 Valid
SMC4
MCK Falling to Chip Select Change
(No Address to Chip Select Setup)
CNCS = 0 pF
SMC5
MCK Falling to Chip Select Active
(Address to Chip Select Setup) (1)
CNCS = 0 pF
Min
Max
Units
CNUB = 0 pF
5.0
7.5
ns
0.028
0.045
ns/pF
4.9
7.5
ns
0.028
0.045
ns/pF
4.9
7.4
ns
0.028
0.045
ns/pF
4.3
6.5
ns
0.028
0.045
ns/pF
(nacss x tCPMCK) + 4.3 (2)
(nacss x tCPMCK) + 6.5 (2)
ns
0.028
0.045
ns/pF
CNUB derating
CNLB = 0 pF
CNLB derating
CADD = 0 pF
CADD derating
SMC6
Chip Select Inactive to MCK Falling
(Address to Chip Select Setup) (1)
SMC7
NCS Minimum Pulse Width
(Address to Chip Select Setup) (1)
SMC8
NWAIT Minimum Pulse Width (1)
Notes:
Conditions
CNCS derating
CNCS derating
CNCS = 0 pF
(nacss x tCPMCK) + 4.4
CNCS derating
CNCS = 0 pF
(2)
-0.028
(nacss x tCPMCK) + 6.5
-0.045
(2)
ns
ns/pF
(((n + 2) - (2 x nacss))
(2) (3)
x tCPMCK)
ns
tCPMCK
ns
1. The derating factor is not to be applied to tCPMCK.
2. nacss = Number of Address to Chip Select Setup Cycles inserted.
3. n = Number of standard Wait States inserted.
642
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
.
Table 38-2.
SMC Write Signals
Symbol
Parameter
Conditions
Min
Max
Units
MCK Rising to NWR Active
(No Wait States) (5)
CNWR = 0 pF
4.8
7.2
ns
SMC10
0.028
0.045
ns/pF
MCK Rising to NWR Active
(Wait States)
CNWR = 0 pF
4.8
7.2
ns
SMC11
0.028
0.045
ns/pF
MCK Falling to NWR Inactive
(No Wait States) (5)
CNWR = 0 pF
4.8
7.2
ns
SMC12
0.028
0.045
ns/pF
MCK Rising to NWR Inactive
(Wait States)
CNWR = 0 pF
4.8
7.2
ns
SMC13
0.028
0.045
ns/pF
4.1
7.9
ns
SMC14
MCK Rising to D0 - D15 Out Valid
0.028
0.044
ns/pF
SMC15
NWR High to NUB Change (5)
SMC16
NWR High to NLB/A0 Change (5)
SMC17
NWR High to A1 - A25 Change (5)
SMC18
NWR High to Chip Select Inactive (5)
SMC19
Data Out Valid before NWR High
(No Wait States) (1) (5)
CNWR derating
CNWR derating
CNWR derating
CNWR derating
CDATA = 0 pF
CDATA derating
CNUB = 0 pF
3.4
ns
0.028
ns/pF
3.7
ns
0.028
ns/pF
3.3
ns
0.028
ns/pF
3.3
ns
0.028
ns/pF
tCHMCK - 0.8
ns
CDATA derating
- 0.044
ns/pF
CNWR derating
0.045
CNUB derating
CNLB = 0 pF
CNLB derating
CADD = 0 pF
CADD derating
CNCS = 0 pF
CNCS derating
C = 0 pF
C = 0 pF
SMC20
Data Out Valid before NWR High
(Wait States) (1) (5)
SMC21
- 0.044
ns/pF
CNWR derating
0.045
ns/pF
tCLMCK - 1.0
ns
CDATA derating
0.044
ns/pF
CNWR derating
- 0.045
ns/pF
tCHMCK - 1.2
ns
CDATA derating
0.044
ns/pF
CNWR derating
- 0.045
C = 0 pF
SMC22
Data Out Valid after NWR High
(Wait States without Hold Cycles) (1) (5)
C = 0 pF
SMC23
Data Out Valid after NWR High
(Wait States with Hold Cycles) (1) (5)
ns
CDATA derating
C = 0 pF
Data Out Valid after NWR High
(No Wait States) (1) (5)
n x tCPMCK - 0.6
ns/pF
(2)
h x tCPMCK - 1.1
ns/pF
(4)
ns
CDATA derating
0.044
ns/pF
CNWR derating
- 0.045
ns/pF
643
1768I–ATARM–09-Jul-09
Table 38-2.
Symbol
SMC Write Signals (Continued)
Parameter
Conditions
SMC24
SMC25
SMC26
SMC27
SMC28
Notes:
NWR Minimum Pulse Width
(No Wait States) (1) (5)
NWR Minimum Pulse Width
(Wait States) (1) (5)
NWR Minimum Pulse Width
(Address to Chip Select Setup Cycles) (1)
Units
ns
CDATA derating
- 0.044
ns/pF
CNCS derating
0.045
C = 0 pF
Data Out Valid after NCS High
(Address to Chip Select Setup Cycles) (1)
Max
(((n + 1) - nacss) x tCPMCK) +
tCHMCK - 1.4 (2) (3)
C = 0 pF
Data Out Valid before NCS High
(Address to Chip Select Setup Cycles) (1)
Min
ns/pF
nacss x tCPMCK - 0.4
(3)
ns
CDATA derating
0.044
ns/pF
CNCS derating
- 0.045
ns/pF
CNWR = 0 pF
tCHMCK - 0.1
ns
0.002
ns/pF
n x tCPMCK (2)
ns
CNWR derating
CNWR = 0 pF
CNWR derating
CNWR = 0 pF
0.002
(n + 1) x tCPMCK
CNWR derating
0.002
ns/pF
(2)
ns
ns/pF
1. The derating factor is not to be applied to tCLMCK, tCHMCK or tCPMCK.
2. n = Number of standard Wait States inserted.
3. nacss = Number of Address to Chip Select Setup Cycles inserted.
4. h = Number of Hold Cycles inserted.
5. Not applicable when Address to Chip Select Setup Cycles are inserted.
644
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table 38-3.
SMC Read Signals
Symbol
Parameter
SMC29
MCK Falling to NRD Active (1) (7)
SMC30
MCK Rising to NRD Active (2)
SMC31
MCK Falling to NRD Inactive (1) (7)
SMC32
MCK Falling to NRD Inactive (2)
SMC33
D0-D15 in Setup before MCK Falling (8)
SMC34
Conditions
Min
Max
Units
CNRD = 0 pF
4.5
6.8
ns
0.028
0.045
ns/pF
4.7
7.0
ns
0.028
0.045
ns/pF
4.5
6.8
ns
0.028
0.045
ns/pF
4.5
6.8
ns
0.028
0.045
ns/pF
CNRD derating
CNRD = 0 pF
CNRD derating
CNRD = 0 pF
CNRD derating
CNRD = 0 pF
CNRD derating
D0-D15 in Hold after MCK Falling
(9)
NRD High to NUB Change (3)
NRD High to NLB/A0 Change
CNUB derating
0.028
0.045
ns/pF
CNRD derating
-0.028
-0.045
ns/pF
(h x tCPMCK) + 0.4 (6)
(h x tCPMCK)
+ 0.7 (6)
ns
CNLB derating
0.028
0.045
ns/pF
CNRD derating
-0.028
-0.045
ns/pF
(h x tCPMCK) + 0.3 (6)
(h x tCPMCK)
+ 0.6 (6)
ns
CADD derating
0.028
0.045
ns/pF
CNRD derating
-0.028
-0.045
ns/pF
(h x tCPMCK) - 0.3 (6)
(h x tCPMCK)
-0.2 (6)
ns
CNCS derating
0.028
0.045
ns/pF
CNRD derating
-0.028
-0.045
ns/pF
(nacss x tCPMCK) + 0.2 (5)
(nacss x tCPMCK)
+ 0.3 (5)
ns
CNCS derating
- 0.028
- 0.045
ns/pF
CNRD derating
0.028
0.045
ns/pF
(3)
NRD High to A1-A25 Change (3)
CNCS = 0 pF
SMC38
NRD High to Chip Select Inactive
(3)
CNCS = 0 pF
SMC39
ns
ns
CADD = 0 pF
SMC37
1.7
(h x tCPMCK)
+ 0.8 (6)
CNLB = 0 pF
SMC36
ns
(h x tCPMCK) + 0.5 (6)
CNUB = 0 pF
SMC35
0.8
Chip Select Inactive to NRD High (3)
SMC40
Data Setup before NRD High (8)
SMC41
Data Hold after NRD High (9)
SMC42
Data Setup before NCS High
CNRD = 0 pF
CNRD derating
CNRD = 0 pF
CNRD derating
CNRD = 0 pF
CNRD derating
7.5
ns
0.045
ns/pF
-3.4
ns
- 0.028
ns/pF
7.3
ns
0.045
ns/pF
645
1768I–ATARM–09-Jul-09
Table 38-3.
SMC Read Signals (Continued)
Symbol
Parameter
SMC43
Data Hold after NCS High
Conditions
Min
CNRD = 0 pF
-3.2
CNRD derating
SMC44
NRD Minimum Pulse Width (1) (3) (7)
SMC45
NRD Minimum Pulse Width (2) (3) (7)
CNRD = 0 pF
n x tCPMCK - 0.02
CNRD = 0 pF
CNRD derating
SMC46
NRD Minimum Pulse Width
CNRD = 0 pF
CNRD derating
Notes:
Units
ns
- 0.028
CNRD derating
(2) (3)
Max
ns/pF
(4)
ns
0.002
ns/pF
n x tCHMCK
+ tCHMCK - 0.2 (4)
ns
0.002
ns/pF
((n + 1) x tCHMCK)
+ tCHMCK- 0.2 (4)
ns
0.002
ns/pF
1. Early Read Protocol.
2. Standard Read Protocol.
3. The derating factor is not to be applied to tCHMCK or tCPMCK.
4. n = Number of standard Wait States inserted.
5. nacss = Number of Address to Chip Select Setup Cycles inserted.
6. h = Number of Hold Cycles inserted.
7. Not applicable when Address to Chip Select Setup Cycles are inserted.
8. Only one of these two timings needs to be met.
9. Only one of these two timings needs to be met.
646
AT91RM9200
1768I–ATARM–09-Jul-09
D0 - D15
to Write
NWR
D0 - D15
Read
NRD(2)
NRD(1)
NUB/NLB/A0
NWAIT
SMC44
SMC1
SMC2
SMC3
SMC35 SMC1
SMC36 SMC2
SMC45
SMC40 SMC41
SMC33 SMC34
SMC29
SMC37
SMC32
A1 - A25
SMC30
SMC38
SMC31
SMC3
SMC15
SMC16
SMC17
SMC18
SMC26
SMC14
NCS
SMC10
SMC4
SMC1
SMC2
SMC3
SMC4
SMC29
SMC4
SMC30
SMC4
SMC12
SMC19
SMC8
SMC40
SMC33
SMC45
SMC44
SMC3
SMC4
SMC35 SMC1
SMC36 SMC2
SMC37
SMC38
SMC4
SMC31
SMC41
SMC34
SMC32
SMC4
SMC21
SMC11
SMC14
1768I–ATARM–09-Jul-09
SMC20
SMC27
SMC4
SMC22
Notes:
SMC1
SMC2
SMC3
SMC4
SMC40
SMC33
SMC45
SMC32
SMC41
SMC34
SMC35
SMC36
SMC37
SMC38
SMC4
SMC1
SMC2
SMC3
SMC4
SMC11
SMC14
MCK
internal
signal
SMC20
SMC27
SMC23
SMC4
AT91RM9200
Figure 38-4. SMC Signals Relative to MCK in Memory Interface Mode
1. Early Read Protocol
2. Standard Read Protocol with or without Setup and Hold Cycles.
647
SMC13
SMC30
SMC13
Notes:
648
D0 - D15
to Write
NWR(2)
D0 - D15
Read
NRD(1)
NUB/NLB/A0
NWAIT
A1 - A25
NCS
SMC30
SMC1
SMC2
SMC3
SMC5
SMC46
SMC7
SMC33
SMC34
SMC42
SMC43
SMC39
SMC6
SMC3
SMC5
SMC11
SMC35 SMC1
SMC36 SMC2
SMC37
SMC32
MCK
internal
signal
SMC14
SMC24
SMC28
SMC7
SMC8
SMC13
SMC25
SMC6
Figure 38-5. SMC Signals Relative to MCK in LCD Interface Mode
1. Standard Read Protocol only.
2. With standard Wait States inserted only.
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
38.2.2
SDRAMC Signals Relative to SDCK
Table 38-4 and Table 38-5 below show timings relative to operating condition limits defined in the section 38.1.1 “Conditions and Timings Computation” on page 639.
Table 38-4.
SDRAMC Clock Signal
Symbol
Parameter
1/(tCPSDCK)
SDRAM Controller Clock Frequency
tCPSDCK
SDRAM Controller Clock Period
12.5
ns
tCHSDCK
SDRAM Controller Clock High Half-Period
5.6
ns
tCLSDCK
SDRAM Controller Clock Low Half-Period
6.9
ns
tMCKtoSDCK_RISING
MCK Rising to SDCK Rising
5.381
8.038
ns
tMCKtoSDCK_FALLING
MCK Falling to SDCK Falling
4.832
7.219
ns
Min
Max
Units
Table 38-5.
Conditions
Min
Max
Units
80.0
MHz
SDRAMC Signals
Symbol
Parameter
SDRAMC1
SDCKE High before SDCK Rising Edge (1)
SDRAMC2
SDCKE Low after SDCK Rising Edge (1)
SDRAMC3
SDCKE Low before SDCK Rising Edge (1)
SDRAMC4
SDCKE High after SDCK Rising Edge (1)
SDRAMC5
SDCS Low before SDCK Rising Edge (1)
SDRAMC6
SDCS High after SDCK Rising Edge (1)
SDRAMC7
RAS Low before SDCK Rising Edge (1)
SDRAMC8
RAS High after SDCK Rising Edge (1)
SDRAMC9
SDA10 Change before SDCK Rising Edge (1)
SDRAMC10
SDA10 Change after SDCK Rising Edge (1)
SDRAMC11
Address Change before SDCK Rising Edge (1)
Conditions
CSDCKE = 0 pF
tCLMCK + 1.2
ns
- 0.015
ns/pF
tCHMCK - 1.4
ns
0.023
ns/pF
tCLMCK + 1.0
ns
- 0.015
ns/pF
tCHMCK - 1.7
ns
0.023
ns/pF
tCLMCK + 1.2
ns
- 0.028
ns/pF
tCHMCK - 1.9
ns
0.045
ns/pF
tCLMCK + 0.6
ns
- 0.015
ns/pF
tCHMCK - 1.1
ns
CRAS derating
0.023
ns/pF
CSDA10 = 0 pF
tCLMCK + 0.8
ns
- 0.015
ns/pF
tCHMCK - 1.2
ns
0.023
ns/pF
tCLMCK + 0.6
ns
- 0.028
ns/pF
CSDCKE derating
CSDCKE = 0 pF
CSDCKE derating
CSDCKE = 0 pF
CSDCKE derating
CSDCKE = 0 pF
CSDCKE derating
CSDCS = 0 pF
CSDCS derating
CSDCS = 0 pF
CSDCS derating
CRAS = 0 pF
CRAS derating
CRAS = 0 pF
CSDA10 derating
CSDA10 = 0 pF
CSDA10 derating
CADD = 0 pF
CADD derating
649
1768I–ATARM–09-Jul-09
Table 38-5.
SDRAMC Signals (Continued)
Symbol
Parameter
Conditions
Min
SDRAMC12
Address Change after SDCK Rising Edge (1)
CADD = 0 pF
tCHMCK - 1.5
ns
0.045
ns/pF
SDRAMC13
Bank Change before SDCK Rising Edge (1)
tCLMCK + 0.8
ns
- 0.028
ns/pF
SDRAMC14
Bank Change after SDCK Rising Edge (1)
tCHMCK - 1.6
ns
CBA derating
0.045
ns/pF
SDRAMC15
CAS Low before SDCK Rising Edge (1)
CCAS = 0 pF
tCLMCK + 0.9
ns
- 0.015
ns/pF
SDRAMC16
CAS High after SDCK Rising Edge (1)
tCHMCK - 1.5
ns
CCAS derating
0.023
ns/pF
SDRAMC17
DQM Change before SDCK Rising Edge (1)
CDQM = 0 pF
tCLMCK + 0.7
ns
- 0.028
ns/pF
SDRAMC18
DQM Change after SDCK Rising Edge (1)
tCHMCK - 1.4
ns
0.045
ns/pF
SDRAMC19
D0-D15 in Setup before SDCK Rising Edge
1.3
ns
SDRAMC20
D0-D15 in Hold after SDCK Rising Edge
0.03
ns
SDRAMC21
D16-D31 in Setup before SDCK Rising Edge
2.0
ns
SDRAMC22
D16-D31 in Hold after SDCK Rising Edge
-0.2
ns
SDWE Low before SDCK Rising Edge
tCLMCK + 1.0
ns
SDRAMC23
- 0.015
ns/pF
SDWE High after SDCK Rising Edge
tCHMCK - 1.8
ns
SDRAMC24
0.023
ns/pF
D0-D15 Out Valid before SDCK Rising Edge
tCLMCK - 2.7
ns
SDRAMC25
-0.044
ns/pF
D0-D15 Out Valid after SDCK Rising Edge
tCHMCK - 2.4
ns
SDRAMC26
0.044
ns/pF
D16-D31 Out Valid before SDCK Rising Edge
tCLMCK - 3.2
ns
SDRAMC27
-0.044
ns/pF
D16-D31 Out Valid after SDCK Rising Edge
tCHMCK - 2.4
ns
SDRAMC28
0.044
ns/pF
CADD derating
CBA = 0 pF
CBA derating
CBA = 0 pF
CCAS derating
CCAS = 0 pF
CDQM derating
CDQM = 0 pF
CDQM derating
CSDWE = 0 pF
CSDWE derating
CSDWE = 0 pF
CSDWE derating
C = 0 pF
CDATA derating
C = 0 pF
CDATA derating
C = 0 pF
CDATA derating
C = 0 pF
Note:
650
CDATA derating
Max
Units
1. The derating factor is not to be applied to tCLMCK or tCHMCK.
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Figure 38-6. SDRAMC Signals Relative to SDCK
SDCK
SDRAMC1
SDRAMC2
SDRAMC3
SDRAMC4
SDCKE
SDRAMC5
SDRAMC6
SDRAMC7
SDRAMC8
SDRAMC5
SDRAMC6
SDRAMC5
SDRAMC6
SDCS
RAS
SDRAMC15 SDRAMC16
SDRAMC15 SDRAMC16
CAS
SDRAMC23 SDRAMC24
SDWE
SDRAMC9 SDRAMC10
SDRAMC9 SDRAMC10
SDRAMC9 SDRAMC10
SDRAMC11 SDRAMC12
SDRAMC11 SDRAMC12
SDRAMC11 SDRAMC12
SDRAMC13 SDRAMC14
SDRAMC13 SDRAMC14
SDRAMC13 SDRAMC14
SDRAMC17 SDRAMC18
SDRAMC17 SDRAMC18
SDA10
A0 - A9,
A11 - A13
BA0/BA1
DQM0 DQM3
SDRAMC19 SDRAMC20
D0 - D15
Read
SDRAMC21 SDRAMC22
D16 - D31
Read
SDRAMC25 SDRAMC26
D0 - D15
to Write
SDRAMC27 SDRAMC28
D16 - D31
to Write
651
1768I–ATARM–09-Jul-09
38.2.3
BFC Signals Relative to BFCK
Table 38-6, Table 38-7 and Table 38-8 show timings relative to operating condition limits defined in the section “Conditions
and Timings Computation” on page 639.
Table 38-6.
Symbol
BFC Clock Signal
Parameter
Conditions
BFCK is MCK
1/(tCPBFCK)
BF Controller Clock Frequency
BF Controller Clock Period
BF Controller Clock High Half-Period
MHz
40.0
MHz
BFCK is MCK/4 (3)
20.0
MHz
BFCK is MCK/2
(1)
12.5
ns
BFCK is MCK/2
(2)
25.0
ns
BFCK is MCK/4
(3)
50.0
ns
6.5
ns
BFCK is MCK/2
(2)
12.8
ns
BFCK is MCK/4
(3)
25.3
ns
6.1
ns
BFCK is MCK/2 (2)
12.3
ns
BFCK is MCK/4 (3)
24.8
ns
BFCK is MCK
tCLBFCK
Notes:
BF Controller Clock Low Half-Period
Units
80.0
BFCK is MCK (1)
tCHBFCK
Max
(2)
BFCK is MCK
tCPBFCK
Min
(1)
(1)
1. Field BFCC = 1 in Register BFC_MR, see Section 20.7.1 “Burst Flash Controller Mode Register” on page 227.
2. Field BFCC = 2 in Register BFC_MR, see Section 20.7.1 “Burst Flash Controller Mode Register” on page 227.
3. Field BFCC = 3 in Register BFC_MR, see Section 20.7.1 “Burst Flash Controller Mode Register” on page 227.
Table 38-7.
BFC Signals in Asynchronous Mode
Symbol
Parameter
BFC1
BFCK Rising to A1-A25 Valid (1)
BFC2
BFCK Rising to A1-A25 Change (1)
BFC3
BFCK Falling to BFAVD Active (1)
BFC4
BFCK Falling to BFAVD Inactive (1)
BFC5
BFAVD Minimum Pulse Width (1)
BFC6
BFCK Rising to BFOE Active
BFC7
BFCK Rising to BFOE Inactive
652
Conditions
Min
CADD = 0 pF
CADD derating
CADD = 0 pF
Max
Units
tCLBFCK - 0.2
ns
0.045
ns/pF
tCLBFCK - 1.0
ns
CADD derating
0.028
ns/pF
CBFAVD = 0 pF
tCLBFCK - 1.1
tCLBFCK - 0.3
ns
0.028
0.044
ns/pF
tCLBFCK - 1.8
tCLBFCK + 0.2
ns
0.028
0.044
ns/pF
CBFAVD derating
CBFAVD = 0 pF
CBFAVD derating
CBFAVD = 0 pF
tCPBFCK + 1.0
ns
CBFAVD derating
0.001
ns/pF
CBFOE = 0 pF
- 0.4
0.1
ns
CBFOE derating
0.028
0.044
ns/pF
CBFOE = 0 pF
- 1.1
0.7
ns
CBFOE derating
0.028
0.044
ns/pF
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table 38-7.
BFC Signals in Asynchronous Mode (Continued)
Symbol
Parameter
BFC8
BFOE Minimum Pulse Width (1)
Conditions
Min
CBFOE = 0 pF
(a x tCPBFCK)
+ 0.9 (2))
ns
0.001
ns/pF
- 0.1
ns
1.0
ns
- 0.9
ns
- 0.044
ns/pF
2.0
ns
CBFOE derating
0.028
ns/pF
CBFWE = 0 pF
- 0.6
- 0.05
ns
CBFWE derating
0.028
0.044
ns/pF
CBFWE = 0 pF
- 1.3
0.5
ns
CBFWE derating
0.028
0.044
ns/pF
tCLBFCK - 0.2
ns
0.044
ns/pF
CBFOE derating
BFC9
D0-D15 in Setup before BFCK Rising Edge
(5)
(6)
BFC10
D0-D15 in Hold after BFCK Rising Edge
BFC11
Data Setup before BFOE High (5)
BFC12
Data Hold after BFOE High (6))
BFC13
BFCK Rising to BFWE Active
BFC14
BFCK Rising to BFWE Inactive
BFC15
BFCK Rising to AD0-AD15 Valid (1) (4)
BFC16
BFCK Rising to AD0-AD15 Not Valid (1) (4)
BFC17
Data Out Valid before BFCK Rising (1) (5)
BFC18
Data Out Valid after BFCK Rising (1) (6)
CBFOE = 0 pF
CBFOE derating
CBFOE = 0 pF
CDATA = 0 pF
CDATA derating
CDATA = 0 pF
ns
0.028
ns/pF
tCLBFCK + 0.5
ns
-0.044
ns/pF
tCHBFCK + 0.7
ns
0.028
ns/pF
tCLBFCK - 0.5
ns
CDATA derating
- 0.028
ns/pF
CBFWE derating
0.044
ns/pF
tCHBFCK + 0.3
ns
CDATA derating
0.028
ns/pF
CBFWE derating
- 0.044
ns/pF
CDATA derating
CDATA = 0 pF
CDATA derating
CDATA = 0 pF
CDATA derating
Data Out Valid before BFWE High (1) (5)
C = 0 pF
BFC20
Data Out Valid after BFWE High (1) (6)
BFC21
Number of Address Valid Latency Cycles (1)
((a + 1) x
tCPBFCK) (2)
((a + 1) x
tCPBFCK) (2)
BFC22
Number of Output Enable Latency Cycles (1)
(o x tCPBFCK)
(o x tCPBFCK)
Notes:
Units
tCLBFCK - 0.8
C = 0 pF
BFC19
Max
(3)
(3)
ns
ns
1. The derating factor is not to be applied to tCPBFCK.
2. a = Number of Address Valid Latency Cycles defined in the BFC_MR AVL field.
3. o = Number of Output Enable Latency Cycles defined in the BFC_MR OEL field.
4. Applicable only with multiplexed Address and Data Buses.
5. Only one of these two timings needs to be met.
6. Only one of these two timings needs to be met.
653
1768I–ATARM–09-Jul-09
Note: 1.
654
D0 - D15
to Write
BFWE
D0 - D15
Read
BFOE
BFAVD
A1 - A25
BFCS(1)
BFCK
internal
signal
BFC15
BFC4
BFC5
BFC3
BFC1
BFC16
BFC21
BFC6
BFC8
BFC9
BFC11
BFC7
BFC22
BFC10
BFC12
BFC15
BFC4
BFC5
BFC3
BFC1
BFC16
BFC13
BFC17
BFC19
BFC21
BFC14
BFC18
BFC20
Figure 38-7. BFC Signals Relative to BFCK in Asynchronous Mode
BFCS is asserted as soon as the BFCOM field in BFC_MR is different from 0.
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table 38-8.
BFC Signals in Burst Mode
Symbol
Parameter
BFC1
BFCK Rising to A1-A25 Valid (1)
BFC2
BFCK Rising to A1-A25 Change (1)
BFC3
BFCK Falling to BFAVD Active (1)
BFC4
BFCK Falling to BFAVD Inactive (1)
BFC5
BFAVD Minimum Pulse Width (1)
BFC6
BFCK Rising to BFOE Active
BFC7
BFCK Rising to BFOE Inactive
BFC9
D0-D15 in Setup before BFCK Rising Edge
BFC10
D0-D15 in Hold after BFCK Rising Edge
BFC15
BFCK Rising to AD0-AD15 Valid (1) (4)
BFC16
BFCK Rising to AD0-AD15 Not Valid (1) (4)
BFC21
Number of Address Valid Latency Cycles (1)
((a + 1) x
tCPBFCK) (2)
((a + 1) x
tCPBFCK) (2)
BFC22
Number of Output Enable Latency Cycles (1)
(o x tCPBFCK)
(o x tCPBFCK)
(3)
ns
BFCK Falling to BFBAA Active (1)
tCLBFCK - 1.0
tCLBFCK - 0.1
ns
BFC23
0.028
0.044
ns/pF
BFCK Falling to BFBAA Inactive (1)
tCLBFCK - 1.7
tCLBFCK + 0.1
ns
BFC24
0.028
0.044
ns/pF
BFC25
BFRDY Change Hold after BFCK Rising Edge
0.1
ns
BFC26
BFRDY Change Setup before BFCK Rising Edge
0.3
ns
Notes:
Conditions
Min
CADD = 0 pF
CADD derating
CADD = 0 pF
Max
Units
tCLBFCK - 0.2
ns
0.045
ns/pF
tCLBFCK - 1.0
ns
CADD derating
0.028
ns/pF
CBFAVD = 0 pF
tCLBFCK - 1.1
tCLBFCK - 0.3
ns
0.028
0.044
ns/pF
tCLBFCK - 1.8
tCLBFCK + 0.2
ns
0.028
0.044
ns/pF
CBFAVD derating
CBFAVD = 0 pF
CBFAVD derating
CBFAVD = 0 pF
tCPBFCK + 1.0
ns
CBFAVD derating
0.001
ns/pF
CBFOE = 0 pF
- 0.4
0.1
ns
CBFOE derating
0.028
0.044
ns/pF
CBFOE = 0 pF
- 1.1
0.7
ns
CBFOE derating
0.028
0.044
ns/pF
- 0.1
ns
1.0
ns
CDATA = 0 pF
CDATA derating
CDATA = 0 pF
0.044
ns/pF
ns
0.028
ns/pF
(3)
CBFBAA derating
CBFBAA = 0 pF
ns
tCLBFCK - 0.8
CDATA derating
CBFBAA = 0 pF
tCLBFCK - 0.2
CBFBAA derating
ns
1. The derating factor is not to be applied to tCPBFCK.
2. a = Number of Address Valid Latency Cycles defined in the BFC_MR AVL field.
3. o = Number of Output Enable Latency Cycles defined in the BFC_MR OEL field.
4. Applicable only with multiplexed Address and Data Buses.
655
1768I–ATARM–09-Jul-09
D0 - D15
to Write if
multiplexed
bus only
D0 - D15
Read
BFOE
BFRDY
BFAVD
A1 - A25
BFCS(1)
BFC15
BFC4
BFC5
BFC3
BFC1
BFC16
BFC21
BFC6
BFC25
BFC9
BFCK
if clock controlled
address advance
BFC26
BFC25
BFC26
BFC7
BFC24
BFC10
BFBAA
if signal controlled
address advance
BFC23
BFC22
BFC6
BFC23
BFC10
BFC9
BFC9
BFC10
BFC9
656
BFC7
BFC24
BFC9
Note: 1.
BFC10
BFCK
if signal controlled
address advance
Figure 38-8. BFC Signals Relative to BFCK in Burst Mode
BFCS is asserted as soon as the BFCOM field in BFC_MR is different from 0.
AT91RM9200
1768I–ATARM–09-Jul-09
BFC10
BFC9
BFC10
BFC9
BFC10
BFC9
BFC10
BFC9
BFC9
BFC10
BFC10
BFC9
AT91RM9200
38.3
38.3.1
JTAG/ICE Timings
ICE Interface Signals
Table 38-9 shows timings relative to operating condition limits defined in the section Section
38.1.1 “Conditions and Timings Computation” on page 639
Table 38-9.
ICE Interface Timing Specifications
Symbol
Parameter
Conditions
ICE0
NTRST Minimum Pulse Width
20.00
ns
ICE1
NTRST High Recovery to TCK High
0.86
ns
ICE2
NTRST High Removal from TCK
High
0.90
ns
ICE3
TCK Low Half-period
8.00
ns
ICE4
TCK High Half-period
8.00
ns
ICE5
TCK Period
20.00
ns
ICE6
TDI, TMS, Setup before TCK High
-0.13
ns
ICE7
TDI, TMS, Hold after TCK High
0.10
ns
4.17
ns
ICE8
TDO Hold Time
0
ns/pF
ICE9
TCK Low to TDO Valid
CTDO = 0 pF
Min
CTDO derating
Max
Units
CTDO = 0 pF
6.49
ns
CTDO derating
0.028
ns/pF
Figure 38-9. ICE Interface Signals
ICE0
NTRST
ICE1
ICE2
ICE5
TCK
ICE4
ICE3
TMS/TDI
ICE6
ICE7
TDO
ICE8
ICE9
657
1768I–ATARM–09-Jul-09
38.3.2
JTAG Interface Signals
Table 38-10 shows timings relative to operating condition limits defined in the section 38.1.1
“Conditions and Timings Computation” on page 639.
Table 38-10. JTAG Interface Timing Specifications
658
Symbol
Parameter
Conditions
JTAG0
NTRST Minimum Pulse Width
20.00
ns
JTAG1
NTRST High Recovery to TCK High
-0.16
ns
JTAG2
NTRST High Recovery to TCK Low
-0.16
ns
JTAG3
NTRST High Removal from TCK High
-0.07
ns
JTAG4
NTRST High Removal from TCK Low
-0.07
ns
JTAG5
TCK Low Half-period
8.00
ns
JTAG6
TCK High Half-period
8.00
ns
JTAG7
TCK Period
20.00
ns
JTAG8
TDI, TMS Setup before TCK High
0.01
ns
JTAG9
TDI, TMS Hold after TCK High
3.21
ns
2.38
ns
JTAG10
TDO Hold Time
0
ns/pF
JTAG11
TCK Low to TDO Valid
JTAG12
Device Inputs Setup Time
-1.23
ns
JTAG13
Device Inputs Hold Time
3.81
ns
7.15
ns
JTAG14
Device Outputs Hold Time
0
ns/pF
JTAG15
TCK to Device Outputs Valid
CTDO = 0 pF
CTDO derating
Min
Max
Units
CTDO = 0 pF
4.66
ns
CTDO derating
0.028
ns/pF
COUT = 0 pF
COUT derating
COUT = 0 pF
7.22
ns
COUT derating
0.028
ns/pF
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Figure 38-10. JTAG Interface Signals
JTAG0
NTRST
JTAG1
JTAG2
JTAG5
TCK
JTAG3
JTAG4
TMS/TDI
JTAG6
JTAG7
JTAG10
JTAG11
TDO
JTAG8
JTAG9
Device
Inputs
Device
Outputs
JTAG12
JTAG13
659
1768I–ATARM–09-Jul-09
38.4
ETM Timings
38.4.1
Timings Data
Table 38-11 shows timings relative to operating condition limits defined in the section 38.1.1
“Conditions and Timings Computation” on page 639.
Table 38-11. ETM Timing Characteristics
Symbol
Parameter
Conditions
Min
1/(tCPTCLK)
Trace Clock Frequency
tCPTCLK
Trace Clock Period
tCHTCLK
TCLK High Half-period
tCPTCLK/2 + 0.02
ns
tCLTCLK
TCLK Low Half-period
tCPTCLK/2 - 0.02
ns
ETM0
Data Signals Out Valid
before TCLK Rising Edge
tCLTCLK - 1.06
ns
Data Signals Out Valid after
TCLK Rising Edge
tCHTCLK - 0.49
ns
ETM1
0.044
ns/pF
ETM2
Data Signals Out Valid
before TCLK Falling Edge
tCHTCLK - 1.03
ns
Data Signals Out Valid after
TCLK Falling Edge
tCLTCLK - 0.51
ns
ETM3
0.044
ns/pF
11.56
C = 0 pF
CDATA derating
C = 0 pF
CDATA derating
Typ
Max
Units
1/(2 x tCPPCK)
86.54
MHz
2 x tCPPCK
ns
Figure 38-11. ETM Signals
tCHTCLK
TCLK
tCLTCLK
tCPTCLK
38.4.2
ETM3
ETM2
ETM1
ETM0
TSYNC
TPS[2:0]
TPK[15:0]
Design Considerations
When designing a PCB, it is important to keep the differences between trace length of ETM signals as small as possible to minimize skew between them. In addition, crosstalk on the trace port
must be kept to a minimum as it can cause erroneous trace results. Stubs on these traces can
cause unpredictable responses, thus it is recommended to avoid stubs on the trace lines.
The TCLK line should be series-terminated as close as possible to the microcontroller pins.
The maximum capacitance presented by the trace connector, cabling and interfacing logic must
be less than 15 pF.
660
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
39. AT91RM9200 Mechanical Characteristics
39.1
39.1.1
Thermal and Reliability Considerations
Thermal Data
Table 39-1 summarizes the thermal resistance data depending on the package.
Table 39-1.
Thermal Resistance Data
Symbol
Parameter
θJA
Junction-to-ambient thermal resistance
Condition
Package
Typ
PQFP208
33.9
LFBGA256
35.6
PQFP208
15.7
LFBGA256
7.7
Unit
Still Air
°C/W
θJC
39.1.2
Junction-to-case thermal resistance
Reliability Data
The number of gates and the device die size are provided Table 39-2 so that the user can calculate reliability data for another standard and/or in another environmental model.
Table 39-2.
Reliability Data
Parameter
Data
Unit
Number of Logic Gates
4461
K gates
Number of Memory Gates
2458
K gates
Device Die Size
33.9
mm2
661
1768I–ATARM–09-Jul-09
39.1.3
Junction Temperature
The average chip-junction temperature, TJ, in °C can be obtained from the following:
1. T J = T A + ( P D × θ JA )
2. T J = T A + ( P D × ( θ HEATSINK + θ JC ) )
where:
• θJA = package thermal resistance, Junction-to-ambient (°C/W), provided in Table 39-1 on
page 661.
• θJC = package thermal resistance, Junction-to-case thermal resistance (°C/W), provided in
Table 39-1 on page 661.
• θHEAT SINK = cooling device thermal resistance (°C/W), provided in the device datasheet.
• PD = device power consumption (W) estimated from data provided in the section 37.5 “Power
Consumption” on page 634.
• TA = ambient temperature (°C).
From the first equation, the user can derive the estimated lifetime of the chip and decide if a
cooling device is necessary or not. If a cooling device is to be fitted on the chip, the second
equation should be used to compute the resulting average chip-junction temperature TJ in °C.
39.2
Package Drawings
Figure 39-1. 208-pin PQFP Package Drawing
C
662
C1
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table 39-3.
208-pin PQFP Package Dimensions (in mm)
Symbol
Min
c
0.11
c1
0.11
L
0.65
Nom
Max
Symbol
Min
Nom
Max
0.23
b1
0.17
0.20
0.23
0.15
0.19
ddd
0.10
0.88
1.03
L1
Tolerances of Form and Position
1.60 REF
aaa
0.3
0.25
R2
0.13
ccc
0.1
R1
0.13
S
0.4
D
31.20
A
4.10
D1
28.00
A1
0.25
0.50
E
31.20
A2
3.20
3.60
E1
28.00
b
0.17
0.27
e
0.50
BSC
3.40
Table 39-4.
Device and 208-pin Package Maximum Weight
Package Type
Weight
Unit
Standard and Green
5809
mg
Table 39-5.
208-pin PQFP
Package Type
Moisture Sensitivity Level
Standard and Green
3
Table 39-6.
Package Reference
Package Type
Standard
Standard
JEDEC Drawing MS-022
JEDEC Drawing MS-212
Green
JESD97 Classification: e2
The Green package respects the recommendations of the NEMI User Group.
663
1768I–ATARM–09-Jul-09
Figure 39-2. 256-ball BGA Package Drawing
Table 39-7.
Device and 256-ball BGA Package Maximum Weight
Package Type
Weight
Unit
620
mg
Standard
RoHS-compliant
Table 39-8.
256-ball BGA Package Characteristics
Package Type
Moisture Sensitivity Level
Standard and RoHS-compliant
3
Table 39-9.
Package Reference
Package Type
Standard
Standard
JEDEC Drawing MO-205E
JEDEC Drawing MO-205E
RoHS-compliant
JESD97 Classification: e1
The RoHS-compliant package respects the recommendations of the NEMI User Group.
664
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
39.3
39.3.1
Soldering Profiles
Standard Packages
Table 39-10 gives the recommended soldering profile from J-STD-20.
Table 39-10. Soldering Profile
Convection or
IR/Convection
VPR
Average Ramp-up Rate (183⋅ C to Peak)
3⋅ C/sec. max.
10⋅ C/sec.
Preheat Temperature 125⋅ C ±25⋅ C
120 sec. max
Temperature Maintained Above 183⋅ C
60 sec. to 150 sec.
Time within 5⋅ C of Actual Peak Temperature
10 sec. to 20 sec.
60 sec.
Peak Temperature Range
220 +5/-0⋅ C or
235 +5/-0⋅ C
215 to 219⋅ C or
235 +5/-0⋅ C
Ramp-down Rate
6⋅ C/sec.
10⋅ C/sec.
Time 25⋅ C to Peak Temperature
6 min. max
Small packages may be subject to higher temperatures if they are reflowed in boards with larger
components. In this case, small packages may have to withstand temperatures of up to 235⋅ C,
not 220⋅ C (IR reflow).
Recommended package reflow conditions depend on package thickness and volume. See
Table 39-11.
Table 39-11. Recommended Package Reflow Conditions (LQFP and BGA)(1) (2)(3)
Parameter
Temperature
Convection
220 +5/-0⋅ C
VPR
215 to 219⋅ C
IR/Convection
220 +5/-0⋅ C
Notes:
1. The packages are qualified by Atmel by using IR reflow conditions, not convection or VPR.
2. By default, the package level 1 is qualified at 220⋅ C (unless 235⋅ C is stipulated).
3. The body temperature is the most important parameter but other profile parameters such as
total exposure time to hot temperature or heating rate may also influence component reliability.
A maximum of three reflow passes is allowed per component.
665
1768I–ATARM–09-Jul-09
39.3.2
Green and RoHS-compliant Packages
Table 39-12 gives the recommended soldering profile from J-STD-20.
Table 39-12. Soldering Profile
Profile Feature
PQFP208
Green Package (1)(2)
BGA256 RoHS
Compliant Package (3)
Average Ramp-up Rate (183⋅ C to Peak)
3⋅ C/sec. max.
3⋅ C/sec. max
Preheat Temperature 175⋅ C ±25⋅ C
180 sec. max
180 sec. max
Temperature Maintained Above 217⋅ C
60 sec. to 150 sec.
60 sec. to 150 sec.
Time within 5⋅ C of Actual Peak Temperature
20sec. to 40 sec.
20 sec. to 40 sec.
Peak Temperature Range
260⋅ C
260⋅ C
Ramp-down Rate
6⋅ C/sec. max
6⋅ C/sec. max
Time 25⋅ C to Peak Temperature
8 min. max
8 min. max
Notes:
1. The package is certified to be backward compatible with Pb/Sn soldering profile.
2. Atmel Green Definition is: RoHS and <900ppm Br; <900ppm Sb; no TBTO use, no Phosphorous use.
3. It is recommended to apply a soldering temperature higher than 250°.
666
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
667
1768I–ATARM–09-Jul-09
668
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
40. AT91RM9200 Ordering Information
Table 40-1.
Ordering Information
Ordering Code
Package
Package Type
Temperature Operating Range
AT91RM9200-QU-002
PQFP 208
Green
AT91RM9200-CJ-002
BGA 256
RoHS-compliant
Industrial
(-40° C to 85° C)
669
1768I–ATARM–09-Jul-09
670
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
41. AT91RM9200 Errata
41.1
Marking
All devices are marked with the Atmel logo and the ordering code.
Additional marking may be in one of the following formats:
YYWW
V
XXXXXXXXX
ARM
where
• “YY”: manufactory year
• “WW”: manufactory week
• “V”: revision
• “XXXXXXXXX”: lot number
ZZZZZZ YYWW
XXXXXXXXX
ARM
where
• “ZZZZZZ”: manufactory number
• “YY”: manufactory year
• “WW”: manufactory week
• “XXXXXXXXX”: lot number
671
1768I–ATARM–09-Jul-09
41.2
41.2.1
EBI
A24 not wired internally between the EBI and the PIO
A24 is not wired internally between the EBI and the PIO. Use only PIO mode on it.
Problem Fix/Workaround
Due to this error, static memories over 16M bytes per chip select cannot be used. To interface
32-Mbyte memories and over, the user must use two memory chips connected on two different
chip selects.
41.3
41.3.1
EMAC
Using Receive frames and buffers not word-aligned
A dead lock may appear when the Ethernet MAC attempts to store a new received valid frame
while there are no more rx buffer descriptors. This appears only when the received frame length
is not a multiple of 4 bytes. In this configuration, even if the application enables new receive buffer descriptors, all packets will be rejected.
Problem Fix/Workaround
The software workaround is to disable and re-enable the receive function in the network function
register ETH_CTL each time a buffer is not available (RBNA in the status register).
ETH CTL &= ~0x00000004 ;
ETH CTL |=
0x00000004 ;
Note that an interrupt can be activated for the RBNA detection.
Another workaround is to align the address of the receive buffer descriptor on a boundary of 16
Words (address 0xaaaa aa00, 0xaaaa aa40, 0xaaaa aa80,.....)
41.4
41.4.1
MCI
Data Endianess inversion from the MCI to MMC or SD Card
The data endianess is inverted when writing or reading to or from an MMC or SD card. If the MCI
interface is exclusively used to read/write from/to a dedicated card the inversion is not visible
(two inversions). Furthermore, if the card is shared with other systems then endianess will not
match. This endianess inversion concerns only data sectors and not command and response.
Problem Fix/Workaround
A software workaround consists of swapping the order of word bytes before writing and after
reading.
41.4.2
Data Timeout Error Flag
As the data timeout error flag cannot rise, the MCI is stalled indefinitely waiting for the data start
bit.
Problem Fix/Workaround
A STOP command must be sent with a software timeout.
41.4.3
672
STREAM command not supported
The STREAM READ/WRITE commands are not supported by the MCI.
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Problem Fix/Workaround
None.
41.4.4
STOP during a WRITE_MULTIPLE_BLOCK command
The WRITE_MULTIPLE_BLOCK with a transfer size (PDC) not a multiple of the block length is
not stopped by the STOP command.
Problem Fix/Workaround
Choose an appropriate size for the block length.
41.4.5
DTIP flag
The DTIP flag is not reset if STOP_COMMAND is received in the middle of a block data transfer.
Problem Fix/Workaround
None.
41.4.6
STOP command with SYNCHRONISED special command
A STOP command with SYNCHRONISED special command is sent after the block data transfer
ends. During this time the MMCI receives data but the RXRDY flag is no longer asserted.
Problem Fix/Workaround
Do not send a STOP command with SYNCHRONISED special command.
41.4.7
Data FIFO and status bits
Do not read/write the Data FIFO if RXRDY/TXRDY status bits are not set.
Problem Fix/Workaround
None.
41.4.8
DATA FIFO problem with PDC
The shared FIFO is reset at the beginning of a transfer command.
Problem Fix/Workaround
So as to avoid losing data, it is mandatory to enable the PDC channel after writing to the command register. In order to achieve this sequence correctly, it is mandatory to disable all IT
sources.
41.4.9
DATA_CRC_ERR flag never rises
The DATA_CRC_ERR (error flag) never rises during the checking of bad data CRC status sent
by MMC/SD card after block writing.
Problem Fix/Workaround
CRC must be done by software.
41.4.10
STOP during a READ_MULTIPLE_BLOCK command
If the user sends a READ_MULTIPLE_BLOCK command and stops it by using a
STOP_COMMAND in the middle of a data block transfer then the internal state of the MMCI
controller stops in a bad state.After that the following read block (with READ_SINGLE_BLOCK
or READ_MULTIPLE_BLOCK) will be entirely corrupted.
673
1768I–ATARM–09-Jul-09
Problem Fix/Workaround
It consists in doing a software reset if RXRDY = 1 after the STOP_COMMAND. This flag indicates that the MMCI receives more data than the PDC has been settle to transfer. After this soft
reset the MCI_CR, MCI_MR, MCI_DTOR, MCI_SDCR need to be reassigned.
41.4.11
Data write operation and number of bytes
The Data Write operation with a number of bytes less than 12 is impossible.
Problem Fix/Workaround
The PDC counters must always be equal to 12 bytes for data transfers lower than 12 bytes. The
BLKLEN or BCNT field are used to specify the real count number.
41.5
41.5.1
PIO
NWAIT activity depends on use of PC6
NWAIT activity depends on use of PC6. The PC6 line multiplexes with the NWAIT function. As
the PIO Controller is transparent in input, the level on the PC6 line has direct impact on the
behavior of the EBI. In particular, driving the PC6 line to 0 might lead to a deadlock of the
system.
Problem Fix/Workaround
Use PC6 carefully. In general, it is recommended to not use PC6 and to make sure the pull-up is
enabled.
41.5.2
Output Data Status Register is always Read/Write
The programming of the register PIO_OWSR has no effect on the read/write features of
PIO_ODSR, which is always read/write accessible.
Problem Fix/Workaround
None.
41.6
41.6.1
PMC
Constraints on the Master Clock selection sequence
The PMC_MCKR register must not be programmed in a single write operation.
Problem Fix/Workaround
The preferred programming sequence for the PMC_MCKR register is as follows:
1. Program the CSS field in the PMC_MCKR.
2. Wait for the MCKRDY bit to be set in the PMC_SR register.
3. Program the PRES field (in the PMC_MCKR).
An exception to this sequence occurs when the processor clock frequency is greater than the
master clock frequency. In this case, the PRES field should be written first.
41.6.2
674
MCKRDY does not rise in some cases
When re-programming the Master Clock Register, if both fields PRES and CSS are written with
the same values as the ones already stored, or if both fields are written with different values than
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
the ones already stored, the status bit MCKRDY does not rise. When one and only one of the
fields PRES and CSS is changed, the MCKRDY bit operates normally.
Problem Fix/Workaround
If both fields must be re-programmed, carry out the change in two steps.
41.6.3
PMC, Clock Generator: Bad switching when writing PLL registers with same MUL and DIV values
When the fields MUL and DIV in the CKGR_PLLBR register are written with the same values as
already programmed, the Master Clock signal switches to Main Clock (output of the Main Oscillator) until a different value is programmed in the register.
When the fields MUL and DIV in the CKGR_PLLAR register are written with the same values as
already programmed, the Master Clock signal switches to Slow Clock (output of the 32768 Hz
Oscillator) until a different value is programmed in the register.
Problem Fix/Workaround
The user must be sure that either the DIV or MUL field changes when setting the CKGR_PLLBR
or CKGR_PLLAR register.
41.6.4
OSCBYPASS is not functional with PLLA
With PLLA, it is not possible to have an MCKRDY flag raised.
Problem Fix/Workaround
Even if MCKRDY flag does not raise with PLLA, it will not prevent you from switching on it.
You just need to wait for the PLLA lock time; for that program, PLLA then PLLB. When PLLB is
ready, PLLA is ready too.
Main Oscillator in Bypass Mode: CKGR_MOR = 0x00000002
PLLA programming: CKGR_PLLAR = 0x20063E01
PLLB programming: CKGR_PLLBR = 0x10173F05
Wait PLLB LOCKB bit: PMC_SR will be 0x0000000C
Switch on PLLACK clock: PMC_MCKR -> 0x00000102
PMC_SR will be 0x0000000C
41.7
ROM Bootloader
ROM Bootloader: Limitation with 8-bit parallel memories.
Limitation with 8-bit parallel memories. In the internal Boot Rom program, version 1.0, the wait
state number on CS0 is set to 0 during Boot ROM initialization. This gives an access time of 20
ns at 48 MHz Master Clock Frequency. This limitation of the ROM Bootloader applies to
AT91RM9200 with the product number 58A07F.
Problem Fix/Workaround
None.
675
1768I–ATARM–09-Jul-09
41.8
41.8.1
SDRAMC
SDRC_IMR can be written
The Interrupt Mask Register in the SDRAM Controller is not read-only. Thus, writing to it modifies the contents instead of having no effect.
Problem Fix/Workaround
None.
41.8.2
No wrap-around for SDRAM devices with two internal banks
In the case of SDRAM devices featuring two internal banks, when the physical address is higher
than the memory size, the SDRAM controller does not wrap around. It activates virtual bank
numbers three or four.
Problem Fix/Workaround
None.
41.8.3
No tRC after refresh when low-power mode is enabled
When low-power mode is enabled and after a refresh command is sent to the SDRAM, the
SDRAM Controller enters low-power mode by asserting SDCKE low. The tRC timing between
Auto-refresh and Low-power mode is not respected. As SDCKE is low, the INHIBIT and NOP
commands are not sent to the SDRAM.
For the moment this warning has no effect on the correct functionality of the SDRAM.
Problem Fix/Workaround
None.
41.8.4
Some devices are not supported
The SDRAM controller does not support the following devices in 32-bit mode:
• 128 Mbit device: 32M*4bits: 4 banks/12 rows/11 columns
• 256 Mbit device: 64M*4bits: 4 banks/13 rows/11 columns
Problem Fix/Workaround
None.
41.8.5
Interrupt Disable Register
Writing 0 to the Interrupt Enable Register or to the Interrupt Disable Register modifies the value
of Interrupt Mask Register.
Problem Fix/Workaround
None.
41.9
41.9.1
SMC
Address Bus continuously active
The address bus is continuously driven with the address of the current access, even if it is an
internal one.
Problem Fix/Workaround
676
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
None.
41.9.2
16-bit write access constraints
When at least two SMC_CSR registers are programmed as follows:
– SMC_SCRx: With wait states (1 < NWS < 127), 16-bit data bus width, and byte write
access (BAT field set to 0)
– SMC_CSRy: With wait states (1 < NWS < 127), 16-bit data bus width, and byte
select access (BAT field set to 1),
the associated NCSx signal is not asserted for the write access.
Problem Fix/Workaround
For registers programmed with wait states and 16-bit data bus width configuration, the BAT
fields in these registers must be programmed with the same value.
41.10 SPI
41.10.1
Slave Mode Receiver does not mask the highest data bits
If the SPI receives a frame followed by 8 bits of data, the user needs to mask the highest byte of
the Receive Holding Register, as this data may be incorrect and not 0.
Problem Fix/Workaround
The user should implement the PDC. If the PDC is not implemented, the user should mask the
highest byte of the Receive Holding register.
41.10.2
No chip select configuration change before end of current transfer
If the SPI is programmed in Master Mode and in Fixed Peripheral Mode, and data is being sent
to a slave, the user has to wait for completion of the transfer before changing the slave number.
Programming a new slave number (PCS) and/or a new DLYBCS field locks the SPI on the current slave.
Problem Fix/Workaround
The user should use the Variable Peripheral Mode.
41.10.3
NPCSx rises if no data is to be transmitted
If the SPI has sent all the data written in the SPI_TDR, the current NPCS rises immediately. This
might be inconvenient in the case of several SPI peripherals requiring their chip select line to
remain active until a complete data buffer has been transmitted. The PDC channel may be late
in providing data to be transmitted when bus latencies are too high.
Problem Fix/Workaround
For high-speed applications, the relevant PIO pins can be used to manage the data
transmission.
41.10.4
Mode Fault does not allow more than one Master on Chip Select 0
If Mode fault is disabled, Chip Select 0 cannot be driven by a component other than the SPI otherwise the transfer does not occur.
Problem Fix/Workaround
None.
677
1768I–ATARM–09-Jul-09
41.11 SSC
41.11.1
Receiver does not take into account a start condition while receiving data
The SSC receiver does not support reception of the last data sequence of a frame that overlaps
a new start of frame, regardless of the mode of detection of the start condition. For example, this
prevents reception of the last data of a TDM bus.
Problem Fix/Workaround
None.
41.11.2
RXSYN and TXSYN not cleared when read
The status bits RXSYN and TXSYN are active during a complete serial clock period and are not
immediately cleared when SSC_SR is read.
Problem Fix/Workaround
The user must enable the interrupt relevant to RXSYN and TXSYN.
41.11.3
Receiver Speed Limitations
– If RF is programmed as input, the maximum clock frequency is MCK divided by 2.
– If RF is programmed as output and RK is programmed as input, the maximum clock
frequency is MCK divided by 6.
– If RF and RK are both programmed as output, the maximum clock frequency is MCK
divided by 4.
Problem Fix/Workaround
None.
41.11.4
Transmitter Speed Limitations
– If both TF and TK are programmed as output, the maximum clock frequency is MCK
divided by 4.
– If TF is programmed in output and TK is programmed as input, the maximum clock
frequency is MCK divided by 8.
– If both TF and TK are programmed as input, the maximum clock frequency is MCK
divided by 8.
– If TF is programmed in input and TK is programmed as output, the maximum clock
frequency is MCK divided by 4.
Problem Fix/Workaround
None.
41.11.5
Disabling the SSC does not stop the Frame Synchronization signal generation
Generating RF can be stopped only by programming the FSOS field in SSC_RFMR to 0x0.
Generating TF can be stopped only by programming the FSOS field in SSC_TFMR to 0x0.
Problem Fix/Workaround
None.
678
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
41.11.6
No delay when start condition overlays data transmit
When transmission of data is programmed at the end of a frame and the start condition of the
following frame is detected at the end of the current frame, the delay programmed by the
STTDLY bit (in the SSC_RCMR and in the SSC_TCMR registers) is not performed on the next
frame. Transmission starts immediately regardless of the programming of the field STTDLY.
Problem Fix/Workaround
None.
41.11.7
Unexpected delay on TD output
When SSC is configured with the following conditions:
• TCMR.STTDLY more than 0
• RCMR.START = Start on falling edge / Start on Rising edge / Start on any edge
• RFMR.FSOS = None (input)
• TCMR.START = Receive Start
An unexpected delay of 2 or 3 system clock cycles is added to TD output.
Problem Fix/Workaround
None.
41.12 TC
41.12.1
Wrong Compare at restart if burst low
If the counter was stopped or disabled, unwanted Compare RA, RB or RC may occur at restart if
the clock selected by the counter is masked by a low selected burst input when the trigger event
is recognized at the selected clock active edge. All compare effects are affected, as the flags are
set incorrectly and CPC trigger, CPC stop or CPC disable may occur.
Problem Fix/Workaround
None.
41.12.2
Wrong 0 captured before Compare RC trigger
A wrong 0 is captured in RA or RB during the last selected counter clock period if CPCTRG is
active and the capture event occurred at least one Master Clock cycle after the last counter
value update.
Problem Fix/Workaround
None.
41.12.3
Erroneous capture with burst low
The value captured is not equal to the Counter Value if the selected burst input is low at capture
time, i.e., at the selected clock active edge where the capture event is recognized.
The captured value may be 0; otherwise, it is the Counter Value plus one instead of the Counter
Value.
Problem Fix/Workaround
None.
679
1768I–ATARM–09-Jul-09
41.12.4
Bad capture at restart if burst low
The captured value is not zero if burst is low when the preceding trigger event is recognized.
Instead, the captured value is the Counter Value before the trigger.
Problem Fix/Workaround
None.
41.12.5
TIOA and TIOB outputs stuck in case of simultaneous events
In the register TC_CMR, if at least one of the fields ASWTRG or AEEVT or ACPC is set to 0x0
(none), the event programmed by ACPA is not carried out.
In the register TC_CMR, if at least one of the fields ASWTRG or AEEVT is set to 0x0 (none), the
event programmed by ACPC is not carried out.
In the register TC_CMR, if the field ASWTRG is set to 0x0 (none), the event programmed by
AEEVT is not carried out.
The same problem exists on the TIOB output with the fields BSWTRG, BEEVT, BCPC and
BCPB.
Problem Fix/Workaround
An order of priority for TIOA and/or TIOB events must be defined depending on the user
application.
41.12.6
TIMER_CLOCK2 not sampled on same edge as TIMER_CLOCK0 and TIMER_CLOCK1
TIMER_CLOCK2/TIMER_CLOCK5 is sampled on the system clock falling edge of Master Clock,
whereas TIMER_CLOCK0/TIMER_CLOCK3 and TIMER_CLOCK1/TIMER_CLOCK4 are sampled on the rising edge of Master Clock. This should not have any effect on the functional
operations of the Timer Counter unless the Timer Counter is used at its speed limit.
Problem Fix/Workaround
None.
41.12.7
Triggers do not clear the counter in Up/Down Mode
When the field WAVESEL in TC_CMR is at value 0x1 or 0x3, the triggers do not reset the counter value. The counter value can be reset only by modifying the field WAVESEL.
Problem Fix/Workaround
None.
41.12.8
Triggers in Up/Down Mode are lost when burst signal is active
When the field WAVESEL in TC_CMR is at value 0x1 or 0x3, the triggers occurring while the
selected burst signal is active (clock disabled) are not taken into account.
Problem Fix/Workaround
None.
41.12.9
Clock Selection Limitation in Up/Down Mode
Selecting the Master Clock or the Master Clock divided by 2 as the Timer Counter Clock may
lead to unpredictable result when the field WAVESEL in TC_CMR is at value 0x1 or 0x3.
Problem Fix/Workaround
680
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
None.
41.12.10 Spurious counter overflow in Up/Down Mode
When the field WAVESEL in TC_CMR is at value 0x1 or 0x3 and when the counter reaches the
value 0xFFFF, it inverts its sense and decrements to 0xFFFE. At the same time, the OVF bit in
TC_SR is set.
Problem Fix/Workaround
None.
41.13 TWI
41.13.1
Disabling Does not Operate Correctly
Any transfer in progress is immediately frozen if the Control Register (TWI_CR) is written with
the bit MSDIS at 1. Furthermore, the status bits TXCOMP and TXRDY in the Status Register
(TWI_SR) are not reset.
Problem Fix/Workaround
The user must wait for the end of transfer before disabling the TWI. In addition, the interrupts
must be disabled before disabling the TWI.
41.13.2
NACK Status Bit Lost
During a master frame, if TWI_SR is read between the Non Acknowledge condition detection
and the TXCOMP bit rising in the TWI_SR, the NACK bit is not set.
Problem Fix/Workaround
The user must wait for the TXCOMP status bit by interrupt and must not read the TWI_SR as
long as transmission is not completed.
Note:
41.13.3
TXCOMP and NACK fields are set simultaneously and the NACK field is reset after the read of the
TWI_SR.
Possible Receive Holding Register Corruption
When loading the TWI_RHR, the transfer direction is ignored. The last data byte received in the
TWI_RHR is corrupted at the end of the first subsequent transmit data byte. Neither RXRDY nor
OVERRUN status bits are set if this occurs.
Problem Fix/Workaround
The user must be sure that received data is read before transmitting any new data.
41.13.4
Clock Divider
The value of CLDIV x 2CKDIV must be less than or equal to 8191; the value of CHDIV x 2CKDIV
must be less than or equal to 8191.
Problem Fix/Workaround
None.
41.13.5
Software reset
When a software reset is performed during a frame and when TWCK is low, it is impossible to
initiate a new transfer in READ or WRITE mode.
681
1768I–ATARM–09-Jul-09
Problem Fix/Workaround
None.
41.13.6
TXCOMP and TXRDY reset
TXCOMP and TXRDY are not reset by MSDIS.
Problem Fix/Workaround
None.
41.13.7
Data lost on high latency
In case of high latency to process the RXRDY interrupt, with RXRDY set, if the receive data register is read at the same time as new data is captured into the register, the RXRDY flag is
cleared and the new data is lost because the associated RXRDY is not set.
Problem Fix/Workaround
None.
41.14 USART
41.14.1
RTS0 not connected
Internally, the RTS0 signal of the USART0 is not connected to PA21.
Problem Fix/Workaround
The RTS0 signal of the USART0 is connected to the PIO Controller D. The PIOD can be used to
control the RTS0 signal. The PIOD is only available in the AT91RM9200 BGA package.
41.14.2
US_IF must be initialized
US_IF must be initialized even in transmission mode.
Problem Fix/Workaround
None.
41.14.3
TXD signal is floating in Modem and Hardware Handshaking modes
The TXD signal should be pulled up in Modem and Hardware Handshaking modes.
Problem Fix/Workaround
TXD is multiplexed with PIO which integrates a pull-up resistor.
This internal pull-up needs to be enabled.
41.14.4
DCD is active High instead of Low
The DCD signal is active at 'High' level into the USART block (Modem mode).
DCD should be active at 'Low' level.
Problem Fix/Workaround
Add an inverter.
41.14.5
682
Bad value in Number of Errors Register
The Number of Errors Register always returns 0 instead of the ISO7816 error number.
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Problem/Fix Workaround
None.
41.15 USB Host Port
41.15.1
No pulldown on port 2 using 208-lead PQFP package
The second port of the UHP is unbonded and there is no pull-down on DP and DM.
This may result in an unexpected connect detection on the second port.
Problem Fix/Workaround
A software workaround is to hardcode the NDP field of the HcRhDescriptorA operational register
to 1.
683
1768I–ATARM–09-Jul-09
684
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
42. Revision History
Revision History
Version A
Publication Date: 22-Apr-03
Version B
Publication Date: 22-Aug-03
Page
Version B Changes Since Last Issue
Page 36
New Figure 8, ARM920T Internal Functional Block Diagram.
Page 56
Corrected fields in CP15 Register 7 register table.
Page 62
Updated Figure 9, AT91RM9200 Debug and Test Block Diagram with corrected DTXD and DRXD signal names and
transfer direction of signals TST0 - TST1 and NRST.
Page 85
Change signal name to NPCS0.
Page 86
Changes to Figure 15, Boot Program Algorithm Flow Diagram.
Page 87
Corrected BMS state to high during reset. Corrected address for internal ROM mapping.
Page 89
In Table 21 and text, corrected device names AT45DBxxx.
Page 91
Changes to Figure 20, Serial DataFlash Download.
Page 96
Updated Table 24 with new pins used and table note.
Page 108
Code change in section Description of the SvcXmodem Structure.
Page 109
Code change in Table 29: Xmodem Service, first table cell.
Page 110
Code change in section Using the Service.
Page 111
Code change in Table 30: DataFlash Service Methods, first table cell.
Page 116
Code change in Steps 1 and 2 in section Using the Service.
Page 233
Changed Table 58, I/O Line Description.
Page 245
In AIC Source Mode Register, corrected descriptions of bits PRIOR and SRCTYPE.
Page 255
Change number of programmable clocks to four. Correct oscillator speed to read 32.768 kHz.
Page 256
Updated section I/O Lines with new information on clocks.
Page 257
New PMC Block Diagram, Figure 117.
Page 258
Updated Processor Clock and Programmable Clock Outputs descriptions. Updated Clock Generator description.
Page 259
New Clock Generator Block Diagram, Figure 118. Section Slow Clock Oscillator Startup Time updated.
Page 261
Added section Main Oscillator Bypass.
Page 263
Updated section PLLB Divider by 2.
Page 264
In section Master Clock Controller, changed references to PLLB Output to PLLB Clock. New Figure 124: Master
Clock Controller. In section Processor Clock Source, specified differences between ARM7-based and ARM9-based
systems.
Page 265
Section Programmable Clock Output Controller updated to show change in number of programmable clocks.
Page 267
In Table 60: Clock Switching Timings (Worst Case), changed PLLA Output to PLLA Clock and PLLB Output to PLLB
Clock.
Page 268
In Figure 125: Switch Master Clock from Slow Clock to PLLA Clock and in Figure 126: Switch Master Clock from
Main Clock to Slow Clock, changed signal names and waveform labels.
Page 269
In Figure 127: Change PLLA Programming, changed signal names and labels. New Figure 128: Programmable
Clock Output Programming.
685
1768I–ATARM–09-Jul-09
Page
Version B Changes Since Last Issue (Continued)
Page 270
Changed register names in Table 61: PMC Register Mapping: PMC_MOR to CKGR_MOR, PMC_MCFR to
CKGR_MCFR, PMC_PLLAR to CKGR_PLLAR and PCM_PLLBR to CKGR_PLLBR. Remove registers
PMC_PCK4, PMC_PCK5, PMC_PCK6 and PMC_PCK7 (addresses 0x0050 to 0x005C).
Page 271
In register PMC_SCER, deleted bits PCK7 to PCK4, fields 15 to 12. All bit names updated to include “Enable”. In
UHP bit description, deleted reference to 12 MHz clock.
Page 272
In register PMC_SCDR, deleted bits PCK7 to PCK4, fields 15 to 12. All bit names updated to include “Disable”. In
UHP bit description, deleted reference to 12 MHz clock.
Page 273
In register PMC_SCSR, deleted bits PCK7 to PCK4, fields 15 to 12. All bit names updated to include “Status”. In
UHP bit description, corrected to read “USB Host Port”.
Page 276
Changed register name to PMC Clock Generator Main Oscillator Register. MOSCEN bit description changed to
include information on Main Clock signal and crystal connection. OSCOUNT bit description changed to remove
multiplication factor for Slow Clock cycles.
Page 277
Changed register name to PMC Clock Generator Main Clock Frequency Register. Corrected in MAINRDY field
description reference to MAINF.
Page 278
Changed register name to PMC Clock Generator PLL A Register. In OUTA and MULA bits, changed references to
PLLA Output to PLL A Clock.
Page 279
Changed register name to PMC Clock Generator PLL B Register. In OUTB and MULB bits, changed references to
PLLB Output to PLL B Clock. Changed bit description for USB_96M.
Page 280
In PMC_MCKR, new clock source selections specified for CSS. MDIV bit condition added.
Page 281
In PMC_PCK0 to PMC_PCK3, new clock source selections specified for CSS.
Page 282
In PMC_IER and PMC_IDR, bits PCK7RDY, PCK6RDY, PCK5RDY and PCK4RDY removed.
Page 283
In PMC_SR, bits PCK7RDY, PCK6RDY, PCK5RDY and PCK4RDY removed.
Page 284
In PMC_IMR, bits PCK7RDY, PCK6RDY, PCK5RDY and PCK4RDY removed.
Page 312
Added Note to Figure 135.
Page 331
In DBGU Chip ID Register, corrected NVPTYP field to 000 for ROM.
Page 343
In Table 67: PIO Register Mapping, PIO_OWSR access changed to read-only.
Page 358
In PIO_OWSR, access changed to read-only.
Page 368
Changed all references from CPHA to NCPHA. Updated Figures 159 and 160 for clarity.
Page 391
In CHDIV and CLDIV bit descriptions in register TWI_CWGR, corrected equations for calculation of SCL high and
low periods. In CHDIV, CLDIV and CKDIV bit descriptions in register TWI_CWGR, SCL replaced by TWCK.
Page 452
Updated Figure 214, Transmit Frame Format in Continuous Mode. Updated Figure 215, Receive Frame Format in
Continuous Mode.
Page 460
In register SSC_RFMR, new description of bit DATLEN.
Page 596
In Table 109, DC Characteristics, changed conditions for Static Current.
Page 598
New consumption figures in Table 113 and Table 114.
Page 599
In Table 115: 32 kHz Oscillator Characteristics, VDDOSC defined in Startup Time conditions. In Table 116: Main
Oscillator Characteristics, VDDPLL defined in Startup Time conditions. In Table 117: Phase Lock Loop
Characteristics, corrected errors in Pump current max/min values.
Page 601
In Table 120: Switching Characteristics in Full Speed, min/max values for Rise/Fall Time Matching added.
Page 614
In Table 125: SDRAMC Signals, changed min values for SDRAMC23 to SDRAMC28.
686
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Version C
Publication Date: 11-Feb-05
(Note: Page numbers listed below do not correspond to the page numbers as they appear in the revised datasheet format.)
Page
Version C Changes Since Last Issue
Global
All reference to Fast Forcing removed.
Global
Peripheral Data Controller (PDC) changed to Peripheral DMA Controller (PDC)
Global
SmartMedia. NAND Flash coupled to all references to SmartMedia, to read as; NAND Flash/SmartMedia.
Global
Input voltage range for VDDIOM and VDDIOP is 3.0. CSR 05-012
Page 1
Features: USART Hardware Handshaking. Reference to Software Handshaking removed. CSR 04-066
Page 3
Figure 1: NWAIT pin added to block diagram. CSR 03-209
Page 14
Table 1: AT91RM9200 Pinout for 208-lead PQFP package, pins 28, 30, 37 and 39 names modified. CSR 03244
Page 23
Table 7: Pin Description, ICE and JTAG description, “Internal Pullup” added to comments for all signals, except
TDO. CSR 04-315
Page 24
Table 7: Pin Description, NWAIT pin added. CSR 03-209
Page 68
Figure 14: AMP Mictor Connector Orientation, correct illustration inserted. CSR 03-242
Page 89
Table 21: DataFlash Device, AT45DB2562 removed. CSR 03-221
Page 91
Figure 20: Serial DataFlash Download, Correct illustration inserted. CSR 04-404
Page 127
Internal Memory Area 0 and Table 35: 16-bit value given to Memory Area 0.
Page 137
Boot Mode Select: 16-bit value given to external boot memory. CSR 03-205
Page 139
Table 37: I/O Lines Description NWAIT signal relocated to SMC. CSR 03-209
Page 150
Table 39: EBI Pins and External Device Connections, Pin/Controller line A13 - A15 changed to A13-A14 and
SDRAMC changed to A11- A12. Pin/Controller line A15 added. CSR 03-217
Page 191
SMC Chip Select Registers; figures cross-referenced to RWHOLD signal.
Page 226
EBI_CFGR Register: Warning added to bit #1. CSR 03-243
Page 245
Table 57: Register Mapping. PERIPH_PTSR offset changed to 0x124. CSR 04-188
Page 259
SRCTYPE Interrupt source type descriptions changed.
Page 260
Figure 119. Typical Slow Clock Oscillator Connection; GNDPLL changed to GNDOSC.
Page 261
Figure 121. Typical Crystal Connection; GNDPLL changed to GNDOSC.
Page 261
Main Oscillator Control: sentence corrected to read; “....counting down on Slow Clock from the OSCOUNT
value. CSR 03-232
Page 278
Main Oscillator Bypass: XIN pin information changed. CSR 04-405
Page 279
PMC Clock Generator PLL A Register; Line added to CKGR_PLLA limitations. CSR 05-005
Page 279
PMC Clock Generator PLL B Register; Line added to CKGR_PLLB limitations. CSR 05-005
Page 289
Table 62: Register Mapping. ST_IMR Register is read-only. CSR 03-232
Page 295
Real Time Controller changed to Real Time Clock. CSR 04-020
Page 311(GLobal)
Debug Unit (DBGU), ICE Access Prevention removed.
Page 320, 332
Debut Unit User Interface: Force NTRST Register removed.
Page 348
PIO. Pull-up Resistor Control. Value of resistor changed from approximately 100 kΩ to 10 kΩ.
Page 351 (Global)
PIO. Change PIO_PDSR from Peripheral Data Status Register to Pin Data Status Register
687
1768I–ATARM–09-Jul-09
Page
Version C Changes Since Last Issue (Continued)
Page 362
Master Mode Operations: Cross reference to SPI User interface clarified. CSR 04-406
Page 368
Table 69: SPI Bus Protocol Mode, NCPHA column corrected. CSR 04-239
Page 386
Figure 170. TWI Write in Master Mode. “Set the control register”; reference to slave removed.
Page 387
Figure 171. TWI Read in Master Mode. Set the control register”; reference to slave removed.
Page 399
Changes to definitions of abbreviations in TWI “Transmitting Data” figure drawings.
Page 404
TWI Master Mode Register. IADRSZ[9:8], change to first line.
Page 405
TWI Internal Address Register. Text added to IADR description.
Page 406
TWI Status Register. Change to TXCOMP bit. Reference to slave removed.
Page 408
Multi-drop Mode: PAR field setting changed. CSR 04-187
Page 415
Receive NACK Inhibit: “Moreover, if INACK is reset”......(replaces; if INACK is set) CSR 05-006
Page 419
RS485 Mode and Figure 196. Typical Connection to an RS485 bus; changed RTS signal information. CSR 03190
Page 502
Table 94. Bus Topology; footnote added to Type column of Pin Number “2” row.
Page 503
Command/Response Operation: PWSEN bit power saving formula changed...dividing the MCI clock by
[(2PWSDIV)+1].
Page 512
MCI_MR: PSWSDIV bit power saving formula changed... MCI clock divided by [(2PWSDIV)+1] when entering
Power Saving Mode. CSR 05-009
Page 523
UDP: Overview, text changed.
Page 525
Main features of UDP changed. CSR 04-026
Page 526
Figure 244. Board Schematic to Interface USB Device Peripheral. USB signals added to figure.
Page 528
Figure 244: Resistor level changed. CSR 04-025, CSR 04-116
Page 544 &560
UDP User Interface: Transceiver Control Register (USB_TXVC) added.
Page 567
Power Management: Steps to put EMAC in Local Loopback Mode added. CSR 05-014
Page 594
Table 109: VDDIOM and VDDIOP DC Supply Characteristics, Max changed to 3.6.
CSR 04-076
VDDIOM and VDDIOP DC Supply Characteristics, Min changed to 3.0
ISC Condition changed to On VDDcore = 1.95V
Page 596
Power Consumption: added; • EMAC 50MHz clock not connected
Table 113: Power Consumption for PMC Modes, and Table 114: Power Consumption by Peripheral,
Consumption values changed. CSR 03-234
Table 114: Power Consumption by Peripheral. Note added to EMAC line
Page 597
Table 117: Phase Lock Loop Characteristics, changes to “FOUT” line. The “K0“ and “IP” lines have been
eliminated. CSR 04-234, CSR 04-006
Page 604 - 605
Temperature Derating Factor: Figures 266, 267 and 268; derating curves changed. CSR 05-013
Page 626-629
Package Drawings: Tables 136 - 141 added, figure 278; 256-ball BGA package drawing changed.
Page 630-631
Soldering Profiles: Tables 142 - 143 added for Standard package and table 144 for Green and RoHScompliant package.
Page 633
Table 145; Ordering Information. New information added.
688
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Version D
Publication Date: 11-Jul-05
Page
Change
CSR Ref.
25
In Table 4-7, “Pin Description List,” on page 25 added mention of Schmitt trigger for pins JTAGSEL,
TDI, TCK, TMS, NTRST, TST0, TST1 AND NRST.
05-348
140
Changed use of NWR1 for 8-bit static device in Table 17-3, “EBI Pins and External Device
Connections” from WE to “-”.
-
217
218
Removed Flash device references in Figure 20-2 in “Burst Flash Controller (BFC)” .
Removed Section 20.5.1 “I/O Lines” on page 218.
05-122
342
In “SRAMSIZ: Internal SRAM Size” bit description in “Debug Unit (DBGU)” , changed Size from
“Reserved” to “80K bytes”.
05-115
348
New information on value of internal pull-ups in “Pull-up Resistor Control” , Section 21.4.1.
05-352
422
Corrected information on parity levels in “Universal Synchronous Asynchronous Receiver
Transceiver (USART)” , Section 30.6.3.5.
Corrected stop bit level in Figure 30-15.
Made all reset values hexadecimal in Table 30-12 on page 437.
05-067
05-147
05-148
586
In “USB Device Port (UDP)” , changed all register names to UDP_xxx.
Replaced ENDBURST by ENDBUSRES in “USB Device Port (UDP)” , Section 34.5.3.1 and “UDP
Interrupt Clear Register” .
Updated “ENDBUSRES: Clear End of Bus Reset Interrupt” bit description,
596
Added information on memory access errors in “USB Host Port (UHP)” , Section 35.2.
05-240
632
In Table 37-2, changed min and max values for IPULL and added new information on RPULLUP.
05-352
633
Changed references from Master Clock to Processor Clock in Table 37-3, “Processor Clock
Waveform Parameters,” on page 633.
05-123
642 and
following
In “AT91RM9200 AC Characteristics” , updated derating figures in Table 38-1, Table 38-2,
Table 38-5, Table 38-7, Table 38-8 and Table 38-11.
05-287
669
Updated ordering reference for PQFP208 Green package option in Table 40-1.
427
437
All
570
05-181
689
1768I–ATARM–09-Jul-09
Revision History (cont.)
Document Version
1768E
Change
CSR Ref.
In ”Features” on page 1, corrected power consumption values.
05-371
In Section 23.6.7 “PMC Clock Generator Main Oscillator Register” on page 283, removed
all references to OSCBYPASS.
05-450
In Table 36-5, “EMAC Register Mapping,” on page 612, update Statistics Registers with
offset correction and new registers. In Table 36-6, “EMAC Statistic Register Block Register
Descriptions,” on page 629, update with new offset corrections and registers.
05-435
Removed MTBF data from Section 39.1.1 “Thermal Data” on page 661.
05-453
Included new Section 41. “AT91RM9200 Errata” on page 671 in datasheet. Formerly
document 6015G.
Reformatted Section 8. “Memories” on page 17. Inserted new figure Figure 8-1 on page 17
with overall product memory map.
Removed note in Table 17-3, “EBI Pins and External Device Connections,” on page 137
giving information on ALE and CLE pins.
1730
Added Section 17.7 “Implementation Examples” on page 147 with figures,
1768F
Removed Application Example from “Static Memory Controller (SMC)” .
Removed Application Example from “SDRAM Controller (SDRAMC)” .
2663
Revised and updated Section 33. “MultiMedia Card Interface (MCI)” on page 519.
2664
Corrected errata: Updated Static Current Typ and Max values in Table 37-2, “DC
Characteristics,” on page 632; updated max PLL output frequency in Table 37-10, “Phase
Lock Loop Characteristics,” on page 636.
Renumbered and updated Section 41. “AT91RM9200 Errata” on page 671.
2516, 2517,
2525, 2608
Changed values in Table 39-12, “Soldering Profile,” on page 666.
2492
Updated “Features” and Section 4. “Package and Pinout” on page 8 with additional details
on package options.
1768G
PMC: Updated capacitor details in Section 23.4.5.1 “Main Oscillator Connections” on page
266 and Section 23.4.5.5 “Main Oscillator Bypass” on page 267.
3339
UDP: In Section 34.6.4 “UDP Interrupt Enable Register” on page 576, Section 34.6.5
“UDP Interrupt Disable Register” on page 578, Section 34.6.6 “UDP Interrupt Mask
Register” on page 580, Section 34.6.7 “UDP Interrupt Status Register” on page 582 and
Section 34.6.9 “UDP Reset Endpoint Register” on page 587, removed all references to
Endpoint 6 and Endpoint 7 (bits and bit descriptions).
3203
Updated Table 37-1, “Absolute Maximum Ratings*,” on page 631.
3063
Updated Input Capacitance value in Table 37-7, “XIN Clock Electrical Characteristics,” on
page 634.
3339
Updated CL, CL1, CL2 values in Table 37-6, “Main Oscillator Characteristics,” on page 634.
3287, 3339
Updated Table 40-1, “Ordering Information,” on page 669.
In “AT91RM9200 Errata” , added Section 41.1 “Marking” on page 671.
1768H
690
Ordering code AT91RM9200-CI-002 removed from Section 40. “AT91RM9200 Ordering
Information” on page 669
6423
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Document Version
1768I
Change
CSR Ref.
USB Endpoint Size values edited in Table 34-1 on page 557
3481
A Warning paragraph added to Section 34.6.10 “UDP Endpoint Control and Status
Register” on page 588
3764
LDR Opcode edited in Figure 13-3 on page 86
4453
Sections 37.4 and 37.5 reversed, to have “Clock Characteristics” followed by “Crystal
Oscillator Characteristics”
4666
Section 41.14.3 “TXD signal is floating in Modem and Hardware Handshaking modes” on
page 682 and Section 41.14.4 “DCD is active High instead of Low” on page 682 added to
USART Errata
4723
240 MHz value changed into 180 MHz in Section 23.4.3 “Clock Generator” on page 264
4923
240 MHz value in OUTA and OUTB tables changed into 180 MHz in Section 23.6.9 “PMC
Clock Generator PLL A Register” on page 285 and Section 23.6.10 “PMC Clock Generator
PLL B Register” on page 286
4925
Section 41.6.4 “OSCBYPASS is not functional with PLLA” on page 675 added to PMC
Errata
4964
USART3 0XFFECC000 changed into 0XFFFCC000 in Figure 8-1 on page 17
5067
OSCBYPASS added, MOSCEN and OSCOUNT edited in Section 23.6.7 “PMC Clock
Generator Main Oscillator Register” on page 283
5077
2 rows added to Table 38-4 on page 649
5102
Section 25.4.5 “Updating Time/Calendar” on page 307 edited
5113
Standby conditions edited in Table 37-8 on page 635
5192
A footnote added to USART “Overview” on page 411
5208
Weight values changed in Table 39-4 on page 663 and Table 39-7 on page 664
5258
2CKDIV changed into 2CKDIV in Section 41.13.4 “Clock Divider” on page 681
5431
Section 18. “Static Memory Controller (SMC)” on page 155 changed, using SMC_ABC
(6153) Programmer Datasheet content
5618
SDIO, SDIORQA and SDIORQB removed from Section 33.9 “MultiMedia Card Interface
(MCI) User Interface” on page 533
5628
NWDOVF removed from Figure 24-1 on page 293 and Figure 24-4 on page 295.
Section 24.4.3 Watchdog Overflow removed.
EXTEN removed from Figure 24-4 on page 295, from Section 24.5.3 “Watchdog Timer
(WDT)” on page 295, and from Section 24.6.3 “ST Watchdog Mode Register” on page 298
5683
Main Oscillator Table 37-6 on page 634 edited, and 4 values (Driver Level, ESR, Shunt
and Motionless Capacitance) added
6333
MCI erratum added: Section 41.4.11 “Data write operation and number of bytes” on page
674
6426
- XIN Clock moved from “Clock Characteristics” to “Crystal Oscillator Characteristics” .
- SSC erratum added: Section 41.11.7 “Unexpected delay on TD output” on page 679
- USART erratum added: Section 41.14.5 “Bad value in Number of Errors Register” on
page 682.
RFO
691
1768I–ATARM–09-Jul-09
692
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
Table of Contents
Features ..................................................................................................... 1
1
Description ............................................................................................... 2
2
Block Diagram .......................................................................................... 3
3
Signal Description ................................................................................... 4
4
Package and Pinout ................................................................................. 8
4.1208-pin PQFP Package Outline ................................................................................8
4.2208-pin PQFP Package Pinout .................................................................................9
4.3256-ball BGA Package Outline ................................................................................10
4.4256-ball BGA Package Pinout .................................................................................11
5
Power Considerations ........................................................................... 13
5.1Power Supplies .......................................................................................................13
5.2Power Consumption ................................................................................................13
6
I/O Considerations ................................................................................. 13
6.1JTAG Port Pins ........................................................................................................13
6.2Test Pin ...................................................................................................................13
6.3Reset Pin .................................................................................................................13
6.4PIO Controller A, B, C and D Lines .........................................................................14
7
Processor and Architecture .................................................................. 14
7.1ARM920T Processor ...............................................................................................14
7.2Debug and Test .......................................................................................................14
7.3Boot Program ..........................................................................................................15
7.4Embedded Software Services .................................................................................15
7.5Memory Controller ...................................................................................................15
8
Memories ................................................................................................ 17
8.1Embedded Memories ..............................................................................................18
9
System Peripherals ................................................................................ 19
9.1Reset Controller ......................................................................................................19
9.2Advanced Interrupt Controller .................................................................................19
9.3Power Management Controller ................................................................................19
9.4Debug Unit ..............................................................................................................20
9.5PIO Controller ..........................................................................................................20
i
1768I–ATARM–09-Jul-09
10 User Peripherals .................................................................................... 21
10.1User Interface ........................................................................................................21
10.2Peripheral Identifiers .............................................................................................21
10.3Peripheral Multiplexing on PIO Lines ....................................................................22
10.4External Bus Interface ...........................................................................................27
10.5Static Memory Controller .......................................................................................27
10.6SDRAM Controller .................................................................................................28
10.7Burst Flash Controller ............................................................................................28
10.8Peripheral DMA Controller (PDC) ..........................................................................29
10.9System Timer ........................................................................................................29
10.10Real-time Clock ...................................................................................................29
10.11USB Host Port .....................................................................................................29
10.12USB Device Port .................................................................................................29
10.13Ethernet MAC ......................................................................................................29
10.14Serial Peripheral Interface ...................................................................................30
10.15Two-wire Interface ...............................................................................................30
10.16USART ................................................................................................................30
10.17Serial Synchronous Controller .............................................................................31
10.18Timer Counter .....................................................................................................31
10.19MultiMedia Card Interface ...................................................................................32
11 ARM920T Processor Overview ............................................................. 33
11.1Overview ...............................................................................................................33
11.2Block Diagram .......................................................................................................35
11.3ARM9TDMI Processor ..........................................................................................36
11.4CP15 Coprocessor ................................................................................................41
11.5Memory Management Unit (MMU) ........................................................................43
11.6Caches, Write Buffers and Physical Address ........................................................44
11.7ARM920T User Interface .......................................................................................46
12 Debug and Test Features (DBG Test) .................................................. 59
12.1Overview ...............................................................................................................59
12.2Block Diagram .......................................................................................................60
12.3Application Examples ............................................................................................61
12.4Test Environment ..................................................................................................61
12.5Debug and Test Pin Description ............................................................................62
12.6Functional Description ...........................................................................................63
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1768I–ATARM–09-Jul-09
AT91RM9200
13 Boot Program ......................................................................................... 83
13.1Overview ..............................................................................................................83
13.2Flow Diagram ........................................................................................................84
13.3Bootloader .............................................................................................................85
13.4Boot Uploader .......................................................................................................92
13.5Hardware and Software Constraints .....................................................................94
14 Embedded Software Services ............................................................... 95
14.1Overview ...............................................................................................................95
14.2Service Definition ..................................................................................................95
14.3Embedded Software Services ...............................................................................99
15 AT91RM9200 Reset Controller ............................................................ 117
15.1Overview .............................................................................................................117
16 Memory Controller (MC) ...................................................................... 121
16.1Overview .............................................................................................................121
16.2Block Diagram .....................................................................................................122
16.3Functional Description .........................................................................................123
16.4User Interface ......................................................................................................128
17 External Bus Interface (EBI) ................................................................ 133
17.1Overview .............................................................................................................133
17.2Block Diagram .....................................................................................................134
17.3I/O Lines Description ...........................................................................................135
17.4Application Example ............................................................................................137
17.5Product Dependencies ........................................................................................140
17.6Functional Description .........................................................................................140
17.7Implementation Examples ...................................................................................147
17.8External Bus Interface (EBI) User Interface ........................................................151
18 Static Memory Controller (SMC) ......................................................... 155
18.1Overview .............................................................................................................155
18.2Block Diagram .....................................................................................................156
18.3I/O Lines Description ...........................................................................................157
18.4Product Dependencies ........................................................................................158
18.5Functional Description .........................................................................................158
18.6Static Memory Controller (SMC) User Interface ..................................................190
19 SDRAM Controller (SDRAMC) ............................................................ 195
iii
1768I–ATARM–09-Jul-09
19.1Overview .............................................................................................................195
19.2Block Diagram .....................................................................................................196
19.3I/O Lines Description ...........................................................................................196
19.4Software Interface ...............................................................................................197
19.5Product Dependencies ........................................................................................199
19.6Functional Description .........................................................................................201
19.7SDRAM Controller (SDRAMC) User Interface ....................................................207
20 Burst Flash Controller (BFC) .............................................................. 217
20.1Overview .............................................................................................................217
20.2Block Diagram .....................................................................................................218
20.3I/O Lines Description ...........................................................................................218
20.4Application Example ............................................................................................219
20.5Product Dependencies ........................................................................................220
20.6Functional Description .........................................................................................220
20.7Burst Flash Controller (BFC) User Interface ........................................................229
21 Peripheral DMA Controller (PDC) ....................................................... 231
21.1Overview .............................................................................................................231
21.2Block Diagram .....................................................................................................231
21.3Functional Description .........................................................................................232
21.4Peripheral DMA Controller (PDC) User Interface ...............................................234
22 Advanced Interrupt Controller (AIC) .................................................. 241
22.1Overview .............................................................................................................241
22.2Block Diagram .....................................................................................................242
22.3Application Block Diagram ..................................................................................242
22.4AIC Detailed Block Diagram ................................................................................242
22.5I/O Line Description .............................................................................................243
22.6Product Dependencies ........................................................................................243
22.7Functional Description .........................................................................................244
22.8Advanced Interrupt Controller (AIC) User Interface .............................................253
23 Power Management Controller (PMC) ................................................ 263
23.1Overview .............................................................................................................263
23.2Product Dependencies ........................................................................................264
23.3Block Diagram .....................................................................................................265
23.4Functional Description .........................................................................................266
23.5Clock Switching Details .......................................................................................275
iv
AT91RM9200
1768I–ATARM–09-Jul-09
AT91RM9200
23.6Power Management Controller (PMC) User Interface ........................................278
24 System Timer (ST) ............................................................................... 295
24.1Overview .............................................................................................................295
24.2Block Diagram .....................................................................................................295
24.3Application Block Diagram ..................................................................................296
24.4Product Dependencies ........................................................................................296
24.5Functional Description .........................................................................................296
24.6System Timer (ST) User Interface .......................................................................298
25 Real Time Clock (RTC) ........................................................................ 307
25.1Overview .............................................................................................................307
25.2Block Diagram .....................................................................................................307
25.3Product Dependencies ........................................................................................307
25.4Functional Description .........................................................................................308
25.5Real Time Clock (RTC) User Interface ................................................................310
26 Debug Unit (DBGU) .............................................................................. 323
26.1Overview .............................................................................................................323
26.2Block Diagram .....................................................................................................324
26.3Product Dependencies ........................................................................................325
26.4UART Operations ................................................................................................325
26.5Debug Unit User Interface ..................................................................................332
27 Parallel Input/Output Controller (PIO) ................................................ 347
27.1Overview .............................................................................................................347
27.2Block Diagram .....................................................................................................348
27.3Product Dependencies ........................................................................................349
27.4Functional Description .........................................................................................349
27.5I/O Lines Programming Example ........................................................................354
27.6Parallel Input/Output Controller (PIO) User Interface ..........................................356
28 Serial Peripheral Interface (SPI) ......................................................... 373
28.1Overview .............................................................................................................373
28.2Block Diagram .....................................................................................................374
28.3Application Block Diagram ..................................................................................375
28.4Product Dependencies ........................................................................................376
28.5Functional Description .........................................................................................376
28.6Serial Peripheral Interface (SPI) User Interface ..................................................384
v
1768I–ATARM–09-Jul-09
29 Two-wire Interface (TWI) ...................................................................... 397
29.1Overview .............................................................................................................397
29.2Block Diagram .....................................................................................................397
29.3Application Block Diagram ..................................................................................397
29.4Product Dependencies ........................................................................................398
29.5Functional Description .........................................................................................398
29.6Two-wire Interface (TWI) User Interface ............................................................404
30 Universal Synchronous Asynchronous Receiver Transceiver
(USART) ................................................................................................ 413
30.1Overview .............................................................................................................413
30.2Block Diagram .....................................................................................................414
30.3Application Block Diagram ..................................................................................415
30.4I/O Lines Description ..........................................................................................415
30.5Product Dependencies ........................................................................................415
30.6Functional Description .........................................................................................416
30.7USART User Interface ........................................................................................439
31 Serial Synchronous Controller (SSC) ................................................ 457
31.1Overview .............................................................................................................457
31.2Block Diagram .....................................................................................................458
31.3Application Block Diagram ..................................................................................458
31.4Pin Name List ......................................................................................................459
31.5Product Dependencies ........................................................................................459
31.6Functional Description .........................................................................................459
31.7SSC Application Examples ..................................................................................468
31.8Serial Synchronous Controller (SSC) User Interface ..........................................471
32 Timer Counter (TC) .............................................................................. 487
32.1Overview .............................................................................................................487
32.2Block Diagram .....................................................................................................488
32.3Pin Name List ......................................................................................................489
32.4Product Dependencies ........................................................................................489
32.5Functional Description .........................................................................................489
32.6Waveform Operating Mode .................................................................................494
32.7Timer Counter (TC) User Interface ......................................................................502
33 MultiMedia Card Interface (MCI) ......................................................... 521
33.1Description ..........................................................................................................521
vi
AT91RM9200
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AT91RM9200
33.2Block Diagram .....................................................................................................522
33.3Application Block Diagram ..................................................................................523
33.4Pin Name List .....................................................................................................523
33.5Product Dependencies ........................................................................................524
33.6Bus Topology ......................................................................................................524
33.7MultiMedia Card Operations ................................................................................527
33.8SD Card Operations ............................................................................................534
33.9MultiMedia Card Interface (MCI) User Interface ..................................................535
34 USB Device Port (UDP) ........................................................................ 555
34.1Overview .............................................................................................................555
34.2Block Diagram .....................................................................................................556
34.3Product Dependencies ........................................................................................557
34.4Typical Connection ..............................................................................................558
34.5Functional Description .........................................................................................559
34.6USB Device Port (UDP) User Interface ...............................................................574
35 USB Host Port (UHP) ........................................................................... 595
35.1Overview .............................................................................................................595
35.2Block Diagram .....................................................................................................596
35.3Product Dependencies ........................................................................................597
35.4Functional Description .........................................................................................598
35.5Typical Connection ..............................................................................................600
36 Ethernet MAC (EMAC) ......................................................................... 601
36.1Overview .............................................................................................................601
36.2Block Diagram .....................................................................................................602
36.3Application Block Diagram ..................................................................................602
36.4Product Dependencies ........................................................................................603
36.5Functional Description .........................................................................................604
36.6Ethernet MAC (EMAC) User Interface ................................................................612
37 AT91RM9200 Electrical Characteristics ............................................. 631
37.1Absolute Maximum Ratings .................................................................................631
37.2DC Characteristics ..............................................................................................632
37.3Clocks Characteristics .........................................................................................633
37.4Power Consumption ............................................................................................634
37.5Crystal Oscillators Characteristics .......................................................................635
37.6PLL Characteristics .............................................................................................635
vii
1768I–ATARM–09-Jul-09
37.7Transceiver Characteristics .................................................................................636
38 AT91RM9200 AC Characteristics ....................................................... 639
38.1Applicable Conditions and Derating Data ............................................................639
38.2EBI Timings .........................................................................................................642
38.3JTAG/ICE Timings ...............................................................................................657
38.4ETM Timings .......................................................................................................660
39 AT91RM9200 Mechanical Characteristics ......................................... 661
39.1Thermal and Reliability Considerations ...............................................................661
39.2Package Drawings ..............................................................................................662
39.3Soldering Profiles ................................................................................................665
40 AT91RM9200 Ordering Information .................................................... 669
41 AT91RM9200 Errata ............................................................................. 671
41.1Marking ................................................................................................................671
41.2EBI .......................................................................................................................672
41.3EMAC ..................................................................................................................672
41.4MCI ......................................................................................................................672
41.5PIO ......................................................................................................................674
41.6PMC ....................................................................................................................674
41.7ROM Bootloader ..................................................................................................675
41.8SDRAMC .............................................................................................................675
41.9SMC ....................................................................................................................676
41.10SPI .....................................................................................................................676
41.11SSC ...................................................................................................................677
41.12TC ......................................................................................................................678
41.13TWI ....................................................................................................................680
41.14USART ..............................................................................................................681
41.15USB Host Port ...................................................................................................681
42 Revision History ................................................................................... 683
Revision History (cont.)........................................................................ 688
Table of Contents....................................................................................... i
viii
AT91RM9200
1768I–ATARM–09-Jul-09
Headquarters
International
Atmel Corporation
2325 Orchard Parkway
San Jose, CA 95131
USA
Tel: 1(408) 441-0311
Fax: 1(408) 487-2600
Atmel Asia
Unit 1-5 & 16, 19/F
BEA Tower, Millennium City 5
418 Kwun Tong Road
Kwun Tong, Kowloon
Hong Kong
Tel: (852) 2245-6100
Fax: (852) 2722-1369
Atmel Europe
Le Krebs
8, Rue Jean-Pierre Timbaud
BP 309
78054 Saint-Quentin-enYvelines Cedex
France
Tel: (33) 1-30-60-70-00
Fax: (33) 1-30-60-71-11
Atmel Japan
9F, Tonetsu Shinkawa Bldg.
1-24-8 Shinkawa
Chuo-ku, Tokyo 104-0033
Japan
Tel: (81) 3-3523-3551
Fax: (81) 3-3523-7581
Technical Support
AT91SAM Support
Atmel techincal support
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1768I–ATARM–09-Jul-09