ATMEL AT91SAM9263-CU Thumb microcontroller Datasheet

Features
• Incorporates the ARM926EJ-S™ ARM® Thumb® Processor
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– DSP Instruction Extensions, Jazelle® Technology for Java® Acceleration
– 16 Kbyte Data Cache, 16 Kbyte Instruction Cache, Write Buffer
– 220 MIPS at 200 MHz
– Memory Management Unit
– EmbeddedICE™, Debug Communication Channel Support
– Mid-level Implementation Embedded Trace Macrocell™
Bus Matrix
– Nine 32-bit-layer Matrix, Allowing a Total of 28.8 Gbps of On-chip Bus Bandwidth
– Boot Mode Select Option, Remap Command
Embedded Memories
– One 128 Kbyte Internal ROM, Single-cycle Access at Maximum Bus Matrix Speed
– One 80 Kbyte Internal SRAM, Single-cycle Access at Maximum Processor or Bus
Matrix Speed
– One 16 Kbyte Internal SRAM, Single-cycle Access at Maximum Bus Matrix Speed
Dual External Bus Interface (EBI0 and EBI1)
– EBI0 Supports SDRAM, Static Memory, ECC-enabled NAND Flash and
CompactFlash®
– EBI1 Supports SDRAM, Static Memory and ECC-enabled NAND Flash
DMA Controller (DMAC)
– Acts as one Bus Matrix Master
– Embeds 2 Unidirectional Channels with Programmable Priority, Address
Generation, Channel Buffering and Control
Twenty Peripheral DMA Controller Channels (PDC)
LCD Controller
– Supports Passive or Active Displays
– Up to 24 bits per Pixel in TFT Mode, Up to 16 bits per Pixel in STN Color Mode
– Up to 16M Colors in TFT Mode, Resolution Up to 2048x2048, Supports Virtual
Screen Buffers
2D Graphics Accelerator
– Line Draw, Block Transfer, Polygon Fill, Clipping, Commands Queuing
Image Sensor Interface
– ITU-R BT. 601/656 External Interface, Programmable Frame Capture Rate
– 12-bit Data Interface for Support of High Sensibility Sensors
– SAV and EAV Synchronization, Preview Path with Scaler, YCbCr Format
USB 2.0 Full Speed (12 Mbits per second) Host Double Port
– Dual On-chip Transceivers
– Integrated FIFOs and Dedicated DMA Channels
USB 2.0 Full Speed (12 Mbits per second) Device Port
– On-chip Transceiver, 2,432-byte Configurable Integrated DPRAM
Ethernet MAC 10/100 Base-T
– Media Independent Interface or Reduced Media Independent Interface
– 28-byte FIFOs and Dedicated DMA Channels for Receive and Transmit
Fully-featured System Controller, including
– Reset Controller, Shutdown Controller
– Twenty 32-bit Battery Backup Registers for a Total of 80 Bytes
– Clock Generator and Power Management Controller
– Advanced Interrupt Controller and Debug Unit
AT91 ARM
Thumb
Microcontrollers
AT91SAM9263
Preliminary
6249B–ATARM–14-Dec-06
– Periodic Interval Timer, Watchdog Timer and Double Real-time Timer
• Reset Controller (RSTC)
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2
– Based on Two Power-on Reset Cells, Reset Source Identification and Reset Output Control
Shutdown Controller (SHDWC)
– Programmable Shutdown Pin Control and Wake-up Circuitry
Clock Generator (CKGR)
– 32768Hz Low-power Oscillator on Battery Backup Power Supply, Providing a Permanent Slow Clock
– 3 to 20 MHz On-chip Oscillator and Two Up to 240 MHz PLLs
Power Management Controller (PMC)
– Very Slow Clock Operating Mode, Software Programmable Power Optimization Capabilities
– Four Programmable External Clock Signals
Advanced Interrupt Controller (AIC)
– Individually Maskable, Eight-level Priority, Vectored Interrupt Sources
– Two External Interrupt Sources and One Fast Interrupt Source, Spurious Interrupt Protected
Debug Unit (DBGU)
– 2-wire UART and Support for Debug Communication Channel, Programmable ICE Access Prevention
Periodic Interval Timer (PIT)
– 20-bit Interval Timer plus 12-bit Interval Counter
Watchdog Timer (WDT)
– Key-protected, Programmable Only Once, Windowed 16-bit Counter Running at Slow Clock
Two Real-time Timers (RTT)
– 32-bit Free-running Backup Counter Running at Slow Clock with 16-bit Prescaler
Five 32-bit Parallel Input/Output Controllers (PIOA, PIOB, PIOC, PIOD and PIOE)
– 160 Programmable I/O Lines Multiplexed with Up to Two Peripheral I/Os
– Input Change Interrupt Capability on Each I/O Line
– Individually Programmable Open-drain, Pull-up Resistor and Synchronous Output
One Part 2.0A and Part 2.0B-compliant CAN Controller
– 16 Fully-programmable Message Object Mailboxes, 16-bit Time Stamp Counter
Two Multimedia Card Interface (MCI)
– SDCard/SDIO and MultiMediaCard™ Compliant
– Automatic Protocol Control and Fast Automatic Data Transfers with PDC
– Two SDCard Slots Support on eAch Controller
Two 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
One AC97 Controller (AC97C)
– 6-channel Single AC97 Analog Front End Interface, Slot Assigner
Three Universal Synchronous/Asynchronous Receiver Transmitters (USART)
– Individual Baud Rate Generator, IrDA® Infrared Modulation/Demodulation, Manchester Encoding/Decoding
– Support for ISO7816 T0/T1 Smart Card, Hardware Handshaking, RS485 Support
Two Master/Slave Serial Peripheral Interface (SPI)
– 8- to 16-bit Programmable Data Length, Four External Peripheral Chip Selects
– Synchronous Communications at Up to 90Mbits/sec
One Three-channel 16-bit Timer/Counters (TC)
– Three External Clock Inputs, Two Multi-purpose I/O Pins per Channel
– Double PWM Generation, Capture/Waveform Mode, Up/Down Capability
One Four-channel 16-bit PWM Controller (PWMC)
One Two-wire Interface (TWI)
– Master Mode Support, All Two-wire Atmel® EEPROMs Supported
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
• IEEE® 1149.1 JTAG Boundary Scan on All Digital Pins
• Required Power Supplies
– 1.08V to 1.32V for VDDCORE and VDDBU
– 3.0V to 3.6V for VDDOSC and VDDPLL
– 2.7V to 3.6V for VDDIOP0 (Peripheral I/Os)
– 1.65V to 3.6V for VDDIOP1 (Peripheral I/Os)
– Programmable 1.65V to 1.95V or 3.0V to 3.6V for VDDIOM0/VDDIOM1 (Memory I/Os)
• Available in a 324-ball BGA Green Package
1. Description
The AT91SAM9263 32-bit microcontroller, based on the ARM926-EJ-S processor, is architectured on a 9-layer matrix, allowing a maximum internal bandwidth of nine 32-bit buses. It also
features two independent external memory buses, EBI0 and EBI1, capable of interfacing with a
wide range of memory devices and an IDE hard disk. Two external buses prevent bottlenecks,
thus guaranteeing maximum performance.
The AT91SAM9263 embeds an LCD Controller supported by a 2D Graphics Controller and a 2channel DMA Controller, and one Image Sensor Interface. It also integrates several standard
peripherals, such as USART, SPI, TWI, Timer Counters, PWM Generators, Multimedia Card
interface and one CAN Controller.
When coupled with an external GPS engine, the AT91SAM9263 provides the ideal solution for
navigation systems.
3
6249B–ATARM–14-Dec-06
In-Circuit
Emulator
PDC
PLLA
PLLRCB
PLLB
XIN
XOUT
ETM
ICache
16K bytes
TCM Interface
PMC
ITCM
MMU
DCache
16K bytes
LUT
Bus Interface
DTCM
I
OSC
LCD
Controller
ARM926EJ-S Processor
DBGU
PLLRCA
Transc. Transc.
EBI0
AIC
DRXD
DTXD
PCK0-PCK3
EBI0_
JTAG Boundary Scan
System
Controller
FIQ
IRQ0-IRQ1
TC
TS LK
TPYN
C
TPS0
K -TP
BM 0-T S2
S PK1
5
LC
LCDD
0
LCDV -LC
S
LCDH YN DD
S
LCDD YNC 23
O
LCDD TCC
E
D N K
C
ET C
ETXCK
ECXEN-ER
R - X
ER S- ETX CK
E
ERXE CO ER ERE
R L
FC
ET X0- -ER
K
X E X
EM 0-E RX DV
3
EMDC TX
3
EF DIO
10
0
H
D
H PA
D
M
H A
D
H PB
D
M
B
L
RT
JT CK
AG
SE
N
T
TDRS
T
TDI
O
TM
S
TC
K
TST
10/100 Ethernet
MAC
FIFO
FIFO
DMA
USB
OHCI
FIFO
DMA
DMA
D
SDRAM
Controller
Fast SRAM
80 Kbytes
WDT
Static
Memory
Controller
9-layer Bus Matrix
PIT
VDDCORE
20GPREG
VDDBU
OSC
SHDN
WKUP
RTT1
PIOB
SHDWC
PIOC
DMA
SRAM
16 Kbytes
Peripheral
Bridge
PIOD
POR
RSTC
VDDCORE
ECC
Controller
PIOA
RTT0
XIN32
XOUT32
20-channel
Peripheral
DMA
2-channel
DMA
ROM
128 Kbytes
PIOE
POR
CompactFlash
NAND Flash
2D
Graphics
Controller
EBI1_
EBI1
NAND Flash
NRST
APB
PDC
MCI0
MCI1
PDC
PDC
TWI
USART0
USART1
USART2
CAN
SPI0
SPI1
PDC
PWMC
TC0
TC1
TC2
AC97C
SDRAM
Controller
DMA
PDC
SSC0
SSC1
USB
Device
Port
Image
Sensor
Interface
I_ IS
D I_
0 P
IS -IS CK
I I_
IS _HS D1
I_ Y 1
V N
IS SYNC
I_ C
M
C
K
SPI0_, SPI1_
IS
6249B–ATARM–14-Dec-06
D
B0
-D
DA C B3
0- DB
DA
C 3
DA
C
K
TW
C TW D
T
C
RTS0- K
C
SC S0- TS
R 2
R K0- TS
D S 2
X
TX 0- CK2
D RD
0- X
TX 2
D
2
CA
N
C T
AN X
R
N X
P
N CS
PC 3
N S
P 2
N CS
PC 1
SP S0
C
M K
O
SI
M
PW
IS
O
M
0PW
TC
M
L
3
TI K0O T
C
A
TI 0 L
O -T K2
B0 IO
-T A2
AC IOB
2
AC97C
AC 97 K
F
AC97RS
9 X
TK 7TX
TF0-T
TD 0-TK1
R 0-T F1
D
D D
M
AR RF0-R 1
Q R 0- D1
0_ K R
D 0-R F1
M K
AR 1
Q
3
D
D
D P
D
M
Transc.
MCI0_, MCI_1
D0-D15
A0/NBS0
A1/NBS2/NWR2
A2-A15, A18-A20
A16/BA0
A17/BA1
NCS0
NCS1/SDCS
NRD
NWR0/NWE
NWR1/NBS1
NWR3/NBS3
SDCK, SDCKE
RAS, CAS
SDWE, SDA10
NANDOE, NANDWE
A21/NANDALE
A22/NANDCLE
NWAIT
A23-A24
NCS4/CFCS0
NCS5/CFCS1
NCS3/NANDCS
A25/CFRNW
CFCE1-CFCE2
D16-D31
NCS2
Static
Memory
Controller
ECC
Controller
D0-D15
A0/NBS0
A1/NWR2
A2-A15/A18-A20
A16/BA0
A17/BA1
NCS0
NRD
NWR0/NWE
NWR1/NBS1
SDCK
A21/NANDALE
A22/NANDCLE
NWAIT
NWR3/NBS3
NCS1/SDCS
NCS2/NANDCS
D16-D31
SDCKE
RAS, CAS
SDWE, SDA10
NANDOE, NANDWE
AT91SAM9263 Block Diagram
SLAVE
2. AT91SAM9263 Block Diagram
Figure 2-1.
4
AT91SAM9263 Preliminary
MASTER
AT91SAM9263 Preliminary
3. Signal Description
Table 3-1 gives details on the signal name classified by peripheral.
Table 3-1.
Signal Description List
Signal Name
Function
Type
Active
Level
Comments
Power Supplies
VDDIOM0
EBI0 I/O Lines Power Supply
Power
1.65V to 3.6V
VDDIOM1
EBI1 I/O Lines Power Supply
Power
1.65V to 3.6V
VDDIOP0
Peripherals I/O Lines Power Supply
Power
2.7V to 3.6V
VDDIOP1
Peripherals I/O Lines Power Supply
Power
1.65V to 3.6V
VDDBU
Backup I/O Lines Power Supply
Power
1.08V to 1.32V
VDDPLL
PLL Power Supply
Power
3.0V to 3.6V
VDDOSC
Oscillator Power Supply
Power
3.0V to 3.6V
VDDCORE
Core Chip Power Supply
Power
1.08V to 1.32V
GND
Ground
Ground
GNDPLL
PLL Ground
Ground
GNDBU
Backup Ground
Ground
Clocks, Oscillators and PLLs
XIN
Main Oscillator Input
Input
XOUT
Main Oscillator Output
XIN32
Slow Clock Oscillator Input
XOUT32
Slow Clock Oscillator Output
PLLRCA
PLL A Filter
Input
PLLRCB
PLL B Filter
Input
PCK0 - PCK3
Programmable Clock Output
Output
Input
Output
Output
Shutdown, Wakeup Logic
SHDN
Shutdown Control
WKUP
Wake-up Input
Driven at 0V only. Do not tie
over VDDBU.
Output
Accepts between 0V and
VDDBU.
Input
ICE and JTAG
NTRST
Test Reset Signal
Input
Low
Pull-up resistor
TCK
Test Clock
Input
No pull-up resistor
TDI
Test Data In
Input
No pull-up resistor
TDO
Test Data Out
TMS
Test Mode Select
Input
No pull-up resistor
JTAGSEL
JTAG Selection
Input
Pull-down resistor. Accepts
between 0V and VDDBU.
RTCK
Return Test Clock
Output
Output
5
6249B–ATARM–14-Dec-06
Table 3-1.
Signal Description List (Continued)
Signal Name
Function
Type
Active
Level
Comments
Embedded Trace Module - 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
NRST
Microcontroller Reset
I/O
TST
Test Mode Select
Input
BMS
Boot Mode Select
Input
Low
Pull-up resistor
Pull-down resistor
Debug Unit - DBGU
DRXD
Debug Receive Data
Input
DTXD
Debug Transmit Data
Output
Advanced Interrupt Controller - AIC
IRQ0 - IRQ1
External Interrupt Inputs
Input
FIQ
Fast Interrupt Input
Input
PIO Controller - PIOA - PIOB - PIOC - PIOD - PIOE
PA0 - PA31
Parallel IO Controller A
I/O
Pulled-up input at reset
PB0 - PB31
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 - PD31
Parallel IO Controller D
I/O
Pulled-up input at reset
PE0 - PE31
Parallel IO Controller E
I/O
Pulled-up input at reset
Direct Memory Access Controller - DMA
DMARQ0-DMARQ3
DMA Requests
Input
External Bus Interface - EBI0 - EBI1
EBIx_D0 - EBIx_D31
Data Bus
I/O
EBIx_A0 - EBIx_A25
Address Bus
EBIx_NWAIT
External Wait Signal
Pulled-up input at reset
Output
Input
0 at reset
Low
Static Memory Controller - SMC
EBI0_NCS0 - EBI0_NCS5,
EBI1_NCS0 - EBI1_NCS2
Chip Select Lines
Output
Low
EBIx_NWR0 -EBIx_NWR3
Write Signal
Output
Low
EBIx_NRD
Read Signal
Output
Low
EBIx_NWE
Write Enable
Output
Low
EBIx_NBS0 - EBIx_NBS3
Byte Mask Signal
Output
Low
CompactFlash Support
EBI0_CFCE1 - EBI0_CFCE2
6
CompactFlash Chip Enable
Output
Low
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Table 3-1.
Signal Description List (Continued)
Type
Active
Level
CompactFlash Output Enable
Output
Low
EBI0_CFWE
CompactFlash Write Enable
Output
Low
EBI0_CFIOR
CompactFlash IO Read
Output
Low
EBI0_CFIOW
CompactFlash IO Write
Output
Low
EBI0_CFRNW
CompactFlash Read Not Write
Output
EBI0_CFCS0 - EBI0_CFCS1
CompactFlash Chip Select Lines
Output
Low
Signal Name
Function
EBI0_CFOE
Comments
NAND Flash Support
EBIx_NANDCS
NAND Flash Chip Select
Output
Low
EBIx_NANDOE
NAND Flash Output Enable
Output
Low
EBIx_NANDWE
NAND Flash Write Enable
Output
Low
SDRAM Controller
EBIx_SDCK
SDRAM Clock
Output
EBIx_SDCKE
SDRAM Clock Enable
Output
High
EBIx_SDCS
SDRAM Controller Chip Select
Output
Low
EBIx_BA0 - EBIx_BA1
Bank Select
Output
EBIx_SDWE
SDRAM Write Enable
Output
Low
EBIx_RAS - EBIx_CAS
Row and Column Signal
Output
Low
EBIx_SDA10
SDRAM Address 10 Line
Output
Multimedia Card Interface
MCIx_CK
Multimedia Card Clock
Output
MCIx_CDA
Multimedia Card Slot A Command
I/O
MCIx_CDB
Multimedia Card Slot B A Command
I/O
MCIx_DA0 - MCIx_DA3
Multimedia Card Slot A Data
I/O
MCIx_DB0 - MCIx_DB3
Multimedia Card Slot B Data
I/O
Universal Synchronous Asynchronous Receiver Transmitter USART
SCKx
USARTx Serial Clock
I/O
TXDx
USARTx Transmit Data
I/O
RXDx
USARTx Receive Data
Input
RTSx
USARTx Request To Send
CTSx
USARTx Clear To Send
Output
Input
Synchronous Serial Controller SSC
TDx
SSCx Transmit Data
Output
RDx
SSCx Receive Data
Input
TKx
SSCx Transmit Clock
I/O
RKx
SSCx Receive Clock
I/O
7
6249B–ATARM–14-Dec-06
Table 3-1.
Signal Description List (Continued)
Signal Name
Function
Type
TFx
SSCx Transmit Frame Sync
I/O
RFx
SSCx Receive Frame Sync
I/O
Active
Level
Comments
AC97 Controller - AC97C
AC97RX
AC97 Receive Signal
Input
AC97TX
AC97 Transmit Signal
Output
AC97FS
AC97 Frame Synchronization Signal
Output
AC97CK
AC97 Clock signal
Input
Timer/Counter - TC
TCLKx
TC Channel x External Clock Input
Input
TIOAx
TC Channel x I/O Line A
I/O
TIOBx
TC Channel x I/O Line B
I/O
Pulse Width Modulation Controller- PWMC
PWMx
Pulse Width Modulation Output
Output
Serial Peripheral Interface - SPI
SPIx_MISO
Master In Slave Out
I/O
SPIx_MOSI
Master Out Slave In
I/O
SPIx_SPCK
SPI Serial Clock
I/O
SPIx_NPCS0
SPI Peripheral Chip Select 0
I/O
Low
SPIx_NPCS1 - SPIx_NPCS3
SPI Peripheral Chip Select
Output
Low
Two-Wire Interface
TWD
Two-wire Serial Data
I/O
TWCK
Two-wire Serial Clock
I/O
CAN Controllers
CANRX
CAN Input
CANTX
CAN Output
Input
Output
LCD Controller - LCDC
LCDD0 - LCDD23
LCD Data Bus
Output
LCDVSYNC
LCD Vertical Synchronization
Output
LCDHSYNC
LCD Horizontal Synchronization
Output
LCDDOTCK
LCD Dot Clock
Output
LCDDEN
LCD Data Enable
Output
LCDCC
LCD Contrast Control
Output
Ethernet 10/100
ETXCK
Transmit Clock or Reference Clock
Input
MII only, REFCK in RMII
ERXCK
Receive Clock
Input
MII only
8
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Table 3-1.
Signal Description List (Continued)
Type
Active
Level
Signal Name
Function
Comments
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
RXDV in MII, CRSDV in RMII
ERX0-ERX3
Receive Data
Input
ERX0-ERX1 only in RMII
ERXER
Receive Error
Input
ECRS
Carrier Sense and Data Valid
Input
MII only
ECOL
Collision Detect
Input
MII only
EMDC
Management Data Clock
EMDIO
Management Data Input/Output
EF100
Force 100Mbit/sec.
Output
I/O
Output
High
RMII only
USB Device Port
DDM
USB Device Port Data -
Analog
DDP
USB Device Port Data +
Analog
USB Host Port
HDPA
USB Host Port A Data +
Analog
HDMA
USB Host Port A Data -
Analog
HDPB
USB Host Port B Data +
Analog
HDMB
USB Host Port B Data -
Analog
Image Sensor Interface - ISI
ISI_D0-ISI_D11
Image Sensor Data
Input
ISI_MCK
Image Sensor Reference Clock
ISI_HSYNC
Image Sensor Horizontal Synchro
Input
ISI_VSYNC
Image Sensor Vertical Synchro
Input
ISI_PCK
Image Sensor Data Clock
Input
Output
9
6249B–ATARM–14-Dec-06
4. Package and Pinout
The AT91SAM9263 is available in a 324-ball Green BGA package, 15 x 15 mm, 0.8mm ball
pitch.
4.1
324-ball LFBGA Package Outline
Figure 4-1 shows the orientation of the 324-ball BGA package.
A detailed mechanical description is given in the section “AT91SAM9263 Mechanical Characteristics” in the product datasheet.
Figure 4-1.
324-ball BGA Pinout (Top View)
TOP VIEW
V
U
T
R
P
N
M
L
K
J
H
G
F
E
D
C
B
A
BALL A1
10
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
4.2
324-ball BGA Package Pinout
Table 4-1.
AT91SAM9263 Pinout for 324-ball BGA Package
Pin
Signal Name
Pin
Signal Name
Pin
Signal Name
Pin
Signal Name
A1
EBI0_D2
E10
PC31
K1
PE6
P10
EBI1_NCS0
A2
EBI0_SDCKE
E11
PC22
K2
PD28
P11
EBI1_NWE_NWR0
A3
EBI0_NWE_NWR0
E12
PC15
K3
PE0
P12
EBI1_D4
A4
EBI0_NCS1_SDCS
E13
PC11
K4
PE1
P13
EBI1_D10
A5
EBI0_A19
E14
PC4
K5
PD27
P14
PA3
A6
EBI0_A11
E15
PB30
K6
PD31
P15
PA2
A7
EBI0_A10
E16
PC0
K7
PD29
P16
PE28
A8
EBI0_A5
E17
PB31
K8
PD25
P17
TDI
A9
EBI0_A1_NBS2_NWR2
E18
HDPA
K9
GND
P18
PLLRCB
A10
PD4
F1
PD7
K10
VDDIOM0
R1
XOUT32
A11
PC30
F2
EBI0_D13
K11
GND
R2
TST
A12
PC26
F3
EBI0_D9
K12
VDDIOM0
R3
PA18
A13
PC24
F4
EBI0_D11
K13
PB3/BMS
R4
PA25
A14
PC19
F5
EBI0_D12
K14
PA14
R5
PA30
A15
PC12
F6
EBI0_NCS0
K15
PA15
R6
EBI1_A2
A16
VDDCORE
F7
EBI0_A16_BA0
K16
PB1
R7
EBI1_A14
A17
VDDIOP0
F8
EBI0_A12
K17
PB0
R8
EBI1_A13
A18
DDP
F9
EBI0_A6
K18
PB2
R9
EBI1_A17_BA1
B1
EBI0_D4
F10
PD3
L1
PE10
R10
EBI1_D1
B2
EBI0_NANDOE
F11
PC27
L2
PE4
R11
EBI1_D8
B3
EBI0_CAS
F12
PC18
L3
PE9
R12
EBI1_D12
B4
EBI0_RAS
F13
PC13
L4
PE7
R13
EBI1_D15
B5
EBI0_NBS3_NWR3
F14
PB26
L5
PE5
R14
PE26
B6
EBI0_A22
F15
PB25
L6
PE2
R15
EBI1_SDCK
B7
EBI0_A15
F16
PB29
L7
PE3
R16
PE30
B8
EBI0_A7
F17
PB27
L8
VDDIOP1
R17
TCK
B9
EBI0_A4
F18
HDMA
L9
VDDIOM1
R18
XOUT
B10
PD0
G1
PD17
L10
VDDIOM0
T1
VDDOSC
B11
PC28
G2
PD12
L11
VDDIOP0
T2
VDDIOM1
B12
PC21
G3
PD6
L12
GNDBU
T3
PA19
B13
PC17
G4
EBI0_D14
L13
PA13
T4
PA21
B14
PC9
G5
PD5
L14
PB4
T5
PA26
B15
PC7
G6
PD8
L15
PA9
T6
PA31
B16
PC5
G7
PD10
L16
PA12
T7
EBI1_A7
B17
PB16
G8
GND
L17
PA10
T8
EBI1_A12
B18
DDM
G9
NC(1)
L18
PA11
T9
EBI1_A18
C1
EBI0_D6
G10
GND
M1
PE18
T10
EBI1_D0
C2
EBI0_D0
G11
GND
M2
PE14
T11
EBI1_D7
C3
EBI0_NANDWE
G12
GND
M3
PE15
T12
EBI1_D14
C4
EBI0_SDWE
G13
PB21
M4
PE11
T13
PE23
C5
EBI0_SDCK
G14
PB20
M5
PE13
T14
PE25
C6
EBI0_A21
G15
PB23
M6
PE12
T15
PE29
C7
EBI0_A13
G16
PB28
M7
PE8
T16
PE31
C8
EBI0_A8
G17
PB22
M8
VDDBU
T17
GNDPLL
C9
EBI0_A3
G18
PB18
M9
EBI1_A21
T18
XIN
C10
PD2
H1
PD24
M10
VDDIOM1
U1
PA17
C11
PC29
H2
PD13
M11
GND
U2
PA20
C12
PC23
H3
PD15
M12
GND
U3
PA23
C13
PC14
H4
PD9
M13
VDDIOM1
U4
PA24
C14
PC8
H5
PD11
M14
PA6
U5
PA28
11
6249B–ATARM–14-Dec-06
Table 4-1.
AT91SAM9263 Pinout for 324-ball BGA Package
Pin
Signal Name
Pin
Signal Name
Pin
Signal Name
Pin
Signal Name
C15
PC3
H6
PD14
M15
PA4
U6
EBI1_A0_NBS0
C16
GND
H7
PD16
M16
PA7
U7
EBI1_A5
C17
VDDIOP0
H8
VDDIOM0
M17
PA5
U8
EBI1_A10
C18
HDPB
H9
GND
M18
PA8
U9
EBI1_A16_BA0
D1
EBI0_D10
H10
VDDCORE
N1
NC
U10
EBI1_NRD
D2
EBI0_D3
H11
GND
N2
NC
U11
EBI1_D3
D3
NC(1)
H12
PB19
N3
PE19
U12
EBI1_D13
D4
EBI0_D1
H13
PB17
N4
NC(1)
U13
PE22
D5
EBI0_A20
H14
PB15
N5
PE17
U14
PE27
D6
EBI0_A17_BA1
H15
PB13
N6
PE16
U15
RTCK
D7
EBI0_A18
H16
PB24
N7
EBI1_A6
U16
NTRST
D8
EBI0_A9
H17
PB14
N8
EBI1_A11
U17
VDDPLLA
D9
EBI0_A2
H18
PB12
N9
EBI1_A22
U18
PLLRCA
D10
PD1
J1
PD30
N10
EBI1_D2
V1
VDDCORE
D11
PC25
J2
PD26
N11
EBI1_D6
V2
PA22
D12
PC20
J3
PD22
N12
EBI1_D9
V3
PA27
D13
PC6
J4
PD19
N13
GND
V4
PA29
D14
PC16
J5
PD18
N14
GNDPLL
V5
EBI1_A1_NWR2
D15
PC10
J6
PD23
N15
PA1
V6
EBI1_A3
D16
PC2
J7
PD21
N16
PA0
V7
EBI1_A9
D17
PC1
J8
PD20
N17
TMS
V8
EBI1_A15
D18
HDMB
J9
GND
N18
TDO
V9
EBI1_A20
E1
EBI0_D15
J10
GND
P1
XIN32
V10
EBI1_NBS1_NWR1
E2
EBI0_D7
J11
GND
P2
SHDN
V11
EBI1_D5
E3
EBI0_D5
J12
PB11
P3
PA16
V12
EBI1_D11
E4
EBI0_D8
J13
PB9
P4
WKUP
V13
PE21
E5
EBI0_NBS1_NWR1
J14
PB10
P5
JTAGSEL
V14
PE24
E6
EBI0_NRD
J15
PB5
P6
PE20
V15
NRST
E7
EBI0_A14
J16
PB6
P7
EBI1_A8
V16
GND
E8
EBI0_SDA10
J17
PB7
P8
EBI1_A4
V17
GND
E9
EBI0_A0_NBS0
J18
PB8
P9
EBI1_A19
V18
VDDPLLB
Note:
1. NC pins must be left unconnected.
5. Power Considerations
5.1
Power Supplies
AT91SAM9263 has several types of power supply pins:
• VDDCORE pins: Power the core, including the processor, the embedded memories and the
peripherals; voltage ranges from 1.08V to 1.32V, 1.2V nominal.
• VDDIOM0 and VDDIOM1 pins: Power the External Bus Interface 0 I/O lines and the External
Bus Interface 1 I/O lines, respectively; voltage ranges between 1.65V and 1.95V (1.8V
nominal) or between 3.0V and 3.6V (3.3V nominal).
• VDDIOP0 pins: Power the Peripheral I/O lines and the USB transceivers; voltage ranges from
2.7V to 3.6V, 3.3V nominal.
• VDDIOP1 pins: Power the Peripheral I/O lines involving the Image Sensor Interface; voltage
ranges from 1.65V to 3.6V, 1.8V, 2.5V, 3V or 3.3V nominal.
• VDDBU pin: Powers the Slow Clock oscillator and a part of the System Controller; voltage
ranges from 1.08V to 1.32V, 1.2V nominal.
12
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
• VDDPLL pin: Powers the PLL cells; voltage ranges from 3.0V to 3.6V, 3.3V nominal.
• VDDOSC pin: Powers the Main Oscillator cells; voltage ranges from 3.0V to 3.6V, L3.3V
nominal.
The power supplies VDDIOM0, VDDIOM1 and VDDIOP0, VDDIOP1 are identified in the pinout
table and the multiplexing tables. These supplies enable the user to power the device differently
for interfacing with memories and for interfacing with peripherals.
Ground pins GND are common to VDDOSC, VDDCORE, VDDIOM0, VDDIOM1, VDDIOP0 and
VDDIOP1 pins power supplies. Separated ground pins are provided for VDDBU and VDDPLL.
These ground pins are respectively GNDBU and GNDPLL.
5.2
Power Consumption
The AT91SAM9263 consumes about 700 µA of static current on VDDCORE at 25°C. This static
current rises at up to 7 mA if the temperature increases to 85°C.
On VDDBU, the current does not exceed 3 µA @25°C, but can rise at up to 20 µA @85°C. A
software-controllable switch to VDDCORE guarantees zero power consumption on the battery
when the system is on.
For dynamic power consumption, the AT91SAM9263 consumes a maximum of 70 mA on
VDDCORE at maximum conditions (1.2V, 25°C, processor running full-performance algorithm).
5.3
Programmable I/O Lines Power Supplies
The power supply pins VDDIOM0 and VDDIOM1 accept two voltage ranges. This allows the
device to reach its maximum speed, either out of 1.8V or 3.0V external memories.
The maximum speed is 100 MHz on the pin SDCK (SDRAM Clock) loaded with 30 pF for power
supply at 1.8V and 50pF for power supply at 3.3V. The other signals (control, address and data
signals) do not go over 50MHz.
The voltage ranges are determined by programming registers in the Chip Configuration registers
located in the Matrix User Interface.
At reset, the selected voltage defaults to 3.3V nominal and power supply pins can accept either
1.8V or 3.3V. However, the device cannot reach its maximum speed if the voltage supplied to
the pins is only 1.8V without reprogramming the EBI0 voltage range. The user must be sure to
program the EBI0 voltage range before getting the device out of its Slow Clock Mode.
6. I/O Line Considerations
6.1
JTAG Port Pins
TMS, TDI and TCK are Schmitt trigger inputs and have no pull-up resistors.
TDO and RTCK are outputs, driven at up to VDDIOP0, and have no pull-up resistors.
The JTAGSEL pin is used to select the JTAG boundary scan when asserted at a high level
(VDDBU). It integrates a permanent pull-down resistor of about 15 kΩ to GNDBU, so that it can
be left unconnected for normal operations.
The NTRST signal is described in Section 6.3.
All JTAG signals except JTAGSEL (VDDBU) are supplied with VDDIOP0.
13
6249B–ATARM–14-Dec-06
6.2
Test Pin
The TST pin is used for manufacturing test purposes when asserted high. It integrates a permanent pull-down resistor of about 15 kΩ to GNDBU, so that it can be left unconnected for normal
operations. Driving this line at a high level leads to unpredictable results.
This pin is supplied with VDDBU.
6.3
Reset Pins
NRST is an open-drain output integrating a non-programmable pull-up resistor. It can be driven
with voltage at up to VDDIOP0.
NTRST is an input which allows reset of the JTAG Test Access port. It has no action on the
processor.
As the product integrates power-on reset cells, which manage the processor and the JTAG
reset, the NRST and NTRST pins can be left unconnected.
The NRST and NTRST pins both integrate a permanent pull-up resistor of 100 kΩ minimum to
VDDIOP0.
The NRST signal is inserted in the Boundary Scan.
6.4
PIO Controllers
All the I/O lines managed by the PIO Controllers integrate a programmable pull-up resistor of
100 kΩ minimum. 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 require to be enabled as Peripheral
at reset. This is explicitly indicated in the column “Reset State” of the PIO Controller multiplexing
tables on page 34 and following.
6.5
Shutdown Logic Pins
The SHDN pin is an output only, which is driven by the Shutdown Controller.
The pin WKUP is an input only. It can accept voltages only between 0V and VDDBU.
7. Processor and Architecture
7.1
ARM926EJ-S Processor
• RISC Processor based on ARM v5TEJ Harvard Architecture with Jazelle technology for Java
acceleration
• Two Instruction Sets
– ARM High-performance 32-bit Instruction Set
– Thumb High Code Density 16-bit Instruction Set
• DSP Instruction Extensions
• 5-stage Pipeline Architecture
– Instruction Fetch (F)
– Instruction Decode (D)
14
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
– Execute (E)
– Data Memory (M)
– Register Write (W)
• 16 Kbyte Data Cache, 16 Kbyte Instruction Cache
– Virtually-addressed 4-way Associative Cache
– Eight words per line
– Write-through and Write-back Operation
– Pseudo-random or Round-robin Replacement
• Write Buffer
– Main Write Buffer with 16-word Data Buffer and 4-address Buffer
– DCache Write-back Buffer with 8-word Entries and a Single Address Entry
– Software Control Drain
• Standard ARM v4 and v5 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 page
– 16 embedded domains
• Bus Interface Unit (BIU)
– Arbitrates and Schedules AHB Requests
– Separate Masters for both instruction and data access providing complete Matrix
system flexibility
– Separate Address and Data Buses for both the 32-bit instruction interface and the
32-bit data interface
– On Address and Data Buses, data can be 8-bit (Bytes), 16-bit (Half-words) or 32-bit
(Words)
7.2
Bus Matrix
• 9-layer Matrix, handling requests from 9 masters
• Programmable Arbitration strategy
– Fixed-priority Arbitration
– Round-Robin Arbitration, either with no default master, last accessed default master
or fixed default master
• Burst Management
– Breaking with Slot Cycle Limit Support
– Undefined Burst Length Support
• One Address Decoder provided per Master
– Three different slaves may be assigned to each decoded memory area: one for
internal boot, one for external boot, one after remap
• Boot Mode Select
– Non-volatile Boot Memory can be internal or external
– Selection is made by BMS pin sampled at reset
• Remap Command
15
6249B–ATARM–14-Dec-06
– Allows Remapping of an Internal SRAM in Place of the Boot Non-Volatile Memory
– Allows Handling of Dynamic Exception Vectors
7.3
Matrix Masters
The Bus Matrix of the AT91SAM9263 manages nine masters, thus each master can perform an
access concurrently with others to an available slave peripheral or memory.
Each master has its own decoder, which is defined specifically for each master.
Table 7-1.
7.4
List of Bus Matrix Masters
Master 0
ARM926™ Instruction
Master 1
ARM926 Data
Master 2
Peripheral DMA Controller
Master 3
LCD Controller
Master 4
2D Graphic Controller
Master 5
Image Sensor Interface
Master 6
DMA Controller
Master 7
Ethernet MAC
Master 8
OHCI USB Host Controller
Matrix Slaves
The Bus Matrix of the AT91SAM9263 manages eight slaves. Each slave has its own arbiter,
thus allowing to program a different arbitration per slave.
The LCD Controller, the DMA Controller, the USB OTG and the USB Host have a user interface
mapped as a slave on the Matrix. They share the same layer, as programming them does not
require a high bandwidth.
Table 7-2.
List of Bus Matrix Slaves
Slave 0
Internal 80 Kbyte SRAM
Slave 1
Internal 16 Kbyte SRAM Bank
Slave 2
Reserved
Slave 3
Internal ROM
LCD Controller User Interface
Slave 4
DMA Controller User Interface
USB Host User Interface
16
Slave 5
External Bus Interface 0
Slave 6
External Bus Interface 1
Slave 7
Peripheral Bridge
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
7.5
Master to Slave Access
In most cases, all the masters can access all the slaves. However, some paths do not make
sense, for example, allowing access from the Ethernet MAC to the Internal Peripherals. Thus,
these paths are forbidden or simply not wired, and are shown as “-” in Table 7-3.
Table 7-3.
Masters to Slaves Access
Master
0&1
2
3
4
5
6
7
8
Slave
ARM926
Instruction
& Data
Peripheral
DMA
Controller
LCD
Controller
2D
Graphics
Controller
Image
Sensor
Interface
DMA
Controller
Ethernet
MAC
OHCI USB
Host
Controller
0
Internal 80 Kbyte
SRAM
X
X
X
X
X
X
X
X
1
Internal 16 Kbyte
SRAM Bank
X
X
X
X
X
X
X
X
Internal ROM
X
X
X
X
X
X
X
X
LCD Controller
User Interface
X
-
-
-
-
-
-
-
DMA Controller
User Interface
X
-
-
-
-
-
-
-
USB Host User
Interface
X
-
-
-
-
-
-
-
5
External Bus
Interface 0
X
X
X
X
X
X
X
X
6
External Bus
Interface 1
X
X
X
X
X
X
X
X
7
Peripheral Bridge
X
X
-
-
-
X
-
-
2
3
4
7.6
Peripheral DMA Controller
• Acts as one Matrix Master
• Allows data transfers between a peripheral and memory without any intervention of the
processor
• Next Pointer support, removes heavy real-time constraints on buffer management.
• Twenty channels
– Two for each USART
– Two for the Debug Unit
– Two for each Serial Synchronous Controller
– Two for each Serial Peripheral Interface
– Two for the AC97 Controller
– One for each Multimedia Card Interface
The Peripheral DMA Controller handles transfer requests from the channel according to the following priorities (low to high priorities):
– DBGU Transmit Channel
– USART2 Transmit Channel
17
6249B–ATARM–14-Dec-06
– USART1 Transmit Channel
– USART0 Transmit Channel
– AC97 Transmit Channel
– SPI1 Transmit Channel
– SPI0 Transmit Channel
– SSC1 Transmit Channel
– SSC0 Transmit Channel
– DBGU Receive Channel
– USART2 Receive Channel
– USART1 Receive Channel
– USART0 Receive Channel
– AC97 Receive Channel
– SPI1 Receive Channel
– SPI0 Receive Channel
– SSC1 Receive Channel
– SSC0 Receive Channel
– MCI1 Transmit/Receive Channel
– MCI0 Transmit/Receive Channel
7.7
DMA Controller
• Acts as one Matrix Master
• Embeds 2 unidirectional channels with programmable priority
• Address Generation
– Source/destination address programming
– Address increment, decrement or no change
– DMA chaining support for multiple non-contiguous data blocks through use of linked
lists
– Scatter support for placing fields into a system memory area from a contiguous
transfer. Writing a stream of data into non-contiguous fields in system memory.
– Gather support for extracting fields from a system memory area into a contiguous
transfer
– User enabled auto-reloading of source, destination and control registers from initially
programmed values at the end of a block transfer
– Auto-loading of source, destination and control registers from system memory at end
of block transfer in block chaining mode
– Unaligned system address to data transfer width supported in hardware
• Channel Buffering
– Two 8-word FIFOs
– Automatic packing/unpacking of data to fit FIFO width
• Channel Control
– Programmable multiple transaction size for each channel
– Support for cleanly disabling a channel without data loss
18
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
– Suspend DMA operation
– Programmable DMA lock transfer support.
• Transfer Initiation
– Supports four external DMA Requests
– Support for software handshaking interface. Memory mapped registers can be used
to control the flow of a DMA transfer in place of a hardware handshaking interface
• Interrupt
– Programmable interrupt generation on DMA transfer completion, Block transfer
completion, Single/Multiple transaction completion or Error condition
7.8
Debug and Test Features
• ARM926 Real-time In-circuit Emulator
– Two real-time Watchpoint Units
– Two Independent Registers: Debug Control Register and Debug Status Register
– Test Access Port Accessible through JTAG Protocol
– Debug Communications Channel
• Debug Unit
– Two-pin UART
– Debug Communication Channel Interrupt Handling
– Chip ID Register
• Embedded Trace Macrocell: ETM9™
– Medium+ Level Implementation
– Half-rate Clock Mode
– Four Pairs of Address Comparators
– Two Data Comparators
– Eight Memory Map Decoder Inputs
– Two 16-bit Counters
– One 3-stage Sequencer
– One 45-byte FIFO
• IEEE1149.1 JTAG Boundary-scan on All Digital Pins
19
6249B–ATARM–14-Dec-06
8. Memories
Figure 8-1.
AT91SAM9263 Memory Mapping
Internal Memory Mapping
Address Memory Space
0x0000 0000
0x0000 0000
Internal Memories
Boot Memory (1)
0x0010 0000
256M Bytes
ITCM (2)
0x0020 0000
0x0FFF FFFF
DTCM (2)
0x1000 0000
EBI0
Chip Select 0
0x0030 0000
256M Bytes
SRAM (2)
0x0040 0000
ROM
0x1FFF FFFF
0x2000 0000
0x2FFF FFFF
EBI0
Chip Select 1/
EBI0 SDRAMC
0x0050 0000
16K SRAM0
256M Bytes
0x0060 0000
LCD Controller
EBI0
Chip Select 2
0x0080 0000
256M Bytes
DMAC
0x0090 0000
0x3FFF FFFF
EBI0
Chip Select 3/
NANDFlash
0x5FFF FFFF
0x6000 0000
0x6FFF FFFF
Reserved
0x00A0 0000
256M Bytes
USB HOST
0x00B0 0000
0x4FFF FFFF
0x5000 0000
Reserved
0x0070 0000
0x3000 0000
0x4000 0000
Notes:
(1) Can be ROM, EBI0_NCS0 or SRAM
depending on BMS and REMAP
(2) Software programmable
Reserved
EBI0
Chip Select 4/
Compact Flash
Slot 0
EBI0
Chip Select 5/
Compact Flash
Slot 1
Peripheral Mapping
256M Bytes
0xF000 0000
Reserved
16K Bytes
UDP
16K Bytes
0xFFF7 8000
256M Bytes
0x7000 0000
0xFFF7 C000
System Controller Mapping
0xFFFF C000
TCO, TC1, TC2
16K Bytes
MCI0
16K Bytes
0xFFFF E000
MCI1
16K Bytes
0xFFFF E200
TWI
16K Bytes
0xFFFF E400
USART0
16K Bytes
0xFFFF E600
USART1
16K Bytes
USART2
16K Bytes
SSC0
16K Bytes
SSC1
16K Bytes
AC97C
16K Bytes
SPI0
16K Bytes
SPI1
16K Bytes
CAN0
16K Bytes
Reserved
0xFFF8 0000
EBI1
Chip Select 0
256M Bytes
0x7FFF FFFF
0x8000 0000
0xFFF8 8000
EBI1
Chip Select 1/
EBI1 SDRAMC
256M Bytes
0x8FFF FFFF
EBI1
Chip Select 2/
NANDFlash
256M Bytes
0xFFF9 4000
0xFFF9 8000
0x9FFF FFFF
0xA000 0000
0xFFFA 8000
0xFFFF EA00
0xFFFF EC00
0xFFFF F200
PWMC
0xFFFF F800
EMAC
16K Bytes
Reserved
16K Bytes
0xFFFC 0000
0xFFFC 4000
16K Bytes
0xFFFC 8000
16K Bytes
0xFFFC C000
Reserved
0xFFFF C000
SYSC
20
0xFFFF FFFF
512 Bytes
AIC
512 bytes
PIOA
512 bytes
PIOB
512 Bytes
PIOC
512 bytes
PIOD
512 bytes
PIOE
512 bytes
PMC
256 Bytes
0xFFFF FD00
RSTC
16 Bytes
0xFFFF FD10
SHDWC
16 Bytes
RTT0
16 Bytes
0xFFFF FD30
PIT
16 Bytes
0xFFFF FD40
WDT
16 Bytes
0xFFFF FD50
0xFFFF FD60
RTT1
16 Bytes
GPBR
80 Bytes
0xFFFF FC00
2DGE
DBGU
16K Bytes
0xFFFB C000
ISI
512 Bytes
0xFFFF F600
0xFFFF FA00
256M Bytes
512 Bytes
0xFFFF F400
0xFFFB 8000
Internal Peripherals
SMC1
MATRIX
0xFFFF F000
0xFFFB 0000
Reserved
0xFFFF FFFF
512 Bytes
CCFG
0xFFFA C000
0xEFFF FFFF
512 bytes
SDRAMC1
0xFFFF E800
0xFFFA 4000
0xF000 0000
512 Bytes
ECC1
0xFFFF EE00
0xFFFA 0000
1,280M Bytes
512 Bytes
SMC0
0xFFFF ED10
0xFFF9 C000
Undefined
(Abort)
512 Bytes
0xFFF8 C000
0xFFF9 0000
0x9000 0000
ECC0
SDRAMC0
0xFFF8 4000
16K Bytes
0xFFFF FD20
0xFFFF FDB0
Reserved
0xFFFF FFFF
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
A first level of address decoding is performed by the Bus Matrix, i.e., the implementation of the
Advanced High Performance Bus (AHB) for its master and slave interfaces with additional
features.
Decoding breaks up the 4G bytes of address space into 16 banks of 256M bytes. The banks 1 to
9 are directed to the EBI0 that associates these banks to the external chip selects EBI0_NCS0
to EBI0_NCS5 and EBI1_NCS0 to EBI1_NCS2. The bank 0 is reserved for the addressing of the
internal memories, and a second level of decoding provides 1M bytes of internal memory area.
Bank 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.
Each master has its own bus and its own decoder, thus allowing a different memory mapping for
each master. However, in order to simplify the mappings, all the masters have a similar address
decoding.
Regarding Master 0 and Master 1 (ARM926 Instruction and Data), three different slaves are
assigned to the memory space decoded at address 0x0: one for internal boot, one for external
boot and one after remap. Refer to Table 8-1, “Internal Memory Mapping,” on page 21 for
details.
A complete memory map is presented in Figure 8-1 on page 20.
8.1
Embedded Memories
• 128 Kbyte ROM
– Single Cycle Access at full matrix speed
• One 80 Kbyte Fast SRAM
– Single Cycle Access at full matrix speed
– Supports ARM926EJ-S TCM interface at full processor speed
– Allows internal Frame Buffer for up to 1/4 VGA 8 bpp screen
• 16 Kbyte Fast SRAM
– Single Cycle Access at full matrix speed
8.1.1
Internal Memory Mapping
Table 8-1 summarizes the Internal Memory Mapping, depending on the Remap status and the
BMS state at reset.
Table 8-1.
Internal Memory Mapping
REMAP = 0
Address
0x0000 0000
8.1.1.1
REMAP = 1
BMS = 1
BMS = 0
ROM
EBI0_NCS0
SRAM C
Internal 80 Kbyte Fast SRAM
The AT91SAM9263 device embeds a high-speed 80 Kbyte SRAM. This internal SRAM is split
into three areas. Its memory mapping is presented in Figure 8-1 on page 20.
• Internal SRAM A is the ARM926EJ-S Instruction TCM. The user can map this SRAM block
anywhere in the ARM926 instruction memory space using CP15 instructions and the TCR
21
6249B–ATARM–14-Dec-06
configuration register located in the Chip Configuration User Interface. This SRAM block is
also accessible by the ARM926 Data Master and by the AHB Masters through the AHB bus
at address 0x0010 0000.
• Internal SRAM B is the ARM926EJ-S Data TCM. The user can map this SRAM block
anywhere in the ARM926 data memory space using CP15 instructions. This SRAM block is
also accessible by the ARM926 Data Master and by the AHB Masters through the AHB bus
at address 0x0020 0000.
• Internal SRAM C is only accessible by all the AHB Masters. After reset and until the Remap
Command is performed, this SRAM block is accessible through the AHB bus at address
0x0030 0000 by all the AHB Masters. After Remap, this SRAM block also becomes
accessible through the AHB bus at address 0x0 by the ARM926 Instruction and the ARM926
Data Masters.
Within the 80 Kbytes of SRAM available, the amount of memory assigned to each block is software programmable as a multiple of 16 Kbytes as shown in Table 8-2. This table provides the
size of the Internal SRAM C according to the size of the internal SRAM A and the internal SRAM
B.
Table 8-2.
Internal SRAM Block Size
Internal SRAM A (ITCM) Size
Internal SRAM C
Internal SRAM B
(DTCM) size
0
16 Kbytes
32 Kbytes
0
80 Kbytes
64 Kbytes
48 Kbytes
16 Kbytes
64 Kbytes
48 Kbytes
32 Kbytes
32 Kbytes
48 Kbytes
32 Kbytes
16 Kbytes
Note that among the five 16 Kbyte blocks making up the Internal SRAM, one is permanently
assigned to Internal SRAM C.
At reset, the whole memory (80 Kbytes) is assigned to Internal SRAM C.
The memory blocks assigned to SRAM A, SRAM B and SRAM C areas are not contiguous and
when the user dynamically changes the Internal SRAM configuration, the new 16 Kbyte block
organization may affect the previous configuration from a software point of view.
Table 8-3 illustrates different configurations and the related 16 Kbyte blocks assignments (RB0
to RB4).
Table 8-3.
16 Kbyte Block Allocation
Configuration examples and related 16 Kbyte block assignments
Decoded
Area
Address
ITCM = 0 Kbyte
DTCM = 0 Kbyte
AHB = 80 Kbytes (1)
ITCM = 32 Kbytes
DTCM = 32 Kbytes
AHB = 16 Kbytes
ITCM = 16 Kbytes
DTCM = 32 Kbytes
AHB = 32 Kbytes
ITCM = 32 Kbytes
DTCM = 16 Kbytes
AHB = 32 Kbytes
ITCM = 16 Kbytes
DTCM = 16 Kbytes
AHB = 48 Kbytes
RB1
RB1
RB1
Internal
SRAM A
(ITCM)
0x0010 0000
RB1
0x0010 4000
RB0
Internal
SRAM B
(DTCM)
0x0020 0000
RB3
RB3
0x0020 4000
RB2
RB2
22
RB0
RB3
RB3
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Table 8-3.
16 Kbyte Block Allocation (Continued)
Configuration examples and related 16 Kbyte block assignments
Decoded
Area
Internal
SRAM C
(AHB)
Note:
ITCM = 0 Kbyte
DTCM = 0 Kbyte
AHB = 80 Kbytes (1)
ITCM = 32 Kbytes
DTCM = 32 Kbytes
AHB = 16 Kbytes
ITCM = 16 Kbytes
DTCM = 32 Kbytes
AHB = 32 Kbytes
ITCM = 32 Kbytes
DTCM = 16 Kbytes
AHB = 32 Kbytes
ITCM = 16 Kbytes
DTCM = 16 Kbytes
AHB = 48 Kbytes
0x0030 0000
RB4
RB4
RB4
RB4
RB4
0x0030 4000
RB3
RB0
RB2
RB2
0x0030 8000
RB2
0x0030 C000
RB1
0x0031 0000
RB0
Address
RB0
1. Configuration after reset.
When accessed from the Bus Matrix, the internal 80 Kbytes of Fast SRAM is single cycle accessible at full matrix speed (MCK). When accessed from the processor’s TCM Interface, they are
also single cycle accessible at full processor speed.
8.1.1.2
8.1.2
Internal 16 Kbyte Fast SRAM
The AT91SAM9263 integrates a 16 Kbyte SRAM, mapped at address 0x0050 0000. This SRAM
is single cycle accessible at full Bus Matrix speed.
Boot Strategies
The system always boots at address 0x0. To ensure maximum boot possibilities, the memory
layout can be changed with two parameters.
REMAP allows the user to layout the internal SRAM bank to 0x0. This is done by software once
the system has booted. When REMAP = 1, BMS is ignored. Refer to the section “AT91SAM9263
Bus Matrix” in the product datasheet for more details.
When REMAP = 0, BMS allows the user to layout at address 0x0 either the ROM or an external
memory. This is done via hardware at reset.
Note:
Memory blocks not affected by these parameters can always be seen at their specified base
addresses. See the complete memory map presented in Figure 8-1 on page 20.
The AT91SAM9263 Bus Matrix manages a boot memory that depends on the level on the pin
BMS at reset. The internal memory area mapped between address 0x0 and 0x000F FFFF is
reserved to this effect.
If BMS is detected at 1, the boot memory is the embedded ROM.
If BMS is detected at 0, the boot memory is the memory connected on the Chip Select 0 of the
External Bus Interface.
8.1.2.1
BMS = 1, Boot on Embedded ROM
The system boots on Boot Program.
• Boot at slow clock
• Auto baudrate detection
• 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 on a non-volatile memory
23
6249B–ATARM–14-Dec-06
– SPI DataFlash® connected on NPCS0 of the SPI0
• Interface with SAM-BA™ Graphic User Interface to enable code loading via:
– Serial communication on a DBGU
– USB Bulk Device Port
8.1.2.2
BMS = 0, Boot on External Memory
• Boot at slow clock
• Boot with the default configuration for the Static Memory Controller, byte select mode, 16-bit
data bus, Read/Write controlled by Chip Select, allows boot on 16-bit non-volatile memory.
The customer-programmed software must perform a complete configuration.
To speed up the boot sequence when booting at 32 kHz EBI0 CS0 (BMS=0) the user must:
1. Program the PMC (main oscillator enable or bypass mode).
2. Program and Start the PLL.
3. Reprogram the SMC setup, cycle, hold, mode timings registers for CS0 to adapt them
to the new clock.
4. Switch the main clock to the new value.
8.2
External Memories
The external memories are accessed through the External Bus Interfaces 0 and 1. Each Chip
Select line has a 256 Mbyte memory area assigned.
Refer to Figure 8-1 on page 20.
8.2.1
8.2.1.1
External Bus Interfaces
The AT91SAM9263 features two External Bus Interfaces to offer more bandwidth to the system
and to prevent bottlenecks while accessing external memories.
External Bus Interface 0
• Optimized for Application Memory Space support
• Integrates three External Memory Controllers:
– Static Memory Controller
– SDRAM Controller
– ECC Controller
• Additional logic for NANDFlash and CompactFlash
• Optional Full 32-bit External Data Bus
• Up to 26-bit Address Bus (up to 64 Mbytes linear per chip select)
• Up to 6 Chip Selects, Configurable Assignment:
– Static Memory Controller on NCS0
– SDRAM Controller or Static Memory Controller on NCS1
– Static Memory Controller on NCS2
– Static Memory Controller on NCS3, Optional NAND Flash support
– Static Memory Controller on NCS4 - NCS5, Optional CompactFlash support
24
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
8.2.1.2
External Bus Interface 1
• Allows supporting an external Frame Buffer for the embedded LCD Controller without
impacting processor performance
• Integrates three External Memory Controllers:
– Static Memory Controller
– SDRAM Controller
– ECC Controller
• Additional logic for NANDFlash
• Optional Full 32-bit External Data Bus
• Up to 23-bit Address Bus (up to 8 Mbytes linear)
• Up to 3 Chip Selects, Configurable Assignment:
– Static Memory Controller on NCS0
– SDRAM Controller or Static Memory Controller on NCS1
– Static Memory Controller on NCS2, Optional NAND Flash support
8.2.2
Static Memory Controller
• 8-, 16- or 32-bit Data Bus
• Multiple Access Modes supported
– Byte Write or Byte Select Lines
– Asynchronous read in Page Mode supported (4- up to 32-byte page size)
• Multiple device adaptability
– Compliant with LCD Module
– Control signals programmable setup, pulse and hold time for each Memory Bank
• Multiple Wait State Management
– Programmable Wait State Generation
– External Wait Request
– Programmable Data Float Time
• Slow Clock mode supported
8.2.3
SDRAM Controller
• Supported devices
– Standard and Low-power SDRAM (Mobile SDRAM)
• 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
25
6249B–ATARM–14-Dec-06
• Energy-saving capabilities
– Self-refresh, power down and deep power down modes supported
• Error detection
– Refresh Error Interrupt
• SDRAM Power-up Initialization by software
• CAS Latency of 1, 2 and 3 supported
• Auto Precharge Command not used
8.2.4
Error Corrected Code Controller
• Tracking the accesses to a NAND Flash device by trigging on the corresponding chip select
• Single-bit error correction and two-bit random detection
• Automatic Hamming Code Calculation while writing
– ECC value available in a register
• Automatic Hamming Code Calculation while reading
– Error Report, including error flag, correctable error flag and word address being
detected erroneous
– Support 8- or 16-bit NAND Flash devices with 512-, 1024-, 2048- or 4096-byte
pages
9. System Controller
The System Controller is a set of peripherals that allow handling of key elements of the system,
such as power, resets, clocks, time, interrupts, watchdog, etc.
The System Controller User Interface also embeds registers that are used to configure the Bus
Matrix and a set of registers for the chip configuration. The chip configuration registers can be
used to configure:
– EBI0 and EBI1 chip select assignment and voltage range for external memories
– ARM Processor Tightly Coupled Memories
The System Controller peripherals are all mapped within the highest 16 Kbytes of address
space, between addresses 0xFFFF C000 and 0xFFFF FFFF.
However, all the registers of the System Controller are mapped on the top of the address space.
This allows all the registers of the System Controller to be addressed from a single pointer by
using the standard ARM instruction set, as the Load/Store instructions have an indexing mode of
± 4 Kbytes.
Figure 9-1 on page 27 shows the System Controller block diagram.
Figure 8-1 on page 20 shows the mapping of the User Interfaces of the System Controller
peripherals.
26
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
9.1
System Controller Block Diagram
Figure 9-1.
AT91SAM9263 System Controller Block Diagram
System Controller
VDDCORE Powered
irq0-irq1
fiq
nirq
nfiq
Advanced
Interrupt
Controller
periph_irq[2..29]
pit_irq
rtt0_irq
rtt1_irq
wdt_irq
dbgu_irq
pmc_irq
rstc_irq
MCK
periph_nreset
int
MCK
debug
periph_nreset
PCK
dbgu_txd
debug
Periodic
Interval
Timer
pit_irq
Watchdog
Timer
wdt_irq
jtag_nreset
SLCK
debug
idle
proc_nreset
NRST
periph_nreset
VDDCORE
Reset
Controller
periph_nreset
proc_nreset
backup_nreset
battery_save
VDDBU
VDDBU
POR
VDDBU Powered
SLCK
SLCK
backup_nreset
SLCK
backup_nreset
Real-Time
Timer 0
rtt0_irq
Real-Time
Timer 1
rtt1_irq
rtt0_alarm
rtt1_alarm
WKUP
Voltage
Controller
USB
Device
Port
battery_save
UHPCK
backup_nreset
rtt0_alarm
rtt1_alarm
20 General-Purpose
Backup Registers
SLCK
periph_clk[2..29]
pck[0-3]
int
MAINCK
XOUT
MAIN
OSC
PLLRCA
PLLA
PLLACK
PLLB
periph_nreset
periph_irq[24]
Shut-Down
Controller
SLOW
CLOCK
OSC
UDPCK
periph_clk[24]
SLCK
SHDN
PLLRCB
Bus Matrix
rstc_irq
por_ntrst
jtag_nreset
VDDCORE
POR
XIN
Boundary Scan
TAP Controller
MCK
wdt_fault
WDRPROC
XOUT32
ARM926EJ-S
proc_nreset
dbgu_irq
Debug
Unit
dbgu_rxd
XIN32
ntrst
por_ntrst
Power
Management
Controller
PCK
OTGCK
UDPCK
periph_clk[29]
periph_nreset
USB Host
Port
periph_irq[29]
periph_clk[26]
periph_nreset
LCD
Controller
periph_irq[26]
MCK
PLLBCK
pmc_irq
periph_nreset
periph_clk[7..27]
idle
periph_nreset
periph_nreset
periph_clk[2..6]
dbgu_rxd
PA0-PA31
PB0-PB31
PC0-PC31
PD0-PD31
PIO
Controllers
periph_irq[2..6]
irq0-irq1
fiq
dbgu_txd
Embedded
Peripherals
periph_irq[7..27]
in
out
enable
PE0-PE31
27
6249B–ATARM–14-Dec-06
9.2
Reset Controller
• Based on two Power-on-Reset cells
– One on VDDBU and one on VDDCORE
• Status of the last reset
– Either general reset (VDDBU rising), wake-up reset (VDDCORE rising), software
reset, user reset or watchdog reset
• Controls the internal resets and the NRST pin output
– Allows shaping a reset signal for the external devices
9.3
Shutdown Controller
• Shutdown and Wake-up logic
– Software programmable assertion of the SHDN open-drain pin
– Deassertion programmable on a WKUP pin level change or on alarm
9.4
Clock Generator
• Embeds the low-power 32768 Hz Slow Clock Oscillator
– Provides the permanent Slow Clock SLCK to the system
• Embeds the Main Oscillator
– Oscillator bypass feature
– Supports 3 to 20 MHz crystals
• Embeds 2 PLLs
– Output 80 to 240 MHz clocks
– Integrates an input divider to increase output accuracy
– 1 MHz Minimum input frequency
Figure 9-2.
Clock Generator Block Diagram
Clock Generator
XIN32
Slow Clock
Oscillator
Slow Clock
SLCK
Main
Oscillator
Main Clock
MAINCK
PLLRCA
PLL and
Divider A
PLLA Clock
PLLACK
PLLRCB
PLL and
Divider B
PLLB Clock
PLLBCK
XOUT32
XIN
XOUT
Status
Control
Power
Management
Controller
28
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
9.5
Power Management Controller
• Provides:
– the Processor Clock PCK
– the Master Clock MCK, in particular to the Matrix and the memory interfaces
– the USB Device Clock UDPCK
– the USB Host Clock UHPCK
– independent peripheral clocks, typically at the frequency of MCK
– four programmable clock outputs: PCK0 to PCK3
• Five flexible operating modes:
– Normal Mode with processor and peripherals running at a programmable frequency
– Idle Mode with processor stopped while waiting for an interrupt
– Slow Clock Mode with processor and peripherals running at low frequency
– Standby Mode, mix of Idle and Backup Mode, with peripherals running at low
frequency, processor stopped waiting for an interrupt
– Backup Mode with Main Power Supplies off, VDDBU powered by a battery
Figure 9-3.
AT91SAM9263 Power Management Controller Block Diagram
Processor
Clock
Controller
int
Master Clock Controller
SLCK
MAINCK
PLLACK
PLLBCK
Prescaler
/1,/2,/4,...,/64
PCK
Idle Mode
Divider
/1,/2,/3,/4
MCK
Peripherals
Clock Controller
periph_clk[..]
ON/OFF
Programmable Clock Controller
SLCK
MAINCK
PLLACK
PLLBCK
ON/OFF
Prescaler
/1,/2,/4,...,/64
pck[..]
USB Clock Controller
PLLBCK
Divider
/1,/2,/4
ON/OFF
UDPCK
UHPCK
9.6
Periodic Interval Timer
• Includes a 20-bit Periodic Counter, with less than 1 µs accuracy
• Includes a 12-bit Interval Overlay Counter
• Real-time OS or Linux®/WindowsCE® compliant tick generator
9.7
Watchdog Timer
• 16-bit key-protected Counter, programmable only once
29
6249B–ATARM–14-Dec-06
• Windowed, prevents the processor deadlocking on the watchdog access
9.8
Real-time Timer
• Two Real-time Timers, allowing backup of time with different accuracies
– 32-bit Free-running back-up counter
– Integrates a 16-bit programmable prescaler running on the embedded 32.768Hz
oscillator
– Alarm Register capable of generating a wake-up of the system through the
Shutdown Controller
9.9
General-purpose Backup Registers
• Twenty 32-bit general-purpose backup registers
9.10
Backup Power Switch
• Automatic switch of VDDBU to VDDCORE guaranteeing very low power consumption on
VDDBU while VDDCORE is present
9.11
Advanced Interrupt Controller
• Controls the interrupt lines (nIRQ and nFIQ) of the 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 (PIT, RTT, PMC, DBGU, etc.)
– Programmable Edge-triggered or Level-sensitive Internal Sources
– Programmable Positive/Negative Edge-triggered or High/Low Level-sensitive
• Four External Sources plus the Fast Interrupt signal
• 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 models are
enabled
• Fast Forcing
– Permits redirecting any normal interrupt source on the Fast Interrupt of the
processor
9.12
Debug Unit
• Composed of two functions
– Two-pin UART
30
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
– Debug Communication Channel (DCC) support
• 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
– Support for two PDC channels with connection to receiver and transmitter
• Debug Communication Channel Support
– Offers visibility of and interrupt trigger from COMMRX and COMMTX signals from
the ARM Processor’s ICE Interface
9.13
Chip Identification
• Chip ID: 0x019607A0
• JTAG ID: 0x05B0C03F
• ARM926 TAP ID: 0x0792603F
9.14
PIO Controllers
• Five PIO Controllers, PIOA to PIOE, controlling a total of 160 I/O Lines
• Each PIO Controller controls up to 32 programmable I/O Lines
– PIOA has 32 I/O Lines
– PIOB has 32 I/O Lines
– PIOC has 32 I/O Lines
– PIOD has 32 I/O Lines
– PIOE has 32 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
31
6249B–ATARM–14-Dec-06
10. Peripherals
10.1
User Interface
The Peripherals are mapped in the upper 256 Mbytes of the address space between the
addresses 0xFFFA 0000 and 0xFFFC FFFF. Each User Peripheral is allocated 16 Kbytes of
address space.
A complete memory map is presented in Figure 8-1 on page 20.
10.2
Identifiers
Table 10-1 defines the Peripheral Identifiers. 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 ID
Peripheral Mnemonic
Peripheral Name
External Interrupt
0
AIC
Advanced Interrupt Controller
FIQ
1
SYSC
System Controller Interrupt
2
PIOA
Parallel I/O Controller A
Note:
32
AT91SAM9263 Peripheral Identifiers
3
PIOB
Parallel I/O Controller B
4
PIOC to PIOE
Parallel I/O Controller C, D and E
5
reserved
6
reserved
7
US0
USART 0
8
US1
USART 1
9
US2
USART 2
10
MCI0
Multimedia Card Interface 0
11
MCI1
Multimedia Card Interface 1
12
CAN
CAN Controller
13
TWI
Two-Wire Interface
14
SPI0
Serial Peripheral Interface 0
15
SPI1
Serial Peripheral Interface 1
16
SSC0
Synchronous Serial Controller 0
17
SSC1
Synchronous Serial Controller 1
18
AC97C
AC97 Controller
19
TC0, TC1, TC2
Timer/Counter 0, 1 and 2
20
PWMC
Pulse Width Modulation Controller
21
EMAC
Ethernet MAC
22
reserved
23
2DGE
24
UDP
USB Device Port
25
ISI
Image Sensor Interface
26
LCDC
LCD Controller
27
DMA
DMA Controller
28
reserved
29
UHP
USB Host Port
30
AIC
Advanced Interrupt Controller
IRQ0
31
AIC
Advanced Interrupt Controller
IRQ1
2D Graphic Engine
Setting AIC, SYSC, UHP and IRQ0 - 1 bits in the clock set/clear registers of the PMC has no effect.
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
10.2.1
Peripheral Interrupts and Clock Control
10.2.1.1
System Interrupt
The System Interrupt in Source 1 is the wired-OR of the interrupt signals coming from:
• the SDRAM Controller
• the Debug Unit
• the Periodic Interval Timer
• the Real-Time Timer
• the Watchdog Timer
• the Reset Controller
• the Power Management Controller
The clock of these peripherals cannot be deactivated and Peripheral ID 1 can only be used
within the Advanced Interrupt Controller.
10.2.1.2
External Interrupts
All external interrupt signals, i.e., the Fast Interrupt signal FIQ or the Interrupt signals IRQ0 to
IRQ1, use a dedicated Peripheral ID. However, there is no clock control associated with these
peripheral IDs.
10.2.1.3
Timer Counter Interrupts
The three Timer Counter channels interrupt signals are OR-wired together to provide the interrupt source 19 of the Advanced Interrupt Controller. This forces the programmer to read all
Timer Counter status registers before branching the right Interrupt Service Routine.
The Timer Counter channels clocks cannot be deactivated independently. Switching off the
clock of the Peripheral 19 disables the clock of the 3 channels.
10.3
Peripherals Signals Multiplexing on I/O Lines
The AT91SAM9263 device features 5 PIO controllers, PIOA, PIOB, PIOC, PIOD and PIOE,
which multiplex the I/O lines of the peripheral set.
Each PIO Controller controls up to 32 lines. Each line can be assigned to one of two peripheral
functions, A or B. The multiplexing tables define how the I/O lines of the peripherals A and B are
multiplexed on the PIO Controllers. The two columns “Function” and “Comments” have been
inserted in this table for the user’s own comments; they may be used to track how pins are
defined in an application.
Note that some peripheral functions which are output only may be duplicated within both tables.
The column “Reset State” indicates whether the PIO Line resets in I/O mode or in peripheral
mode. If I/O is specified, 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 reset is released. 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 specified 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 of pins controlling memories,
in particular the address lines, which require the pin to be driven as soon as the reset is
released. Note that the pull-up resistor is also enabled in this case.
33
6249B–ATARM–14-Dec-06
10.3.1
PIO Controller A Multiplexing
Table 10-2.
Multiplexing on PIO Controller A
PIO Controller A
Application Usage
I/O Line
Peripheral A
Peripheral B
Reset
State
Power
Supply
PA0
MCI0_DA0
SPI0_MISO
I/O
VDDIOP0
PA1
MCI0_CDA
SPI0_MOSI
I/O
VDDIOP0
SPI0_SPCK
I/O
VDDIOP0
PA2
PA3
MCI0_DA1
SPI0_NPCS1
I/O
VDDIOP0
PA4
MCI0_DA2
SPI0_NPCS2
I/O
VDDIOP0
PA5
MCI0_DA3
SPI0_NPCS0
I/O
VDDIOP0
PA6
MCI1_CK
PCK2
I/O
VDDIOP0
PA7
MCI1_CDA
I/O
VDDIOP0
PA8
MCI1_DA0
I/O
VDDIOP0
PA9
MCI1_DA1
I/O
VDDIOP0
PA10
MCI1_DA2
I/O
VDDIOP0
PA11
MCI1_DA3
I/O
VDDIOP0
PA12
MCI0_CK
I/O
VDDIOP0
PA13
CANTX
PCK0
I/O
VDDIOP0
PA14
CANRX
IRQ0
I/O
VDDIOP0
PA15
TCLK2
IRQ1
I/O
VDDIOP0
PA16
MCI0_CDB
EBI1_D16
I/O
VDDIOM1
PA17
MCI0_DB0
EBI1_D17
I/O
VDDIOM1
PA18
MCI0_DB1
EBI1_D18
I/O
VDDIOM1
PA19
MCI0_DB2
EBI1_D19
I/O
VDDIOM1
PA20
MCI0_DB3
EBI1_D20
I/O
VDDIOM1
PA21
MCI1_CDB
EBI1_D21
I/O
VDDIOM1
PA22
MCI1_DB0
EBI1_D22
I/O
VDDIOM1
PA23
MCI1_DB1
EBI1_D23
I/O
VDDIOM1
PA24
MCI1_DB2
EBI1_D24
I/O
VDDIOM1
PA25
MCI1_DB3
EBI1_D25
I/O
VDDIOM1
PA26
TXD0
EBI1_D26
I/O
VDDIOM1
PA27
RXD0
EBI1_D27
I/O
VDDIOM1
PA28
RTS0
EBI1_D28
I/O
VDDIOM1
PA29
CTS0
EBI1_D29
I/O
VDDIOM1
PA30
SCK0
EBI1_D30
I/O
VDDIOM1
PA31
DMARQ0
EBI1_D31
I/O
VDDIOM1
34
Function
Comments
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
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
Power
Supply
PB0
AC97FS
TF0
I/O
VDDIOP0
PB1
AC97CK
TK0
I/O
VDDIOP0
PB2
AC97TX
TD0
I/O
VDDIOP0
PB3
AC97RX
RD0
I/O
VDDIOP0
PB4
TWD
RK0
I/O
VDDIOP0
PB5
TWCK
RF0
I/O
VDDIOP0
PB6
TF1
DMARQ1
I/O
VDDIOP0
PB7
TK1
PWM0
I/O
VDDIOP0
PB8
TD1
PWM1
I/O
VDDIOP0
PB9
RD1
LCDCC
I/O
VDDIOP0
PB10
RK1
PCK1
I/O
VDDIOP0
PB11
RF1
SPI0_NPCS3
I/O
VDDIOP0
PB12
SPI1_MISO
I/O
VDDIOP0
PB13
SPI1_MOSI
I/O
VDDIOP0
PB14
SPI1_SPCK
I/O
VDDIOP0
PB15
SPI1_NPCS0
I/O
VDDIOP0
PB16
SPI1_NPCS1
PCK1
I/O
VDDIOP0
PB17
SPI1_NPCS2
TIOA2
I/O
VDDIOP0
PB18
SPI1_NPCS3
TIOB2
I/O
VDDIOP0
PB19
I/O
VDDIOP0
PB20
I/O
VDDIOP0
PB21
I/O
VDDIOP0
PB22
I/O
VDDIOP0
PB23
I/O
VDDIOP0
I/O
VDDIOP0
PB25
I/O
VDDIOP0
PB26
I/O
VDDIOP0
PB24
DMARQ3
PB27
PWM2
I/O
VDDIOP0
PB28
TCLK0
I/O
VDDIOP0
PB29
PWM3
I/O
VDDIOP0
PB30
I/O
VDDIOP0
PB31
I/O
VDDIOP0
Function
Comments
35
6249B–ATARM–14-Dec-06
10.3.3
PIO Controller C Multiplexing
Table 10-4.
Multiplexing on PIO Controller C
PIO Controller C
Application Usage
Reset
State
Power
Supply
LCDVSYNC
I/O
VDDIOP0
PC1
LCDHSYNC
I/O
VDDIOP0
PC2
LCDDOTCK
I/O
VDDIOP0
PC3
LCDDEN
PWM1
I/O
VDDIOP0
PC4
LCDD0
LCDD3
I/O
VDDIOP0
PC5
LCDD1
LCDD4
I/O
VDDIOP0
PC6
LCDD2
LCDD5
I/O
VDDIOP0
PC7
LCDD3
LCDD6
I/O
VDDIOP0
PC8
LCDD4
LCDD7
I/O
VDDIOP0
PC9
LCDD5
LCDD10
I/O
VDDIOP0
PC10
LCDD6
LCDD11
I/O
VDDIOP0
PC11
LCDD7
LCDD12
I/O
VDDIOP0
PC12
LCDD8
LCDD13
I/O
VDDIOP0
PC13
LCDD9
LCDD14
I/O
VDDIOP0
PC14
LCDD10
LCDD15
I/O
VDDIOP0
PC15
LCDD11
LCDD19
I/O
VDDIOP0
PC16
LCDD12
LCDD20
I/O
VDDIOP0
PC17
LCDD13
LCDD21
I/O
VDDIOP0
PC18
LCDD14
LCDD22
I/O
VDDIOP0
PC19
LCDD15
LCDD23
I/O
VDDIOP0
PC20
LCDD16
ETX2
I/O
VDDIOP0
PC21
LCDD17
ETX3
I/O
VDDIOP0
PC22
LCDD18
ERX2
I/O
VDDIOP0
PC23
LCDD19
ERX3
I/O
VDDIOP0
PC24
LCDD20
ETXER
I/O
VDDIOP0
PC25
LCDD21
ERXDV
I/O
VDDIOP0
PC26
LCDD22
ECOL
I/O
VDDIOP0
PC27
LCDD23
ERXCK
I/O
VDDIOP0
PC28
PWM0
TCLK1
I/O
VDDIOP0
PC29
PCK0
PWM2
I/O
VDDIOP0
PC30
DRXD
I/O
VDDIOP0
PC31
DTXD
I/O
VDDIOP0
I/O Line
Peripheral A
PC0
36
Peripheral B
Function
Comments
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
10.3.4
PIO Controller D Multiplexing
Table 10-5.
Multiplexing on PIO Controller D
PIO Controller D
Application Usage
I/O Line
Peripheral A
Peripheral B
Reset
State
Power
Supply
PD0
TXD1
SPI0_NPCS2
I/O
VDDIOP0
PD1
RXD1
SPI0_NPCS3
I/O
VDDIOP0
PD2
TXD2
SPI1_NPCS2
I/O
VDDIOP0
PD3
RXD2
SPI1_NPCS3
I/O
VDDIOP0
PD4
FIQ
DMARQ2
I/O
VDDIOP0
PD5
EBI0_NWAIT
RTS2
I/O
VDDIOM0
PD6
EBI0_NCS4/CFCS0
CTS2
I/O
VDDIOM0
PD7
EBI0_NCS5/CFCS1
RTS1
I/O
VDDIOM0
PD8
EBI0_CFCE1
CTS1
I/O
VDDIOM0
PD9
EBI0_CFCE2
SCK2
I/O
VDDIOM0
SCK1
I/O
VDDIOM0
PD10
PD11
EBI0_NCS2
TSYNC
I/O
VDDIOM0
PD12
EBI0_A23
TCLK
A23
VDDIOM0
PD13
EBI0_A24
TPS0
A24
VDDIOM0
PD14
EBI0_A25_CFRNW
TPS1
A25
VDDIOM0
PD15
EBI0_NCS3/NANDCS
TPS2
I/O
VDDIOM0
PD16
EBI0_D16
TPK0
I/O
VDDIOM0
PD17
EBI0_D17
TPK1
I/O
VDDIOM0
PD18
EBI0_D18
TPK2
I/O
VDDIOM0
PD19
EBI0_D19
TPK3
I/O
VDDIOM0
PD20
EBI0_D20
TPK4
I/O
VDDIOM0
PD21
EBI0_D21
TPK5
I/O
VDDIOM0
PD22
EBI0_D22
TPK6
I/O
VDDIOM0
PD23
EBI0_D23
TPK7
I/O
VDDIOM0
PD24
EBI0_D24
TPK8
I/O
VDDIOM0
PD25
EBI0_D25
TPK9
I/O
VDDIOM0
PD26
EBI0_D26
TPK10
I/O
VDDIOM0
PD27
EBI0_D27
TPK11
I/O
VDDIOM0
PD28
EBI0_D28
TPK12
I/O
VDDIOM0
PD29
EBI0_D29
TPK13
I/O
VDDIOM0
PD30
EBI0_D30
TPK14
I/O
VDDIOM0
PD31
EBI0_D31
TPK15
I/O
VDDIOM0
Function
Comments
37
6249B–ATARM–14-Dec-06
10.3.5
PIO Controller E Multiplexing
Table 10-6.
Multiplexing on PIO Controller E
PIO Controller E
Application Usage
Reset
State
Power
Supply
ISI_D0
I/O
VDDIOP1
PE1
ISI_D1
I/O
VDDIOP1
PE2
ISI_D2
I/O
VDDIOP1
PE3
ISI_D3
I/O
VDDIOP1
PE4
ISI_D4
I/O
VDDIOP1
PE5
ISI_D5
I/O
VDDIOP1
PE6
ISI_D6
I/O
VDDIOP1
PE7
ISI_D7
I/O
VDDIOP1
PE8
ISI_PCK
TIOA1
I/O
VDDIOP1
PE9
ISI_HSYNC
TIOB1
I/O
VDDIOP1
PE10
ISI_VSYNC
PWM3
I/O
VDDIOP1
PE11
ISI_MCK
PCK3
I/O
VDDIOP1
PE12
ISI_D8
I/O
VDDIOP1
PE13
ISI_D9
I/O
VDDIOP1
PE14
ISI_D10
I/O
VDDIOP1
PE15
ISI_D11
I/O
VDDIOP1
PE16
I/O
VDDIOP1
PE17
I/O
VDDIOP1
I/O Line
Peripheral A
PE0
Peripheral B
PE18
TIOA0
I/O
VDDIOP1
PE19
TIOB0
I/O
VDDIOP1
PE20
EBI1_NWAIT
I/O
VDDIOM1
PE21
ETXCK
EBI1_NANDWE
I/O
VDDIOM1
PE22
ECRS
EBI1_NCS2/NANDCS
I/O
VDDIOM1
PE23
ETX0
EB1_NANDOE
I/O
VDDIOM1
PE24
ETX1
EBI1_NWR3/NBS3
I/O
VDDIOM1
PE25
ERX0
EBI1_NCS1/SDCS
I/O
VDDIOM1
PE26
ERX1
I/O
VDDIOM1
PE27
ERXER
EBI1_SDCKE
I/O
VDDIOM1
PE28
ETXEN
EBI1_RAS
I/O
VDDIOM1
PE29
EMDC
EBI1_CAS
I/O
VDDIOM1
PE30
EMDIO
EBI1_SDWE
I/O
VDDIOM1
PE31
EF100
EBI1_SDA10
I/O
VDDIOM1
38
Function
Comments
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
10.4
10.4.1
System Resource Multiplexing
LCD Controller
The LCD Controller can interface with several LCD panels. It supports 4 bits per pixel (bpp), 8
bpp or 16 bpp without limitation. Interfacing 24 bpp TFT panels prevents using the Ethernet
MAC. 16 bpp TFT panels are interfaced through peripheral B functions, as color data is output
on LCDD3 to LCDD7, LCDD11 to LCDD15 and LCDD19 to LCDD23. Intensity bit is output on
LCDD10. Using the peripheral B does not prevent using MAC lines. 16 bpp STN panels are
interfaced through peripheral A and color data is output on LCDD0 to LCDD15, thus MAC lines
can be used on peripheral B.
Mapping the LCD signals on peripheral A and peripheral B makes is possible to use 24 bpp TFT
panels in 24 bits (peripheral A) or 16 bits (peripheral B) by reprogramming the PIO controller and
thus without hardware modification.
10.4.2
ETM™
Using the ETM prevents the use of the EBI0 in 32-bit mode. Only 16-bit mode (EBI0_D0 to
EBI0_D15) is available, makes EBI0 unable to interface CompactFlash and NandFlash cards,
reduces EBI0’s address bus width which makes it unable to address memory ranges bigger than
0x7FFFFF and finally it makes impossible to use EBI0_NCS2.
10.4.3
EBI1
Using the following features prevents using EBI1 in 32-bit mode:
• the second slots of MCI0 and/or MCI1
• USART0
• DMA request 0 (DMARQ0)
10.4.4
SSC
Using SSC0 prevents using the AC97 Controller and Two-wire Interface.
Using SSC1 prevents using DMA Request 1, PWM0, PWM1, LCDCC and PCK1.
10.4.5
USART
Using USART2 prevents using EBI0’s NWAIT signal, Chip Select 4 and CompactFlash Chip
Enable 2.
Using USART1 prevents using EBI0’s Chip Select 5 and CompactFlash Chip Enable1.
10.4.6
NAND Flash
Using the NAND Flash interface prevents using NCS3, NCS6 and NCS7 to access other parallel
devices.
10.4.7
CompactFlash
Using the CompactFlash interface prevents using NCS4 and/or NCS5 to access other parallel
devices.
10.4.8
SPI0 and MCI Interface
SPI0 signals and MCI0 signals are multiplexed, as the DataFlash Card is hardware-compatible
with the SDCard. Only one can be used at a time.
39
6249B–ATARM–14-Dec-06
10.4.9
Interrupts
Using IRQ0 prevents using the CAN controller.
Using FIQ prevents using DMA Request 2.
10.4.10
Image Sensor Interface
Using ISI in 8-bit data mode prevents using timers TIOA1, TIOB1.
Using ISI in extended mode (up to 12 bits) prevents using keyboard row lines.
10.4.11
Timers
Using TC0 prevents using columns 1 and 2 of the Keyboard Interface.
Using TIOA2 and TIOB2, in this order, prevents using SPI1’s Chip Selects [2-3].
10.5
10.5.1
Embedded Peripherals Overview
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
• Very fast transfers supported
– Transfers with baud rates up to MCK
– The chip select line may be left active to speed up transfers on the same device
10.5.2
Two-wire Interface
• Master Mode only
• Compatibility with standard two-wire serial memory
• One, two or three bytes for slave address
• Sequential read/write operations
10.5.3
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
40
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
– 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
– Hardware handshaking RTS-CTS
– Receiver time-out and transmitter timeguard
– Optional Multi-drop Mode with address generation and detection
– Optional Manchester Encoding
• 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
10.5.4
Serial Synchronous Controller
• Provides serial synchronous communication links used in audio and telecom applications
(with CODECs in Master or Slave Modes, I2S, TDM Buses, Magnetic Card Reader, etc.)
• Contains an independent receiver and transmitter and a common clock divider
• 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
10.5.5
AC97 Controller
• Compatible with AC97 Component Specification V2.2
• Can interface with a single analog front end
• Three independent RX Channels and three independent TX Channels
– One RX and one TX channel dedicated to the AC97 analog front end control
– One RX and one TX channel for data transfers, associated with a PDC
– One RX and one TX channel for data transfers with no PDC
• Time Slot Assigner that can assign up to 12 time slots to a channel
• Channels support mono or stereo up to 20-bit sample length
– Variable sampling rate AC97 Codec Interface (48 kHz and below)
10.5.6
Timer Counter
• Three 16-bit Timer Counter Channels
• Wide range of functions including:
– Frequency Measurement
41
6249B–ATARM–14-Dec-06
– 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
• Two global registers that act on all three TC Channels
10.5.7
Pulse Width Modulation Controller
• 4 channels, one 16-bit counter per channel
• Common clock generator, providing thirteen different clocks
– Modulo n counter providing eleven clocks
– Two independent Linear Dividers working on modulo n counter outputs
• Independent channel programming
– Independent Enable Disable commands
– Independent clock selection
– Independent period and duty cycle, with double bufferization
– Programmable selection of the output waveform polarity
– Programmable center or left aligned output waveform
10.5.8
Multimedia Card Interface
• Two double-channel Multimedia Card Interfaces, allowing concurrent transfers with 2 cards
• Compatibility with MultiMediaCard Specification Version 2.2
• Compatibility with SD Memory Card Specification Version 1.0
• Compatibility with SDIO Specification Version V1.0.
• Cards clock rate up to Master Clock divided by 2
• Embedded power management to slow down clock rate when not used
• Each MCI has two slots, each supporting
– One slot for one MultiMediaCard bus (up to 30 cards) or
– One SD Memory Card
• Support for stream, block and multi-block data read and write
10.5.9
CAN Controller
• Fully compliant with 16-mailbox CAN 2.0A and 2.0B CAN Controllers
• Bit rates up to 1Mbit/s.
• Object-oriented mailboxes, each with the following properties:
– CAN Specification 2.0 Part A or 2.0 Part B programmable for each message
– Object Configurable as receive (with overwrite or not) or transmit
42
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
– Local Tag and Mask Filters up to 29-bit Identifier/Channel
– 32 bits access to Data registers for each mailbox data object
– Uses a 16-bit time stamp on receive and transmit message
– Hardware concatenation of ID unmasked bitfields to speedup family ID processing
– 16-bit internal timer for Time Stamping and Network synchronization
– Programmable reception buffer length up to 16 mailbox object
– Priority Management between transmission mailboxes
– Autobaud and listening mode
– Low power mode and programmable wake-up on bus activity or by the application
– Data, Remote, Error and Overload Frame handling
10.5.10
USB Host Port
• Compliant with Open HCI Rev 1.0 Specification
• Compliant with USB V2.0 full-speed and low-speed specification
• Supports both low-speed 1.5 Mbps and full-speed 12 Mbps devices
• Root hub integrated with two downstream USB ports
• Two embedded USB transceivers
• Supports power management
• Operates as a master on the matrix
10.5.11
USB Device Port
• USB V2.0 full-speed compliant, 12 Mbits per second
• Embedded USB V2.0 full-speed transceiver
• Embedded 2,432-byte 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 and 3: 64 bytes, no ping-pong mode
– Endpoint 1 and 2: 64 bytes, ping-pong mode
– Endpoint 4 and 5: 512 bytes, ping-pong mode
10.5.12
LCD Controller
• Single and Dual scan color and monochrome passive STN LCD panels supported
• Single scan active TFT LCD panels supported
• 4-bit single scan, 8-bit single or dual scan, 16-bit dual scan STN interfaces supported
• Up to 24-bit single scan TFT interfaces supported
• Up to 16 gray levels for mono STN and up to 4096 colors for color STN displays
• 1, 2 bits per pixel (palletized), 4 bits per pixel (non-palletized) for mono STN
• 1, 2, 4, 8 bits per pixel (palletized), 16 bits per pixel (non-palletized) for color STN
• 1, 2, 4, 8 bits per pixel (palletized), 16, 24 bits per pixel (non-palletized) for TFT
• Single clock domain architecture
• Resolution supported up to 2048x2048
43
6249B–ATARM–14-Dec-06
• 2D DMA Controller for management of virtual Frame Buffer
– Allows management of frame buffer larger than the screen size and moving the view
over this virtual frame buffer
• Automatic resynchronization of the frame buffer pointer to prevent flickering
10.5.13
2D Graphics Controller
• Acts as one Matrix Master
• Commands are passed through the APB User Interface
• Operates directly in the frame buffer of the LCD Controller
– Line draw
– Block transfer
– Polygon fill
– Clipping
• Commands queuing through a FIFO
10.5.14
Ethernet 10/100 MAC
• Compatibility with IEEE Standard 802.3
• 10 and 100 Mbits per second data throughput capability
• Full- and half-duplex operations
• MII or RMII interface to the physical layer
• Register Interface to address, data, 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
• Support promiscuous mode where all valid frames are copied to memory
• Support physical layer management through MDIO interface control of alarm and update
time/calendar data in
10.5.15
Image Sensor Interface
• ITU-R BT. 601/656 8-bit mode external interface support
• Support for ITU-R BT.656-4 SAV and EAV synchronization
• Vertical and horizontal resolutions up to 2048 x 2048
• Preview Path up to 640*480
• Support for packed data formatting for YCbCr 4:2:2 formats
• Preview scaler to generate smaller size image
• Programmable frame capture rate
44
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
11. ARM926EJ-S Processor Overview
11.1
Overview
The ARM926EJ-S processor is a member of the ARM9s family of general-purpose microprocessors. The ARM926EJ-S implements ARM architecture version 5TEJ and is targeted at
multi-tasking applications where full memory management, high performance, low die size
and low power are all important features.
The ARM926EJ-S processor supports the 32-bit ARM and 16-bit THUMB instruction sets,
enabling the user to trade off between high performance and high code density. It also supports 8-bit Java instruction set and includes features for efficient execution of Java bytecode,
providing a Java performance similar to a JIT (Just-In-Time compilers), for the next generation
of Java-powered wireless and embedded devices. It includes an enhanced multiplier design
for improved DSP performance.
The ARM926EJ-S processor supports the ARM debug architecture and includes logic to assist
in both hardware and software debug.
The ARM926EJ-S provides a complete high performance processor subsystem, including:
• an ARM9EJ-S™ integer core
• a Memory Management Unit (MMU)
• separate instruction and data AMBA™ AHB bus interfaces
• separate instruction and data TCM interfaces
45
6249B–ATARM–14-Dec-06
11.2
Block Diagram
Figure 11-1. ARM926EJ-S Internal Functional Block Diagram
ARM926EJ-S
TCM
Interface
Coprocessor
Interface
ETM
Interface
DEXT
Droute
Data
AHB
Interface
AHB
DCACHE
WDATA
Bus
Interface
Unit
RDATA
ARM9EJ-S
DA
MMU
EmbeddedICE
-RT
Processor
Instruction
AHB
Interface
IA
AHB
INSTR
ICE
Interface
ICACHE
Iroute
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11.3
11.3.1
ARM9EJ-S Processor
ARM9EJ-S™ Operating States
The ARM9EJ-S processor can operate in three different states, each with a specific instruction
set:
• ARM state: 32-bit, word-aligned ARM instructions.
• THUMB state: 16-bit, halfword-aligned Thumb instructions.
• Jazelle state: variable length, byte-aligned Jazelle instructions.
In Jazelle state, all instruction Fetches are in words.
11.3.2
Switching State
The operating state of the ARM9EJ-S core can be switched between:
• ARM state and THUMB state using the BX and BLX instructions, and loads to the PC
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• ARM state and Jazelle state using the BXJ instruction
All exceptions are entered, handled and exited in ARM state. If an exception occurs in Thumb
or Jazelle states, the processor reverts to ARM state. The transition back to Thumb or Jazelle
states occurs automatically on return from the exception handler.
11.3.3
Instruction Pipelines
The ARM9EJ-S core uses two kinds of pipelines to increase the speed of the flow of instructions to the processor.
A five-stage (five clock cycles) pipeline is used for ARM and Thumb states. It consists of
Fetch, Decode, Execute, Memory and Writeback stages.
A six-stage (six clock cycles) pipeline is used for Jazelle state It consists of Fetch,
Jazelle/Decode (two clock cycles), Execute, Memory and Writeback stages.
11.3.4
Memory Access
The ARM9EJ-S core supports byte (8-bit), half-word (16-bit) and word (32-bit) access. Words
must be aligned to four-byte boundaries, half-words must be aligned to two-byte boundaries
and bytes can be placed on any byte boundary.
Because of the nature of the pipelines, it is possible for a value to be required for use before it
has been placed in the register bank by the actions of an earlier instruction. The ARM9EJ-S
control logic automatically detects these cases and stalls the core or forward data.
11.3.5
Jazelle Technology
The Jazelle technology enables direct and efficient execution of Java byte codes on ARM processors, providing high performance for the next generation of Java-powered wireless and
embedded devices.
The new Java feature of ARM9EJ-S can be described as a hardware emulation of a JVM
(Java Virtual Machine). Java mode will appear as another state: instead of executing ARM or
Thumb instructions, it executes Java byte codes. The Java byte code decoder logic implemented in ARM9EJ-S decodes 95% of executed byte codes and turns them into ARM
instructions without any overhead, while less frequently used byte codes are broken down into
optimized sequences of ARM instructions. The hardware/software split is invisible to the programmer, invisible to the application and invisible to the operating system. All existing ARM
registers are re-used in Jazelle state and all registers then have particular functions in this
mode.
Minimum interrupt latency is maintained across both ARM state and Java state. Since byte
codes execution can be restarted, an interrupt automatically triggers the core to switch from
Java state to ARM state for the execution of the interrupt handler. This means that no special
provision has to be made for handling interrupts while executing byte codes, whether in hardware or in software.
11.3.6
ARM9EJ-S Operating Modes
In all states, there are seven operation modes:
• User mode is the usual ARM program execution state. It is used for executing most
application programs
• Fast Interrupt (FIQ) mode is used for handling fast interrupts. It is suitable for high-speed
data transfer or channel process
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• Interrupt (IRQ) mode is used for general-purpose interrupt handling
• Supervisor mode is a protected mode for the operating system
• Abort mode is entered after a data or instruction prefetch abort
• System mode is a privileged user mode for the operating system
• Undefined mode is entered when an undefined instruction exception occurs
Mode changes may be made under software control, or may be brought about by external
interrupts or exception processing. Most application programs execute in User Mode. The
non-user modes, known as privileged modes, are entered in order to service interrupts or
exceptions or to access protected resources.
11.3.7
ARM9EJ-S Registers
The ARM9EJ-S core has a total of 37 registers:
• 31 general-purpose 32-bit registers
• 6 32-bit status registers
Table 11-1 shows all the registers in all modes.
Table 11-1.
ARM9TDMI® Modes and Registers 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
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_ABORT
SPSR_UNDEF
SPSR_IRQ
SPSR_FIQ
Mode-specific banked registers
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The ARM state register set contains 16 directly-accessible registers, r0 to r15, and an additional register, the Current Program Status Register (CPSR). Registers r0 to r13 are generalpurpose registers used to hold either data or address values. Register r14 is used as a Link
register that holds a value (return address) of r15 when BL or BLX is executed. Register r15 is
used as a program counter (PC), whereas the Current Program Status Register (CPSR) contains condition code flags and the current mode bits.
In privileged modes (FIQ, Supervisor, Abort, IRQ, Undefined), mode-specific banked registers
(r8 to r14 in FIQ mode or r13 to r14 in the other modes) become available. The corresponding
banked registers r14_fiq, r14_svc, r14_abt, r14_irq, r14_und are similarly used to hold the values (return address for each mode) of r15 (PC) when interrupts and exceptions arise, or when
BL or BLX instructions are executed within interrupt or exception routines. There is another
register called Saved Program Status Register (SPSR) that becomes available in privileged
modes instead of CPSR. This register contains condition code flags and the current mode bits
saved as a result of the exception that caused entry to the current (privileged) mode.
In all modes and due to a software agreement, register r13 is used as stack pointer.
The use and the function of all the registers described above should obey ARM Procedure
Call Standard (APCS) which defines:
• constraints on the use of registers
• stack conventions
• argument passing and result return
The Thumb state register set is a subset of the ARM state set. The programmer has direct
access to:
• Eight general-purpose registers r0-r7
• Stack pointer, SP
• Link register, LR (ARM r14)
• PC
• CPSR
There are banked registers SPs, LRs and SPSRs for each privileged mode (for more details
see the ARM9EJ-S Technical Reference Manual, ref. DDI0222B, revision r1p2 page 2-12).
11.3.7.1
Status Registers
The ARM9EJ-S core contains one CPSR, and five SPSRs for exception handlers to use. The
program status registers:
• hold information about the most recently performed ALU operation
• control the enabling and disabling of interrupts
• set the processor operation mode
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Figure 11-2. Status Register Format
31 30 29 28 27
24
N Z C V Q
J
7 6 5
Reserved
I F T
Jazelle state bit
Reserved
Sticky Overflow
Overflow
Carry/Borrow/Extend
Zero
Negative/Less than
0
Mode
Mode bits
Thumb state bit
FIQ disable
IRQ disable
Figure 11-2 shows the status register format, where:
• N: Negative, Z: Zero, C: Carry, and V: Overflow are the four ALU flags
• The Sticky Overflow (Q) flag can be set by certain multiply and fractional arithmetic
instructions like QADD, QDADD, QSUB, QDSUB, SMLAxy, and SMLAWy needed to
achieve DSP operations.
The Q flag is sticky in that, when set by an instruction, it remains set until explicitly cleared
by an MSR instruction writing to the CPSR. Instructions cannot execute conditionally on the
status of the Q flag.
• The J bit in the CPSR indicates when the ARM9EJ-S core is in Jazelle state, where:
– J = 0: The processor is in ARM or Thumb state, depending on the T bit
– J = 1: The processor is in Jazelle state.
• Mode: five bits to encode the current processor mode
11.3.7.2
Exceptions
Exception Types and Priorities
The ARM9EJ-S supports five types of exceptions. Each type drives the ARM9EJ-S in a privileged mode. The types of exceptions are:
• Fast interrupt (FIQ)
• Normal interrupt (IRQ)
• Data and Prefetched aborts (Abort)
• Undefined instruction (Undefined)
• Software interrupt and Reset (Supervisor)
When an exception occurs, the banked version of R14 and the SPSR for the exception mode
are used to save the state.
More than one exception can happen at a time, therefore the ARM9EJ-S takes the arisen
exceptions according to the following priority order:
• Reset (highest priority)
• Data Abort
• FIQ
• IRQ
• Prefetch Abort
• BKPT, Undefined instruction, and Software Interrupt (SWI) (Lowest priority)
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The BKPT, or Undefined instruction, and SWI exceptions are mutually exclusive.
There is one exception in the priority scheme though, when FIQs are enabled and a Data
Abort occurs at the same time as an FIQ, the ARM9EJ-S core enters the Data Abort handler,
and proceeds immediately to FIQ vector. A normal return from the FIQ causes the Data Abort
handler to resume execution. Data Aborts must have higher priority than FIQs to ensure that
the transfer error does not escape detection.
Exception Modes and Handling
Exceptions arise whenever the normal flow of a program must be halted temporarily, for example, to service an interrupt from a peripheral.
When handling an ARM exception, the ARM9EJ-S core performs the following operations:
1. Preserves the address of the next instruction in the appropriate Link Register that
corresponds to the new mode that has been entered. When the exception entry is
from:
– ARM and Jazelle states, the ARM9EJ-S copies the address of the next instruction
into LR (current PC(r15) + 4 or PC + 8 depending on the exception).
– THUMB state, the ARM9EJ-S writes the value of the PC into LR, offset by a value
(current PC + 2, PC + 4 or PC + 8 depending on the exception) that causes the
program to resume from the correct place on return.
2. Copies the CPSR into the appropriate SPSR.
3. Forces the CPSR mode bits to a value that depends on the exception.
4. Forces the PC to fetch the next instruction from the relevant exception vector.
The register r13 is also banked across exception modes to provide each exception handler
with private stack pointer.
The ARM9EJ-S can also set the interrupt disable flags to prevent otherwise unmanageable
nesting of exceptions.
When an exception has completed, the exception handler must move both the return value in
the banked LR minus an offset to the PC and the SPSR to the CPSR. The offset value varies
according to the type of exception. This action restores both PC and the CPSR.
The fast interrupt mode has seven private registers r8 to r14 (banked registers) to reduce or
remove the requirement for register saving which minimizes the overhead of context
switching.
The Prefetch Abort is one of the aborts that indicates that the current memory access cannot
be completed. When a Prefetch Abort occurs, the ARM9EJ-S marks the prefetched instruction
as invalid, but does not take the exception until the instruction reaches the Execute stage in
the pipeline. If the instruction is not executed, for example because a branch occurs while it is
in the pipeline, the abort does not take place.
The breakpoint (BKPT) instruction is a new feature of ARM9EJ-S that is destined to solve the
problem of the Prefetch Abort. A breakpoint instruction operates as though the instruction
caused a Prefetch Abort.
A breakpoint instruction does not cause the ARM9EJ-S to take the Prefetch Abort exception
until the instruction reaches the Execute stage of the pipeline. If the instruction is not executed, for example because a branch occurs while it is in the pipeline, the breakpoint does not
take place.
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11.3.8
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]).
Table 11-2 gives the ARM instruction mnemonic list.
Table 11-2.
Mnemonic
Operation
Mnemonic
Operation
MOV
Move
MVN
Move Not
ADD
Add
ADC
Add with Carry
SUB
Subtract
SBC
Subtract with Carry
RSB
Reverse Subtract
RSC
Reverse Subtract with Carry
CMP
Compare
CMN
Compare Negated
TST
Test
TEQ
Test Equivalence
AND
Logical AND
BIC
Bit Clear
EOR
Logical Exclusive OR
ORR
Logical (inclusive) OR
MUL
Multiply
MLA
Multiply Accumulate
SMULL
Sign Long Multiply
UMULL
Unsigned Long Multiply
SMLAL
Signed Long Multiply
Accumulate
UMLAL
Unsigned Long Multiply
Accumulate
MSR
B
BX
LDR
Move to Status Register
Branch
MRS
BL
Move From Status Register
Branch and Link
Branch and Exchange
SWI
Software Interrupt
Load Word
STR
Store Word
LDRSH
Load Signed Halfword
LDRSB
Load Signed Byte
LDRH
Load Half Word
STRH
Store Half Word
LDRB
Load Byte
STRB
Store Byte
LDRBT
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ARM Instruction Mnemonic List
Load Register Byte with
Translation
STRBT
Store Register Byte with
Translation
LDRT
Load Register with
Translation
STRT
Store Register with
Translation
LDM
Load Multiple
STM
Store Multiple
SWP
Swap Word
SWPB
Swap Byte
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Table 11-2.
Mnemonic
11.3.9
Operation
Mnemonic
Operation
MCR
Move To Coprocessor
MRC
Move From Coprocessor
LDC
Load To Coprocessor
STC
Store From Coprocessor
CDP
Coprocessor Data
Processing
New ARM Instruction Set
.
Table 11-3.
Mnemonic
New ARM Instruction Mnemonic List
Operation
Mnemonic
Operation
Branch and exchange to
Java
MRRC
Move double from
coprocessor
BLX (1)
Branch, Link and exchange
MCR2
Alternative move of ARM reg
to coprocessor
SMLAxy
Signed Multiply Accumulate
16 * 16 bit
MCRR
Move double to coprocessor
SMLAL
Signed Multiply Accumulate
Long
CDP2
Alternative Coprocessor
Data Processing
SMLAWy
Signed Multiply Accumulate
32 * 16 bit
BKPT
Breakpoint
SMULxy
Signed Multiply 16 * 16 bit
PLD
SMULWy
Signed Multiply 32 * 16 bit
STRD
Store Double
Saturated Add
STC2
Alternative Store from
Coprocessor
Saturated Add with Double
LDRD
Load Double
Saturated subtract
LDC2
Alternative Load to
Coprocessor
BXJ
QADD
QDADD
QSUB
QDSUB
Notes:
11.3.10
ARM Instruction Mnemonic List (Continued)
Saturated Subtract with
double
CLZ
Soft Preload, Memory
prepare to load from address
Count Leading Zeroes
1. A Thumb BLX contains two consecutive Thumb instructions, and takes four cycles.
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
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Table 5 shows the Thumb instruction set. Table 11-4 gives the Thumb instruction mnemonic
list.
Table 11-4.
11.4
Thumb Instruction Mnemonic List
Mnemonic
Operation
Mnemonic
Operation
MOV
Move
MVN
Move Not
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
BLX
Branch, Link, and Exchange
B
Branch
BL
Branch and Link
BX
Branch and Exchange
SWI
Software Interrupt
LDR
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
BCC
Conditional Branch
BKPT
Breakpoint
CP15 Coprocessor
Coprocessor 15, or System Control Coprocessor CP15, is used to configure and control all the
items in the list below:
• ARM9EJ-S
• Caches (ICache, DCache and write buffer)
• TCM
• MMU
• Other system options
To control these features, CP15 provides 16 additional registers. See Table 11-5.
Table 11-5.
Register
0
54
CP15 Registers
Name
Read/Write
(1)
Read/Unpredictable
ID Code
0
Cache type
(1)
Read/Unpredictable
0
TCM status(1)
Read/Unpredictable
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Table 11-5.
CP15 Registers
Register
Name
Read/Write
1
Control
Read/write
2
Translation Table Base
Read/write
3
Domain Access Control
Read/write
4
Reserved
None
5
Data fault Status(1)
Notes:
Read/write
(1)
Read/write
5
Instruction fault status
6
Fault Address
Read/write
7
Cache Operations
Read/Write
8
TLB operations
Unpredictable/Write
(2)
9
cache lockdown
Read/write
9
TCM region
Read/write
10
TLB lockdown
Read/write
11
Reserved
None
12
Reserved
None
(1)
Read/write
13
FCSE PID
13
Context ID(1)
Read/Write
14
Reserved
None
15
Test configuration
Read/Write
1. Register locations 0,5, and 13 each provide access to more than one register. The register
accessed depends on the value of the opcode_2 field.
2. Register location 9 provides access to more than one register. The register accessed
depends on the value of the CRm field.
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11.4.1
CP15 Registers Access
CP15 registers can only be accessed in privileged mode by:
• MCR (Move to Coprocessor from ARM Register) instruction is used to write an ARM
register to CP15.
• MRC (Move to ARM Register from Coprocessor) instruction is used to read the value of
CP15 to an ARM register.
Other instructions like CDP, LDC, STC can cause an undefined instruction exception.
The assembler code for these instructions is:
MCR/MRC{cond} p15, opcode_1, Rd, CRn, CRm, opcode_2.
The MCR, MRC instructions bit pattern is shown below:
31
30
29
28
cond
23
22
21
opcode_1
15
20
13
12
Rd
6
26
25
24
1
1
1
0
19
18
17
16
L
14
7
27
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.
• L: Instruction Bit
0 = MCR instruction
1 = MRC instruction
• opcode_1[23:20]: Coprocessor Code
Defines the coprocessor specific code. Value is c15 for CP15.
• cond [31:28]: Condition
For more details, see Chapter 2 in ARM926EJ-S TRM, ref. DDI0198B.
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11.5
Memory Management Unit (MMU)
The ARM926EJ-S processor implements an enhanced ARM architecture v5 MMU to provide
virtual memory features required by operating systems like Symbian OS®, WindowsCE, and
Linux. These virtual memory features are memory access permission controls and virtual to
physical address translations.
The Virtual Address generated by the CPU core is converted to a Modified Virtual Address
(MVA) by the FCSE (Fast Context Switch Extension) using the value in CP15 register13. The
MMU translates modified virtual addresses to physical addresses by using a single, two-level
page table set stored in physical memory. Each entry in the set contains the access permissions and the physical address that correspond to the virtual address.
The first level translation tables contain 4096 entries indexed by bits [31:20] of the MVA.
These entries contain a pointer to either a 1 MB section of physical memory along with
attribute information (access permissions, domain, etc.) or an entry in the second level translation tables; coarse table and fine table.
The second level translation tables contain two subtables, coarse table and fine table. An
entry in the coarse table contains a pointer to both large pages and small pages along with
access permissions. An entry in the fine table contains a pointer to large, small and tiny pages.
Table 7 shows the different attributes of each page in the physical memory.
Table 11-6.
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
-
The MMU consists of:
• Access control logic
• Translation Look-aside Buffer (TLB)
• Translation table walk hardware
11.5.1
Access Control Logic
The access control logic controls access information for every entry in the translation table.
The access control logic checks two pieces of access information: domain and access permissions. The domain is the primary access control mechanism for a memory region; there are 16
of them. It defines the conditions necessary for an access to proceed. The domain determines
whether the access permissions are used to qualify the access or whether they should be
ignored.
The second access control mechanism is access permissions that are defined for sections
and for large, small and tiny pages. Sections and tiny pages have a single set of access permissions whereas large and small pages can be associated with 4 sets of access permissions,
one for each subpage (quarter of a page).
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11.5.2
Translation Look-aside Buffer (TLB)
The Translation Look-aside Buffer (TLB) caches translated entries and thus avoids going
through the translation process every time. When the TLB contains an entry for the MVA
(Modified Virtual Address), the access control logic determines if the access is permitted and
outputs the appropriate physical address corresponding to the MVA. If access is not permitted,
the MMU signals the CPU core to abort.
If the TLB does not contain an entry for the MVA, the translation table walk hardware is
invoked to retrieve the translation information from the translation table in physical memory.
11.5.3
Translation Table Walk Hardware
The translation table walk hardware is a logic that traverses the translation tables located in
physical memory, gets the physical address and access permissions and updates the TLB.
The number of stages in the hardware table walking is one or two depending whether the
address is marked as a section-mapped access or a page-mapped access.
There are three sizes of page-mapped accesses and one size of section-mapped access.
Page-mapped accesses are for large pages, small pages and tiny pages. The translation process always begins with a level one fetch. A section-mapped access requires only a level one
fetch, but a page-mapped access requires an additional level two fetch. For further details on
the MMU, please refer to chapter 3 in ARM926EJ-S Technical Reference Manual, ref.
DDI0198B.
11.5.4
MMU Faults
The MMU generates an abort on the following types of faults:
• Alignment faults (for data accesses only)
• Translation faults
• Domain faults
• Permission faults
The access control mechanism of the MMU detects 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 retains status and address information about faults generated by the data
accesses in the data fault status register and fault address register. It also retains the status of
faults generated by instruction fetches in the instruction fault status register.
The fault status register (register 5 in CP15) indicates the cause of a data or prefetch abort,
and the domain number of the aborted access when it happens. The fault address register
(register 6 in CP15) holds the MVA associated with the access that caused the Data Abort. For
further details on MMU faults, please refer to chapter 3 in ARM926EJ-S Technical Reference
Manual, ref. DDI0198B.
11.6
Caches and Write Buffer
The ARM926EJ-S contains a 16 KB Instruction Cache (ICache), a 16 KB Data Cache
(DCache), and a write buffer. Although the ICache and DCache share common features, each
still has some specific mechanisms.
The caches (ICache and DCache) are four-way set associative, addressed, indexed and
tagged using the Modified Virtual Address (MVA), with a cache line length of eight words with
two dirty bits for the DCache. The ICache and DCache provide mechanisms for cache lockdown, cache pollution control, and line replacement.
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A new feature is now supported by ARM926EJ-S caches called allocate on read-miss commonly known as wrapping. This feature enables the caches to perform critical word first cache
refilling. This means that when a request for a word causes a read-miss, the cache performs
an AHB access. Instead of loading the whole line (eight words), the cache loads the critical
word first, so the processor can reach it quickly, and then the remaining words, no matter
where the word is located in the line.
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 ICache caches fetched instructions to be executed by the processor. The ICache can be
enabled by writing 1 to I bit of the CP15 Register 1 and disabled by writing 0 to this same bit.
When the MMU is enabled, all instruction fetches are subject to translation and permission
checks. If the MMU is disabled, all instructions fetches are cachable, no protection checks are
made and the physical address is flat-mapped to the modified virtual address. With the MVA
use disabled, context switching incurs ICache cleaning and/or invalidating.
When the ICache is disabled, all instruction fetches appear on external memory (AHB) (see
Tables 4-1 and 4-2 in page 4-4 in ARM926EJ-S TRM, ref. DDI0198B).
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.
11.6.2
11.6.2.1
Data Cache (DCache) and Write Buffer
ARM926EJ-S includes a DCache and a write buffer to reduce the effect of main memory
bandwidth and latency on data access performance. The operations of DCache and write
buffer are closely connected.
DCache
The DCache needs the MMU to be enabled. All data accesses are subject to MMU permission
and translation checks. Data accesses that are aborted by the MMU do not cause linefills or
data accesses to appear on the AMBA ASB interface. If the MMU is disabled, all data
accesses are noncachable, nonbufferable, with no protection checks, and appear on the AHB
bus. All addresses are flat-mapped, VA = MVA = PA, which incurs DCache cleaning and/or
invalidating every time a context switch occurs.
The DCache stores the Physical Address Tag (PA Tag) from which every line was loaded and
uses it when writing modified lines back to external memory. This means that the MMU is not
involved in write-back operations.
Each line (8 words) in the DCache has two dirty bits, one for the first four words and the other
one for the second four words. These bits, if set, mark the associated half-lines as dirty. If the
cache line is replaced due to a linefill or a cache clean operation, the dirty bits are used to
decide whether all, half or none is written back to memory.
DCache can be enabled or disabled by writing either 1 or 0 to bit C in register 1 of CP15 (see
Tables 4-3 and 4-4 on page 4-5 in ARM926EJ-S TRM, ref. DDI0222B).
The DCache supports write-through and write-back cache operations, selected by memory
region using the C and B bits in the MMU translation tables.
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The DCache contains an eight data word entry, single address entry write-back buffer used to
hold write-back data for cache line eviction or cleaning of dirty cache lines.
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.
11.6.2.2
Write Buffer
The ARM926EJ-S contains a write buffer that has a 16-word data buffer and a four- address
buffer. The write buffer is used for all writes to a bufferable region, write-through region and
write-back region. It also allows to avoid stalling the processor when writes to external memory
are performed. When a store occurs, data is written to the write buffer at core speed (high
speed). The write buffer then completes the store to external memory at bus speed (typically
slower than the core speed). During this time, the ARM9EJ-S processor can preform other
tasks.
DCache and Write Buffer support write-back and write-through memory regions, controlled by
C and B bits in each section and page descriptor within the MMU translation tables.
Write-though Operation
When a cache write hit occurs, the DCache line is updated. The updated data is then written to
the write buffer which transfers it to external memory.
When a cache write miss occurs, a line, chosen by round robin or another algorithm, is stored
in the write buffer which transfers it to external memory.
Write-back Operation
When a cache write hit occurs, the cache line or half line is marked as dirty, meaning that its
contents are not up-to-date with those in the external memory.
When a cache write miss occurs, a line, chosen by round robin or another algorithm, is stored
in the write buffer which transfers it to external memory.
11.7
11.7.1
Tightly-Coupled Memory Interface
TCM Description
The ARM926EJ-S processor features a Tightly-Coupled Memory (TCM) interface, which
enables separate instruction and data TCMs (ITCM and DTCM) to be directly reached by the
processor. TCMs are used to store real-time and performance critical code, they also provide
a DMA support mechanism. Unlike AHB accesses to external memories, accesses to TCMs
are fast and deterministic and do not incur bus penalties.
The user has the possibility to independently configure each TCM size with values within the
following ranges, [0KB, 64 KB] for ITCM size and [0KB, 64 KB] for DTCM size.
TCMs can be configured by two means: HMATRIX TCM register and TCM region register
(register 9) in CP15 and both steps should be performed. HMATRIX TCM register sets TCM
size whereas TCM region register (register 9) in CP15 maps TCMs and enables them.
The data side of the ARM9EJ-S core is able to access the ITCM. This is necessary to enable
code to be loaded into the ITCM, for SWI and emulated instruction handlers, and for accesses
to PC-relative literal pools.
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11.7.2
Enabling and Disabling TCMs
Prior to any enabling step, the user should configure the TCM sizes in HMATRIX TCM register. Then enabling TCMs is performed by using TCM region register (register 9) in CP15. The
user should use the same sizes as those put in HMATRIX TCM register. For further details
and programming tips, please refer to chapter 2.3 in ARM926EJ-S TRM, ref. DDI0222B.
11.7.3
TCM Mapping
The TCMs can be located anywhere in the memory map, with a single region available for
ITCM and a separate region available for DTCM. The TCMs are physically addressed and can
be placed anywhere in physical address space. However, the base address of a TCM must be
aligned to its size, and the DTCM and ITCM regions must not overlap. TCM mapping is performed by using TCM region register (register 9) in CP15. The user should input the right
mapping address for TCMs.
11.8
Bus Interface Unit
The ARM926EJ-S features a Bus Interface Unit (BIU) that arbitrates and schedules AHB
requests. The BIU implements a multi-layer AHB, based on the AHB-Lite protocol, that
enables parallel access paths between multiple AHB masters and slaves in a system. This is
achieved by using a more complex interconnection matrix and gives the benefit of increased
overall bus bandwidth, and a more flexible system architecture.
The multi-master bus architecture has a number of benefits:
• It allows the development of multi-master systems with an increased bus bandwidth and a
flexible architecture.
• Each AHB layer becomes simple because it only has one master, so no arbitration or
master-to-slave muxing is required. AHB layers, implementing AHB-Lite protocol, do not
have to support request and grant, nor do they have to support retry and split transactions.
• The arbitration becomes effective when more than one master wants to access the same
slave simultaneously.
11.8.1
Supported Transfers
The ARM926EJ-S processor performs all AHB accesses as single word, bursts of four words,
or bursts of eight words. Any ARM9EJ-S core request that is not 1, 4, 8 words in size is split
into packets of these sizes. Note that the Atmel bus is AHB-Lite protocol compliant, hence it
does not support split and retry requests.
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Table 8 gives an overview of the supported transfers and different kinds of transactions they
are used for.
Table 11-7.
HBurst[2:0]
Supported Transfers
Description
Single transfer of word, half word, or byte:
• data write (NCNB, NCB, WT, or WB that has missed in DCache)
SINGLE
Single transfer
• data read (NCNB or NCB)
• NC instruction fetch (prefetched and non-prefetched)
• page table walk read
INCR4
Four-word incrementing burst
Half-line cache write-back, Instruction prefetch, if enabled. Four-word burst NCNB,
NCB, WT, or WB write.
INCR8
Eight-word incrementing burst
Full-line cache write-back, eight-word burst NCNB, NCB, WT, or WB write.
WRAP8
Eight-word wrapping burst
Cache linefill
11.8.2
Thumb Instruction Fetches
All instructions fetches, regardless of the state of ARM9EJ-S core, are made as 32-bit
accesses on the AHB. If the ARM9EJ-S is in Thumb state, then two instructions can be
fetched at a time.
11.8.3
Address Alignment
The ARM926EJ-S BIU performs address alignment checking and aligns AHB addresses to the
necessary boundary. 16-bit accesses are aligned to halfword boundaries, and 32-bit accesses
are aligned to word boundaries.
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12. AT91SAM9263 Debug and Test
12.1
Description
The AT91SAM9263 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, halfrate 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 gives direct access to these capabilities
from a PC-based test environment.
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12.2
Block Diagram
Figure 12-1. Debug and Test Block Diagram
TMS
TCK
TDI
NTRST
ICE/JTAG
TAP
Boundary
Port
JTAGSEL
TDO
RTCK
POR
Reset
and
Test
TST
ARM9EJ-S
ICE-RT
PIO
TPK0-TPK15
ETM
TPS0-TPS2
TSYNC
2
TCLK
ARM926EJ-S
DTXD
PDC
DBGU
DRXD
TAP: Test Access Port
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12.3
12.3.1
Application Examples
Debug Environment
Figure 12-2 on page 65 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. Application Debug and Trace Environment Example
Host Debugger
ICE/JTAG
Interface
Trace Port
Interface
ICE/JTAG
Connector
Trace
Connector
RS232
Connector
NADIA2
Terminal
AT91SAM9263-based Application
12.3.2
Test Environment
Figure 12-3 on page 65 shows a test environment example. Test vectors are sent and interpreted by the tester. In this example, the “board in test” is designed using a number of JTAGcompliant devices. These devices can be connected to form a single scan chain.
Figure 12-3. Application Test Environment Example
Test Adaptor
Tester
JTAG
Interface
ICE/JTAG
Connector
NADIA2
Chip n
Chip 2
Chip 1
AT91SAM9263-based Application Board In Test
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12.4
Debug and Test Pin Description
Table 12-1.
Pin Name
Debug and Test Pin List
Function
Type
Active Level
Input
Low
Input/Output
Low
Input
High
Reset/Test
NTRST
Test Reset Signal
NRST
Microcontroller Reset
TST
Test Mode Select
ICE and JTAG
TCK
Test Clock
Input
TDI
Test Data In
Input
TDO
Test Data Out
TMS
Test Mode Select
RTCK
Returned Test Clock
JTAGSEL
JTAG Selection
Output
Input
Output
Input
ETM
TSYNC
Trace Synchronization Signal
Output
TCLK
Trace Clock
Output
TPS0 - TPS2
Trace ARM Pipeline Status
Output
TPK0 - TPK15
Trace Packet Port
Output
Debug Unit
12.5
12.5.1
DRXD
Debug Receive Data
Input
DTXD
Debug Transmit Data
Output
Functional Description
Test Pin
One dedicated pin, TST, is used to define the device operating mode. The user must make
sure that this pin is tied at low level to ensure normal operating conditions. Other values associated with this pin are reserved for manufacturing test.
12.5.2
Embedded In-circuit Emulator
The ARM9EJ-S Embedded In-Circuit Emulator-RT is supported via the ICE/JTAG port. It is
connected to a host computer via an ICE interface. Debug support is implemented using an
ARM9EJ-S core embedded within the ARM926EJ-S. The internal state of the ARM926EJ-S 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 ARM9EJ-S registers. This data can be serially shifted out without affecting the rest of the
system.
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There are two scan chains inside the ARM9EJ-S processor which support testing, debugging,
and programming of the Embedded ICE-RT. 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 after JTAGSEL is
changed.
For further details on the Embedded In-Circuit-Emulator-RT, see the ARM document:
ARM9EJ-S Technical Reference Manual (DDI 0222A).
12.5.3
JTAG Signal Description
TMS is the Test Mode Select input which controls the transitions of the test interface state
machine.
TDI is the Test Data Input line which supplies the data to the JTAG registers (Boundary Scan
Register, Instruction Register, or other data registers).
TDO is the Test Data Output line which is used to serially output the data from the JTAG registers to the equipment controlling the test. It carries the sampled values from the boundary
scan chain (or other JTAG registers) and propagates them to the next chip in the serial test
circuit.
NTRST (optional in IEEE Standard 1149.1) is a Test-ReSeT input which is mandatory in ARM
cores and used to reset the debug logic. On Atmel ARM926EJ-S-based cores, NTRST is a
Power On Reset output. It is asserted on power on. If necessary, the user can also reset the
debug logic with the NTRST pin assertion during 2.5 MCK periods.
TCK is the Test ClocK input which enables the test interface. TCK is pulsed by the equipment
controlling the test and not by the tested device. It can be pulsed at any frequency. Note the
maximum JTAG clock rate on ARM926EJ-S cores is 1/6th the clock of the CPU. This gives
5.45 kHz maximum initial JTAG clock rate for an ARM9E running from the 32.768 kHz slow
clock.
RTCK is the Return Test Clock. Not an IEEE Standard 1149.1 signal added for a better clock
handling by emulators. From some ICE Interface probes, this return signal can be used to synchronize the TCK clock and take not care about the given ratio between the ICE Interface
clock and system clock equal to 1/6th. This signal is only available in JTAG ICE Mode and not
in boundary scan mode.
12.5.4
Debug Unit
The Debug Unit provides a two-pin (DXRD and TXRD) USART 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 association with two peripheral data controller
channels permits 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 that trace the activity of the Debug Communication Channel.The
Debug Unit allows blockage of access to the system through the ICE interface.
A specific register, the Debug Unit Chip ID Register, gives information about the product version and its internal configuration.
The AT91SAM9263 Debug Unit Chip ID value is 0x0196 07A0 on 32-bit width.
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For further details on the Debug Unit, see the Debug Unit section.
12.5.5
Embedded Trace Macrocell
The AT91SAM9263 features an Embedded Trace Macrocell (ETM), which is closely connected to the ARM926EJ-S Processor. The Embedded Trace is a standard Medium+ level
implementation and contains the following resources:
• Four pairs of address comparators
• Two data comparators
• Eight memory map decoder inputs
• Two 16-bits counters
• One 3-stage sequencer
• Four external inputs
• One external output
• One 45-byte FIFO
The Embedded Trace Macrocell of the AT91SAM9263 works in half-rate clock mode and thus
integrates a clock divider. This allows the maximum frequency of all the trace port signals not
to exceed one half of the ARM926EJ-S clock speed.
The Embedded Trace Macrocell input and output resources are not used in the
AT91SAM9263.
The Embedded Trace is a real-time trace module with the capability of tracing the ARM9EJ-S
instruction and data.
For further details on Embedded Trace Macrocell, see the ARM documents:
• ETM9 (Rev2p2) Technical Reference Manual (DDI 0157F)
• Embedded Trace Macrocell Specification (IHI 0014J)
12.5.5.1
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 ARM926EJ-S 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.
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Figure 12-4. ETM9 Block
TPS-TPS0
ARM926EJ-S
Bus Tracker
Trace
Control
FIFO
TPK15-TPK0
TSYNC
Trace Enable, View Data
TAP
Controller
Trigger, Sequencer, Counters
Scan Chain 6
12.5.5.2
TDO
TDI
TMS
TCK
ETM9
Implementation Details
This section gives an overview of the Embedded Trace resources.
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 configurated 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.
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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
Product Resource
Area
Access Type
Start Address
End Address
SRAM
Internal
Data
0x0000 0000
0x002F FFFF
SRAM
Internal
Fetch
0x0000 0000
0x002F FFFF
ROM
Internal
Data
0x0040 0000
0x004F FFFF
ROM
Internal
Fetch
0x0040 0000
0x004F FFFF
External Bus Interface
External
Data
0x1000 0000
0x9FFF FFFF
External Bus Interface
External
Fetch
0x1000 0000
0x9FFF FFFF
User Peripherals
Internal
Data
0xF000 0000
0xFFFF BFFF
System Peripherals
Internal
Data
0xFFFF C000
0xFFFF FFFF
FIFO
A 45-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.
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.
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12.5.5.3
Application Board Restriction
The TCLK signal needs to be set with care, some timing parameters are required. See “ETM
Timings” for more details.
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
NADIA2-based
Application Board
38 37
2
1
Pin 1Chamfer
12.5.6
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 after JTAGSEL is changed.
A Boundary-scan Descriptor Language (BSDL) file is provided to set up test.
12.5.6.1
JTAG Boundary-scan Register
The Boundary-scan Register (BSR) contains 664 bits that correspond to active pins and associated control signals.
Each AT91SAM9263 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 CONTROL bit selects the direction of the pad.
Table 12-3.
Bit
Number
AT91SAM9263 JTAG Boundary Scan Register
Pin Name
Pin Type
663
662
661
Associated
BSR Cells
INPUT
PA19
IN/OUT
OUTPUT
CONTROL
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Table 12-3.
AT91SAM9263 JTAG Boundary Scan Register (Continued)
Bit
Number
Pin Name
Pin Type
660
659
INPUT
PA20
IN/OUT
OUTPUT
658
CONTROL
657
INPUT
656
PA21
IN/OUT
OUTPUT
655
CONTROL
654
INPUT
653
PA22
IN/OUT
OUTPUT
652
CONTROL
651
INPUT
650
PA23
IN/OUT
OUTPUT
649
CONTROL
648
INPUT
647
PA24
IN/OUT
OUTPUT
646
CONTROL
645
INPUT
644
PA25
IN/OUT
OUTPUT
643
CONTROL
642
INPUT
641
PA26
IN/OUT
OUTPUT
640
CONTROL
639
INPUT
638
PA27
IN/OUT
OUTPUT
637
CONTROL
636
INPUT
635
PA28
IN/OUT
OUTPUT
634
CONTROL
633
INPUT
632
PA29
IN/OUT
OUTPUT
631
CONTROL
630
INPUT
629
628
72
Associated
BSR Cells
PA30
IN/OUT
OUTPUT
CONTROL
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Table 12-3.
Bit
Number
AT91SAM9263 JTAG Boundary Scan Register (Continued)
Pin Name
Pin Type
627
626
Associated
BSR Cells
INPUT
PA31
IN/OUT
625
OUTPUT
CONTROL
624
EBI1_A0_NBS0
623
EBI1_A[7:0]
OUT
OUTPUT
CONTROL
622
INPUT
EBI1_A1_NWR2
IN/OUT
621
OUTPUT
620
EBI1_A2
OUT
OUTPUT
619
EBI1_A3
OUT
OUTPUT
618
EBI1_A4
OUT
OUTPUT
617
EBI1_A5
OUT
OUTPUT
616
EBI1_A6
OUT
OUTPUT
615
EBI1_A7
OUT
OUTPUT
614
EBI1_A8
OUT
OUTPUT
613
EBI1_A[15:8]
612
EBI1_A9
OUT
OUTPUT
611
EBI1_A10
OUT
OUTPUT
610
EBI1_A11
OUT
OUTPUT
609
EBI1_A12
OUT
OUTPUT
608
EBI1_A13
OUT
OUTPUT
607
EBI1_A14
OUT
OUTPUT
606
EBI1_A15
OUT
OUTPUT
605
EBI1_A16_BA0
OUT
OUTPUT
604
EBI1_A[22:16]
603
EBI1_A17
OUT
OUTPUT
602
EBI1_A18
OUT
OUTPUT
601
EBI1_A19
OUT
OUTPUT
600
EBI1_A20
OUT
OUTPUT
599
EBI1_A21
OUT
OUTPUT
598
EBI1_A22
OUT
OUTPUT
597
EBI1_NCS0
OUT
OUTPUT
596
EBI1_NCS0/EBI1_NRD/EBI1_NWR_NWR0/
EBI1_NWR_NWR1
595
EBI1_NRD
OUT
EBI1_NWR_NWR0
IN/OUT
CONTROL
CONTROL
CONTROL
594
593
OUTPUT
INPUT
OUTPUT
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Table 12-3.
AT91SAM9263 JTAG Boundary Scan Register (Continued)
Bit
Number
Pin Name
Pin Type
EBI1_NWR_NWR1
IN/OUT
592
INPUT
591
OUTPUT
590
INPUT
589
EBI1_D0
IN/OUT
OUTPUT
588
CONTROL
587
INPUT
586
EBI1_D1
IN/OUT
OUTPUT
585
CONTROL
584
INPUT
583
EBI1_D2
IN/OUT
OUTPUT
582
CONTROL
581
INPUT
580
EBI1_D3
IN/OUT
OUTPUT
579
CONTROL
578
INPUT
577
EBI1_D4
IN/OUT
OUTPUT
576
CONTROL
575
INPUT
574
EBI1_D5
IN/OUT
OUTPUT
573
CONTROL
572
INPUT
571
EBI1_D6
IN/OUT
OUTPUT
570
CONTROL
569
INPUT
568
EBI1_D7
IN/OUT
OUTPUT
567
CONTROL
566
INPUT
565
EBI1_D8
IN/OUT
OUTPUT
564
CONTROL
563
INPUT
562
EBI1_D9
IN/OUT
OUTPUT
561
CONTROL
560
INPUT
559
558
74
Associated
BSR Cells
EBI1_D10
IN/OUT
OUTPUT
CONTROL
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Table 12-3.
Bit
Number
AT91SAM9263 JTAG Boundary Scan Register (Continued)
Pin Name
Pin Type
557
556
Associated
BSR Cells
INPUT
EBI1_D11
IN/OUT
OUTPUT
555
CONTROL
554
INPUT
553
EBI1_D12
IN/OUT
OUTPUT
552
CONTROL
551
INPUT
550
EBI1_D13
IN/OUT
OUTPUT
549
CONTROL
548
INPUT
547
EBI1_D14
IN/OUT
OUTPUT
546
CONTROL
545
INPUT
544
EBI1_D15
IN/OUT
OUTPUT
543
CONTROL
542
INPUT
541
PE20
IN/OUT
OUTPUT
540
CONTROL
539
INPUT
538
PE21
IN/OUT
OUTPUT
537
CONTROL
536
INPUT
535
PE22
IN/OUT
OUTPUT
534
CONTROL
533
INPUT
532
PE23
IN/OUT
OUTPUT
531
CONTROL
530
INPUT
529
PE24
IN/OUT
OUTPUT
528
CONTROL
527
INPUT
526
525
PE26
IN/OUT
OUTPUT
CONTROL
75
6249B–ATARM–14-Dec-06
Table 12-3.
AT91SAM9263 JTAG Boundary Scan Register (Continued)
Bit
Number
Pin Name
Pin Type
524
523
INPUT
PE25
IN/OUT
OUTPUT
522
CONTROL
521
INPUT
520
PE27
IN/OUT
519
518
internal
517
internal
516
internal
514
OUTPUT
CONTROL
515
INPUT
PE28
IN/OUT
OUTPUT
513
CONTROL
512
INPUT
511
PE29
IN/OUT
OUTPUT
510
CONTROL
509
INPUT
508
PE30
IN/OUT
OUTPUT
507
CONTROL
506
INPUT
505
PE31
IN/OUT
504
OUTPUT
CONTROL
503
OUTPUT
RTCK
OUT
502
CONTROL
501
INPUT
500
PA0
IN/OUT
OUTPUT
499
CONTROL
498
INPUT
497
PA1
IN/OUT
OUTPUT
496
CONTROL
495
INPUT
494
PA2
IN/OUT
OUTPUT
493
CONTROL
492
INPUT
491
490
76
Associated
BSR Cells
PA3
IN/OUT
OUTPUT
CONTROL
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Table 12-3.
Bit
Number
AT91SAM9263 JTAG Boundary Scan Register (Continued)
Pin Name
Pin Type
489
488
Associated
BSR Cells
INPUT
PA4
IN/OUT
OUTPUT
487
CONTROL
486
INPUT
485
PA5
IN/OUT
OUTPUT
484
CONTROL
483
INPUT
482
PA6
IN/OUT
OUTPUT
481
CONTROL
480
INPUT
479
PA7
IN/OUT
OUTPUT
478
CONTROL
477
INPUT
476
PA8
IN/OUT
OUTPUT
475
CONTROL
474
INPUT
473
PA9
IN/OUT
OUTPUT
472
CONTROL
471
INPUT
470
PA10
IN/OUT
OUTPUT
469
CONTROL
468
INPUT
467
PA11
IN/OUT
OUTPUT
466
CONTROL
465
INPUT
464
PA12
IN/OUT
OUTPUT
463
CONTROL
462
INPUT
461
PA13
IN/OUT
OUTPUT
460
CONTROL
459
INPUT
458
457
PA14
IN/OUT
OUTPUT
CONTROL
77
6249B–ATARM–14-Dec-06
Table 12-3.
AT91SAM9263 JTAG Boundary Scan Register (Continued)
Bit
Number
Pin Name
Pin Type
456
455
INPUT
PA15
IN/OUT
OUTPUT
454
CONTROL
453
INPUT
452
PB0
IN/OUT
OUTPUT
451
CONTROL
450
INPUT
449
PB1
IN/OUT
OUTPUT
448
CONTROL
447
INPUT
446
PB2
IN/OUT
OUTPUT
445
CONTROL
444
INPUT
443
PB3
IN/OUT
OUTPUT
442
CONTROL
441
INPUT
440
PB4
IN/OUT
OUTPUT
439
CONTROL
438
INPUT
437
PB5
IN/OUT
OUTPUT
436
CONTROL
435
INPUT
434
PB6
IN/OUT
OUTPUT
433
CONTROL
432
INPUT
431
PB7
IN/OUT
OUTPUT
430
CONTROL
429
INPUT
428
PB8
IN/OUT
OUTPUT
427
CONTROL
426
INPUT
425
424
78
Associated
BSR Cells
PB9
IN/OUT
OUTPUT
CONTROL
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Table 12-3.
Bit
Number
AT91SAM9263 JTAG Boundary Scan Register (Continued)
Pin Name
Pin Type
423
422
Associated
BSR Cells
INPUT
PB10
IN/OUT
OUTPUT
421
CONTROL
420
INPUT
419
PB11
IN/OUT
OUTPUT
418
CONTROL
417
INPUT
416
PB12
IN/OUT
OUTPUT
415
CONTROL
414
INPUT
413
PB13
IN/OUT
OUTPUT
412
CONTROL
411
INPUT
410
PB14
IN/OUT
OUTPUT
409
CONTROL
408
INPUT
407
PB15
IN/OUT
OUTPUT
406
CONTROL
405
INPUT
404
PB16
IN/OUT
OUTPUT
403
CONTROL
402
INPUT
401
PB17
IN/OUT
OUTPUT
400
CONTROL
399
INPUT
398
PB18
IN/OUT
OUTPUT
397
CONTROL
396
INPUT
395
PB19
IN/OUT
OUTPUT
394
CONTROL
393
INPUT
392
391
PB20
IN/OUT
OUTPUT
CONTROL
79
6249B–ATARM–14-Dec-06
Table 12-3.
AT91SAM9263 JTAG Boundary Scan Register (Continued)
Bit
Number
Pin Name
Pin Type
390
389
INPUT
PB21
IN/OUT
OUTPUT
388
CONTROL
387
INPUT
386
PB22
IN/OUT
OUTPUT
385
CONTROL
384
INPUT
383
PB23
IN/OUT
OUTPUT
382
CONTROL
381
INPUT
380
PB24
IN/OUT
OUTPUT
379
CONTROL
378
INPUT
377
PB25
IN/OUT
OUTPUT
376
CONTROL
375
INPUT
374
PB26
IN/OUT
OUTPUT
373
CONTROL
372
INPUT
371
PB27
IN/OUT
OUTPUT
370
CONTROL
369
INPUT
368
PB28
IN/OUT
OUTPUT
367
CONTROL
366
INPUT
365
PB29
IN/OUT
OUTPUT
364
CONTROL
363
INPUT
362
PB30
IN/OUT
OUTPUT
361
CONTROL
360
INPUT
359
358
80
Associated
BSR Cells
PB31
IN/OUT
OUTPUT
CONTROL
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Table 12-3.
Bit
Number
AT91SAM9263 JTAG Boundary Scan Register (Continued)
Pin Name
Pin Type
357
356
Associated
BSR Cells
INPUT
PC0
IN/OUT
OUTPUT
355
CONTROL
354
INPUT
353
PC1
IN/OUT
OUTPUT
352
CONTROL
351
INPUT
350
PC2
IN/OUT
OUTPUT
349
CONTROL
348
INPUT
347
PC3
IN/OUT
OUTPUT
346
CONTROL
345
INPUT
344
PC4
IN/OUT
OUTPUT
343
CONTROL
342
INPUT
341
PC5
IN/OUT
OUTPUT
340
CONTROL
339
INPUT
338
PC6
IN/OUT
OUTPUT
337
CONTROL
336
INPUT
335
PC7
IN/OUT
OUTPUT
334
CONTROL
333
INPUT
332
PC8
IN/OUT
OUTPUT
331
CONTROL
330
INPUT
329
PC9
IN/OUT
OUTPUT
328
CONTROL
327
INPUT
326
325
PC10
IN/OUT
OUTPUT
CONTROL
81
6249B–ATARM–14-Dec-06
Table 12-3.
AT91SAM9263 JTAG Boundary Scan Register (Continued)
Bit
Number
Pin Name
Pin Type
324
323
INPUT
PC11
IN/OUT
OUTPUT
322
CONTROL
321
INPUT
320
PC12
IN/OUT
OUTPUT
319
CONTROL
318
INPUT
317
PC13
IN/OUT
OUTPUT
316
CONTROL
315
INPUT
314
PC14
IN/OUT
OUTPUT
313
CONTROL
312
INPUT
311
PC15
IN/OUT
OUTPUT
310
CONTROL
309
INPUT
308
PC16
IN/OUT
OUTPUT
307
CONTROL
306
INPUT
305
PC17
IN/OUT
OUTPUT
304
CONTROL
303
INPUT
302
PC18
IN/OUT
OUTPUT
301
CONTROL
300
INPUT
299
PC19
IN/OUT
OUTPUT
298
CONTROL
297
INPUT
296
PC20
IN/OUT
OUTPUT
295
CONTROL
294
INPUT
293
292
82
Associated
BSR Cells
PC21
IN/OUT
OUTPUT
CONTROL
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Table 12-3.
Bit
Number
AT91SAM9263 JTAG Boundary Scan Register (Continued)
Pin Name
Pin Type
291
290
Associated
BSR Cells
INPUT
PC22
IN/OUT
OUTPUT
289
CONTROL
288
INPUT
287
PC23
IN/OUT
OUTPUT
286
CONTROL
285
INPUT
284
PC24
IN/OUT
OUTPUT
283
CONTROL
282
INPUT
281
PC25
IN/OUT
OUTPUT
280
CONTROL
279
INPUT
278
PC26
IN/OUT
OUTPUT
277
CONTROL
276
INPUT
275
PC27
IN/OUT
OUTPUT
274
CONTROL
273
INPUT
272
PC28
IN/OUT
OUTPUT
271
CONTROL
270
INPUT
269
PC29
IN/OUT
OUTPUT
268
CONTROL
267
INPUT
266
PC30
IN/OUT
OUTPUT
265
CONTROL
264
INPUT
263
PC31
IN/OUT
OUTPUT
262
CONTROL
261
INPUT
260
259
PD0
IN/OUT
OUTPUT
CONTROL
83
6249B–ATARM–14-Dec-06
Table 12-3.
AT91SAM9263 JTAG Boundary Scan Register (Continued)
Bit
Number
Pin Name
Pin Type
258
INPUT
257
PD1
IN/OUT
OUTPUT
256
CONTROL
255
INPUT
254
PD2
IN/OUT
OUTPUT
253
CONTROL
252
INPUT
251
PD3
IN/OUT
OUTPUT
250
CONTROL
249
INPUT
248
PD4
IN/OUT
247
OUTPUT
CONTROL
246
PPS
OUT
OUTPUT
245
EBI0_A0_NBS0
OUT
OUTPUT
244
EBI0_A[7:0]
CONTROL
243
INPUT
EBI0_A1_NBS2_NWR2
IN/OUT
242
84
Associated
BSR Cells
OUTPUT
241
EBI0_A2
OUT
OUTPUT
240
EBI0_A3
OUT
OUTPUT
239
EBI0_A4
OUT
OUTPUT
238
EBI0_A5
OUT
OUTPUT
237
EBI0_A6
OUT
OUTPUT
236
EBI0_A7
OUT
OUTPUT
235
EBI0_A8
OUT
OUTPUT
234
EBI0_A[15:8]
233
EBI0_A9
OUT
OUTPUT
232
EBI0_A10
OUT
OUTPUT
231
EBI0_SDA10
OUT
OUTPUT
230
EBI0_SDA10/SDCKE/RAS/CAS/
SDWE/NANDOE/NANDWE
229
EBI0_A11
OUT
OUTPUT
228
EBI0_A12
OUT
OUTPUT
227
EBI0_A13
OUT
OUTPUT
226
EBI0_A14
OUT
OUTPUT
225
EBI0_A15
OUT
OUTPUT
224
EBI0_A16_BA0
OUT
OUTPUT
CONTROL
CONTROL
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Table 12-3.
AT91SAM9263 JTAG Boundary Scan Register (Continued)
Bit
Number
Pin Name
223
EBI0_A[22:16]
222
EBI0_A17_BA1
OUT
OUTPUT
221
EBI0_A18
OUT
OUTPUT
220
EBI0_A19
OUT
OUTPUT
219
EBI0_A20
OUT
OUTPUT
218
EBI0_A21
OUT
OUTPUT
217
EBI0_A22
OUT
OUTPUT
216
EBI0_NCS0
OUT
OUTPUT
215
EBI0_NCS0/EBI0_NCS1_SDCS/EBI0_NRD/
EBI0_NWR_NWR0/EBI0_NBS1_NWR1/EBI0_NBS3_NWR3
214
EBI0_NCS1_SDCS
OUT
OUTPUT
213
EBI0_NRD
OUT
OUTPUT
EBI0_NWR_NWR0
IN/OUT
Pin Type
Associated
BSR Cells
CONTROL
CONTROL
212
INPUT
211
OUTPUT
210
INPUT
EBI0_NBS1_NWR1
IN/OUT
209
OUTPUT
208
INPUT
EBI0_NBS3_NWR3
IN/OUT
207
OUTPUT
206
internal
205
internal
204
internal
203
EBI0_SDCK
OUT
OUTPUT
202
EBI0_RAS
OUT
OUTPUT
201
EBI0_CAS
OUT
OUTPUT
200
EBI0_SDWE
OUT
OUTPUT
199
EBI0_NANDOE
OUT
OUTPUT
198
EBI0_NANDWE
OUT
OUTPUT
197
196
INPUT
EBI0_D0
IN/OUT
OUTPUT
195
CONTROL
194
INPUT
193
EBI0_D1
IN/OUT
OUTPUT
192
CONTROL
191
INPUT
190
189
EBI0_D2
IN/OUT
OUTPUT
CONTROL
85
6249B–ATARM–14-Dec-06
Table 12-3.
AT91SAM9263 JTAG Boundary Scan Register (Continued)
Bit
Number
Pin Name
Pin Type
188
187
INPUT
EBI0_D3
IN/OUT
OUTPUT
186
CONTROL
185
INPUT
184
EBI0_D4
IN/OUT
OUTPUT
183
CONTROL
182
INPUT
181
EBI0_D5
IN/OUT
OUTPUT
180
CONTROL
179
INPUT
178
EBI0_D6
IN/OUT
OUTPUT
177
CONTROL
176
INPUT
175
EBI0_D7
IN/OUT
OUTPUT
174
CONTROL
173
INPUT
172
EBI0_D8
IN/OUT
OUTPUT
171
CONTROL
170
INPUT
169
EBI0_D9
IN/OUT
OUTPUT
168
CONTROL
167
INPUT
166
EBI0_D10
IN/OUT
OUTPUT
165
CONTROL
164
INPUT
163
EBI0_D11
IN/OUT
OUTPUT
162
CONTROL
161
INPUT
160
EBI0_D12
IN/OUT
OUTPUT
159
CONTROL
158
INPUT
157
156
86
Associated
BSR Cells
EBI0_D13
IN/OUT
OUTPUT
CONTROL
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Table 12-3.
Bit
Number
AT91SAM9263 JTAG Boundary Scan Register (Continued)
Pin Name
Pin Type
155
154
Associated
BSR Cells
INPUT
EBI0_D14
IN/OUT
OUTPUT
153
CONTROL
152
INPUT
151
EBI0_D15
IN/OUT
OUTPUT
150
CONTROL
149
INPUT
148
PD5
IN/OUT
OUTPUT
147
CONTROL
146
INPUT
145
PD6
IN/OUT
OUTPUT
144
CONTROL
143
INPUT
142
PD12
IN/OUT
OUTPUT
141
CONTROL
140
INPUT
139
PD7
IN/OUT
OUTPUT
138
CONTROL
137
INPUT
136
PD8
IN/OUT
OUTPUT
135
CONTROL
134
INPUT
133
PD9
IN/OUT
OUTPUT
132
CONTROL
131
INPUT
130
PD10
IN/OUT
OUTPUT
129
CONTROL
128
INPUT
127
PD11
IN/OUT
OUTPUT
126
CONTROL
125
INPUT
124
123
PD13
IN/OUT
OUTPUT
CONTROL
87
6249B–ATARM–14-Dec-06
Table 12-3.
AT91SAM9263 JTAG Boundary Scan Register (Continued)
Bit
Number
Pin Name
Pin Type
122
121
INPUT
PD14
IN/OUT
OUTPUT
120
CONTROL
119
INPUT
118
PD15
IN/OUT
OUTPUT
117
CONTROL
116
INPUT
115
PD16
IN/OUT
OUTPUT
114
CONTROL
113
INPUT
112
PD17
IN/OUT
OUTPUT
111
CONTROL
110
INPUT
109
PD18
IN/OUT
OUTPUT
108
CONTROL
107
INPUT
106
PD19
IN/OUT
OUTPUT
105
CONTROL
104
INPUT
103
PD20
IN/OUT
OUTPUT
102
CONTROL
101
INPUT
100
PD21
IN/OUT
OUTPUT
99
CONTROL
98
INPUT
97
PD22
IN/OUT
OUTPUT
96
CONTROL
95
INPUT
94
PD23
IN/OUT
OUTPUT
93
CONTROL
92
INPUT
91
90
88
Associated
BSR Cells
PD24
IN/OUT
OUTPUT
CONTROL
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Table 12-3.
Bit
Number
AT91SAM9263 JTAG Boundary Scan Register (Continued)
Pin Name
Pin Type
89
88
Associated
BSR Cells
INPUT
PD25
IN/OUT
OUTPUT
87
CONTROL
86
INPUT
85
PD26
IN/OUT
OUTPUT
84
CONTROL
83
INPUT
82
PD27
IN/OUT
OUTPUT
81
CONTROL
80
INPUT
79
PD28
IN/OUT
OUTPUT
78
CONTROL
77
INPUT
76
PD29
IN/OUT
OUTPUT
75
CONTROL
74
INPUT
73
PD30
IN/OUT
OUTPUT
72
CONTROL
71
INPUT
70
PD31
IN/OUT
OUTPUT
69
CONTROL
68
INPUT
67
PE0
IN/OUT
OUTPUT
66
CONTROL
65
INPUT
64
PE1
IN/OUT
OUTPUT
63
CONTROL
62
INPUT
61
PE2
IN/OUT
OUTPUT
60
CONTROL
59
INPUT
58
57
PE3
IN/OUT
OUTPUT
CONTROL
89
6249B–ATARM–14-Dec-06
Table 12-3.
AT91SAM9263 JTAG Boundary Scan Register (Continued)
Bit
Number
Pin Name
Pin Type
56
55
INPUT
PE4
IN/OUT
OUTPUT
54
CONTROL
53
INPUT
52
PE5
IN/OUT
OUTPUT
51
CONTROL
50
INPUT
49
PE6
IN/OUT
OUTPUT
48
CONTROL
47
INPUT
46
PE7
IN/OUT
OUTPUT
45
CONTROL
44
INPUT
43
PE8
IN/OUT
OUTPUT
42
CONTROL
41
INPUT
40
PE9
IN/OUT
OUTPUT
39
CONTROL
38
INPUT
37
PE10
IN/OUT
OUTPUT
36
CONTROL
35
INPUT
34
PE11
IN/OUT
OUTPUT
33
CONTROL
32
INPUT
31
PE12
IN/OUT
OUTPUT
30
CONTROL
29
INPUT
28
PE13
IN/OUT
OUTPUT
27
CONTROL
26
INPUT
25
24
90
Associated
BSR Cells
PE14
IN/OUT
OUTPUT
CONTROL
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Table 12-3.
Bit
Number
AT91SAM9263 JTAG Boundary Scan Register (Continued)
Pin Name
Pin Type
23
22
Associated
BSR Cells
INPUT
PE15
IN/OUT
OUTPUT
21
CONTROL
20
INPUT
19
PE16
IN/OUT
OUTPUT
18
CONTROL
17
INPUT
16
PE17
IN/OUT
OUTPUT
15
CONTROL
14
INPUT
13
PE18
IN/OUT
OUTPUT
12
CONTROL
11
INPUT
10
PE19
IN/OUT
OUTPUT
09
CONTROL
08
INPUT
07
PA16
IN/OUT
OUTPUT
06
CONTROL
05
INPUT
04
PA17
IN/OUT
OUTPUT
03
CONTROL
02
INPUT
01
00
PA18
IN/OUT
OUTPUT
CONTROL
91
6249B–ATARM–14-Dec-06
12.5.7
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
MANUFACTURER IDENTITY
3
2
1
0
1
• MANUFACTURER IDENTITY[11:1]
Set to 0x01F.
Bit[0] Required by IEEE Std. 1149.1.
Set to 0x1.
JTAG ID Code value is 0x05B0_C03F.
• PART NUMBER[27:12]: Product Part Number
Product part Number is 0x5B0C
• VERSION[31:28]: Product Version Number
Set to 0x0.
92
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
13. AT91SAM9263 Boot Program
13.1
Description
The Boot Program integrates different programs permitting download and/or upload into the
different memories of the product.
First, it initializes the Debug Unit serial port (DBGU) and the USB Device Port.
Then the SD Card Boot program is executed. It looks for a boot.bin file in the root directory of
a FAT12/16/32 formatted SD Card. If such a file 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 the SD Card is not formatted or if boot.bin file is not found, NANDFlash Boot program is then
executed. First, as for SD Card Boot part, it looks for a boot.bin file in the root directory of a
FAT12/16/32 formatted NANDFlash. If such a file 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 the NANDFlash is not formatted, the NANDFlash Boot program looks for a sequence of
seven valid ARM exception vectors. If such a 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 DataFlash® Boot program is executed. It looks
for a sequence of seven valid ARM exception vectors in a DataFlash connected to the SPI. All
these vectors must be B-branch or LDR load register instructions except for the sixth vector.
This vector is used to store the size of the image to download.
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 boot.bin file is found, SAM-BA™ Boot is then executed. It waits for transactions either on
the USB device, or on the DBGU serial port.
13.2
Flow Diagram
The Boot Program implements the algorithm in Figure 13-1.
93
6249B–ATARM–14-Dec-06
Figure 13-1. Boot Program Algorithm Flow Diagram
Start
Main Oscillator Bypass
No
Enable
Main Oscillator
Yes
Download from
SD Card (MCI)
Run
SD Card Boot
Yes
Download from
NandFlash
Run
NandFlash Boot
Yes
Download from
DataFlash (NPCS0)
Run
DataFlash Boot
Yes
Input Frequency
Table
SD Card Boot
No
Timeout < 1 s
NandFlash Boot
No
Timeout < 1 s
SPI DataFlash Boot
No
No
Timeout < 1 s
USB Enumeration
Successful ?
No
Character(s) received
on DBGU ?
SAM-BA Boot
Yes
Run SAM-BA Boot
94
Yes
Run SAM-BA Boot
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
13.3
Device Initialization
Initialization follows the steps described below:
1. Stack setup for ARM supervisor mode
2. External Clock Detection
3. Switch Master Clock on Main Oscillator
4. C variable initialization
5. Main oscillator frequency detection
6. 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 13-1 defines the crystals supported by the Boot Program.
Table 13-1.
Crystals Supported by Software Auto-detection (MHz)
3.0
3.2768
3.6864
3.84
4.0
4.433619
4.608
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
7. Initialization of the DBGU serial port (115200 bauds, 8, N, 1)
8. Enable the User Reset
9. Jump to SD Card Boot sequence. If SD Card Boot succeeds, perform a remap and
jump to 0x0.
10. Jump to NANDFlash Boot sequence. If NANDFlash Boot succeeds, perform a remap
and jump to 0x0.
11. Jump to DataFlash Boot sequence through NPCS0. If DataFlash Boot succeeds, perform a remap and jump to 0x0.
12. Activation of the Instruction Cache
13. Jump to SAM-BA Boot sequence
14. Disable the WatchDog
15. Initialization of the USB Device Port
Figure 13-2. Remap Action after Download Completion
0x0000_0000
0x0000_0000
Internal
ROM
Internal
SRAM
REMAP
0x0030_0000
0x0040_0000
Internal
SRAM
Internal
ROM
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13.4
DataFlash Boot
The DataFlash Boot program searches for a valid application in the SPI DataFlash memory. 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 second-level bootloader.
All the calls to functions are PC relative and do not use absolute addresses.
After reset, the code in internal ROM is mapped at both addresses 0x0000_0000 and 0x0010_0000:
400000
ea000006
B
0x20
00
ea000006
B
0x20
400004
eafffffe
B
0x04
04
eafffffe
B
0x04
400008
ea00002f
B
_main
08
ea00002f
B
_main
40000c
eafffffe
B
0x0c
0c
eafffffe
B
0x0c
400010
eafffffe
B
0x10
10
eafffffe
B
0x10
400014
eafffffe
B
0x14
14
eafffffe
B
0x14
400018
eafffffe
B
0x18
18
eafffffe
B
0x18
40001c
eafffffe
B
0x1c
1c
eafffffe
B
0x1c
13.4.1
Valid Image Detection
The DataFlash Boot software looks for a valid application by analyzing the first 28 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. The user must
replace this vector with his own vector (see ”Structure of ARM Vector 6” on page 96).
Figure 13-3. LDR Opcode
31
1
28 27
1
1
0
1
24 23
1
I
0
1
P
U
20 19
1
W
0
16 15
Rn
12 11
0
Rd
Figure 13-4. B Opcode
31
1
28 27
1
1
0
1
24 23
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
13.4.2
Structure of ARM Vector 6
The ARM exception vector 6 is used to store information needed by the DataFlash boot program. This information is described below.
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Figure 13-5. Structure of the ARM Vector 6
31
0
Size of the code to download in bytes
13.4.2.1
Example
An example of valid vectors follows:
00
ea000006
B
0x20
04
eafffffe
B
0x04
08
ea00002f
B
_main
0c
eafffffe
B
0x0c
10
eafffffe
B
0x10
14
00001234
B
0x14
18
eafffffe
B
0x18
<- Code size = 4660 bytes
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.
13.4.3
DataFlash Boot Sequence
The DataFlash boot program performs device initialization followed by the download
procedure.
The DataFlash boot program supports all Atmel DataFlash devices. Table 13-2 summarizes
the parameters to include in the ARM vector 6 for all devices.
Table 13-2.
Device
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
The DataFlash has a Status Register that determines all the parameters required to access
the device. The DataFlash boot is configured to be compatible with the future design of the
DataFlash.
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Figure 13-6. Serial DataFlash Download
Start
Send status command
Is status OK ?
No
Jump to next boot
solution
Yes
Read the first 7 instructions (28 bytes).
Decode the sixth ARM vector
7 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
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13.5
SD Card Boot
The SD Card Boot program searches for a valid application in the SD Card memory.
It looks for a boot.bin file in the root directory of a FAT12/16/32 formatted SD Card. If a valid
file 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.
13.6
NANDFlash Boot
The NANDFlash Boot program searches for a valid application in the NANDFlash memory.
First, it looks for a boot.bin file in the root directory of a FAT12/16/32 formatted NANDFlash. If
a valid file 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.
If NANDFlash is not formatted, the NANDFlash Boot program searches for a valid application
in the NANDFlash memory. If a valid application is found, this application is loaded into internal
SRAM and executed by branching at address 0x0000_0000 after remap. See ”DataFlash
Boot” on page 96 for more information on Valid Image Detection.
13.6.1
13.7
Supported NANDFlash Devices
Any 8 or 16-bit NANDFlash devices are supported.
SAM-BA Boot
If no valid DataFlash device has been found during the DataFlash boot sequence, the SAMBA boot program is performed.
The SAM-BA boot principle is to:
– Check if USB Device enumeration has occured.
– Check if character(s) have been received on the DBGU.
– Once the communication interface is identified, the application runs in an infinite
loop waiting for different commands as in Table 13-3.
Table 13-3.
Commands Available through the SAM-BA Boot
Command
Action
Argument(s)
Example
O
write a byte
Address, Value#
O200001,CA#
o
read a byte
Address,#
o200001,#
H
write a half word
Address, Value#
H200002,CAFE#
h
read a half word
Address,#
h200002,#
W
write a word
Address, Value#
W200000,CAFEDECA#
w
read a word
Address,#
w200000,#
S
send a file
Address,#
S200000,#
R
receive a file
Address, NbOfBytes#
R200000,1234#
G
go
Address#
G200200#
V
display version
No argument
V#
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• Write commands: Write a byte (O), a halfword (H) or a word (W) to the target.
– Address: Address in hexadecimal.
– Value: Byte, halfword or word to write in hexadecimal.
– Output: ‘>’.
• Read commands: Read a byte (o), a halfword (h) or a word (w) from the target.
– Address: Address in hexadecimal
– Output: The byte, halfword or word read in hexadecimal following by ‘>’
• Send a file (S): Send a file to a specified address
– Address: Address in hexadecimal
– Output: ‘>’.
Note:
There is a time-out on this command which is reached when the prompt ‘>’ appears before the
end of the command execution.
• Receive a file (R): Receive data into a file from a specified address
– Address: Address in hexadecimal
– NbOfBytes: Number of bytes in hexadecimal to receive
– Output: ‘>’
• Go (G): Jump to a specified address and execute the code
– Address: Address to jump in hexadecimal
– Output: ‘>’
• Get Version (V): Return the SAM-BA boot version
– Output: ‘>’
13.7.1
DBGU Serial Port
Communication is performed through the DBGU serial port initialized to 115200 Baud, 8, n, 1.
The Send and Receive File commands use the Xmodem protocol to communicate. 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. In all cases, the
size of the binary file must be lower than the SRAM size because the Xmodem protocol
requires some SRAM memory to work.
13.7.2
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 13-7 shows a transmission using this protocol.
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Figure 13-7. 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
13.7.3
USB Device Port
A 48 MHz USB clock is necessary to use the USB Device port. It has been programmed earlier in the device initialization procedure with PLLB configuration.
The device uses the USB communication device class (CDC) drivers to take advantage of the
installed PC RS-232 software to talk over the USB. The CDC class is implemented in all
releases of Windows®, from Windows 98SE to Windows XP. The CDC document, available at
www.usb.org, describes a way to implement devices such as ISDN modems and virtual COM
ports.
The Vendor ID is Atmel’s vendor ID 0x03EB. The product ID is 0x6124. These references are
used by the host operating system to mount the correct driver. On Windows systems, the INF
files contain the correspondence between vendor ID and product ID.
Atmel provides an INF example to see the device as a new serial port and also provides
another custom driver used by the SAM-BA application: atm6124.sys. Refer to the document
“USB Basic Application”, literature number 6123, for more details.
13.7.3.1
Enumeration Process
The USB protocol is a master/slave protocol. This is the host that starts the enumeration sending requests to the device through the control endpoint. The device handles standard requests
as defined in the USB Specification.
Table 13-4.
Handled Standard Requests
Request
Definition
GET_DESCRIPTOR
Returns the current device configuration value.
SET_ADDRESS
Sets the device address for all future device access.
SET_CONFIGURATION
Sets the device configuration.
GET_CONFIGURATION
Returns the current device configuration value.
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Table 13-4.
Handled Standard Requests (Continued)
Request
Definition
GET_STATUS
Returns status for the specified recipient.
SET_FEATURE
Used to set or enable a specific feature.
CLEAR_FEATURE
Used to clear or disable a specific feature.
The device also handles some class requests defined in the CDC class.
Table 13-5.
Handled Class Requests
Request
Definition
SET_LINE_CODING
Configures DTE rate, stop bits, parity and number of
character bits.
GET_LINE_CODING
Requests current DTE rate, stop bits, parity and number
of character bits.
SET_CONTROL_LINE_STATE
RS-232 signal used to tell the DCE device the DTE
device is now present.
Unhandled requests are STALLed.
13.7.3.2
Communication Endpoints
There are two communication endpoints and endpoint 0 is used for the enumeration process.
Endpoint 1 is a 64-byte Bulk OUT endpoint and endpoint 2 is a 64-byte Bulk IN endpoint.
SAM-BA Boot commands are sent by the host through the endpoint 1. If required, the message is split by the host into several data payloads by the host driver.
If the command requires a response, the host can send IN transactions to pick up the
response.
13.8
Hardware and Software Constraints
• The SD Card, NANDFlash and DataFlash downloaded code size must be inferior to 72 K
bytes.
• The code is always downloaded from the DataFlash or NANDFlash device address
0x0000_0000 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 DataFlash must be connected to NPCS0 of the SPI.
• USB requirements:
– Crystal or Input Frequencies supported by Software Auto-detection. See Table 131 on page 95 for more informations.
The MCI, the SPI and NandFlash 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 peripherals output pins and the connected devices may appear.
To assure correct functionality, it is recommended to plug in critical devices to other pins.
Table 13-6 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 less than 1 second if no correct boot
program is found.
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For the DataFlash driven by the SPCK signal at 8 MHz, the time to download 72 KBytes is
reduced to 200 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 13-6.
Pins Driven during Boot Program Execution
Peripheral
Pin
PIO Line
MCI1
MCCK
PIOA6
MCI1
MCCDA
PIOA7
MCI1
MCDA0
PIOA8
MCI1
MCDA1
PIOA9
MCI1
MCDA2
PIOA10
MCI1
MCDA3
PIOA11
SPI0
MOSI
PIOA1
SPI0
MISO
PIOA0
SPI0
SPCK
PIOA2
SPI0
NPCS0
PIOA5
PIOD
NANDCS
PIOD15
DBGU
DRXD
PIOC30
DBGU
DTXD
PIOC31
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14. Reset Controller (RSTC)
14.1
Description
The Reset Controller (RSTC), based on power-on reset cells, handles all the resets of the system without any external components. It reports which reset occurred last.
The Reset Controller also drives independently or simultaneously the external reset and the
peripheral and processor resets.
14.2
Block Diagram
Figure 14-1. Reset Controller Block Diagram
Reset Controller
Main Supply
POR
Backup Supply
POR
rstc_irq
Startup
Counter
Reset
State
Manager
proc_nreset
user_reset
NRST
nrst_out
NRST
Manager
periph_nreset
exter_nreset
backup_neset
WDRPROC
wd_fault
SLCK
14.3
14.3.1
Functional Description
Reset Controller Overview
The Reset Controller is made up of an NRST Manager, a Startup Counter and a Reset State
Manager. It runs at Slow Clock and generates the following reset signals:
• proc_nreset: Processor reset line. It also resets the Watchdog Timer.
• backup_nreset: Affects all the peripherals powered by VDDBU.
• periph_nreset: Affects the whole set of embedded peripherals.
• nrst_out: Drives the NRST pin.
These reset signals are asserted by the Reset Controller, either on external events or on software action. The Reset State Manager controls the generation of reset signals and provides a
signal to the NRST Manager when an assertion of the NRST pin is required.
The NRST Manager shapes the NRST assertion during a programmable time, thus controlling
external device resets.
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The startup counter waits for the complete crystal oscillator startup. The wait delay is given by
the crystal oscillator startup time maximum value that can be found in the section Crystal Oscillator Characteristics in the Electrical Characteristics section of the product documentation.
The Reset Controller Mode Register (RSTC_MR), allowing the configuration of the Reset Controller, is powered with VDDBU, so that its configuration is saved as long as VDDBU is on.
14.3.2
NRST Manager
The NRST Manager samples the NRST input pin and drives this pin low when required by the
Reset State Manager. Figure 14-2 shows the block diagram of the NRST Manager.
Figure 14-2. NRST Manager
RSTC_MR
URSTIEN
RSTC_SR
URSTS
NRSTL
rstc_irq
RSTC_MR
URSTEN
Other
interrupt
sources
user_reset
NRST
RSTC_MR
ERSTL
nrst_out
14.3.2.1
External Reset Timer
exter_nreset
NRST Signal or Interrupt
The NRST Manager samples the NRST pin at Slow Clock speed. When the line is detected low,
a User Reset is reported to the Reset State Manager.
However, the NRST Manager can be programmed to not trigger a reset when an assertion of
NRST occurs. Writing the bit URSTEN at 0 in RSTC_MR disables the User Reset trigger.
The level of the pin NRST can be read at any time in the bit NRSTL (NRST level) in RSTC_SR.
As soon as the pin NRST is asserted, the bit URSTS in RSTC_SR is set. This bit clears only
when RSTC_SR is read.
The Reset Controller can also be programmed to generate an interrupt instead of generating a
reset. To do so, the bit URSTIEN in RSTC_MR must be written at 1.
14.3.2.2
NRST External Reset Control
The Reset State Manager asserts the signal ext_nreset to assert the NRST pin. When this
occurs, the “nrst_out” signal is driven low by the NRST Manager for a time programmed by the
field ERSTL in RSTC_MR. This assertion duration, named EXTERNAL_RESET_LENGTH, lasts
2(ERSTL+1) Slow Clock cycles. This gives the approximate duration of an assertion between 60 µs
and 2 seconds. Note that ERSTL at 0 defines a two-cycle duration for the NRST pulse.
This feature allows the Reset Controller to shape the NRST pin level, and thus to guarantee that
the NRST line is driven low for a time compliant with potential external devices connected on the
system reset.
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As the field is within RSTC_MR, which is backed-up, this field can be used to shape the system
power-up reset for devices requiring a longer startup time than the Slow Clock Oscillator.
14.3.3
Reset States
The Reset State Manager handles the different reset sources and generates the internal reset
signals. It reports the reset status in the field RSTTYP of the Status Register (RSTC_SR). The
update of the field RSTTYP is performed when the processor reset is released.
14.3.3.1
General Reset
A general reset occurs when VDDBU is powered on. The backup supply POR cell output rises
and is filtered with a Startup Counter, which operates at Slow Clock. The purpose of this counter
is to make sure the Slow Clock oscillator is stable before starting up the device. The length of
startup time is hardcoded to comply with the Slow Clock Oscillator startup time.
After this time, the processor clock is released at Slow Clock and all the other signals remains
valid for 2 cycles for proper processor and logic reset. Then, all the reset signals are released
and the field RSTTYP in RSTC_SR reports a General Reset. As the RSTC_MR is reset, the
NRST line rises 2 cycles after the backup_nreset, as ERSTL defaults at value 0x0.
When VDDBU is detected low by the Backup Supply POR Cell, all resets signals are immediately asserted, even if the Main Supply POR Cell does not report a Main Supply shut down.
Figure 14-3 shows how the General Reset affects the reset signals.
Figure 14-3. General Reset State
SLCK
Any
Freq.
MCK
Backup Supply
POR output
Startup Time
backup_nreset
Processor Startup
= 3 cycles
proc_nreset
RSTTYP
XXX
0x0 = General Reset
XXX
periph_nreset
NRST
(nrst_out)
EXTERNAL RESET LENGTH
= 2 cycles
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14.3.3.2
Wake-up Reset
The Wake-up Reset occurs when the Main Supply is down. When the Main Supply POR output
is active, all the reset signals are asserted except backup_nreset. When the Main Supply powers up, the POR output is resynchronized on Slow Clock. The processor clock is then re-enabled
during 2 Slow Clock cycles, depending on the requirements of the ARM processor.
At the end of this delay, the processor and other reset signals rise. The field RSTTYP in
RSTC_SR is updated to report a Wake-up Reset.
The “nrst_out” remains asserted for EXTERNAL_RESET_LENGTH cycles. As RSTC_MR is
backed-up, the programmed number of cycles is applicable.
When the Main Supply is detected falling, the reset signals are immediately asserted. This transition is synchronous with the output of the Main Supply POR.
Figure 14-4. Wake-up State
SLCK
Any
Freq.
MCK
Main Supply
POR output
backup_nreset
Resynch.
2 cycles
proc_nreset
RSTTYP
Processor Startup
= 3 cycles
XXX
0x1 = WakeUp Reset
XXX
periph_nreset
NRST
(nrst_out)
EXTERNAL RESET LENGTH
= 4 cycles (ERSTL = 1)
Figure 14-5.
14.3.3.3
User Reset
The User Reset is entered when a low level is detected on the NRST pin and the bit URSTEN in
RSTC_MR is at 1. The NRST input signal is resynchronized with SLCK to insure proper behavior of the system.
The User Reset is entered as soon as a low level is detected on NRST. The Processor Reset
and the Peripheral Reset are asserted.
The User Reset is left when NRST rises, after a two-cycle resynchronization time and a threecycle processor startup. The processor clock is re-enabled as soon as NRST is confirmed high.
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When the processor reset signal is released, the RSTTYP field of the Status Register
(RSTC_SR) is loaded with the value 0x4, indicating a User Reset.
The NRST Manager guarantees that the NRST line is asserted for
EXTERNAL_RESET_LENGTH Slow Clock cycles, as programmed in the field ERSTL. However, if NRST does not rise after EXTERNAL_RESET_LENGTH because it is driven low
externally, the internal reset lines remain asserted until NRST actually rises.
Figure 14-6. User Reset State
SLCK
MCK
Any
Freq.
NRST
Resynch.
2 cycles
Resynch.
2 cycles
Processor Startup
= 3 cycles
proc_nreset
RSTTYP
Any
XXX
0x4 = User Reset
periph_nreset
NRST
(nrst_out)
>= EXTERNAL RESET LENGTH
14.3.3.4
Software Reset
The Reset Controller offers several commands used to assert the different reset signals. These
commands are performed by writing the Control Register (RSTC_CR) with the following bits at
1:
• PROCRST: Writing PROCRST at 1 resets the processor and the watchdog timer.
• PERRST: Writing PERRST at 1 resets all the embedded peripherals, including the memory
system, and, in particular, the Remap Command. The Peripheral Reset is generally used for
debug purposes.
• EXTRST: Writing EXTRST at 1 asserts low the NRST pin during a time defined by the field
ERSTL in the Mode Register (RSTC_MR).
The software reset is entered if at least one of these bits is set by the software. All these commands can be performed independently or simultaneously. The software reset lasts 2 Slow
Clock cycles.
The internal reset signals are asserted as soon as the register write is performed. This is
detected on the Master Clock (MCK). They are released when the software reset is left, i.e.; synchronously to SLCK.
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If EXTRST is set, the nrst_out signal is asserted depending on the programming of the field
ERSTL. However, the resulting falling edge on NRST does not lead to a User Reset.
If and only if the PROCRST bit is set, the Reset Controller reports the software status in the field
RSTTYP of the Status Register (RSTC_SR). Other Software Resets are not reported in
RSTTYP.
As soon as a software operation is detected, the bit SRCMP (Software Reset Command in
Progress) is set in the Status Register (RSTC_SR). It is cleared as soon as the software reset is
left. No other software reset can be performed while the SRCMP bit is set, and writing any value
in RSTC_CR has no effect.
Figure 14-7. Software Reset
SLCK
MCK
Any
Freq.
Write RSTC_CR
Resynch.
1 cycle
Processor Startup
= 3 cycles
proc_nreset
if PROCRST=1
RSTTYP
Any
XXX
0x3 = Software Reset
periph_nreset
if PERRST=1
NRST
(nrst_out)
if EXTRST=1
EXTERNAL RESET LENGTH
8 cycles (ERSTL=2)
SRCMP in RSTC_SR
14.3.3.5
Watchdog Reset
The Watchdog Reset is entered when a watchdog fault occurs. This state lasts 2 Slow Clock
cycles.
When in Watchdog Reset, assertion of the reset signals depends on the WDRPROC bit in
WDT_MR:
• If WDRPROC is 0, the Processor Reset and the Peripheral Reset are asserted. The NRST
line is also asserted, depending on the programming of the field ERSTL. However, the
resulting low level on NRST does not result in a User Reset state.
• If WDRPROC = 1, only the processor reset is asserted.
The Watchdog Timer is reset by the proc_nreset signal. As the watchdog fault always causes a
processor reset if WDRSTEN is set, the Watchdog Timer is always reset after a Watchdog
Reset, and the Watchdog is enabled by default and with a period set to a maximum.
When the WDRSTEN in WDT_MR bit is reset, the watchdog fault has no impact on the reset
controller.
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Figure 14-8. Watchdog Reset
SLCK
MCK
Any
Freq.
wd_fault
Processor Startup
= 3 cycles
proc_nreset
RSTTYP
Any
XXX
0x2 = Watchdog Reset
periph_nreset
Only if
WDRPROC = 0
NRST
(nrst_out)
EXTERNAL RESET LENGTH
8 cycles (ERSTL=2)
14.3.4
Reset State Priorities
The Reset State Manager manages the following priorities between the different reset sources,
given in descending order:
• Backup Reset
• Wake-up Reset
• Watchdog Reset
• Software Reset
• User Reset
Particular cases are listed below:
• When in User Reset:
– A watchdog event is impossible because the Watchdog Timer is being reset by the
proc_nreset signal.
– A software reset is impossible, since the processor reset is being activated.
• When in Software Reset:
– A watchdog event has priority over the current state.
– The NRST has no effect.
• When in Watchdog Reset:
– The processor reset is active and so a Software Reset cannot be programmed.
– A User Reset cannot be entered.
14.3.5
Reset Controller Status Register
The Reset Controller status register (RSTC_SR) provides several status fields:
111
6249B–ATARM–14-Dec-06
• RSTTYP field: This field gives the type of the last reset, as explained in previous sections.
• SRCMP bit: This field indicates that a Software Reset Command is in progress and that no
further software reset should be performed until the end of the current one. This bit is
automatically cleared at the end of the current software reset.
• NRSTL bit: The NRSTL bit of the Status Register gives the level of the NRST pin sampled on
each MCK rising edge.
• URSTS bit: A high-to-low transition of the NRST pin sets the URSTS bit of the RSTC_SR
register. This transition is also detected on the Master Clock (MCK) rising edge (see Figure
14-9). If the User Reset is disabled (URSTEN = 0) and if the interruption is enabled by the
URSTIEN bit in the RSTC_MR register, the URSTS bit triggers an interrupt. Reading the
RSTC_SR status register resets the URSTS bit and clears the interrupt.
Figure 14-9.
Reset Controller Status and Interrupt
MCK
read
RSTC_SR
Peripheral Access
2 cycle
resynchronization
2 cycle
resynchronization
NRST
NRSTL
URSTS
rstc_irq
if (URSTEN = 0) and
(URSTIEN = 1)
112
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AT91SAM9263 Preliminary
14.4
Reset Controller (RSTC) User Interface
Table 14-1.
Reset Controller (RSTC) Register Mapping
Offset
Register
Name
0x00
Control Register
0x04
0x08
Note:
Back-up Reset
Value
Access
Reset Value
RSTC_CR
Write-only
-
Status Register
RSTC_SR
Read-only
0x0000_0001
0x0000_0000
Mode Register
RSTC_MR
Read/Write
-
0x0000_0000
1. The reset value of RSTC_SR either reports a General Reset or a Wake-up Reset depending on last rising power supply.
113
6249B–ATARM–14-Dec-06
14.4.1
Reset Controller Control Register
Register Name:
RSTC_CR
Access Type:
31
Write-only
30
29
28
27
26
25
24
KEY
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
–
14
–
13
–
12
–
11
–
10
–
9
8
–
7
–
6
–
5
–
4
–
3
EXTRST
2
PERRST
1
–
0
PROCRST
• PROCRST: Processor Reset
0 = No effect.
1 = If KEY is correct, resets the processor.
• PERRST: Peripheral Reset
0 = No effect.
1 = If KEY is correct, resets the peripherals.
• EXTRST: External Reset
0 = No effect.
1 = If KEY is correct, asserts the NRST pin.
• KEY: Password
Should be written at value 0xA5. Writing any other value in this field aborts the write operation.
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14.4.2
Reset Controller Status Register
Register Name:
RSTC_SR
Access Type:
Read-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
SRCMP
16
NRSTL
15
–
14
–
13
–
12
–
11
–
10
9
RSTTYP
8
7
–
6
–
5
–
4
–
3
–
2
–
1
0
URSTS
• URSTS: User Reset Status
0 = No high-to-low edge on NRST happened since the last read of RSTC_SR.
1 = At least one high-to-low transition of NRST has been detected since the last read of RSTC_SR.
• RSTTYP: Reset Type
Reports the cause of the last processor reset. Reading this RSTC_SR does not reset this field.
RSTTYP
Reset Type
Comments
0
0
0
General Reset
Both VDDCORE and VDDBU rising
0
0
1
Wake Up Reset
VDDCORE rising
0
1
0
Watchdog Reset
Watchdog fault occurred
0
1
1
Software Reset
Processor reset required by the software
1
0
0
User Reset
NRST pin detected low
• NRSTL: NRST Pin Level
Registers the NRST Pin Level at Master Clock (MCK).
• SRCMP: Software Reset Command in Progress
0 = No software command is being performed by the reset controller. The reset controller is ready for a software command.
1 = A software reset command is being performed by the reset controller. The reset controller is busy.
115
6249B–ATARM–14-Dec-06
14.4.3
Reset Controller Mode Register
Register Name:
RSTC_MR
Access Type:
31
Read/Write
30
29
28
27
26
25
24
KEY
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
15
–
14
–
13
–
12
–
11
10
9
8
7
–
6
–
5
4
URSTIEN
3
–
1
–
0
URSTEN
ERSTL
2
–
• URSTEN: User Reset Enable
0 = The detection of a low level on the pin NRST does not generate a User Reset.
1 = The detection of a low level on the pin NRST triggers a User Reset.
• URSTIEN: User Reset Interrupt Enable
0 = USRTS bit in RSTC_SR at 1 has no effect on rstc_irq.
1 = USRTS bit in RSTC_SR at 1 asserts rstc_irq if URSTEN = 0.
• ERSTL: External Reset Length
This field defines the external reset length. The external reset is asserted during a time of 2(ERSTL+1) Slow Clock cycles. This
allows assertion duration to be programmed between 60 µs and 2 seconds.
• KEY: Password
Should be written at value 0xA5. Writing any other value in this field aborts the write operation.
116
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AT91SAM9263 Preliminary
15. Real-time Timer (RTT)
15.1
Overview
The Real-time Timer is built around a 32-bit counter and used to count elapsed seconds. It
generates a periodic interrupt and/or triggers an alarm on a programmed value.
15.2
Block Diagram
Figure 15-1. Real-time Timer
RTT_MR
RTTRST
RTT_MR
RTPRES
RTT_MR
SLCK
RTTINCIEN
reload
16-bit
Divider
set
0
RTT_MR
RTTRST
RTTINC
RTT_SR
1
reset
0
rtt_int
32-bit
Counter
read
RTT_SR
RTT_MR
ALMIEN
RTT_VR
reset
CRTV
RTT_SR
ALMS
set
rtt_alarm
=
RTT_AR
15.3
ALMV
Functional Description
The Real-time Timer is used to count elapsed seconds. It is built around a 32-bit counter fed
by Slow Clock divided by a programmable 16-bit value. The value can be programmed in the
field RTPRES of the Real-time Mode Register (RTT_MR).
Programming RTPRES at 0x00008000 corresponds to feeding the real-time counter with a 1
Hz signal (if the Slow Clock is 32.768 Hz). The 32-bit counter can count up to 232 seconds,
corresponding to more than 136 years, then roll over to 0.
The Real-time Timer can also be used as a free-running timer with a lower time-base. The
best accuracy is achieved by writing RTPRES to 3. Programming RTPRES to 1 or 2 is possible, but may result in losing status events because the status register is cleared two Slow
Clock cycles after read. Thus if the RTT is configured to trigger an interrupt, the interrupt
occurs during 2 Slow Clock cycles after reading RTT_SR. To prevent several executions of
the interrupt handler, the interrupt must be disabled in the interrupt handler and re-enabled
when the status register is clear.
117
6249B–ATARM–14-Dec-06
The Real-time Timer value (CRTV) can be read at any time in the register RTT_VR (Real-time
Value Register). As this value can be updated asynchronously from the Master Clock, it is
advisable to read this register twice at the same value to improve accuracy of the returned
value.
The current value of the counter is compared with the value written in the alarm register
RTT_AR (Real-time Alarm Register). If the counter value matches the alarm, the bit ALMS in
RTT_SR is set. The alarm register is set to its maximum value, corresponding to
0xFFFF_FFFF, after a reset.
The bit RTTINC in RTT_SR is set each time the Real-time Timer counter is incremented. This
bit can be used to start a periodic interrupt, the period being one second when the RTPRES is
programmed with 0x8000 and Slow Clock equal to 32.768 Hz.
Reading the RTT_SR status register resets the RTTINC and ALMS fields.
Writing the bit RTTRST in RTT_MR immediately reloads and restarts the clock divider with the
new programmed value. This also resets the 32-bit counter.
Note:
Because of the asynchronism between the Slow Clock (SCLK) and the System Clock (MCK):
1) The restart of the counter and the reset of the RTT_VR current value register is effective only
2 slow clock cycles after the write of the RTTRST bit in the RTT_MR register.
2) The status register flags reset is taken into account only 2 slow clock cycles after the read of
the RTT_SR (Status Register).
Figure 15-2. RTT Counting
APB cycle
APB cycle
MCK
RTPRES - 1
Prescaler
0
RTT
0
...
ALMV-1
ALMV
ALMV+1
ALMV+2
ALMV+3
RTTINC (RTT_SR)
ALMS (RTT_SR)
APB Interface
read RTT_SR
118
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AT91SAM9263 Preliminary
15.4
15.4.1
Real-time Timer (RTT) User Interface
Register Mapping
Table 15-1.
Real-time Timer Register Mapping
Offset
Register
Name
Access
Reset Value
0x00
Mode Register
RTT_MR
Read/Write
0x0000_8000
0x04
Alarm Register
RTT_AR
Read/Write
0xFFFF_FFFF
0x08
Value Register
RTT_VR
Read-only
0x0000_0000
0x0C
Status Register
RTT_SR
Read-only
0x0000_0000
119
6249B–ATARM–14-Dec-06
15.4.2
Real-time Timer Mode Register
Register Name:
RTT_MR
Access Type:
Read/Write
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
RTTRST
17
RTTINCIEN
16
ALMIEN
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. RTPRES is defined as follows:
RTPRES = 0: The prescaler period is equal to 216
RTPRES ≠ 0: The prescaler period is equal to RTPRES.
• ALMIEN: Alarm Interrupt Enable
0 = The bit ALMS in RTT_SR has no effect on interrupt.
1 = The bit ALMS in RTT_SR asserts interrupt.
• RTTINCIEN: Real-time Timer Increment Interrupt Enable
0 = The bit RTTINC in RTT_SR has no effect on interrupt.
1 = The bit RTTINC in RTT_SR asserts interrupt.
• RTTRST: Real-time Timer Restart
1 = Reloads and restarts the clock divider with the new programmed value. This also resets the 32-bit counter.
120
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AT91SAM9263 Preliminary
15.4.3
Real-time Timer Alarm Register
Register Name:
RTT_AR
Access Type:
Read/Write
31
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
ALMV
23
22
21
20
ALMV
15
14
13
12
ALMV
7
6
5
4
ALMV
• ALMV: Alarm Value
Defines the alarm value (ALMV+1) compared with the Real-time Timer.
15.4.4
Real-time Timer Value Register
Register Name:
RTT_VR
Access Type:
Read-only
31
30
29
28
CRTV
23
22
21
20
CRTV
15
14
13
12
CRTV
7
6
5
4
CRTV
• CRTV: Current Real-time Value
Returns the current value of the Real-time Timer.
121
6249B–ATARM–14-Dec-06
15.4.5
Real-time Timer Status Register
Register Name:
RTT_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
RTTINC
0
ALMS
• ALMS: Real-time Alarm Status
0 = The Real-time Alarm has not occured since the last read of RTT_SR.
1 = The Real-time Alarm occured since the last read of RTT_SR.
• RTTINC: Real-time Timer Increment
0 = The Real-time Timer has not been incremented since the last read of the RTT_SR.
1 = The Real-time Timer has been incremented since the last read of the RTT_SR.
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AT91SAM9263 Preliminary
16. Periodic Interval Timer (PIT)
16.1
Overview
The Periodic Interval Timer (PIT) provides the operating system’s scheduler interrupt. It is
designed to offer maximum accuracy and efficient management, even for systems with long
response time.
16.2
Block Diagram
Figure 16-1. Periodic Interval Timer
PIT_MR
PIV
=?
PIT_MR
PITIEN
set
0
PIT_SR
PITS
pit_irq
reset
0
MCK
Prescaler
0
0
1
12-bit
Adder
1
read PIT_PIVR
20-bit
Counter
MCK/16
CPIV
PIT_PIVR
CPIV
PIT_PIIR
PICNT
PICNT
123
6249B–ATARM–14-Dec-06
16.3
Functional Description
The Periodic Interval Timer aims at providing periodic interrupts for use by operating systems.
The PIT provides a programmable overflow counter and a reset-on-read feature. It is built
around two counters: a 20-bit CPIV counter and a 12-bit PICNT counter. Both counters work at
Master Clock /16.
The first 20-bit CPIV counter increments from 0 up to a programmable overflow value set in the
field PIV of the Mode Register (PIT_MR). When the counter CPIV reaches this value, it resets to
0 and increments the Periodic Interval Counter, PICNT. The status bit PITS in the Status Register (PIT_SR) rises and triggers an interrupt, provided the interrupt is enabled (PITIEN in
PIT_MR).
Writing a new PIV value in PIT_MR does not reset/restart the counters.
When CPIV and PICNT values are obtained by reading the Periodic Interval Value Register
(PIT_PIVR), the overflow counter (PICNT) is reset and the PITS is cleared, thus acknowledging
the interrupt. The value of PICNT gives the number of periodic intervals elapsed since the last
read of PIT_PIVR.
When CPIV and PICNT values are obtained by reading the Periodic Interval Image Register
(PIT_PIIR), there is no effect on the counters CPIV and PICNT, nor on the bit PITS. For example, a profiler can read PIT_PIIR without clearing any pending interrupt, whereas a timer
interrupt clears the interrupt by reading PIT_PIVR.
The PIT may be enabled/disabled using the PITEN bit in the PIT_MR register (disabled on
reset). The PITEN bit only becomes effective when the CPIV value is 0. Figure 16-2 illustrates
the PIT counting. After the PIT Enable bit is reset (PITEN= 0), the CPIV goes on counting until
the PIV value is reached, and is then reset. PIT restarts counting, only if the PITEN is set again.
The PIT is stopped when the core enters debug state.
124
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AT91SAM9263 Preliminary
Figure 16-2. Enabling/Disabling PIT with PITEN
APB cycle
APB cycle
MCK
15
restarts MCK Prescaler
MCK Prescaler 0
PITEN
CPIV
PICNT
0
1
PIV - 1
0
PIV
1
0
1
0
PITS (PIT_SR)
APB Interface
read PIT_PIVR
125
6249B–ATARM–14-Dec-06
16.4
Periodic Interval Timer (PIT) User Interface
Table 16-1.
Periodic Interval Timer (PIT) Register Mapping
Offset
Register
Name
Access
Reset Value
0x00
Mode Register
PIT_MR
Read/Write
0x000F_FFFF
0x04
Status Register
PIT_SR
Read-only
0x0000_0000
0x08
Periodic Interval Value Register
PIT_PIVR
Read-only
0x0000_0000
0x0C
Periodic Interval Image Register
PIT_PIIR
Read-only
0x0000_0000
126
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
16.4.1
Periodic Interval Timer Mode Register
Register Name:
PIT_MR
Access Type:
Read/Write
31
–
30
–
29
–
28
–
27
–
26
–
25
PITIEN
24
PITEN
23
–
22
–
21
–
20
–
19
18
17
16
15
14
13
12
PIV
11
10
9
8
3
2
1
0
PIV
7
6
5
4
PIV
• PIV: Periodic Interval Value
Defines the value compared with the primary 20-bit counter of the Periodic Interval Timer (CPIV). The period is equal to
(PIV + 1).
• PITEN: Period Interval Timer Enabled
0 = The Periodic Interval Timer is disabled when the PIV value is reached.
1 = The Periodic Interval Timer is enabled.
• PITIEN: Periodic Interval Timer Interrupt Enable
0 = The bit PITS in PIT_SR has no effect on interrupt.
1 = The bit PITS in PIT_SR asserts interrupt.
16.4.2
Periodic Interval Timer Status Register
Register Name:
PIT_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
PITS
• PITS: Periodic Interval Timer Status
0 = The Periodic Interval timer has not reached PIV since the last read of PIT_PIVR.
1 = The Periodic Interval timer has reached PIV since the last read of PIT_PIVR.
127
6249B–ATARM–14-Dec-06
16.4.3
Periodic Interval Timer Value Register
Register Name:
PIT_PIVR
Access Type:
Read-only
31
30
29
28
27
26
25
24
19
18
17
16
PICNT
23
22
21
20
PICNT
15
14
CPIV
13
12
11
10
9
8
3
2
1
0
25
24
17
16
CPIV
7
6
5
4
CPIV
Reading this register clears PITS in PIT_SR.
• CPIV: Current Periodic Interval Value
Returns the current value of the periodic interval timer.
• PICNT: Periodic Interval Counter
Returns the number of occurrences of periodic intervals since the last read of PIT_PIVR.
16.4.4
Periodic Interval Timer Image Register
Register Name:
PIT_PIIR
Access Type:
Read-only
31
30
29
28
27
26
19
18
PICNT
23
22
21
20
PICNT
15
14
CPIV
13
12
11
10
9
8
3
2
1
0
CPIV
7
6
5
4
CPIV
• CPIV: Current Periodic Interval Value
Returns the current value of the periodic interval timer.
• PICNT: Periodic Interval Counter
Returns the number of occurrences of periodic intervals since the last read of PIT_PIVR.
128
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AT91SAM9263 Preliminary
17. Watchdog Timer (WDT)
17.1
Description
The Watchdog Timer can be used to prevent system lock-up if the software becomes trapped in
a deadlock. It features a 12-bit down counter that allows a watchdog period of up to 16 seconds
(slow clock at 32.768 kHz). It can generate a general reset or a processor reset only. In addition,
it can be stopped while the processor is in debug mode or idle mode.
17.2
Block Diagram
Figure 17-1. Watchdog Timer Block Diagram
write WDT_MR
WDT_MR
WDV
WDT_CR
WDRSTT
reload
1
0
12-bit Down
Counter
WDT_MR
WDD
reload
Current
Value
1/128
SLCK
<= WDD
WDT_MR
WDRSTEN
= 0
wdt_fault
(to Reset Controller)
set
set
read WDT_SR
or
reset
WDERR
reset
WDUNF
reset
wdt_int
WDFIEN
WDT_MR
129
6249B–ATARM–14-Dec-06
17.3
Functional Description
The Watchdog Timer can be used to prevent system lock-up if the software becomes trapped in
a deadlock. It is supplied with VDDCORE. It restarts with initial values on processor reset.
The Watchdog is built around a 12-bit down counter, which is loaded with the value defined in
the field WDV of the Mode Register (WDT_MR). The Watchdog Timer uses the Slow Clock
divided by 128 to establish the maximum Watchdog period to be 16 seconds (with a typical Slow
Clock of 32.768 kHz).
After a Processor Reset, the value of WDV is 0xFFF, corresponding to the maximum value of
the counter with the external reset generation enabled (field WDRSTEN at 1 after a Backup
Reset). This means that a default Watchdog is running at reset, i.e., at power-up. The user must
either disable it (by setting the WDDIS bit in WDT_MR) if he does not expect to use it or must
reprogram it to meet the maximum Watchdog period the application requires.
The Watchdog Mode Register (WDT_MR) can be written only once. Only a processor reset
resets it. Writing the WDT_MR register reloads the timer with the newly programmed mode
parameters.
In normal operation, the user reloads the Watchdog at regular intervals before the timer underflow occurs, by writing the Control Register (WDT_CR) with the bit WDRSTT to 1. The
Watchdog counter is then immediately reloaded from WDT_MR and restarted, and the Slow
Clock 128 divider is reset and restarted. The WDT_CR register is write-protected. As a result,
writing WDT_CR without the correct hard-coded key has no effect. If an underflow does occur,
the “wdt_fault” signal to the Reset Controller is asserted if the bit WDRSTEN is set in the Mode
Register (WDT_MR). Moreover, the bit WDUNF is set in the Watchdog Status Register
(WDT_SR).
To prevent a software deadlock that continuously triggers the Watchdog, the reload of the
Watchdog must occur while the Watchdog counter is within a window between 0 and WDD,
WDD is defined in the WatchDog Mode Register WDT_MR.
Any attempt to restart the Watchdog while the Watchdog counter is between WDV and WDD
results in a Watchdog error, even if the Watchdog is disabled. The bit WDERR is updated in the
WDT_SR and the “wdt_fault” signal to the Reset Controller is asserted.
Note that this feature can be disabled by programming a WDD value greater than or equal to the
WDV value. In such a configuration, restarting the Watchdog Timer is permitted in the whole
range [0; WDV] and does not generate an error. This is the default configuration on reset (the
WDD and WDV values are equal).
The status bits WDUNF (Watchdog Underflow) and WDERR (Watchdog Error) trigger an interrupt, provided the bit WDFIEN is set in the mode register. The signal “wdt_fault” to the reset
controller causes a Watchdog reset if the WDRSTEN bit is set as already explained in the reset
controller programmer Datasheet. In that case, the processor and the Watchdog Timer are
reset, and the WDERR and WDUNF flags are reset.
If a reset is generated or if WDT_SR is read, the status bits are reset, the interrupt is cleared,
and the “wdt_fault” signal to the reset controller is deasserted.
Writing the WDT_MR reloads and restarts the down counter.
While the processor is in debug state or in idle mode, the counter may be stopped depending on
the value programmed for the bits WDIDLEHLT and WDDBGHLT in the WDT_MR.
130
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Figure 17-2. Watchdog Behavior
Watchdog Error
Watchdog Underflow
if WDRSTEN is 1
FFF
Normal behavior
if WDRSTEN is 0
WDV
Forbidden
Window
WDD
Permitted
Window
0
Watchdog
Fault
131
WDT_CR = WDRSTT
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
17.4
Watchdog Timer (WDT) User Interface
Table 17-1.
Offset
132
Watchdog Timer Registers
Register
Name
Access
Reset Value
0x00
Control Register
WDT_CR
Write-only
-
0x04
Mode Register
WDT_MR
Read/Write Once
0x3FFF_2FFF
0x08
Status Register
WDT_SR
Read-only
0x0000_0000
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6249B–ATARM–14-Dec-06
17.4.1
Watchdog Timer Control Register
Register Name:
WDT_CR
Access Type:
31
Write-only
30
29
28
27
26
25
24
KEY
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
–
14
–
13
–
12
–
11
–
10
–
9
–
8
–
7
–
6
–
5
–
4
–
3
–
2
–
1
–
0
WDRSTT
• WDRSTT: Watchdog Restart
0: No effect.
1: Restarts the Watchdog.
• KEY: Password
Should be written at value 0xA5. Writing any other value in this field aborts the write operation.
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17.4.2
Watchdog Timer Mode Register
Register Name:
WDT_MR
Access Type:
31
Read/Write Once
30
23
29
WDIDLEHLT
28
WDDBGHLT
27
21
20
19
11
22
26
25
24
18
17
16
10
9
8
1
0
WDD
WDD
15
WDDIS
14
13
12
WDRPROC
WDRSTEN
WDFIEN
7
6
5
4
WDV
3
2
WDV
• WDV: Watchdog Counter Value
Defines the value loaded in the 12-bit Watchdog Counter.
• WDFIEN: Watchdog Fault Interrupt Enable
0: A Watchdog fault (underflow or error) has no effect on interrupt.
1: A Watchdog fault (underflow or error) asserts interrupt.
• WDRSTEN: Watchdog Reset Enable
0: A Watchdog fault (underflow or error) has no effect on the resets.
1: A Watchdog fault (underflow or error) triggers a Watchdog reset.
• WDRPROC: Watchdog Reset Processor
0: If WDRSTEN is 1, a Watchdog fault (underflow or error) activates all resets.
1: If WDRSTEN is 1, a Watchdog fault (underflow or error) activates the processor reset.
• WDD: Watchdog Delta Value
Defines the permitted range for reloading the Watchdog Timer.
If the Watchdog Timer value is less than or equal to WDD, writing WDT_CR with WDRSTT = 1 restarts the timer.
If the Watchdog Timer value is greater than WDD, writing WDT_CR with WDRSTT = 1 causes a Watchdog error.
• WDDBGHLT: Watchdog Debug Halt
0: The Watchdog runs when the processor is in debug state.
1: The Watchdog stops when the processor is in debug state.
• WDIDLEHLT: Watchdog Idle Halt
0: The Watchdog runs when the system is in idle mode.
1: The Watchdog stops when the system is in idle state.
• WDDIS: Watchdog Disable
0: Enables the Watchdog Timer.
1: Disables the Watchdog Timer.
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17.4.3
Watchdog Timer Status Register
Register Name:
WDT_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
WDERR
0
WDUNF
• WDUNF: Watchdog Underflow
0: No Watchdog underflow occurred since the last read of WDT_SR.
1: At least one Watchdog underflow occurred since the last read of WDT_SR.
• WDERR: Watchdog Error
0: No Watchdog error occurred since the last read of WDT_SR.
1: At least one Watchdog error occurred since the last read of WDT_SR.
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18. Shutdown Controller (SHDWC)
18.1
Description
The Shutdown Controller controls the power supplies VDDIO and VDDCORE and the wake-up
detection on debounced input lines.
18.2
Block Diagram
Figure 18-1. Shutdown Controller Block Diagram
SLCK
Shutdown Controller
read SYSC_SHSR
SYSC_SHMR
CPTWK0
reset
WAKEUP0 SYSC_SHSR
WKMODE0
set
WKUP0
read SYSC_SHSR
Wake-up
reset
RTTWKEN
SYSC_SHMR
RTT Alarm
RTTWK
Shutdown
Output
Controller
SYSC_SHSR
set
SHDN
SYSC_SHCR
SHDW
18.3
I/O Lines Description
Table 18-1.
18.4
18.4.1
18.5
Shutdown
I/O Lines Description
Name
Description
Type
WKUP0
Wake-up 0 input
Input
SHDN
Shutdown output
Output
Product Dependencies
Power Management
The Shutdown Controller is continuously clocked by Slow Clock. The Power Management Controller has no effect on the behavior of the Shutdown Controller.
Functional Description
The Shutdown Controller manages the main power supply. To do so, it is supplied with VDDBU
and manages wake-up input pins and one output pin, SHDN.
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6249B–ATARM–14-Dec-06
A typical application connects the pin SHDN to the shutdown input of the DC/DC Converter providing the main power supplies of the system, and especially VDDCORE and/or VDDIO. The
wake-up inputs (WKUP0) connect to any push-buttons or signal that wake up the system.
The software is able to control the pin SHDN by writing the Shutdown Control Register
(SHDW_CR) with the bit SHDW at 1. The shutdown is taken into account only 2 slow clock
cycles after the write of SHDW_CR. This register is password-protected and so the value written
should contain the correct key for the command to be taken into account. As a result, the system
should be powered down.
A level change on WKUP0 is used as wake-up. Wake-up is configured in the Shutdown Mode
Register (SHDW_MR). The transition detector can be programmed to detect either a positive or
negative transition or any level change on WKUP0. The detection can also be disabled. Programming is performed by defining WKMODE0.
Moreover, a debouncing circuit can be programmed for WKUP0. The debouncing circuit filters
pulses on WKUP0 shorter than the programmed number of 16 SLCK cycles in CPTWK0 of the
SHDW_MR register. If the programmed level change is detected on a pin, a counter starts.
When the counter reaches the value programmed in the corresponding field, CPTWK0, the
SHDN pin is released. If a new input change is detected before the counter reaches the corresponding value, the counter is stopped and cleared. WAKEUP0 of the Status Register
(SHDW_SR) reports the detection of the programmed events on WKUP0, with a reset after the
read of SHDW_SR.
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18.6
Shutdown Controller (SHDWC) User Interface
18.6.1
Register Mapping
Table 18-2.
Shutdown Controller (SHDWC) Registers
Offset
Register
Name
Access
Reset Value
0x00
Shutdown Control Register
SHDW_CR
Write-only
-
0x04
Shutdown Mode Register
SHDW_MR
Read-Write
0x0000_0103
0x18
Shutdown Status Register
SHDW_SR
Read-only
0x0000_0000
18.6.2
Shutdown Control Register
Register Name:
SHDW_CR
Access Type:
31
Write-only
30
29
28
27
26
25
24
KEY
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
–
14
–
13
–
12
–
11
–
10
–
9
–
8
–
7
–
6
–
5
–
4
–
3
–
2
–
1
–
0
SHDW
• SHDW: Shutdown Command
0 = No effect.
1 = If KEY is correct, asserts the SHDN pin.
• KEY: Password
Should be written at value 0xA5. Writing any other value in this field aborts the write operation.
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6249B–ATARM–14-Dec-06
18.6.3
Shutdown Mode Register
Register Name:
SHDW_MR
Access Type:
Read/Write
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
RTTWKEN
15
14
13
12
11
–
10
–
9
8
3
–
2
–
1
–
7
6
5
4
CPTWK0
–
0
WKMODE0
• WKMODE0: Wake-up Mode 0
WKMODE[1:0]
Wake-up Input Transition Selection
0
0
None. No detection is performed on the wake-up input
0
1
Low to high level
1
0
High to low level
1
1
Both levels change
• CPTWK0: Counter on Wake-up 0
Defines the number of 16 Slow Clock cycles, the level detection on the corresponding input pin shall last before the wakeup event occurs. Because of the internal synchronization of WKUP0 , the SHDN pin is released
(CPTWK x 16 + 1) Slow Clock cycles after the event on WKUP.
• RTTWKEN: Real-time Timer Wake-up Enable
0 = The RTT Alarm signal has no effect on the Shutdown Controller.
1 = The RTT Alarm signal forces the de-assertion of the SHDN pin.
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18.6.4
Shutdown Status Register
Register Name:
SHDW_SR
Access Type:
Read-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
RTTWK
15
–
14
–
13
–
12
–
11
–
10
–
9
–
8
–
7
–
6
–
5
–
4
–
3
–
2
–
1
–
0
WAKEUP0
• WAKEUP0: Wake-up 0 Status
0 = No wake-up event occurred on the corresponding wake-up input since the last read of SHDW_SR.
1 = At least one wake-up event occurred on the corresponding wake-up input since the last read of SHDW_SR.
• RTTWK: Real-time Timer Wake-up
0 = No wake-up alarm from the RTT occurred since the last read of SHDW_SR.
1 = At least one wake-up alarm from the RTT occurred since the last read of SHDW_SR.
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19. AT91SAM9263 Bus Matrix
19.1
Description
Bus Matrix implements a multi-layer AHB, based on AHB-Lite protocol, that enables parallel
access paths between multiple AHB masters and slaves in a system, which increases the
overall bandwidth. Bus Matrix interconnects 9 AHB Masters to 8 AHB Slaves. The normal
latency to connect a master to a slave is one cycle except for the default master of the
accessed slave which is connected directly (zero cycle latency).
The Bus Matrix user interface is compliant with ARM Advanced Peripheral Bus and provides a
Chip Configuration User Interface with Registers that allow the Bus Matrix to support application specific features.
19.2
Memory Mapping
Bus Matrix provides one decoder for every AHB Master Interface. The decoder offers each
AHB Master several memory mappings. In fact, depending on the product, each memory area
may be assigned to several slaves. Booting at the same address while using different AHB
slaves (i.e., external RAM, internal ROM or internal Flash, etc.) becomes possible.
The Bus Matrix user interface provides Master Remap Control Register (MATRIX_MRCR) that
allows to perform remap action for every master independently.
19.3
Special Bus Granting Techniques
The Bus Matrix provides some speculative bus granting techniques in order to anticipate
access requests from some masters. This mechanism allows to reduce latency at first
accesses of a burst or single transfer. The bus granting mechanism allows to set a default
master for every slave.
At the end of the current access, if no other request is pending, the slave remains connected
to its associated default master. A slave can be associated with three kinds of default masters:
no default master, last access master and fixed default master.
19.3.1
No Default Master
At the end of the current access, if no other request is pending, the slave is disconnected from
all masters. No Default Master, suits low power mode.
19.3.2
Last Access Master
At the end of the current access, if no other request is pending, the slave remains connected
to the last master that performed an access request.
19.3.3
Fixed Default Master
At the end of the current access, if no other request is pending, the slave connects to itsfixed
default master. Unlike last access master, the fixed master doesn’t change unless the user
modifies it by a software action (field FIXED_DEFMSTR of the related MATRIX_SCFG).
To change from one kind of default master to another, the Bus Matrix user interface provides
the Slave Configuration Registers, one for each slave, that allow to set a default master for
each slave. The Slave Configuration Register contains two fields:
DEFMSTR_TYPE and FIXED_DEFMSTR. The 2-bit DEFMSTR_TYPE field allows to choose
the default master type (no default, last access master, fixed default master) whereas the 4-bit
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6249B–ATARM–14-Dec-06
FIXED_DEFMSTR field allows to choose a fixed default master provided that
DEFMSTR_TYPE is set to fixed default master. Please refer to the Bus Matrix user interface
description.
19.4
Arbitration
The Bus Matrix provides an arbitration mechanism that allows to reduce latency when conflict
cases occur, basically when two or more masters try to access the same slave at the same
time. One arbiter per AHB slave is provided, allowing to arbitrate each slave differently.
The Bus Matrix provides to the user the possibility to choose between 2 arbitration types, and
this for each slave:
1. Round-Robin Arbitration (the default)
2. Fixed Priority Arbitration
This choice is given through the field ARBT of the Slave Configuration Registers
(MATRIX_SCFG).
Each algorithm may be complemented by selecting a default master configuration for each
slave.
When a re-arbitration has to be done, it is realized only under some specific conditions
detailed in the following paragraph.
19.4.1
Arbitration rules
Each arbiter has the ability to arbitrate between two or more different master’s requests. In
order to avoid burst breaking and also to provide the maximum throughput for slave interfaces,
arbitration may only take place during the following cycles:
1. Idle Cycles: when a slave is not connected to any master or is connected to a master
which is not currently accessing it.
2. Single Cycles: when a slave is currently doing a single access.
3. End of Burst Cycles: when the current cycle is the last cycle of a burst transfer. For
defined length burst, predicted end of burst matches the size of the transfer but is
managed differently for undefined length burst (See “Undefined Length Burst Arbitration” on page iv.).
4. Slot Cycle Limit: when the slot cycle counter has reach the limit value indicating that
the current master access is too long and must be broken (See “Slot Cycle Limit Arbitration” on page iv.).
19.4.1.1
Undefined Length Burst Arbitration
In order to avoid too long slave handling during undefined length bursts (INCR), the Bus Matrix
provides specific logic in order to re-arbitrate before the end of the INCR transfer.
A predicted end of burst is used as for defined length burst transfer, which is selected between
the following:
1. Infinite: no predicted end of burst is generated and therefore INCR burst transfer will
never be broken.
2. Four beat bursts: predicted end of burst is generated at the end of each four beat
boundary inside INCR transfer.
3. Eight beat bursts: predicted end of burst is generated at the end of each eight beat
boundary inside INCR transfer.
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4. Sixteen beat bursts: predicted end of burst is generated at the end of each sixteen
beat boundary inside INCR transfer.
This selection can be done through the field ULBT of the Master Configuration Registers
(MATRIX_MCFG).
19.4.1.2
19.4.2
Slot Cycle Limit Arbitration
The Bus Matrix contains specific logic to break too long accesses such as very long bursts on
a very slow slave (e.g. an external low speed memory). At the beginning of the burst access, a
counter is loaded with the value previously written in the SLOT_CYCLE field of the related
Slave Configuration Register (MATRIX_SCFG) and decreased at each clock cycle. When the
counter reaches zero, the arbiter has the ability to re-arbitrate at the end of the current byte,
half word or word transfer.
Round-Robin Arbitration
This algorithm allows the Bus Matrix arbiters to dispatch the requests from different masters to
the same slave in a round-robin manner. If two or more master’s requests arise at the same
time, the master with the lowest number is first serviced then the others are serviced in a
round-robin manner.
There are three round-robin algorithm implemented:
• Round-Robin arbitration without default master
• Round-Robin arbitration with last access master
• Round-Robin arbitration with fixed default master
19.4.2.1
Round-Robin Arbitration without Default Master
This is the main algorithm used by Bus Matrix arbiters. It allows the Bus Matrix to dispatch
requests from different masters to the same slave in a pure round-robin manner. At the end of
the current access, if no other request is pending, the slave is disconnected from all masters.
This configuration incurs one latency cycle for the first access of a burst. Arbitration without
default master can be used for masters that perform significant bursts.
19.4.2.2
Round-Robin Arbitration with Last Access Master
This is a biased round-robin algorithm used by Bus Matrix arbiters. It allows the Bus Matrix to
remove the one latency cycle for the last master that accessed the slave. In fact, at the end of
the current transfer, if no other master request is pending, the slave remains connected to the
last master that performs the access. Other non privileged masters will still get one latency
cycle if they want to access the same slave. This technique can be used for masters that
mainly perform single accesses.
19.4.2.3
Round-Robin Arbitration with Fixed Default Master
This is another biased round-robin algorithm, it allows the Bus Matrix arbiters to remove the
one latency cycle for the fixed default master per slave. At the end of the current access, the
slave remains connected to its fixed default master. Every request attempted by this fixed
default master will not cause any latency whereas other non privileged masters will still get
one latency cycle. This technique can be used for masters that mainly perform single
accesses.
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6249B–ATARM–14-Dec-06
19.4.3
Fixed Priority Arbitration
This algorithm allows the Bus Matrix arbiters to dispatch the requests from different masters to
the same slave by using the fixed priority defined by the user. If two or more master’s requests
are active at the same time, the master with the highest priority number is serviced first. If two
or more master’s requests with the same priority are active at the same time, the master with
the highest number is serviced first.
For each slave, the priority of each master may be defined through the Priority Registers for
Slaves (MATRIX_PRAS and MATRIX_PRBS).
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19.5
Bus Matrix User Interface
Table 19-1.
Register Mapping
Offset
Register
Name
Access
Reset Value
0x0000
Master Configuration Register 0
MATRIX_MCFG0
Read/Write
0x00000000
0x0004
Master Configuration Register 1
MATRIX_MCFG1
Read/Write
0x00000000
0x0008
Master Configuration Register 2
MATRIX_MCFG2
Read/Write
0x00000000
0x000C
Master Configuration Register 3
MATRIX_MCFG3
Read/Write
0x00000000
0x0010
Master Configuration Register 4
MATRIX_MCFG4
Read/Write
0x00000000
0x0014
Master Configuration Register 5
MATRIX_MCFG5
Read/Write
0x00000000
0x0018
Master Configuration Register 6
MATRIX_MCFG6
Read/Write
0x00000000
0x001C
Master Configuration Register 7
MATRIX_MCFG7
Read/Write
0x00000000
0x0020
Master Configuration Register 8
MATRIX_MCFG8
Read/Write
0x00000000
–
–
0x0024 - 0x003C
Reserved
–
0x0040
Slave Configuration Register 0
MATRIX_SCFG0
Read/Write
0x00010010
0x0044
Slave Configuration Register 1
MATRIX_SCFG1
Read/Write
0x00050010
0x0048
Slave Configuration Register 2
MATRIX_SCFG2
Read/Write
0x00000010
0x004C
Slave Configuration Register 3
MATRIX_SCFG3
Read/Write
0x00000010
0x0050
Slave Configuration Register 4
MATRIX_SCFG4
Read/Write
0x00000010
0x0054
Slave Configuration Register 5
MATRIX_SCFG5
Read/Write
0x00000010
0x0058
Slave Configuration Register 6
MATRIX_SCFG6
Read/Write
0x00000010
0x005C
Slave Configuration Register 7
MATRIX_SCFG7
Read/Write
0x00000010
–
–
0x0060 - 0x007C
Reserved
–
0x0080
Priority Register A for Slave 0
MATRIX_PRAS0
Read/Write
0x00000000
0x0084
Priority Register B for Slave 0
MATRIX_PRBS0
Read/Write
0x00000000
0x0088
Priority Register A for Slave 1
MATRIX_PRAS1
Read/Write
0x00000000
0x008C
Priority Register B for Slave 1
MATRIX_PRBS1
Read/Write
0x00000000
0x0090
Priority Register A for Slave 2
MATRIX_PRAS2
Read/Write
0x00000000
0x0094
Priority Register B for Slave 2
MATRIX_PRBS2
Read/Write
0x00000000
0x0098
Priority Register A for Slave 3
MATRIX_PRAS3
Read/Write
0x00000000
0x009C
Priority Register B for Slave 3
MATRIX_PRBS3
Read/Write
0x00000000
0x00A0
Priority Register A for Slave 4
MATRIX_PRAS4
Read/Write
0x00000000
0x00A4
Priority Register B for Slave 4
MATRIX_PRBS4
Read/Write
0x00000000
0x00A8
Priority Register A for Slave 5
MATRIX_PRAS5
Read/Write
0x00000000
0x00AC
Priority Register B for Slave 5
MATRIX_PRBS5
Read/Write
0x00000000
0x00B0
Priority Register A for Slave 6
MATRIX_PRAS6
Read/Write
0x00000000
0x00B4
Priority Register B for Slave 6
MATRIX_PRBS6
Read/Write
0x00000000
0x00B8
Priority Register A for Slave 7
MATRIX_PRAS7
Read/Write
0x00000000
0x00BC
Priority Register B for Slave 7
MATRIX_PRBS7
Read/Write
0x00000000
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AT91SAM9263 Preliminary
Table 19-1.
Register Mapping
Offset
Register
0x00C0 - 0x00FC
Reserved
0x0100
0x0104 - 0x010C
Master Remap Control Register
Reserved
Name
–
MATRIX_MRCR
–
Access
Reset Value
–
–
Read/Write
0x00000000
–
–
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19.5.1
Bus Matrix Master Configuration Registers
Register Name:
MATRIX_MCFG0...MATRIX_MCFG8
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
–
–
–
–
–
ULBT
• ULBT: Undefined Length Burst Type
0: Infinite Length Burst
No predicted end of burst is generated and therefore INCR bursts coming from this master cannot be broken.
1: Single Access
The undefined length burst is treated as a succession of single accesses, allowing rearbitration at each beat of the INCR
burst.
2: Four-beat Burst
The undefined length burst is split into four-beat burst allowing rearbitration at each four-beat burst end.
3: Eight-beat Burst
The undefined length burst is split into eight-beat burst allowing rearbitration at each eight-beat burst end.
4: Sixteen-beat Burst
The undefined length burst is split into sixteen-beat burst allowing rearbitration at each sixteen-beat burst end.
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19.5.2
Bus Matrix Slave Configuration Registers
Register Name:
MATRIX_SCFG0...MATRIX_SCFG7
Access Type:
Read/Write
31
30
29
28
27
26
–
–
–
–
–
–
23
22
21
20
19
18
–
25
24
ARBT
17
FIXED_DEFMSTR
16
DEFMSTR_TYPE
15
14
13
12
11
10
9
8
–
–
–
–
–
–
–
–
7
6
5
4
3
2
1
0
SLOT_CYCLE
• SLOT_CYCLE: Maximum Number of Allowed Cycles for a Burst
When the SLOT_CYCLE limit is reached for a burst, it may be broken by another master trying to access this slave.
This limit has been placed to avoid locking a very slow slave when very long bursts are used.
Note that an unreasonably small value breaks every burst and the Bus Matrix then arbitrates without performing any data
transfer. 16 cycles is a reasonable value for SLOT_CYCLE.
• DEFMASTR_TYPE: Default Master Type
0: No Default Master
At the end of current slave access, if no other master request is pending, the slave is disconnected from all masters.
This results in a one-cycle latency for the first acccess of a burst transfer or for a single access.
1: Last Default Master
At the end of current slave access, if no other master request is pending, the slave remains connected to the last master
that accessed it.
This results in not having the one cycle latency when the last master tries access to the slave again.
2: Fixed Default Master
At the end of the current slave access, if no other master request is pending, the slave connects to the fixed master the
number of which has been written in the FIXED_DEFMSTR field.
This results in not having the one cycle latency when the fixed master tries access to the slave again.
• FIXED_DEFMSTR: Fixed Default Master
This is the number of the Default Master for this slave. Only used if DEFMASTR_TYPE is 2. Specifying the number of a
master which is not connected to the selected slave is equivalent to setting DEFMASTR_TYPE to 0.
• ARBT: Arbitration Type
0: Round-Robin Arbitration
1: Fixed Priority Arbitration
2: Reserved
3: Reserved
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AT91SAM9263 Preliminary
19.5.3
Bus Matrix Priority Registers A For Slaves
Register Name:
MATRIX_PRAS0...MATRIX_PRAS7
Access Type:
Read/Write
31
30
–
–
23
22
–
–
15
14
–
–
7
6
–
–
29
28
M7PR
21
20
M5PR
13
12
M3PR
5
4
M1PR
27
26
–
–
19
18
–
–
11
10
–
–
3
2
–
–
25
24
M6PR
17
16
M4PR
9
8
M2PR
1
0
M0PR
• MxPR: Master x Priority
Fixed prority of Master x for accessing to the selected slave.The higher the number, the higher the priority.
19.5.4
Bus Matrix Priority Registers B For Slaves
Register Name:
MATRIX_PRBS0...MATRIX_PRBS7
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
M8PR
• M8PR: Master 8 Priority
Fixed prority of Master 8 for accessing to the selected slave. The higher the number, the higher the priority.
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AT91SAM9263 Preliminary
19.5.5
Bus Matrix Master Remap Control Register
Register Name:
MATRIX_MRCR
Access Type:
Read/Write
Reset:
0x0000_0000
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
–
–
–
–
RCB8
7
6
5
4
3
2
1
0
RCB7
RCB6
RCB5
RCB4
RCB3
RCB2
RCB1
RCB0
• RCBx: Remap Command Bit for AHB Master x
0: Disable remapped address decoding for the selected Master.
1: Enable remapped address decoding for the selected Master.
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AT91SAM9263 Preliminary
19.6
Chip Configuration User Interface
Table 19-2.
Chip Configuration User Interface
Offset
Register
0x0110
Reserved
0x0114
Bus Matrix TCM Configuration Register
0x0118 - 0x011C
Name
–
MATRIX_TCMR
Reserved
–
Access
Reset Value
–
–
Read/Write
0x00000000
–
–
0x0120
EBI0 Chip Select Assignment Register
EBI0_CSA
Read/Write
0x00010000
0x0124
EBI1 Chip Select Assignment Register
EBI1_CSA
Read/Write
0x00010000
–
–
0x0128 - 0x01FC
19.6.1
Reserved
–
Bus Matrix TCM Configuration Register
Register Name:
MATRIX_TCR
Access Type:
Read/Write
Reset:
0x0000_0000
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
DTCM_SIZE
ITCM_SIZE
• ITCM_SIZE: Size of ITCM enabled memory block
0000: 0 KB (No ITCM Memory)
0101: 16 KB
0110: 32 KB
Others: Reserved
• DTCM_SIZE: Size of DTCM enabled memory block
0000: 0 KB (No DTCM Memory)
0101: 16 KB
0110: 32 KB
Others: Reserved
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19.6.2
EBI0 Chip Select Assignment Register
Register Name:
EBI0_CSA
Access Type:
Read/Write
Reset:
0x0001_0000
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
VDDIOMSEL
15
14
13
12
11
10
9
8
–
–
–
–
–
–
–
EBI0_DBPUC
7
6
5
4
3
2
1
0
–
–
EBI0_CS5A
EBI0_CS4A
EBI0_CS3A
–
EBI0_CS1A
–
• EBI0_CS1A: EBI0 Chip Select 1 Assignment
0 = EBI0 Chip Select 1 is assigned to the Static Memory Controller.
1 = EBI0 Chip Select 1 is assigned to the SDRAM Controller.
• EBI0_CS3A: EBI0 Chip Select 3 Assignment
0 = EBI0 Chip Select 3 is only assigned to the Static Memory Controller and EBI0_NCS3 behaves as defined by the SMC.
1 = EBI0 Chip Select 3 is assigned to the Static Memory Controller and the SmartMedia Logic is activated.
• EBI0_CS4A: EBI0 Chip Select 4 Assignment
0 = EBI0 Chip Select 4 is only assigned to the Static Memory Controller and EBI0_NCS4 behaves as defined by the SMC.
1 = EBI0 Chip Select 4 is assigned to the Static Memory Controller and the CompactFlash Logic (first slot) is activated.
• EBI0_CS5A: EBI0 Chip Select 5 Assignment
0 = EBI0 Chip Select 5 is only assigned to the Static Memory Controller and EBI0_NCS5 behaves as defined by the SMC.
1 = EBI0 Chip Select 5 is assigned to the Static Memory Controller and the CompactFlash Logic (second slot) is activated.
• EBI0_DBPUC: EBI0 Data Bus Pull-Up Configuration
0 = EBI0 D0 - D15 Data Bus bits are internally pulled-up to the VDDIOM0 power supply.
1 = EBI0 D0 - D15 Data Bus bits are not internally pulled-up.
• VDDIOMSEL: Memory voltage selection
0 = Memories are 1.8V powered.
1 = Memories are 3.3V powered.
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19.6.3
EBI1 Chip Select Assignment Register
Register Name:
EBI1_CSA
Access Type:
Read/Write
Reset:
0x0001_0000
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
VDDIOMSEL
15
14
13
12
11
10
9
8
–
–
–
–
–
–
–
EBI1_DBPUC
7
6
5
4
3
2
1
0
–
–
–
–
EBI1_CS2A
–
EBI1_CS1A
–
• EBI1_CS1A: EBI1 Chip Select 1 Assignment
0 = EBI1 Chip Select 1 is assigned to the Static Memory Controller.
1 = EBI1 Chip Select 1 is assigned to the SDRAM Controller.
• EBI1_CS2A: EBI1 Chip Select 2 Assignment
0 = EBI1 Chip Select 2 is only assigned to the Static Memory Controller and EBI1_NCS2 behaves as defined by the SMC.
1 = EBI1 Chip Select 2 is assigned to the Static Memory Controller and the SmartMedia Logic is activated.
• EBI1_DBPUC: EBI1 Data Bus Pull-Up Configuration
0 = EBI1 D0 - D15 Data Bus bits are internally pulled-up to the VDDIOM1 power supply.
1 = EBI1 D0 - D15 Data Bus bits are not internally pulled-up.
• VDDIOMSEL: Memory voltage selection
0 = Memories are 1.8V powered.
1 = Memories are 3.3V powered.
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
20. External Bus Interface (EBI)
20.1
Description
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 ECC Controllers are all featured external Memory Controllers on
the EBI. These external Memory Controllers are capable of handling several types of external
memory and peripheral devices, such as SRAM, PROM, EPROM, EEPROM, Flash, and
SDRAM.
The EBI0 also supports the CompactFlash and the NANDFlash protocols via integrated circuitry that greatly reduces the requirements for external components. Furthermore, the EBI0
handles data transfers with up to six external devices, each assigned to six address spaces
defined by the embedded Memory Controller. Data transfers are performed through a 16-bit or
32-bit data bus, an address bus of up to 26 bits, up to six chip select lines (NCS[5:0]) and several control pins that are generally multiplexed between the different external Memory
Controllers.
The EBI1 also supports the NANDFlash protocols via integrated circuitry that greatly reduces
the requirements for external components. Furthermore, the EBI1 handles data transfers with
up to three external devices, each assigned to three 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 23 bits, up to three chip select lines (NCS[2:0]) and several control pins
that are generally multiplexed between the different external Memory Controllers.
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6249B–ATARM–14-Dec-06
20.2
20.2.1
Block Diagram
External Bus Interface 0
Figure 20-1 shows the organization of the External Bus Interface 0.
Figure 20-1. Organization of the External Bus Interface 0
External Bus Interface 0
Bus Matrix
D[15:0]
AHB
SDRAM
Controller
A0/NBS0
A1/NWR2/NBS2
A[15:2], A[22:18]
A16/BA0
MUX
Logic
Static
Memory
Controller
A17/BA1
NCS0
NCS1/SDCS
NCS3/NANDCS
NRD/CFOE
NWR0/NWE/CFWE
NWR1/NBS1/CFIOR
NWR3/NBS3/CFIOW
CompactFlash
Logic
SDCK
SDCKE
RAS
CAS
NAND Flash
Logic
SDWE
SDA10
NANDOE
NANDWE
ECC
Controller
D[31:16]
PIO
Address Decoders
Chip Select
Assignor
A[25:23]
CFRNW
NCS4/CFCS0
NCS5/CFCS1
NCS2
User Interface
NWAIT
CFCE1
CFCE2
APB
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
20.2.2
External Bus Interface 1
Figure 20-2 shows the organization of the External Bus Interface 1.
Figure 20-2. Organization of the External Bus Interface 1
External Bus Interface 1
Bus Matrix
AHB
SDRAM
Controller
D[15:0]
A0/NBS0
MUX
Logic
Static
Memory
Controller
A1/NWR2/NBS2
A[15:2], A[22:18]
A16/BA0
A17/BA1
NCS0
NRD
NWR0/NWE
NWR1/NBS1
NAND Flash
Logic
SDWE
SDA10
ECC
Controller
NANDOE
NANDWE
D[31:16]
PIO
Address Decoders
Chip Select
Assignor
NWR3/NBS3
NCS1/SDCS
NCS2/NANDCS
SDCK
SDCKE
User Interface
NWAIT
RAS
CAS
APB
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AT91SAM9263 Preliminary
20.3
I/O Lines Description
Table 20-1.
EBI0 I/O Lines Description
Name
Function
Type
Active Level
EBI
EBI0_D0 - EBI0_D31
Data Bus
I/O
EBI0_A0 - EBI0_A25
Address Bus
EBI0_NWAIT
External Wait Signal
Output
Input
Low
SMC
EBI0_NCS0 - EBI0_NCS5
Chip Select Lines
Output
Low
EBI0_NWR0 - EBI0_NWR3
Write Signals
Output
Low
EBI0_NRD
Read Signal
Output
Low
EBI0_NWE
Write Enable
Output
Low
EBI0_NBS0 - EBI0_NBS3
Byte Mask Signals
Output
Low
EBI for CompactFlash Support
EBI0_CFCE1 - EBI0_CFCE2
CompactFlash Chip Enable
Output
Low
EBI0_CFOE
CompactFlash Output Enable
Output
Low
EBI0_CFWE
CompactFlash Write Enable
Output
Low
EBI0_CFIOR
CompactFlash I/O Read Signal
Output
Low
EBI0_CFIOW
CompactFlash I/O Write Signal
Output
Low
EBI0_CFRNW
CompactFlash Read Not Write Signal
Output
EBI0_CFCS0 - EBI0_CFCS1
CompactFlash Chip Select Lines
Output
Low
EBI for NAND Flash Support
EBI0_NANDCS
NAND Flash Chip Select Line
Output
Low
EBI0_NANDOE
NAND Flash Output Enable
Output
Low
EBI0_NANDWE
NAND Flash Write Enable
Output
Low
SDRAM Controller
EBI0_SDCK
SDRAM Clock
Output
EBI0_SDCKE
SDRAM Clock Enable
Output
High
EBI0_SDCS
SDRAM Controller Chip Select Line
Output
Low
EBI0_BA0 - EBI0_BA1
Bank Select
Output
EBI0_SDWE
SDRAM Write Enable
Output
Low
EBI0_RAS - EBI0_CAS
Row and Column Signal
Output
Low
EBI0_NWR0 - EBI0_NWR3
Write Signals
Output
Low
EBI0_NBS0 - EBI0_NBS3
Byte Mask Signals
Output
Low
EBI0_SDA10
SDRAM Address 10 Line
Output
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AT91SAM9263 Preliminary
Table 20-2.
EBI1 I/O Lines Description
Name
Function
Type
Active Level
EBI
EBI1_D0 - EBI1_D31
Data Bus
I/O
EBI1_A0 - EBI1_A23
Address Bus
EBI1_NWAIT
External Wait Signal
Output
Input
Low
SMC
EBI1_NCS0 - EBI1_NCS2
Chip Select Lines
Output
Low
EBI1_NWR0 - EBI1_NWR3
Write Signals
Output
Low
EBI1_NRD
Read Signal
Output
Low
EBI1_NWE
Write Enable
Output
Low
EBI1_NBS0 - EBI1_NBS3
Byte Mask Signals
Output
Low
EBI for NAND Flash Support
EBI1_NANDCS
NAND Flash Chip Select Line
Output
Low
EBI1_NANDOE
NAND Flash Output Enable
Output
Low
EBI1_NANDWE
NAND Flash Write Enable
Output
Low
SDRAM Controller
EBI1_SDCK
SDRAM Clock
Output
EBI1_SDCKE
SDRAM Clock Enable
Output
High
EBI1_SDCS
SDRAM Controller Chip Select Line
Output
Low
EBI1_BA0 - EBI1_BA1
Bank Select
Output
EBI1_SDWE
SDRAM Write Enable
Output
Low
EBI1_RAS - EBI1_CAS
Row and Column Signal
Output
Low
EBI1_NWR0 - EBI1_NWR3
Write Signals
Output
Low
EBI1_NBS0 - EBI1_NBS3
Byte Mask Signals
Output
Low
EBI1_SDA10
SDRAM Address 10 Line
Output
The connection of some signals through the MUX logic is not direct and depends on the Memory Controller in use at the moment.
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Table 20-3 on page 162 details the connections between the two Memory Controllers and the
EBI pins.
EBIx Pins and Memory Controllers I/O Lines Connections(1)
Table 20-3.
EBIx Pins(1)
SDRAMC I/O Lines
SMC I/O Lines
EBIx_NWR1/NBS1/CFIOR
NBS1
NWR1/NUB
EBIx_A0/NBS0
Not Supported
SMC_A0/NLB
EBIx_A1/NBS2/NWR2
Not Supported
SMC_A1
EBIx_A[11:2]
SDRAMC_A[9:0]
SMC_A[11:2]
EBIx_SDA10
SDRAMC_A10
Not Supported
EBIx_A12
Not Supported
SMC_A12
EBIx_A[14:13]
SDRAMC_A[12:11]
SMC_A[14:13]
EBIx_A[22:15]
Not Supported
SMC_A[22:15]
EBIx_A[25:23](2)
Not Supported
SMC_A[25:23]
EBIx_D[31:0]
D[31:0]
D[31:0]
Note:
1. x indicates 0 or 1
2. Only for EBI0
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AT91SAM9263 Preliminary
20.4
Application Example
20.4.1
Hardware Interface
Table 20-4 on page 163 details the connections to be applied between the EBI pins and the
external devices for each Memory Controller.
Table 20-4.
EBI Pins and External Static Devices Connections
Pins of the Interfaced Device
8-bit Static
Device
Signals:
EBI0_, EBI1_
2 x 8-bit
Static
Devices
16-bit Static
Device
Controller
4 x 8-bit
Static
Devices
2 x 16-bit
Static
Devices
32-bit Static
Device
SMC
D0 - D7
D0 - D7
D0 - D7
D0 - D7
D0 - D7
D0 - D7
D0 - D7
D8 - D15
–
D8 - D15
D8 - D15
D8 - D15
D8 - 15
D8 - 15
D16 - D23
–
–
–
D16 - D23
D16 - D23
D16 - D23
D24 - D31
–
–
–
D24 - D31
D24 - D31
D24 - D31
BE0(6)
A0/NBS0
A0
–
NLB
–
A1/NWR2/NBS2
A1
A0
A0
WE(2)
NLB(4)
BE2(6)
A[2:22]
A[1:21]
A[1:21]
A[0:20]
A[0:20]
A[0:20]
A[23:25]
A[22:24]
A[22:24]
A[21:23]
A[21:23]
A[21:23]
NCS0
CS
CS
CS
CS
CS
CS
NCS1/SDCS
CS
CS
CS
CS
CS
CS
CS
CS
CS
CS
CS
CS
A2 - A22
A23 - A25
(5)
NCS2
NCS3/NANDCS
(5)
NLB
(3)
CS
CS
CS
CS
CS
CS
NCS4/CFCS0
(5)
CS
CS
CS
CS
CS
CS
NCS5/CFCS1
(5)
CS
CS
CS
CS
CS
CS
OE
OE
OE
OE
OE
OE
WE
WE
NRD/CFOE
NWR0/NWE
WE
WE
(1)
(1)
NWR1/NBS1
–
WE
NWR3/NBS3
–
–
Notes:
1.
2.
3.
4.
5.
6.
WE
NUB
–
WE
(2)
WE
(2)
WE(2)
(3)
BE1(6)
NUB(4)
BE3(6)
NUB
NWR1 enables upper byte writes. NWR0 enables lower byte writes.
NWRx enables corresponding byte x writes. (x = 0,1,2 or 3)
NBS0 and NBS1 enable respectively lower and upper bytes of the lower 16-bit word.
NBS2 and NBS3 enable respectively lower and upper bytes of the upper 16-bit word.
EBI0 signals only
BEx: Byte x Enable (x = 0,1,2 or 3)
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Table 20-5.
EBI Pins and External Devices Connections
Pins of the Interfaced Device
Signals:
EBI0_, EBI1_
SDRAM
Controller
CompactFlash
(EBI0 only)
SDRAMC
CompactFlash
True IDE Mode
(EBI0 only)
NAND Flash
SMC
D0 - D7
D0 - D7
D0 - D7
D0 - D7
AD0-AD7
D8 - D15
D8 - D15
D8 - 15
D8 - 15
AD8-AD15
D16 - D31
D16 - D31
–
–
–
A0/NBS0
DQM0
A0
A0
–
A1/NWR2/NBS2
DQM2
A1
A1
–
A2 - A10
A[0:8]
A[2:10]
A[2:10]
–
A11
A9
–
–
–
SDA10
A10
–
–
–
–
–
–
–
A[11:12]
–
–
–
–
–
–
–
A16/BA0
BA0
–
–
–
A17/BA1
BA1
–
–
–
A18 - A20
–
–
–
–
A21
–
–
–
ALE(3)
A22
–
REG
REG
CLE(3)
–
–
A12
A13 - A14
A15
A23 - A24(4)
–
–
NCS0
–
–
–
–
CS
–
–
–
A25
NCS1/SDCS
NCS2
(4)
CFRNW
(1)
–
(4)
CFRNW
(1)
–
–
–
–
–
NCS2/NANDCS
(5)
–
–
–
–
NCS3/NANDCS
(4)
–
–
NCS4/CFCS0
(4)
NCS5/CFCS1
(4)
–
–
–
CFCS0
(1)
CFCS1
(1)
–
CFCS0
(1)
–
CFCS1
(1)
–
(4)
–
–
–
OE
(4)
–
–
–
WE
NRD/CFOE
–
OE
–
–
NWR0/NWE/CFWE
–
WE
WE
–
NWR1/NBS1/CFIOR
DQM1
IOR
IOR
–
NWR3/NBS3/CFIOW
NANDOE
NANDWE
DQM3
IOW
IOW
–
CFCE1
(4)
–
CE1
CS0
–
CFCE2
(4)
–
CE2
CS1
–
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Table 20-5.
EBI Pins and External Devices Connections (Continued)
Pins of the Interfaced Device
Signals:
EBI0_, EBI1_
Controller
SDRAM
CompactFlash
(EBI0 only)
SDRAMC
CompactFlash
True IDE Mode
(EBI0 only)
NAND Flash
SMC
SDCK
CLK
–
–
–
SDCKE
CKE
–
–
–
RAS
RAS
–
–
–
CAS
CAS
–
–
–
SDWE
WE
–
–
–
NWAIT
–
WAIT
WAIT
–
Pxx
(2)
–
CD1 or CD2
CD1 or CD2
–
Pxx
(2)
–
–
–
CE
Pxx
(2)
–
–
–
RDY
Note:
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 CLE and ALE signals of the NAND Flash device may be driven by any address bit. For details, see ”NAND Flash Support” on page 172.
4. EBI0 signals only
5. EBI1 signals only
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
20.4.2
Connection Examples
Figure 20-3 shows an example of connections between the EBI and external devices.
Figure 20-3. 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
D16-D23
NCS0
NCS1/SDCS
NCS2
NCS3
NCS4
NCS5
D0-D7
CS
CLK
CKE
SDWE WE
RAS
CAS
DQM
2M x 8
SDRAM
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
128K x 8
SRAM
D0-D7
D0-D7
A0-A16
128K x 8
SRAM
A1-A17
CS
OE
NRD/NOE
WE
A0/NWR0/NBS0
20.5
20.5.1
D8-D15
D0-D7
A0-A16
A1-A17
CS
OE
NRD/NOE
WE
NWR1/NBS1
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.
20.6
Functional Description
The EBI transfers data between the internal AHB Bus (handled by the Bus Matrix) and the
external memories or peripheral devices. It controls the waveforms and the parameters of the
external address, data and control buses and is composed of the following elements:
• the Static Memory Controller (SMC)
• the SDRAM Controller (SDRAMC)
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AT91SAM9263 Preliminary
• the ECC Controller (ECC)
• a chip select assignment feature that assigns an AHB address space to the external
devices
• a multiplex controller circuit that shares the pins between the different Memory Controllers
• programmable CompactFlash support logic (EBI0 only)
• programmable NAND Flash support logic
20.6.1
Bus Multiplexing
The EBI0 and EBI1 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.
20.6.2
Pull-up Control
The EBI0_CSA and EBI1_CSA registers in the Chip Configuration User Interface permit
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 EBIx_DBPUC bit
disables the pull-up resistors on the D0 to D15 lines. Enabling the pull-up resistor on the D16D31 lines can be performed by programming the appropriate PIO controller.
20.6.3
Static Memory Controller
For information on the Static Memory Controller, refer to the Static Memory Controller section.
20.6.4
SDRAM Controller
For information on the SDRAM Controller, refer to the SDRAM section.
20.6.5
ECC Controller
For information on the ECC Controller, refer to the ECC section.
20.6.6
CompactFlash Support (EBI0 only)
The External Bus Interface 0 integrates circuitry that interfaces to CompactFlash devices.
The CompactFlash logic is driven by the Static Memory Controller (SMC) on the NCS4 and/or
NCS5 address space. Programming the EBI0_CS4A and/or EBI0_CS5A bit of the EBI0_CSA
Register in the Chip Configuration User Interface to the appropriate value enables this logic.
For details on this register, refer to the in the Bus Matrix Section. Access to an external CompactFlash device is then made by accessing the address space reserved to NCS4 and/or
NCS5 (i.e., between 0x5000 0000 and 0x5FFF FFFF for NCS4 and between 0x6000 0000 and
0x6FFF FFFF for NCS5).
All CompactFlash modes (Attribute Memory, Common Memory, I/O and True IDE) are supported but the signals _IOIS16 (I/O and True IDE modes) and _ATA SEL (True IDE mode) are
not handled.
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20.6.6.1
I/O Mode, Common Memory Mode, Attribute Memory Mode and True IDE Mode
Within the NCS4 and/or NCS5 address space, the current transfer address is used to distinguish I/O mode, common memory mode, attribute memory mode and True IDE mode.
The different modes are accessed through a specific memory mapping as illustrated on Figure
20-4. A[23:21] bits of the transfer address are used to select the desired mode as described in
Table 20-6 on page 168.
Figure 20-4. CompactFlash Memory Mapping
True IDE Alternate Mode Space
Offset 0x00E0 0000
True IDE Mode Space
Offset 0x00C0 0000
CF Address Space
I/O Mode Space
Offset 0x0080 0000
Common Memory Mode Space
Offset 0x0040 0000
Attribute Memory Mode Space
Offset 0x0000 0000
Note:
The A22 pin is used to drive the REG signal of the CompactFlash Device (except in True IDE
mode).
Table 20-6.
A[23:21]
20.6.6.2
CompactFlash Mode Selection
Mode Base Address
000
Attribute Memory
010
Common Memory
100
I/O Mode
110
True IDE Mode
111
Alternate True IDE Mode
CFCE1 and CFCE2 Signals
To cover all types of access, the SMC must be alternatively set to drive 8-bit data bus or 16-bit
data bus. The odd byte access on the D[7:0] bus is only possible when the SMC is configured
to drive 8-bit memory devices on the corresponding NCS pin (NCS4 or NCS5). The Chip
Select Register (DBW field in the corresponding Chip Select Register) of the NCS4 and/or
NCS5 address space must be set as shown in Table 20-7 to enable the required access type.
NBS1 and NBS0 are the byte selection signals from SMC and are available when the SMC is
set in Byte Select mode on the corresponding Chip Select.
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The CFCE1 and CFCE2 waveforms are identical to the corresponding NCSx waveform. For
details on these waveforms and timings, refer to the Static Memory Controller section.
Table 20-7.
CFCE1 and CFCE2 Truth Table
Mode
CFCE2
CFCE1
DBW
Comment
SMC Access Mode
NBS1
NBS0
16 bits
Access to Even Byte on D[7:0]
Byte Select
NBS1
NBS0
16bits
Access to Even Byte on D[7:0]
Access to Odd Byte on D[15:8]
Byte Select
1
0
8 bits
Access to Odd Byte on D[7:0]
NBS1
NBS0
16 bits
Access to Even Byte on D[7:0]
Access to Odd Byte on D[15:8]
1
0
8 bits
Access to Odd Byte on D[7:0]
Task File
1
0
8 bits
Access to Even Byte on D[7:0]
Access to Odd Byte on D[7:0]
Data Register
1
0
16 bits
Access to Even Byte on D[7:0]
Access to Odd Byte on D[15:8]
Byte Select
Control Register
Alternate Status Read
0
1
Don’t
Care
Access to Even Byte on D[7:0]
Don’t Care
Drive Address
0
1
8 bits
Access to Odd Byte on D[7:0]
1
1
–
Attribute Memory
Common Memory
I/O Mode
Byte Select
True IDE Mode
Alternate True IDE Mode
Standby Mode or
Address Space is not
assigned to CF
20.6.6.3
–
–
Read/Write Signals
In I/O mode and True IDE 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 20-5 on page 170 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 (and/or NCS5) chip select to the appropriate values. For details on these signal waveforms, please refer to the section: Setup and Hold Cycles
of the Static Memory Controller section.
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Figure 20-5. CompactFlash Read/Write Control Signals
External Bus Interface
SMC
CompactFlash Logic
A23
1
1
0
1
0
0
CFOE
CFWE
1
1
A22
NRD_NOE
NWR0_NWE
0
1
1
Table 20-8.
CFIOR
CFIOW
1
CompactFlash Mode Selection
Mode Base Address
CFOE
CFWE
CFIOR
CFIOW
NRD
NWR0_NWE
1
1
I/O Mode
1
1
NRD
NWR0_NWE
True IDE Mode
0
1
NRD
NWR0_NWE
Attribute Memory
Common Memory
20.6.6.4
Multiplexing of CompactFlash Signals on EBI Pins
Table 20-9 on page 170 and Table 20-10 on page 171 illustrate the multiplexing of the CompactFlash logic signals with other EBI signals on the EBI pins. The EBI pins in Table 20-9 are
strictly dedicated to the CompactFlash interface as soon as the EBI0_CS4A and/or
EBI0_CS5A field of the EBI0_CSA Register in the Chip Configuration User Interface is set.
These pins must not be used to drive any other memory devices.
The EBI pins in Table 20-10 on page 171 remain shared between all memory areas when the
corresponding CompactFlash interface is enabled (EBI0_CS4A = 1 and/or EBI0_CS5A = 1).
Table 20-9.
Dedicated CompactFlash Interface Multiplexing
CompactFlash Signals
EBI Signals
Pins
CS4A = 1
NCS4/CFCS0
NCS5/CFCS1
CS5A = 1
CFCS0
CS4A = 0
CS5A = 0
NCS4
CFCS1
NCS5
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Table 20-10. Shared CompactFlash Interface Multiplexing
Access to CompactFlash Device
Access to Other EBI Devices
Pins
CompactFlash Signals
EBI Signals
NRD/CFOE
CFOE
NRD
NWR0/NWE/CFWE
CFWE
NWR0/NWE
NWR1/NBS1/CFIOR
CFIOR
NWR1/NBS1
NWR3/NBS3/CFIOW
CFIOW
NWR3/NBS3
A25/CFRNW
CFRNW
A25
20.6.6.5
Application Example
Figure 20-6 on page 171 illustrates an example of a CompactFlash application. CFCS0 and
CFRNW signals are not directly connected to the CompactFlash slot 0, but do control the
direction and the output enable of the buffers between the EBI and the CompactFlash Device.
The timing of the CFCS0 signal is identical to the 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.
Figure 20-6. CompactFlash Application Example
EBI
CompactFlash Connector
D[15:0]
D[15:0]
DIR /OE
A25/CFRNW
NCS4/CFCS0
_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
CFCE1
_CE1
CFCE2
_CE2
NWAIT
_WAIT
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20.6.7
20.6.7.1
NAND Flash Support
External Bus Interfaces 0 and 1 integrate circuitry that interfaces to NAND Flash devices.
External Bus Interface 0
The NAND Flash logic is driven by the Static Memory Controller on the NCS3 address space.
Programming the EBI0_CS3A field in the EBI0_CSA Register in the Chip Configuration User
Interface to the appropriate value enables the NAND Flash logic. For details on this register,
refer to the Bus Matrix Section. Access to an external NAND Flash device is then made by
accessing the address space reserved to NCS3 (i.e., between 0x4000 0000 and 0x4FFF
FFFF).
The NAND Flash Logic drives the read and write command signals of the SMC on the NANDOE and NANDWE signals when the NCS3 signal is active. NANDOE and NANDWE are
invalidated as soon as the transfer address fails to lie in the NCS3 address space. See Figure
”NAND Flash Signal Multiplexing on EBI Pins” on page 172 for more information. For details
on these waveforms, refer to the Static Memory Controller section.
Figure 20-7. NAND Flash Signal Multiplexing on EBI Pins
SMC
NAND Flash Logic
NCSx
NRD
NANDOE
NANDWE
NANDOE
NANDWE
NWR0_NWE
20.6.7.2
External Bus Interface 1
The NAND Flash logic is driven by the Static Memory Controller on the NCS2 address space.
Programming the EBI1_CS2A field in the EBI1_CSA Register in the Chip Configuration User
Interface to the appropriate value enables the NAND Flash logic. For details on this register,
refer to the Bus Matrix Section. Access to an external NAND Flash device is then made by
accessing the address space reserved to NCS2 (i.e., between 0x9000 0000 and 0x9FFF
FFFF).
The NAND Flash Logic drives the read and write command signals of the SMC on the NANDOE and NANDWE signals when the NCS2 signal is active. NANDOE and NANDWE are
invalidated as soon as the transfer address fails to lie in the NCS2 address space. See Figure
20-7 on page 172 for more information. For details on these waveforms, refer to the Static
Memory Controller section.
20.6.7.3
NAND Flash Signals
The address latch enable and command latch enable signals on the NAND Flash device are
driven by address bits A22 and A21 of the EBI address bus. The command, address or data
words on the data bus of the NAND Flash device are distinguished by using their address
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within the NCSx 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
NCSx is not selected, preventing the device from returning to standby mode.
Figure 20-8. NAND Flash Application Example
D[7:0]
AD[7:0]
A[22:21]
ALE
CLE
NCSx/NANDCS
Not Connected
EBI
NAND Flash
NANDOE
NANDWE
NOE
NWE
PIO
CE
PIO
R/B
Note:
The External Bus Interfaces 0 and 1 are also able to support 16-bit devices.
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20.7
Implementation Examples
The following hardware configurations are given for illustration only. The user should refer to
the memory manufacturer web site to check current device availability.
20.7.1
20.7.1.1
16-bit SDRAM
Hardware Configuration
D[0..15]
A[0..14]
(Not used A12)
U1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A13
SDA10
BA0
BA1
SDA10
BA0
BA1
A14
23
24
25
26
29
30
31
32
33
34
22
35
20
21
36
40
SDCKE
SDCK
A0
CFIOR_NBS1_NWR1
CAS
RAS
SDWE
SDCS_NCS1
SDCKE
37
SDCK
38
NBS0
NBS1
15
39
CAS
RAS
17
18
SDWE
16
19
A0 MT48LC16M16A2 DQ0
A1
DQ1
A2
DQ2
A3
DQ3
A4
DQ4
A5
DQ5
A6
DQ6
A7
DQ7
A8
DQ8
A9
DQ9
A10
DQ10
A11
DQ11
DQ12
BA0
DQ13
BA1
DQ14
DQ15
A12
N.C
VDD
VDD
CKE
VDD
VDDQ
CLK
VDDQ
VDDQ
DQML
VDDQ
DQMH
VSS
CAS
VSS
RAS
VSS
VSSQ
VSSQ
WE
VSSQ
CS
VSSQ
2
4
5
7
8
10
11
13
42
44
45
47
48
50
51
53
1
14
27
3
9
43
49
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
D10
D11
D12
D13
D14
D15
3V3
C1
C2
C3
C4
C5
C6
C7
1
1
1
1
1
1
1
28
41
54
6
12
46
52
256 Mbits
TSOP54 PACKAGE
20.7.1.2
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 depending on the 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 section “SDRAM Device Initialization”
in “SDRAM Controller (SDRAMC)”.
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20.7.2
20.7.2.1
32-bit SDRAM
Hardware Configuration
D[0..31]
A[0..14]
U1
(Not used A12)
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A13
SDA10
BA0
BA1
SDA10
BA0
BA1
A14
23
24
25
26
29
30
31
32
33
34
22
35
20
21
36
40
SDCKE
SDCK
A0
CFIOR_NBS1_NWR1
CAS
RAS
SDWE
SDCS_NCS1
SDCKE
37
SDCK
38
NBS0
NBS1
15
39
CAS
RAS
17
18
SDWE
16
19
U2
A0 MT48LC16M16A2 DQ0
A1
DQ1
A2
DQ2
A3
DQ3
A4
DQ4
A5
DQ5
A6
DQ6
A7
DQ7
A8
DQ8
A9
DQ9
A10
DQ10
A11
DQ11
DQ12
BA0
DQ13
BA1
DQ14
DQ15
A12
N.C
VDD
VDD
CKE
VDD
VDDQ
CLK
VDDQ
VDDQ
DQML
VDDQ
DQMH
VSS
CAS
VSS
RAS
VSS
VSSQ
VSSQ
WE
VSSQ
CS
VSSQ
2
4
5
7
8
10
11
13
42
44
45
47
48
50
51
53
1
14
27
3
9
43
49
28
41
54
6
12
46
52
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
D10
D11
D12
D13
D14
D15
3V3
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
SDA10
A13
BA0
BA1
A14
C1
C2
C3
C4
C5
C6
C7
100NF
100NF
100NF
100NF
100NF
100NF
100NF
A1
CFIOW_NBS3_NWR3
256 Mbits
23
24
25
26
29
30
31
32
33
34
22
35
20
21
36
40
SDCKE
37
SDCK
38
NBS2
NBS3
15
39
CAS
RAS
17
18
SDWE
16
19
A0 MT48LC16M16A2 DQ0
A1
DQ1
A2
DQ2
A3
DQ3
A4
DQ4
A5
DQ5
A6
DQ6
A7
DQ7
A8
DQ8
A9
DQ9
A10
DQ10
A11
DQ11
DQ12
BA0
DQ13
BA1
DQ14
DQ15
A12
N.C
VDD
VDD
CKE
VDD
VDDQ
CLK
VDDQ
VDDQ
DQML
VDDQ
DQMH
VSS
CAS
VSS
RAS
VSS
VSSQ
VSSQ
WE
VSSQ
CS
VSSQ
2
4
5
7
8
10
11
13
42
44
45
47
48
50
51
53
1
14
27
3
9
43
49
D16
D17
D18
D19
D20
D21
D22
D23
D24
D25
D26
D27
D28
D29
D30
D31
3V3
C8
C9
C10
C11
C12
C13
C14
100NF
100NF
100NF
100NF
100NF
100NF
100NF
28
41
54
6
12
46
52
256 Mbits
TSOP54 PACKAGE
20.7.2.2
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 depending on the 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 section “SDRAM Device Initialization”
in “SDRAM Controller (SDRAMC)”.
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20.7.3
20.7.3.1
8-bit NANDFlash
Hardware Configuration
D[0..7]
U1
CLE
ALE
NANDOE
NANDWE
(ANY PIO)
(ANY PIO)
R1
3V3
R2
10K
16
17
8
18
9
CLE
ALE
RE
WE
CE
7
R/B
19
WP
10K
1
2
3
4
5
6
10
11
14
15
20
21
22
23
24
25
26
K9F2G08U0M
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
I/O0
I/O1
I/O2
I/O3
I/O4
I/O5
I/O6
I/O7
29
30
31
32
41
42
43
44
N.C
N.C
N.C
N.C
N.C
N.C
PRE
N.C
N.C
N.C
N.C
N.C
48
47
46
45
40
39
38
35
34
33
28
27
VCC
VCC
37
12
VSS
VSS
36
13
2 Gb
D0
D1
D2
D3
D4
D5
D6
D7
3V3
C2
100NF
C1
100NF
TSOP48 PACKAGE
20.7.3.2
Software Configuration
The following configuration has to be performed:
• Assign the EBI CS3 to the NANDFlash by setting the bit EBI_CS3A in the EBI Chip Select
Assignment Register located in the bus matrix memory space
• Reserve A21 / A22 for ALE / CLE functions. Address and Command Latches are controlled
respectively by setting to 1 the address bit A21 and A22 during accesses.
• NANDOE and NANDWE 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 input to manage the Ready/Busy signal.
• Configure Static Memory Controller CS3 Setup, Pulse, Cycle and Mode accordingly to
NANDFlash timings, the data bus width and the system bus frequency.
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AT91SAM9263 Preliminary
20.7.4
20.7.4.1
16-bit NANDFlash
Hardware Configuration
D[0..15]
U1
CLE
ALE
NANDOE
NANDWE
(ANY PIO)
(ANY PIO)
R1
3V3
R2
10K
16
17
8
18
9
CLE
ALE
RE
WE
CE
7
R/B
19
WP
1
2
3
4
5
6
10
11
14
15
20
21
22
23
24
34
35
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
N.C
10K
MT29F2G16AABWP-ET
I/O0 26
I/O1 28
I/O2 30
I/O3 32
I/O4 40
I/O5 42
I/O6 44
I/O7 46
I/O8 27
I/O9 29
I/O10 31
I/O11 33
I/O12 41
I/O13 43
I/O14 45
I/O15 47
N.C
PRE
N.C
39
38
36
VCC
VCC
37
12
VSS
VSS
VSS
48
25
13
2 Gb
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
D10
D11
D12
D13
D14
D15
3V3
C2
100NF
C1
100NF
TSOP48 PACKAGE
20.7.4.2
Software Configuration
The software configuration is the same as for an 8-bit NANDFlash except the data bus width
programmed in the mode register of the Static Memory Controller.
177
6249B–ATARM–14-Dec-06
20.7.5
20.7.5.1
NOR Flash on NCS0
Hardware Configuration
D[0..15]
A[1..22]
U1
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12
A13
A14
A15
A16
A17
A18
A19
A20
A21
A22
NRST
NWE
3V3
NCS0
NRD
25
24
23
22
21
20
19
18
8
7
6
5
4
3
2
1
48
17
16
15
10
9
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12
A13
A14
A15
A16
A17
A18
A19
A20
A21
12
11
14
13
26
28
RESET
WE
WP
VPP
CE
OE
DQ0
DQ1
DQ2
DQ3
DQ4
DQ5
DQ6
DQ7
DQ8
DQ9
DQ10
DQ11
DQ12
DQ13
DQ14
DQ15
29
31
33
35
38
40
42
44
30
32
34
36
39
41
43
45
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
D10
D11
D12
D13
D14
D15
AT49BV6416
3V3
VCCQ
47
VCC
37
VSS
VSS
46
27
C2
100NF
C1
100NF
TSOP48 PACKAGE
20.7.5.2
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 16-bit non-volatile memory at slow clock.
For another configuration, configure the Static Memory Controller CS0 Setup, Pulse, Cycle
and Mode depending on Flash timings and system bus frequency.
178
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
20.7.6
20.7.6.1
Compact Flash
Hardware Configuration
MEMORY & I/O MODE
D[0..15]
MN1A
D15
D14
D13
D12
D11
D10
D9
D8
A2
A1
B2
B1
C2
C1
D2
D1
1B1
1B2
1B3
1B4
1B5
1B6
1B7
1B8
A3
A4
1DIR
1OE
1A1
1A2
1A3
1A4
1A5
1A6
1A7
1A8
CF_D15
CF_D14
CF_D13
CF_D12
CF_D11
CF_D10
CF_D9
CF_D8
E5
E6
F5
F6
G5
G6
H5
H6
CF_D7
CF_D6
CF_D5
CF_D4
CF_D3
CF_D2
CF_D1
CF_D0
74ALVCH32245
MN1B
D7
D6
D5
D4
D3
D2
D1
D0
A25/CFRNW
4
CFCSx
(CFCS0 or CFCS1)
6
5
E2
E1
F2
F1
G2
G1
H2
H1
2B1
2B2
2B3
2B4
2B5
2B6
2B7
2B8
H3
H4
2DIR
2OE
2A1
2A2
2A3
2A4
2A5
2A6
2A7
2A8
3V3
R1
MN2A
47K
SN74ALVC32
74ALVCH32245
MN2B
SN74ALVC32
R2
47K
CD2
1
3
(ANY PIO)
CD1
2
CARD DETECT
CF_D15
CF_D14
CF_D13
CF_D12
CF_D11
CF_D10
CF_D9
CF_D8
CF_D7
CF_D6
CF_D5
CF_D4
CF_D3
CF_D2
CF_D1
CF_D0
31
30
29
28
27
49
48
47
6
5
4
3
2
23
22
21
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
CD2
CD1
25
26
CD2#
CD1#
CF_A10
CF_A9
CF_A8
CF_A7
CF_A6
CF_A5
CF_A4
CF_A3
CF_A2
CF_A1
CF_A0
8
10
11
12
14
15
16
17
18
19
20
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
REG
44
REG#
WE
OE
IOWR
IORD
36
9
35
34
WE#
OE#
IOWR#
IORD#
CE2
CE1
32
7
CE2#
CE1#
MN1C
A[0..10]
A10
A9
A8
A7
A6
A5
A4
A3
J5
J6
K5
K6
L5
L6
M5
M6
3A1
3A2
3A3
3A4
3A5
3A6
3A7
3A8
J3
J4
3DIR
3OE
3V3
3B1
3B2
3B3
3B4
3B5
3B6
3B7
3B8
J2
J1
K2
K1
L2
L1
M2
M1
CF_A10
CF_A9
CF_A8
CF_A7
CF_A6
CF_A5
CF_A4
CF_A3
74ALVCH32245
MN1D
A2
A1
A0
A22/REG
CFWE
CFOE
CFIOW
CFIOR
N5
N6
P5
P6
R5
R6
T6
T5
4A1
4A2
4A3
4A4
4A5
4A6
4A7
4A8
T3
T4
4DIR
4OE
3V3
J1
A5
A6
B5
B6
C5
C6
D5
D6
4B1
4B2
4B3
4B4
4B5
4B6
4B7
4B8
N2
N1
P2
P1
R2
R1
T1
T2
CF_A2
CF_A1
CF_A0
REG
WE
OE
IOWR
IORD
VCC
38
VCC
13
GND
GND
50
1
CSEL#
39
INPACK#
43
BVD2
BVD1
45
46
24
WP
WAIT#
42
WAIT#
VS2#
VS1#
40
33
RESET
41
RESET
RDY/BSY
37
C1
100NF
C2
100NF
RDY/BSY
N7E50-7516VY-20
1
74ALVCH32245
2
CFCE1
5
10
4
CFCE2
9
(ANY PIO)
CFIRQ
11
13
(ANY PIO)
CFRST
MN3A
SN74ALVC125
3
CE2
MN3B
SN74ALVC125
6
CE1
MN3C
SN74ALVC125
RESET
8
MN3D
R3
SN74ALVC125
10K
RDY/BSY
12
3V3
MN4
3V3
NWAIT
5 VCC
1
4
2
GND
R4
10K
WAIT#
3V3
3
SN74LVC1G125-Q1
179
6249B–ATARM–14-Dec-06
20.7.6.2
Software Configuration
The following configuration has to be performed:
• Assign the EBI CS4 and/or EBI_CS5 to the CompactFlash Slot 0 or/and Slot 1 by setting
the bit EBI_CS4A or/and EBI_CS5A 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, CFS0, CFCS1, 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 and/or SMC_CS5 (for Slot 0 or 1) Setup, Pulse, Cycle and Mode
accordingly to Compact Flash timings and system bus frequency.
180
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
20.7.7
20.7.7.1
Compact Flash True IDE
Hardware Configuration
TRUE IDE MODE
D[0..15]
MN1A
D15
D14
D13
D12
D11
D10
D9
D8
A2
A1
B2
B1
C2
C1
D2
D1
A3
A4
1B1
1B2
1B3
1B4
1B5
1B6
1B7
1B8
CF_D15
CF_D14
CF_D13
CF_D12
CF_D11
CF_D10
CF_D9
CF_D8
E5
E6
F5
F6
G5
G6
H5
H6
CF_D7
CF_D6
CF_D5
CF_D4
CF_D3
CF_D2
CF_D1
CF_D0
1DIR
1OE
74ALVCH32245
MN1B
D7
D6
D5
D4
D3
D2
D1
D0
A25/CFRNW
CFCSx
(CFCS0 or CFCS1)
4
6
5
E2
E1
F2
F1
G2
G1
H2
H1
2B1
2B2
2B3
2B4
2B5
2B6
2B7
2B8
H3
H4
2DIR
2OE
2A1
2A2
2A3
2A4
2A5
2A6
2A7
2A8
3V3
R1
MN2A
47K
SN74ALVC32
74ALVCH32245
MN2B
SN74ALVC32
CD2
1
CD1
2
CARD DETECT
J5
J6
K5
K6
L5
L6
M5
M6
3A1
3A2
3A3
3A4
3A5
3A6
3A7
3A8
J3
J4
3DIR
3OE
3V3
3B1
3B2
3B3
3B4
3B5
3B6
3B7
3B8
J2
J1
K2
K1
L2
L1
M2
M1
CF_A10
CF_A9
CF_A8
CF_A7
CF_A6
CF_A5
CF_A4
CF_A3
74ALVCH32245
MN1D
A2
A1
A0
A22/REG
CFWE
CFOE
CFIOW
CFIOR
N5
N6
P5
P6
R5
R6
T6
T5
4A1
4A2
4A3
4A4
4A5
4A6
4A7
4A8
T3
T4
4DIR
4OE
31
30
29
28
27
49
48
47
6
5
4
3
2
23
22
21
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
CD2
CD1
25
26
CD2#
CD1#
CF_A2
CF_A1
CF_A0
8
10
11
12
14
15
16
17
18
19
20
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
44
REG#
IOWR
IORD
36
9
35
34
WE#
ATA SEL#
IOWR#
IORD#
CE2
CE1
32
7
CS1#
CS0#
3V3
MN1C
A10
A9
A8
A7
A6
A5
A4
A3
CF_D15
CF_D14
CF_D13
CF_D12
CF_D11
CF_D10
CF_D9
CF_D8
CF_D7
CF_D6
CF_D5
CF_D4
CF_D3
CF_D2
CF_D1
CF_D0
R2
47K
3
(ANY PIO)
A[0..10]
3V3
J1
1A1
1A2
1A3
1A4
1A5
1A6
1A7
1A8
A5
A6
B5
B6
C5
C6
D5
D6
4B1
4B2
4B3
4B4
4B5
4B6
4B7
4B8
N2
N1
P2
P1
R2
R1
T1
T2
CF_A2
CF_A1
CF_A0
REG
WE
OE
IOWR
IORD
24
IOIS16#
IORDY
42
IORDY
RESET#
41
VCC
38
VCC
13
GND
GND
50
1
CSEL#
39
INPACK#
43
DASP#
PDIAG#
45
46
VS2#
VS1#
40
33
INTRQ
37
RESET#
C1
100NF
C2
100NF
INTRQ
N7E50-7516VY-20
1
74ALVCH32245
2
CFCE1
5
10
4
CFCE2
9
(ANY PIO)
CFIRQ
11
13
(ANY PIO)
CFRST
MN3A
SN74ALVC125
3
CE2
MN3B
SN74ALVC125
6
CE1
MN3C
SN74ALVC125
RESET#
8
MN3D
SN74ALVC125
INTRQ
12
R3
10K
3V3
MN4
3V3
NWAIT
5 VCC
1
4
2
GND
R4
10K
IORDY
3V3
3
SN74LVC1G125-Q1
181
6249B–ATARM–14-Dec-06
20.7.7.2
Software Configuration
The following configuration has to be performed:
• Assign the EBI CS4 and/or EBI_CS5 to the CompactFlash Slot 0 or/and Slot 1 by setting
the bit EBI_CS4A or/and EBI_CS5A in the EBI Chip Select Assignment Register located in
the bus matrix memory space.
• The address line A21 is to select Alternate True IDE (A21=1) or True IDE (A21=0) modes.
• CFRNW, CFS0, CFCS1, 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 and/or SMC_CS5 (for Slot 0 or 1) Setup, Pulse, Cycle and Mode
accordingly to Compact Flash timings and system bus frequency.
182
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
21. Static Memory Controller (SMC)
21.1
Description
The Static Memory Controller (SMC) generates the signals that control the access to the external memory devices or peripheral devices. It has 8 Chip Selects and a 26-bit address bus. The
32-bit data bus can be configured to interface with 8-, 16-, or 32-bit external devices. Separate
read and write control signals allow for direct memory and peripheral interfacing. Read and write
signal waveforms are fully parametrizable.
The SMC can manage wait requests from external devices to extend the current access. The
SMC is provided with an automatic slow clock mode. In slow clock mode, it switches from userprogrammed waveforms to slow-rate specific waveforms on read and write signals. The SMC
supports asynchronous burst read in page mode access for page size up to 32 bytes.
21.2
I/O Lines Description
Table 21-1.
I/O Line 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
A0/NBS0
Address Bit 0/Byte 0 Select Signal
Output
Low
NWR1/NBS1
Write 1/Byte 1 Select Signal
Output
Low
A1/NWR2/NBS2
Address Bit 1/Write 2/Byte 2 Select Signal
Output
Low
NWR3/NBS3
Write 3/Byte 3 Select Signal
Output
Low
A[25:2]
Address Bus
Output
D[31:0]
Data Bus
NWAIT
External Wait Signal
21.3
I/O
Input
Low
Multiplexed Signals
Table 21-2.
Static Memory Controller (SMC) Multiplexed Signals
Multiplexed Signals
Related Function
NWR0
NWE
Byte-write or byte-select access, see “Byte Write or Byte Select Access” on page 185
A0
NBS0
8-bit or 16-/32-bit data bus, see “Data Bus Width” on page 185
NWR1
NBS1
Byte-write or byte-select access see “Byte Write or Byte Select Access” on page 185
A1
NWR2
NWR3
NBS3
NBS2
8-/16-bit or 32-bit data bus, see “Data Bus Width” on page 185.
Byte-write or byte-select access, see “Byte Write or Byte Select Access” on page 185
Byte-write or byte-select access see “Byte Write or Byte Select Access” on page 185
183
6249B–ATARM–14-Dec-06
21.4
21.4.1
Application Example
Hardware Interface
Figure 21-1. SMC Connections to Static Memory Devices
D0-D31
A0/NBS0
NWR0/NWE
NWR1/NBS1
A1/NWR2/NBS2
NWR3/NBS3
D0 - D7
128K x 8
SRAM
D8-D15
D0 - D7
CS
NRD
NWR0/NWE
A2 - A25
A2 - A18
A0 - A16
NRD
OE
NWR1/NBS1
WE
128K x 8
SRAM
D16 - D23
D24-D31
D0 - D7
A0 - A16
NRD
Static Memory
Controller
21.5
21.5.1
A2 - A18
OE
WE
128K x 8
SRAM
D0-D7
CS
CS
A1/NWR2/NBS2
D0-D7
CS
A0 - A16
NCS0
NCS1
NCS2
NCS3
NCS4
NCS5
NCS6
NCS7
128K x 8
SRAM
A2 - A18
A2 - A18
A0 - A16
NRD
OE
WE
OE
NWR3/NBS3
WE
Product Dependencies
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 SMC are not used by the application,
they can be used for other putposes by the PIO Controller.
184
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
21.6
External Memory Mapping
The SMC provides up to 26 address lines, A[25:0]. This allows each chip select line to address
up to 64 Mbytes of memory.
If the physical memory device connected on one chip select is smaller than 64 Mbytes, it wraps
around and appears to be repeated within this space. The SMC correctly handles any valid
access to the memory device within the page (see Figure 21-1).
A[25:0] is only significant for 8-bit memory, A[25:1] is used for 16-bit memory, A[25:2] is used for
32-bit memory.
Figure 21-2.
Memory Connections for Eight External Devices
NCS[0] - NCS[7]
NCS7
NRD
SMC
NCS6
NWE
NCS5
A[25:0]
NCS4
D[31:0]
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[25:0]
8 or 16 or 32
21.7
21.7.1
D[31:0] or D[15:0] or
D[7:0]
Connection to External Devices
Data Bus Width
A data bus width of 8, 16, or 32 bits can be selected for each chip select. This option is controlled by the field DBW in SMC_MODE (Mode Register) for the corresponding chip select.
Figure 21-3 shows how to connect a 512K x 8-bit memory on NCS2. Figure 21-4 shows how to
connect a 512K x 16-bit memory on NCS2. Figure 21-5 shows two 16-bit memories connected
as a single 32-bit memory
21.7.2
Byte Write or Byte Select Access
Each chip select with a 16-bit or 32-bit data bus can operate with one of two different types of
write access: byte write or byte select access. This is controlled by the BAT field of the
SMC_MODE register for the corresponding chip select.
185
6249B–ATARM–14-Dec-06
Figure 21-3.
Memory Connection for an 8-bit Data Bus
D[7:0]
D[7:0]
A[18:2]
A[18:2]
SMC
A0
A0
A1
A1
NWE
Write Enable
NRD
Output Enable
NCS[2]
Figure 21-4.
Memory Enable
Memory Connection for a 16-bit Data Bus
D[15:0]
D[15:0]
A[19:2]
A[18:1]
A1
SMC
A[0]
NBS0
Low Byte Enable
NBS1
High Byte Enable
NWE
Write Enable
NRD
Output Enable
NCS[2]
Memory Enable
Figure 21-5. Memory Connection for a 32-bit Data Bus
D[31:16]
SMC
D[15:0]
D[15:0]
A[20:2]
A[18:0]
NBS0
Byte 0 Enable
NBS1
Byte 1 Enable
NBS2
Byte 2 Enable
NBS3
Byte 3 Enable
NWE
Write Enable
NRD
Output Enable
NCS[2]
186
D[31:16]
Memory Enable
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
21.7.2.1
Byte Write Access
Byte write access supports one byte write signal per byte of the data bus and a single read
signal.
• For 16-bit devices: the SMC provides NWR0 and NWR1 write signals for respectively byte0
(lower byte) and byte1 (upper byte) of a 16-bit bus. One single read signal (NRD) is provided.
Byte Write Access is used to connect 2 x 8-bit devices as a 16-bit memory.
• For 32-bit devices: NWR0, NWR1, NWR2 and NWR3, are the write signals of byte0 (lower
byte), byte1, byte2 and byte 3 (upper byte) respectively. One single read signal (NRD) is
provided.
Byte Write Access is used to connect 4 x 8-bit devices as a 32-bit memory.
Byte Write option is illustrated on Figure 21-6.
21.7.2.2
Byte Select Access
In this mode, read/write operations can be enabled/disabled at a byte level. One byte-select line
per byte of the data bus is provided. One NRD and one NWE signal control read and write.
• For 16-bit devices: the SMC provides NBS0 and NBS1 selection signals for respectively
byte0 (lower byte) and byte1 (upper byte) of a 16-bit bus.
Byte Select Access is used to connect one 16-bit device.
• For 32-bit devices: NBS0, NBS1, NBS2 and NBS3, are the selection signals of byte0 (lower
byte), byte1, byte2 and byte 3 (upper byte) respectively. Byte Select Access is used to
connect two 16-bit devices.
Figure 21-7 shows how to connect two 16-bit devices on a 32-bit data bus in Byte Select Access
mode, on NCS3 (BAT = Byte Select Access).
Figure 21-6.
Connection of 2 x 8-bit Devices on a 16-bit Bus: Byte Write Option
D[7:0]
D[7:0]
D[15:8]
A[24:2]
SMC
A1
NWR0
A[23:1]
A[0]
Write Enable
NWR1
NRD
NCS[3]
Read Enable
Memory Enable
D[15:8]
A[23:1]
A[0]
Write Enable
Read Enable
Memory Enable
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21.7.2.3
Signal Multiplexing
Depending on the BAT, only the write signals or the byte select signals are used. To save IOs at
the external bus interface, control signals at the SMC interface are multiplexed. Table 21-3
shows signal multiplexing depending on the data bus width and the byte access type.
For 32-bit devices, bits A0 and A1 are unused. For 16-bit devices, bit A0 of address is unused.
When Byte Select Option is selected, NWR1 to NWR3 are unused. When Byte Write option is
selected, NBS0 to NBS3 are unused.
Figure 21-7. Connection of 2x16-bit Data Bus on a 32-bit Data Bus (Byte Select Option)
D[15:0]
D[15:0]
D[31:16]
A[25:2]
SMC
A[23:0]
NWE
Write Enable
NBS0
Low Byte Enable
NBS1
High Byte Enable
NBS2
NBS3
Read Enable
NRD
Memory Enable
NCS[3]
D[31:16]
A[23:0]
Write Enable
Low Byte Enable
High Byte Enable
Read Enable
Memory Enable
Table 21-3.
SMC Multiplexed Signal Translation
Signal Name
Device Type
32-bit Bus
16-bit Bus
8-bit Bus
1x32-bit
2x16-bit
4 x 8-bit
1x16-bit
2 x 8-bit
Byte Select
Byte Select
Byte Write
Byte Select
Byte Write
NBS0_A0
NBS0
NBS0
NWE_NWR0
NWE
NWE
NWR0
NWE
NWR0
NBS1_NWR1
NBS1
NBS1
NWR1
NBS1
NWR1
NBS2_NWR2_A1
NBS2
NBS2
NWR2
A1
A1
NBS3_NWR3
NBS3
NBS3
NWR3
Byte Access Type (BAT)
188
NBS0
1 x 8-bit
A0
NWE
A1
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21.8
Standard Read and Write Protocols
In the following sections, the byte access type is not considered. Byte select lines (NBS0 to
NBS3) always have the same timing as the A address bus. NWE represents either the NWE signal in byte select access type or one of the byte write lines (NWR0 to NWR3) in byte write
access type. NWR0 to NWR3 have the same timings and protocol as NWE. In the same way,
NCS represents one of the NCS[0..7] chip select lines.
21.8.1
Read Waveforms
The read cycle is shown on Figure 21-8.
The read cycle starts with the address setting on the memory address bus, i.e.:
{A[25:2], A1, A0} for 8-bit devices
{A[25:2], A1} for 16-bit devices
A[25:2] for 32-bit devices.
Figure 21-8. Standard Read Cycle
MCK
A[25:2]
NBS0,NBS1,
NBS2,NBS3,
A0, A1
NRD
NCS
D[31:0]
NRD_SETUP
NCS_RD_SETUP
NRD_PULSE
NCS_RD_PULSE
NRD_HOLD
NCS_RD_HOLD
NRD_CYCLE
21.8.1.1
NRD Waveform
The NRD signal is characterized by a setup timing, a pulse width and a hold timing.
1. NRD_SETUP: the NRD setup time is defined as the setup of address before the NRD
falling edge;
2. NRD_PULSE: the NRD pulse length is the time between NRD falling edge and NRD
rising edge;
3. NRD_HOLD: the NRD hold time is defined as the hold time of address after the NRD
rising edge.
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21.8.1.2
NCS Waveform
Similarly, the NCS signal can be divided into a setup time, pulse length and hold time:
1. NCS_RD_SETUP: the NCS setup time is defined as the setup time of address before
the NCS falling edge.
2. NCS_RD_PULSE: the NCS pulse length is the time between NCS falling edge and
NCS rising edge;
3. NCS_RD_HOLD: the NCS hold time is defined as the hold time of address after the
NCS rising edge.
21.8.1.3
Read Cycle
The NRD_CYCLE time is defined as the total duration of the read cycle, i.e., from the time where
address is set on the address bus to the point where address may change. The total read cycle
time is equal to:
NRD_CYCLE = NRD_SETUP + NRD_PULSE + NRD_HOLD
= NCS_RD_SETUP + NCS_RD_PULSE + NCS_RD_HOLD
All NRD and NCS timings are defined separately for each chip select as an integer number of
Master Clock cycles. To ensure that the NRD and NCS timings are coherent, user must define
the total read cycle instead of the hold timing. NRD_CYCLE implicitly defines the NRD hold time
and NCS hold time as:
NRD_HOLD = NRD_CYCLE - NRD SETUP - NRD PULSE
NCS_RD_HOLD = NRD_CYCLE - NCS_RD_SETUP - NCS_RD_PULSE
21.8.1.4
190
Null Delay Setup and Hold
If null setup and hold parameters are programmed for NRD and/or NCS, NRD and NCS remain
active continuously in case of consecutive read cycles in the same memory (see Figure 21-9).
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Figure 21-9. No Setup, No Hold On NRD and NCS Read Signals
MCK
A[25:2]
NBS0,NBS1,
NBS2,NBS3,
A0, A1
NRD
NCS
D[31:0]
NRD_PULSE
NCS_RD_PULSE
NRD_CYCLE
21.8.1.5
NRD_PULSE
NCS_RD_PULSE
NRD_CYCLE
NRD_PULSE
NCS_RD_PULSE
NRD_CYCLE
Null Pulse
Programming null pulse is not permitted. Pulse must be at least set to 1. A null value leads to
unpredictable behavior.
21.8.2
Read Mode
As NCS and NRD waveforms are defined independently of one other, the SMC needs to know
when the read data is available on the data bus. The SMC does not compare NCS and NRD timings to know which signal rises first. The READ_MODE parameter in the SMC_MODE register
of the corresponding chip select indicates which signal of NRD and NCS controls the read
operation.
21.8.2.1
Read is Controlled by NRD (READ_MODE = 1):
Figure 21-10 shows the waveforms of a read operation of a typical asynchronous RAM. The
read data is available tPACC after the falling edge of NRD, and turns to ‘Z’ after the rising edge of
NRD. In this case, the READ_MODE must be set to 1 (read is controlled by NRD), to indicate
that data is available with the rising edge of NRD. The SMC samples the read data internally on
the rising edge of Master Clock that generates the rising edge of NRD, whatever the programmed waveform of NCS may be.
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Figure 21-10. READ_MODE = 1: Data is sampled by SMC before the rising edge of NRD
MCK
A[25:2]
NBS0,NBS1,
NBS2,NBS3,
A0, A1
NRD
NCS
tPACC
D[31:0]
Data Sampling
21.8.2.2
Read is Controlled by NCS (READ_MODE = 0)
Figure 21-11 shows the typical read cycle of an LCD module. The read data is valid tPACC after
the falling edge of the NCS signal and remains valid until the rising edge of NCS. Data must be
sampled when NCS is raised. In that case, the READ_MODE must be set to 0 (read is controlled
by NCS): the SMC internally samples the data on the rising edge of Master Clock that generates
the rising edge of NCS, whatever the programmed waveform of NRD may be.
Figure 21-11. READ_MODE = 0: Data is sampled by SMC before the rising edge of NCS
MCK
A[25:2]
NBS0,NBS1,
NBS2,NBS3,
A0, A1
NRD
NCS
tPACC
D[31:0]
Data Sampling
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21.8.3
21.8.3.1
Write Waveforms
The write protocol is similar to the read protocol. It is depicted in Figure 21-12. The write cycle
starts with the address setting on the memory address bus.
NWE Waveforms
The NWE signal is characterized by a setup timing, a pulse width and a hold timing.
1. NWE_SETUP: the NWE setup time is defined as the setup of address and data before
the NWE falling edge;
2. NWE_PULSE: The NWE pulse length is the time between NWE falling edge and NWE
rising edge;
3. NWE_HOLD: The NWE hold time is defined as the hold time of address and data after
the NWE rising edge.
The NWE waveforms apply to all byte-write lines in Byte Write access mode: NWR0 to NWR3.
21.8.3.2
NCS Waveforms
The NCS signal waveforms in write operation are not the same that those applied in read operations, but are separately defined:
1. NCS_WR_SETUP: the NCS setup time is defined as the setup time of address before
the NCS falling edge.
2. NCS_WR_PULSE: the NCS pulse length is the time between NCS falling edge and
NCS rising edge;
3. NCS_WR_HOLD: the NCS hold time is defined as the hold time of address after the
NCS rising edge.
Figure 21-12. Write Cycle
MCK
A[25:2]
NBS0, NBS1,
NBS2, NBS3,
A0, A1
NWE
NCS
NWE_SETUP
NCS_WR_SETUP
NWE_PULSE
NCS_WR_PULSE
NWE_HOLD
NCS_WR_HOLD
NWE_CYCLE
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21.8.3.3
Write Cycle
The write_cycle time is defined as the total duration of the write cycle, that is, from the time
where address is set on the address bus to the point where address may change. The total write
cycle time is equal to:
NWE_CYCLE = NWE_SETUP + NWE_PULSE + NWE_HOLD
= NCS_WR_SETUP + NCS_WR_PULSE + NCS_WR_HOLD
All NWE and NCS (write) timings are defined separately for each chip select as an integer number of Master Clock cycles. To ensure that the NWE and NCS timings are coherent, the user
must define the total write cycle instead of the hold timing. This implicitly defines the NWE hold
time and NCS (write) hold times as:
NWE_HOLD = NWE_CYCLE - NWE_SETUP - NWE_PULSE
NCS_WR_HOLD = NWE_CYCLE - NCS_WR_SETUP - NCS_WR_PULSE
21.8.3.4
Null Delay Setup and Hold
If null setup parameters are programmed for NWE and/or NCS, NWE and/or NCS remain active
continuously in case of consecutive write cycles in the same memory (see Figure 21-13). However, for devices that perform write operations on the rising edge of NWE or NCS, such as
SRAM, either a setup or a hold must be programmed.
Figure 21-13. Null Setup and Hold Values of NCS and NWE in Write Cycle
MCK
A[25:2]
NBS0, NBS1,
NBS2, NBS3,
A0, A1
NWE,
NWR0, NWR1,
NWR2, NWR3
NCS
D[31:0]
NWE_PULSE
21.8.3.5
NWE_PULSE
NWE_PULSE
NCS_WR_PULSE
NCS_WR_PULSE
NCS_WR_PULSE
NWE_CYCLE
NWE_CYCLE
NWE_CYCLE
Null Pulse
Programming null pulse is not permitted. Pulse must be at least set to 1. A null value leads to
unpredictable behavior.
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21.8.4
Write Mode
The WRITE_MODE parameter in the SMC_MODE register of the corresponding chip select indicates which signal controls the write operation.
21.8.4.1
Write is Controlled by NWE (WRITE_MODE = 1):
Figure 21-14 shows the waveforms of a write operation with WRITE_MODE set to 1. The data is
put on the bus during the pulse and hold steps of the NWE signal. The internal data buffers are
turned out after the NWE_SETUP time, and until the end of the write cycle, regardless of the
programmed waveform on NCS.
Figure 21-14. WRITE_MODE = 1. The write operation is controlled by NWE
MCK
A[25:2]
NBS0, NBS1,
NBS2, NBS3,
A0, A1
NWE,
NWR0, NWR1,
NWR2, NWR3
NCS
D[31:0]
21.8.4.2
Write is Controlled by NCS (WRITE_MODE = 0)
Figure 21-15 shows the waveforms of a write operation with WRITE_MODE set to 0. The data is
put on the bus during the pulse and hold steps of the NCS signal. The internal data buffers are
turned out after the NCS_WR_SETUP time, and until the end of the write cycle, regardless of
the programmed waveform on NWE.
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Figure 21-15. WRITE_MODE = 0. The write operation is controlled by NCS
MCK
A[25:2]
NBS0, NBS1,
NBS2, NBS3,
A0, A1
NWE,
NWR0, NWR1,
NWR2, NWR3
NCS
D[31:0]
21.8.5
Coding Timing Parameters
All timing parameters are defined for one chip select and are grouped together in one
SMC_REGISTER according to their type.
The SMC_SETUP register groups the definition of all setup parameters:
• NRD_SETUP, NCS_RD_SETUP, NWE_SETUP, NCS_WR_SETUP
The SMC_PULSE register groups the definition of all pulse parameters:
• NRD_PULSE, NCS_RD_PULSE, NWE_PULSE, NCS_WR_PULSE
The SMC_CYCLE register groups the definition of all cycle parameters:
• NRD_CYCLE, NWE_CYCLE
Table 21-4 shows how the timing parameters are coded and their permitted range.
Table 21-4.
Coding and Range of Timing Parameters
Permitted Range
196
Coded Value
Number of Bits
Effective Value
Coded Value
Effective Value
setup [5:0]
6
128 x setup[5] + setup[4:0]
0 ≤≤31
128 ≤≤128+31
pulse [6:0]
7
256 x pulse[6] + pulse[5:0]
0 ≤≤63
256 ≤≤256+63
cycle [8:0]
9
256 x cycle[8:7] + cycle[6:0]
0 ≤≤127
256 ≤≤256+127
512 ≤≤512+127
768 ≤≤768+127
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21.8.6
Reset Values of Timing Parameters
Table 21-5 gives the default value of timing parameters at reset.
Table 21-5.
21.8.7
Reset Values of Timing Parameters
Register
Reset Value
SMC_SETUP
0x01010101
All setup timings are set to 1
SMC_PULSE
0x01010101
All pulse timings are set to 1
SMC_CYCLE
0x00030003
The read and write operation last 3 Master Clock cycles and
provide one hold cycle
WRITE_MODE
1
Write is controlled with NWE
READ_MODE
1
Read is controlled with NRD
Usage Restriction
The SMC does not check the validity of the user-programmed parameters. If the sum of SETUP
and PULSE parameters is larger than the corresponding CYCLE parameter, this leads to unpredictable behavior of the SMC.
For read operations:
Null but positive setup and hold of address and NRD and/or NCS can not be guaranteed at the
memory interface because of the propagation delay of theses signals through external logic and
pads. If positive setup and hold values must be verified, then it is strictly recommended to program non-null values so as to cover possible skews between address, NCS and NRD signals.
For write operations:
If a null hold value is programmed on NWE, the SMC can guarantee a positive hold of address,
byte select lines, and NCS signal after the rising edge of NWE. This is true for WRITE_MODE =
1 only. See “Early Read Wait State” on page 198.
For read and write operations: a null value for pulse parameters is forbidden and may lead to
unpredictable behavior.
In read and write cycles, the setup and hold time parameters are defined in reference to the
address bus. For external devices that require setup and hold time between NCS and NRD signals (read), or between NCS and NWE signals (write), these setup and hold times must be
converted into setup and hold times in reference to the address bus.
21.9
Automatic Wait States
Under certain circumstances, the SMC automatically inserts idle cycles between accesses to
avoid bus contention or operation conflict.
21.9.1
Chip Select Wait States
The SMC always inserts an idle cycle between 2 transfers on separate chip selects. This idle
cycle ensures that there is no bus contention between the de-activation of one device and the
activation of the next one.
During chip select wait state, all control lines are turned inactive: NBS0 to NBS3, NWR0 to
NWR3, NCS[0..7], NRD lines are all set to 1.
Figure 21-16 illustrates a chip select wait state between access on Chip Select 0 and Chip
Select 2.
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Figure 21-16. Chip Select Wait State between a Read Access on NCS0 and a Write Access on NCS2
MCK
A[25:2]
NBS0, NBS1,
NBS2, NBS3,
A0,A1
NRD
NWE
NCS0
NCS2
NWE_CYCLE
NRD_CYCLE
D[31:0]
Read to Write Chip Select
Wait State
Wait State
21.9.2
Early Read Wait State
In some cases, the SMC inserts a wait state cycle between a write access and a read access to
allow time for the write cycle to end before the subsequent read cycle begins. This wait state is
not generated in addition to a chip select wait state. The early read cycle thus only occurs
between a write and read access to the same memory device (same chip select).
An early read wait state is automatically inserted if at least one of the following conditions is
valid:
• if the write controlling signal has no hold time and the read controlling signal has no setup
time (Figure 21-17).
• in NCS write controlled mode (WRITE_MODE = 0), if there is no hold timing on the NCS
signal and the NCS_RD_SETUP parameter is set to 0, regardless of the read mode (Figure
21-18). The write operation must end with a NCS rising edge. Without an Early Read Wait
State, the write operation could not complete properly.
• in NWE controlled mode (WRITE_MODE = 1) and if there is no hold timing (NWE_HOLD =
0), the feedback of the write control signal is used to control address, data, chip select and
byte select lines. If the external write control signal is not inactivated as expected due to load
capacitances, an Early Read Wait State is inserted and address, data and control signals are
maintained one more cycle. See Figure 21-19.
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Figure 21-17. Early Read Wait State: Write with No Hold Followed by Read with No Setup
MCK
A[25:2]
NBS0, NBS1,
NBS2, NBS3,
A0, A1
NWE
NRD
no hold
no setup
D[31:0]
write cycle
Early Read
wait state
read cycle
Figure 21-18. Early Read Wait State: NCS Controlled Write with No Hold Followed by a Read with No NCS Setup
MCK
A[25:2]
NBS0, NBS1,
NBS2, NBS3,
A0,A1
NCS
NRD
no hold
no setup
D[31:0]
write cycle
(WRITE_MODE = 0)
Early Read
wait state
read cycle
(READ_MODE = 0 or READ_MODE = 1)
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Figure 21-19. Early Read Wait State: NWE-controlled Write with No Hold Followed by a Read with One Set-up Cycle
MCK
A[25:2]
NBS0, NBS1,
NBS2, NBS3,
A0, A1
internal write controlling signal
external write controlling signal
(NWE)
no hold
read setup = 1
NRD
D[31:0]
write cycle
(WRITE_MODE = 1)
21.9.3
Early Read
wait state
read cycle
(READ_MODE = 0 or READ_MODE = 1)
Reload User Configuration Wait State
The user may change any of the configuration parameters by writing the SMC user interface.
When detecting that a new user configuration has been written in the user interface, the SMC
inserts a wait state before starting the next access. The so called “Reload User Configuration
Wait State” is used by the SMC to load the new set of parameters to apply to next accesses.
The Reload Configuration Wait State is not applied in addition to the Chip Select Wait State. If
accesses before and after re-programming the user interface are made to different devices
(Chip Selects), then one single Chip Select Wait State is applied.
On the other hand, if accesses before and after writing the user interface are made to the same
device, a Reload Configuration Wait State is inserted, even if the change does not concern the
current Chip Select.
21.9.3.1
User Procedure
To insert a Reload Configuration Wait State, the SMC detects a write access to any
SMC_MODE register of the user interface. If the user only modifies timing registers
(SMC_SETUP, SMC_PULSE, SMC_CYCLE registers) in the user interface, he must validate
the modification by writing the SMC_MODE, even if no change was made on the mode
parameters.
21.9.3.2
Slow Clock Mode Transition
A Reload Configuration Wait State is also inserted when the Slow Clock Mode is entered or
exited, after the end of the current transfer (see “Slow Clock Mode” on page 212).
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21.9.4
Read to Write Wait State
Due to an internal mechanism, a wait cycle is always inserted between consecutive read and
write SMC accesses.
This wait cycle is referred to as a read to write wait state in this document.
This wait cycle is applied in addition to chip select and reload user configuration wait states
when they are to be inserted. See Figure 21-16 on page 198.
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21.10 Data Float Wait States
Some memory devices are slow to release the external bus. For such devices, it is necessary to
add wait states (data float wait states) after a read access:
• before starting a read access to a different external memory
• before starting a write access to the same device or to a different external one.
The Data Float Output Time (t DF ) for each external memory device is programmed in the
TDF_CYCLES field of the SMC_MODE register for the corresponding chip select. The value of
TDF_CYCLES indicates the number of data float wait cycles (between 0 and 15) before the
external device releases the bus, and represents the time allowed for the data output to go to
high impedance after the memory is disabled.
Data float wait states do not delay internal memory accesses. Hence, a single access to an
external memory with long t DF will not slow down the execution of a program from internal
memory.
The data float wait states management depends on the READ_MODE and the TDF_MODE
fields of the SMC_MODE register for the corresponding chip select.
21.10.1
READ_MODE
Setting the READ_MODE to 1 indicates to the SMC that the NRD signal is responsible for turning off the tri-state buffers of the external memory device. The Data Float Period then begins
after the rising edge of the NRD signal and lasts TDF_CYCLES MCK cycles.
When the read operation is controlled by the NCS signal (READ_MODE = 0), the TDF field gives
the number of MCK cycles during which the data bus remains busy after the rising edge of NCS.
Figure 21-20 illustrates the Data Float Period in NRD-controlled mode (READ_MODE =1),
assuming a data float period of 2 cycles (TDF_CYCLES = 2). Figure 21-21 shows the read operation when controlled by NCS (READ_MODE = 0) and the TDF_CYCLES parameter equals 3.
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Figure 21-20. TDF Period in NRD Controlled Read Access (TDF = 2)
MCK
A[25:2]
NBS0, NBS1,
NBS2, NBS3,
A0, A1
NRD
NCS
tpacc
D[31:0]
TDF = 2 clock cycles
NRD controlled read operation
Figure 21-21. TDF Period in NCS Controlled Read Operation (TDF = 3)
MCK
A[25:2]
NBS0, NBS1,
NBS2, NBS3,
A0,A1
NRD
NCS
tpacc
D[31:0]
TDF = 3 clock cycles
NCS controlled read operation
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21.10.2
TDF Optimization Enabled (TDF_MODE = 1)
When the TDF_MODE of the SMC_MODE register is set to 1 (TDF optimization is enabled), the
SMC takes advantage of the setup period of the next access to optimize the number of wait
states cycle to insert.
Figure 21-22 shows a read access controlled by NRD, followed by a write access controlled by
NWE, on Chip Select 0. Chip Select 0 has been programmed with:
NRD_HOLD = 4; READ_MODE = 1 (NRD controlled)
NWE_SETUP = 3; WRITE_MODE = 1 (NWE controlled)
TDF_CYCLES = 6; TDF_MODE = 1 (optimization enabled).
Figure 21-22. TDF Optimization: No TDF Wait States Inserted if the TDF Period is Over When the Next Access Begins
MCK
A[25:2]
NRD
NRD_HOLD= 4
NWE
NWE_SETUP= 3
NCS0
TDF_CYCLES = 6
D[31:0]
read access on NCS0 (NRD controlled)
21.10.3
Read to Write
Wait State
write access on NCS0 (NWE controlled)
TDF Optimization Disabled (TDF_MODE = 0)
When optimization is disabled, tdf wait states are inserted at the end of the read transfer, so that
the data float period is ended when the second access begins. If the hold period of the read1
controlling signal overlaps the data float period, no additional tdf wait states will be inserted.
Figure 21-23, Figure 21-24 and Figure 21-25 illustrate the cases:
• read access followed by a read access on another chip select,
• read access followed by a write access on another chip select,
• read access followed by a write access on the same chip select,
with no TDF optimization.
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Figure 21-23. TDF Optimization Disabled (TDF Mode = 0). TDF Wait States Between 2 Read Accesses on Different Chip
Selects
MCK
A[25:2]
NBS0, NBS1,
NBS2, NBS3,
A0, A1
read1 controlling signal
(NRD)
read1 hold = 1
read2 controlling signal
(NRD)
read2 setup = 1
TDF_CYCLES = 6
D[31:0]
5 TDF WAIT STATES
read 2 cycle
TDF_MODE = 0
(optimization disabled)
read1 cycle
TDF_CYCLES = 6
Chip Select Wait State
Figure 21-24. TDF Mode = 0: TDF Wait States Between a Read and a Write Access on Different Chip Selects
MCK
A[25:2]
NBS0, NBS1,
NBS2, NBS3,
A0, A1
read1 controlling signal
(NRD)
read1 hold = 1
write2 controlling signal
(NWE)
write2 setup = 1
TDF_CYCLES = 4
D[31:0]
2 TDF WAIT STATES
read1 cycle
TDF_CYCLES = 4
Read to Write Chip Select
Wait State Wait State
write2 cycle
TDF_MODE = 0
(optimization disabled)
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Figure 21-25. TDF Mode = 0: TDF Wait States Between Read and Write Accesses on the Same Chip Select
MCK
A[25:2]
NBS0, NBS1,
NBS2, NBS3,
A0, A1
read1 controlling signal
(NRD)
write2 setup = 1
read1 hold = 1
write2 controlling signal
(NWE)
TDF_CYCLES = 5
D[31:0]
4 TDF WAIT STATES
read1 cycle
TDF_CYCLES = 5
Read to Write
Wait State
write2 cycle
TDF_MODE = 0
(optimization disabled)
21.11 External Wait
Any access can be extended by an external device using the NWAIT input signal of the SMC.
The EXNW_MODE field of the SMC_MODE register on the corresponding chip select must be
set to either to “10” (frozen mode) or “11” (ready mode). When the EXNW_MODE is set to “00”
(disabled), the NWAIT signal is simply ignored on the corresponding chip select. The NWAIT
signal delays the read or write operation in regards to the read or write controlling signal,
depending on the read and write modes of the corresponding chip select.
21.11.1
Restriction
When one of the EXNW_MODE is enabled, it is mandatory to program at least one hold
cycle for the read/write controlling signal. For that reason, the NWAIT signal cannot be
used in Page Mode (“Asynchronous Page Mode” on page 215), or in Slow Clock Mode
(“Slow Clock Mode” on page 212).
The NWAIT signal is assumed to be a response of the external device to the read/write request
of the SMC. Then NWAIT is examined by the SMC only in the pulse state of the read or write
controlling signal. The assertion of the NWAIT signal outside the expected period has no impact
on SMC behavior.
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21.11.2
Frozen Mode
When the external device asserts the NWAIT signal (active low), and after internal synchronization of this signal, the SMC state is frozen, i.e., SMC internal counters are frozen, and all control
signals remain unchanged. When the resynchronized NWAIT signal is deasserted, the SMC
completes the access, resuming the access from the point where it was stopped. See Figure 2126. This mode must be selected when the external device uses the NWAIT signal to delay the
access and to freeze the SMC.
The assertion of the NWAIT signal outside the expected period is ignored as illustrated in Figure
21-27.
Figure 21-26. Write Access with NWAIT Assertion in Frozen Mode (EXNW_MODE = 10)
MCK
A[25:2]
NBS0, NBS1,
NBS2, NBS3,
A0,A1
FROZEN STATE
4
3
2
1
1
1
1
0
3
2
2
2
2
1
NWE
6
5
4
0
NCS
D[31:0]
NWAIT
internally synchronized
NWAIT signal
Write cycle
EXNW_MODE = 10 (Frozen)
WRITE_MODE = 1 (NWE_controlled)
NWE_PULSE = 5
NCS_WR_PULSE = 7
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Figure 21-27. Read Access with NWAIT Assertion in Frozen Mode (EXNW_MODE = 10)
MCK
A[25:2]
NBS0, NBS1,
NBS2, NBS3,
A0,A1
NCS
FROZEN STATE
4
1
NRD
3
2
2
2
1
0
2
1
0
2
1
0
0
5
5
5
4
3
NWAIT
internally synchronized
NWAIT signal
Read cycle
EXNW_MODE = 10 (Frozen)
READ_MODE = 0 (NCS_controlled)
NRD_PULSE = 2, NRD_HOLD = 6
NCS_RD_PULSE =5, NCS_RD_HOLD =3
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21.11.3
Ready Mode
In Ready mode (EXNW_MODE = 11), the SMC behaves differently. Normally, the SMC begins
the access by down counting the setup and pulse counters of the read/write controlling signal. In
the last cycle of the pulse phase, the resynchronized NWAIT signal is examined.
If asserted, the SMC suspends the access as shown in Figure 21-28 and Figure 21-29. After
deassertion, the access is completed: the hold step of the access is performed.
This mode must be selected when the external device uses deassertion of the NWAIT signal to
indicate its ability to complete the read or write operation.
If the NWAIT signal is deasserted before the end of the pulse, or asserted after the end of the
pulse of the controlling read/write signal, it has no impact on the access length as shown in Figure 21-29.
Figure 21-28. NWAIT Assertion in Write Access: Ready Mode (EXNW_MODE = 11)
MCK
A[25:2]
NBS0, NBS1,
NBS2, NBS3,
A0,A1
Wait STATE
4
3
2
1
0
0
0
3
2
1
1
1
NWE
6
5
4
0
NCS
D[31:0]
NWAIT
internally synchronized
NWAIT signal
Write cycle
EXNW_MODE = 11 (Ready mode)
WRITE_MODE = 1 (NWE_controlled)
NWE_PULSE = 5
NCS_WR_PULSE = 7
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Figure 21-29. NWAIT Assertion in Read Access: Ready Mode (EXNW_MODE = 11)
MCK
A[25:2]
NBS0, NBS1,
NBS2, NBS3,
A0,A1
Wait STATE
6
5
4
3
2
1
0
0
6
5
4
3
2
1
1
NCS
NRD
0
NWAIT
internally synchronized
NWAIT signal
Read cycle
EXNW_MODE = 11(Ready mode)
READ_MODE = 0 (NCS_controlled)
Assertion is ignored
Assertion is ignored
NRD_PULSE = 7
NCS_RD_PULSE =7
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21.11.4
NWAIT Latency and Read/write Timings
There may be a latency between the assertion of the read/write controlling signal and the assertion of the NWAIT signal by the device. The programmed pulse length of the read/write
controlling signal must be at least equal to this latency plus the 2 cycles of resynchronization + 1
cycle. Otherwise, the SMC may enter the hold state of the access without detecting the NWAIT
signal assertion. This is true in frozen mode as well as in ready mode. This is illustrated on Figure 21-30.
When EXNW_MODE is enabled (ready or frozen), the user must program a pulse length of the
read and write controlling signal of at least:
minimal pulse length = NWAIT latency + 2 resynchronization cycles + 1 cycle
Figure 21-30. NWAIT Latency
MCK
A[25:2]
NBS0, NBS1,
NBS2, NBS3,
A0,A1
WAIT STATE
4
3
2
1
0
0
0
NRD
minimal pulse length
NWAIT
intenally synchronized
NWAIT signal
NWAIT latency 2 cycle resynchronization
Read cycle
EXNW_MODE = 10 or 11
READ_MODE = 1 (NRD_controlled)
NRD_PULSE = 5
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21.12 Slow Clock Mode
The SMC is able to automatically apply a set of “slow clock mode” read/write waveforms when
an internal signal driven by the Power Management Controller is asserted because MCK has
been turned to a very slow clock rate (typically 32kHz clock rate). In this mode, the user-programmed waveforms are ignored and the slow clock mode waveforms are applied. This mode is
provided so as to avoid reprogramming the User Interface with appropriate waveforms at very
slow clock rate. When activated, the slow mode is active on all chip selects.
21.12.1
Slow Clock Mode Waveforms
Figure 21-31 illustrates the read and write operations in slow clock mode. They are valid on all
chip selects. Table 21-6 indicates the value of read and write parameters in slow clock mode.
Figure 21-31. Read/write Cycles in Slow Clock Mode
MCK
MCK
A[25:2]
A[25:2]
NBS0, NBS1,
NBS2, NBS3,
A0,A1
NBS0, NBS1,
NBS2, NBS3,
A0,A1
NWE
NRD
1
1
1
1
1
NCS
NCS
NRD_CYCLE = 2
NWE_CYCLE = 3
SLOW CLOCK MODE WRITE
Table 21-6.
Read and Write Timing Parameters in Slow Clock Mode
Read Parameters
212
SLOW CLOCK MODE READ
Duration (cycles)
Write Parameters
Duration (cycles)
NRD_SETUP
1
NWE_SETUP
1
NRD_PULSE
1
NWE_PULSE
1
NCS_RD_SETUP
0
NCS_WR_SETUP
0
NCS_RD_PULSE
2
NCS_WR_PULSE
3
NRD_CYCLE
2
NWE_CYCLE
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21.12.2
Switching from (to) Slow Clock Mode to (from) Normal Mode
When switching from slow clock mode to the normal mode, the current slow clock mode transfer
is completed at high clock rate, with the set of slow clock mode parameters.See Figure 21-32 on
page 213. The external device may not be fast enough to support such timings.
Figure 21-33 illustrates the recommended procedure to properly switch from one mode to the
other.
Figure 21-32. Clock Rate Transition Occurs while the SMC is Performing a Write Operation
Slow Clock Mode
internal signal from PMC
MCK
A[25:2]
NBS0, NBS1,
NBS2, NBS3,
A0,A1
NWE
1
1
1
1
1
1
2
3
2
NCS
NWE_CYCLE = 3
NWE_CYCLE = 7
SLOW CLOCK MODE WRITE SLOW CLOCK MODE WRITE
This write cycle finishes with the slow clock mode set
of parameters after the clock rate transition
NORMAL MODE WRITE
Slow clock mode transition is detected:
Reload Configuration Wait State
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Figure 21-33. Recommended Procedure to Switch from Slow Clock Mode to Normal Mode or from Normal Mode to Slow
Clock Mode
Slow Clock Mode
internal signal from PMC
MCK
A[25:2]
NBS0, NBS1,
NBS2, NBS3,
A0,A1
NWE
1
1
1
2
3
2
NCS
SLOW CLOCK MODE WRITE
IDLE STATE
NORMAL MODE WRITE
Reload Configuration
Wait State
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21.13 Asynchronous Page Mode
The SMC supports asynchronous burst reads in page mode, providing that the page mode is
enabled in the SMC_MODE register (PMEN field). The page size must be configured in the
SMC_MODE register (PS field) to 4, 8, 16 or 32 bytes.
The page defines a set of consecutive bytes into memory. A 4-byte page (resp. 8-, 16-, 32-byte
page) is always aligned to 4-byte boundaries (resp. 8-, 16-, 32-byte boundaries) of memory. The
MSB of data address defines the address of the page in memory, the LSB of address define the
address of the data in the page as detailed in Table 21-7.
With page mode memory devices, the first access to one page (tpa) takes longer than the subsequent accesses to the page (tsa ) as shown in Figure 21-34. When in page mode, the SMC
enables the user to define different read timings for the first access within one page, and next
accesses within the page.
Table 21-7.
Page Size
Page Address(1)
Data Address in the Page(2)
4 bytes
A[25:2]
A[1:0]
8 bytes
A[25:3]
A[2:0]
16 bytes
A[25:4]
A[3:0]
32 bytes
A[25:5]
A[4:0]
Notes:
21.13.1
Page Address and Data Address within a Page
1. A denotes the address bus of the memory device.
2. For 16-bit devices, the bit 0 of address is ignored. For 32-bit devices, bits [1:0] are ignored.
Protocol and Timings in Page Mode
Figure 21-34 shows the NRD and NCS timings in page mode access.
Figure 21-34. Page Mode Read Protocol (Address MSB and LSB are defined in Table 21-7)
MCK
A[MSB]
A[LSB]
NRD
NCS
tpa
tsa
tsa
D[31:0]
NCS_RD_PULSE
NRD_PULSE
NRD_PULSE
The NRD and NCS signals are held low during all read transfers, whatever the programmed values of the setup and hold timings in the User Interface may be. Moreover, the NRD and NCS
timings are identical. The pulse length of the first access to the page is defined with the
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NCS_RD_PULSE field of the SMC_PULSE register. The pulse length of subsequent accesses
within the page are defined using the NRD_PULSE parameter.
In page mode, the programming of the read timings is described in Table 21-8:
Table 21-8.
Programming of Read Timings in Page Mode
Parameter
Value
Definition
READ_MODE
‘x’
No impact
NCS_RD_SETUP
‘x’
No impact
NCS_RD_PULSE
tpa
Access time of first access to the page
NRD_SETUP
‘x’
No impact
NRD_PULSE
tsa
Access time of subsequent accesses in the page
NRD_CYCLE
‘x’
No impact
The SMC does not check the coherency of timings. It will always apply the NCS_RD_PULSE
timings as page access timing (tpa) and the NRD_PULSE for accesses to the page (tsa), even if
the programmed value for tpa is shorter than the programmed value for tsa.
21.13.2
Byte Access Type in Page Mode
The Byte Access Type configuration remains active in page mode. For 16-bit or 32-bit page
mode devices that require byte selection signals, configure the BAT field of the
SMC_REGISTER to 0 (byte select access type).
21.13.3
Page Mode Restriction
The page mode is not compatible with the use of the NWAIT signal. Using the page mode and
the NWAIT signal may lead to unpredictable behavior.
21.13.4
Sequential and Non-sequential Accesses
If the chip select and the MSB of addresses as defined in Table 21-7 are identical, then the current access lies in the same page as the previous one, and no page break occurs.
Using this information, all data within the same page, sequential or not sequential, are accessed
with a minimum access time (tsa). Figure 21-35 illustrates access to an 8-bit memory device in
page mode, with 8-byte pages. Access to D1 causes a page access with a long access time
(tpa). Accesses to D3 and D7, though they are not sequential accesses, only require a short
access time (tsa).
If the MSB of addresses are different, the SMC performs the access of a new page. In the same
way, if the chip select is different from the previous access, a page break occurs. If two sequential accesses are made to the page mode memory, but separated by an other internal or external
peripheral access, a page break occurs on the second access because the chip select of the
device was deasserted between both accesses.
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Figure 21-35. Access to Non-sequential Data within the Same Page
MCK
Page address
A[25:3]
A[2], A1, A0
A1
A3
A7
NRD
NCS
D[7:0]
D1
NCS_RD_PULSE
D3
NRD_PULSE
D7
NRD_PULSE
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21.14 Static Memory Controller (SMC) User Interface
The SMC is programmed using the registers listed in Table 21-9. For each chip select, a set of 4 registers is used to program the parameters of the external device connected on it. In Table 21-9, “CS_number” denotes the chip select number.
16 bytes (0x10) are required per chip select.
The user must complete writing the configuration by writing any one of the SMC_MODE registers.
Table 21-9.
SMC Register Mapping
Offset
Register
Name
Access
Reset State
0x10 x CS_number + 0x00
SMC Setup Register
SMC_SETUP
Read/Write
0x01010101
0x10 x CS_number + 0x04
SMC Pulse Register
SMC_PULSE
Read/Write
0x01010101
0x10 x CS_number + 0x08
SMC Cycle Register
SMC_CYCLE
Read/Write
0x00030003
0x10 x CS_number + 0x0C
SMC Mode Register
SMC_MODE
Read/Write
0x10001000
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21.14.1 SMC Setup Register
Register Name:
SMC_SETUP[0 ..7]
Access Type:
Read/Write
31
30
–
–
23
22
–
–
15
14
–
–
7
6
–
–
29
28
27
26
25
24
18
17
16
10
9
8
1
0
NCS_RD_SETUP
21
20
19
NRD_SETUP
13
12
11
NCS_WR_SETUP
5
4
3
2
NWE_SETUP
• NWE_SETUP: NWE Setup Length
The NWE signal setup length is defined as:
NWE setup length = (128* NWE_SETUP[5] + NWE_SETUP[4:0]) clock cycles
• NCS_WR_SETUP: NCS Setup Length in WRITE Access
In write access, the NCS signal setup length is defined as:
NCS setup length = (128* NCS_WR_SETUP[5] + NCS_WR_SETUP[4:0]) clock cycles
• NRD_SETUP: NRD Setup Length
The NRD signal setup length is defined in clock cycles as:
NRD setup length = (128* NRD_SETUP[5] + NRD_SETUP[4:0]) clock cycles
• NCS_RD_SETUP: NCS Setup Length in READ Access
In read access, the NCS signal setup length is defined as:
NCS setup length = (128* NCS_RD_SETUP[5] + NCS_RD_SETUP[4:0]) clock cycles
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21.14.2 SMC Pulse Register
Register Name:
SMC_PULSE[0..7]
Access Type:
31
Read/Write
30
29
28
–
23
22
21
20
–
15
26
25
24
19
18
17
16
10
9
8
2
1
0
NRD_PULSE
14
13
12
–
7
27
NCS_RD_PULSE
11
NCS_WR_PULSE
6
5
4
–
3
NWE_PULSE
• NWE_PULSE: NWE Pulse Length
The NWE signal pulse length is defined as:
NWE pulse length = (256* NWE_PULSE[6] + NWE_PULSE[5:0]) clock cycles
The NWE pulse length must be at least 1 clock cycle.
• NCS_WR_PULSE: NCS Pulse Length in WRITE Access
In write access, the NCS signal pulse length is defined as:
NCS pulse length = (256* NCS_WR_PULSE[6] + NCS_WR_PULSE[5:0]) clock cycles
The NCS pulse length must be at least 1 clock cycle.
• NRD_PULSE: NRD Pulse Length
In standard read access, the NRD signal pulse length is defined in clock cycles as:
NRD pulse length = (256* NRD_PULSE[6] + NRD_PULSE[5:0]) clock cycles
The NRD pulse length must be at least 1 clock cycle.
In page mode read access, the NRD_PULSE parameter defines the duration of the subsequent accesses in the page.
• NCS_RD_PULSE: NCS Pulse Length in READ Access
In standard read access, the NCS signal pulse length is defined as:
NCS pulse length = (256* NCS_RD_PULSE[6] + NCS_RD_PULSE[5:0]) clock cycles
The NCS pulse length must be at least 1 clock cycle.
In page mode read access, the NCS_RD_PULSE parameter defines the duration of the first access to one page.
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21.14.3 SMC Cycle Register
Register Name:
SMC_CYCLE[0..7]
Access Type:
Read/Write
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
NRD_CYCLE
23
22
21
20
19
18
17
16
NRD_CYCLE
15
14
13
12
11
10
9
8
–
–
–
–
–
–
–
NWE_CYCLE
7
6
5
4
3
2
1
0
NWE_CYCLE
• NWE_CYCLE: Total Write Cycle Length
The total write cycle length is the total duration in clock cycles of the write cycle. It is equal to the sum of the setup, pulse
and hold steps of the NWE and NCS signals. It is defined as:
Write cycle length = (NWE_CYCLE[8:7]*256 + NWE_CYCLE[6:0]) clock cycles
• NRD_CYCLE: Total Read Cycle Length
The total read cycle length is the total duration in clock cycles of the read cycle. It is equal to the sum of the setup, pulse
and hold steps of the NRD and NCS signals. It is defined as:
Read cycle length = (NRD_CYCLE[8:7]*256 + NRD_CYCLE[6:0]) clock cycles
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21.14.4 SMC MODE Register
Register Name:
SMC_MODE[0..7]
Access Type:
Read/Write
31
30
–
–
29
28
23
22
21
20
–
–
–
TDF_MODE
15
14
13
–
–
7
6
–
–
PS
12
DBW
5
4
EXNW_MODE
27
26
25
24
–
–
–
PMEN
19
18
17
16
TDF_CYCLES
11
10
9
8
–
–
–
BAT
3
2
1
0
–
–
WRITE_MODE
READ_MODE
• READ_MODE:
1: The read operation is controlled by the NRD signal.
– If TDF cycles are programmed, the external bus is marked busy after the rising edge of NRD.
– If TDF optimization is enabled (TDF_MODE =1), TDF wait states are inserted after the setup of NRD.
0: The read operation is controlled by the NCS signal.
– If TDF cycles are programmed, the external bus is marked busy after the rising edge of NCS.
– If TDF optimization is enabled (TDF_MODE =1), TDF wait states are inserted after the setup of NCS.
• WRITE_MODE
1: The write operation is controlled by the NWE signal.
– If TDF optimization is enabled (TDF_MODE =1), TDF wait states will be inserted after the setup of NWE.
0: The write operation is controlled by the NCS signal.
– If TDF optimization is enabled (TDF_MODE =1), TDF wait states will be inserted after the setup of NCS.
• EXNW_MODE: NWAIT Mode
The NWAIT signal is used to extend the current read or write signal. It is only taken into account during the pulse phase of
the read and write controlling signal. When the use of NWAIT is enabled, at least one cycle hold duration must be programmed for the read and write controlling signal.
EXNW_MODE
NWAIT Mode
0
0
Disabled
0
1
Reserved
1
0
Frozen Mode
1
1
Ready Mode
• Disabled Mode: The NWAIT input signal is ignored on the corresponding Chip Select.
• Frozen Mode: If asserted, the NWAIT signal freezes the current read or write cycle. After deassertion, the read/write
cycle is resumed from the point where it was stopped.
• Ready Mode: The NWAIT signal indicates the availability of the external device at the end of the pulse of the controlling
read or write signal, to complete the access. If high, the access normally completes. If low, the access is extended until
NWAIT returns high.
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• BAT: Byte Access Type
This field is used only if DBW defines a 16- or 32-bit data bus.
• 1: Byte write access type:
– Write operation is controlled using NCS, NWR0, NWR1, NWR2, NWR3.
– Read operation is controlled using NCS and NRD.
• 0: Byte select access type:
– Write operation is controlled using NCS, NWE, NBS0, NBS1, NBS2 and NBS3
– Read operation is controlled using NCS, NRD, NBS0, NBS1, NBS2 and NBS3
• DBW: Data Bus Width
DBW
Data Bus Width
0
0
8-bit bus
0
1
16-bit bus
1
0
32-bit bus
1
1
Reserved
• TDF_CYCLES: Data Float Time
This field gives the integer number of clock cycles required by the external device to release the data after the rising edge
of the read controlling signal. The SMC always provide one full cycle of bus turnaround after the TDF_CYCLES period. The
external bus cannot be used by another chip select during TDF_CYCLES + 1 cycles. From 0 up to 15 TDF_CYCLES can
be set.
• TDF_MODE: TDF Optimization
1: TDF optimization is enabled.
– The number of TDF wait states is optimized using the setup period of the next read/write access.
0: TDF optimization is disabled.
– The number of TDF wait states is inserted before the next access begins.
• PMEN: Page Mode Enabled
1: Asynchronous burst read in page mode is applied on the corresponding chip select.
0: Standard read is applied.
• PS: Page Size
If page mode is enabled, this field indicates the size of the page in bytes.
PS
Page Size
0
0
4-byte page
0
1
8-byte page
1
0
16-byte page
1
1
32-byte page
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22. SDRAM Controller (SDRAMC)
22.1
Description
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 keeps track of the
active row in each bank, thus maximizing SDRAM performance, e.g., the application may be
placed in one bank and data in the other banks. So as to optimize performance, it is advisable to
avoid accessing different rows in the same bank.
The SDRAM controller supports a CAS latency of 1, 2 or 3 and optimizes the read access
depending on the frequency.
The different modes available - self-refresh, power-down and deep power-down modes - minimize power consumption on the SDRAM device.
22.2
I/O Lines Description
Table 22-1.
I/O Line Description
Name
Description
Type
Active Level
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
Low
CAS
Column Signal
Output
Low
SDWE
SDRAM Write Enable
Output
Low
NBS[3:0]
Data Mask Enable Signals
Output
Low
SDRAMC_A[12:0]
Address Bus
Output
D[31:0]
Data Bus
I/O
225
6249B–ATARM–14-Dec-06
22.3
Application Example
22.3.1
Software Interface
The SDRAM address space is organized into banks, rows, and columns. The SDRAM controller
allows mapping different memory types according to the values set in the SDRAMC configuration register.
The SDRAM Controller’s function is to make the SDRAM device access protocol transparent to
the user. Table 22-2 to Table 22-7 illustrate the SDRAM device memory mapping seen by the
user in correlation with the device structure. Various configurations are illustrated.
22.3.2
32-bit Memory Data Bus Width
Table 22-2.
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]
14
13
12
11
10
9
8
7
Row[10:0]
Bk[1:0]
Bk[1:0]
6
5
4
3
2
Column[7:0]
Row[10:0]
0
M[1:0]
Column[9:0]
Row[10:0]
1
M[1:0]
Column[8:0]
Row[10:0]
Bk[1:0]
Table 22-3.
15
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 22-4.
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:
226
15
14
Row[12:0]
Bk[1:0]
Bk[1:0]
16
Row[12:0]
Row[12:0]
Row[12:0]
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.
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
22.3.3
16-bit Memory Data Bus Width
Table 22-5.
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
M0
M0
Column[9:0]
Row[10:0]
0
M0
Column[8:0]
Row[10:0]
Bk[1:0]
5
Column[7:0]
Row[10:0]
Bk[1:0]
Table 22-6.
14
M0
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
M0
M0
Column[9:0]
Row[11:0]
0
M0
Column[8:0]
Row[11:0]
Bk[1:0]
5
Column[7:0]
Row[11:0]
Bk[1:0]
Table 22-7.
15
M0
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
Column[7:0]
Column[8:0]
Column[9:0]
Column[10:0]
3
2
1
0
M0
M0
M0
M0
1. M0 is the byte address inside a 16-bit half-word.
2. Bk[1] = BA1, Bk[0] = BA0.
227
6249B–ATARM–14-Dec-06
22.4
22.4.1
Product Dependencies
SDRAM Device Initialization
The initialization sequence is generated by software. The SDRAM devices are initialized by the
following sequence:
1. SDRAM features must be set in the configuration register: asynchronous timings (TRC,
TRAS, etc.), number of columns, rows, CAS latency, and the data bus width.
2. For mobile SDRAM, temperature-compensated self refresh (TCSR), drive strength
(DS) and partial array self refresh (PASR) must be set in the Low Power Register.
3. The SDRAM memory type must be set in the Memory Device Register.
4. A minimum pause of 200 µs is provided to precede any signal toggle.
5.
(1)
A NOP command is issued to the SDRAM devices. The application must set Mode to
1 in the Mode Register and perform a write access to any SDRAM address.
6. An All Banks Precharge command is issued to the SDRAM devices. The application
must set Mode to 2 in the Mode Register and perform a write access to any SDRAM
address.
7. Eight auto-refresh (CBR) cycles are provided. The application must set the Mode to 4 in
the Mode Register and perform a write access to any SDRAM location eight times.
8. A Mode Register set (MRS) cycle is issued to program the parameters of the SDRAM
devices, in particular CAS latency and burst length. The application must set Mode to 3
in the Mode Register and perform a write access to the SDRAM. The write address
must be chosen so that BA[1:0] are set to 0. For example, with a 16-bit 128 MB SDRAM
(12 rows, 9 columns, 4 banks) bank address, the SDRAM write access should be done
at the address 0x20000000.
9. For mobile SDRAM initialization, an Extended Mode Register set (EMRS) cycle is
issued to program the SDRAM parameters (TCSR, PASR, DS). The application must
set Mode to 5 in the Mode Register and perform a write access to the SDRAM. The
write address must be chosen so that BA[1] or BA[0] are set to 1. For example, with a
16-bit 128 MB SDRAM, (12 rows, 9 columns, 4 banks) bank address the SDRAM write
access should be done at the address 0x20800000 or 0x20400000.
10. The application must go into Normal Mode, setting Mode to 0 in the Mode Register and
performing a write access at any location in the SDRAM.
11. Write the refresh rate into the count field in the SDRAMC Refresh Timer register.
(Refresh rate = delay between refresh cycles). The SDRAM device requires a refresh
every 15.625 µs or 7.81 µs. With a 100 MHz frequency, the Refresh Timer Counter
Register must be set with the value 1562(15.652 µs x 100 MHz) or 781(7.81 µs x 100
MHz).
After initialization, the SDRAM devices are fully functional.
Note:
228
1. It is strongly recommended to respect the instructions stated in Step 5 of the initialization process in order to be certain that the subsequent commands issued by the SDRAMC will be
taken into account.
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Figure 22-1. SDRAM Device Initialization Sequence
SDCKE
tRP
tRC
tMRD
SDCK
SDRAMC_A[9:0]
A10
SDRAMC_A[12:11]
SDCS
RAS
CAS
SDWE
NBS
Inputs Stable for
200 µsec
22.4.2
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.
22.4.3
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.
229
6249B–ATARM–14-Dec-06
22.5
22.5.1
Functional Description
SDRAM Controller Write Cycle
The SDRAM Controller allows burst access or single access. In both cases, the SDRAM controller keeps track of the active row in each bank, thus maximizing performance. 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 (tRP) commands and
active/write (tRCD) commands. For definition of these timing parameters, refer to the “SDRAMC
Configuration Register” on page 241. This is described in Figure 22-2 below.
Figure 22-2. Write Burst, 32-bit SDRAM Access
tRCD = 3
SDCS
SDCK
SDRAMC_A[12:0]
Row n
col a
col b
col c
col d
col e
col f
col g
col h
col i
col j
col k
col l
Dnb
Dnc
Dnd
Dne
Dnf
Dng
Dnh
Dni
Dnj
Dnk
Dnl
RAS
CAS
SDWE
D[31:0]
230
Dna
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AT91SAM9263 Preliminary
22.5.2
SDRAM Controller Read Cycle
The SDRAM Controller allows burst access, incremental burst of unspecified length or single
access. In all cases, the SDRAM Controller keeps track of the active row in each bank, thus
maximizing performance of the SDRAM. If row and bank addresses do not match the previous
row/bank address, then the SDRAM controller automatically generates a precharge command,
activates the new row and starts the read command. To comply with the SDRAM timing parameters, additional clock cycles on SDCK are inserted between precharge and active commands
(tRP) and between active and read command (tRCD). These two parameters are set in the configuration register of the SDRAM Controller. After a read command, additional wait states are
generated to comply with the CAS latency (1, 2 or 3 clock delays specified in the configuration
register).
For a single access or an incremented burst of unspecified length, the SDRAM Controller anticipates the next access. While the last value of the column is returned by the SDRAM Controller
on the bus, the SDRAM Controller anticipates the read to the next column and thus anticipates
the CAS latency. This reduces the effect of the CAS latency on the internal bus.
For burst access of specified length (4, 8, 16 words), access is not anticipated. This case leads
to the best performance. If the burst is broken (border, busy mode, etc.), the next access is handled as an incrementing burst of unspecified length.
Figure 22-3. Read Burst, 32-bit SDRAM Access
tRCD = 3
CAS = 2
SDCS
SDCK
SDRAMC_A[12:0]
Row n
col a
col b
col c
col d
col e
col f
RAS
CAS
SDWE
D[31:0]
(Input)
Dna
Dnb
Dnc
Dnd
Dne
Dnf
231
6249B–ATARM–14-Dec-06
22.5.3
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 22-4 below.
Figure 22-4. Read Burst with Boundary Row Access
TRP = 3
TRCD = 3
CAS = 2
SDCS
SDCK
Row n
SDRAMC_A[12:0]
col a
col b
col c
col d
Row m
col a
col b
col c
col d
col e
RAS
CAS
SDWE
D[31:0]
232
Dna
Dnb
Dnc
Dnd
Dma
Dmb
Dmc
Dmd
Dme
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
22.5.4
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. An internal 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 is 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 indicates that the
device is busy and the master is held by a wait signal. See Figure 22-5.
Figure 22-5. Refresh Cycle Followed by a Read Access
tRP = 3
tRC = 8
tRCD = 3
CAS = 2
SDCS
SDCK
Row n
SDRAMC_A[12:0]
Row m
col c col d
col a
RAS
CAS
SDWE
D[31:0]
(input)
Dnb
Dnc
Dnd
Dma
233
6249B–ATARM–14-Dec-06
22.5.5
Power Management
Three low-power modes are available:
• Self-refresh Mode: The SDRAM executes its own Auto-refresh cycle without control of the
SDRAM Controller. Current drained by the SDRAM is very low.
• Power-down Mode: Auto-refresh cycles are controlled by the SDRAM Controller. Between
auto-refresh cycles, the SDRAM is in power-down. Current drained in Power-down mode is
higher than in Self-refresh Mode.
• Deep Power-down Mode: (Only available with Mobile SDRAM) The SDRAM contents are
lost, but the SDRAM does not drain any current.
The SDRAM Controller activates one low-power mode as soon as the SDRAM device is not
selected. It is possible to delay the entry in self-refresh and power-down mode after the last
access by programming a timeout value in the Low Power Register.
234
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AT91SAM9263 Preliminary
22.5.6
Self-refresh Mode
This mode is selected by programming the LPCB field to 1 in the SDRAMC Low Power Register.
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.
Some low-power SDRAMs (e.g., mobile SDRAM) can refresh only one quarter or a half quarter
or all banks of the SDRAM array. This feature reduces the self-refresh current. To configure this
feature, Temperature Compensated Self Refresh (TCSR), Partial Array Self Refresh (PASR)
and Drive Strength (DS) parameters must be set in the Low Power Register and transmitted to
the low-power SDRAM during initialization.
After initialization, as soon as PASR/DS/TCSR fields are modified and self-refresh mode is activated, the Extended Mode Register is accessed automatically and PASR/DS/TCSR bits are
updated before entry into self-refresh mode.
The SDRAM device must remain in self-refresh mode for a minimum period of tRAS and may
remain in self-refresh mode for an indefinite period. This is described in Figure 22-6.
Figure 22-6. Self-refresh Mode Behavior
Self Refresh Mode
TXSR = 3
SRCB = 1
Write
SDRAMC_SRR
Row
SDRAMC_A[12:0]
SDCK
SDCKE
SDCS
RAS
CAS
SDWE
Access Request
to the SDRAM Controller
235
6249B–ATARM–14-Dec-06
22.5.7
Low-power Mode
This mode is selected by programming the LPCB field to 2 in the SDRAMC Low Power Register.
Power consumption is greater than in self-refresh mode. All the input and output buffers of the
SDRAM device are deactivated except SDCKE, which remains low. In contrast to self-refresh
mode, the SDRAM device cannot remain in low-power mode longer than the refresh period (64
ms for a whole device refresh operation). As no auto-refresh operations are performed by the
SDRAM itself, the SDRAM Controller carries out the refresh operation. The exit procedure is
faster than in self-refresh mode.
This is described in Figure 22-7.
Figure 22-7. Low-power Mode Behavior
TRCD = 3
CAS = 2
Low Power Mode
SDCS
SDCK
SDRAMC_A[12:0]
Row n
col a
col b
col c
col d
col e
col f
RAS
CAS
SDCKE
D[31:0]
(input)
236
Dna
Dnb
Dnc
Dnd
Dne
Dnf
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
22.5.8
Deep Power-down Mode
This mode is selected by programming the LPCB field to 3 in the SDRAMC Low Power Register.
When this mode is activated, all internal voltage generators inside the SDRAM are stopped and
all data is lost.
When this mode is enabled, the application must not access to the SDRAM until a new initialization sequence is done (See “SDRAM Device Initialization” on page 228).
This is described in Figure 22-8.
Figure 22-8. Deep Power-down Mode Behavior
tRP = 3
SDCS
SDCK
Row n
SDRAMC_A[12:0]
col c
col d
RAS
CAS
SDWE
CKE
D[31:0]
(input)
Dnb
Dnc
Dnd
237
6249B–ATARM–14-Dec-06
22.6
SDRAM Controller User Interface
Table 22-8.
Offset
Register
Name
Access
Reset State
0x00
SDRAMC Mode Register
SDRAMC_MR
Read/Write
0x00000000
0x04
SDRAMC Refresh Timer Register
SDRAMC_TR
Read/Write
0x00000000
0x08
SDRAMC Configuration Register
SDRAMC_CR
Read/Write
0x852372C0
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
0x24
SDRAMC Memory Device Register
SDRAMC_MDR
Read
0x0
–
–
–
0x28 - 0xFC
238
SDRAM Controller Memory Map
Reserved
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
22.6.1
SDRAMC Mode Register
Register Name:
SDRAMC_MR
Access Type:
Read/Write
Reset Value:
0x00000000
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
–
14
–
13
–
12
–
11
–
10
–
9
–
8
–
7
–
6
–
5
–
4
–
3
–
2
1
0
MODE
• MODE: SDRAMC Command Mode
This field defines the command issued by the SDRAM Controller when the SDRAM device is accessed.
MODE
Description
0
0
0
Normal mode. Any access to the SDRAM is decoded normally.
0
0
1
The SDRAM Controller issues a NOP command when the SDRAM device is accessed regardless of the
cycle.
0
1
0
The SDRAM Controller issues an “All Banks Precharge” command when the SDRAM device is accessed
regardless of the cycle.
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.
1
0
0
The SDRAM Controller issues an “Auto-Refresh” Command when the SDRAM device is accessed
regardless of the cycle. Previously, an “All Banks Precharge” command must be issued.
1
0
1
The SDRAM Controller issues an extended 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 an “Extended Load Mode Register” command with the value
“offset” written to the SDRAM device Mode Register.
1
1
0
Deep power-down mode. Enters deep power-down mode.
239
6249B–ATARM–14-Dec-06
22.6.2
SDRAMC Refresh Timer Register
Register Name:
SDRAMC_TR
Access Type:
Read/Write
Reset Value:
0x00000000
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
–
14
–
13
–
12
–
11
10
9
8
7
6
5
4
1
0
COUNT
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, 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.
240
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AT91SAM9263 Preliminary
22.6.3
SDRAMC Configuration Register
Register Name:
SDRAMC_CR
Access Type:
Read/Write
Reset Value:
0x852372C0
31
30
29
28
27
26
TXSR
23
21
20
19
18
TRCD
17
16
9
8
TRP
14
13
12
11
10
TRC
7
DBW
24
TRAS
22
15
25
TWR
6
5
CAS
4
NB
3
2
NR
1
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
241
6249B–ATARM–14-Dec-06
• CAS: CAS Latency
Reset value is two cycles.
In the SDRAMC, only a CAS latency of one, two and three cycles are managed. In any case, another value must be
programmed.
CAS
CAS Latency (Cycles)
0
0
Reserved
0
1
1
1
0
2
1
1
3
• DBW: Data Bus Width
Reset value is 16 bits
0: Data bus width is 32 bits.
1: Data bus width is 16 bits.
• TWR: Write Recovery Delay
Reset value is two cycles.
This field defines the Write Recovery Time in number of cycles. Number of cycles is between 0 and 15.
• TRC: Row Cycle Delay
Reset value is seven cycles.
This field defines the delay between a Refresh and an Activate Command in number of cycles. Number of cycles is
between 0 and 15.
• TRP: Row Precharge Delay
Reset value is three cycles.
This field defines the delay between a Precharge Command and another Command in number of cycles. Number of cycles
is between 0 and 15.
• TRCD: Row to Column Delay
Reset value is two cycles.
This field defines the delay between an Activate Command and a Read/Write Command in number of cycles. Number of
cycles is between 0 and 15.
• TRAS: Active to Precharge Delay
Reset value is five cycles.
This field defines the delay between an Activate Command and a Precharge Command in number of cycles. Number of
cycles is between 0 and 15.
• TXSR: Exit Self Refresh to Active Delay
Reset value is eight cycles.
This field defines the delay between SCKE set high and an Activate Command in number of cycles. Number of cycles is
between 0 and 15.
242
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AT91SAM9263 Preliminary
243
6249B–ATARM–14-Dec-06
22.6.4
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
7
–
6
5
PASR
TIMEOUT
DS
4
3
–
8
TCSR
2
–
1
0
LPCB
• LPCB: Low-power Configuration Bits
00
Low Power Feature is inhibited: no Power-down, Self-refresh or Deep Power-down command is issued to the
SDRAM device.
01
The SDRAM Controller issues a Self-refresh command to the SDRAM device, the SDCLK clock is deactivated
and the SDCKE signal is set low. The SDRAM device leaves the Self Refresh Mode when accessed and enters
it after the access.
10
The SDRAM Controller issues a Power-down Command to the SDRAM device after each access, the SDCKE
signal is set to low. The SDRAM device leaves the Power-down Mode when accessed and enters it after the
access.
11
The SDRAM Controller issues a Deep Power-down command to the SDRAM device. This mode is unique to
low-power SDRAM.
• PASR: Partial Array Self-refresh (only for low-power SDRAM)
PASR parameter is transmitted to the SDRAM during initialization to specify whether only one quarter, one half or all banks
of the SDRAM array are enabled. Disabled banks are not refreshed in self-refresh mode. This parameter must be set
according to the SDRAM device specification.
After initialization, as soon as PASR field is modified and self-refresh mode is activated, the Extended Mode Register is
accessed automatically and PASR bits are updated before entry in self-refresh mode.
• TCSR: Temperature Compensated Self-Refresh (only for low-power SDRAM)
TCSR parameter is transmitted to the SDRAM during initialization to set the refresh interval during self-refresh mode
depending on the temperature of the low-power SDRAM. This parameter must be set according to the SDRAM device
specification.
After initialization, as soon as TCSR field is modified and self-refresh mode is activated, the Extended Mode Register is
accessed automatically and TCSR bits are updated before entry in self-refresh mode.
• DS: Drive Strength (only for low-power SDRAM)
DS parameter is transmitted to the SDRAM during initialization to select the SDRAM strength of data output. This parameter must be set according to the SDRAM device specification.
244
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
After initialization, as soon as DS field is modified and self-refresh mode is activated, the Extended Mode Register is
accessed automatically and DS bits are updated before entry in self-refresh mode.
• TIMEOUT: Time to define when low-power mode is enabled
00
The SDRAM controller activates the SDRAM low-power mode immediately after the end of the last transfer.
01
The SDRAM controller activates the SDRAM low-power mode 64 clock cycles after the end of the last transfer.
10
The SDRAM controller activates the SDRAM low-power mode 128 clock cycles after the end of the last
transfer.
11
Reserved.
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6249B–ATARM–14-Dec-06
22.6.5
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.
22.6.6
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.
246
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22.6.7
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.
22.6.8
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.
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6249B–ATARM–14-Dec-06
22.6.9
SDRAMC Memory Device Register
Register Name:
SDRAMC_MDR
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
MD
• MD: Memory Device Type
248
00
SDRAM
01
Low-power SDRAM
10
Reserved
11
Reserved.
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
23. Error Corrected Code (ECC) Controller
23.1
Description
NAND Flash/SmartMedia devices contain by default invalid blocks which have one or more
invalid bits. Over the NAND Flash/SmartMedia lifetime, additional invalid blocks may occur
which can be detected/corrected by ECC code.
The ECC Controller is a mechanism that encodes data in a manner that makes possible the
identification and correction of certain errors in data. The ECC controller is capable of single
bit error correction and 2-bit random detection. When NAND Flash/SmartMedia have more
than 2 bits of errors, the data cannot be corrected.
The ECC user interface is compliant with the ARM Advanced Peripheral Bus (APB rev2).
23.2
Block Diagram
Figure 23-1. Block Diagram
NAND Flash
Static
Memory
Controller
SmartMedia
Logic
ECC
Controller
Ctrl/ECC Algorithm
User Interface
APB
23.3
Functional Description
A page in NAND Flash and SmartMedia memories contains an area for main data and an
additional area used for redundancy (ECC). The page is organized in 8-bit or 16-bit words.
The page size corresponds to the number of words in the main data plus the number of words
in the extra area used for redundancy.
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
The only configuration required for ECC is the NAND Flash or the SmartMedia page size
(528/1056/2112/4224). Page size is configured setting the PAGESIZE field in the ECC Mode
Register (ECC_MR).
ECC is automatically computed as soon as a read (00h)/write (80h) command to the NAND
Flash or the SmartMedia is detected. Read and write access must start at a page boundary.
ECC is computed as soon as the counter reaches the page size. Values in the ECC Parity
Register (ECC_PR) and ECC NParity Register (ECC_NPR) are then valid and locked until a
new start condition (read/write command followed by five access address cycles).
23.3.1
Write Access
Once the flash memory page is written, the computed ECC code is available in the ECC Parity
Error (ECC_PR) and ECC_NParity Error (ECC_NPR) registers. The ECC code value must be
written by the software application at the end of the page, in the extra area used for
redundancy.
23.3.2
Read Access
After reading main data in the page area, the application can perform read access to the extra
area used for redundancy. Error detection is automatically performed by the ECC controller.
The application can check the ECC Status Register (ECC_SR) for any detected errors.
It is up to the application to correct any detected error. ECC computation can detect four different circumstances:
• No error: XOR between the ECC computation and the ECC code stored at the end of the
NAND Flash or SmartMedia page is equal to 0. No error flags in the ECC Status Register
(ECC_SR).
• Recoverable error: Only the RECERR flag in the ECC Status register (ECC_SR) is set. The
corrupted word offset in the read page is defined by the WORDADDR field in the ECC
Parity Register (ECC_PR). The corrupted bit position in the concerned word is defined in
the BITADDR field in the ECC Parity Register (ECC_PR).
• ECC error: The ECCERR flag in the ECC Status Register is set. An error has been
detected in the ECC code stored in the Flash memory. The position of the corrupted bit can
be found by the application performing an XOR between the Parity and the NParity
contained in the ECC code stored in the flash memory.
• Non correctable error: The MULERR flag in the ECC Status Register is set. Several
unrecoverable errors have been detected in the flash memory page.
ECC Status Register, ECC Parity Register and ECC NParity Register are cleared when a
read/write command is detected or a software register is enabled.
For single bit Error Correction and double bit Error Detection (SEC-DED) hsiao code is used.
32-bit ECC is generated in order to perform one bit correction per 512/1024/2048/4096 8- or
16-bit words. Of the 32 ECC bits, 26 bits are for line parity and 6 bits are for column parity.
They are generated according to the schemes shown in Figure 23-2 and Figure 23-3.
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Figure 23-2. Parity Generation for 512/1024/2048/4096 8-bit Words1
1st byte
2nd byte
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
P8
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
P8'
3rd byte
Bit7
Bit7
Bit6
Bit6
Bit5
Bit5
Bit4
Bit4
Bit3
Bit3
Bit2
Bit2
Bit1
Bit1
Bit0
Bit0
P8
Bit7
Bit7
Bit6
Bit6
Bit5
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
P8
Bit4
Bit3
Bit2
Bit1
Bit0
P8'
Bit7
Bit5
Bit5
Bit3
Bit3
Bit2
P8
Bit2
Bit1
Bit1
Bit0
Bit7
Bit6
Bit6
Bit0
P8'
P1
P1'
P1
P1
P1'
P1
P1'
4 th byte
(page size -3 )th byte
(page size -2 )th byte
(page size -1 )th byte
Page size th byte
P2
Bit4
Bit4
P1'
P2
P2'
P4
Page size
Page size
Page size
Page size
= 512
= 1024
= 2048
= 4096
P8'
P16
P32
PX
P32
PX'
P16'
P16
P16'
P2'
P4'
P1=bit7(+)bit5(+)bit3(+)bit1(+)P1
P2=bit7(+)bit6(+)bit3(+)bit2(+)P2
P4=bit7(+)bit6(+)bit5(+)bit4(+)P4
P1'=bit6(+)bit4(+)bit2(+)bit0(+)P1'
P2'=bit5(+)bit4(+)bit1(+)bit0(+)P2'
P4'=bit7(+)bit6(+)bit5(+)bit4(+)P4'
Px = 2048
Px = 4096
Px = 8192
Px = 16384
To calculate P8’ to PX’ and P8 to PX, apply the algorithm that follows.
Page size = 2n
for i =0 to n
begin
for (j = 0 to page_size_byte)
begin
if(j[i] ==1)
P[2i+3]=bit7(+)bit6(+)bit5(+)bit4(+)bit3(+)
bit2(+)bit1(+)bit0(+)P[2i+3]
else
P[2i+3]’=bit7(+)bit6(+)bit5(+)bit4(+)bit3(+)
bit2(+)bit1(+)bit0(+)P[2i+3]'
end
end
251
6249B–ATARM–14-Dec-06
6249B–ATARM–14-Dec-06
(Page size -3 )th word
(Page size -2 )th word
(Page size -1 )th word
Page size th word
3rd word
4th word
1st word
2nd word
(+)
AT91SAM9263 Preliminary
Figure 23-3. Parity Generation for 512/1024/2048/4096 16-bit Words
252
AT91SAM9263 Preliminary
To calculate P8’ to PX’ and P8 to PX, apply the algorithm that follows.
Page size = 2n
for i =0 to n
begin
for (j = 0 to page_size_word)
begin
if(j[i] ==1)
P[2i+3]= bit15(+)bit14(+)bit13(+)bit12(+)
bit11(+)bit10(+)bit9(+)bit8(+)
bit7(+)bit6(+)bit5(+)bit4(+)bit3(+)
bit2(+)bit1(+)bit0(+)P[2n+3]
else
P[2i+3]’=bit15(+)bit14(+)bit13(+)bit12(+)
bit11(+)bit10(+)bit9(+)bit8(+)
bit7(+)bit6(+)bit5(+)bit4(+)bit3(+)
bit2(+)bit1(+)bit0(+)P[2i+3]'
end
end
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
23.4
Error Corrected Code (ECC) Controller User Interface
Table 23-1.
Offset
Register Mapping
Register
Register Name
Access
Reset
0x00
ECC Control Register
ECC_CR
Write-only
0x0
0x04
ECC Mode Register
ECC_MR
Read/Write
0x0
0x8
ECC Status Register
ECC_SR
Read-only
0x0
0x0C
ECC Parity Register
ECC_PR
Read-only
0x0
0x10
ECC NParity Register
ECC_NPR
Read-only
0x0
–
–
0x14 - 0xFC
Reserved
–
254
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
23.4.1
ECC Control Register
Name:
ECC_CR
Access Type:
Write-only
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
–
28
–
20
–
12
–
4
–
27
–
19
–
11
–
3
–
26
–
18
–
10
–
2
–
25
–
17
–
9
–
1
–
24
–
16
–
8
–
0
RST
28
–
20
–
12
–
4
–
27
–
19
–
11
–
3
–
26
–
18
–
10
–
2
–
25
–
17
–
9
–
1
24
–
16
–
8
–
0
• RST: RESET Parity
Provides reset to current ECC by software.
1: Resets ECC Parity and ECC NParity register
0: No effect
23.4.2
ECC Mode Register
Register Name:
ECC_MR
Access Type:
Read/Write
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
–
PAGESIZE
• PAGESIZE: Page Size
This field defines the page size of the NAND Flash device.
Page Size
Description
00
528 words
01
1056 words
10
2112 words
11
4224 words
A word has a value of 8 bits or 16 bits, depending on the NAND Flash or Smartmedia memory organization.
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
23.4.3
ECC Status Register
Register Name:
ECC_SR
Access Type:
Read-only
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
–
28
–
20
–
12
–
4
–
27
–
19
–
11
–
3
–
26
–
18
–
10
–
2
MULERR
25
–
17
–
9
–
1
ECCERR
24
–
16
–
8
–
0
RECERR
• RECERR: Recoverable Error
0 = No Errors Detected
1 = Errors Detected. If MUL_ERROR is 0, a single correctable error was detected. Otherwise multiple uncorrected errors
were detected
• ECCERR: ECC Error
0 = No Errors Detected
1 = A single bit error occurred in the ECC bytes.
Read both ECC Parity and ECC NParity register, the error occurred at the location which contains a 1 in the least significant 16 bits.
• MULERR: Multiple Error
0 = No Multiple Errors Detected
1 = Multiple Errors Detected
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
23.4.4
ECC Parity Register
Register Name:
ECC_PR
Access Type:
Read-only
31
–
23
–
15
30
–
22
–
14
29
–
21
–
13
28
–
20
–
12
27
–
19
–
11
26
–
18
–
10
3
2
25
–
17
–
9
24
–
16
–
8
1
0
WORDADDR
7
6
5
4
WORDADDR
BITADDR
During a page write, the value of the entire register must be written in the extra area used for redundancy (for a 512-byte
page size: address 512-513)
• BITADDR
During a page read, this value contains the corrupted bit offset where an error occurred, if a single error was detected. If
multiple errors were detected, this value is meaningless.
• WORDADDR
During a page read, this value contains the word address (8-bit or 16-bit word depending on the memory plane organization) where an error occurred, if a single error was detected. If multiple errors were detected, this value is meaningless.
23.4.5
ECC NParity Register
Register Name:
ECC_NPR
Access Type:
Read-only
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
NPARITY
NPARITY
• NPARITY
During a write, the value of this register must be written in the extra area used for redundancy (for a 512-byte page size:
address 514-515)
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6249B–ATARM–14-Dec-06
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AT91SAM9263 Preliminary
24. DMA Controller (DMAC)
24.1
Description
The DMA Controller (DMAC) is an AHB-central DMA controller core that transfers data from a
source peripheral to a destination peripheral over one or more AMBA buses. One channel is
required for each source/destination pair. In the most basic configuration, the DMAC has one
master interface and one channel. The master interface reads the data from a source and
writes it to a destination. Two AMBA transfers are required for each DMA data transfer. This is
also known as a dual-access transfer.
The DMAC is programmed via the AHB slave interface.
24.2
Block Diagram
Figure 24-1. DMA Controller (DMAC) Block Diagram
DMA Controller
AHB Slave
AHB Slave
Interface
Interrupt
Generator
CFG
irq_dma
Channel 1
Channel 0
AHB Master
AHB Master
Interface
FIFO
SRC
FSM
Hardware
Handshaking
Interface
DMARQ0..3
24.3
24.3.1
DST
FSM
Functional Description
Basic Definitions
Source peripheral: Device on an AMBA layer from where the DMAC reads data, which is
then stored in the channel FIFO. The source peripheral teams up with a destination peripheral
to form a channel.
Destination peripheral: Device to which the DMAC writes the stored data from the FIFO (previously read from the source peripheral).
259
6249B–ATARM–14-Dec-06
Memory: Source or destination that is always “ready” for a DMA transfer and does not require
a handshaking interface to interact with the DMAC. A peripheral should be assigned as memory only if it does not insert more than 16 wait states. If more than 16 wait states are required,
then the peripheral should use a handshaking interface (the default if the peripheral is not programmed to be memory) in order to signal when it is ready to accept or supply data.
Channel: Read/write datapath between a source peripheral on one configured AMBA layer
and a destination peripheral on the same or different AMBA layer that occurs through the
channel FIFO. If the source peripheral is not memory, then a source handshaking interface is
assigned to the channel. If the destination peripheral is not memory, then a destination handshaking interface is assigned to the channel. Source and destination handshaking interfaces
can be assigned dynamically by programming the channel registers.
Master interface: DMAC is a master on the AHB bus reading data from the source and writing
it to the destination over the AHB bus.
Slave interface: The AHB interface over which the DMAC is programmed. The slave interface
in practice could be on the same layer as any of the master interfaces or on a separate layer.
Handshaking interface: A set of signal registers that conform to a protocol and handshake
between the DMAC and source or destination peripheral to control the transfer of a single or
burst transaction between them. This interface is used to request, acknowledge, and control a
DMAC transaction. A channel can receive a request through one of three types of handshaking interface: hardware, software, or peripheral interrupt.
Hardware handshaking interface: Uses hardware signals to control the transfer of a single
or burst transaction between the DMAC and the source or destination peripheral.
Software handshaking interface: Uses software registers to control the transfer of a single
or burst transaction between the DMAC and the source or destination peripheral. No special
DMAC handshaking signals are needed on the I/O of the peripheral. This mode is useful for
interfacing an existing peripheral to the DMAC without modifying it.
Peripheral interrupt handshaking interface: A simple use of the hardware handshaking
interface. In this mode, the interrupt line from the peripheral is tied to the dma_req input of the
hardware handshaking interface. Other interface signals are ignored.
Flow controller: The device (either the DMAC or source/destination peripheral) that determines the length of and terminates a DMA block transfer. If the length of a block is known
before enabling the channel, then the DMAC should be programmed as the flow controller. If
the length of a block is not known prior to enabling the channel, the source or destination
peripheral needs to terminate a block transfer. In this mode, the peripheral is the flow
controller.
Flow control mode (DMAC_CFGx.FCMODE): Special mode that only applies when the destination peripheral is the flow controller. It controls the pre-fetching of data from the source
peripheral.
Transfer hierarchy: Figure 24-2 on page 261 illustrates the hierarchy between DMAC transfers, block transfers, transactions (single or burst), and AMBA transfers (single or burst) for
non-memory peripherals. Figure 24-3 on page 261 shows the transfer hierarchy for memory.
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AT91SAM9263 Preliminary
Figure 24-2. DMAC Transfer Hierarchy for Non-Memory Peripheral
DMAC Transfer
Block
Block
Burst
Transaction
DMA Transfer
Level
Burst
Transaction
Burst
Transaction
AMBA
Burst
Transfer
AMBA
Burst
Transfer
AMBA
Burst
Transfer
Block Transfer
Level
Block
Single
Transaction
AMBA
Single
Transfer
AMBA
Single
Transfer
DMA Transaction
Level
AMBA Transfer
Level
Figure 24-3. DMAC Transfer Hierarchy for Memory
DMA Transfer
Level
DMAC Transfer
Block
AMBA
Burst
Transfer
Block
AMBA
Burst
Transfer
Block Transfer
Level
Block
AMBA
Burst
Transfer
AMBA
Single
Transfer
AMBA Transfer
Level
Block: A block of DMAC data. The amount of data (block length) is determined by the flow
controller. For transfers between the DMAC and memory, a block is broken directly into a
sequence of AMBA bursts and AMBA single transfers. For transfers between the DMAC and a
non-memory peripheral, a block is broken into a sequence of DMAC transactions (single and
bursts). These are in turn broken into a sequence of AMBA transfers.
Transaction: A basic unit of a DMAC transfer as determined by either the hardware or software handshaking interface. A transaction is only relevant for transfers between the DMAC
and a source or destination peripheral if the source or destination peripheral is a non-memory
device. There are two types of transactions: single and burst.
– Single transaction: The length of a single transaction is always 1 and is
converted to a single AMBA transfer.
– Burst transaction: The length of a burst transaction is programmed into the
DMAC. The burst transaction is converted into a sequence of AMBA bursts and
AMBA single transfers. DMAC executes each AMBA burst transfer by performing
incremental bursts that are no longer than the maximum AMBA burst size set. The
burst transaction length is under program control and normally bears some
261
6249B–ATARM–14-Dec-06
relationship to the FIFO sizes in the DMAC and in the source and destination
peripherals.
DMA transfer: Software controls the number of blocks in a DMAC transfer. Once the DMA
transfer has completed, then hardware within the DMAC disables the channel and can generate an interrupt to signal the completion of the DMA transfer. You can then re-program the
channel for a new DMA transfer.
Single-block DMA transfer: Consists of a single block.
Multi-block DMA transfer: A DMA transfer may consist of multiple DMAC blocks. Multi-block
DMA transfers are supported through block chaining (linked list pointers), auto-reloading of
channel registers, and contiguous blocks. The source and destination can independently
select which method to use.
– Linked lists (block chaining) – A linked list pointer (LLP) points to the location in
system memory where the next linked list item (LLI) exists. The LLI is a set of
registers that describe the next block (block descriptor) and an LLP register. The
DMAC fetches the LLI at the beginning of every block when block chaining is
enabled.
– Auto-reloading – The DMAC automatically reloads the channel registers at the
end of each block to the value when the channel was first enabled.
– Contiguous blocks – Where the address between successive blocks is selected
to be a continuation from the end of the previous block.
Scatter: Relevant to destination transfers within a block. The destination AMBA address is
incremented/decremented by a programmed amount when a scatter boundary is reached.
The number of AMBA transfers between successive scatter boundaries is under software
control.
Gather: Relevant to source transfers within a block. The source AMBA address is incremented/decremented by a programmed amount when a gather boundary is reached. The
number of AMBA transfers between successive gather boundaries is under software control.
Channel locking: Software can program a channel to keep the AHB master interface by locking the arbitration for the master bus interface for the duration of a DMA transfer, block, or
transaction (single or burst).
Bus locking: Software can program a channel to maintain control of the AMBA bus by asserting hlock for the duration of a DMA transfer, block, or transaction (single or burst). Channel
locking is asserted for the duration of bus locking at a minimum.
FIFO mode: Special mode to improve bandwidth. When enabled, the channel waits until the
FIFO is less than half full to fetch the data from the source peripheral and waits until the FIFO
is greater than or equal to half full to send data to the destination peripheral. Thus, the channel
can transfer the data using AMBA bursts, eliminating the need to arbitrate for the AHB master
interface for each single AMBA transfer. When this mode is not enabled, the channel only
waits until the FIFO can transmit/accept a single AMBA transfer before requesting the master
bus interface.
Pseudo fly-by operation: Typically, it takes two AMBA bus cycles to complete a transfer, one
for reading the source and one for writing to the destination. However, when the source and
destination peripherals of a DMA transfer are on different AMBA layers, it is possible for the
DMAC to fetch data from the source and store it in the channel FIFO at the same time as the
DMAC extracts data from the channel FIFO and writes it to the destination peripheral. This
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activity is known as pseudo fly-by operation. For this to occur, the master interface for both
source and destination layers must win arbitration of their AHB layer. Similarly, the source and
destination peripherals must win ownership of their respective master interfaces.
24.3.2
Memory Peripherals
Figure 24-3 on page 261 shows the DMA transfer hierarchy of the DMAC for a memory peripheral. There is no handshaking interface with the DMAC, and therefore the memory peripheral
can never be a flow controller. Once the channel is enabled, the transfer proceeds immediately without waiting for a transaction request. The alternative to not having a transaction-level
handshaking interface is to allow the DMAC to attempt AMBA transfers to the peripheral once
the channel is enabled. If the peripheral slave cannot accept these AMBA transfers, it inserts
wait states onto the bus until it is ready; it is not recommended that more than 16 wait states
be inserted onto the bus. By using the handshaking interface, the peripheral can signal to the
DMAC that it is ready to transmit/receive data, and then the DMAC can access the peripheral
without the peripheral inserting wait states onto the bus.
24.3.3
Handshaking Interface
Handshaking interfaces are used at the transaction level to control the flow of single or burst
transactions. The operation of the handshaking interface is different and depends on whether
the peripheral or the DMAC is the flow controller.
The peripheral uses the handshaking interface to indicate to the DMAC that it is ready to transfer/accept data over the AMBA bus. A non-memory peripheral can request a DMA transfer
through the DMAC using one of two handshaking interfaces:
• Hardware handshaking
• Software handshaking
Software selects between the hardware or software handshaking interface on a per-channel
basis. Software handshaking is accomplished through memory-mapped registers, while hardware handshaking is accomplished using a dedicated handshaking interface.
24.3.3.1
Software Handshaking
When the slave peripheral requires the DMAC to perform a DMA transaction, it communicates
this request by sending an interrupt to the CPU or interrupt controller.
The interrupt service routine then uses the software registers to initiate and control a DMA
transaction. These software registers are used to implement the software handshaking
interface.
The HS_SEL_SRC/HS_SEL_DST bit in the DMAC_CFGx channel configuration register must
be set to enable software handshaking.
When the peripheral is not the flow controller, then the last transaction registers
DMAC_LstSrcReg and DMAC_LstDstReg are not used, and the values in these registers are
ignored.
Burst Transactions
Writing a 1 to the DMAC_ReqSrcReg[x]/DMAC_ReqDstReg[x] register is always interpreted
as a burst transaction request, where x is the channel number. However, in order for a burst
transaction request to start, software must write a 1 to the
DMAC_SglReqSrcReg[x]/DMAC_SglReqDstReg[x] register.
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You can write a 1 to the DMAC_SglReqSrcReg[x]/DMAC_SglReqDstReg[x] and
DMAC_ReqSrcReg[x]/DMAC_ReqDstReg[x] registers in any order, but both registers must be
asserted in order to initiate a burst transaction. Upon completion of the burst transaction, the
hardware clears the DMAC_SglReqSrcReg[x]/DMAC_SglReqDstReg[x] and
DMAC_ReqSrcReg[x]/DMAC_ReqDstReg[x] registers.
Single Transactions
Writing a 1 to the DMAC_SglReqSrcReg/DMAC_SglReqDstReg initiates a single transaction.
Upon
completion
of
the
single
transaction,
both
the
DMAC_SglReqSrcReg/DMAC_SglReqDstReg and DMAC_ReqSrcReg/DMAC_ReqDstReg
bits are cleared by hardware. Therefore, writing a 1 to the
DMAC_ReqSrcReg/DMAC_ReqDstReg is ignored while a single transaction has been initiated, and the requested burst transaction is not serviced.
Again, writing a 1 to the DMAC_ReqSrcReg/DMAC_ReqDstReg register is always a burst
transaction request. However, in order for a burst transaction request to start, the corresponding channel bit in the DMAC_SglReqSrcReg/DMAC_SglReqDstReg must be asserted.
Therefore, to ensure that a burst transaction is serviced, you must write a 1 to the
DMAC_ReqSrcReg/DMAC_ReqDstReg
before
writing
a
1
to
the
DMAC_SglReqSrcReg/DMAC_SglReqDstReg register.
Software can poll the relevant channel bit in the DMAC_SglReqSrcReg/
DMAC_SglReqDstReg and DMAC_ReqSrcReg/DMAC_ReqDstReg registers. When both are
0, then either the requested burst or single transaction has completed. Alternatively, the
IntSrcTran or IntDstTran interrupts can be enabled and unmasked in order to generate an
interrupt when the requested source or destination transaction has completed.
Note:
24.3.3.2
The transaction-complete interrupts are triggered when both single and burst transactions are
complete. The same transaction-complete interrupt is used for both single and burst
transactions.
Hardware Handshaking
There are 5 hardware handshaking interfaces connected to four external DMA requests (see
Table 24-1 on page 264).
Table 24-1.
Hardware Handshaking Connection
Hardware Handshaking
Interface
Request
Definition
DMAREQ0
External DMA Request 0
1
DMAREQ1
External DMA Request 1
2
DMAREQ2
External DMA Request 2
3
DMAREQ3
External DMA Request 3
4
External DMA Request Definition
When an external slave peripheral requires the DMAC to perform DMA transactions, it communicates its request by asserting the external nDMAREQx signal. This signal is
resynchronized to ensure a proper functionality (see ”External DMA Request Timing” on page
265).
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The external nDMAREQx is asserted when the source threshold level is reached. After resynchronization, the rising edge of dma_req starts the transfer. dma_req is de-asserted when
dma_ack is asserted.
The external nDMAREQx signal must be de-asserted after the last transfer and re-asserted
again before a new transaction starts.
For a source FIFO, an active edge is triggered on nDMAREQx when the source FIFO exceeds
a watermark level. For a destination FIFO, an active edge is triggered on nDMAREQx when
the destination FIFO drops below the watermark level.
The source transaction length, CTLx.SRC_MSIZE, and destination transaction length,
CTLx.DEST_MSIZE, must be set according to watermark levels on the source/destination
peripherals.
Figure 24-4. External DMA Request Timing
Hclk
DMA Transaction
nDMAREQx
dma_req
DMA Transfers
DMA Transfers
DMA Transfers
dma_ack
24.3.4
DMAC Transfer Types
A DMA transfer may consist of single or multi-block transfers. On successive blocks of a multiblock transfer, the DMAC_SARx/DMAC_DARx register in the DMAC is reprogrammed using
either of the following methods:
• Block chaining using linked lists
• Auto-reloading
• Contiguous address between blocks
On successive blocks of a multi-block transfer, the DMAC_CTLx register in the DMAC is reprogrammed using either of the following methods:
• Block chaining using linked lists
• Auto-reloading
When block chaining, using linked lists is the multi-block method of choice, and on successive
blocks, the DMAC_LLPx register in the DMAC is re-programmed using the following method:
• Block chaining using linked lists
A block descriptor (LLI) consists of following registers, DMAC_SARx, DMAC_DARx,
DMAC_LLPx, DMAC_CTLx. These registers, along with the DMAC_CFGx register, are used
by the DMAC to set up and describe the block transfer.
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24.3.4.1
Multi-block Transfers
Block Chaining Using Linked Lists
In this case, the DMAC re-programs the channel registers prior to the start of each block by
fetching the block descriptor for that block from system memory. This is known as an LLI
update.
DMAC block chaining is supported by using a Linked List Pointer register (DMAC_LLPx) that
stores the address in memory of the next linked list item. Each LLI (block descriptor) contains
the corresponding block descriptor (DMAC_SARx, DMAC_DARx, DMAC_LLPx,
DMAC_CTLx).
To set up block chaining, a sequence of linked lists must be programmed in memory.
The DMAC_SARx, DMAC_DARx, DMAC_LLPx and DMAC_CTLx registers are fetched from
system memory on an LLI update. Figure 24-5 on page 266 shows how to use chained linked
lists in memory to define multi-block transfers using block chaining.
The Linked List multi-block transfers is initiated by programming DMAC_LLPx with LLPx(0)
( L L I ( 0 ) b a s e a d d r e s s ) a n d D M AC _ C T L x w i t h D M A C _ C T L x . L L P _ S _ E N a n d
DMAC_CTLx.LLP_D_EN.
Figure 24-5. Multi-block Transfer Using Linked Lists
LLI(0)
LLPx(0)
266
System Memory
LLI(1)
CTLx[63..32]
CTLx[63..32]
CTLx[31..0]
CTLx[31..0]
LLPx(1)
LLPx(2)
DARx
DARx
SARx
SARx
LLPx(2)
LLPx(1)
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Table 24-2.
Programming of Transfer Types and Channel Register Update Method (DMAC State Machine Table)
Transfer Type
1) Single Block or
last transfer of
multi-Block
2) AutoReload
multi-block transfer
with contiguous
SAR
3) AutoReload
multi-block transfer
with contiguous
DAR
4) AutoReload
multi-block transfer
6) Linked List
multi-block transfer
with contiguous
SAR
7) Linked List
multi-block transfer
with auto-reload
SAR
8) Linked List
multi-block transfer
with contiguous
DAR
9) Linked List
multi-block transfer
with auto-reload
DAR
10) Linked List
multi-block transfer
LLP.
LLP_S_EN
RELOAD
_SR
LLP_D_EN
RELOAD_
DS
DMAC_CTLx,
DMAC_LLPx
LOC
(DMAC_
CTLx)
(DMAC_
CFGx)
(DMAC_
CTLx)
(DMAC_
CFGx)
Update
=0
Yes
0
0
0
0
None, user
reprograms
None (single)
None
(single)
–
1
DMAC_CTLx,D
MAC_LLPx are
reloaded from
initial values.
Contiguous
AutoReload
–
0
DMAC_CTLx,D
MAC_LLPx are
reloaded from
initial values.
Auto-Reload
Contiguous
–
1
DMAC_CTLx,D
MAC_LLPx are
reloaded from
initial values.
Auto-Reload
AutoReload
–
0
DMAC_CTLx,D
MAC_LLPx
loaded from
next Linked List
item
Contiguous
Linked
List
–
0
DMAC_CTLx,D
MAC_LLPx
loaded from
next Linked List
item
Auto-Reload
Linked
List
–
0
DMAC_CTLx,D
MAC_LLPx
loaded from
next Linked List
item
Linked List
Contiguous
–
1
DMAC_CTLx,D
MAC_LLPx
loaded from
next Linked List
item
Linked List
AutoReload
–
0
DMAC_CTLx,D
MAC_LLPx
loaded from
next Linked List
item
Linked List
Linked
List
–
Yes
Yes
Yes
No
No
No
No
No
0
0
0
0
0
1
1
1
0
1
1
0
1
0
0
0
0
0
0
1
1
0
0
1
Method
DMAC_SARx
Update
Method
DMAC_
DARx
Update
Method
–
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Auto-reloading of Channel Registers
During auto-reloading, the channel registers are reloaded with their initial values at the completion of each block and the new values used for the new block. Depending on the row
number in Table 24-2 on page 267, some or all of the DMAC_SARx, DMAC_DARx and
DMAC_CTLx channel registers are reloaded from their initial value at the start of a block
transfer.
Contiguous Address Between Blocks
In this case, the address between successive blocks is selected to be a continuation from the
end of the previous block. Enabling the source or destination address to be contiguous
between blocks is a function of DMAC_CTLx.LLP_S_EN, DMAC_CFGx.RELOAD_SR,
DMAC_CTLx.LLP_D_EN, and DMAC_CFGx.RELOAD_DS registers (see Figure 24-2 on
page 267).
Note:
Both DMAC_SARx and DMAC_DARx updates cannot be selected to be contiguous. If this functionality is required, the size of the Block Transfer (DMAC_CTLx.BLOCK_TS) must be
increased. If this is at the maximum value, use Row 10 of Table 24-2 on page 267 and setup the
LLI.DMAC_SARx address of the block descriptor to be equal to the end DMAC_SARx address
of the previous block. Similarly, setup the LLI.DMAC_DARx address of the block descriptor to be
equal to the end DMAC_DARx address of the previous block.
Suspension of Transfers Between Blocks
At the end of every block transfer, an end of block interrupt is asserted if:
• interrupts are enabled, DMAC_CTLx.INT_EN = 1
• the channel block interrupt is unmasked, DMAC_MaskBlock[n] = 0, where n is the channel
number.
Note:
The block complete interrupt is generated at the completion of the block transfer to the
destination.
For rows 6, 8, and 10 of Table 24-2 on page 267, the DMA transfer does not stall between
block transfers. For example, at the end of block N, the DMAC automatically proceeds to block
N + 1.
For rows 2, 3, 4, 7, and 9 of Table 24-2 on page 267 (DMAC_SARx and/or DMAC_DARx autoreloaded between block transfers), the DMA transfer automatically stalls after the end of block.
Interrupt is asserted if the end of block interrupt is enabled and unmasked.
The DMAC does not proceed to the next block transfer until a write to the block interrupt clear
register, DMAC_ClearBlock[n], is performed by software. This clears the channel block complete interrupt.
For rows 2, 3, 4, 7, and 9 of Table 24-2 on page 267 (DMAC_SARx and/or DMAC_DARx autoreloaded between block transfers), the DMA transfer does not stall if either:
• interrupts are disabled, DMAC_CTLx.INT_EN = 0, or
• the channel block interrupt is masked, DMAC_MaskBlock[n] = 1, where n is the channel
number.
Channel suspension between blocks is used to ensure that the end of block ISR (interrupt service routine) of the next-to-last block is serviced before the start of the final block commences.
This ensures that the ISR has cleared the DMAC_CFGx.RELOAD_SR and/or
DMAC_CFGx.RELOAD_DS bits before completion of the final block. The reload bits
DMAC_CFGx.RELOAD_SR and/or DMAC_CFGx.RELOAD_DS should be cleared in the ‘end
of block ISR’ for the next-to-last block transfer.
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24.3.4.2
Ending Multi-block Transfers
All multi-block transfers must end as shown in Row 1 of Table 24-2 on page 267. At the end of
every block transfer, the DMAC samples the row number, and if the DMAC is in Row 1 state,
then the previous block transferred was the last block and the DMA transfer is terminated.
For rows 2,3 and 4 of Table 24-2 on page 267, (DMAC_LLPx = 0 and
DMAC_CFGx.RELOAD_SR and/or DMAC_CFGx.RELOAD_DS is set), multi-block DMA
transfers continue until both the DMAC_CFGx.RELOAD_SR and DMAC_CFGx.RELOAD_DS
registers are cleared by software. They should be programmed to zero in the end of block
interrupt service routine that services the next-to-last block transfer. This puts the DMAC into
Row 1 state.
For rows 6, 8, and 10 (both DMAC_CFGx.RELOAD_SR and
DMAC_CFGx.RELOAD_DS cleared) the user must setup the last block descriptor in
memory such that both LLI.DMAC_CTLx.LLP_S_EN and
LLI.DMAC_CTLx.LLP_D_EN are zero. For rows 7 and 9, the end-of-block interrupt
service routine that services the next-to-last block transfer should clear the
DMAC_CFGx.RELOAD_SR and DMAC_CFGx.RELOAD_DS reload bits. The last
block descriptor in memory should be set up so that both the
LLI.DMAC_CTLx.LLP_S_EN and LLI.DMAC_CTLx.LLP_D_EN are zero.
Note:
24.3.5
Programming a Channel
Three registers, the DMAC_LLPx, the DMAC_CTLx and DMAC_CFGx, need to be programmed to set up whether single or multi-block transfers take place, and which type of multiblock transfer is used. The different transfer types are shown in Table 24-2 on page 267.
The “Update Method” column indicates where the values of DMAC_SARx, DMAC_DARx,
DMAC_CTLx, and DMAC_LLPx are obtained for the next block transfer when multi-block
DMAC transfers are enabled.
Note:
In Table 24-2 on page 267, all other combinations of DMAC_LLPx.LOC = 0,
DMAC_CTLx.LLP_S_EN, DMAC_CFGx.RELOAD_SR, DMAC_CTLx.LLP_D_EN, and
DMAC_CFGx.RELOAD_DS are illegal, and causes indeterminate or erroneous behavior.
24.3.5.1
Programming Examples
Single-block Transfer (Row 1)
1. Read the Channel Enable register to choose a free (disabled) channel.
2. Clear any pending interrupts on the channel from the previous DMA transfer by writing to the Interrupt Clear registers: DMAC_ClearTfr, DMAC_ClearBlock,
DMAC_ClearSrcTran, DMAC_ClearDstTran, DMAC_ClearErr. Reading the Interrupt
Raw Status and Interrupt Status registers confirms that all interrupts have been
cleared.
3. Program the following channel registers:
a. Write the starting source address in the DMAC_SARx register for channel x.
b.
Write the starting destination address in the DMAC_DARx register for channel x.
c.
Program DMAC_CTLx and DMAC_CFGx according to Row 1 as shown in Table
24-2 on page 267. Program the DMAC_LLPx register with ‘0’.
d. Write the control information for the DMA transfer in the DMAC_CTLx register for
channel x. For example, in the register, you can program the following:
– i. Set up the transfer type (memory or non-memory peripheral for source and
destination) and flow control device by programming the TT_FC of the
DMAC_CTLx register.
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6249B–ATARM–14-Dec-06
– ii. Set up the transfer characteristics, such as:
– Transfer width for the source in the SRC_TR_WIDTH field.
– Transfer width for the destination in the DST_TR_WIDTH field.
– Source master layer in the SMS field where source resides.
– Destination master layer in the DMS field where destination resides.
– Incrementing/decrementing or fixed address for source in SINC field.
– Incrementing/decrementing or fixed address for destination in DINC field.
e. Write the channel configuration information into the DMAC_CFGx register for
channel x.
– i. Designate the handshaking interface type (hardware or software) for the source
and destination peripherals. This is not required for memory. This step requires
programming the HS_SEL_SRC/HS_SEL_DST bits, respectively. Writing a ‘0’
activates the hardware handshaking interface to handle source/destination
requests. Writing a ‘1’ activates the software handshaking interface to handle
source/destination requests.
– ii. If the hardware handshaking interface is activated for the source or destination
peripheral, assign a handshaking interface to the source and destination
peripheral. This requires programming the SRC_PER and DEST_PER bits,
respectively.
f.
If gather is enabled (DMAC_CTLx.S_GATH_EN is enabled), program the
DMAC_SGRx register for channel x.
g. If scatter is enabled (DMAC_CTLx.D_SCAT_EN, program the DMAC_DSRx register for channel x.
4. After the DMAC selected channel has been programmed, enable the channel by writing a ‘1’ to the DMAC_ChEnReg.CH_EN bit. Make sure that bit 0 of the
DMAC_DmaCfgReg register is enabled.
5. Source and destination request single and burst DMA transactions to transfer the
block of data (assuming non-memory peripherals). The DMAC acknowledges at the
completion of every transaction (burst and single) in the block and carry out the block
transfer.
6. Once the transfer completes, hardware sets the interrupts and disables the channel.
At this time you can either respond to the Block Complete or Transfer Complete interrupts, or poll for the Channel Enable (DMAC_ChEnReg.CH_EN) bit until it is cleared
by hardware, to detect when the transfer is complete.
Multi-block Transfer with Linked List for Source and Linked List for Destination (Row 10)
1. Read the Channel Enable register to choose a free (disabled) channel.
2. Set up the chain of Linked List Items (otherwise known as block descriptors) in memory. Write the control information in the LLI.DMAC_CTLx register location of the block
descriptor for each LLI in memory (see Figure 24-5 on page 266) for channel x. For
example, in the register, you can program the following:
a. Set up the transfer type (memory or non-memory peripheral for source and destination) and flow control device by programming the TT_FC of the DMAC_CTLx
register.
b.
Set up the transfer characteristics, such as:
– i. Transfer width for the source in the SRC_TR_WIDTH field.
– ii. Transfer width for the destination in the DST_TR_WIDTH field.
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– iii. Source master layer in the SMS field where source resides.
– iv. Destination master layer in the DMS field where destination resides.
– v. Incrementing/decrementing or fixed address for source in SINC field.
– vi. Incrementing/decrementing or fixed address for destination DINC field.
3. Write the channel configuration information into the DMAC_CFGx register for channel
x.
a. Designate the handshaking interface type (hardware or software) for the source
and destination peripherals. This is not required for memory. This step requires
programming the HS_SEL_SRC/HS_SEL_DST bits, respectively. Writing a ‘0’
activates the hardware handshaking interface to handle source/destination
requests for the specific channel. Writing a ‘1’ activates the software handshaking
interface to handle source/destination requests.
b.
If the hardware handshaking interface is activated for the source or destination
peripheral, assign the handshaking interface to the source and destination
peripheral. This requires programming the SRC_PER and DEST_PER bits,
respectively.
4. Make sure that the LLI.DMAC_CTLx register locations of all LLI entries in memory
(except the last) are set as shown in Row 10 of Table 24-2 on page 267. The
LLI.DMAC_CTLx register of the last Linked List Item must be set as described in Row
1 of Table 24-2. Figure 24-7 on page 273 shows a Linked List example with two list
items.
5. Make sure that the LLI.DMAC_LLPx register locations of all LLI entries in memory
(except the last) are non-zero and point to the base address of the next Linked List
Item.
6. Make sure that the LLI.DMAC_SARx/LLI.DMAC_DARx register locations of all LLI
entries in memory point to the start source/destination block address preceding that
LLI fetch.
7. Make sure that the LLI.DMAC_CTLx.DONE field of the LLI.DMAC_CTLx register
locations of all LLI entries in memory are cleared.
8. If gather is enabled (DMAC_CTLx.S_GATH_EN is enabled), program the
DMAC_SGRx register for channel x.
9. If scatter is enabled (DMAC_CTLx.D_SCAT_EN is enabled), program the
DMAC_DSRx register for channel x.
10. Clear any pending interrupts on the channel from the previous DMA transfer by writing to the Interrupt Clear registers: DMAC_ClearTfr, DMAC_ClearBlock,
DMAC_ClearSrcTran, DMAC_ClearDstTran, DMAC_ClearErr. Reading the Interrupt
Raw Status and Interrupt Status registers confirms that all interrupts have been
cleared.
11. Program the DMAC_CTLx, DMAC_CFGx registers according to Row 10 as shown in
Table 24-2 on page 267.
12. Program the DMAC_LLPx register with DMAC_LLPx(0), the pointer to the first Linked
List item.
13. Finally, enable the channel by writing a ‘1’ to the DMAC_ChEnReg.CH_EN bit. The
transfer is performed.
14. The DMAC fetches the first LLI from the location pointed to by DMAC_LLPx(0).
Note:
The LLI.DMAC_SARx, LLI. DMAC_DARx, LLI.DMAC_LLPx and LLI.DMAC_CTLx registers are
fetched. The DMAC automatically reprograms the DMAC_SARx, DMAC_DARx, DMAC_LLPx
and DMAC_CTLx channel registers from the DMAC_LLPx(0).
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15. Source and destination request single and burst DMA transactions to transfer the
block of data (assuming non-memory peripheral). The DMAC acknowledges at the
completion of every transaction (burst and single) in the block and carry out the block
transfer.
16. The DMAC does not wait for the block interrupt to be cleared, but continues fetching
the next LLI from the memory location pointed to by current DMAC_LLPx register and
automatically reprograms the DMAC_SARx, DMAC_DARx, DMAC_LLPx and
DMAC_CTLx channel registers. The DMA transfer continues until the DMAC determines that the DMAC_CTLx and DMAC_LLPx registers at the end of a block transfer
match that described in Row 1 of Table 24-2 on page 267. The DMAC then knows
that the previous block transferred was the last block in the DMA transfer. The DMA
transfer might look like that shown in Figure 24-6 on page 272.
Figure 24-6. Multi-Block with Linked List Address for Source and Destination
Address of
Destination Layer
Address of
Source Layer
Block 2
Block 2
SAR(2)
DAR(2)
Block 1
Block 1
SAR(1)
DAR(1)
Block 0
Block 0
DAR(0)
SAR(0)
Source Blocks
Destination Blocks
If the user needs to execute a DMA transfer where the source and destination address are
contiguous but the amount of data to be transferred is greater than the maximum block size
DMAC_CTLx.BLOCK_TS, then this can be achieved using the type of multi-block transfer as
shown in Figure 24-7 on page 273.
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Figure 24-7. Multi-Block with Linked Address for Source and Destination Blocks are Contiguous
Address of
Source Layer
Address of
Destination Layer
Block 2
DAR(3)
Block 2
Block 2
SAR(3)
DAR(2)
Block 2
Block 1
SAR(2)
DAR(1)
Block 1
SAR(1)
Block 0
DAR(0)
Block 0
SAR(0)
Source Blocks
Destination Blocks
The DMA transfer flow is shown in Figure 24-8 on page 274.
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6249B–ATARM–14-Dec-06
Figure 24-8. DMA Transfer Flow for Source and Destination Linked List Address
Channel enabled by
software
LLI Fetch
Hardware reprograms
SARx, DARx, CTLx, LLPx
DMAC block transfer
Source/destination
status fetch
Block Complete interrupt
generated here
Is DMAC in
Row1 of
DMAC State Machine Table?
DMAC transfer Complete
interrupt generated here
no
yes
Channel Disabled by
hardware
Multi-block Transfer with Source Address Auto-reloaded and Destination Address Auto-reloaded (Row 4)
1. Read the Channel Enable register to choose an available (disabled) channel.
2. Clear any pending interrupts on the channel from the previous DMA transfer by writing to the Interrupt Clear registers: DMAC_ClearTfr, DMAC_ClearBlock,
DMAC_ClearSrcTran, DMAC_ClearDstTran, DMAC_ClearErr. Reading the Interrupt
Raw Status and Interrupt Status registers confirms that all interrupts have been
cleared.
3. Program the following channel registers:
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AT91SAM9263 Preliminary
a. Write the starting source address in the DMAC_SARx register for channel x.
b.
Write the starting destination address in the DMAC_DARx register for channel x.
c.
Program DMAC_CTLx and DMAC_CFGx according to Row 4 as shown in Table
24-2 on page 267. Program the DMAC_LLPx register with ‘0’.
d. Write the control information for the DMA transfer in the DMAC_CTLx register for
channel x. For example, in the register, you can program the following:
– i. Set up the transfer type (memory or non-memory peripheral for source and
destination) and flow control device by programming the TT_FC of the
DMAC_CTLx register.
– ii. Set up the transfer characteristics, such as:
– Transfer width for the source in the SRC_TR_WIDTH field.
– Transfer width for the destination in the DST_TR_WIDTH field.
– Source master layer in the SMS field where source resides.
– Destination master layer in the DMS field where destination resides.
– Incrementing/decrementing or fixed address for source in SINC field.
– Incrementing/decrementing or fixed address for destination in DINC field.
e. If gather is enabled (DMAC_CTLx.S_GATH_EN is enabled), program the
DMAC_SGRx register for channel x.
f.
If scatter is enabled (DMAC_CTLx.D_SCAT_EN), program the DMAC_DSRx register for channel x.
g. Write the channel configuration information into the DMAC_CFGx register for
channel x. Ensure that the reload bits, DMAC_CFGx. RELOAD_SR and
DMAC_CFGx.RELOAD_DS are enabled.
– i. Designate the handshaking interface type (hardware or software) for the source
and destination peripherals. This is not required for memory. This step requires
programming the HS_SEL_SRC/HS_SEL_DST bits, respectively. Writing a ‘0’
activates the hardware handshaking interface to handle source/destination
requests for the specific channel. Writing a ‘1’ activates the software handshaking
interface to handle source/destination requests.
– ii. If the hardware handshaking interface is activated for the source or destination
peripheral, assign handshaking interface to the source and destination peripheral.
This requires programming the SRC_PER and DEST_PER bits, respectively.
4. After the DMAC selected channel has been programmed, enable the channel by writing a ‘1’ to the DMAC_ChEnReg.CH_EN bit. Make sure that bit 0 of the
DMAC_DmaCfgReg register is enabled.
5. Source and destination request single and burst DMAC transactions to transfer the
block of data (assuming non-memory peripherals). The DMAC acknowledges on
completion of each burst/single transaction and carry out the block transfer.
6. When the block transfer has completed, the DMAC reloads the DMAC_SARx,
DMAC_DARx and DMAC_CTLx registers. Hardware sets the Block Complete interrupt. The DMAC then samples the row number as shown in Table 24-2 on page 267.
If the DMAC is in Row 1, then the DMA transfer has completed. Hardware sets the
transfer complete interrupt and disables the channel. So you can either respond to
the Block Complete or Transfer Complete interrupts, or poll for the Channel Enable
(DMAC_ChEnReg.CH_EN) bit until it is disabled, to detect when the transfer is complete. If the DMAC is not in Row 1, the next step is performed.
7. The DMA transfer proceeds as follows:
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6249B–ATARM–14-Dec-06
a. If interrupts are enabled (DMAC_CTLx.INT_EN = 1) and the block complete
interrupt is un-masked (DMAC_MaskBlock[x] = 1’b1, where x is the channel number) hardware sets the block complete interrupt when the block transfer has
completed. It then stalls until the block complete interrupt is cleared by software.
If the next block is to be the last block in the DMA transfer, then the block complete ISR (interrupt service routine) should clear the reload bits in the
DMAC_CFGx.RELOAD_SR and DMAC_CFGx.RELOAD_DS registers. This put
the DMAC into Row 1 as shown in Table 24-2 on page 267. If the next block is
not the last block in the DMA transfer, then the reload bits should remain enabled
to keep the DMAC in Row 4.
b.
If interrupts are disabled (DMAC_CTLx.INT_EN = 0) or the block complete interrupt is masked (DMAC_MaskBlock[x] = 1’b0, where x is the channel number),
then hardware does not stall until it detects a write to the block complete interrupt
clear register but starts the next block transfer immediately. In this case software
must clear the reload bits in the DMAC_CFGx.RELOAD_SR and
DMAC_CFGx.RELOAD_DS registers to put the DMAC into ROW 1 of Table 24-2
on page 267 before the last block of the DMA transfer has completed. The transfer is similar to that shown in Figure 24-9 on page 276. The DMA transfer flow is
shown in Figure 24-10 on page 277.
Figure 24-9. Multi-Block DMA Transfer with Source and Destination Address Auto-reloaded
Address of
Source Layer
Address of
Destination Layer
Block0
Block1
Block2
SAR
DAR
BlockN
Source Blocks
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Figure 24-10. DMA Transfer Flow for Source and Destination Address Auto-reloaded
Channel Enabled by
software
Block Transfer
Reload SARx, DARx, CTLx
Block Complete interrupt
generated here
DMAC transfer Complete
interrupt generated here
Channel Disabled by
hardware
yes
Is DMAC in Row1 of
DMAC State Machine Table?
no
CTLx.INT_EN=1
&&
MASKBLOCK[x]=1?
no
yes
Stall until block complete
interrupt cleared by software
Multi-block Transfer with Source Address Auto-reloaded and Linked List Destination Address (Row7)
1. Read the Channel Enable register to choose a free (disabled) channel.
2. Set up the chain of linked list items (otherwise known as block descriptors) in memory. Write the control information in the LLI.DMAC_CTLx register location of the block
descriptor for each LLI in memory for channel x. For example, in the register you can
program the following:
a. Set up the transfer type (memory or non-memory peripheral for source and destination) and flow control peripheral by programming the TT_FC of the
DMAC_CTLx register.
b.
Set up the transfer characteristics, such as:
– i. Transfer width for the source in the SRC_TR_WIDTH field.
– ii. Transfer width for the destination in the DST_TR_WIDTH field.
– iii. Source master layer in the SMS field where source resides.
– iv. Destination master layer in the DMS field where destination resides.
– v. Incrementing/decrementing or fixed address for source in SINC field.
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6249B–ATARM–14-Dec-06
– vi. Incrementing/decrementing or fixed address for destination DINC field.
3. Write the starting source address in the DMAC_SARx register for channel x.
Note:
The values in the LLI.DMAC_SARx register locations of each of the Linked List Items (LLIs)
setup up in memory, although fetched during a LLI fetch, are not used.
4. Write the channel configuration information into the DMAC_CFGx register for channel
x.
a. Designate the handshaking interface type (hardware or software) for the source
and destination peripherals. This is not required for memory. This step requires
programming the HS_SEL_SRC/HS_SEL_DST bits, respectively. Writing a ‘0’
activates the hardware handshaking interface to handle source/destination
requests for the specific channel. Writing a ‘1’ activates the software handshaking
interface source/destination requests.
b.
If the hardware handshaking interface is activated for the source or destination
peripheral, assign handshaking interface to the source and destination peripheral. This requires programming the SRC_PER and DEST_PER bits,
respectively.
5. Make sure that the LLI.DMAC_CTLx register locations of all LLIs in memory (except
the last) are set as shown in Row 7 of Table 24-2 on page 267 while the
LLI.DMAC_CTLx register of the last Linked List item must be set as described in Row
1 of Table 24-2. Figure 24-5 on page 266 shows a Linked List example with two list
items.
6. Make sure that the LLI.DMAC_LLPx register locations of all LLIs in memory (except
the last) are non-zero and point to the next Linked List Item.
7. Make sure that the LLI.DMAC_DARx register location of all LLIs in memory point to
the start destination block address proceeding that LLI fetch.
8. Make sure that the LLI.DMAC_CTLx.DONE field of the LLI.DMAC_CTLx register
locations of all LLIs in memory is cleared.
9. If gather is enabled (DMAC_CTLx.S_GATH_EN is enabled), program the
DMAC_SGRx register for channel x.
10. If scatter is enabled (DMAC_CTLx.D_SCAT_EN is enabled), program the
DMAC_DSRx register for channel x.
11. Clear any pending interrupts on the channel from the previous DMA transfer by writing to the Interrupt Clear registers: DMAC_ClearTfr, DMAC_ClearBlock,
DMAC_ClearSrcTran, DMAC_ClearDstTran, DMAC_ClearErr. Reading the Interrupt
Raw Status and Interrupt Status registers confirms that all interrupts have been
cleared.
12. Program the DMAC_CTLx, DMAC_CFGx registers according to Row 7 as shown in
Table 24-2 on page 267.
13. Program the DMAC_LLPx register with DMAC_LLPx(0), the pointer to the first Linked
List item.
14. Finally, enable the channel by writing a ‘1’ to the DMAC_ChEnReg.CH_EN bit. The
transfer is performed. Make sure that bit 0 of the DMAC_DmaCfgReg register is
enabled.
15. The DMAC fetches the first LLI from the location pointed to by DMAC_LLPx(0).
Note:
The LLI.DMAC_SARx, LLI.DMAC_DARx, LLI. DMAC_LLPx and LLI.DMAC_CTLx registers are
fetched. The LLI.DMAC_SARx register although fetched is not used.
16. Source and destination request single and burst DMAC transactions to transfer the
block of data (assuming non-memory peripherals). DMAC acknowledges at the com-
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AT91SAM9263 Preliminary
pletion of every transaction (burst and single) in the block and carry out the block
transfer.
17. The DMAC reloads the DMAC_SARx register from the initial value. Hardware sets
the block complete interrupt. The DMAC samples the row number as shown in Table
24-2 on page 267. If the DMAC is in Row 1 or 5, then the DMA transfer has completed. Hardware sets the transfer complete interrupt and disables the channel. You
can either respond to the Block Complete or Transfer Complete interrupts, or poll for
the Channel Enable (DMAC_ChEnReg.CH_EN) bit until it is cleared by hardware, to
detect when the transfer is complete. If the DMAC is not in Row 1 or 5 as shown in
Table 24-2 on page 267 the following steps are performed.
18. The DMA transfer proceeds as follows:
a. If interrupts are enabled (DMAC_CTLx.INT_EN = 1) and the block complete
interrupt is un-masked (DMAC_MaskBlock[x] = 1’b1, where x is the channel number) hardware sets the block complete interrupt when the block transfer has
completed. It then stalls until the block complete interrupt is cleared by software.
If the next block is to be the last block in the DMA transfer, then the block complete ISR (interrupt service routine) should clear the DMAC_CFGx.RELOAD_SR
source reload bit. This puts the DMAC into Row1 as shown in Table 24-2 on page
267. If the next block is not the last block in the DMA transfer, then the source
reload bit should remain enabled to keep the DMAC in Row 7 as shown in Table
24-2 on page 267.
b.
If interrupts are disabled (DMAC_CTLx.INT_EN = 0) or the block complete interrupt is masked (DMAC_MaskBlock[x] = 1’b0, where x is the channel number)
then hardware does not stall until it detects a write to the block complete interrupt
clear register but starts the next block transfer immediately. In this case, software
must clear the source reload bit, DMAC_CFGx.RELOAD_SR, to put the device
into Row 1 of Table 24-2 on page 267 before the last block of the DMA transfer
has completed.
19. The DMAC fetches the next LLI from memory location pointed to by the current
DMAC_LLPx register, and automatically reprograms the DMAC_DARx, DMAC_CTLx
and DMAC_LLPx channel registers. Note that the DMAC_SARx is not re-programmed as the reloaded value is used for the next DMA block transfer. If the next
block is the last block of the DMA transfer then the DMAC_CTLx and DMAC_LLPx
registers just fetched from the LLI should match Row 1 of Table 24-2 on page 267.
The DMA transfer might look like that shown in Figure 24-11 on page 280.
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6249B–ATARM–14-Dec-06
Figure 24-11. Multi-Block DMA Transfer with Source Address Auto-reloaded and Linked List Destination Address
Address of
Destination Layer
Address of
Source Layer
Block0
DAR(0)
Block1
DAR(1)
SAR
Block2
DAR(2)
BlockN
DAR(N)
Source Blocks
Destination Blocks
The DMA Transfer flow is shown in Figure on page 281
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AT91SAM9263 Preliminary
DMA Transfer Flow for Source Address Auto-reloaded and Linked List Destination Address
Channel Enabled by
software
LLI Fetch
Hardware reprograms
DARx, CTLx, LLPx
DMAC block transfer
Source/destination status fetch
Reload SARx
Block Complete interrupt
generated here
DMAC Transfer Complete
interrupt generated here
yes
Channel Disabled by
hardware
Is DMAC in
Row1 or Row5 of
DMAC State Machine Table?
no
CTLx.INT_EN=1
&&
MASKBLOCK[X]=1 ?
no
yes
Stall until block interrupt
Cleared by hardware
Multi-block Transfer with Source Address Auto-reloaded and Contiguous Destination Address (Row 3)
1. Read the Channel Enable register to choose a free (disabled) channel.
2. Clear any pending interrupts on the channel from the previous DMA transfer by writing to the Interrupt Clear registers: DMAC_ClearTfr, DMAC_ClearBlock,
DMAC_ClearSrcTran, DMAC_ClearDstTran, DMAC_ClearErr. Reading the Interrupt
Raw Status and Interrupt Status registers confirms that all interrupts have been
cleared.
3. Program the following channel registers:
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6249B–ATARM–14-Dec-06
a. Write the starting source address in the DMAC_SARx register for channel x.
b.
Write the starting destination address in the DMAC_DARx register for channel x.
c.
Program DMAC_CTLx and DMAC_CFGx according to Row 3 as shown in Table
24-2 on page 267. Program the DMAC_LLPx register with ‘0’.
d. Write the control information for the DMA transfer in the DMAC_CTLx register for
channel x. For example, in this register, you can program the following:
– i. Set up the transfer type (memory or non-memory peripheral for source and
destination) and flow control device by programming the TT_FC of the
DMAC_CTLx register.
– ii. Set up the transfer characteristics, such as:
– Transfer width for the source in the SRC_TR_WIDTH field.
– Transfer width for the destination in the DST_TR_WIDTH field.
– Source master layer in the SMS field where source resides.
– Destination master layer in the DMS field where destination resides.
– Incrementing/decrementing or fixed address for source in SINC field.
– Incrementing/decrementing or fixed address for destination in DINC field.
e. If gather is enabled (DMAC_CTLx.S_GATH_EN is enabled), program the
DMAC_SGRx register for channel x.
f.
If scatter is enabled (DMAC_CTLx.D_SCAT_EN), program the DMAC_DSRx register for channel x.
g. Write the channel configuration information into the DMAC_CFGx register for
channel x.
– i. Designate the handshaking interface type (hardware or software) for the source
and destination peripherals. This is not required for memory. This step requires
programming the HS_SEL_SRC/HS_SEL_DST bits, respectively. Writing a ‘0’
activates the hardware handshaking interface to handle source/destination
requests for the specific channel. Writing a ‘1’ activates the software handshaking
interface to handle source/destination requests.
– ii. If the hardware handshaking interface is activated for the source or destination
peripheral, assign handshaking interface to the source and destination peripheral.
This requires programming the SRC_PER and DEST_PER bits, respectively.
4. After the DMAC channel has been programmed, enable the channel by writing a ‘1’ to
the DMAC_ChEnReg.CH_EN bit. Make sure that bit 0 of the DMAC_DmaCfgReg
register is enabled.
5. Source and destination request single and burst DMAC transactions to transfer the
block of data (assuming non-memory peripherals). The DMAC acknowledges at the
completion of every transaction (burst and single) in the block and carries out the
block transfer.
6. When the block transfer has completed, the DMAC reloads the DMAC_SARx register. The DMAC_DARx register remains unchanged. Hardware sets the block
complete interrupt. The DMAC then samples the row number as shown in Table 24-2
on page 267. If the DMAC is in Row 1, then the DMA transfer has completed. Hardware sets the transfer complete interrupt and disables the channel. So you can either
respond to the Block Complete or Transfer Complete interrupts, or poll for the Channel Enable (DMAC_ChEnReg.CH_EN) bit until it is cleared by hardware, to detect
when the transfer is complete. If the DMAC is not in Row 1, the next step is
performed.
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7. The DMA transfer proceeds as follows:
a. If interrupts are enabled (DMAC_CTLx.INT_EN = 1) and the block complete
interrupt is un-masked (DMAC_MaskBlock[x] = 1’b1, where x is the channel number) hardware sets the block complete interrupt when the block transfer has
completed. It then stalls until the block complete interrupt is cleared by software.
If the next block is to be the last block in the DMA transfer, then the block complete ISR (interrupt service routine) should clear the source reload bit,
DMAC_CFGx.RELOAD_SR. This puts the DMAC into Row1 as shown in Table
24-2 on page 267. If the next block is not the last block in the DMA transfer then
the source reload bit should remain enabled to keep the DMAC in Row3 as
shown in Table 24-2 on page 267.
b.
If interrupts are disabled (DMAC_CTLx.INT_EN = 0) or the block complete interrupt is masked (DMAC_MaskBlock[x] = 1’b0, where x is the channel number)
then hardware does not stall until it detects a write to the block complete interrupt
clear register but starts the next block transfer immediately. In this case software
must clear the source reload bit, DMAC_CFGx.RELOAD_SR, to put the device
into ROW 1 of Table 24-2 on page 267 before the last block of the DMA transfer
has completed.
The transfer is similar to that shown in Figure 24-12 on page 283.
The DMA Transfer flow is shown in Figure 24-13 on page 284.
Figure 24-12. Multi-block Transfer with Source Address Auto-reloaded and Contiguous Destination Address
Address of
Destination Layer
Address of
Source Layer
Block2
DAR(2)
Block1
DAR(1)
Block0
SAR
DAR(0)
Source Blocks
Destination Blocks
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6249B–ATARM–14-Dec-06
Figure 24-13. DMA Transfer for Source Address Auto-reloaded and Contiguous Destination Address
Channel Enabled by
software
Block Transfer
Reload SARx, CTLx
Block Complete interrupt
generated here
DMAC Transfer Complete
interrupt generated here
yes
Channel Disabled by
hardware
Is DMAC in Row1 of
DMAC State Machine Table?
no
CTLx.INT_EN=1
&&
MASKBLOCK[x]=1?
no
yes
Stall until Block Complete
interrupt cleared by software
Multi-block DMA Transfer with Linked List for Source and Contiguous Destination Address (Row 8)
1. Read the Channel Enable register to choose a free (disabled) channel.
2. Set up the linked list in memory. Write the control information in the LLI. DMAC_CTLx
register location of the block descriptor for each LLI in memory for channel x. For
example, in the register, you can program the following:
a. Set up the transfer type (memory or non-memory peripheral for source and destination) and flow control device by programming the TT_FC of the DMAC_CTLx
register.
b.
Set up the transfer characteristics, such as:
– i. Transfer width for the source in the SRC_TR_WIDTH field.
– ii. Transfer width for the destination in the DST_TR_WIDTH field.
– iii. Source master layer in the SMS field where source resides.
– iv. Destination master layer in the DMS field where destination resides.
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– v. Incrementing/decrementing or fixed address for source in SINC field.
– vi. Incrementing/decrementing or fixed address for destination DINC field.
3. Write the starting destination address in the DMAC_DARx register for channel x.
Note:
The values in the LLI.DMAC_DARx register location of each Linked List Item (LLI) in memory,
although fetched during an LLI fetch, are not used.
4. Write the channel configuration information into the DMAC_CFGx register for channel
x.
a. Designate the handshaking interface type (hardware or software) for the source
and destination peripherals. This is not required for memory. This step requires
programming the HS_SEL_SRC/HS_SEL_DST bits, respectively. Writing a ‘0’
activates the hardware handshaking interface to handle source/destination
requests for the specific channel. Writing a ‘1’ activates the software handshaking
interface to handle source/destination requests.
b.
If the hardware handshaking interface is activated for the source or destination
peripheral, assign handshaking interface to the source and destination peripherals. This requires programming the SRC_PER and DEST_PER bits, respectively.
5. Make sure that all LLI.DMAC_CTLx register locations of the LLI (except the last) are
set as shown in Row 8 of Table 24-2 on page 267, while the LLI.DMAC_CTLx register of the last Linked List item must be set as described in Row 1 of Table 24-2.
Figure 24-5 on page 266 shows a Linked List example with two list items.
6. Make sure that the LLI.DMAC_LLPx register locations of all LLIs in memory (except
the last) are non-zero and point to the next Linked List Item.
7. Make sure that the LLI.DMAC_SARx register location of all LLIs in memory point to
the start source block address proceeding that LLI fetch.
8. Make sure that the LLI.DMAC_CTLx.DONE field of the LLI.DMAC_CTLx register
locations of all LLIs in memory is cleared.
9. If gather is enabled (DMAC_CTLx.S_GATH_EN is enabled), program the
DMAC_SGRx register for channel x.
10. If scatter is enabled (DMAC_CTLx.D_SCAT_EN is enabled), program the
DMAC_DSRx register for channel x.
11. Clear any pending interrupts on the channel from the previous DMA transfer by writing to the Interrupt Clear registers: DMAC_ClearTfr, DMAC_ClearBlock,
DMAC_ClearSrcTran, DMAC_ClearDstTran, DMAC_ClearErr. Reading the Interrupt
Raw Status and Interrupt Status registers confirms that all interrupts have been
cleared.
12. Program the DMAC_CTLx, DMAC_CFGx registers according to Row 8 as shown in
Table 24-2 on page 267
13. Program the DMAC_LLPx register with DMAC_LLPx(0), the pointer to the first Linked
List item.
14. Finally, enable the channel by writing a ‘1’ to the DMAC_ChEnReg.CH_EN bit. The
transfer is performed. Make sure that bit 0 of the DMAC_DmaCfgReg register is
enabled.
15. The DMAC fetches the first LLI from the location pointed to by DMAC_LLPx(0).
Note:
The LLI.DMAC_SARx, LLI.DMAC_DARx, LLI.DMAC_LLPx and LLI.DMAC_CTLx registers are
fetched. The LLI.DMAC_DARx register location of the LLI although fetched is not used. The
DMAC_DARx register in the DMAC remains unchanged.
16. Source and destination requests single and burst DMAC transactions to transfer the
block of data (assuming non-memory peripherals). The DMAC acknowledges at the
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6249B–ATARM–14-Dec-06
completion of every transaction (burst and single) in the block and carry out the block
transfer.
17. The DMAC does not wait for the block interrupt to be cleared, but continues and
fetches the next LLI from the memory location pointed to by current DMAC_LLPx register and automatically reprograms the DMAC_SARx, DMAC_CTLx and DMAC_LLPx
channel registers. The DMAC_DARx register is left unchanged. The DMA transfer
continues until the DMAC samples the DMAC_CTLx and DMAC_LLPx registers at
the end of a block transfer match that described in Row 1 of Table 24-2 on page 267.
The DMAC then knows that the previous block transferred was the last block in the
DMA transfer.
The DMAC transfer might look like that shown in Figure 24-14 on page 286 Note that the destination address is decrementing.
Figure 24-14. DMA Transfer with Linked List Source Address and Contiguous Destination Address
Address of
Destination Layer
Address of
Source Layer
Block 2
SAR(2)
Block 2
DAR(2)
Block 1
Block 1
SAR(1)
DAR(1)
Block 0
Block 0
DAR(0)
SAR(0)
Source Blocks
Destination Blocks
The DMA transfer flow is shown in Figure 24-15 on page 287.
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AT91SAM9263 Preliminary
Figure 24-15. DMA Transfer Flow for Source Address Auto-reloaded and Contiguous Destination Address
Channel Enabled by
software
LLI Fetch
Hardware reprograms
SARx, CTLx, LLPx
DMAC block transfer
Source/destination
status fetch
Block Complete interrupt
generated here
Is DMAC in
Row 1 of Table 4 ?
DMAC Transfer Complete
interrupt generated here
no
yes
Channel Disabled by
hardware
24.3.6
Disabling a Channel Prior to Transfer Completion
Under normal operation, software enables a channel by writing a ‘1’ to the Channel Enable
Register, DMAC_ChEnReg.CH_EN, and hardware disables a channel on transfer completion
by clearing the DMAC_ChEnReg.CH_EN register bit.
The recommended way for software to disable a channel without losing data is to use the
CH_SUSP bit in conjunction with the FIFO_EMPTY bit in the Channel Configuration Register
(DMAC_CFGx) register.
1. If software wishes to disable a channel prior to the DMA transfer completion, then it
can set the DMAC_CFGx.CH_SUSP bit to tell the DMAC to halt all transfers from the
source peripheral. Therefore, the channel FIFO receives no new data.
2. Software can now poll the DMAC_CFGx.FIFO_EMPTY bit until it indicates that the
channel FIFO is empty.
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6249B–ATARM–14-Dec-06
3. The DMAC_ChEnReg.CH_EN bit can then be cleared by software once the channel
FIFO is empty.
When DMAC_CTLx.SRC_TR_WIDTH is less than DMAC_CTLx.DST_TR_WIDTH and the
DMAC_CFGx.CH_SUSP bit is high, the DMAC_CFGx.FIFO_EMPTY is asserted once the
contents of the FIFO do not permit a single word of DMAC_CTLx.DST_TR_WIDTH to be
formed. However, there may still be data in the channel FIFO but not enough to form a single
transfer of DMAC_CTLx.DST_TR_WIDTH width. In this configuration, once the channel is disabled, the remaining data in the channel FIFO are not transferred to the destination peripheral.
It is permitted to remove the channel from the suspension state by writing a ‘0’ to the
DMAC_CFGx.CH_SUSP register. The DMA transfer completes in the normal manner.
Note:
24.3.6.1
If a channel is disabled by software, an active single or burst transaction is not guaranteed to
receive an acknowledgement.
Abnormal Transfer Termination
A DMAC DMA transfer may be terminated abruptly by software by clearing the channel enable
bit, DMAC_ChEnReg.CH_EN. This does not mean that the channel is disabled immediately
after the DMAC_ChEnReg.CH_EN bit is cleared over the AHB slave interface. Consider this
as a request to disable the channel. The DMAC_ChEnReg.CH_EN must be polled and then it
must be confirmed that the channel is disabled by reading back 0. A case where the channel is
not be disabled after a channel disable request is where either the source or destination has
received a split or retry response. The DMAC must keep re-attempting the transfer to the system HADDR that originally received the split or retry response until an OKAY response is
returned. To do otherwise is an AMBA protocol violation.
Software may terminate all channels abruptly by clearing the global enable bit in the DMAC
Configuration Register (DMAC_DmaCfgReg[0]). Again, this does not mean that all channels
are disabled immediately after the DMAC_DmaCfgReg[0] is cleared over the AHB slave interface. Consider this as a request to disable all channels. The DMAC_ChEnReg must be polled
and then it must be confirmed that all channels are disabled by reading back ‘0’.
288
Note:
If the channel enable bit is cleared while there is data in the channel FIFO, this data is not sent
to the destination peripheral and is not present when the channel is re-enabled. For read sensitive source peripherals such as a source FIFO this data is therefore lost. When the source is not
a read sensitive device (i.e., memory), disabling a channel without waiting for the channel FIFO
to empty may be acceptable as the data is available from the source peripheral upon request
and is not lost.
Note:
If a channel is disabled by software, an active single or burst transaction is not guaranteed to
receive an acknowledgement.
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AT91SAM9263 Preliminary
24.4
DMA Controller (DMAC) User Interface
Table 24-3.
Offset
DMA Controller (DMAC) User Interface
Register
Register Name
0x0
Channel 0 Source Address Register
DMAC_SAR0
0x4
Reserved
0x8
Channel 0 Destination Address Register
0xC
Reserved
0x10
Channel 0 Linked List Pointer Register
0x14
Reserved
0x18
Channel 0 Control Register Low
DMAC_CTL0L
Read/Write
0x1C
Channel 0 Control Register High
DMAC_CTL0H
Read/Write
0x20 - 0x3C
Access
Reset Value
Read/Write
0x0
-
DMAC_DAR0
Read/Write
0x0
-
DMAC_LLP0
Read/Write
0x0
-
Reserved
0x40
Channel 0 Configuration Register Low
DMAC_CFG0L
Read/Write
0x00000c00
0x44
Channel 0 Configuration Register High
DMAC_CFG0H
Read/Write
0x00000004
0x48
Channel 0 Source Gather Register
DMAC_SGR0
Read/Write
0x0
0x4C
Reserved
0x50
Channel 0 Destination Scatter Register
DMAC_DSR0
Read/Write
0x0
0x54
Reserved
0x58
Channel 1 Source Address Register
DMAC_SAR1
Read/Write
0x0
0x5C
Reserved
0x60
Channel 1 Destination Address Register
DMAC_DAR1
Read/Write
0x0
0x64
Reserved
0x68
Channel 1 Linked List Pointer Register
DMAC_LLP1
Read/Write
0x0
0x7C
Reserved
0x70
Channel 1 Control Register Low
DMAC_CTL1L
Read/Write
0x74
Channel 1 Control Register High
DMAC_CTL1H
Read/Write
0x78 - 0x94
Reserved
0x98
Channel 1 Configuration Register Low
DMAC_CFG1L
Read/Write
0x00000c20
0x9C
Channel 1 Configuration Register High
DMAC_CFG1H
Read/Write
0x00000004
0xa0
Channel 1 Source Gather Register
DMAC_SGR1
Read/Write
0x0
0xa4
Reserved
0xa8
Channel 1 Destination Scatter Register
DMAC_DSR1
Read/Write
0x0
DMAC_RawTfr
Read
0x0
DMAC_RawBlock
Read
0x0
DMAC_RawSrcTran
Read
0x0
0xac..0x2bc
Reserved
0x2c0
Raw Status for IntTfr Interrupt
0x2c4
Reserved
0x2c8
Raw Status for IntBlock Interrupt
0x2cc
Reserved
0x2d0
Raw Status for IntSrcTran Interrupt
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Table 24-3.
290
DMA Controller (DMAC) User Interface
Offset
Register
0x2d4
Reserved
0x2d8
Raw Status for IntDstTran Interrupt
0x2dc
Reserved
0x2e0
Raw Status for IntErr Interrupt
0x2e4
Reserved
0x2e8
Status for IntTfr Interrupt
0x2ec
Reserved
0x2f0
Status for IntBlock Interrupt
0x2f4
Reserved
0x2f8
Status for IntSrcTran Interrupt
0x2fc
Reserved
0x300
Status for IntDstTran Interrupt
0x304
Reserved
0x308
Status for IntErr Interrupt
0x30c
Reserved
0x310
Mask for IntTfr Interrupt
0x314
Reserved
0x318
Mask for IntBlock Interrupt
0x31c
Reserved
0x320
Mask for IntSrcTran Interrupt
0x324
Reserved
0x328
Mask for IntDstTran Interrupt
0x32c
Reserved
0x330
Mask for IntErr Interrupt
0x334
Reserved
0x338
Clear for IntTfr Interrupt
0x33c
Reserved
0x340
Clear for IntBlock Interrupt
0x344
Reserved
0x348
Clear for IntSrcTran Interrupt
0x34c
Reserved
0x350
Clear for IntDstTran Interrupt
0x354
Reserved
0x358
Clear for IntErr Interrupt
0x35c
Reserved
0x360
Status for each interrupt type
Register Name
Access
Reset Value
DMAC_RawDstTran
Read
0x0
DMAC_RawErr
Read
0x0
DMAC_StatusTfr
Read
0x0
DMAC_StatusBlock
Read
0x0
DMAC_StatusSrcTran
Read
0x0
DMAC_StatusDstTran
Read
0x0
DMAC_StatusErr
Read
0x0
DMAC_MaskTfr
Read/Write
0x0
DMAC_MaskBlock
Read/Write
0x0
DMAC_MaskSrcTran
Read/Write
0x0
DMAC_MaskDstTran
Read/Write
0x0
DMAC_MaskErr
Read/Write
0x0
DMAC_ClearTfr
Write
0x0
DMAC_ClearBlock
Write
0x0
DMAC_ClearSrcTran
Write
0x0
DMAC_ClearDstTran
Write
0x0
DMAC_ClearErr
Write
0x0
DMAC_StatusInt
Read
0x0
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AT91SAM9263 Preliminary
Table 24-3.
DMA Controller (DMAC) User Interface
Offset
Register
0x364
Reserved
0x368
Source Software Transaction Request Register
0x36c
Reserved
0x370
Destination Software Transaction Request Register
0x374
Reserved
0x378
Single Source Transaction Request Register
0x37c
Reserved
0x380
Single Destination Transaction Request Register
0x384
Reserved
0x388
Last Source Transaction Request Register
0x38c
Reserved
0x390
Last Destination Transaction Request Register
0x394
Reserved
0x398
DMA Configuration Register
0x39c
Reserved
0x3a0
Channel Enable Register
0x3a4
Reserved
0x3a8
DMA ID Register
0x3ac
Reserved
0x3b0
DMA Test Register
0x3b4
Reserved
0x3b8
DMA Version ID Register
0x3b8
Reserved
Register Name
Access
Reset Value
DMAC_ReqSrcReg
Read/Write
0x0
DMAC_ReqDstReg
Read/Write
0x0
DMAC_SglReqSrcReg
Read/Write
0x0
DMAC_SglReqDstReg
Read/Write
0x0
DMAC_LstSrcReg
Read/Write
0x0
DMAC_LstDstReg
Read/Write
0x0
DMAC_DmaCfgReg
Read/Write
0x0
DMAC_ChEnReg
Read/Write
0x0
Read
0x203a125a
DMAC_IdReg
DMAC_DmaTestReg
Read/Write
Read
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24.4.1
Channel x Source Address Register
Name: DMAC_SARx
Access: Read/Write
Reset: 0x0
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
SADD
23
22
21
20
15
14
13
12
SADD
SADD
7
6
5
4
SADD
The address offset for each channel is: [x *0x58]
For example, SAR0: 0x000, SAR1: 0x058, etc.
• SADD: Source Address of DMA transfer
The starting AMBA source address is programmed by software before the DMA channel is enabled or by a LLI update
before the start of the DMA transfer. As the DMA transfer is in progress, this register is updated to reflect the source
address of the current AMBA transfer.
Updated after each source AMBA transfer. The SINC field in the DMAC_CTLx register determines whether the address
increments, decrements, or is left unchanged on every source AMBA transfer throughout the block transfer.
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24.4.2
Channel x Destination Address Register
Name: DMAC_DARx
Access: Read/Write
Reset: 0x0
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
DADD
23
22
21
20
15
14
13
12
DADD
DADD
7
6
5
4
DADD
The address offset for each channel is: 0x08+[x * 0x58]
For example, DAR0: 0x008, DAR1: 0x060, etc.
• DADD: Destination Address of DMA transfer
The starting AMBA destination address is programmed by software before the DMA channel is enabled or by a LLI update
before the start of the DMA transfer. As the DMA transfer is in progress, this register is updated to reflect the destination
address of the current AMBA transfer.
Updated after each destination AMBA transfer. The DINC field in the DMAC_CTLx register determines whether the
address increments, decrements or is left unchanged on every destination AMBA transfer throughout the block transfer.
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24.4.3
Linked List Pointer Register for Channel x
Name: DMAC_LLPx
Access: Read/Write
Reset: 0x0
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
0
0
LOC
23
22
21
20
15
14
13
12
LOC
LOC
7
6
5
4
LOC
The address offset for each channel is: 0x10+[x * 0x58]
For example, LLP0: 0x010, LLP1: 0x068, etc.
• LOC: Address of the next LLI
Starting address in memory of next LLI if block chaining is enabled. Note that the two LSBs of the starting address are not
stored because the address is assumed to be aligned to a 32-bit boundary.
The user need to program this register to point to the first Linked List Item (LLI) in memory prior to enabling the channel if
block chaining is enabled.
The LLP register has two functions:
1. The logical result of the equation LLP.LOC != 0 is used to set up the type of DMA transfer (single or multi-block).
If LLP.LOC is set to 0x0, then transfers using linked lists are NOT enabled. This register must be programmed prior to
enabling the channel in order to set up the transfer type.
It (LLP.LOC != 0) contains the pointer to the next Linked Listed Item for block chaining using linked lists.
2. The DMAC_LLPx register is also used to point to the address where write back of the control and source/destination status information occurs after block completion.
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24.4.4
Control Register for Channel x Low
Name: DMAC_CTLxL
Access: Read/Write
Reset: 0x0
31
–
23
DMS
15
SRC_MSIZE
7
DINC
30
–
22
29
–
21
TT_FC
13
14
6
5
SRC_TR_WIDTH
28
LLP_S_EN
20
12
DEST_MSIZE
4
27
LLP_D_EN
19
11
3
26
25
SMS
18
17
D_SCAT_EN
S_GATH_EN
10
9
SINC
2
1
DST_TR_WIDTH
24
DMS
16
SRC_MSIZE
8
DINC
0
INT_EN
The address offset for each channel is: 0x18+[x * 0x58]
For example, CTL0: 0x018, CTL1: 0x070, etc.
This register contains fields that control the DMA transfer. The DMAC_CTLxL register is part of the block descriptor (linked
list item) when block chaining is enabled. It can be varied on a block-by-block basis within a DMA transfer when block
chaining is enabled.
• INT_EN: Interrupt Enable Bit
If set, then all five interrupt generating sources are enabled.
• DST_TR_WIDTH: Destination Transfer Width
• SRC_TR_WIDTH: Source Transfer Width
SRC_TR_WIDTH/DST_TR_WIDTH
Size (bits)
000
8
001
16
010
32
Other
Reserved
• DINC: Destination Address Increment
Indicates whether to increment or decrement the destination address on every destination AMBA transfer. If your device is
writing data to a destination peripheral FIFO with a fixed address, then set this field to “No change”.
00 = Increment
01 = Decrement
1x = No change
• SINC: Source Address Increment
Indicates whether to increment or decrement the source address on every source AMBA transfer. If your device is fetching
data from a source peripheral FIFO with a fixed address, then set this field to “No change”.
00 = Increment
01 = Decrement
1x = No change
• DEST_MSIZE: Destination Burst Transaction Length
Number of data items, each of width DMAC_CTLx.DST_TR_WIDTH, to be written to the destination every time a destination burst transaction request is made from either the corresponding hardware or software handshaking interface.
• SRC_MSIZE: Source Burst Transaction Length
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Number of data items, each of width DMAC_CTLx.SRC_TR_WIDTH, to be read from the source every time a source burst
transaction request is made from either the corresponding hardware or software handshaking interface.
• S_GATH_EN: Source Gather Enable Bit
0 = Gather is disabled.
1 = Gather is enabled.
Gather on the source side is only applicable when the DMAC_CTLx.SINC bit indicates an incrementing or decrementing
address control.
• D_SCAT_EN: Destination Scatter Enable Bit
0 = Scatter is disabled.
1 = Scatter is enabled.
Scatter on the destination side is only applicable when the DMAC_CTLx.DINC bit indicates an incrementing or decrementing address control.
• TT_FC: Transfer Type and Flow Control
The following transfer types are supported.
• Memory to Memory
• Memory to Peripheral
• Peripheral to Memory
Flow Control can be assigned to the DMAC, the source peripheral, or the destination peripheral.
TT_FC
Transfer Type
Flow Controller
000
Memory to Memory
DMAC
001
Memory to Peripheral
DMAC
010
Peripheral to Memory
DMAC
011
Peripheral to Peripheral
DMAC
100
Peripheral to Memory
Peripheral
101
Peripheral to Peripheral
Source Peripheral
110
Memory to Peripheral
Peripheral
111
Peripheral to Peripheral
Destination Peripheral
• DMS: Destination Master Select
Identifies the Master Interface layer where the destination device (peripheral or memory) resides.
00 = AHB master 1
01 = Reserved
10 = Reserved
11 = Reserved
• SMS: Source Master Select
Identifies the Master Interface layer where the source device (peripheral or memory) is accessed from.
00 = AHB master 1
01 = Reserved
10 = Reserved
11 = Reserved
• LLP_D_EN
Block chaining is only enabled on the destination side if the LLP_D_EN field is high and DMAC_LLPx.LOC is non-zero.
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• LLP_S_EN
Block chaining is only enabled on the source side if the LLP_S_EN field is high and DMAC_LLPx.LOC is non-zero.
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24.4.5
Control Register for Channel x High
Name: DMAC_CTLxH
Access: Read/Write
Reset: 0x0
31
–
23
30
–
22
29
–
21
28
–
20
27
–
19
26
–
18
25
–
17
24
–
16
15
–
7
–
14
–
6
–
13
–
5
–
12
DONE
4
11
–
3
10
–
2
BLOCK_TS
9
–
1
8
–
0
• BLOCK_TS: Block Transfer Size
When the DMAC is flow controller, this field is written by the user before the channel is enabled to indicate the block size.
The number programmed into BLOCK_TS indicates the total number of single transactions to perform for every block
transfer. The width of the single transaction is determined by DMAC_CTLx.SRC_TR_WIDTH.
• DONE: Done Bit
Software can poll the LLI DMAC_CTLx.DONE bit to see when a block transfer is complete. The LLI DMAC_CTLx.DONE bit
should be cleared when the linked lists are setup in memory prior to enabling the channel.
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24.4.6
Configuration Register for Channel x Low
Name: DMAC_CFGxL
Access: Read/Write
Reset: 0x0
31
RELOAD_DS
23
30
29
28
RELOAD_SR
22
21
20
MAX_ABRST
15
14
13
12
LOCK_B_L
LOCK_CH_L
7
6
5
4
CH_PRIOR
–
27
26
25
24
18
DS_HS_POL
10
HS_SEL_DS
2
–
17
LOCK_B
9
FIFO_EMPT
1
–
16
LOCK_CH
8
CH_SUSP
0
–
MAX_ABRST
19
SR_HS_POL
11
HS_SEL_SR
3
–
The address offset for each channel is: 0x40+[x * 0x58]
For example, CFG0: 0x040, CFG1: 0x098, etc.
• CH_PRIOR: Channel priority
A priority of 7 is the highest priority, and 0 is the lowest. This field must be programmed within the following range [0, x – 1]
A programmed value outside this range causes erroneous behavior.
• CH_SUSP: Channel Suspend
Suspends all DMA data transfers from the source until this bit is cleared. There is no guarantee that the current transaction
will complete. Can also be used in conjunction with DMAC_CFGx.FIFO_EMPTY to cleanly disable a channel without losing
any data.
0 = Not Suspended.
1 = Suspend. Suspend DMA transfer from the source.
• FIFO_EMPTY
Indicates if there is data left in the channel's FIFO. Can be used in conjunction with DMAC_CFGx.CH_SUSP to cleanly disable a channel.
1 = Channel's FIFO empty
0 = Channel's FIFO not empty
• HS_SEL_DST: Destination Software or Hardware Handshaking Select
This register selects which of the handshaking interfaces, hardware or software, is active for destination requests on this
channel.
0 = Hardware handshaking interface. Software-initiated transaction requests are ignored.
1 = Software handshaking interface. Hardware Initiated transaction requests are ignored.
If the destination peripheral is memory, then this bit is ignored.
• HS_SEL_SRC: Source Software or Hardware Handshaking Select
This register selects which of the handshaking interfaces, hardware or software, is active for source requests on this
channel.
0 = Hardware handshaking interface. Software-initiated transaction requests are ignored.
1 = Software handshaking interface. Hardware-initiated transaction requests are ignored.
If the source peripheral is memory, then this bit is ignored.
• LOCK_CH_L: Channel Lock Level
Indicates the duration over which DMAC_CFGx.LOCK_CH bit applies.
00 = Over complete DMA transfer
01 = Over complete DMA block transfer
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1x = Over complete DMA transaction
• LOCK_B_L: Bus Lock Level
Indicates the duration over which DMAC_CFGx.LOCK_B bit applies.
00 = Over complete DMA transfer
01 = Over complete DMA block transfer
1x = Over complete DMA transaction
• LOCK_CH: Channel Lock Bit
When the channel is granted control of the master bus interface and if the DMAC_CFGx.LOCK_CH bit is asserted, then no
other channels are granted control of the master bus interface for the duration specified in DMAC_CFGx.LOCK_CH_L.
Indicates to the master bus interface arbiter that this channel wants exclusive access to the master bus interface for the
duration specified in DMAC_CFGx.LOCK_CH_L.
• LOCK_B: Bus Lock Bit
When active, the AMBA bus master signal hlock is asserted for the duration specified in DMAC_CFGx.LOCK_B_L.
• DS_HS_POL: Destination Handshaking Interface Polarity
0 = Active high
1 = Active low
• SR_HS_POL: Source Handshaking Interface Polarity
0 = Active high
1 = Active low
• MAX_ABRST: Maximum AMBA Burst Length
Maximum AMBA burst length that is used for DMA transfers on this channel. A value of ‘0’ indicates that software is not limiting the maximum AMBA burst length for DMA transfers on this channel.
• RELOAD_SR: Automatic Source Reload
The DMAC_SARx register can be automatically reloaded from its initial value at the end of every block for multi-block transfers. A new block transfer is then initiated.
• RELOAD_DS: Automatic Destination Reload
The DMAC_DARx register can be automatically reloaded from its initial value at the end of every block for multi-block
transfers. A new block transfer is then initiated.
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24.4.7
Configuration Register for Channel x High
Name: DMAC_CFGxH
Access: Read/Write
Reset: 0x0
31
–
23
–
15
–
7
SRC_PER
30
–
22
–
14
29
–
21
–
13
6
–
5
–
28
–
20
–
12
27
–
19
–
11
26
–
18
–
10
4
3
PROTCTL
2
DEST_PER
25
–
17
–
9
SRC_PER
1
FIFO_MODE
24
–
16
–
8
0
FCMODE
• FCMODE: Flow Control Mode
Determines when source transaction requests are serviced when the Destination Peripheral is the flow controller.
0 = Source transaction requests are serviced when they occur. Data pre-fetching is enabled.
1 = Source transaction requests are not serviced until a destination transaction request occurs. In this mode the amount of
data transferred from the source is limited such that it is guaranteed to be transferred to the destination prior to block termination by the destination. Data pre-fetching is disabled.
• FIFO_MODE: R/W 0x0 FIFO Mode Select
Determines how much space or data needs to be available in the FIFO before a burst transaction request is serviced.
0 = Space/data available for single AMBA transfer of the specified transfer width.
1 = Space/data available is greater than or equal to half the FIFO depth for destination transfers and less than half the FIFO
depth for source transfers. The exceptions are at the end of a burst transaction request or at the end of a block transfer.
• PROTCTL: Protection Control
bits used to drive the AMBA HPROT[3:1] bus. The AMBA Specification recommends that the default value of HPROT indicates a non-cached, nonbuffered, privileged data access. The reset value is used to indicate such an access.
• HPROT[0] is tied high as all transfers are data accesses as there are no opcode fetches. There is a one-to-one mapping
of these register bits to the HPROT[3:1] master interface signals. SRC_PER: Source Hardware Handshaking
Interface
Assigns a hardware handshaking interface (0 - DMAH_NUM_HS_INT-1) to the source of channel x if the
DMAC_CFGx.HS_SEL_SRC field is 0. Otherwise, this field is ignored. The channel can then communicate with the source
peripheral connected to that interface via the assigned hardware handshaking interface.
For correct DMAC operation, only one peripheral (source or destination) should be assigned to the same handshaking
interface.
• DEST_PER: Destination Hardware Handshaking Interface
Assigns a hardware handshaking interface (0 - DMAH_NUM_HS_INT-1) to the destination of channel x if the
DMAC_CFGx.HS_SEL_DST field is 0. Otherwise, this field is ignored. The channel can then communicate with the destination peripheral connected to that interface via the assigned hardware handshaking interface.
For correct DMA operation, only one peripheral (source or destination) should be assigned to the same handshaking
interface.
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24.4.8
Source Gather Register for Channel x
Name: DMAC_SGRx
Access: Read/Write
Reset: 0x0
31
–
23
30
–
22
15
14
29
–
21
28
–
20
27
–
19
26
–
18
25
–
17
24
–
16
13
12
11
10
9
8
3
2
1
0
SGC
SGI
SGI
7
6
5
4
SGI
The address offset for each channel is: 0x48+[x * 0x58]
For example, SGR0: 0x048, SGR1: 0x0a0, etc.
The DMAC_CTLx.SINC field controls whether the address increments or decrements. When the DMAC_CTLx.SINC field
indicates a fixed-address control, then the address remains constant throughout the transfer and the DMAC_SGRx register
is ignored.
• SGI: Source Gather Interval
Source gather count field specifies the number of contiguous source transfers of DMAC_CTLx.SRC_TR_WIDTH between
successive gather intervals. This is defined as a gather boundary.
• SGC: Source gather count
Source gather interval field (DMAC_SGRx.SGI) – specifies the source address increment/decrement in multiples of
DMAC_CTLx.SRC_TR_WIDTH on a gather boundary when gather mode is enabled for the source transfer.
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24.4.9
Destination Scatter Register for Channel x
Name: DMAC_DSRx
Access: Read/Write
Reset: 0x0
31
–
23
30
–
22
15
14
29
–
21
28
–
20
27
–
19
26
–
18
25
–
17
24
–
16
13
12
11
10
9
8
3
2
1
0
DSC
DSI
DSI
7
6
5
4
DSI
The address offset for each channel is: 0x50+[x * 0x58]
For example, DSR0: 0x050, DSR1: 0x0a8, etc.
The DMAC_CTLx.DINC field controls whether the address increments or decrements. When the DMAC_CTLx.DINC field
indicates a fixed address control then the address remains constant throughout the transfer and the DMAC_DSRx register
is ignored.
• DSI: Destination Scatter Interval
Destination scatter interval field (DMAC_DSRx.DSI) – specifies the destination address increment/decrement in multiples
of DMAC_CTLx.DST_TR_WIDTH on a scatter boundary when scatter mode is enabled for the destination transfer.
• DSC: Destination Scatter count
Destination scatter count field (DMAC_DSRx.DSC) – specifies the number of contiguous destination transfers of
DMAC_CTLx.DST_TR_WIDTH between successive scatter boundaries.
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6249B–ATARM–14-Dec-06
24.4.10
Interrupt Registers
The following sections describe the registers pertaining to interrupts, their status, and how to clear them. For each channel,
there are five types of interrupt sources:
• IntTfr: DMA Transfer Complete Interrupt
This interrupt is generated on DMA transfer completion to the destination peripheral.
• IntBlock: Block Transfer Complete Interrupt
This interrupt is generated on DMA block transfer completion to the destination peripheral.
• IntSrcTran: Source Transaction Complete Interrupt
This interrupt is generated after completion of the last AMBA transfer of the requested single/burst transaction from the
handshaking interface on the source side.
If the source for a channel is memory, then that channel never generates a IntSrcTran interrupt and hence the corresponding bit in this field is not set.
• IntDstTran: Destination Transaction Complete Interrupt
This interrupt is generated after completion of the last AMBA transfer of the requested single/burst transaction from the
handshaking interface on the destination side.
If the destination for a channel is memory, then that channel never generates the IntDstTran interrupt and hence the corresponding bit in this field is not set.
• IntErr: Error Interrupt
This interrupt is generated when an ERROR response is received from an AHB slave on the HRESP bus during a DMA
transfer. In addition, the DMA transfer is cancelled and the channel is disabled.
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24.4.11
Interrupt Raw Status Registers
Name: DMAC_RawTfr, DMAC_RawBlock, DMAC_RawSrcTran, DMAC_RawDstTran, DMAC_RawErr
Access: Read
Reset: 0x0
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
–
28
–
20
–
12
–
4
–
27
–
19
–
11
–
3
–
26
–
18
–
10
–
2
–
25
–
17
–
9
–
1
RAW1
24
–
16
–
8
–
0
RAW0
The address offset are
DMAC_RawTfr – 0x2c0
DMAC_RawBlock – 0x2c8
DMAC_RawSrcTran – 0x2d0
DMAC_RawDstTran – 0x2d8
DMAC_RawErr – 0x2e0
• RAW[1:0]: Raw interrupt for each channel
Interrupt events are stored in these Raw Interrupt Status Registers before masking: DMAC_RawTfr, DMAC_RawBlock,
DMAC_RawSrcTran, DMAC_RawDstTran, DMAC_RawErr. Each Raw Interrupt Status register has a bit allocated per
channel, for example, DMAC_RawTfr[2] is Channel 2’s raw transfer complete interrupt. Each bit in these registers is
cleared by writing a 1 to the corresponding location in the DMAC_ClearTfr, DMAC_ClearBlock, DMAC_ClearSrcTran,
DMAC_ClearDstTran, DMAC_ClearErr registers.
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6249B–ATARM–14-Dec-06
24.4.12
Interrupt Status Registers
Name: DMAC_StatusTfr, DMAC_StatusBlock, DMAC_StatusSrcTran, DMAC_StatusDstTran, DMAC_StatusErr
Access: Read
Reset: 0x0
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
–
28
–
20
–
12
–
4
–
27
–
19
–
11
–
3
–
26
–
18
–
10
–
2
–
25
–
17
–
9
–
1
STATUS1
24
–
16
–
8
–
0
STATUS0
The address offset are
DMAC_StatusTfr: 0x2e8
DMAC_StatusBlock: 0x2f0
DMAC_StatusSrcTran: 0x2f8
DMAC_StatusDstTran: 0x300
DMAC_StatusErr: 0x308
• STATUS[1:0]
All interrupt events from all channels are stored in these Interrupt Status Registers after masking: DMAC_StatusTfr,
DMAC_StatusBlock, DMAC_StatusSrcTran, DMAC_StatusDstTran, DMAC_StatusErr. Each Interrupt Status register has a
bit allocated per channel, for example, DMAC_StatusTfr[2] is Channel 2’s status transfer complete interrupt.The contents
of these registers are used to generate the interrupt signals leaving the DMAC.
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24.4.13
Interrupt Status Registers
Name: DMAC_MaskTfr, DMAC_MaskBlock, DMAC_MaskSrcTran, DMAC_MaskDstTran, DMAC_MaskErr
Access: Read/Write
Reset: 0x0
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
–
28
–
20
–
12
–
4
–
27
–
19
–
11
–
3
–
26
–
18
–
10
–
2
–
25
–
17
–
9
INT_M_WE1
1
INT_MASK1
24
–
16
–
8
INT_M_WE0
0
INT_MASK0
The address offset are
DMAC_MaskTfr: 0x310
DMAC_MaskBlock: 0x318
DMAC_MaskSrcTran: 0x320
DMAC_MaskDstTran: 0x328
DMAC_MaskErr: 0x330
The contents of the Raw Status Registers are masked with the contents of the Mask Registers: DMAC_MaskTfr,
DMAC_MaskBlock, DMAC_MaskSrcTran, DMAC_MaskDstTran, DMAC_MaskErr. Each Interrupt Mask register has a bit
allocated per channel, for example, DMAC_MaskTfr[2] is the mask bit for Channel 2’s transfer complete interrupt.
A channel’s INT_MASK bit is only written if the corresponding mask write enable bit in the INT_MASK_WE field is asserted
on the same AMBA write transfer. This allows software to set a mask bit without performing a read-modified write
operation.
For example, writing hex 01x1 to the DMAC_MaskTfr register writes a 1 into DMAC_MaskTfr[0], while DMAC_MaskTfr[7:1]
remains unchanged. Writing hex 00xx leaves DMAC_MaskTfr[7:0] unchanged.
Writing a 1 to any bit in these registers unmasks the corresponding interrupt, thus allowing the DMAC to set the appropriate
bit in the Status Registers.
• INT_MASK[1:0]: Interrupt Mask
0 = Masked
1 = Unmasked
• INT_M_WE[9:8]: Interrupt Mask Write Enable
0 = Write disabled
1 = Write enabled
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24.4.14
Interrupt Clear Registers
Name: DMAC_ClearTfr, DMAC_ClearBlock, DMAC_ClearSrcTran, DMAC_ClearDstTran,DMAC_ClearErr
Access: Write
Reset: 0x0
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
–
28
–
20
–
12
–
4
–
27
–
19
–
11
–
3
–
26
–
18
–
10
–
2
–
25
–
17
–
9
–
1
CLEAR1
24
–
16
–
8
–
0
CLEAR0
The address offset are
DMAC_ClearTfr: 0x338
DMAC_ClearBlock: 0x340
DMAC_ClearSrcTran: 0x348
DMAC_ClearDstTran: 0x350
DMAC_ClearErr: 0x358
• CLEAR[1:0]: Interrupt Clear
0 = No effect
1 = Clear interrupt
Each bit in the Raw Status and Status registers is cleared on the same cycle by writing a 1 to the corresponding location in
the Clear registers: DMAC_ClearTfr, DMAC_ClearBlock, DMAC_ClearSrcTran, DMAC_ClearDstTran, DMAC_ClearErr.
Each Interrupt Clear register has a bit allocated per channel, for example, DMAC_ClearTfr[2] is the clear bit for Channel 2’s
transfer complete interrupt. Writing a 0 has no effect. These registers are not readable.
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24.4.15
Combined Interrupt Status Registers
Name: DMAC_StatusInt
Access: Read
Reset: 0x0
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
–
28
–
20
–
12
–
4
ERR
27
–
19
–
11
–
3
DSTT
26
–
18
–
10
–
2
SRCT
25
–
17
–
9
–
1
BLOCK
24
–
16
–
8
–
0
TFR
The contents of each of the five Status Registers (DMAC_StatusTfr, DMAC_StatusBlock, DMAC_StatusSrcTran,
DMAC_StatusDstTran, DMAC_StatusErr) is OR’d to produce a single bit per interrupt type in the Combined Status Register (DMAC_StatusInt).
• TFR
OR of the contents of DMAC_StatusTfr Register.
• BLOCK
OR of the contents of DMAC_StatusBlock Register.
• SRCT
OR of the contents of DMAC_StatusSrcTran Register.
• DSTT
OR of the contents of DMAC_StatusDstTran Register.
• ERR
OR of the contents of DMAC_StatusErr Register.
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24.4.16
Source Software Transaction Request Register
Name: DMAC_ReqSrcReg
Access: Read/write
Reset: 0x0
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
–
28
–
20
–
12
–
4
–
27
–
19
–
11
–
3
–
26
–
18
–
10
–
2
–
25
–
17
–
9
REQ_WE1
1
SRC_REQ1
24
–
16
–
8
REQ_WE0
0
SRC_REQ0
A bit is assigned for each channel in this register. DMAC_ReqSrcReg[n] is ignored when software handshaking is not
enabled for the source of channel n.
A channel SRC_REQ bit is written only if the corresponding channel write enable bit in the REQ_WE field is asserted on
the same AMBA write transfer.
For example, writing 0x101 writes a 1 into DMAC_ReqSrcReg[0], while DMAC_ReqSrcReg[2:1] remains unchanged. Writing hex 0x0yy leaves DMAC_ReqSrcReg[2:0] unchanged. This allows software to set a bit in the DMAC_ReqSrcReg
register without performing a read-modified write
• SRC_REQ[1:0]: Source request
• REQ_WE[9:8]: Request write enable
0 = Write disabled
1 = Write enabled
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24.4.17
Destination Software Transaction Request Register
Name: DMAC_ReqDstReg
Access: Read/write
Reset: 0x0
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
–
28
–
20
–
12
–
4
–
27
–
19
–
11
–
3
–
26
–
18
–
10
–
2
–
25
–
17
–
9
REQ_WE1
1
DST_REQ1
24
–
16
–
8
REQ_WE0
0
DST_REQ0
A bit is assigned for each channel in this register. DMAC_ReqDstReg[n] is ignored when software handshaking is not
enabled for the source of channel n.
A channel DST_REQ bit is written only if the corresponding channel write enable bit in the REQ_WE field is asserted on the
same AMBA write transfer.
• DST_REQ[1:0]: Destination request
• REQ_WE[9:8]: Request write enable
0 = Write disabled
1 = Write enabled
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24.4.18
Single Source Transaction Request Register
Name: DMAC_SglReqSrcReg
Access: Read/write
Reset: 0x0
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
–
28
–
20
–
12
–
4
–
27
–
19
–
11
–
3
–
26
–
18
–
10
–
2
–
25
–
17
–
9
REQ_WE1
1
S_SG_REQ1
24
–
16
–
8
REQ_WE0
0
S_SG_REQ0
A bit is assigned for each channel in this register. DMAC_SglReqSrcReg[n] is ignored when software handshaking is not
enabled for the source of channel n.
A channel S_SG_REQ bit is written only if the corresponding channel write enable bit in the REQ_WE field is asserted on
the same AMBA write transfer.
• S_SG_REQ[1:0]: Source single request
• REQ_WE[9:8]: Request write enable
0 = Write disabled
1 = Write enabled
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24.4.19
Single Destination Transaction Request Register
Name: DMAC_SglReqDstReg
Access: Read/write
Reset: 0x0
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
–
28
–
20
–
12
–
4
–
27
–
19
–
11
–
3
–
26
–
18
–
10
–
2
–
25
–
17
–
9
REQ_WE1
1
D_SG_REQ1
24
–
16
–
8
REQ_WE0
0
D_SG_REQ0
A bit is assigned for each channel in this register. DMAC_SglReqDstReg[n] is ignored when software handshaking is not
enabled for the source of channel n.
A channel D_SG_REQ bit is written only if the corresponding channel write enable bit in the REQ_WE field is asserted on
the same AMBA write transfer.
• D_SG_REQ[1:0]: Destination single request
• REQ_WE[9:8]: Request write enable
0 = Write disabled
1 = Write enabled
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24.4.20
Last Source Transaction Request Register
Name: DMAC_LstSrcReqReg
Access: Read/write
Reset: 0x0
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
–
28
–
20
–
12
–
4
–
27
–
19
–
11
–
3
–
26
–
18
–
10
–
2
–
25
–
17
–
9
LSTSR_WE1
1
LSTSRC1
24
–
16
–
8
LSTSR_WE0
0
LSTSRC0
A bit is assigned for each channel in this register. LstSrcReqReg[n] is ignored when software handshaking is not enabled
for the source of channel n.
A channel LSTSRC bit is written only if the corresponding channel write enable bit in the LSTSR_WE field is asserted on
the same AMBA write transfer.
• LSTSRC[1:0]: Source Last Transaction request
• LSTSR_WE[9:8]: Source Last Transaction request write enable
0 = Write disabled
1 = Write enabled
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24.4.21
Last Destination Transaction Request Register
Name: DMAC_LstDstReqReg
Access: Read/write
Reset: 0x0
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
–
28
–
20
–
12
–
4
–
27
–
19
–
11
–
3
–
26
–
18
–
10
–
2
–
25
–
17
–
9
LSTDS_WE1
1
LSTDST1
24
–
16
–
8
LSTDS_WE0
0
LSTDST0
A bit is assigned for each channel in this register. LstDstReqReg[n] is ignored when software handshaking is not enabled
for the source of channel n.
A channel LSTDST bit is written only if the corresponding channel write enable bit in the LSTDS_WE field is asserted on
the same AMBA write transfer.
• LSTDST[1:0]: Destination Last Transaction request
• LSTDS_WE[9:8]: Destination Last Transaction request write enable
0 = Write disabled
1 = Write enabled
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6249B–ATARM–14-Dec-06
24.4.22
DMAC Configuration Register
Name: DMAC_DmaCfgReg
Access: Read/Write
Reset: 0x0
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
–
28
–
20
–
12
–
4
–
27
–
19
–
11
–
3
–
26
–
18
–
10
–
2
–
25
–
17
–
9
–
1
–
24
–
16
–
8
–
0
DMA_EN
• DMA_EN: DMA Controller Enable
0 = DMAC Disabled
1 = DMAC Enabled.
This register is used to enable the DMAC, which must be done before any channel activity can begin.
If the global channel enable bit is cleared while any channel is still active, then DMAC_DmaCfgReg.DMA_EN still returns
‘1’ to indicate that there are channels still active until hardware has terminated all activity on all channels, at which point the
DMAC_DmaCfgReg.DMA_EN bit returns ‘0’.
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24.4.23
DMAC Channel Enable Register
Name: DMAC_ChEnReg
Access: Read/Write
Reset: 0x0
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
–
28
–
20
–
12
–
4
–
27
–
19
–
11
–
3
–
26
–
18
–
10
–
2
–
25
–
17
–
9
CH_EN_WE1
1
CH_EN1
24
–
16
–
8
CH_EN_WE0
0
CH_EN0
• CH_EN[1:0]
0 = Disable the Channel
1 = Enable the Channel
Enables/Disables the channel. Setting this bit enables a channel, clearing this bit disables the channel.
The DMAC_ChEnReg.CH_EN bit is automatically cleared by hardware to disable the channel after the last AMBA transfer
of the DMA transfer to the destination has completed.Software can therefore poll this bit to determine when a DMA transfer
has completed.
• CH_EN_WE[9:8]
The channel enable bit, CH_EN, is only written if the corresponding channel write enable bit, CH_EN_WE, is asserted on
the same AMBA write transfer.
For example, writing 0x101 writes a 1 into DMAC_ChEnReg[0], while DMAC_ChEnReg[7:1] remains unchanged.
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6249B–ATARM–14-Dec-06
24.4.24
DMAC ID Register
Name: DMAC_IdReg
Access: Read/Write
Reset: 0x0
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
ID
23
22
21
20
15
14
13
12
ID
ID
7
6
5
4
ID
• ID : 0x203a125a
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25. Peripheral DMA Controller (PDC)
25.1
Description
The Peripheral DMA Controller (PDC) transfers data between on-chip serial peripherals and
the on- and/or off-chip memories. The link between the PDC and a serial peripheral is operated by the AHB to ABP bridge.
The PDC contains twenty channels. The full-duplex peripherals feature eighteen mono-directional channels used in pairs (transmit only or receive only). The half-duplex peripherals
feature two bi-directional channels.
The user interface of each PDC channel is integrated into the user interface of the peripheral it
serves. The user interface of mono directional channels (receive only or transmit only), contains two 32-bit memory pointers and two 16-bit counters, one set (pointer, counter) for current
transfer and one set (pointer, counter) for next transfer. The bi-directional channel user interface contains four 32-bit memory pointers and four 16-bit counters. Each set (pointer, counter)
is used by current transmit, next transmit, current receive and next receive.
Using the PDC removes processor overhead by reducing its intervention during the transfer.
This significantly reduces the number of clock cycles required for a data transfer, which
improves microcontroller performance.
To launch a transfer, the peripheral triggers its associated PDC channels by using transmit
and receive signals. When the programmed data is transferred, an end of transfer interrupt is
generated by the peripheral itself.
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6249B–ATARM–14-Dec-06
25.2
Block Diagram
Figure 25-1. Block Diagram
FULL DUPLEX
PERIPHERAL
PDC
THR
PDC Channel A
RHR
PDC Channel B
Control
Status & Control
HALF DUPLEX
PERIPHERAL
Control
THR
PDC Channel C
RHR
Control
Status & Control
RECEIVE or TRANSMIT
PERIPHERAL
RHR or THR
Control
320
PDC Channel D
Status & Control
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25.3
25.3.1
Functional Description
Configuration
The PDC channel user interface enables the user to configure and control data transfers for
each channel. The user interface of each PDC channel is integrated into the associated
peripheral user interface.
The user interface of a serial peripheral, whether it is full or half duplex, contains four 32-bit
pointers (RPR, RNPR, TPR, TNPR) and four 16-bit counter registers (RCR, RNCR, TCR,
TNCR). However, the transmit and receive parts of each type are programmed differently: the
transmit and receive parts of a full duplex peripheral can be programmed at the same time,
whereas only one part (transmit or receive) of a half duplex peripheral can be programmed at
a time.
32-bit pointers define the access location in memory for current and next transfer, whether it is
for read (transmit) or write (receive). 16-bit counters define the size of current and next transfers. It is possible, at any moment, to read the number of transfers left for each channel.
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 associated peripheral status register. Transfers can be enabled and/or disabled by setting TXTEN/TXTDIS and RXTEN/RXTDIS
in the peripheral’s Transfer Control Register.
At the end of a transfer, the PDC channel sends status flags to its associated peripheral.
These flags are visible in the peripheral status register (ENDRX, ENDTX, RXBUFF, and
TXBUFE). Refer to Section 25.3.3 and to the associated peripheral user interface.
25.3.2
Memory Pointers
Each full duplex peripheral is connected to the PDC by a receive channel and a transmit channel. Both channels have 32-bit memory pointers that point respectively to a receive area and
to a transmit area in on- and/or off-chip memory.
Each half duplex peripheral is connected to the PDC by a bidirectional channel. This channel
has two 32-bit memory pointers, one for current transfer and the other for next transfer. These
pointers point to transmit or receive data depending on the operating mode of the peripheral.
Depending on the type of transfer (byte, half-word or word), the memory pointer is incremented respectively by 1, 2 or 4 bytes.
If a memory pointer address changes in the middle of a transfer, the PDC channel continues
operating using the new address.
25.3.3
Transfer Counters
Each channel has two 16-bit counters, one for current transfer and the other one for next
transfer. These counters define the size of data to be transferred by the channel. The current
transfer counter is decremented first as the data addressed by current memory pointer starts
to be transferred. When the current transfer counter reaches zero, the channel checks its next
transfer counter. If the value of next counter is zero, the channel stops transferring data and
sets the appropriate flag. But if the next counter value is greater then zero, the values of the
next pointer/next counter are copied into the current pointer/current counter and the channel
resumes the transfer whereas next pointer/next counter get zero/zero as values. At the end of
this transfer the PDC channel sets the appropriate flags in the Peripheral Status Register.
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The following list gives an overview of how status register flags behave depending on the
counters’ values:
• 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.
25.3.4
Data Transfers
The serial peripheral triggers its associated PDC channels’ transfers using transmit enable
(TXEN) and receive enable (RXEN) flags in the transfer control register integrated in the
peripheral’s user interface.
When the peripheral receives an external data, it sends a Receive Ready signal to its PDC
receive channel which then requests access to the Matrix. When access is granted, the PDC
receive channel starts reading the peripheral Receive Holding Register (RHR). The read data
are stored in an internal buffer and then written to memory.
When the peripheral is about to send data, it sends a Transmit Ready to its PDC transmit
channel which then requests access to the Matrix. When access is granted, the PDC transmit
channel reads data from memory and puts them to Transmit Holding Register (THR) of its
associated peripheral. The same peripheral sends data according to its mechanism.
25.3.5
PDC Flags and Peripheral Status Register
Each peripheral connected to the PDC sends out receive ready and transmit ready flags and
the PDC sends back flags to the peripheral. All these flags are only visible in the Peripheral
Status Register.
Depending on the type of peripheral, half or full duplex, the flags belong to either one single
channel or two different channels.
25.3.5.1
Receive Transfer End
This flag is set when PERIPH_RCR register reaches zero and the last data has been transferred to memory.
It is reset by writing a non zero value in PERIPH_RCR or PERIPH_RNCR.
25.3.5.2
Transmit Transfer End
This flag is set when PERIPH_TCR register reaches zero and the last data has been written
into peripheral THR.
It is reset by writing a non zero value in PERIPH_TCR or PERIPH_TNCR.
25.3.5.3
Receive Buffer Full
This flag is set when PERIPH_RCR register reaches zero with PERIPH_RNCR also set to
zero and the last data has been transferred to memory.
It is reset by writing a non zero value in PERIPH_TCR or PERIPH_TNCR.
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25.3.5.4
Transmit Buffer Empty
This flag is set when PERIPH_TCR register reaches zero with PERIPH_TNCR also set to zero
and the last data has been written into peripheral THR.
It is reset by writing a non zero value in PERIPH_TCR or PERIPH_TNCR.
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25.4
Peripheral DMA Controller (PDC) User Interface
Table 25-1.
Offset
Memory Map
Register
Name
(1)
Access
Reset State
0x100
Receive Pointer Register
PERIPH _RPR
Read/Write
0
0x104
Receive Counter Register
PERIPH_RCR
Read/Write
0
0x108
Transmit Pointer Register
PERIPH_TPR
Read/Write
0
0x10C
Transmit Counter Register
PERIPH_TCR
Read/Write
0
0x110
Receive Next Pointer Register
PERIPH_RNPR
Read/Write
0
0x114
Receive Next Counter Register
PERIPH_RNCR
Read/Write
0
0x118
Transmit Next Pointer Register
PERIPH_TNPR
Read/Write
0
0x11C
Transmit Next Counter Register
PERIPH_TNCR
Read/Write
0
0x120
Transfer Control Register
PERIPH_PTCR
Write
0
0x124
Transfer Status Register
PERIPH_PTSR
Read
0
Note:
324
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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25.4.1
Receive Pointer Register
Register Name:
PERIPH_RPR
Access Type:
Read/Write
31
30
29
28
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 Register
RXPTR must be set to receive buffer address.
When a half duplex peripheral is connected to the PDC, RXPTR = TXPTR.
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25.4.2
Receive Counter Register
Register Name:
PERIPH_RCR
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
RXCTR
7
6
5
4
RXCTR
• RXCTR: Receive Counter Register
RXCTR must be set to receive buffer size.
When a half duplex peripheral is connected to the PDC, RXCTR = TXCTR.
0 = Stops peripheral data transfer to the receiver
1 - 65535 = Starts peripheral data transfer if corresponding channel is active
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25.4.3
Transmit Pointer Register
Register Name:
PERIPH_TPR
Access Type:
Read/Write
31
30
29
28
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 Counter Register
TXPTR must be set to transmit buffer address.
When a half duplex peripheral is connected to the PDC, RXPTR = TXPTR.
25.4.4
Transmit Counter Register
Register Name:
PERIPH_TCR
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
TXCTR
7
6
5
4
TXCTR
• TXCTR: Transmit Counter Register
TXCTR must be set to transmit buffer size.
When a half duplex peripheral is connected to the PDC, RXCTR = TXCTR.
0 = Stops peripheral data transfer to the transmitter
1- 65535 = Starts peripheral data transfer if corresponding channel is active
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25.4.5
Receive Next Pointer Register
Register Name:
PERIPH_RNPR
Access Type:
Read/Write
31
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
RXNPTR contains next receive buffer address.
When a half duplex peripheral is connected to the PDC, RXNPTR = TXNPTR.
25.4.6
Receive Next Counter Register
Register Name:
PERIPH_RNCR
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
RXNCTR
7
6
5
4
RXNCTR
• RXNCTR: Receive Next Counter
RXNCTR contains next receive buffer size.
When a half duplex peripheral is connected to the PDC, RXNCTR = TXNCTR.
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25.4.7
Transmit Next Pointer Register
Register Name:
PERIPH_TNPR
Access Type:
Read/Write
31
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
TXNPTR contains next transmit buffer address.
When a half duplex peripheral is connected to the PDC, RXNPTR = TXNPTR.
25.4.8
Transmit Next Counter Register
Register Name:
PERIPH_TNCR
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
TXNCTR
7
6
5
4
TXNCTR
• TXNCTR: Transmit Counter Next
TXNCTR contains next transmit buffer size.
When a half duplex peripheral is connected to the PDC, RXNCTR = TXNCTR.
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25.4.9
Transfer Control Register
Register Name:
PERIPH_PTCR
Access Type:
Write
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
–
14
–
13
–
12
–
11
–
10
–
9
TXTDIS
8
TXTEN
7
–
6
–
5
–
4
–
3
–
2
–
1
RXTDIS
0
RXTEN
• RXTEN: Receiver Transfer Enable
0 = No effect.
1 = Enables PDC receiver channel requests if RXTDIS is not set.
When a half duplex peripheral is connected to the PDC, enabling the receiver channel requests automatically disables the
transmitter channel requests. It is forbidden to set both TXTEN and RXTEN for a half duplex peripheral.
• RXTDIS: Receiver Transfer Disable
0 = No effect.
1 = Disables the PDC receiver channel requests.
When a half duplex peripheral is connected to the PDC, disabling the receiver channel requests also disables the transmitter channel requests.
• TXTEN: Transmitter Transfer Enable
0 = No effect.
1 = Enables the PDC transmitter channel requests.
When a half duplex peripheral is connected to the PDC, it enables the transmitter channel requests only if RXTEN is not
set. It is forbidden to set both TXTEN and RXTEN for a half duplex peripheral.
• TXTDIS: Transmitter Transfer Disable
0 = No effect.
1 = Disables the PDC transmitter channel requests.
When a half duplex peripheral is connected to the PDC, disabling the transmitter channel requests disables the receiver
channel requests.
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25.4.10
Transfer Status Register
Register Name:
PERIPH_PTSR
Access Type:
Read
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
–
14
–
13
–
12
–
11
–
10
–
9
–
8
TXTEN
7
–
6
–
5
–
4
–
3
–
2
–
1
–
0
RXTEN
• RXTEN: Receiver Transfer Enable
0 = PDC Receiver channel requests are disabled.
1 = PDC Receiver channel requests are enabled.
• TXTEN: Transmitter Transfer Enable
0 = PDC Transmitter channel requests are disabled.
1 = PDC Transmitter channel requests are enabled.
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26. Clock Generator
26.1
Description
The Clock Generator is made up of 2 PLLs, a Main Oscillator, and a 32.768 kHz low-power
Oscillator.
It provides the following clocks:
• SLCK, the Slow Clock, which is the only permanent clock within the system
• MAINCK is the output of the Main Oscillator
The Clock Generator User Interface is embedded within the Power Management Controller
one and is described in Section 27.9. However, the Clock Generator registers are named
CKGR_.
• PLLACK is the output of the Divider and PLL A block
• PLLBCK is the output of the Divider and PLL B block
26.2
Slow Clock Crystal Oscillator
The Clock Generator integrates a 32.768 kHz low-power 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 26-1.
Figure 26-1. Typical Slow Clock Crystal Oscillator Connection
XIN32
XOUT32
GNDPLL
32,768 Hz
Crystal
CL1
26.3
CL2
Main Oscillator
Figure 26-2 shows the Main Oscillator block diagram.
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6249B–ATARM–14-Dec-06
Figure 26-2. Main Oscillator Block Diagram
MOSCEN
XIN
Main
Oscillator
XOUT
MAINCK
Main Clock
OSCOUNT
Main
Oscillator
Counter
SLCK
Slow Clock
Main Clock
Frequency
Counter
26.3.1
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 26-3. The 1 kΩ resistor is
only required for crystals with frequencies lower than 8 MHz. For further details on the electrical characteristics of the Main Oscillator, see the section “DC Characteristics” of the product
datasheet.
Figure 26-3. Typical Crystal Connection
XIN
XOUT
GND
1K
CL1
CL2
26.3.2
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.
26.3.3
Main Oscillator Control
To minimize the power required to start up the system, the main oscillator is disabled after
reset and slow clock is selected.
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.
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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 in PMC_SR (Status Register) is cleared and the counter starts
counting down on the slow clock divided by 8 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.
26.3.4
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 MAINRDY bit 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.
26.3.5
26.4
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 XIN pin. The input characteristics of the XIN pin
under these conditions are given in the product electrical characteristics section. The programmer has to be sure to set the OSCBYPASS bit to 1 and the MOSCEN bit to 0 in the Main OSC
register (CKGR_MOR) for the external clock to operate properly.
Divider and PLL Block
The PLL embeds an input divider to increase the accuracy of the resulting clock signals. However, the user must respect the PLL minimum input frequency when programming the divider.
Figure 26-4 shows the block diagram of the divider and PLL blocks.
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6249B–ATARM–14-Dec-06
Figure 26-4. Divider and PLL Blocks Block Diagram
DIVB
MULB
Divider B
MAINCK
OUTB
PLL B
PLLBCK
PLLRCB
DIVA
MULA
OUTA
PLL A
Divider A
PLLACK
PLLRCA
PLLBCOUNT
PLL B
Counter
LOCKB
PLLACOUNT
PLL A
Counter
SLCK
26.4.1
LOCKA
PLL Filter
The PLL requires connection to an external second-order filter through the pin, either PPLRCA
or PLLRCB. Figure 26-5 shows a schematic of these filters.
Figure 26-5. PLL Capacitors and Resistors
PLLRC
PLL
R
C2
C1
GND
Values of R, C1 and C2 to be connected to the PLLRC pin 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.
26.4.2
336
Divider and Phase Lock Loop Programming
The divider can be set between 1 and 255 in steps of 1. When a divider field (DIV) is set to 0,
the output of the corresponding divider and the PLL output is a continuous signal at level 0. On
reset, each DIV field is set to 0, thus the corresponding PLL input clock is set to 0.
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The PLL allows multiplication of the divider’s outputs. The PLL clock signal has a frequency
that depends on the respective source signal frequency and on the parameters DIV and MUL.
The factor applied to the source signal frequency is (MUL + 1)/DIV. When MUL is written to 0,
the corresponding PLL is disabled and its power consumption is saved. Re-enabling the PLL
can be performed by writing a value higher than 0 in the MUL field.
Whenever the PLL is re-enabled or one of its parameters is changed, the LOCK bit (LOCKA or
LOCKB) in PMC_SR is automatically cleared. The values written in the PLLCOUNT field
(PLLACOUNT or PLLBCOUNT) in CKGR_PLLR (CKGR_PLLAR or CKGR_PLLBR), are
loaded in the PLL counter. The PLL counter then decrements at the speed of the Slow Clock
until it reaches 0. At this time, the 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 PLLCOUNT field. The transient time depends on the PLL filter. The
initial state of the PLL and its target frequency can be calculated using a specific tool provided
by Atmel.
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27. Power Management Controller (PMC)
27.1
Description
The Power Management Controller (PMC) optimizes power consumption by controlling all
system and user peripheral clocks. The PMC enables/disables the clock inputs to many of the
peripherals and the ARM Processor.
The Power Management Controller provides the following clocks:
• MCK, the Master Clock, 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), switched off when entering processor in 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.
• UHP Clock (UHPCK), required by USB Host Port operations.
• Programmable Clock Outputs can be selected from the clocks provided by the clock
generator and driven on the PCKx pins.
27.2
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 provides a Slow Clock signal to the whole device. Selecting the Main Clock
saves power consumption of the PLLs.
The Master Clock Controller is made up of a clock selector and a prescaler. It also contains a
Master Clock divider which 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.
The Master Clock divider can be programmed 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 highspeed clock to a lower one to inform the software when the change is actually done.
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Figure 27-1. Master Clock Controller
PMC_MCKR
PMC_MCKR
CSS
PMC_MCKR
MDIV
PRES
SLCK
MAINCK
Master
Clock
Divider
Master Clock
Prescaler
PLLACK
MCK
PLLBCK
To the Processor
Clock Controller (PCK)
27.3
Processor Clock Controller
The PMC features a Processor Clock Controller (PCK) that implements the Processor 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).
The Processor Clock PCK is enabled after a reset and is automatically re-enabled by any
enabled interrupt. The Processor Idle Mode is achieved by disabling the Processor Clock,
which is automatically re-enabled 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.
27.4
USB Clock Controller
The USB Source Clock is always generated from the PLL B output. If using the USB, the user
must program the PLL to generate a 48 MHz, a 96 MHz or a 192 MHz signal with an accuracy
of ± 0.25% depending on the USBDIV bit in CKGR_PLLBR (see Figure 27-2).
When the PLL B output is stable, i.e., the LOCKB is set:
• The USB host clock can be enabled by setting the UHP bit in PMC_SCER. To save power
on this peripheral when it is not used, the user can set the UHP bit in PMC_SCDR. The
UHP bit in PMC_SCSR gives the activity of this clock. The USB host port require both the
12/48 MHz signal and the Master Clock. The Master Clock may be controlled via the
Peripheral Clock Controller.
Figure 27-2. USB Clock Controller
USBDIV
USB
Source
Clock
UDP Clock (UDPCK)
Divider
/1,/2,/4
UDP
UHP Clock (UHPCK)
UHP
27.5
Peripheral Clock Controller
The Power Management Controller controls the clocks of each embedded peripheral by the
way of the Peripheral Clock Controller. The user can individually enable and disable the Mas-
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6249B–ATARM–14-Dec-06
ter 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. 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.
27.6
Programmable Clock Output Controller
The PMC controls 4 signals to be output on external pins PCKx. Each signal can be independently programmed via the PMC_PCKx registers.
PCKx can be independently selected between the Slow clock, the PLL A output, the PLL B
output and the main clock by writing the CSS field in PMC_PCKx. Each output signal can also
be divided by a power of 2 between 1 and 64 by writing the PRES (Prescaler) field in
PMC_PCKx.
Each output signal can be enabled and disabled by writing 1 in the corresponding bit, PCKx of
PMC_SCER and PMC_SCDR, respectively. Status of the active programmable output clocks
are given in the PCKx bits of PMC_SCSR (System Clock Status Register).
Moreover, like the PCK, 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.
27.7
Programming Sequence
1. Enabling the Main Oscillator:
The main oscillator is enabled by setting the MOSCEN field in the CKGR_MOR register. In
some cases it may be advantageous to define a start-up time. This can be achieved by
writing a value in the OSCOUNT field in the CKGR_MOR register.
Once this register has been correctly configured, the user must wait for MOSCS field in the
PMC_SR register to be set. This can be done either by polling the status register or by
waiting the interrupt line to be raised if the associated interrupt to MOSCS has been
enabled in the PMC_IER register.
Code Example:
write_register(CKGR_MOR,0x00000701)
Start Up Time = 8 * OSCOUNT / SLCK = 56 Slow Clock Cycles.
Thus the main oscillator is enabled (MOSCS bit set) after 56 Slow Clock Cycles.
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2. Checking the Main Oscillator Frequency (Optional):
In some situations the user may need an accurate measure of the main oscillator frequency. This measure can be accomplished via the CKGR_MCFR register.
Once the MAINRDY field is set in CKGR_MCFR register, the user may read the MAINF
field in CKGR_MCFR register. This provides the number of main clock cycles within sixteen slow clock cycles.
3. Setting PLL A and divider A:
All parameters necessary to configure PLL A and divider A are located in the
CKGR_PLLAR register.
It is important to note that Bit 29 must always be set to 1 when programming the
CKGR_PLLAR register.
The DIVA field is used to control the divider A itself. The user can program a value between
0 and 255. Divider A output is divider A input divided by DIVA. By default, DIVA parameter
is set to 0 which means that divider A is turned off.
The OUTA field is used to select the PLL A output frequency range.
The MULA field is the PLL A multiplier factor. This parameter can be programmed between
0 and 2047. If MULA is set to 0, PLL A is turned off. Otherwise PLL A output frequency is
PLL A input frequency multiplied by (MULA + 1).
The PLLACOUNT field specifies the number of slow clock cycles before LOCKA bit is set
in the PMC_SR register after CKGR_PLLAR register has been written.
Once CKGR_PLLAR register has been written, the user is obliged to wait for the LOCKA
bit to be set in the PMC_SR register. This can be done either by polling the status register
or by waiting the interrupt line to be raised if the associated interrupt to LOCKA has been
enabled in the PMC_IER register.
All parameters in CKGR_PLLAR can be programmed in a single write operation. If at some
stage one of the following parameters, SRCA, MULA, DIVA is modified, LOCKA bit goes
low to indicate that PLL A is not ready yet. When PLL A is locked, LOCKA is set again.
User has to wait for LOCKA bit to be set before using the PLL A output clock.
Code Example:
write_register(CKGR_PLLAR,0x20030605)
PLL A and divider A are enabled. PLL A input clock is main clock divided by 5. PLL An output clock is PLL A input clock multiplied by 4. Once CKGR_PLLAR has been written,
LOCKA bit is set after six slow clock cycles.
4. Setting PLL B and divider B:
All parameters needed to configure PLL B and divider B are located in the CKGR_PLLBR
register.
The DIVB field is used to control divider B itself. A value between 0 and 255 can be programmed. Divider B output is divider B input divided by DIVB parameter. By default DIVB
parameter is set to 0 which means that divider B is turned off.
The OUTB field is used to select the PLL B output frequency range.
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The MULB field is the PLL B multiplier factor. This parameter can be programmed between
0 and 2047. If MULB is set to 0, PLL B is turned off, otherwise the PLL B output frequency
is PLL B input frequency multiplied by (MULB + 1).
The PLLBCOUNT field specifies the number of slow clock cycles before LOCKB bit is set
in the PMC_SR register after CKGR_PLLBR register has been written.
Once the PMC_PLLB register has been written, the user must wait for the LOCKB bit to be
set in the PMC_SR register. This can be done either by polling the status register or by
waiting the interrupt line to be raised if the associated interrupt to LOCKB has been
enabled in the PMC_IER register. All parameters in CKGR_PLLBR can be programmed in
a single write operation. If at some stage one of the following parameters, MULB, DIVB is
modified, LOCKB bit goes low to indicate that PLL B is not ready yet. When PLL B is
locked, LOCKB is set again. The user is constrained to wait for LOCKB bit to be set before
using the PLL A output clock.
The USBDIV field is used to control the additional divider by 1, 2 or 4, which generates the
USB clock(s).
Code Example:
write_register(CKGR_PLLBR,0x00040805)
If PLL B and divider B are enabled, the PLL B input clock is the main clock. PLL B output
clock is PLL B input clock multiplied by 5. Once CKGR_PLLBR has been written, LOCKB
bit is set after eight slow clock cycles.
5. Selection of Master Clock and Processor Clock
The Master Clock and the Processor Clock are configurable via the PMC_MCKR register.
The CSS field is used to select the Master Clock divider source. By default, the selected
clock source is slow clock.
The PRES field is used to control the Master Clock prescaler. The user can choose
between different values (1, 2, 4, 8, 16, 32, 64). Master Clock output is prescaler input
divided by PRES parameter. By default, PRES parameter is set to 1 which means that
master clock is equal to slow clock.
The MDIV field is used to control the Master Clock prescaler. It is possible to choose
between different values (0, 1, 2). The Master Clock output is Processor Clock divided by
1, 2 or 4, depending on the value programmed in MDIV. By default, MDIV is set to 0, which
indicates that the Processor Clock is equal to the Master Clock.
Once the PMC_MCKR register has been written, the user must wait for the MCKRDY bit to
be set in the PMC_SR register. This can be done either by polling the status register or by
waiting for the interrupt line to be raised if the associated interrupt to MCKRDY has been
enabled in the PMC_IER register.
The PMC_MCKR register must not be programmed in a single write operation. The preferred programming sequence for the PMC_MCKR register is as follows:
• If a new value for CSS field corresponds to PLL Clock,
– Program the PRES field in the PMC_MCKR register.
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– Wait for the MCKRDY bit to be set in the PMC_SR register.
– Program the CSS field in the PMC_MCKR register.
– Wait for the MCKRDY bit to be set in the PMC_SR register.
• If a new value for CSS field corresponds to Main Clock or Slow Clock,
– Program the CSS field in the PMC_MCKR register.
– Wait for the MCKRDY bit to be set in the PMC_SR register.
– Program the PRES field in the PMC_MCKR register.
– Wait for the MCKRDY bit to be set in the PMC_SR register.
If at some stage one of the following parameters, CSS or PRES, is modified, the MCKRDY
bit goes low to indicate that the Master Clock and the Processor Clock are not ready yet.
The user must wait for MCKRDY bit to be set again before using the Master and Processor
Clocks.
Note:
IF PLLx clock was selected as the Master Clock and the user decides to modify it by writing in
CKGR_PLLR (CKGR_PLLAR or CKGR_PLLBR), the MCKRDY flag goeso low while PLL is
unlocked. Once PLL is locked again, LOCK (LOCKA or LOCKB) goes high and MCKRDY is set.
While PLLA is unlocked, the Master Clock selection is automatically changed to Slow Clock..
While PLLB is unlocked, the Master Clock selection is automatically changed to Main Clock. For
further information, see Section 27.8.2. ”Clock Switching Waveforms” on page 346.
Code Example:
write_register(PMC_MCKR,0x00000001)
wait (MCKRDY=1)
write_register(PMC_MCKR,0x00000011)
wait (MCKRDY=1)
The Master Clock is main clock divided by 16.
The Processor Clock is the Master Clock.
6. Selection of Programmable clocks
Programmable clocks are controlled via registers; PMC_SCER, PMC_SCDR and
PMC_SCSR.
Programmable clocks can be enabled and/or disabled via the PMC_SCER and
PMC_SCDR registers. Depending on the system used, 4 Programmable clocks can be
enabled or disabled. The PMC_SCSR provides a clear indication as to which Programmable clock is enabled. By default all Programmable clocks are disabled.
PMC_PCKx registers are used to configure Programmable clocks.
The CSS field is used to select the Programmable clock divider source. Four clock options
are available: main clock, slow clock, PLLACK, PLLBCK. By default, the clock source
selected is slow clock.
The PRES field is used to control the Programmable clock prescaler. It is possible to
choose between different values (1, 2, 4, 8, 16, 32, 64). Programmable clock output is
prescaler input divided by PRES parameter. By default, the PRES parameter is set to 1
which means that master clock is equal to slow clock.
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Once the PMC_PCKx register has been programmed, The corresponding Programmable
clock must be enabled and the user is constrained to wait for the PCKRDYx bit to be set in
the PMC_SR register. This can be done either by polling the status register or by waiting
the interrupt line to be raised if the associated interrupt to PCKRDYx has been enabled in
the PMC_IER register. All parameters in PMC_PCKx can be programmed in a single write
operation.
If the CSS and PRES parameters are to be modified, the corresponding Programmable
clock must be disabled first. The parameters can then be modified. Once this has been
done, the user must re-enable the Programmable clock and wait for the PCKRDYx bit to be
set.
Code Example:
write_register(PMC_PCK0,0x00000015)
Programmable clock 0 is main clock divided by 32.
7. Enabling Peripheral Clocks
Once all of the previous steps have been completed, the peripheral clocks can be enabled
and/or disabled via registers PMC_PCER and PMC_PCDR.
Depending on the system used, 23 peripheral clocks can be enabled or disabled. The
PMC_PCSR provides a clear view as to which peripheral clock is enabled.
Note:
Each enabled peripheral clock corresponds to Master Clock.
Code Examples:
write_register(PMC_PCER,0x00000110)
Peripheral clocks 4 and 8 are enabled.
write_register(PMC_PCDR,0x00000010)
Peripheral clock 4 is disabled.
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27.8
27.8.1
Clock Switching Details
Master Clock Switching Timings
Table 27-1 and Table 27-2 give the worst case timings 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 27-1.
Clock Switching Timings (Worst Case)
From
Main Clock
SLCK
PLL Clock
–
4 x SLCK +
2.5 x Main Clock
3 x PLL Clock +
4 x SLCK +
1 x Main Clock
0.5 x Main Clock +
4.5 x SLCK
–
3 x PLL Clock +
5 x SLCK
0.5 x Main Clock +
4 x SLCK +
PLLCOUNT x SLCK +
2.5 x PLLx Clock
2.5 x PLL Clock +
5 x SLCK +
PLLCOUNT x SLCK
2.5 x PLL Clock +
4 x SLCK +
PLLCOUNT x SLCK
To
Main Clock
SLCK
PLL Clock
Notes:
1. PLL designates either the PLL A or the PLL B Clock.
2. PLLCOUNT designates either PLLACOUNT or PLLBCOUNT.
Table 27-2.
Clock Switching Timings Between Two PLLs (Worst Case)
From
PLLA Clock
PLLB Clock
PLLA Clock
2.5 x PLLA Clock +
4 x SLCK +
PLLACOUNT x SLCK
3 x PLLA Clock +
4 x SLCK +
1.5 x PLLA Clock
PLLB Clock
3 x PLLB Clock +
4 x SLCK +
1.5 x PLLB Clock
2.5 x PLLB Clock +
4 x SLCK +
PLLBCOUNT x SLCK
To
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27.8.2
Clock Switching Waveforms
Figure 27-3. Switch Master Clock from Slow Clock to PLL Clock
Slow Clock
PLL Clock
LOCK
MCKRDY
Master Clock
Write PMC_MCKR
Figure 27-4. Switch Master Clock from Main Clock to Slow Clock
Slow Clock
Main Clock
MCKRDY
Master Clock
Write PMC_MCKR
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Figure 27-5. Change PLLA Programming
Slow Clock
PLLA Clock
LOCK
MCKRDY
Master Clock
Slow Clock
Write CKGR_PLLAR
Figure 27-6. Change PLLB Programming
Main Clock
PLLB Clock
LOCK
MCKRDY
Master Clock
Main Clock
Write CKGR_PLLBR
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Figure 27-7. Programmable Clock Output Programming
PLL Clock
PCKRDY
PCKx Output
Write PMC_PCKx
PLL Clock is selected
Write PMC_SCER
Write PMC_SCDR
348
PCKx is enabled
PCKx is disabled
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27.9
Power Management Controller (PMC) User Interface
Table 27-3.
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
0x03
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
Read/Write
0x0
0x0024
Main Clock Frequency Register
CKGR_MCFR
Read-only
0x0
0x0028
PLL A Register
CKGR_PLLAR
ReadWrite
0x3F00
0x002C
PLL B Register
CKGR_PLLBR
ReadWrite
0x3F00
0x0030
Master Clock Register
PMC_MCKR
Read/Write
0x0
0x0038
Reserved
–
–
–
0x003C
Reserved
–
–
–
0x0040
Programmable Clock 0 Register
PMC_PCK0
Read/Write
0x0
0x0044
Programmable Clock 1 Register
PMC_PCK1
Read/Write
0x0
...
...
0x0060
Interrupt Enable Register
PMC_IER
Write-only
--
0x0064
Interrupt Disable Register
PMC_IDR
Write-only
--
0x0068
Status Register
PMC_SR
Read-only
0x08
0x006C
Interrupt Mask Register
PMC_IMR
Read-only
0x0
–
–
Write-only
–
–
–
...
0x0070 - 0x007C
0x0080
0x0084 - 0x00FC
Reserved
Charge Pump Current Register
Reserved
–
–
...
–
PMC_PLLICPR
–
...
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27.9.1
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
UDP
UHP
–
–
–
–
–
PCK
• PCK: Processor Clock Enable
0 = No effect.
1 = Enables the Processor clock.
• UHP: USB Host Port Clock Enable
0 = No effect.
1 = Enables the 12 and 48 MHz clock of the USB Host Port.
• UDP: USB Device Port Clock Enable
0 = No effect.
1 = Enables the 48 MHz clock of the USB Device Port.
• PCKx: Programmable Clock x Output Enable
0 = No effect.
1 = Enables the corresponding Programmable Clock output.
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27.9.2
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
UDP
UHP
–
–
–
–
–
PCK
• PCK: Processor Clock Disable
0 = No effect.
1 = Disables the Processor clock. This is used to enter the processor in Idle Mode.
• UHP: USB Host Port Clock Disable
0 = No effect.
1 = Disables the 12 and 48 MHz clock of the USB Host Port.
• UDP: USB Device Port Clock Disable
0 = No effect.
1 = Disables the 48 MHz clock of the USB Device Port.
• PCKx: Programmable Clock x Output Disable
0 = No effect.
1 = Disables the corresponding Programmable Clock output.
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27.9.3
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
UDP
UHP
–
–
–
–
–
PCK
• PCK: Processor Clock Status
0 = The Processor clock is disabled.
1 = The Processor clock is enabled.
• UHP: USB Host Port Clock Status
0 = The 12 and 48 MHz clock (UHPCK) of the USB Host Port is disabled.
1 = The 12 and 48 MHz clock (UHPCK) of the USB Host Port is enabled.
• UDP: USB Device Port Clock Status
0 = The 48 MHz clock (UDPCK) of the USB Device Port is disabled.
1 = The 48 MHz clock (UDPCK) of the USB Device Port is enabled.
• PCKx: Programmable Clock x Output Status
0 = The corresponding Programmable Clock output is disabled.
1 = The corresponding Programmable Clock output is enabled.
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27.9.4
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
-
-
• PIDx: Peripheral Clock x Enable
0 = No effect.
1 = Enables the corresponding peripheral clock.
Note:
PID2 to PID31 refer to identifiers as defined in the section “Peripheral Identifiers” in the product datasheet.
Note:
Programming the control bits of the Peripheral ID that are not implemented has no effect on the behavior of the PMC.
27.9.5
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
-
-
• PIDx: Peripheral Clock x Disable
0 = No effect.
1 = Disables the corresponding peripheral clock.
Note:
PID2 to PID31 refer to identifiers as defined in the section “Peripheral Identifiers” in the product datasheet.
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27.9.6
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
–
–
• PIDx: Peripheral Clock x Status
0 = The corresponding peripheral clock is disabled.
1 = The corresponding peripheral clock is enabled.
Note:
354
PID2 to PID31 refer to identifiers as defined in the section “Peripheral Identifiers” in the product datasheet.
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27.9.7
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.
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27.9.8
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.
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27.9.9
PMC Clock Generator PLL A Register
Register Name:
CKGR_PLLAR
Access Type:
Read/Write
31
–
30
–
29
1
28
–
23
22
21
20
27
–
26
25
MULA
24
19
18
17
16
10
9
8
2
1
0
MULA
15
14
13
12
11
OUTA
7
PLLACOUNT
6
5
4
3
DIVA
Possible limitations on PLL A input frequencies and multiplier factors should be checked before using the PMC.
Warning: Bit 29 must always be set to 1 when programming the CKGR_PLLAR register.
• 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
To optimize clock performance, this field must be programmed as specified in “PLL Characteristics” in the Electrical Characteristics section of the product datasheet.
• 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.
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27.9.10
PMC Clock Generator PLL B Register
Register Name:
CKGR_PLLBR
Access Type:
Read/Write
31
–
30
–
29
23
22
21
28
USBDIV
20
27
–
26
25
MULB
24
19
18
17
16
10
9
8
2
1
0
MULB
15
14
13
12
11
OUTB
7
PLLBCOUNT
6
5
4
3
DIVB
Possible limitations on PLL B input frequencies and multiplier factors should be checked before using the PMC.
• 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: PLLB Clock Frequency Range
To optimize clock performance, this field must be programmed as specified in “PLL Characteristics” in the Electrical Characteristics section of the product datasheet.
• MULB: PLL 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.
• USBDIV: Divider for USB Clock
USBDIV
358
Divider for USB Clock(s)
0
0
Divider output is PLL B clock output.
0
1
Divider output is PLL B clock output divided by 2.
1
0
Divider output is PLL B clock output divided by 4.
1
1
Reserved.
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27.9.11
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
–
–
–
–
–
–
4
3
2
7
6
5
–
–
–
8
MDIV
1
PRES
0
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: Processor Clock Prescaler
PRES
Processor 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
MDIV
Master Clock Division
0
0
Master Clock is Processor Clock.
0
1
Master Clock is Processor Clock divided by 2.
1
0
Master Clock is Processor Clock divided by 4.
1
1
Reserved.
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27.9.12
PMC Programmable Clock Register
Register Name:
PMC_PCKx
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
–
–
–
PRES
0
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
360
Programmable 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
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27.9.13
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
–
–
–
–
PCKRDY3
PCKRDY2
PCKRDY1
PCKRDY0
7
6
5
4
3
2
1
0
–
–
–
–
MCKRDY
LOCKB
LOCKA
MOSCS
• MOSCS: Main Oscillator Status Interrupt Enable
• LOCKA: PLL A Lock Interrupt Enable
• LOCKB: PLL B Lock Interrupt Enable
• MCKRDY: Master Clock Ready Interrupt Enable
• PCKRDYx: Programmable Clock Ready x Interrupt Enable
0 = No effect.
1 = Enables the corresponding interrupt.
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27.9.14
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
–
–
–
–
PCKRDY3
PCKRDY2
PCKRDY1
PCKRDY0
7
6
5
4
3
2
1
0
–
–
–
–
MCKRDY
LOCKB
LOCKA
MOSCS
• MOSCS: Main Oscillator Status Interrupt Disable
• LOCKA: PLL A Lock Interrupt Disable
• LOCKB: PLL B Lock Interrupt Disable
• MCKRDY: Master Clock Ready Interrupt Disable
• PCKRDYx: Programmable Clock Ready x Interrupt Disable
0 = No effect.
1 = Disables the corresponding interrupt.
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27.9.15
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
–
–
–
–
PCKRDY3
PCKRDY2
PCKRDY1
PCKRDY0
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: PLL A Lock Status
0 = PLL A is not locked
1 = PLL A is locked.
• LOCKB: PLL B Lock Status
0 = PLL B is not locked.
1 = PLL B is locked.
• MCKRDY: Master Clock Status
0 = Master Clock is not ready.
1 = Master Clock is ready.
• PCKRDYx: Programmable Clock Ready Status
0 = Programmable Clock x is not ready.
1 = Programmable Clock x is ready.
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27.9.16
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
–
–
–
–
PCKRDY3
PCKRDY2
PCKRDY1
PCKRDY0
7
6
5
4
3
2
1
0
–
–
–
–
MCKRDY
LOCKB
LOCKA
MOSCS
• MOSCS: Main Oscillator Status Interrupt Mask
• LOCKA: PLL A Lock Interrupt Mask
• LOCKB: PLL B Lock Interrupt Mask
• MCKRDY: Master Clock Ready Interrupt Mask
• PCKRDYx: Programmable Clock Ready x Interrupt Mask
0 = The corresponding interrupt is enabled.
1 = The corresponding interrupt is disabled.
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27.9.17
PLL Charge Pump Current Register
Register Name:
PMC_PLLICPR
Access Type:
Write-only
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
ICPPLLB
15
14
13
12
11
10
9
8
–
–
–
–
–
–
–
–
7
6
5
4
3
2
1
0
–
–
–
–
–
–
–
ICPPLLA
• ICPPLLA: Charge pump current
Must be set to 1.
• ICPPLLB: Charge pump current
Must be set to 1.
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28. Advanced Interrupt Controller (AIC)
28.1
Description
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.
The fast forcing feature redirects any internal or external interrupt source to provide a fast
interrupt rather than a normal interrupt.
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28.2
Block Diagram
Figure 28-1. Block Diagram
FIQ
AIC
ARM
Processor
IRQ0-IRQn
Up to
Thirty-two
Sources
Embedded
PeripheralEE
Embedded
nFIQ
nIRQ
Peripheral
Embedded
Peripheral
APB
28.3
Application Block Diagram
Figure 28-2. 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
28.4
AIC Detailed Block Diagram
Figure 28-3. AIC Detailed Block Diagram
Advanced Interrupt Controller
FIQ
PIO
Controller
Fast
Interrupt
Controller
External
Source
Input
Stage
ARM
Processor
nFIQ
nIRQ
IRQ0-IRQn
Embedded
Peripherals
Interrupt
Priority
Controller
Fast
Forcing
PIOIRQ
Internal
Source
Input
Stage
Processor
Clock
Power
Management
Controller
User Interface
Wake Up
APB
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28.5
I/O Line Description
Table 28-1.
I/O Line Description
Pin Name
Pin Description
Type
FIQ
Fast Interrupt
Input
IRQ0 - IRQn
Interrupt 0 - Interrupt n
Input
28.6
28.6.1
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.
28.6.2
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.
28.6.3
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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28.7
Functional Description
28.7.1
28.7.1.1
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 levelsensitive modes, or in positive edge-triggered or negative edge-triggered modes.
28.7.1.2
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.
28.7.1.3
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 “Priority Controller” on page 373.) The automatic
clear reduces the operations required by the interrupt service routine entry code to reading the
AIC_IVR. Note that the automatic interrupt clear is disabled if the interrupt source has the Fast
Forcing feature enabled as it is considered uniquely as a FIQ source. (For further details, See
“Fast Forcing” on page 377.)
The automatic clear of the interrupt source 0 is performed when AIC_FVR is read.
28.7.1.4
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 ”Priority Controller” on
page 373) 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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28.7.1.5
Figure 28-4.
Internal Interrupt Source Input Stage
Internal Interrupt Source Input Stage
AIC_SMRI
(SRCTYPE)
Level/
Edge
Source i
AIC_IPR
AIC_IMR
Fast Interrupt Controller
or
Priority Controller
Edge
AIC_IECR
Detector
Set Clear
FF
AIC_ISCR
AIC_ICCR
AIC_IDCR
28.7.1.6
External Interrupt Source Input Stage
Figure 28-5. External Interrupt Source Input Stage
High/Low
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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28.7.2
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.
28.7.2.1
External Interrupt Edge Triggered Source
Figure 28-6.
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
28.7.2.2
External Interrupt Level Sensitive Source
Figure 28-7.
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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28.7.2.3
Internal Interrupt Edge Triggered Source
Figure 28-8. Internal Interrupt Edge Triggered Source
MCK
nIRQ
Maximum IRQ Latency = 4.5 Cycles
Peripheral Interrupt
Becomes Active
28.7.2.4
Internal Interrupt Level Sensitive Source
Figure 28-9. Internal Interrupt Level Sensitive Source
MCK
nIRQ
Maximum IRQ Latency = 3.5 Cycles
Peripheral Interrupt
Becomes Active
28.7.3
28.7.3.1
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 (except for those programmed in Fast
Forcing).
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_SMR
(Source Mode 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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6249B–ATARM–14-Dec-06
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.
28.7.3.2
Interrupt Nesting
The priority controller utilizes interrupt nesting in order for the high 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.
28.7.3.3
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.
28.7.3.4
374
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:
– 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.
– 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.
– Automatically clears the interrupt, if it has been programmed to be edge-triggered.
– Pushes the current level and the current interrupt number on to the stack.
– 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 are
used and restoring them at the end. During this phase, an interrupt of higher priority
than the current level restarts 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 the effect of returning from the interrupt to whatever was
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6249B–ATARM–14-Dec-06
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.
Note:
28.7.4
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
28.7.4.1
Fast Interrupt Source
The interrupt source 0 is the only source which can raise a fast interrupt request to the processor except if fast forcing is used. The interrupt source 0 is generally connected to a FIQ pin of
the product, either directly or through a PIO Controller.
28.7.4.2
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.
28.7.4.3
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.
28.7.4.4
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:
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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 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.
28.7.4.5
Fast Forcing
The Fast Forcing feature of the advanced interrupt controller provides redirection of any normal Interrupt source on the fast interrupt controller.
Fast Forcing is enabled or disabled by writing to the Fast Forcing Enable Register
(AIC_FFER) and the Fast Forcing Disable Register (AIC_FFDR). Writing to these registers
results in an update of the Fast Forcing Status Register (AIC_FFSR) that controls the feature
for each internal or external interrupt source.
When Fast Forcing is disabled, the interrupt sources are handled as described in the previous
pages.
When Fast Forcing is enabled, the edge/level programming and, in certain cases, edge detection of the interrupt source is still active but the source cannot trigger a normal interrupt to the
processor and is not seen by the priority handler.
If the interrupt source is programmed in level-sensitive mode and an active level is sampled,
Fast Forcing results in the assertion of the nFIQ line to the core.
If the interrupt source is programmed in edge-triggered mode and an active edge is detected,
Fast Forcing results in the assertion of the nFIQ line to the core.
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The Fast Forcing feature does not affect the Source 0 pending bit in the Interrupt Pending
Register (AIC_IPR).
The FIQ Vector Register (AIC_FVR) reads the contents of the Source Vector Register 0
(AIC_SVR0), whatever the source of the fast interrupt may be. The read of the FVR does not
clear the Source 0 when the fast forcing feature is used and the interrupt source should be
cleared by writing to the Interrupt Clear Command Register (AIC_ICCR).
All enabled and pending interrupt sources that have the fast forcing feature enabled and that
are programmed in edge-triggered mode must be cleared by writing to the Interrupt Clear
Command Register. In doing so, they are cleared independently and thus lost interrupts are
prevented.
The read of AIC_IVR does not clear the source that has the fast forcing feature enabled.
The source 0, reserved to the fast interrupt, continues operating normally and becomes one of
the Fast Interrupt sources.
Figure 28-10. Fast Forcing
Source 0 _ FIQ
AIC_IPR
Input Stage
Automatic Clear
AIC_IMR
nFIQ
Read FVR if Fast Forcing is
disabled on Sources 1 to 31.
AIC_FFSR
Source n
AIC_IPR
Input Stage
Priority
Manager
Automatic Clear
AIC_IMR
nIRQ
Read IVR if Source n is the current interrupt
and if Fast Forcing is disabled on Source n.
28.7.5
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
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(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.
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. 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.
28.7.6
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.
28.7.7
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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28.8
Advanced Interrupt Controller (AIC) User Interface
28.8.1
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
support only a ± 4-Kbyte offset.
28.8.2
Register Mapping
Table 28-2.
Offset
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
FIQ Interrupt Vector Register
AIC_FVR
Read-only
0x0
0x108
Interrupt Status Register
AIC_ISR
Read-only
0x0
AIC_IPR
Read-only
0x0(1)
(2)
0x10C
Interrupt Pending Register
0x110
Interrupt Mask Register(2)
AIC_IMR
Read-only
0x0
0x114
Core Interrupt Status Register
AIC_CISR
Read-only
0x0
0x118
Reserved
---
---
---
0x11C
Reserved
---
---
---
AIC_IECR
Write-only
---
AIC_IDCR
Write-only
---
AIC_ICCR
Write-only
---
AIC_ISCR
Write-only
---
AIC_EOICR
Write-only
---
0x120
Interrupt Enable Command Register
(2)
0x124
Interrupt Disable Command Register
0x128
Interrupt Clear Command Register(2)
(2)
(2)
0x12C
Interrupt Set Command Register
0x130
End of Interrupt Command Register
0x134
Spurious Interrupt Vector Register
AIC_SPU
Read/Write
0x0
0x138
Debug Control Register
AIC_DCR
Read/Write
0x0
0x13C
Reserved
---
---
---
AIC_FFER
Write-only
---
0x140
(2)
Fast Forcing Enable Register
(2)
0x144
Fast Forcing Disable Register
AIC_FFDR
Write-only
---
0x148
Fast Forcing Status Register(2)
AIC_FFSR
Read-only
0x0
Notes:
380
Register Mapping
1. The reset value of this register depends on the level of the external interrupt source. All other sources are cleared at reset,
thus not pending.
2. PID2...PID31 bit fields refer to the identifiers as defined in the section “Peripheral Identifiers” of the product datasheet.
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28.8.3
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
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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28.8.4
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.
28.8.5
AIC Interrupt Vector Register
Register Name:
AIC_IVR
Access Type:
Read-only
Reset Value:
0x0
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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28.8.6
AIC FIQ Vector Register
Register Name:
AIC_FVR
Access Type:
Read-only
Reset Value:
0x0
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 FIQ Vector Register reads the value stored in AIC_SPU.
28.8.7
AIC Interrupt Status Register
Register Name:
AIC_ISR
Access Type:
Read-only
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
–
–
–
IRQID
• IRQID: Current Interrupt Identifier
The Interrupt Status Register returns the current interrupt source number.
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28.8.8
AIC Interrupt Pending Register
Register Name:
AIC_IPR
Access Type:
Read-only
Reset Value:
0x0
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 not pending.
1 = Corresponding interrupt is pending.
28.8.9
AIC Interrupt Mask Register
Register Name:
AIC_IMR
Access Type:
Read-only
Reset Value:
0x0
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.
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28.8.10
AIC Core Interrupt Status Register
Register Name:
AIC_CISR
Access Type:
Read-only
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
–
–
–
–
–
–
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.
28.8.11
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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28.8.12
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.
28.8.13
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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28.8.14
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.
28.8.15
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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28.8.16
AIC Spurious Interrupt Vector Register
Register Name:
AIC_SPU
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
SIQV
23
22
21
20
SIQV
15
14
13
12
SIQV
7
6
5
4
SIQV
• SIQV: Spurious Interrupt Vector Register
The user 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.
28.8.17
AIC Debug Control Register
Register Name:
AIC_DEBUG
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
–
–
–
–
–
–
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.
388
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AT91SAM9263 Preliminary
28.8.18
AIC Fast Forcing Enable Register
Register Name:
AIC_FFER
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
–
• SYS, PID2-PID31: Fast Forcing Enable
0 = No effect.
1 = Enables the fast forcing feature on the corresponding interrupt.
28.8.19
AIC Fast Forcing Disable Register
Register Name:
AIC_FFDR
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
–
• SYS, PID2-PID31: Fast Forcing Disable
0 = No effect.
1 = Disables the Fast Forcing feature on the corresponding interrupt.
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
28.8.20
AIC Fast Forcing Status Register
Register Name:
AIC_FFSR
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
SYS
–
• SYS, PID2-PID31: Fast Forcing Status
0 = The Fast Forcing feature is disabled on the corresponding interrupt.
1 = The Fast Forcing feature is enabled on the corresponding interrupt.
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
29. Debug Unit (DBGU)
29.1
Description
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 data 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.
391
6249B–ATARM–14-Dec-06
29.2
Block Diagram
Figure 29-1. Debug Unit Functional Block Diagram
Peripheral
Bridge
Peripheral DMA Controller
APB
Debug Unit
DTXD
Transmit
Power
Management
Controller
MCK
Parallel
Input/
Output
Baud Rate
Generator
Receive
DRXD
COMMRX
R
ARM
Processor
COMMTX
DCC
Handler
Chip ID
nTRST
ICE
Access
Handler
Interrupt
Control
dbgu_irq
Power-on
Reset
force_ntrst
Table 29-1.
Debug Unit Pin Description
Pin Name
Description
Type
DRXD
Debug Receive Data
Input
DTXD
Debug Transmit Data
Output
Figure 29-2. Debug Unit Application Example
Boot Program
Debug Monitor
Trace Manager
Debug Unit
RS232 Drivers
Programming Tool
392
Debug Console
Trace Console
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
29.3
29.3.1
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.
29.3.2
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.
29.3.3
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 291. This sharing requires the programmer to determine the source of the interrupt when the
source 1 is triggered.
29.4
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.
29.4.1
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
393
6249B–ATARM–14-Dec-06
Figure 29-3. Baud Rate Generator
CD
CD
MCK
16-bit Counter
OUT
>1
1
0
Divide
by 16
Baud Rate
Clock
0
Receiver
Sampling Clock
29.4.2
29.4.2.1
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.
29.4.2.2
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.
394
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AT91SAM9263 Preliminary
Figure 29-4. Start Bit Detection
Sampling Clock
DRXD
True Start
Detection
D0
Baud Rate
Clock
Figure 29-5. Character Reception
Example: 8-bit, parity enabled 1 stop
0.5 bit
period
1 bit
period
DRXD
D0
D1
True Start Detection
Sampling
29.4.2.3
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 29-6. 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
29.4.2.4
Receiver Overrun
If DBGU_RHR has not been read by the software (or the Peripheral Data 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 29-7. 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
29.4.2.5
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
395
6249B–ATARM–14-Dec-06
parity 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 29-8. Parity Error
DRXD
S
D0
D1
D2
D3
D4
D5
D6
D7
P
stop
RXRDY
PARE
Wrong Parity Bit
29.4.2.6
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 29-9. Receiver Framing Error
DRXD
S
D0
D1
D2
D3
D4
D5
D6
D7
P
stop
RXRDY
FRAME
Stop Bit
Detected at 0
29.4.3
29.4.3.1
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.
29.4.3.2
396
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
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
figure. The field 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 29-10. Character Transmission
Example: Parity enabled
Baud Rate
Clock
DTXD
Start
Bit
29.4.3.3
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 29-11. 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
29.4.4
Write Data 1
in DBGU_THR
Peripheral Data Controller
Both the receiver and the transmitter of the Debug Unit's UART are generally connected to a
Peripheral Data Controller (PDC) channel.
The peripheral data 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.
397
6249B–ATARM–14-Dec-06
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.
29.4.5
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 29-12. Test Modes
Automatic Echo
RXD
Receiver
Disabled
Transmitter
TXD
Local Loopback
Disabled
Receiver
RXD
VDD
Disabled
Transmitter
Remote Loopback
VDD
Receiver
Transmitter
29.4.6
398
TXD
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.
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
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.
29.4.7
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.
29.4.8
ICE Access Prevention
The Debug Unit allows blockage of access to the system through the ARM processor's ICE
interface. This feature is implemented via the register Force NTRST (DBGU_FNR), that allows
assertion of the NTRST signal of the ICE Interface. Writing the bit FNTRST (Force NTRST) to
1 in this register prevents any activity on the TAP controller.
On standard devices, the bit FNTRST resets to 0 and thus does not prevent ICE access.
This feature is especially useful on custom ROM devices for customers who do not want their
on-chip code to be visible.
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6249B–ATARM–14-Dec-06
29.5
Debug Unit (DBGU) User Interface
Table 29-2.
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
–
0x0048
Force NTRST Register
DBGU_FNR
Read/Write
0x0
0x004C - 0x00FC
Reserved
–
–
–
0x0100 - 0x0124
PDC Area
–
–
–
400
AT91SAM9263 Preliminary
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29.5.1
Debug Unit Control Register
Name:
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.
401
6249B–ATARM–14-Dec-06
29.5.2
Debug Unit Mode Register
Name:
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
402
Mode Description
0
0
Normal Mode
0
1
Automatic Echo
1
0
Local Loopback
1
1
Remote Loopback
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
29.5.3
Debug Unit Interrupt Enable Register
Name:
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.
403
6249B–ATARM–14-Dec-06
29.5.4
Debug Unit Interrupt Disable Register
Name:
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.
404
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
29.5.5
Debug Unit Interrupt Mask Register
Name:
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.
405
6249B–ATARM–14-Dec-06
29.5.6
Debug Unit Status Register
Name:
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 Data Controller channel is inactive.
1 = The End of Transfer signal from the receiver Peripheral Data Controller channel is active.
• ENDTX: End of Transmitter Transfer
0 = The End of Transfer signal from the transmitter Peripheral Data Controller channel is inactive.
1 = The End of Transfer signal from the transmitter Peripheral Data 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.
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.
406
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AT91SAM9263 Preliminary
• 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.
407
6249B–ATARM–14-Dec-06
29.5.7
Debug Unit Receiver Holding Register
Name:
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.
29.5.8
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.
408
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
29.5.9
Debug Unit Baud Rate Generator Register
Name:
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
Baud Rate Clock
0
Disabled
1
MCK
2 to 65535
MCK / (CD x 16)
409
6249B–ATARM–14-Dec-06
29.5.10
Debug Unit Chip ID Register
Name:
DBGU_CIDR
Access Type:
Read-only
31
30
29
EXT
23
28
27
26
NVPTYP
22
21
20
19
18
ARCH
15
14
13
6
24
17
16
9
8
1
0
SRAMSIZ
12
11
10
NVPSIZ2
7
25
ARCH
NVPSIZ
5
4
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™
1
0
1
ARM926EJ-S™
• NVPSIZ: Nonvolatile Program Memory Size
NVPSIZ
410
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
512K bytes
1
0
1
1
Reserved
1
1
0
0
1024K bytes
1
1
0
1
Reserved
1
1
1
0
2048K bytes
1
1
1
1
Reserved
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
• NVPSIZ2 Second Nonvolatile Program Memory Size
NVPSIZ2
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
512K bytes
1
0
1
1
Reserved
1
1
0
0
1024K bytes
1
1
0
1
Reserved
1
1
1
0
2048K bytes
1
1
1
1
Reserved
• 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
411
6249B–ATARM–14-Dec-06
• ARCH: Architecture Identifier
ARCH
Hex
Bin
Architecture
0x19
0001 1001
AT91SAM9xx Series
0x29
0010 1001
AT91SAM9XExx Series
0x34
0011 0100
AT91x34 Series
0x39
0011 1001
CAP9 Series
0x40
0100 0000
AT91x40 Series
0x42
0100 0010
AT91x42 Series
0x55
0101 0101
AT91x55 Series
0x60
0101 0000
AT91SAM7Axx Series
0x63
0110 0011
AT91x63 Series
0x70
0111 0000
AT91SAM7Sxx Series
0x71
0111 0001
AT91SAM7XCxx Series
0x72
0111 0010
AT91SAM7SExx Series
0x73
0111 0011
AT91SAM7Lxx Series
0x75
0111 0101
AT91SAM7Xxx Series
0x92
1001 0010
AT91x92 Series
0xF0
1111 0001
AT75Cxx 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
0
1
0
Embedded Flash Memory
0
1
1
ROM and Embedded Flash Memory
NVPSIZ is ROM size
NVPSIZ2 is Flash size
• EXT: Extension Flag
0 = Chip ID has a single register definition without extension
1 = An extended Chip ID exists.
412
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29.5.11
Debug Unit Chip ID Extension Register
Name:
DBGU_EXID
Access Type:
Read-only
31
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.
29.5.12
Debug Unit Force NTRST Register
Name:
DBGU_FNR
Access T ype:
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
–
–
–
–
–
–
–
FNTRST
• FNTRST: Force NTRST
0 = NTRST of the ARM processor’s TAP controller is driven by power-on reset.
1 = NTRST of the ARM processor’s TAP controller is held low.
413
6249B–ATARM–14-Dec-06
414
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AT91SAM9263 Preliminary
30. Parallel Input/Output (PIO) Controller
30.1
Description
The Parallel Input/Output (PIO) Controller 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 detection 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 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.
415
6249B–ATARM–14-Dec-06
30.2
Block Diagram
Figure 30-1. Block Diagram
PIO Controller
AIC
PMC
PIO Interrupt
PIO Clock
Data, Enable
Up to 32
peripheral IOs
Embedded
Peripheral
PIN 0
Data, Enable
PIN 1
Up to 32 pins
Embedded
Peripheral
Up to 32
peripheral IOs
PIN 31
APB
Figure 30-2. Application Block Diagram
On-Chip Peripheral Drivers
Keyboard Driver
Control & Command
Driver
On-Chip Peripherals
PIO Controller
Keyboard Driver
416
General Purpose I/Os
External Devices
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
30.3
30.3.1
Product Dependencies
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.
30.3.2
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.
30.3.3
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.
The user must configure the Power Management Controller before any access to the input line
information.
30.3.4
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.
417
6249B–ATARM–14-Dec-06
30.4
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 30-3. In this description each signal shown
represents but one of up to 32 possible indexes.
Figure 30-3. I/O Line Control Logic
PIO_OER[0]
PIO_OSR[0]
PIO_PUER[0]
PIO_ODR[0]
PIO_PUSR[0]
PIO_PUDR[0]
1
Peripheral A
Output Enable
0
0
Peripheral B
Output Enable
0
1
PIO_ASR[0]
PIO_PER[0]
PIO_ABSR[0]
1
PIO_PSR[0]
PIO_BSR[0]
PIO_PDR[0]
Peripheral A
Output
0
Peripheral B
Output
1
PIO_MDER[0]
PIO_MDSR[0]
PIO_MDDR[0]
0
0
PIO_SODR[0]
PIO_ODSR[0]
1
Pad
PIO_CODR[0]
1
Peripheral A
Input
PIO_PDSR[0]
PIO_ISR[0]
0
Edge
Detector
Glitch
Filter
Peripheral B
Input
(Up to 32 possible inputs)
PIO Interrupt
1
PIO_IFER[0]
PIO_IFSR[0]
PIO_IFDR[0]
PIO_IER[0]
PIO_IMR[0]
PIO_IDR[0]
PIO_ISR[31]
PIO_IER[31]
PIO_IMR[31]
PIO_IDR[31]
418
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
30.4.1
Pull-up Resistor Control
Each I/O line is designed with an embedded pull-up resistor. The pull-up resistor can be
enabled or disabled by writing 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.
After reset, all of the pull-ups are enabled, i.e., PIO_PUSR resets at the value 0x0.
30.4.2
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.
30.4.3
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.
30.4.4
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.
419
6249B–ATARM–14-Dec-06
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_ODR (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 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.
30.4.5
Synchronous Data Output
Controlling all parallel busses using several PIOs requires two successive write operations in
the PIO_SODR and PIO_CODR registers. This may lead to unexpected transient values. The
PIO controller offers a direct control of PIO outputs by single write access to PIO_ODSR (Output Data Status Register). Only bits unmasked by PIO_OSWSR (Output Write Status
Register) are written. The mask bits in the PIO_OWSR are set by writing to PIO_OWER (Output Write Enable Register) and cleared by writing to PIO_OWDR (Output Write Disable
Register).
After reset, the synchronous data output is disabled on all the I/O lines as PIO_OWSR resets
at 0x0.
30.4.6
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 (Multidriver 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.
30.4.7
420
Output Line Timings
Figure 30-4 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 30-4 also shows when the feedback in PIO_PDSR is available.
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Figure 30-4. 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
30.4.8
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.
30.4.9
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 30-5.
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.
421
6249B–ATARM–14-Dec-06
Figure 30-5. Input Glitch Filter Timing
MCK
up to 1.5 cycles
Pin Level
1 cycle
1 cycle
1 cycle
1 cycle
PIO_PDSR
if PIO_IFSR = 0
2 cycles
PIO_PDSR
if PIO_IFSR = 1
30.4.10
up to 2.5 cycles
1 cycle
up to 2 cycles
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 30-6. Input Change Interrupt Timings
MCK
Pin Level
PIO_ISR
Read PIO_ISR
422
APB Access
APB Access
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
30.5
I/O Lines Programming Example
The programing example as shown in Table 30-1 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), opendrain, 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 line 24 to 27 assigned to peripheral A with Input Change Interrupt and pull-up resistor
Table 30-1.
Programming Example
Register
Value to be Written
PIO_PER
0x0000 FFFF
PIO_PDR
0x0FFF 0000
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
423
6249B–ATARM–14-Dec-06
30.6
Parallel Input/Ouput (PIO) Controller 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 30-2.
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
Output Enable Register
PIO_OER
Write-only
–
0x0014
Output Disable Register
PIO_ODR
Write-only
–
0x0018
Output Status Register
PIO_OSR
Read-only
0x0000 0000
0x001C
Reserved
0x0020
Glitch Input Filter Enable Register
PIO_IFER
Write-only
–
0x0024
Glitch Input Filter Disable Register
PIO_IFDR
Write-only
–
0x0028
Glitch Input Filter Status Register
PIO_IFSR
Read-only
0x0000 0000
0x002C
Reserved
0x0030
Set Output Data Register
PIO_SODR
Write-only
–
0x0034
Clear Output Data Register
PIO_CODR
Write-only
–
0x0038
Output Data Status Register(2)
PIO_ODSR
Read-only
0x0000 0000
PIO_PDSR
Read-only
(3)
0x003C
Pin Data Status Register
0x0040
Interrupt Enable Register
PIO_IER
Write-only
–
0x0044
Interrupt Disable Register
PIO_IDR
Write-only
–
0x0048
Interrupt Mask Register
PIO_IMR
Read-only
0x00000000
PIO_ISR
Read-only
0x00000000
(4)
0x004C
Interrupt Status Register
0x0050
Multi-driver Enable Register
PIO_MDER
Write-only
–
0x0054
Multi-driver Disable Register
PIO_MDDR
Write-only
–
0x0058
Multi-driver Status Register
PIO_MDSR
Read-only
0x00000000
0x005C
Reserved
0x0060
Pull-up Disable Register
PIO_PUDR
Write-only
–
0x0064
Pull-up Enable Register
PIO_PUER
Write-only
–
0x0068
Pad Pull-up Status Register
PIO_PUSR
Read-only
0x00000000
0x006C
Reserved
424
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Table 30-2.
Register Mapping (Continued)
Offset
Register
0x0070
0x0074
Name
Peripheral A Select Register
(5)
Peripheral B Select Register
(5)
(5)
Access
Reset Value
PIO_ASR
Write-only
–
PIO_BSR
Write-only
–
PIO_ABSR
Read-only
0x00000000
0x0078
AB Status Register
0x007C
to
0x009C
Reserved
0x00A0
Output Write Enable
PIO_OWER
Write-only
–
0x00A4
Output Write Disable
PIO_OWDR
Write-only
–
0x00A8
Output Write Status Register
PIO_OWSR
Read-only
0x00000000
0x00AC
Reserved
Notes:
1.
2.
3.
4.
Reset value of PIO_PSR depends on the product implementation.
PIO_ODSR is Read-only or Read/Write depending on PIO_OWSR I/O lines.
Reset value of PIO_PDSR depends on the level of the I/O lines.
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.
425
6249B–ATARM–14-Dec-06
30.6.1
PIO Controller PIO Enable Register
Name:
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).
30.6.2
PIO Controller PIO Disable Register
Name:
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).
426
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
30.6.3
PIO Controller PIO Status Register
Name:
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).
427
6249B–ATARM–14-Dec-06
30.6.4
PIO Controller Output Enable Register
Name:
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.
30.6.5
PIO Controller Output Disable Register
Name:
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.
428
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
30.6.6
PIO Controller Output Status Register
Name:
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.
429
6249B–ATARM–14-Dec-06
30.6.7
PIO Controller Input Filter Enable Register
Name:
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.
30.6.8
PIO Controller Input Filter Disable Register
Name:
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.
430
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
30.6.9
PIO Controller Input Filter Status Register
Name:
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.
431
6249B–ATARM–14-Dec-06
30.6.10
PIO Controller Set Output Data Register
Name:
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.
30.6.11
PIO Controller Clear Output Data Register
Name:
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.
432
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
30.6.12
PIO Controller Output Data Status Register
Name:
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.
433
6249B–ATARM–14-Dec-06
30.6.13
PIO Controller Pin Data Status Register
Name:
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.
434
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
30.6.14
PIO Controller Interrupt Enable Register
Name:
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.
30.6.15
PIO Controller Interrupt Disable Register
Name:
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.
435
6249B–ATARM–14-Dec-06
30.6.16
PIO Controller Interrupt Mask Register
Name:
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.
30.6.17
PIO Controller Interrupt Status Register
Name:
PIO_ISR
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 Status
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.
436
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
30.6.18
PIO Multi-driver Enable Register
Name:
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.
30.6.19
PIO Multi-driver Disable Register
Name:
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.
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30.6.20
PIO Multi-driver Status Register
Name:
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.
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30.6.21
PIO Pull Up Disable Register
Name:
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.
30.6.22
PIO Pull Up Enable Register
Name:
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.
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30.6.23
PIO Pull Up Status Register
Name:
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.
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30.6.24
PIO Peripheral A Select Register
Name:
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.
30.6.25
PIO Peripheral B Select Register
Name:
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.
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30.6.26
PIO Peripheral A B Status Register
Name:
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.
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30.6.27
PIO Output Write Enable Register
Name:
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.
30.6.28
PIO Output Write Disable Register
Name:
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.
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30.6.29
PIO Output Write Status Register
Name:
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.
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31. Serial Peripheral Interface (SPI)
31.1
Description
The Serial Peripheral Interface (SPI) circuit is a synchronous serial data link that provides
communication with external devices in Master or Slave Mode. It also enables communication
between processors if an external processor is connected to the system.
The Serial Peripheral Interface is essentially a shift register that serially transmits data bits to
other SPIs. During a data transfer, one SPI system acts as the “master”' which controls the
data flow, while the other devices act as “slaves'' which have data shifted into and out by the
master. Different CPUs can take turn being masters (Multiple Master Protocol opposite to Single Master Protocol where one CPU is always the master while all of the others are always
slaves) and one master may simultaneously shift data into multiple slaves. However, only one
slave may drive its output to write data back to the master at any given time.
A slave device is selected when the master asserts its NSS signal. If multiple slave devices
exist, the master generates a separate slave select signal for each slave (NPCS).
The SPI system consists of two data lines and two control lines:
• Master Out Slave In (MOSI): This data line supplies the output data from the master shifted
into the input(s) of the slave(s).
• Master In Slave Out (MISO): This data line supplies the output data from a slave to the
input of the master. There may be no more than one slave transmitting data during any
particular transfer.
• Serial Clock (SPCK): This control line is driven by the master and regulates the flow of the
data bits. The master may transmit data at a variety of baud rates; the SPCK line cycles
once for each bit that is transmitted.
• Slave Select (NSS): This control line allows slaves to be turned on and off by hardware.
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31.2
Block Diagram
Figure 31-1. Block Diagram
PDC
APB
SPCK
MISO
PMC
MOSI
MCK
SPI Interface
PIO
NPCS0/NSS
NPCS1
NPCS2
Interrupt Control
NPCS3
SPI Interrupt
31.3
Application Block Diagram
Figure 31-2. 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
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31.4
Signal Description
Table 31-1.
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
31.5
31.5.1
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 SPI pins to their
peripheral functions.
31.5.2
Power Management
The SPI may be clocked through the Power Management Controller (PMC), thus the programmer must first configure the PMC to enable the SPI clock.
31.5.3
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.
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31.6
31.6.1
Functional Description
Modes of Operation
The SPI operates in Master Mode or in Slave Mode.
Operation in Master Mode is programmed by writing at 1 the MSTR bit in the Mode Register.
The pins NPCS0 to NPCS3 are all configured as outputs, the SPCK pin is driven, the MISO
line is wired on the receiver input and the MOSI line driven as an output by the transmitter.
If the MSTR bit is written at 0, the SPI operates in Slave Mode. The MISO line is driven by the
transmitter output, the MOSI line is wired on the receiver input, the SPCK pin is driven by the
transmitter to synchronize the receiver. The NPCS0 pin becomes an input, and is used as a
Slave Select signal (NSS). The pins NPCS1 to NPCS3 are not driven and can be used for
other purposes.
The data transfers are identically programmable for both modes of operations. The baud rate
generator is activated only in Master Mode.
31.6.2
Data Transfer
Four combinations of polarity and phase are available for data transfers. The clock polarity is
programmed with the CPOL bit in the Chip Select Register. The clock phase is programmed
with the NCPHA bit. These two parameters determine the edges of the clock signal on which
data is driven and sampled. Each of the two parameters has two possible states, resulting in
four possible combinations that are incompatible with one another. Thus, a master/slave pair
must use the same parameter pair values to communicate. If multiple slaves are used and
fixed in different configurations, the master must reconfigure itself each time it needs to communicate with a different slave.
Table 31-2 shows the four modes and corresponding parameter settings.
Table 31-2.
SPI Bus Protocol Mode
SPI Mode
CPOL
NCPHA
0
0
1
1
0
0
2
1
1
3
1
0
Figure 31-3 and Figure 31-4 show examples of data transfers.
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Figure 31-3. SPI Transfer Format (NCPHA = 1, 8 bits per transfer)
1
SPCK cycle (for reference)
2
3
4
6
5
7
8
SPCK
(CPOL = 0)
SPCK
(CPOL = 1)
MOSI
(from master)
MSB
MISO
(from slave)
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.
Figure 31-4. SPI Transfer Format (NCPHA = 0, 8 bits per transfer)
1
SPCK cycle (for reference)
2
3
4
5
7
6
8
SPCK
(CPOL = 0)
SPCK
(CPOL = 1)
MOSI
(from master)
MISO
(from slave)
*
MSB
6
5
4
3
2
1
MSB
6
5
4
3
2
1
LSB
LSB
NSS
(to slave)
* Not defined but normally LSB of previous character transmitted.
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31.6.3
Master Mode Operations
When configured in Master Mode, the SPI operates on the clock generated by the internal programmable baud rate generator. It fully controls the data transfers to and from the slave(s)
connected to the SPI bus. The SPI drives the chip select line to the slave and the serial clock
signal (SPCK).
The SPI features two holding registers, the Transmit Data Register and the Receive Data Register, and a single Shift Register. The holding registers maintain the data flow at a constant
rate.
After enabling the SPI, a data transfer begins when the processor writes to the SPI_TDR
(Transmit Data Register). The written data is immediately transferred in the Shift Register and
transfer on the SPI bus starts. While the data in the Shift Register is shifted on the MOSI line,
the MISO line is sampled and shifted in the Shift Register. Transmission cannot occur without
reception.
Before writting the TDR, the PCS field must be set in order to select a slave.
If new data is written in SPI_TDR during the transfer, it stays in it until the current transfer is
completed. Then, the received data is transferred from the Shift Register to SPI_RDR, the
data in SPI_TDR is loaded in the Shift Register and a new transfer starts.
The transfer of a data written in SPI_TDR in the Shift Register is indicated by the TDRE bit
(Transmit Data Register Empty) in the Status Register (SPI_SR). When new data is written in
SPI_TDR, this bit is cleared. The TDRE bit is used to trigger the Transmit PDC channel.
The end of transfer is indicated by the TXEMPTY flag in the SPI_SR register. If a transfer
delay (DLYBCT) is greater than 0 for the last transfer, TXEMPTY is set after the completion of
said delay. The master clock (MCK) can be switched off at this time.
The transfer of received data from the Shift Register in SPI_RDR is indicated by the RDRF bit
(Receive Data Register Full) in the Status Register (SPI_SR). When the received data is read,
the RDRF bit is cleared.
If the SPI_RDR (Receive Data Register) has not been read before new data is received, the
Overrun Error bit (OVRES) in SPI_SR is set. As long as this flag is set, data is loaded in
SPI_RDR. The user has to read the status register to clear the OVRES bit.
Figure 31-6 on page 452 shows a block diagram of the SPI when operating in Master Mode.
Figure 31-6 on page 452 shows a flow chart describing how transfers are handled.
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31.6.3.1
Master Mode Block Diagram
Figure 31-5. Master Mode Block Diagram
SPI_CSR0..3
SCBR
Baud Rate Generator
MCK
SPCK
SPI
Clock
SPI_CSR0..3
BITS
NCPHA
CPOL
LSB
MISO
SPI_RDR
RDRF
OVRES
RD
MSB
Shift Register
MOSI
SPI_TDR
TD
SPI_CSR0..3
CSAAT
TDRE
SPI_RDR
PCS
PS
NPCS3
PCSDEC
SPI_MR
PCS
0
NPCS2
Current
Peripheral
NPCS1
SPI_TDR
NPCS0
PCS
1
MSTR
MODF
NPCS0
MODFDIS
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31.6.3.2
Master Mode Flow Diagram
Figure 31-6. Master Mode Flow Diagram S
SPI Enable
- NPCS defines the current Chip Select
- CSAAT, DLYBS, DLYBCT refer to the fields of the
Chip Select Register corresponding to the Current Chip Select
- When NPCS is 0xF, CSAAT is 0.
1
TDRE ?
0
1
PS ?
0
1
0
Fixed
peripheral
PS ?
1
Fixed
peripheral
0
CSAAT ?
Variable
peripheral
Variable
peripheral
SPI_TDR(PCS)
= NPCS ?
no
NPCS = SPI_TDR(PCS)
NPCS = SPI_MR(PCS)
yes
SPI_MR(PCS)
= NPCS ?
no
NPCS = 0xF
NPCS = 0xF
Delay DLYBCS
Delay DLYBCS
NPCS = SPI_TDR(PCS)
NPCS = SPI_MR(PCS),
SPI_TDR(PCS)
Delay DLYBS
Serializer = SPI_TDR(TD)
TDRE = 1
Data Transfer
SPI_RDR(RD) = Serializer
RDRF = 1
Delay DLYBCT
0
TDRE ?
1
1
CSAAT ?
0
NPCS = 0xF
Delay DLYBCS
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31.6.3.3
Clock Generation
The SPI Baud rate clock is generated by dividing the Master Clock (MCK) , by a value
between 1 and 255.
This allows a maximum operating baud rate at up to Master Clock and a minimum operating
baud rate of MCK divided by 255.
Programming the SCBR field at 0 is forbidden. Triggering a transfer while SCBR is at 0 can
lead to unpredictable results.
At reset, SCBR is 0 and the user has to program it at a valid value before performing the first
transfer.
The divisor can be defined independently for each chip select, as it has to be programmed in
the SCBR field of the Chip Select Registers. This allows the SPI to automatically adapt the
baud rate for each interfaced peripheral without reprogramming.
31.6.3.4
Transfer Delays
Figure 31-7 shows a chip select transfer change and consecutive transfers on the same chip
select. Three delays can be programmed to modify the transfer waveforms:
• The delay between chip selects, programmable only once for all the chip selects by writing
the DLYBCS field in the Mode Register. Allows insertion of a delay between release of one
chip select and before assertion of a new one.
• The delay before SPCK, independently programmable for each chip select by writing the
field DLYBS. Allows the start of SPCK to be delayed after the chip select has been
asserted.
• The delay between consecutive transfers, independently programmable for each chip
select by writing the DLYBCT field. Allows insertion of a delay between two transfers
occurring on the same chip select
These delays allow the SPI to be adapted to the interfaced peripherals and their speed and
bus release time.
Figure 31-7. Programmable Delays
Chip Select 1
Chip Select 2
SPCK
DLYBCS
31.6.3.5
DLYBS
DLYBCT
DLYBCT
Peripheral Selection
The serial peripherals are selected through the assertion of the NPCS0 to NPCS3 signals. By
default, all the NPCS signals are high before and after each transfer.
The peripheral selection can be performed in two different ways:
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• Fixed Peripheral Select: SPI exchanges data with only one peripheral
• Variable Peripheral Select: Data can be exchanged with more than one peripheral
Fixed Peripheral Select is activated by writing the PS bit to zero in SPI_MR (Mode Register).
In this case, the current peripheral is defined by the PCS field in SPI_MR and the PCS field in
the SPI_TDR has no effect.
Variable Peripheral Select is activated by setting PS bit to one. The PCS field in SPI_TDR is
used to select the current peripheral. This means that the peripheral selection can be defined
for each new data.
The Fixed Peripheral Selection allows buffer transfers with a single peripheral. Using the PDC
is an optimal means, as the size of the data transfer between the memory and the SPI is either
8 bits or 16 bits. However, changing the peripheral selection requires the Mode Register to be
reprogrammed.
The Variable Peripheral Selection allows buffer transfers with multiple peripherals without
reprogramming the Mode Register. Data written in SPI_TDR is 32 bits wide and defines the
real data to be transmitted and the peripheral it is destined to. Using the PDC in this mode
requires 32-bit wide buffers, with the data in the LSBs and the PCS and LASTXFER fields in
the MSBs, however the SPI still controls the number of bits (8 to16) to be transferred through
MISO and MOSI lines with the chip select configuration registers. This is not the optimal
means in term of memory size for the buffers, but it provides a very effective means to
exchange data with several peripherals without any intervention of the processor.
31.6.3.6
Peripheral Chip Select Decoding
The user can program the SPI to operate with up to 15 peripherals by decoding the four Chip
Select lines, NPCS0 to NPCS3 with an external logic. This can be enabled by writing the PCSDEC bit at 1 in the Mode Register (SPI_MR).
When operating without decoding, the SPI makes sure that in any case only one chip select
line is activated, i.e. driven low at a time. If two bits are defined low in a PCS field, only the lowest numbered chip select is driven low.
When operating with decoding, the SPI directly outputs the value defined by the PCS field of
either the Mode Register or the Transmit Data Register (depending on PS).
As the SPI sets a default value of 0xF on the chip select lines (i.e. all chip select lines at 1)
when not processing any transfer, only 15 peripherals can be decoded.
The SPI has only four Chip Select Registers, not 15. As a result, when decoding is activated,
each chip select defines the characteristics of up to four peripherals. As an example,
SPI_CRS0 defines the characteristics of the externally decoded peripherals 0 to 3, corresponding to the PCS values 0x0 to 0x3. Thus, the user has to make sure to connect
compatible peripherals on the decoded chip select lines 0 to 3, 4 to 7, 8 to 11 and 12 to 14.
31.6.3.7
454
Peripheral Deselection
When operating normally, as soon as the transfer of the last data written in SPI_TDR is completed, the NPCS lines all rise. This might lead to runtime error if the processor is too long in
responding to an interrupt, and thus might lead to difficulties for interfacing with some serial
peripherals requiring the chip select line to remain active during a full set of transfers.
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To facilitate interfacing with such devices, the Chip Select Register can be programmed with
the CSAAT bit (Chip Select Active After Transfer) at 1. This allows the chip select lines to
remain in their current state (low = active) until transfer to another peripheral is required.
Figure 31-8 shows different peripheral deselection cases and the effect of the CSAAT bit.
Figure 31-8. Peripheral Deselection
CSAAT = 0
TDRE
NPCS[0..3]
CSAAT = 1
DLYBCT
DLYBCT
A
A
A
A
DLYBCS
A
DLYBCS
PCS = A
PCS = A
Write SPI_TDR
TDRE
NPCS[0..3]
DLYBCT
DLYBCT
A
A
A
A
DLYBCS
A
DLYBCS
PCS=A
PCS = A
Write SPI_TDR
TDRE
NPCS[0..3]
DLYBCT
DLYBCT
A
B
A
B
DLYBCS
PCS = B
DLYBCS
PCS = B
Write SPI_TDR
31.6.3.8
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. NPCS0, MOSI, MISO and SPCK
must be configured in open drain through the PIO controller, so that external pull up resistors
are needed to guarantee high level.
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 automatically disabled until re-enabled by writing the SPIEN bit in the SPI_CR
(Control Register) at 1.
By default, the Mode Fault detection circuitry is enabled. The user can disable Mode Fault
detection by setting the MODFDIS bit in the SPI Mode Register (SPI_MR).
455
6249B–ATARM–14-Dec-06
31.6.4
SPI Slave Mode
When operating in Slave Mode, the SPI processes data bits on the clock provided on the SPI
clock pin (SPCK).
The SPI waits for NSS to go active before receiving the serial clock from an external master.
When NSS falls, the clock is validated on the serializer, which processes the number of bits
defined by the BITS field of the Chip Select Register 0 (SPI_CSR0). These bits are processed
following a phase and a polarity defined respectively by the NCPHA and CPOL bits of the
SPI_CSR0. Note that BITS, CPOL and NCPHA of the other Chip Select Registers have no
effect when the SPI is programmed in Slave Mode.
The bits are shifted out on the MISO line and sampled on the MOSI line.
When all the bits are processed, the received data is transferred in the Receive Data Register
and the RDRF bit rises. If RDRF is already high when the data is transferred, the Overrun bit
rises and the data transfer to SPI_RDR is aborted.
When a transfer starts, the data shifted out is the data present in the Shift Register. If no data
has been written in the Transmit Data Register (SPI_TDR), the last data received is transferred. If no data has been received since the last reset, all bits are transmitted low, as the
Shift Register resets at 0.
When a first data is written in SPI_TDR, it is transferred immediately in the Shift Register and
the TDRE bit rises. If new data is written, it remains in SPI_TDR until a transfer occurs, i.e.
NSS falls and there is a valid clock on the SPCK pin. When the transfer occurs, the last data
written in SPI_TDR is transferred in the Shift Register and the TDRE bit rises. This enables
frequent updates of critical variables with single transfers.
Then, a new data is loaded in the Shift Register from the Transmit Data Register. In case no
character is ready to be transmitted, i.e. no character has been written in SPI_TDR since the
last load from SPI_TDR to the Shift Register, the Shift Register is not modified and the last
received character is retransmitted.
Figure 31-9 shows a block diagram of the SPI when operating in Slave Mode.
Figure 31-9. Slave Mode Functional Block Diagram
SPCK
NSS
SPI
Clock
SPIEN
SPIENS
SPIDIS
SPI_CSR0
SPI_RDR
BITS
NCPHA
CPOL
MOSI
LSB
RDRF
OVRES
RD
MSB
Shift Register
MISO
SPI_TDR
TD
456
TDRE
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AT91SAM9263 Preliminary
31.7
Serial Peripheral Interface (SPI) User Interface
Table 31-3.
SPI Register Mapping
Offset
Register
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
0x004C - 0x00F8
Reserved
–
–
–
0x004C - 0x00FC
Reserved
–
–
–
0x100 - 0x124
Reserved for the PDC
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6249B–ATARM–14-Dec-06
31.7.1
SPI Control Register
Name:
SPI_CR
Access Type:
Write-only
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
LASTXFER
23
22
21
20
19
18
17
16
–
–
–
–
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
–
–
–
–
–
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.
As soon as SPIDIS is set, SPI finishes its tranfer.
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.
The SPI is in slave mode after software reset.
PDC channels are not affected by software reset.
• LASTXFER: Last Transfer
0 = No effect.
1 = The current NPCS will be deasserted after the character written in TD has been transferred. When CSAAT is set, this
allows to close the communication with the current serial peripheral by raising the corresponding NPCS line as soon as TD
transfer has completed.
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31.7.2
SPI Mode Register
Name:
SPI_MR
Access Type:
Read/Write
31
30
29
28
27
26
19
18
25
24
17
16
DLYBCS
23
22
21
20
–
–
–
–
15
14
13
12
11
10
9
8
–
–
–
–
–
–
–
–
3
7
6
5
4
LLB
–
–
MODFDIS
PCS
2
1
0
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 15 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 15 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 14.
• MODFDIS: Mode Fault Detection
0 = Mode fault detection is enabled.
1 = Mode fault detection is disabled.
• LLB: Local Loopback Enable
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. (MISO is internally connected on
MOSI.)
• 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)
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6249B–ATARM–14-Dec-06
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 will be inserted by default.
Otherwise, the following equation determines the delay:
DLYBCS
Delay Between Chip Selects = ----------------------MCK
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31.7.3
SPI Receive Data Register
Name:
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.
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6249B–ATARM–14-Dec-06
31.7.4
SPI Transmit Data Register
Name:
SPI_TDR
Access Type:
Write-only
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
LASTXFER
23
22
21
20
19
18
17
16
–
–
–
–
15
14
13
12
PCS
11
10
9
8
3
2
1
0
TD
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
• LASTXFER: Last Transfer
0 = No effect.
1 = The current NPCS will be deasserted after the character written in TD has been transferred. When CSAAT is set, this
allows to close the communication with the current serial peripheral by raising the corresponding NPCS line as soon as TD
transfer has completed.
This field is only used if Variable Peripheral Select is active (PS = 1).
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31.7.5
SPI Status Register
Name:
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
–
–
–
–
–
–
TXEMPTY
NSSR
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(1) or SPI_RNCR(1).
1 = The Receive Counter Register has reached 0 since the last write in SPI_RCR(1) or SPI_RNCR(1).
• ENDTX: End of TX buffer
0 = The Transmit Counter Register has not reached 0 since the last write in SPI_TCR(1) or SPI_TNCR(1).
1 = The Transmit Counter Register has reached 0 since the last write in SPI_TCR(1) or SPI_TNCR(1).
• RXBUFF: RX Buffer Full
0 = SPI_RCR(1) or SPI_RNCR(1) has a value other than 0.
1 = Both SPI_RCR(1) and SPI_RNCR(1) have a value of 0.
• TXBUFE: TX Buffer Empty
0 = SPI_TCR(1) or SPI_TNCR(1) has a value other than 0.
1 = Both SPI_TCR(1) and SPI_TNCR(1) have a value of 0.
• NSSR: NSS Rising
0 = No rising edge detected on NSS pin since last read.
1 = A rising edge occurred on NSS pin since last read.
• TXEMPTY: Transmission Registers Empty
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6249B–ATARM–14-Dec-06
0 = As soon as data is written in SPI_TDR.
1 = SPI_TDR and internal shifter are empty. If a transfer delay has been defined, TXEMPTY is set after the completion of
such delay.
• SPIENS: SPI Enable Status
0 = SPI is disabled.
1 = SPI is enabled.
Note:
464
1. SPI_RCR, SPI_RNCR, SPI_TCR, SPI_TNCR are physically located in the PDC.
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
31.7.6
SPI Interrupt Enable Register
Name:
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
–
–
–
–
–
–
TXEMPTY
NSSR
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
• TXEMPTY: Transmission Registers Empty Enable
• NSSR: NSS Rising Interrupt Enable
0 = No effect.
1 = Enables the corresponding interrupt.
465
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31.7.7
SPI Interrupt Disable Register
Name:
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
–
–
–
–
–
–
TXEMPTY
NSSR
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
• TXEMPTY: Transmission Registers Empty Disable
• NSSR: NSS Rising Interrupt Disable
0 = No effect.
1 = Disables the corresponding interrupt.
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31.7.8
SPI Interrupt Mask Register
Name:
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
–
–
–
–
–
–
TXEMPTY
NSSR
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
• TXEMPTY: Transmission Registers Empty Mask
• NSSR: NSS Rising Interrupt Mask
0 = The corresponding interrupt is not enabled.
1 = The corresponding interrupt is enabled.
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31.7.9
SPI Chip Select Register
Name:
SPI_CSR0... SPI_CSR3
Access Type:
Read/Write
31
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
CSAAT
–
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.
• CSAAT: Chip Select Active After Transfer
0 = The Peripheral Chip Select Line rises as soon as the last transfer is achieved.
1 = The Peripheral Chip Select does not rise after the last transfer is achieved. It remains active until a new transfer is
requested on a different chip select.
• BITS: Bits Per Transfer
The BITS field determines the number of data bits transferred. Reserved values should not be used.
BITS
Bits Per Transfer
0000
8
0001
9
0010
10
0011
11
0100
12
0101
13
0110
14
0111
15
1000
16
1001
Reserved
1010
Reserved
1011
Reserved
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BITS
Bits Per Transfer
1100
Reserved
1101
Reserved
1110
Reserved
1111
Reserved
• 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 1 to 255 in the SCBR field. The following equations determine the SPCK baud
rate:
MCK
SPCK Baudrate = --------------SCBR
Programming the SCBR field at 0 is forbidden. Triggering a transfer while SCBR is at 0 can lead to unpredictable results.
At reset, SCBR is 0 and the user has to program it at a valid value before performing the first transfer.
• 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:
Delay Before SPCK = 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, no delay between consecutive transfers is inserted and the clock keeps its duty cycle over the
character transfers.
Otherwise, the following equation determines the delay:
32 × DLYBCT
Delay Between Consecutive Transfers = ------------------------------------MCK
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32. Two-wire Interface (TWI)
32.1
Description
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 byteoriented 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.
32.2
Block Diagram
Figure 32-1. Block Diagram
APB Bridge
TWCK
PIO
PMC
MCK
TWD
Two-wire
Interface
TWI
Interrupt
32.3
AIC
Application Block Diagram
Figure 32-2. Application Block Diagram
VDD
R
Host with
TWI
Interface
R
TWD
TWCK
AT24LC16
U1
AT24LC16
U2
LCD Controller
U3
Slave 1
Slave 2
Slave 3
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6249B–ATARM–14-Dec-06
32.3.1
I/O Lines Description
Table 32-1.
32.4
32.4.1
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 32-2 on page 471). When the bus is free, both lines
are high. The output stages of devices connected to the bus must have an open-drain or 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.
32.4.2
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.
32.4.3
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.
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32.5
32.5.1
Functional Description
Transfer format
The data put on the TWD line must be 8 bits long. Data is transferred MSB first; each byte
must be followed by an acknowledgement. The number of bytes per transfer is unlimited (see
Figure 32-4 on page 473).
Each transfer begins with a START condition and terminates with a STOP condition (see Figure 32-3 on page 473).
• A high-to-low transition on the TWD line while TWCK is high defines the START condition.
• A low-to-high transition on the TWD line while TWCK is high defines a STOP condition.
Figure 32-3.
START and STOP Conditions
TWD
TWCK
Start
Stop
Figure 32-4. Transfer Format
TWD
TWCK
Start
32.5.2
Address
R/W
Ack
Data
Ack
Data
Ack
Stop
Modes of Operation
The TWI has two modes of operation:
• 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.
32.5.3
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
473
6249B–ATARM–14-Dec-06
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 32-6 below). 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, IADRSZ must be set to 0. For a
slave address higher than 7 bits, the user must configure the address size (IADRSZ) and set
the other slave address bits in the internal address register (TWI_IADR).
Figure 32-5. 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 32-6. 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 32-7. Master Read with One, Two or Three Bytes Internal Address and One Data Byte
Three bytes internal address
TWD
S
DADR
W
A
IADR(23:16)
A
IADR(15:8)
A
IADR(7:0)
A
S
DADR
R
A
DATA
N
P
Two bytes internal address
TWD
S
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
One byte internal address
TWD
474
S
DADR
DADR
DATA
N
P
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Figure 32-8. 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
DATA
N
P
TXCOMP
Write START Bit
Write STOP Bit
RXRDY
Read RHR
Read RHR
• S = Start
• P = Stop
• W = Write
• R = Read
• A = Acknowledge
• N = Not Acknowledge
• DADR= Device Address
• IADR = Internal Address
Figure 32-9 below shows a byte write to an Atmel AT24LC512 EEPROM. This demonstrates
the use of internal addresses to access the device.
Figure 32-9.
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
LR A
S / C
BW K
M
S
B
A
C
K
LA
SC
BK
A
C
K
475
6249B–ATARM–14-Dec-06
32.5.4
Read/Write Flowcharts
The following flowcharts shown in Figure 32-10 on page 476 and in Figure 32-11 on page 477
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.
Figure 32-10. TWI Write in Master Mode
START
Set TWI clock:
TWI_CWGR = clock
Set the control register:
- Master enable
TWI_CR = MSEN
Set the Master Mode register:
- Device slave address
- Internal address size
- Transfer direction bit
Write ==> bit MREAD = 0
Internal address size = 0?
Set theinternal address
TWI_IADR = address
Yes
Load transmit register
TWI_THR = Data to send
Start the transfer
TWI_CR = START
Read status register
TWI_THR = data to send
TXRDY = 0?
Yes
Data to send?
Yes
Stop the transfer
TWI_CR = STOP
Read status register
TXCOMP = 0?
Yes
END
476
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Figure 32-11. TWI Read in Master Mode
START
Set TWI clock:
TWI_CWGR = clock
Set the control register:
- Master enable
- Slave disable
TWI_CR = 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 = START
Read status register
RXRDY = 0?
Yes
Data to read?
Yes
Stop the transfer
TWI_CR = STOP
Read status register
TXCOMP = 0?
Yes
END
477
6249B–ATARM–14-Dec-06
32.6
TWI User Interface
32.6.1
Register Mapping
Table 32-2.
Two-wire Interface (TWI) User Interface
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
–
–
–
0x0038 - 0x00FC
478
Reserved
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
32.6.2
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 they contain
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.
479
6249B–ATARM–14-Dec-06
32.6.3
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.
480
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
32.6.4
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.
32.6.5
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 SCL low period is defined as follows:
T low = ( ( CLDIV × 2
CKDIV
) + 3 ) × T MCK
• CHDIV: Clock High Divider
The SCL high period is defined as follows:
T high = ( ( CHDIV × 2
CKDIV
) + 3 ) × T MCK
• CKDIV: Clock Divider
The CKDIV is used to increase both SCL high and low periods.
32.6.6
TWI Status Register
Register Name:
TWI_SR
481
6249B–ATARM–14-Dec-06
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
–
6
–
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 shift 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 theTWI_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).
• 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.
482
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
32.6.7
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
–
6
–
5
–
4
–
3
–
2
TXRDY
1
RXRDY
0
TXCOMP
• TXCOMP: Transmission Completed
• RXRDY: Receive Holding Register Ready
• TXRDY: Transmit Holding Register Ready
• NACK: Not Acknowledge
0 = No effect.
1 = Enables the corresponding interrupt.
32.6.8
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
–
6
–
5
–
4
–
3
–
2
TXRDY
1
RXRDY
0
TXCOMP
• TXCOMP: Transmission Completed
• RXRDY: Receive Holding Register Ready
• TXRDY: Transmit Holding Register Ready
• NACK: Not Acknowledge
0 = No effect.
1 = Disables the corresponding interrupt.
483
6249B–ATARM–14-Dec-06
32.6.9
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
–
6
–
5
–
4
–
3
–
2
TXRDY
1
RXRDY
0
TXCOMP
• TXCOMP: Transmission Completed
• RXRDY: Receive Holding Register Ready
• TXRDY: Transmit Holding Register Ready
• NACK: Not Acknowledge
0 = The corresponding interrupt is disabled.
1 = The corresponding interrupt is enabled.
32.6.10
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
484
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
32.6.11
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
485
6249B–ATARM–14-Dec-06
486
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
33. Universal Synchronous/Asynchronous Receiver/Transmitter
33.1
Description
The Universal Synchronous Asynchronous Receiver Transmitter (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. Multidrop communications are also supported through address bit handling in reception and transmission.
The USART features three test modes: remote loopback, local loopback and automatic echo.
The USART supports specific operating modes providing interfaces on RS485 buses, with
ISO7816 T = 0 or T = 1 smart card slots and infrared transceivers. 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.
487
6249B–ATARM–14-Dec-06
33.2
Block Diagram
Figure 33-1. USART Block Diagram
Peripheral DMA
Controller
Channel
Channel
PIO
Controller
USART
RXD
Receiver
RTS
AIC
TXD
USART
Interrupt
Transmitter
CTS
PMC
MCK
DIV
Baud Rate
Generator
SCK
MCK/DIV
User Interface
SLCK
APB
488
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
33.3
Application Block Diagram
Figure 33-2. Application Block Diagram
IrLAP
PPP
Serial
Driver
Field Bus
Driver
EMV
Driver
IrDA
Driver
USART
33.4
RS232
Drivers
RS485
Drivers
Serial
Port
Differential
Bus
Smart
Card
Slot
IrDA
Transceivers
I/O Lines Description
Table 33-1.
I/O Line Description
Name
Description
Type
Active Level
SCK
Serial Clock
I/O
TXD
Transmit Serial Data
I/O
RXD
Receive Serial Data
Input
CTS
Clear to Send
Input
Low
RTS
Request to Send
Output
Low
489
6249B–ATARM–14-Dec-06
33.5
33.5.1
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.
To prevent the TXD line from falling when the USART is disabled, the use of an internal pull up
is mandatory.
33.5.2
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.
33.5.3
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.
490
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
33.6
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 break management
– Optional multidrop serial communication
• High-speed 5- to 9-bit full-duplex synchronous serial communication
– MSB- or LSB-first
– 1 or 2 stop bits
– Parity even, odd, marked, space or none
– By 8 or by 16 over-sampling frequency
– Optional hardware handshaking
– Optional break management
– Optional multidrop serial communication
• RS485 with driver control signal
• ISO7816, T0 or T1 protocols for interfacing with smart cards
– NACK handling, error counter with repetition and iteration limit
• InfraRed IrDA Modulation and Demodulation
• Test modes
– Remote loopback, local loopback, automatic echo
33.6.1
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.
491
6249B–ATARM–14-Dec-06
Figure 33-3. Baud Rate Generator
USCLKS
MCK
MCK/DIV
SCK
Reserved
CD
CD
SCK
0
1
16-bit Counter
2
FIDI
>1
3
1
0
0
0
SYNC
OVER
Sampling
Divider
0
Baud Rate
Clock
1
1
SYNC
Sampling
Clock
USCLKS = 3
33.6.1.1
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.
Baud Rate Calculation Example
Table 33-2 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 33-2.
492
Baud Rate Example (OVER = 0)
Source Clock
Expected Baud
Rate
MHz
Bit/s
3 686 400
38 400
6.00
6
38 400.00
0.00%
4 915 200
38 400
8.00
8
38 400.00
0.00%
5 000 000
38 400
8.14
8
39 062.50
1.70%
7 372 800
38 400
12.00
12
38 400.00
0.00%
8 000 000
38 400
13.02
13
38 461.54
0.16%
12 000 000
38 400
19.53
20
37 500.00
2.40%
12 288 000
38 400
20.00
20
38 400.00
0.00%
Calculation Result
CD
Actual Baud Rate
Error
Bit/s
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Table 33-2.
Baud Rate Example (OVER = 0) (Continued)
Source Clock
Expected Baud
Rate
Calculation Result
CD
Actual Baud Rate
Error
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%
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
33.6.1.2
Fractional Baud Rate in Asynchronous Mode
The Baud Rate generator previously defined is subject to the following limitation: the output frequency changes by only integer multiples of the reference frequency. An approach to this
problem is to integrate a fractional N clock generator that has a high resolution. The generator
architecture is modified to obtain Baud Rate changes by a fraction of the reference source clock.
This fractional part is programmed with the FP field in the Baud Rate Generator Register
(US_BRGR). If FP is not 0, the fractional part is activated. The resolution is one eighth of the
clock divider. This feature is only available when using USART normal mode. The fractional
Baud Rate is calculated using the following formula:
SelectedClock
Baudrate = ---------------------------------------------------------------⎛ 8 ( 2 – Over ) ⎛ CD + FP
⎞
⎞
-------⎠ ⎠
⎝
⎝
8
The modified architecture is presented below:
493
6249B–ATARM–14-Dec-06
Figure 33-4. Fractional Baud Rate Generator
FP
USCLKS
CD
Modulus
Control
FP
MCK
MCK/DIV
SCK
Reserved
CD
SCK
0
1
16-bit Counter
2
3
glitch-free
logic
1
0
FIDI
>1
0
0
SYNC
OVER
Sampling
Divider
0
Baud Rate
Clock
1
1
SYNC
USCLKS = 3
33.6.1.3
Sampling
Clock
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.
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.
33.6.1.4
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)
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AT91SAM9263 Preliminary
Di is a binary value encoded on a 4-bit field, named DI, as represented in Table 33-3.
Table 33-3.
Binary and Decimal Values for Di
DI field
0001
0010
0011
0100
0101
0110
1000
1001
1
2
4
8
16
32
12
20
Di (decimal)
Fi is a binary value encoded on a 4-bit field, named FI, as represented in Table 33-4.
Table 33-4.
Binary and Decimal Values for Fi
FI field
0000
0001
0010
0011
0100
0101
0110
1001
1010
1011
1100
1101
Fi (decimal
372
372
558
744
1116
1488
1860
512
768
1024
1536
2048
Table 33-5 shows the resulting Fi/Di Ratio, which is the ratio between the ISO7816 clock and the
baud rate clock.
Table 33-5.
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
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 33-5 shows the relation between the Elementary Time Unit, corresponding to a bit time,
and the ISO 7816 clock.
495
6249B–ATARM–14-Dec-06
Figure 33-5. Elementary Time Unit (ETU)
FI_DI_RATIO
ISO7816 Clock Cycles
ISO7816 Clock
on SCK
ISO7816 I/O Line
on TXD
1 ETU
33.6.2
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
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 timeguard is programmed, it is handled normally.
33.6.3
33.6.3.1
Synchronous and Asynchronous Modes
Transmitter Operations
The transmitter performs the same in both synchronous and asynchronous operating modes
(SYNC = 0 or SYNC = 1). One start bit, up to 9 data bits, one optional parity bit and up to two
stop bits are successively shifted out on the TXD pin at each falling edge of the programmed
serial clock.
The number of data bits is selected by the CHRL field and the MODE 9 bit in the Mode Register
(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.
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Figure 33-6. 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.
Figure 33-7. 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
33.6.3.2
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. For the synchronization
mechanism only, the number of stop bits has no effect on the receiver as it considers only one
stop bit, regardless of the field NBSTOP, so that resynchronization between the receiver and the
497
6249B–ATARM–14-Dec-06
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 33-8 and Figure 33-9 illustrate start detection and character reception when USART
operates in asynchronous mode.
Figure 33-8. 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 33-9. 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
33.6.3.3
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 33-10 illustrates a character reception in synchronous mode.
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Figure 33-10. 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
33.6.3.4
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 33-11. 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
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6249B–ATARM–14-Dec-06
33.6.3.5
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 Multidrop mode, see “Multidrop Mode” on
page 501. Even and odd parity bit generation and error detection are supported.
If even parity is selected, the parity generator of the transmitter drives the parity bit at 0 if a number of 1s in the character data bit is even, and at 1 if the number of 1s is odd. Accordingly, the
receiver parity checker counts the number of received 1s and reports a parity error if the sampled parity bit does not correspond. If odd parity is selected, the parity generator of the
transmitter drives the parity bit at 1 if a number of 1s in the character data bit is even, and at 0 if
the number of 1s is odd. Accordingly, the receiver parity checker counts the number of received
1s and reports a parity error if the sampled parity bit does not correspond. If the mark parity is
used, the parity generator of the transmitter drives the parity bit at 1 for all characters. The
receiver parity checker reports an error if the parity bit is sampled at 0. If the space parity is
used, the parity generator of the transmitter drives the parity bit at 0 for all characters. The
receiver parity checker reports an error if the parity bit is sampled at 1. If parity is disabled, the
transmitter does not generate any parity bit and the receiver does not report any parity error.
Table 33-6 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.
Table 33-6.
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 33-12 illustrates the parity bit status setting and clearing.
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Figure 33-12. 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
33.6.3.6
Multidrop Mode
If the PAR field in the Mode Register (US_MR) is programmed to the value 0x6 or 0x07, the
USART runs in Multidrop Mode. This mode differentiates the data characters and the address
characters. Data is transmitted with the parity bit at 0 and addresses are transmitted with the
parity bit at 1.
If the USART is configured in multidrop mode, the receiver sets the PARE parity error bit when
the parity bit is high and the transmitter is able to send a character with the parity bit high when
the Control Register is written with the SENDA bit at 1.
To handle parity error, the PARE bit is cleared when the Control Register is written with the bit
RSTSTA at 1.
The transmitter sends an address byte (parity bit set) when SENDA is written to 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.
33.6.3.7
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 33-13, 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.
501
6249B–ATARM–14-Dec-06
Figure 33-13. 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 33-7 indicates the maximum length of a timeguard period that the transmitter can handle
in relation to the function of the Baud Rate.
Table 33-7.
33.6.3.8
Maximum Timeguard Length Depending on Baud Rate
Baud Rate
Bit time
Timeguard
Bit/sec
µs
ms
1 200
833
212.50
9 600
104
26.56
14400
69.4
17.71
19200
52.1
13.28
28800
34.7
8.85
33400
29.9
7.63
56000
17.9
4.55
57600
17.4
4.43
115200
8.7
2.21
Receiver Time-out
The Receiver Time-out provides support in handling variable-length frames. This feature detects
an idle condition on the RXD line. When a time-out is detected, the bit TIMEOUT in the Channel
Status Register (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. Then, the user
can either:
• Stop the counter clock until a new character is received. This is performed by writing the
Control Register (US_CR) with the STTTO (Start Time-out) bit at 1. In this case, the idle state
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AT91SAM9263 Preliminary
on RXD before a new character is received will not provide a time-out. This prevents having
to handle an interrupt before a character is received and allows waiting for the next idle state
on RXD after a frame is received.
• Obtain an interrupt while no character is received. This is performed by writing US_CR with
the RETTO (Reload and Start Time-out) bit at 1. If RETTO is performed, the counter starts
counting down immediately from the value TO. This enables generation of a periodic interrupt
so that a user time-out can be handled, for example when no key is pressed on a keyboard.
If STTTO is performed, the counter clock is stopped until a first character is received. The idle
state on RXD before the start of the frame does not provide a time-out. This prevents having to
obtain a periodic interrupt and enables a wait of the end of frame when the idle state on RXD is
detected.
If RETTO is performed, the counter starts counting down immediately from the value TO. This
enables generation of a periodic interrupt so that a user time-out can be handled, for example
when no key is pressed on a keyboard.
Figure 33-14 shows the block diagram of the Receiver Time-out feature.
Figure 33-14. Receiver Time-out Block Diagram
TO
Baud Rate
Clock
1
D
Q
Clock
16-bit Time-out
Counter
16-bit
Value
=
STTTO
Clear
Character
Received
Load
TIMEOUT
0
RETTO
Table 33-8 gives the maximum time-out period for some standard baud rates.
Table 33-8.
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
503
6249B–ATARM–14-Dec-06
Table 33-8.
33.6.3.9
Maximum Time-out Period (Continued)
Baud Rate
Bit Time
Time-out
56000
18
1 170
57600
17
1 138
200000
5
328
Framing Error
The receiver is capable of detecting framing errors. A framing error happens when the stop bit of
a received character is detected at level 0. This can occur if the receiver and the transmitter are
fully desynchronized.
A framing error is reported on the FRAME bit of the Channel Status Register (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 33-15. 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
33.6.3.10
Transmit Break
The user can request the transmitter to generate a break condition on the TXD line. A break condition drives the TXD line low during at least one complete character. It appears the same as a
0x00 character sent with the parity and the stop bits at 0. However, the transmitter holds the
TXD line at least during one character until the user requests the break condition to be removed.
A break is transmitted by writing the Control Register (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.
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AT91SAM9263 Preliminary
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 33-16 illustrates the effect of both the Start Break (STTBRK) and Stop Break (STPBRK)
commands on the TXD line.
Figure 33-16. 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
33.6.3.11
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.
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.
33.6.3.12
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 33-17.
505
6249B–ATARM–14-Dec-06
Figure 33-17. 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 33-18 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 33-18. Receiver Behavior when Operating with Hardware Handshaking
RXD
RXEN = 1
RXDIS = 1
Write
US_CR
RTS
RXBUFF
Figure 33-19 shows how the transmitter operates if hardware handshaking is enabled. The CTS
pin disables the transmitter. If a character is being processing, the transmitter is disabled only
after the completion of the current character and transmission of the next character happens as
soon as the pin CTS falls.
Figure 33-19. Transmitter Behavior when Operating with Hardware Handshaking
CTS
TXD
506
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AT91SAM9263 Preliminary
33.6.4
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.
33.6.4.1
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 491).
The USART connects to a smart card as shown in Figure 33-20. 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 33-20. 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. Parity Bit (PAR) can be used to transmit in normal or inverse mode. Refer to
“USART Mode Register” on page 518 and “PAR: Parity Type” on page 519.
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).
33.6.4.2
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 33-21.
507
6249B–ATARM–14-Dec-06
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 33-22. 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 33-21. 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 33-22. 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 set, 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
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.
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
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.
33.6.4.3
33.6.5
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 33-23. The modulator and demodulator are compliant
with the IrDA specification version 1.1 and support data transfer speeds ranging from 2.4 Kb/s to
115.2 Kb/s.
The USART IrDA mode is enabled by setting the 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 33-23. Connection to IrDA Transceivers
USART
IrDA
Transceivers
Receiver
Demodulator
RXD
Transmitter
Modulator
TXD
RX
TX
The receiver and the transmitter must be enabled or disabled according to the direction of the
transmission to be managed.
509
6249B–ATARM–14-Dec-06
33.6.5.1
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 33-9.
Table 33-9.
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 33-24 shows an example of character transmission.
Figure 33-24. IrDA Modulation
Start
Bit
Transmitter
Output
0
Stop
Bit
Data Bits
1
0
1
0
1
0
1
0
1
TXD
3
16 Bit Period
Bit Period
33.6.5.2
IrDA Baud Rate
Table 33-10 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 33-10. IrDA Baud Rate Error
Peripheral Clock
510
Baud Rate
CD
Baud Rate Error
Pulse Time
3 686 400
115 200
2
0.00%
1.63
20 000 000
115 200
11
1.38%
1.63
32 768 000
115 200
18
1.25%
1.63
40 000 000
115 200
22
1.38%
1.63
3 686 400
57 600
4
0.00%
3.26
20 000 000
57 600
22
1.38%
3.26
32 768 000
57 600
36
1.25%
3.26
40 000 000
57 600
43
0.93%
3.26
3 686 400
38 400
6
0.00%
4.88
20 000 000
38 400
33
1.38%
4.88
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Table 33-10. IrDA Baud Rate Error (Continued)
Peripheral Clock
33.6.5.3
Baud Rate
CD
Baud Rate Error
Pulse Time
32 768 000
38 400
53
0.63%
4.88
40 000 000
38 400
65
0.16%
4.88
3 686 400
19 200
12
0.00%
9.77
20 000 000
19 200
65
0.16%
9.77
32 768 000
19 200
107
0.31%
9.77
40 000 000
19 200
130
0.16%
9.77
3 686 400
9 600
24
0.00%
19.53
20 000 000
9 600
130
0.16%
19.53
32 768 000
9 600
213
0.16%
19.53
40 000 000
9 600
260
0.16%
19.53
3 686 400
2 400
96
0.00%
78.13
20 000 000
2 400
521
0.03%
78.13
32 768 000
2 400
853
0.04%
78.13
IrDA Demodulator
The demodulator is based on the IrDA Receive filter comprised of an 8-bit down counter which is
loaded with the value programmed in 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 33-25 illustrates the operations of the IrDA demodulator.
Figure 33-25. IrDA Demodulator Operations
MCK
RXD
Counter
Value
Receiver
Input
6
5
4 3
Pulse
Rejected
2
6
6
5
4
3
2
1
0
Pulse
Accepted
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.
511
6249B–ATARM–14-Dec-06
33.6.6
RS485 Mode
The USART features the RS485 mode to enable line driver control. While operating in RS485
mode, the USART behaves as though in asynchronous or synchronous mode and configuration
of all the parameters is possible. The difference is that the RTS pin is driven high when the
transmitter is operating. The behavior of the RTS pin is controlled by the TXEMPTY bit. A typical
connection of the USART to a RS485 bus is shown in Figure 33-26.
Figure 33-26. Typical Connection to a 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 to the TXEMPTY bit. Significantly, the RTS pin remains high
when a timeguard is programmed so that the line can remain driven after the last character completion. Figure 33-27 gives an example of the RTS waveform during a character transmission
when the timeguard is enabled.
Figure 33-27. 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
512
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
33.6.7
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.
33.6.7.1
Normal Mode
Normal mode connects the RXD pin on the receiver input and the transmitter output on the TXD
pin.
Figure 33-28. Normal Mode Configuration
RXD
Receiver
TXD
Transmitter
33.6.7.2
Automatic Echo Mode
Automatic echo mode allows bit-by-bit retransmission. When a bit is received on the RXD pin, it
is sent to the TXD pin, as shown in Figure 33-29. 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 33-29. Automatic Echo Mode Configuration
RXD
Receiver
TXD
Transmitter
33.6.7.3
Local Loopback Mode
Local loopback mode connects the output of the transmitter directly to the input of the receiver,
as shown in Figure 33-30. 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 33-30. Local Loopback Mode Configuration
RXD
Receiver
Transmitter
1
TXD
513
6249B–ATARM–14-Dec-06
33.6.7.4
Remote Loopback Mode
Remote loopback mode directly connects the RXD pin to the TXD pin, as shown in Figure 33-31.
The transmitter and the receiver are disabled and have no effect. This mode allows bit-by-bit
retransmission.
Figure 33-31. Remote Loopback Mode Configuration
Receiver
1
RXD
TXD
Transmitter
514
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
33.7
USART User Interface
Table 33-11.
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 - 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
Reserved
–
–
–
Reserved for PDC Registers
–
–
–
0x5C - 0xFC
0x100 - 0x128
515
6249B–ATARM–14-Dec-06
33.7.1
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
–
16
–
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 US_CSR.
• STTBRK: Start Break
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.
516
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
• 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. Resets the status bit TIMEOUT in US_CSR.
• SENDA: Send Address
0: No effect.
1: In Multidrop 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
• RTSEN: Request to Send Enable
0: No effect.
1: Drives the pin RTS to 0.
• RTSDIS: Request to Send Disable
0: No effect.
1: Drives the pin RTS to 1.
517
6249B–ATARM–14-Dec-06
33.7.2
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
Reserved
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
518
Selected Clock
0
0
MCK
0
1
MCK / DIV
1
0
Reserved
1
1
SCK
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
• 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
Multidrop 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.
• MODE9: 9-bit Character Length
0: CHRL defines character length.
519
6249B–ATARM–14-Dec-06
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).
520
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
33.7.3
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
–
17
–
16
–
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
• CTSIC: Clear to Send Input Change Interrupt Enable
521
6249B–ATARM–14-Dec-06
33.7.4
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
–
17
–
16
–
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
• CTSIC: Clear to Send Input Change Interrupt Disable
522
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
33.7.5
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
–
17
–
16
–
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
• CTSIC: Clear to Send Input Change Interrupt Mask
523
6249B–ATARM–14-Dec-06
33.7.6
Name:
USART Channel Status Register
US_CSR
Access Type:
Read-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
CTS
22
–
21
–
20
–
19
CTSIC
18
–
17
–
16
–
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.
• 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.
524
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
• TIMEOUT: Receiver Time-out
0: There has not been a time-out since the last Start Time-out command (STTTO in US_CR) or the Time-out Register is 0.
1: There has been a time-out since the last Start Time-out command (STTTO in US_CR).
• 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.
• 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.
• CTS: Image of CTS Input
0: CTS is at 0.
1: CTS is at 1.
525
6249B–ATARM–14-Dec-06
33.7.7
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
RXSYNH
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.
• RXSYNH: Received Sync
0: Last Character received is a Data.
1: Last Character received is a Command.
33.7.8
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
TXSYNH
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.
• TXSYNH: Sync Field to be transmitted
0: The next character sent is encoded as a data. Start Frame Delimiter is DATA SYNC.
1: The next character sent is encoded as a command. Start Frame Delimiter is COMMAND SYNC.
526
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
33.7.9
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
FP
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
USART_MODE =
ISO7816
OVER = 1
0
1 to 65535
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
• FP: Fractional Part
0: Fractional divider is disabled.
1 - 7: Baudrate resolution, defined by FP x 1/8.
527
6249B–ATARM–14-Dec-06
33.7.10
Name:
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.
528
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
33.7.11
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.
529
6249B–ATARM–14-Dec-06
33.7.12
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.
530
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
33.7.13
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.
531
6249B–ATARM–14-Dec-06
33.7.14
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.
532
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
34. Serial Synchronous Controller (SSC)
34.1
Description
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. The transfers can be programmed to start automatically or on different events detected on the Frame Sync signal.
The SSC’s high-level of programmability and its two dedicated 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:
• CODEC’s in master or slave mode
• DAC through dedicated serial interface, particularly I2S
• Magnetic card reader
533
6249B–ATARM–14-Dec-06
34.2
Block Diagram
Figure 34-1. Block Diagram
System
Bus
APB Bridge
PDC
Peripheral
Bus
TF
TK
PMC
TD
MCK
PIO
SSC Interface
RF
RK
Interrupt Control
RD
SSC Interrupt
34.3
Application Block Diagram
Figure 34-2. Application Block Diagram
OS or RTOS Driver
Power
Management
Interrupt
Management
Test
Management
SSC
Serial AUDIO
534
Codec
Time Slot
Management
Frame
Management
Line Interface
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
34.4
Pin Name List
Table 34-1.
I/O Lines Description
Pin Name
Pin Description
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
34.5
34.5.1
Type
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.
34.5.2
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.
34.5.3
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.
34.6
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.
535
6249B–ATARM–14-Dec-06
Figure 34-3. 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
RD
Receive Shift Register
RX PDC
PDC
Clock Output
Controller
Receive Holding
Register
Receive Sync
Holding Register
Load Shift
AIC
34.6.1
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.
536
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
34.6.1.1
Clock Divider
Figure 34-4. Divided Clock Block Diagram
Clock Divider
SSC_CMR
MCK
/2
12-bit Counter
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 to or greater than 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 of
whether the DIV value is even or odd.
Figure 34-5.
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 34-2.
34.6.1.2
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
537
6249B–ATARM–14-Dec-06
(CKS field) and at the same time Continuous Transmit Clock (CKO field) might lead to unpredictable results.
Figure 34-6. Transmitter Clock Management
TK (pin)
Clock
Output
Tri_state
Controller
MUX
Receiver
Clock
Divider
Clock
Data Transfer
CKO
CKS
34.6.1.3
INV
MUX
Tri-state
Controller
CKI
CKG
Transmitter
Clock
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) can lead to unpredictable
results.
Figure 34-7. Receiver Clock Management
RK (pin)
Tri-state
Controller
MUX
Clock
Output
Transmitter
Clock
Divider
Clock
Data Transfer
CKO
CKS
538
INV
MUX
Tri-state
Controller
CKI
CKG
Receiver
Clock
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
34.6.1.4
Serial Clock Ratio Considerations
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. In
this case, the maximum clock speed allowed on the RK pin is:
– Master Clock divided by 2 if Receiver Frame Synchro is input
– Master Clock divided by 3 if Receiver Frame Synchro is output
In addition, the maximum clock speed allowed on the TK pin is:
– Master Clock divided by 6 if Transmit Frame Synchro is input
– Master Clock divided by 2 if Transmit Frame Synchro is output
34.6.2
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
“Start” on page 540.
The frame synchronization is configured setting the Transmit Frame Mode Register
(SSC_TFMR). See “Frame Sync” on page 542.
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,
the status flag TXRDY is set in SSC_SR and additional data can be loaded in the holding
register.
Figure 34-8. Transmitter Block Diagram
SSC_CR.TXEN
SSC_SR.TXEN
SSC_CR.TXDIS
SSC_TFMR.DATDEF
1
RF
Transmitter Clock
TF
Start
Selector
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
539
6249B–ATARM–14-Dec-06
34.6.3
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
“Start” on page 540.
The frame synchronization is configured setting the Receive Frame Mode Register
(SSC_RFMR). See “Frame Sync” on page 542.
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 depending on the
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 of the RHR register, the status flag OVERUN is set in
SSC_SR and the receiver shift register is transferred in the RHR register.
Figure 34-9. Receiver Block Diagram
SSC_CR.RXEN
SSC_SR.RXEN
SSC_CR.RXDIS
RF
Receiver Clock
TF
Start
Selector
SSC_RFMR.MSBF
SSC_RFMR.DATNB
Receive Shift Register
SSC_RSHR
SSC_RHR
SSC_RFMR.FSLEN
SSC_RFMR.DATLEN
RD
SSC_RCMR.STTDLY
34.6.4
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 TF/RF
• On detection of a low level/high level on TF/RF
• On detection of a level change or an edge on TF/RF
540
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
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).
Moreover, the Receiver can start when data is detected in the bit stream with the Compare
Functions.
Detection on TF/RF input/output is done by the field FSOS of the Transmit/Receive Frame Mode
Register (TFMR/RFMR).
Figure 34-10. 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
STTDLY
BO
X
B1
STTDLY
BO
X
TD
(Output)
B1
STTDLY
TD
(Output)
BO
X
B1
STTDLY
TD
(Output)
TD
(Output)
B1
BO
X
B1
BO
B1
STTDLY
X
B1
BO
BO
B1
STTDLY
Figure 34-11. Receive Pulse/Edge Start Modes
RK
RF
(Input)
Start = Low Level on RF
Start = Falling Edge on RF
Start = High Level on RF
Start = Rising Edge on RF
Start = Level Change on RF
Start = Any Edge on RF
RD
(Input)
RD
(Input)
X
BO
STTDLY
BO
X
B1
STTDLY
BO
X
RD
(Input)
B1
STTDLY
RD
(Input)
BO
X
B1
STTDLY
RD
(Input)
RD
(Input)
B1
BO
X
B1
BO
B1
STTDLY
X
BO
B1
BO
B1
STTDLY
541
6249B–ATARM–14-Dec-06
34.6.5
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.
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.
34.6.5.1
Frame Sync Data
Frame Sync Data transmits or receives a specific tag during the Frame Sync signal.
During the Frame Sync signal, the Receiver can sample the 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 and has a maximum value of 16.
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.
34.6.5.2
34.6.6
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).
Receive Compare Modes
Figure 34-12. Receive Compare Modes
RK
RD
(Input)
CMP0
CMP1
CMP2
CMP3
Ignored
B0
B1
B2
Start
FSLEN
Up to 16 Bits
(4 in This Example)
542
STDLY
DATLEN
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
34.6.6.1
34.6.7
Compare Functions
Length of the comparison patterns (Compare 0, Compare 1) and thus the number of bits they
are compared to is defined by FSLEN, but with a maximum value of 16 bits. Comparison is
always done by comparing the last bits received with the comparison pattern. Compare 0 can be
one start event of the Receiver. In this case, the receiver compares at each new sample the last
bits received at the Compare 0 pattern contained in the Compare 0 Register (SSC_RC0R).
When this start event is selected, the user can program the Receiver to start a new data transfer
either by writing a new Compare 0, or by receiving continuously until Compare 1 occurs. This
selection is done with the bit (STOP) in SSC_RCMR.
Data Format
The data framing format of both the transmitter and the receiver are 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.
543
6249B–ATARM–14-Dec-06
Table 34-3.
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 of words transmitted 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
Most significant bit 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 34-13. Transmit and Receive Frame Format in Edge/Pulse Start Modes
Start
Start
PERIOD
TF/RF
(1)
FSLEN
TD
(If FSDEN = 1)
TD
(If FSDEN = 0)
RD
Sync Data
Default
From SSC_TSHR FromDATDEF
Default
Data
From SSC_THR
Ignored
To SSC_RSHR
STTDLY
From SSC_THR
Default
From SSC_THR
Data
Data
To SSC_RHR
To SSC_RHR
DATLEN
DATLEN
Sync Data
FromDATDEF
Data
Data
From DATDEF
Sync Data
Data
From SSC_THR
Default
From DATDEF
Ignored
Sync Data
DATNB
Note:
544
1. Example of input on falling edge of TF/RF.
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Figure 34-14. Transmit Frame Format in Continuous Mode
Start
Data
TD
Default
Data
From SSC_THR
From SSC_THR
DATLEN
DATLEN
Start: 1. TXEMPTY set to 1
2. Write into the SSC_THR
Note:
1. STTDLY is set to 0. In this example, SSC_THR is loaded twice. FSDEN value has no effect on
the transmission. SyncData cannot be output in continuous mode.
Figure 34-15. Receive Frame Format in Continuous Mode
Start = Enable Receiver
RD
Note:
34.6.8
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.
34.6.9
Interrupt
Most bits in SSC_SR have a corresponding bit in interrupt management registers.
The SSC can be programmed to generate an interrupt when it detects an event. The interrupt is
controlled by writing SSC_IER (Interrupt Enable Register) and SSC_IDR (Interrupt Disable Register) These registers enable and disable, respectively, 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.
545
6249B–ATARM–14-Dec-06
Figure 34-16. 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
34.7
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.
Figure 34-17. Audio Application Block Diagram
Clock SCK
TK
Word Select WS
TF
I2S
RECEIVER
Data SD
SSC
TD
RD
Clock SCK
RF
Word Select WS
RK
Data SD
MSB
LSB
Left Channel
546
MSB
Right Channel
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Figure 34-18. Codec Application Block Diagram
Serial Data Clock (SCLK)
TK
Frame sync (FSYNC)
TF
CODEC
Serial Data Out
TD
SSC
Serial Data In
RD
RF
RK
Serial Data Clock (SCLK)
Frame sync (FSYNC)
First Time Slot
Dstart
Dend
Serial Data Out
Serial Data In
Figure 34-19. Time Slot Application Block Diagram
SCLK
TK
FSYNC
TF
CODEC
First
Time Slot
Data Out
TD
SSC
RD
Data in
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
547
6249B–ATARM–14-Dec-06
34.8
Synchronous Serial Controller (SSC) User Interface
Table 34-4.
Register Mapping
Offset
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
Receive Compare 0 Register
SSC_RC0R
Read/Write
0x0
0x3C
Receive Compare 1 Register
SSC_RC1R
Read/Write
0x0
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 Data Controller (PDC)
–
–
–
0x50-0xFC
0x100- 0x124
548
Register
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
34.8.1
Name:
SSC Control Register
SSC_CR
Access Type:
Write-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
SWRST
14
–
13
–
12
–
11
–
10
–
9
TXDIS
8
TXEN
7
–
6
–
5
–
4
–
3
–
2
–
1
RXDIS
0
RXEN
• RXEN: Receive Enable
0: No effect.
1: Enables Receive if RXDIS is not set.
• RXDIS: Receive Disable
0: No effect.
1: Disables Receive. If a character is currently being received, disables at end of current character reception.
• TXEN: Transmit Enable
0: No effect.
1: Enables Transmit if TXDIS is not set.
• TXDIS: Transmit Disable
0: No effect.
1: Disables Transmit. If a character is currently being transmitted, disables at end of current character transmission.
• SWRST: Software Reset
0: No effect.
1: Performs a software reset. Has priority on any other bit in SSC_CR.
549
6249B–ATARM–14-Dec-06
34.8.2
Name:
SSC Clock Mode Register
SSC_CMR
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
1
0
DIV
3
2
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.
550
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
34.8.3
Name:
SSC Receive Clock Mode Register
SSC_RCMR
Access Type:
31
Read/Write
30
29
28
27
26
25
24
19
18
17
16
10
9
8
PERIOD
23
22
21
20
STDDLY
15
–
7
14
–
13
–
12
STOP
11
6
5
CKI
4
3
CKO
CKG
START
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
Output
0x2
Receive Clock only during data transfers
Output
0x3-0x7
RK Pin
Input-only
Reserved
• CKI: Receive Clock Inversion
0: The data inputs (Data and Frame Sync signals) are sampled on Receive Clock falling edge. The Frame Sync signal output is shifted out on Receive Clock rising edge.
1: The data inputs (Data and Frame Sync signals) are sampled on Receive Clock rising edge. The Frame Sync signal output is shifted out on Receive Clock falling edge.
CKI affects only the Receive Clock and not the output clock signal.
551
6249B–ATARM–14-Dec-06
• CKG: Receive Clock Gating Selection
CKG
Receive Clock Gating
0x0
None, continuous clock
0x1
Receive Clock enabled only if RF Low
0x2
Receive Clock enabled only if RF High
0x3
Reserved
• 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 signal
0x3
Detection of a high level on RF signal
0x4
Detection of a falling edge on RF signal
0x5
Detection of a rising edge on RF signal
0x6
Detection of any level change on RF signal
0x7
Detection of any edge on RF signal
0x8
Compare 0
0x9-0xF
Reserved
• STOP: Receive Stop Selection
0: After completion of a data transfer when starting with a Compare 0, the receiver stops the data transfer and waits for a
new compare 0.
1: After starting a receive with a Compare 0, the receiver operates in a continuous mode until a Compare 1 is detected.
• 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.
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.
552
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
34.8.4
Name:
SSC Receive Frame Mode Register
SSC_RFMR
Access Type:
Read/Write
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
FSEDGE
23
–
22
21
FSOS
20
19
18
17
16
15
–
14
–
13
–
12
–
11
9
8
7
MSBF
6
–
5
LOOP
4
3
1
0
FSLEN
10
DATNB
2
DATLEN
• DATLEN: Data Length
0: Forbidden value (1-bit data length not supported).
Any other value: The bit stream contains DATLEN + 1 data bits. Moreover, it defines the transfer size performed by the
PDC2 assigned to the Receiver. If DATLEN is lower or equal to 7, data transfers are in bytes. If DATLEN is between 8 and
15 (included), half-words are transferred, and 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, which is equal to (DATNB + 1).
• FSLEN: Receive Frame Sync Length
This field defines the number of bits sampled and stored in the Receive Sync Data Register. When this mode is selected by
the START field in the Receive Clock Mode Register, it also determines the length of the sampled data to be compared to
the Compare 0 or Compare 1 register.
This field is used with FSLEN_EXT to determine the pulse length of the Receive Frame Sync signal.
Pulse length is equal to FSLEN + 1 Receive Clock periods.
553
6249B–ATARM–14-Dec-06
• 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
Input-only
Reserved
Undefined
• FSEDGE: Frame Sync Edge Detection
Determines which edge on Frame Sync will generate the interrupt RXSYN in the SSC Status Register.
FSEDGE
554
Frame Sync Edge Detection
0x0
Positive Edge Detection
0x1
Negative Edge Detection
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
34.8.5
Name:
SSC Transmit Clock Mode Register
SSC_TCMR
Access Type:
31
Read/Write
30
29
28
27
26
25
24
19
18
17
16
10
9
8
PERIOD
23
22
21
20
STTDLY
15
–
7
14
–
13
–
12
–
11
6
5
CKI
4
3
CKO
CKG
START
2
1
0
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
Output
0x2
Transmit Clock only during data transfers
Output
0x3-0x7
TK pin
Input-only
Reserved
• CKI: Transmit Clock Inversion
0: The data outputs (Data and Frame Sync signals) are shifted out on Transmit Clock falling edge. The Frame sync signal
input is sampled on Transmit clock rising edge.
1: The data outputs (Data and Frame Sync signals) are shifted out on Transmit Clock rising edge. The Frame sync signal
input is sampled on Transmit clock falling edge.
CKI affects only the Transmit Clock and not the output clock signal.
555
6249B–ATARM–14-Dec-06
• CKG: Transmit Clock Gating Selection
CKG
Transmit Clock Gating
0x0
None, continuous clock
0x1
Transmit Clock enabled only if TF Low
0x2
Transmit Clock enabled only if TF High
0x3
Reserved
• 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
• 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.
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.
556
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
34.8.6
Name:
SSC Transmit Frame Mode Register
SSC_TFMR
Access Type:
Read/Write
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
FSEDGE
23
FSDEN
22
21
FSOS
20
19
18
17
16
15
–
14
–
13
–
12
–
11
9
8
7
MSBF
6
–
5
DATDEF
4
3
1
0
FSLEN
10
DATNB
2
DATLEN
• DATLEN: Data Length
0: Forbidden value (1-bit data length not supported).
Any other value: The bit stream contains DATLEN + 1 data bits. Moreover, it defines the transfer size performed by the
PDC2 assigned to the Transmit. If DATLEN is lower or equal to 7, data transfers are bytes, if DATLEN is between 8 and 15
(included), half-words are transferred, and 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, which is equal to (DATNB +1).
• 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.
This field is used with FSLEN_EXT to determine the pulse length of the Transmit Frame Sync signal.
Pulse length is equal to FSLEN + 1 Transmit Clock periods.
557
6249B–ATARM–14-Dec-06
• 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
• 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 will generate the interrupt TXSYN (Status Register).
FSEDGE
558
Frame Sync Edge Detection
0x0
Positive Edge Detection
0x1
Negative Edge Detection
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
34.8.7
Name:
SSC Receive Holding Register
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
RDAT
7
6
5
4
RDAT
• RDAT: Receive Data
Right aligned regardless of the number of data bits defined by DATLEN in SSC_RFMR.
34.8.8
Name:
SSC Transmit Holding Register
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.
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6249B–ATARM–14-Dec-06
34.8.9
Name:
SSC Receive Synchronization Holding Register
SSC_RSHR
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
RSDAT
7
6
5
4
RSDAT
• RSDAT: Receive Synchronization Data
34.8.10
Name:
SSC Transmit Synchronization Holding Register
SSC_TSHR
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
TSDAT
7
6
5
4
TSDAT
• TSDAT: Transmit Synchronization Data
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34.8.11
Name:
SSC Receive Compare 0 Register
SSC_RC0R
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
CP0
7
6
5
4
CP0
• CP0: Receive Compare Data 0
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6249B–ATARM–14-Dec-06
34.8.12
Name:
SSC Receive Compare 1 Register
SSC_RC1R
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
CP1
7
6
5
4
CP1
• CP1: Receive Compare Data 1
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34.8.13
Name:
SSC Status Register
SSC_SR
Access Type:
Read-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
RXEN
16
TXEN
15
–
14
–
13
–
12
–
11
RXSYN
10
TXSYN
9
CP1
8
CP0
7
RXBUFF
6
ENDRX
5
OVRUN
4
RXRDY
3
TXBUFE
2
ENDTX
1
TXEMPTY
0
TXRDY
• TXRDY: Transmit Ready
0: Data has been loaded in SSC_THR and is waiting to be loaded in the Transmit Shift Register (TSR).
1: SSC_THR is empty.
• TXEMPTY: Transmit Empty
0: Data remains in SSC_THR or is currently transmitted from TSR.
1: Last data written in SSC_THR has been loaded in TSR and last data loaded in TSR has been transmitted.
• 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.
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6249B–ATARM–14-Dec-06
• CP0: Compare 0
0: A compare 0 has not occurred since the last read of the Status Register.
1: A compare 0 has occurred since the last read of the Status Register.
• CP1: Compare 1
0: A compare 1 has not occurred since the last read of the Status Register.
1: A compare 1 has occurred since the last read of the Status Register.
• TXSYN: Transmit Sync
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: An Rx Sync has not occurred since the last read of the Status Register.
1: An Rx Sync has occurred since the last read of the Status Register.
• TXEN: Transmit Enable
0: Transmit is disabled.
1: Transmit is enabled.
• RXEN: Receive Enable
0: Receive is disabled.
1: Receive is enabled.
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34.8.14
Name:
SSC Interrupt Enable Register
SSC_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
RXSYN
10
TXSYN
9
CP1
8
CP0
7
RXBUFF
6
ENDRX
5
OVRUN
4
RXRDY
3
TXBUFE
2
ENDTX
1
TXEMPTY
0
TXRDY
• TXRDY: Transmit Ready Interrupt Enable
0: No effect.
1: Enables the Transmit Ready Interrupt.
• TXEMPTY: Transmit Empty Interrupt Enable
0: No effect.
1: Enables the Transmit Empty Interrupt.
• ENDTX: End of Transmission Interrupt Enable
0: No effect.
1: Enables the End of Transmission Interrupt.
• TXBUFE: Transmit Buffer Empty Interrupt Enable
0: No effect.
1: Enables the Transmit Buffer Empty Interrupt
• RXRDY: Receive Ready Interrupt Enable
0: No effect.
1: Enables the Receive Ready Interrupt.
• OVRUN: Receive Overrun Interrupt Enable
0: No effect.
1: Enables the Receive Overrun Interrupt.
• ENDRX: End of Reception Interrupt Enable
0: No effect.
1: Enables the End of Reception Interrupt.
• RXBUFF: Receive Buffer Full Interrupt Enable
0: No effect.
1: Enables the Receive Buffer Full Interrupt.
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• CP0: Compare 0 Interrupt Enable
0: No effect.
1: Enables the Compare 0 Interrupt.
• CP1: Compare 1 Interrupt Enable
0: No effect.
1: Enables the Compare 1 Interrupt.
• TXSYN: Tx Sync Interrupt Enable
0: No effect.
1: Enables the Tx Sync Interrupt.
• RXSYN: Rx Sync Interrupt Enable
0: No effect.
1: Enables the Rx Sync Interrupt.
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34.8.15
Name:
SSC Interrupt Disable Register
SSC_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
RXSYN
10
TXSYN
9
CP1
8
CP0
7
RXBUFF
6
ENDRX
5
OVRUN
4
RXRDY
3
TXBUFE
2
ENDTX
1
TXEMPTY
0
TXRDY
• TXRDY: Transmit Ready Interrupt Disable
0: No effect.
1: Disables the Transmit Ready Interrupt.
• TXEMPTY: Transmit Empty Interrupt Disable
0: No effect.
1: Disables the Transmit Empty Interrupt.
• ENDTX: End of Transmission Interrupt Disable
0: No effect.
1: Disables the End of Transmission Interrupt.
• TXBUFE: Transmit Buffer Empty Interrupt Disable
0: No effect.
1: Disables the Transmit Buffer Empty Interrupt.
• RXRDY: Receive Ready Interrupt Disable
0: No effect.
1: Disables the Receive Ready Interrupt.
• OVRUN: Receive Overrun Interrupt Disable
0: No effect.
1: Disables the Receive Overrun Interrupt.
• ENDRX: End of Reception Interrupt Disable
0: No effect.
1: Disables the End of Reception Interrupt.
• RXBUFF: Receive Buffer Full Interrupt Disable
0: No effect.
1: Disables the Receive Buffer Full Interrupt.
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• CP0: Compare 0 Interrupt Disable
0: No effect.
1: Disables the Compare 0 Interrupt.
• CP1: Compare 1 Interrupt Disable
0: No effect.
1: Disables the Compare 1 Interrupt.
• TXSYN: Tx Sync Interrupt Enable
0: No effect.
1: Disables the Tx Sync Interrupt.
• RXSYN: Rx Sync Interrupt Enable
0: No effect.
1: Disables the Rx Sync Interrupt.
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34.8.16
Name:
SSC Interrupt Mask Register
SSC_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
RXSYN
10
TXSYN
9
CP1
8
CP0
7
RXBUF
6
ENDRX
5
OVRUN
4
RXRDY
3
TXBUFE
2
ENDTX
1
TXEMPTY
0
TXRDY
• TXRDY: Transmit Ready Interrupt Mask
0: The Transmit Ready Interrupt is disabled.
1: The Transmit Ready Interrupt is enabled.
• TXEMPTY: Transmit Empty Interrupt Mask
0: The Transmit Empty Interrupt is disabled.
1: The Transmit Empty Interrupt is enabled.
• ENDTX: End of Transmission Interrupt Mask
0: The End of Transmission Interrupt is disabled.
1: The End of Transmission Interrupt is enabled.
• TXBUFE: Transmit Buffer Empty Interrupt Mask
0: The Transmit Buffer Empty Interrupt is disabled.
1: The Transmit Buffer Empty Interrupt is enabled.
• RXRDY: Receive Ready Interrupt Mask
0: The Receive Ready Interrupt is disabled.
1: The Receive Ready Interrupt is enabled.
• OVRUN: Receive Overrun Interrupt Mask
0: The Receive Overrun Interrupt is disabled.
1: The Receive Overrun Interrupt is enabled.
• ENDRX: End of Reception Interrupt Mask
0: The End of Reception Interrupt is disabled.
1: The End of Reception Interrupt is enabled.
• RXBUFF: Receive Buffer Full Interrupt Mask
0: The Receive Buffer Full Interrupt is disabled.
1: The Receive Buffer Full Interrupt is enabled.
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• CP0: Compare 0 Interrupt Mask
0: The Compare 0 Interrupt is disabled.
1: The Compare 0 Interrupt is enabled.
• CP1: Compare 1 Interrupt Mask
0: The Compare 1 Interrupt is disabled.
1: The Compare 1 Interrupt is enabled.
• TXSYN: Tx Sync Interrupt Mask
0: The Tx Sync Interrupt is disabled.
1: The Tx Sync Interrupt is enabled.
• RXSYN: Rx Sync Interrupt Mask
0: The Rx Sync Interrupt is disabled.
1: The Rx Sync Interrupt is enabled.
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35. AC’97 Controller (AC’97C)
35.1
Description
The AC‘97 Controller is the hardware implementation of the AC’97 digital controller (DC’97)
compliant with AC’97 Component Specification 2.2. The AC’97 Controller communicates with
an audio codec (AC’97) or a modem codec (MC’97) via the AC-link digital serial interface. All
digital audio, modem and handset data streams, as well as control (command/status) informations are transferred in accordance to the AC-link protocol.
The AC’97 Controller features a Peripheral DMA Controller (PDC) for audio streaming transfers. It also supports variable sampling rate and four Pulse Code Modulation (PCM) sample
resolutions of 10, 16, 18 and 20 bits.
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35.2
Block Diagram
Figure 35-1. Functional Block Diagram
MCK Clock Domain
Slot Number
SYNC
AC97 Slot Controller
Slot Number
16/20 bits
Slot #0
Transmit Shift Register
M
AC97 Tag Controller
Receive Shift Register
Slot #0,1
U
AC97 CODEC Channel
AC97C_COTHR
AC97C_CORHR
X
Slot #1,2
Slot #2
SDATA_OUT
Transmit Shift Register
Receive Shift Register
SDATA_IN
AC97 Channel A
Transmit Shift Register
AC97C_CATHR
AC97C_CARHR
Slot #3...12
Receive Shift Register
D
E
BITCLK
M
AC97 Channel B
AC97C Interrupt
Transmit Shift Register
AC97C_CBTHR
U
Slot #3...12
AC97C_CBRHR
Receive Shift Register
X
MCK
User Interface
Bit Clock Domain
APB Interface
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35.3
Pin Name List
Table 35-1.
I/O Lines Description
Pin Name
Pin Description
Type
AC97CK
12.288-MHz bit-rate clock
Input
AC97RX
Receiver Data (Referred as SDATA_IN in AC-link spec)
Input
AC97FS
48-KHz frame indicator and synchronizer
Output
AC97TX
Transmitter Data (Referred as SDATA_OUT in AC-link spec)
Output
The AC‘97 reset signal provided to the primary codec can be generated by a PIO.
35.4
Application Block Diagram
Figure 35-2. Application Block diagram
AC-link
AC 97 Controller
PIOx
AC'97 Primary Codec
AC97_RESET
AC97_SYNC
AC97FS
AC97_BITCLK
AC97CK
AC97TX
AC97_SDATA_OUT
AC97_SDATA_IN
AC97RX
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35.5
35.5.1
Product Dependencies
I/O Lines
The pins used for interfacing the compliant external devices may be multiplexed with PIO
lines.
Before using the AC‘97 Controller receiver, the PIO controller must be configured in order for
the AC97C receiver I/O lines to be in AC‘97 Controller peripheral mode.
Before using the AC‘97 Controller transmitter, the PIO controller must be configured in order
for the AC97C transmitter I/O lines to be in AC‘97 Controller peripheral mode.
35.5.2
Power Management
The AC‘97 Controller is not continuously clocked. Its interface may be clocked through the
Power Management Controller (PMC), therefore the programmer must first configure the PMC
to enable the AC’97 Controller clock.
The AC’97 Controller has two clock domains. The first one is supplied by PMC and is equal to
MCK. The second one is AC97CK which is sent by the AC97 Codec (Bit clock).
Signals that cross the two clock domains are re-synchronized. MCK clock frequency must be
higher than the AC97CK (Bit Clock) clock frequency.
35.5.3
Interrupt
The AC’97 Controller interface has an interrupt line connected to the Advanced Interrupt Controller (AIC). Handling interrupts requires programming the AIC before configuring the AC97C.
All AC’97 Controller interrupts can be enabled/disabled by writing to the AC’97 Controller
Interrupt Enable/Disable Registers. Each pending and unmasked AC’97 Controller interrupt
will assert the interrupt line. The AC’97 Controller interrupt service routine can get the interrupt
source in two steps:
• Reading and ANDing AC’97 Controller Interrupt Mask Register (AC97C_IMR) and AC’97
Controller Status Register (AC97C_SR).
• Reading AC’97 Controller Channel x Status Register (AC97C_CxSR).
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35.6
Functional Description
35.6.1
Protocol overview
AC-link protocol is a bidirectional, fixed clock rate, serial digital stream. AC-link handles multiple input and output Pulse Code Modulation PCM audio streams, as well as control register
accesses employing a Time Division Multiplexed (TDM) scheme that divides each audio frame
in 12 outgoing and 12 incoming 20-bit wide data slots.
Figure 35-3. Bidirectional AC-link Frame with Slot Assignment
Slot #
0
1
2
3
4
5
6
7
8
9
10
11
12
PCM
L SURR
PCM
R SURR
PCM
LFE
LINE 2
DAC
HSET
DAC
IO
CTRL
RSVED
RSVED
LINE 2
ADC
HSET
ADC
IO
STATUS
AC97FS
AC97TX
(Controller Output)
TAG
CMD
ADDR
CMD
DATA
PCM
L Front
PCM
R Front
LINE 1
DAC
PCM
Center
AC97RX
(Codec output)
TAG
STATUS
ADDR
STATUS
DATA
PCM
LEFT
PCM
RIGHT
LINE 1
DAC
PCM
MIC
Table 35-2.
RSVED
AC-link Output Slots Transmitted from the AC’97C Controller
Slot #
Pin Description
0
TAG
1
Command Address Port
2
Command Data Port
3,4
PCM playback Left/Right Channel
5
Modem Line 1 Output Channel
6, 7, 8
PCM Center/Left Surround/Right Surround
9
PCM LFE DAC
10
Modem Line 2 Output Channel
11
Modem Handset Output Channel
12
Modem GPIO Control Channel
Table 35-3.
AC-link Input Slots Transmitted from the AC’97C Controller
Slot #
Pin Description
0
TAG
1
Status Address Port
2
Status Data Port
3,4
PCM playback Left/Right Channel
5
Modem Line 1 ADC
6
Dedicated Microphone ADC
7, 8, 9
Vendor Reserved
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6249B–ATARM–14-Dec-06
Table 35-3.
AC-link Input Slots Transmitted from the AC’97C Controller
Slot #
Pin Description
10
Modem Line 2 ADC
11
Modem Handset Input ADC
12
Modem IO Status
35.6.1.1
Slot Description
Tag Slot
The tag slot, or slot 0, is a 16-bit wide slot that always goes at the beginning of an outgoing or
incoming frame. Within tag slot, the first bit is a global bit that flags the entire frame validity.
The next 12 bit positions sampled by the AC’97 Controller indicate which of the corresponding
12 time slots contain valid data. The slot’s last two bits (combined) called Codec ID, are used
to distinguish primary and secondary codec.
The 16-bit wide tag slot of the output frame is automatically generated by the AC‘97 Controller
according to the transmit request of each channel and to the SLOTREQ from the previous
input frame, sent by the AC‘97 Codec, in Variable Sample Rate mode.
Codec Slot 1
The command/status slot is a 20-bit wide slot used to control features, and monitors status for
AC‘97 Codec functions.
The control interface architecture supports up to sixty-four 16-bit wide read/write registers.
Only the even registers are currently defined and addressed.
Slot 1’s bitmap is the following:
• Bit 19 is for read/write command, 1= read, 0 = write.
• Bits [18:12] are for control register index.
• Bits [11:0] are reserved.
Codec Slot 2
Slot 2 is a 20-bit wide slot used to carry 16-bit wide AC97 Codec control register data. If the
current command port operation is a read, the entire slot time is stuffed with zeros. Its bitmap
is the following:
• Bits [19:4] are the control register data
• Bits [3:0] are reserved and stuffed with zeros.
Data Slots [3:12]
Slots [3:12] are 20-bit wide data slots, they usually carry audio PCM or/and modem I/O data.
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35.6.2
AC‘97 Controller Channel Organization
The AC’97 Controller features a Codec channel and 2 logical channels; Channel A and Channel B.
The Codec channel controls AC‘97 Codec registers, it enables write and read configuration
values in order to bring the AC97 Codec to an operating state. The Codec channel always
runs slot 1 and slot 2 exclusively, in both input and output directions.
Channel A and Channel B transfer data to/from AC97 codec. All audio samples and modem
data must transit by these two channels. However, Channel A is connected to PDC channels
thus making it suitable for audio streaming applications.
Each slot of the input or the output frame that belongs to this range [3 to 12] can be operated
by either Channel A or Channel B. The slot to channel assignment is configured by two
registers:
• AC’97 Controller Input Channel Assignment Register (AC97C_ICA)
• AC’97 Controller Output Channel Assignment Register (AC97C_OCA)
The AC’97 Controller Input Channel Assignment Register (AC97C_ICA) configures the input
slot to channel assignment. The AC’97 Controller Output Channel Assignment Register
(AC97C_OCA) configures the output slot to channel assignment.
A slot can be left unassigned to a channel by the AC’97 Controller. Slots 0, 1,and 2 cannot be
assigned to Channel A or to Channel B through the AC97C_OCA and AC97C_ICA Registers.
The width of sample data, that transit via Channel A and Channel B varies and can take one of
these values; 10, 16, 18 or 20 bits.
Figure 35-4. Logical Channel Assignment
Slot #
0
1
2
3
4
5
6
7
PCM
L Front
PCM
R Front
LINE 1
DAC
PCM
Center
PCM
L SURR
LINE 1
DAC
PCM
MIC
RSVED
8
9
10
11
12
PCM
R SURR
PCM
LFE
LINE 2
DAC
HSET
DAC
IO
CTRL
RSVED
RSVED
LINE 2
ADC
HSET
ADC
IO
STATUS
AC97FS
AC97TX
(Controller Output)
TAG
CMD
ADDR
CMD
DATA
Codec Channel
Channel A
AC97C_OCA = 0x0000_0209
AC97RX
(Codec output)
TAG
STATUS
ADDR
STATUS
DATA
Codec Channel
PCM
LEFT
PCM
RIGHT
Channel A
AC97C_ICA = 0x0000_0009
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35.6.2.1
AC97 Controller Setup
The following operations must be performed in order to bring the AC’97 Controller into an
operating state:
1. Enable the AC97 Controller clock in the PMC controller.
2. Turn on AC97 function by enabling the ENA bit in AC97 Controller Mode Register
(AC97C_MR).
3. Configure the input channel assignment by controlling the AC’97 Controller Input
Assignment Register (AC97C_ICA).
4. Configure the output channel assignment by controlling the AC’97 Controller Input
Assignment Register (AC97C_OCA).
5. Configure sample width for Channel A and Channel B by writing the SIZE bit field in
AC97C Channel A Mode Register (AC97C_CAMR) and AC97C Channel B Mode
Register (AC97C_CBMR). The application can write 10, 16, 18,or 20-bit wide PCM
samples through the AC’97 interface and they will be transferred into 20-bit wide
slots.
6. Configure data Endianness for Channel A and Channel B by writing CEM bit field in
AC97C_CAMR and AC97C_CBMR registers. Data on the AC-link are shifted MSB
first. The application can write little- or big-endian data to the AC’97 Controller
interface.
7. Configure the PIO controller to drive the RESET signal of the external Codec. The
RESET signal must fulfill external AC97 Codec timing requirements.
8. Enable Channel A and/or Channel B by writing CEN bit field in AC97C_CAMR and
AC97C_CBMR registers.
35.6.2.2
Transmit Operation
The application must perform the following steps in order to send data via a channel to the
AC97 Codec:
• Check if previous data has been sent by polling TXRDY flag in the AC97C Channel x
Status Register (AC97_CxSR). x being one of the 2 channels.
• Write data to the AC’97 Controller Channel x Transmit Holding Register (AC97C_CxTHR).
Once data has been transferred to the Channel x Shift Register, the TXRDY flag is automatically set by the AC’97 Controller which allows the application to start a new write action. The
application can also wait for an interrupt notice associated with TXRDY in order to send data.
The interrupt remains active until TXRDY flag is cleared..
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Figure 35-5. Audio Transfer (PCM L Front, PCM R Front) on Channel x
Slot #
0
1
2
CMD
ADDR
CMD
DATA
3
4
5
6
7
8
9
10
11
12
AC97FS
AC97TX
(Controller Output)
TAG
PCM
L Front
PCM
R Front
LINE 1
DAC
PCM
Center
PCM
L SURR
PCM
R SURR
PCM
LFE
LINE 2
DAC
HSET
DAC
IO
CTRL
TXRDYCx
(AC97C_SR)
TXEMPTY
(AC97C_SR)
Write access to
AC97C_THRx
PCM L Front
transfered to the shift register
PCM R Front
transfered to the shift register
The TXEMPTY flag in the AC’97 Controller Channel x Status Register (AC97C_CxSR) is set
when all requested transmissions for a channel have been shifted on the AC-link. The application can either poll TXEMPTY flag in AC97C_CxSR or wait for an interrupt notice associated
with the same flag.
In most cases, the AC’97 Controller is embedded in chips that target audio player devices. In
such cases, the AC‘97 Controller is exposed to heavy audio transfers. Using the polling technique increases processor overhead and may fail to keep the required pace under an
operating system. In order to avoid these polling drawbacks, the application can perform audio
streams by using PDC connected to channel A, which reduces processor overhead and
increases performance especially under an operating system.
The PDC transmit counter values must be equal to the number of PCM samples to be transmitted, each sample goes in one slot.
35.6.2.3
AC‘97 Output Frame
The AC’97 Controller outputs a thirteen-slot frame on the AC-Link. The first slot (tag slot or slot
0) flags the validity of the entire frame and the validity of each slot; whether a slot carries valid
data or not. Slots 1 and 2 are used if the application performs control and status monitoring
actions on AC97 Codec control/status registers. Slots [3:12] are used according to the content
of the AC’97 Controller Output Channel Assignment Register (AC97C_OCA). If the application
performs many transmit requests on a channel, some of the slots associated to this channel or
all of them will carry valid data.
35.6.2.4
Receive Operation
The AC’97 Controller can also receive data from AC‘97 Codec. Data is received in the channel’s shift register and then transferred to the AC’97 Controller Channel x Read Holding
Register. To read the newly received data, the application must perform the following steps:
• Poll RXRDY flag in AC’97 Controller Channel x Status Register (AC97C_CxSR). x being
one of the 2 channels.
• Read data from AC’97 Controller Channel x Read Holding Register.
581
6249B–ATARM–14-Dec-06
The application can also wait for an interrupt notice in order to read data from
AC97C_CxRHR. The interrupt remains active until RXRDY is cleared by reading
AC97C_CxSR.
The RXRDY flag in AC97C_CxSR is set automatically when data is received in the Channel x
shift register. Data is then shifted to AC97C_CxRHR.
Figure 35-6. Audio Transfer (PCM L Front, PCM R Front) on Channel x
Slot #
0
1
2
TAG
STATUS
ADDR
STATUS
DATA
3
4
5
6
7
8
9
RSVED
RSVED
10
11
12
AC97FS
AC97RX
(Codec output)
PCM
LEFT
PCM
RIGHT
LINE 1
DAC
PCM
MIC
RSVED
LINE 2
ADC
HSET
ADC
IO
STATUS
RXRDYCx
(AC97C_SR)
Read access to
AC97C_RHRx
If the previously received data has not been read by the application, the new data overwrites
the data already waiting in AC97C_CxRHR, therefore the OVRUN flag in AC97C_CxSR is
raised. The application can either poll the OVRUN flag in AC97C_CxSR or wait for an interrupt
notice. The interrupt remains active until the OVRUN flag in AC97C_CxSR is set.
The AC’97 Controller can also be used in sound recording devices in association with an
AC97 Codec. The AC‘97 Controller may also be exposed to heavy PCM transfers. The application can usethe PDC connected to channel A in order to reduce processor overhead and
increase performance especially under an operating system.
The PDC receive counter values must be equal to the number of PCM samples to be received,
each sample goes in one slot.
35.6.2.5
AC‘97 Input Frame
The AC’97 Controller receives a thirteen slot frame on the AC-Link sent by the AC97 Codec.
The first slot (tag slot or slot 0) flags the validity of the entire frame and the validity of each slot;
whether a slot carries valid data or not. Slots 1 and 2 are used if the application requires status
informations from AC97 Codec. Slots [3:12] are used according to AC’97 Controller Output
Channel Assignment Register (AC97C_ICA) content. The AC’97 Controller will not receive
any data from any slot if AC97C_ICA is not assigned to a channel in input.
35.6.2.6
Configuring and Using Interrupts
Instead of polling flags in AC’97 Controller Global Status Register (AC97C_SR) and in AC’97
Controller Channel x Status Register (AC97C_CxSR), the application can wait for an interrupt
notice. The following steps show how to configure and use interrupts correctly:
• Set the interruptible flag in AC’97 Controller Channel x Mode Register (AC97C_CxMR).
• Set the interruptible event and channel event in AC’97 Controller Interrupt Enable Register
(AC97C_IER).
The interrupt handler must read both AC’97 Controller Global Status Register (AC97C_SR)
and AC’97 Controller Interrupt Mask Register (AC97C_IMR) and AND them to get the real
interrupt source. Furthermore, to get which event was activated, the interrupt handler has to
582
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
read AC’97 Controller Channel x Status Register (AC97C_CxSR), x being the channel whose
event triggers the interrupt.
The application can disable event interrupts by writing in AC’97 Controller Interrupt Disable
Register (AC97C_IDR). The AC‘97 Controller Interrupt Mask Register (AC97C_IMR) shows
which event can trigger an interrupt and which one cannot.
35.6.2.7
Endianness
Endianness can be managed automatically for each channel, except for the Codec channel,
by writing to Channel Endianness Mode (CEM) in AC97C_CxMR. This enables transferring
data on AC-link in Big Endian format without any additional operation.
To Transmit a Word Stored in Big Endian Format on AC-link
Word to be written in AC’97 Controller Channel x Transmit Holding Register (AC97C_CxTHR)
(as it is stored in memory or microprocessor register).
31
24
23
16
Byte0[7:0]
15
Byte1[7:0]
8
7
Byte2[7:0]
0
Byte3[7:0]
Word stored in Channel x Transmit Holding Register (AC97C_CxTHR) (data to transmit).
31
24
23
–
20
19
16
Byte2[3:0]
–
15
8
7
Byte1[7:0]
0
Byte0[7:0]
Data transmitted on appropriate slot: data[19:0] = {Byte2[3:0], Byte1[7:0], Byte0[7:0]}.
To Transmit A Halfword Stored in Big Indian Format on AC-link
Halfword to be written in AC’97 Controller Channel x Transmit Holding Register
(AC97C_CxTHR).
31
24
23
–
16
15
–
8
7
Byte0[7:0]
0
Byte1[7:0]
Halfword stored in AC’97 Controller Channel x Transmit Holding Register (AC97C_CxTHR)
(data to transmit).
31
24
23
–
16
15
–
8
7
Byte1[7:0]
0
Byte0[7:0]
Data emitted on related slot: data[19:0] = {0x0, Byte1[7:0], Byte0[7:0]}.
To Transmit a10-bit Sample Stored in Big Endian Format on AC-link
Halfword to be written in AC’97 Controller Channel x Transmit Holding Register
(AC97C_CxTHR).
31
24
23
–
16
15
–
8
7
Byte0[7:0]
0
{0x00, Byte1[1:0]}
Halfword stored in AC’97 Controller Channel x Transmit Holding Register (AC97C_CxTHR)
(data to transmit).
31
24
–
23
16
–
15
10
–
9
8
Byte1
[1:0]
7
0
Byte0[7:0]
583
6249B–ATARM–14-Dec-06
Data emitted on related slot: data[19:0] = {0x000, Byte1[1:0], Byte0[7:0]}.
To Receive Word transfers
Data received on appropriate slot: data[19:0] = {Byte2[3:0], Byte1[7:0], Byte0[7:0]}.
Word stored in AC’97 Controller Channel x Receive Holding Register (AC97C_CxRHR)
(Received Data).
31
24
23
–
20
19
16
Byte2[3:0]
–
15
8
7
Byte1[7:0]
0
Byte0[7:0]
Data is read from AC’97 Controller Channel x Receive Holding Register (AC97C_CxRHR)
when Channel x data size is greater than 16 bits and when big-endian mode is enabled (data
written to memory).
31
24
23
Byte0[7:0]
16
15
Byte1[7:0]
8
7
0
{0x0, Byte2[3:0]}
0x00
To Receive Halfword Transfers
Data received on appropriate slot: data[19:0] = {0x0, Byte1[7:0], Byte0[7:0]}.
Halfword stored in AC’97 Controller Channel x Receive Holding Register (AC97C_CxRHR)
(Received Data).
31
24
23
–
16
15
–
8
7
Byte1[7:0]
0
Byte0[7:0]
Data is read from AC’97 Controller Channel x Receive Holding Register (AC97C_CxRHR)
when data size is equal to 16 bits and when big-endian mode is enabled.
31
24
23
–
16
15
–
8
7
Byte0[7:0]
0
Byte1[7:0]
To Receive 10-bit Samples
Data received on appropriate slot: data[19:0] = {0x000, Byte1[1:0], Byte0[7:0]}.Halfword stored
in AC’97 Controller Channel x Receive Holding Register (AC97C_CxRHR) (Received Data)
31
24
23
–
16
–
15
10
–
9
8
Byte1
[1:0]
7
0
Byte0[7:0]
Data read from AC’97 Controller Channel x Receive Holding Register (AC97C_CxRHR) when
data size is equal to 10 bits and when big-endian mode is enabled.
31
24
–
35.6.3
584
23
16
–
15
Byte0[7:0]
8
7
3
0x00
1
0
Byte1
[1:0]
Variable Sample Rate
The problem of variable sample rate can be summarized by a simple example. When passing
a 44.1 kHz stream across the AC-link, for every 480 audio output frames that are sent across,
441 of them must contain valid sample data. The new AC’97 standard approach calls for the
addition of “on-demand” slot request flags. The AC‘97 Codec examines its sample rate control
register, the state of its FIFOs, and the incoming SDATA_OUT tag bits (slot 0) of each output
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
frame and then determines which SLOTREQ bits to set active (low). These bits are passed
from the AC97 Codec to the AC’97 Controller in slot 1/SLOTREQ in every audio input frame.
Each time the AC‘97 controller sees one or more of the newly defined slot request flags set
active (low) in a given audio input frame, it must pass along the next PCM sample for the corresponding slot(s) in the AC-link output frame that immediately follows.
The variable Sample Rate mode is enabled by performing the following steps:
• Setting the VRA bit in the AC’97 Controller Mode Register (AC97C_MR).
• Enable Variable Rate mode in the AC‘97 Codec by performing a transfer on the Codec
channel.
Slot 1 of the input frame is automatically interpreted as SLOTREQ signaling bits. The AC’97
Controller will automatically fill the active slots according to both SLOTREQ and AC97C_OCA
register in the next transmitted frame.
35.6.4
35.6.4.1
Power Management
Powering Down the AC-Link
The AC97 Codecs can be placed in low power mode. The application can bring AC97 Codec
to a power down state by performing sequential writes to AC97 Codec powerdown register .
Both the bit clock (clock delivered by AC97 Codec, AC97CK) and the input line (AC97RX) are
held at a logic low voltage level. This puts AC97 Codec in power down state while all its registers are still holding current values. Without the bit clock, the AC-link is completely in a power
down state.
The AC’97 Controller should not attempt to play or capture audio data until it has awakened
AC97 Codec.
To set the AC’97 Codec in low power mode, the PR4 bit in the AC’97 Codec powerdown register (Codec address 0x26) must be set to 1. Then the primary Codec drives both AC97CK
and AC97RX to a low logic voltage level.
The following operations must be done to put AC97 Codec in low power mode:
• Disable Channel A clearing CEN in the AC97C_CAMR register.
• Disable Channel B clearing CEN field in the AC97C_CBMR register.
• Write 0x2680 value in the AC97C_COTHR register.
• Poll the TXEMPTY flag in AC97C_CxSR registers for the 2 channels.
At this point AC97 Codec is in low power mode.
35.6.4.2
Waking up the AC-link
There are two methods to bring the AC-link out of low power mode. Regardless of the method,
it is always the AC97 Controller that performs the wake-up.
Wake-up Tiggered by the AC’97 Controller
The AC’97 Controller can wake up the AC97 Codec by issuing either a cold or a warm reset.
The AC’97 Controller can also wake up the AC97 Codec by asserting AC97FS signal, however this action should not be performed for a minimum period of four audio frames following
the frame in which the powerdown was issued.
Wake-up Triggered by the AC97 Codec
585
6249B–ATARM–14-Dec-06
This feature is implemented in AC97 modem codecs that need to report events such as CallerID and wake-up on ring.
The AC97 Codec can drive AC97RX signal from low to high level and holding it high until the
controller issues either a cold or a worm reset. The AC97RX rising edge is asynchronously
(regarding AC97FS) detected by the AC’97 Controller. If WKUP bit is enabled in AC97C_IMR
register, an interrupt is triggered that wakes up the AC‘97 Controller which should then immediately issue a cold or a warm reset.
If the processor needs to be awakened by an external event, the AC97RX signal must be
externally connected to the WAKEUP entry of the system controller.
Figure 35-7. AC’97 Power-Down/Up Sequence
Wake Event
Power Down Frame
Sleep State
Warm Reset
New Audio Frame
AC97CK
AC97FS
35.6.4.3
AC97TX
TAG
Write to
0x26
Data
PR4
TAG
Slot1
Slot2
AC97RX
TAG
Write to
0x26
Data
PR4
TAG
Slot1
Slot2
AC97 Codec Reset
There are three ways to reset an AC97 Codec.
Cold AC’97 Reset
A cold reset is generated by asserting the RESET signal low for the minimum specified time
(depending on the AC97 Codec) and then by de-asserting RESET high. AC97CK and
AC97FS is reactivated and all AC97 Codec registers are set to their default power-on values.
Transfers on AC-link can resume.
The RESET signal will be controlled via a PIO line. This is how an application should perform
a cold reset:
• Clear and set ENA flag in the AC97C_MR register to reset the AC’97 Controller
• Clear PIO line output controlling the AC’97 RESET signal
• Wait for the minimum specified time
• Set PIO line output controlling the AC’97 RESET signal
AC97CK, the clock provided by AC97 Codec, is detected by the controller.
Warm AC’97 Reset
A warm reset reactivates the AC-link without altering AC97 Codec registers. A warm reset is
signaled by driving AC97FX signal high for a minimum of 1us in the absence of AC97CK. In
the absence of AC97CK, AC97FX is treated as an asynchronous (regarding AC97FX) input
used to signal a warm reset to AC97 Codec.
This is the right way to perform a warm reset:
• Set WRST in the AC97C_MR register.
586
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
• Wait for at least 1 us
• Clear WRST in the AC97C_MR register.
The application can check that operations have resumed by checking SOF flag in the
AC97C_SR register or wait for an interrupt notice if SOF is enabled in AC97C_IMR.
587
6249B–ATARM–14-Dec-06
35.7
AC’97 Controller (AC97C) User Interface
Table 35-4.
Register Mapping
Offset
0x0-0x4
Reserved
Register Name
Access
Reset
–
–
–
AC97C_MR
Read/Write
0x0
–
–
–
0x8
Mode Register
0xC
Reserved
0x10
Input Channel Assignment Register
AC97C_ICA
Read/Write
0x0
0x14
Output Channel Assignment Register
AC97C_OCA
Read/Write
0x0
–
–
–
0x18-0x1C
Reserved
0x20
Channel A Receive Holding Register
AC97C_CARHR
Read
0x0
0x24
Channel A Transmit Holding Register
AC97C_CATHR
Write
–
0x28
Channel A Status Register
AC97C_CASR
Read
0x0
0x2C
Channel A Mode Register
AC97C_CAMR
Read/Write
0x0
0x30
Channel B Receive Holding Register
AC97C_CBRHR
Read
0x0
0x34
Channel B Transmit Holding Register
AC97C_CBTHR
Write
–
0x38
Channel B Status Register
AC97C_CBSR
Read
0x0
0x3C
Channel B Mode Register
AC97C_CBMR
Read/Write
0x0
0x40
Codec Receive Holding Register
AC97C_CORHR
Read
0x0
0x44
Codec Transmit Holding Register
AC’97C_COTHR
Write
–
0x48
Codec Status Register
AC’97C_COSR
Read
0x0
0x4C
Codec Mode Register
AC’97C_COMR
Read/Write
0x0
0x50
Status Register
AC97C_SR
Read
0x0
0x54
Interrupt Enable Register
AC97C_IER
Write
–
0x58
Interrupt Disable Register
AC97C_IDR
Write
–
0x5C
Interrupt Mask Register
AC97C_IMR
Read
0x0
–
–
–
AC97C_CARPR,
AC97C_CARCR,
AC97C_CATPR,
AC97C_CATCR,
AC97C_CARNPR,
AC97C_CARNCR,
AC97C_CATNPR,
AC97C_CATNCR,
AC97C_CAPTCR,
AC97C_CAPTSR
–
–
0x60-0xFB
0x100- 0x124
588
Register
Reserved
Reserved for Peripheral Data Controller (PDC),
registers related to Channel A transfers
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
35.7.1
AC’97 Controller Mode Register
Name:
AC97C_MR
Access Type:
Read-Write
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
–
28
–
20
–
12
–
4
–
27
–
19
–
11
–
3
–
26
–
18
–
10
–
2
VRA
25
–
17
–
9
–
1
WRST
24
–
16
–
8
–
0
ENA
25
CHID11
17
24
• VRA: Variable Rate (for Data Slots 3-12)
0: Variable Rate is inactive. (48 KHz only)
1: Variable Rate is active.
• WRST: Warm Reset
0: Warm Reset is inactive.
1: Warm Reset is active.
• ENA: AC’97 Controller Global Enable
0: No effect. AC’97 function as well as access to other AC’97 Controller registers are disabled.
1: Activates the AC’97 function.
35.7.2
AC’97 Controller Input Channel Assignment Register
Register Name:
AC97C_ICA
Access Type:
Read/Write
31
–
23
30
–
22
CHID10
14
15
CHID8
7
6
29
21
13
CHID7
5
CHID5
28
CHID12
20
12
4
CHID4
27
26
19
CHID9
11
18
3
16
CHID8
10
CHID6
2
9
1
CHID3
8
CHID5
0
• CHIDx: Channel ID for the input slot x
CHIDx
Selected Receive Channel
0x0
None. No data will be received during this Slot x
0x1
Channel A data will be received during this slot time.
0x2
Channel B data will be received during this slot time
589
6249B–ATARM–14-Dec-06
35.7.3
AC’97 Controller Output Channel Assignment Register
Register Name:
AC97C_OCA
Access Type:
Read/Write
31
–
23
30
–
22
CHID10
14
15
CHID8
7
6
29
21
13
CHID7
5
CHID5
28
CHID12
20
12
4
CHID4
27
26
19
CHID9
11
18
3
25
CHID11
17
24
16
CHID8
10
CHID6
2
9
1
CHID3
8
CHID5
0
• CHIDx: Channel ID for the output slot x
CHIDx
590
Selected Transmit Channel
0x0
None. No data will be transmitted during this Slot x
0x1
Channel A data will be transferred during this slot time.
0x2
Channel B data will be transferred during this slot time
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
35.7.4
AC’97 Controller Codec Channel Receive Holding Register
Register Name:
AC97C_CORHR
Access Type:
Read-only
31
–
23
–
15
30
–
22
–
14
29
–
21
–
13
28
–
20
–
12
27
–
19
–
11
26
–
18
–
10
25
–
17
–
9
24
–
16
–
8
3
2
1
0
27
–
19
CADDR
11
26
–
18
25
–
17
24
–
16
10
9
8
3
2
1
0
SDATA
7
6
5
4
SDATA
• SDATA: Status Data
Data sent by the CODEC in the third AC’97 input frame slot (Slot 2).
35.7.5
AC’97 Controller Codec Channel Transmit Holding Register
Register Name:
AC97C_COTHR
Access Type:
Write-only
31
–
23
READ
15
30
–
22
29
–
21
28
–
20
14
13
12
CDATA
7
6
5
4
CDATA
• READ: Read/Write command
0: Write operation to the CODEC register indexed by the CADDR address.
1: Read operation to the CODEC register indexed by the CADDR address.
This flag is sent during the second AC’97 frame slot
• CADDR: CODEC control register index
Data sent to the CODEC in the second AC’97 frame slot.
• CDATA: Command Data
Data sent to the CODEC in the third AC’97 frame slot (Slot 2).
591
6249B–ATARM–14-Dec-06
35.7.6
AC’97 Controller Channel A, Channel B Receive Holding Register
Register Name:
AC97C_CARHR, AC97C_CBRHR
Access Type:
Read-only
31
–
23
–
15
30
–
22
–
14
29
–
21
–
13
28
–
20
–
12
27
–
19
26
–
18
25
–
17
24
–
16
11
10
9
8
3
2
1
0
26
–
18
25
–
17
24
–
16
RDATA
RDATA
7
6
5
4
RDATA
• RDATA: Receive Data
Received Data on channel x.
35.7.7
AC’97 Controller Channel A, Channel B Transmit Holding Register
Register Name:
AC97C_CATHR, AC97C_CBTHR
Access Type:
Write-only
31
–
23
–
15
30
–
22
–
14
29
–
21
–
13
28
–
20
–
12
27
–
19
TDATA
11
10
9
8
3
2
1
0
TDATA
7
6
5
4
TDATA
• TDATA: Transmit Data
Data to be sent on channel x.
592
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
35.7.8
AC’97 Controller Channel A Status Register
Register Name:
AC97C_CASR
Access Type:
Read-only
31
–
23
–
15
RXBUFF
7
–
35.7.9
30
–
22
–
14
ENDRX
6
–
29
–
21
–
13
–
5
OVRUN
28
–
20
–
12
–
4
RXRDY
27
–
19
–
11
TXBUFE
3
–
26
–
18
–
10
ENDTX
2
UNRUN
25
–
17
–
9
–
1
TXEMPTY
24
–
16
–
8
–
0
TXRDY
27
–
19
–
11
–
3
–
26
–
18
–
10
–
2
UNRUN
25
–
17
–
9
–
1
TXEMPTY
24
–
16
–
8
–
0
TXRDY
27
–
19
–
11
–
3
–
26
–
18
–
10
–
2
UNRUN
25
–
17
–
9
–
1
TXEMPTY
24
–
16
–
8
–
0
TXRDY
AC’97 Controller Channel B Status Register
Register Name:
AC97C_CBSR
Access Type:
Read-only
31
–
23
–
15
–
7
–
35.7.10
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
OVRUN
28
–
20
–
12
–
4
RXRDY
AC’97 Controller Codec Channel Status Register
Register Name:
AC97C_COSR
Access Type:
Read-only
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
OVRUN
28
–
20
–
12
–
4
RXRDY
• TXRDY: Channel Transmit Ready
0: Data has been loaded in Channel Transmit Register and is waiting to be loaded in the Channel Transmit Shift Register.
1: Channel Transmit Register is empty.
• TXEMPTY: Channel Transmit Empty
0: Data remains in the Channel Transmit Register or is currently transmitted from the Channel Transmit Shift Register.
1: Data in the Channel Transmit Register have been loaded in the Channel Transmit Shift Register and sent to the codec.
• UNRUN: Transmit Underrun
Active only when Variable Rate Mode is enabled (VRA bit set in the AC97C_MR register). Automatically cleared by a processor read operation.
0: No data has been requested from the channel since the last read of the Status Register, or data has been available each
time the CODEC requested new data from the channel since the last read of the Status Register.
593
6249B–ATARM–14-Dec-06
1: Data has been emitted while no valid data to send has been previously loaded into the Channel Transmit Shift Register
since the last read of the Status Register.
• RXRDY: Channel Receive Ready
0: Channel Receive Holding Register is empty.
1: Data has been received and loaded in Channel Receive Holding Register.
• OVRUN: Receive Overrun
Automatically cleared by a processor read operation.
0: No data has been loaded in the Channel Receive Holding Register while previous data has not been read since the last
read of the Status Register.
1: Data has been loaded in the Channel Receive Holding Register while previous data has not yet been read since the last
read of the Status Register.
• ENDRX: End of Reception for Channel x
0: The register AC97C_CxRCR has not reached 0 since the last write in AC97C_CxRCR or AC97C_CxRNCR.
1: The register AC97C_CxRCR has reached 0 since the last write in AC97C_CxRCR or AC97C_CxRNCR.
• RXBUFF: Receive Buffer Full for Channel x
0: AC97C_CxRCR or AC97C_CxRNCR have a value other than 0.
1: Both AC97C_CxRCR and AC97C_CxRNCR have a value of 0.
• ENDTX: End of Transmission for Channel x
0: The register AC97C_CxTCR has not reached 0 since the last write in AC97C_CxTCR or AC97C_CxNCR.
1: The register AC97C_CxTCR has reached 0 since the last write in AC97C_CxTCR or AC97C_CxTNCR.
• TXBUFE: Transmit Buffer Empty for Channel x
0: AC97C_CxTCR or AC97C_CxTNCR have a value other than 0.
1: Both AC97C_CxTCR and AC97C_CxTNCR have a value of 0.
594
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
35.7.11
AC’97 Controller Channel A Mode Register
Register Name:
AC97C_CAMR
Access Type:
Read/Write
31
–
23
–
15
RXBUFF
7
–
35.7.12
30
–
22
PDCEN
14
ENDRX
6
–
29
–
21
CEN
13
–
5
OVRUN
28
–
20
–
12
–
4
RXRDY
27
–
19
–
11
TXBUFE
3
–
26
–
18
CEM
10
ENDTX
2
UNRUN
27
–
19
–
11
–
3
–
26
–
18
CEM
10
–
2
UNRUN
25
–
17
24
–
16
SIZE
9
–
1
TXEMPTY
8
–
0
TXRDY
25
–
17
24
–
16
AC’97 Controller Channel B Mode Register
Register Name:
AC97C_CBMR
Access Type:
Read/Write
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
CEN
13
–
5
OVRUN
28
–
20
–
12
–
4
RXRDY
SIZE
9
–
1
TXEMPTY
8
–
0
TXRDY
• CEM: Channel x Endian Mode
0: Transferring data through Channel x is straightforward (Little-endian).
1: Transferring data through Channel x from/to a memory is performed with from/to Big-endian format translation.
• SIZE: Channel x Data Size
SIZE Encoding
SIZE
Note:
Selected Channel
0x0
20 bits
0x1
18bits
0x2
16 bits
0x3
10 bits
Each time slot in the data phase is 20 bits long. For example, if a 16-bit sample stream is being played to an AC97 DAC, the first
16 bit positions are presented to the DAC MSB-justified. They are followed by the next four bit positions that the AC’97 Controller
fills with zeroes. This process ensures that the least significant bits do not introduce any DC biasing, regardless of the implemented DAC’s resolution (16-, 18-, or 20-bit).
• CEN: Channel x Enable
0: Data transfer is disabled on Channel x.
1: Data transfer is enabled on Channel x.
• PDCCEN: Peripheral Data Controller Channel Enable
0: Channel x is not transferred through a Peripheral Data Controller Channel. Related PDC flags are ignored or not
generated.
1: Channel x is transferred through a Peripheral Data Controller Channel. Related PDC flags are taken into account or
generated.
595
6249B–ATARM–14-Dec-06
35.7.13
AC’97 Controller Codec Channel Mode Register
Register Name:
AC97C_COMR
Access Type:
Read/Write
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
OVRUN
28
–
20
–
12
–
4
RXRDY
27
–
19
–
11
–
3
–
26
–
18
–
10
–
2
UNRUN
25
–
17
–
9
–
1
TXEMPTY
24
–
16
–
8
–
0
TXRDY
• TXRDY: Channel Transmit Ready Interrupt Enable
• TXEMPTY: Channel Transmit Empty Interrupt Enable
• UNRUN: Transmit Underrun Interrupt Enable
• RXRDY: Channel Receive Ready Interrupt Enable
• OVRUN: Receive Overrun Interrupt Enable
• ENDRX: End of Reception for channel x Interrupt Enable
• RXBUFF: Receive Buffer Full for channel x Interrupt Enable
• ENDTX: End of Transmission for channel x Interrupt Enable
• TXBUFE: Transmit Buffer Empty for channel x Interrupt Enable
0: Read: the corresponding interrupt is disabled. Write: disables the corresponding interrupt.
1: Read: the corresponding interrupt is enabled. Write: enables the corresponding interrupt.
596
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
35.7.14
AC’97 Controller Status Register
Register Name:
AC97C_SR
Access Type:
Read-only
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
28
–
20
–
12
–
4
CBEVT
27
–
19
–
11
–
3
CAEVT
26
–
18
–
10
–
2
COEVT
25
–
17
–
9
–
1
WKUP
24
–
16
–
8
–
0
SOF
WKUP and SOF flags in AC97C_SR register are automatically cleared by a processor read operation.
• SOF: Start Of Frame
0: No Start of Frame has been detected since the last read of the Status Register.
1: At least one Start of frame has been detected since the last read of the Status Register.
• WKUP: Wake Up detection
0: No Wake-up has been detected.
1: At least one rising edge on SDATA_IN has been asynchronously detected. That means AC’97 Codec has notified a
wake-up.
• COEVT: CODEC Channel Event
A Codec channel event occurs when AC97C_COSR AND AC97C_COMR is not 0. COEVT flag is automatically cleared
when the channel event condition is cleared.
0: No event on the CODEC channel has been detected since the last read of the Status Register.
1: At least one event on the CODEC channel is active.
• CAEVT: Channel A Event
A channel A event occurs when AC97C_CASR AND AC97C_CAMR is not 0. CAEVT flag is automatically cleared when the
channel event condition is cleared.
0: No event on the channel A has been detected since the last read of the Status Register.
1: At least one event on the channel A is active.
• CBEVT: Channel B Event
A channel B event occurs when AC97C_CBSR AND AC97C_CBMR is not 0. CBEVT flag is automatically cleared when the
channel event condition is cleared.
0: No event on the channel B has been detected since the last read of the Status Register.
1: At least one event on the channel B is active.
597
6249B–ATARM–14-Dec-06
35.7.15
AC’97 Controller Interrupt Enable Register
Register Name:
AC97C_IER
Access Type:
Write-only
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
–
28
–
20
–
12
–
4
CBEVT
27
–
19
–
11
–
3
CAEVT
26
–
18
–
10
–
2
COEVT
25
–
17
–
9
–
1
WKUP
24
–
16
–
8
–
0
SOF
27
–
19
–
11
–
3
CAEVT
26
–
18
–
10
–
2
COEVT
25
–
17
–
9
–
1
WKUP
24
–
16
–
8
–
0
SOF
• SOF: Start Of Frame
• WKUP: Wake Up
• COEVT: Codec Event
• CAEVT: Channel A Event
• CBEVT: Channel B Event
0: No effect.
1: Enables the corresponding interrupt.
35.7.16
AC’97 Controller Interrupt Disable Register
Register Name:
AC97C_IDR
Access Type:
Write-only
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
–
28
–
20
–
12
–
4
CBEVT
• SOF: Start Of Frame
• WKUP: Wake Up
• COEVT: Codec Event
• CAEVT: Channel A Event
• CBEVT: Channel B Event
0: No effect.
1: Disables the corresponding interrupt.
598
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
35.7.17
AC’97 Controller Interrupt Mask Register
Register Name:
AC97C_IMR
Access Type:
Read-only
31
–
23
–
15
–
7
–
30
–
22
–
14
–
6
–
29
–
21
–
13
–
5
–
28
–
20
–
12
–
4
CBEVT
27
–
19
–
11
–
3
CAEVT
26
–
18
–
10
–
2
COEVT
25
–
17
–
9
–
1
WKUP
24
–
16
–
8
–
0
SOF
• SOF: Start Of Frame
• WKUP: Wake Up
• COEVT: Codec Event
• CAEVT: Channel A Event
• CBEVT: Channel B Event
0: The corresponding interrupt is disabled.
1: The corresponding interrupt is enabled.
599
6249B–ATARM–14-Dec-06
600
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
36. Timer Counter (TC)
36.1
Description
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.
Table 36-1 gives the assignment of the device Timer Counter clock inputs common to Timer
Counter 0 to 2
Table 36-1.
Timer Counter Clock Assignment
Name
Definition
TIMER_CLOCK1
MCK/2
TIMER_CLOCK2
MCK/8
TIMER_CLOCK3
MCK/32
TIMER_CLOCK4
MCK/128
TIMER_CLOCK5
SLCK
601
6249B–ATARM–14-Dec-06
36.2
Block Diagram
Figure 36-1. Timer Counter Block Diagram
Parallel I/O
Controller
TIMER_CLOCK1
TCLK0
TIMER_CLOCK2
TIOA1
XC0
TIOA2
TIMER_CLOCK3
XC1
TCLK1
TIMER_CLOCK4
Timer/Counter
Channel 0
TIOA
TIOA0
TIOB0
TIOA0
TIOB
XC2
TCLK2
TIMER_CLOCK5
TIOB0
TC0XC0S
SYNC
TCLK0
TCLK1
TCLK2
INT0
TCLK0
XC0
TCLK1
XC1
TIOA0
Timer/Counter
Channel 1
TIOA
TIOA1
TIOB1
TIOA1
TIOB
XC2
TIOA2
TCLK2
TIOB1
SYNC
TC1XC1S
TCLK0
XC0
TCLK1
XC1
TCLK2
XC2
Timer/Counter
Channel 2
INT1
TIOA
TIOA2
TIOB2
TIOA2
TIOB
TIOB2
TIOA0
TIOA1
SYNC
TC2XC2S
INT2
Timer Counter
Advanced
Interrupt
Controller
Table 36-2.
Signal Name Description
Block/Channel
Signal Name
XC0, XC1, XC2
Channel Signal
External Clock Inputs
TIOA
Capture Mode: Timer Counter Input
Waveform Mode: Timer Counter Output
TIOB
Capture Mode: Timer Counter Input
Waveform Mode: Timer Counter Input/Output
INT
SYNC
602
Description
Interrupt Signal Output
Synchronization Input Signal
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
36.3
Pin Name List
Table 36-3.
36.4
36.4.1
TC 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
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.
36.4.2
Power Management
The TC is clocked through the Power Management Controller (PMC), thus the programmer must
first configure the PMC to enable the Timer Counter clock.
36.4.3
Interrupt
The TC has an interrupt line connected to the Advanced Interrupt Controller (AIC). Handling the
TC interrupt requires programming the AIC before configuring the TC.
603
6249B–ATARM–14-Dec-06
36.5
Functional Description
36.5.1
TC Description
The three channels of the Timer Counter are independent and identical in operation. The registers for channel programming are listed in Table 36-5 on page 617.
36.5.2
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.
36.5.3
Clock Selection
At block level, input clock signals of each channel can either be connected to the external inputs
TCLK0, TCLK1 or TCLK2, or be connected to the internal I/O signals TIOA0, TIOA1 or TIOA2
for chaining by programming the TC_BMR (Block Mode). See Figure 36-2 on page 605.
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
• External clock signals: XC0, XC1 or XC2
This selection is made by the TCCLKS bits in the TC Channel Mode Register.
The selected clock can be inverted with the CLKI bit in TC_CMR. 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). See Figure 36-3 on
page 605
Note:
604
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
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Figure 36-2. Clock Chaining Selection
TC0XC0S
Timer/Counter
Channel 0
TCLK0
TIOA1
XC0
TIOA2
TIOA0
XC1 = TCLK1
XC2 = TCLK2
TIOB0
SYNC
TC1XC1S
Timer/Counter
Channel 1
TCLK1
XC0 = TCLK2
TIOA0
TIOA1
XC1
TIOA2
XC2 = TCLK2
TIOB1
SYNC
Timer/Counter
Channel 2
TC2XC2S
XC0 = TCLK0
TCLK2
TIOA2
XC1 = TCLK1
TIOA0
XC2
TIOB2
TIOA1
SYNC
Figure 36-3. Clock Selection
TCCLKS
TIMER_CLOCK1
TIMER_CLOCK2
CLKI
TIMER_CLOCK3
TIMER_CLOCK4
TIMER_CLOCK5
Selected
Clock
XC0
XC1
XC2
BURST
1
605
6249B–ATARM–14-Dec-06
36.5.4
Clock Control
The clock of each counter can be controlled in two different ways: it can be enabled/disabled
and started/stopped. See Figure 36-4.
• 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.
Figure 36-4. Clock Control
Selected
Clock
Trigger
CLKSTA
Q
Q
S
CLKEN
CLKDIS
S
R
R
Counter
Clock
36.5.5
Stop
Event
Disable
Event
TC Operating Modes
Each channel can independently operate in two different modes:
• Capture Mode provides measurement on signals.
• Waveform Mode provides wave generation.
The TC Operating Mode 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.
36.5.6
Trigger
A trigger resets the counter and starts the counter clock. Three types of triggers are common to
both modes, and a fourth external trigger is available to each mode.
The following triggers are common to both modes:
606
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
• 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.
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.
36.5.7
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 36-5 shows the configuration of the TC channel when programmed in Capture Mode.
36.5.8
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.
36.5.9
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.
607
6249B–ATARM–14-Dec-06
Figure 36-5. Capture Mode
608
AT91SAM9263 Preliminary
TCCLKS
CLKSTA
CLKI
TIMER_CLOCK1
CLKEN
CLKDIS
TIMER_CLOCK2
TIMER_CLOCK3
Q
TIMER_CLOCK4
TIMER_CLOCK5
Q
XC0
S
R
S
R
XC1
XC2
LDBSTOP
LDBDIS
BURST
Register C
Capture
Register A
1
Capture
Register B
Compare RC =
16-bit Counter
SWTRG
CLK
OVF
RESET
SYNC
Trig
ABETRG
CPCTRG
ETRGEDG
MTIOB
Edge
Detector
TIOB
INT
CPCS
6249B–ATARM–14-Dec-06
Timer/Counter Channel
LOVRS
LDRBS
COVFS
If RA is Loaded
LDRAS
Edge
Detector
ETRGS
Edge
Detector
TC1_IMR
TIOA
If RA is not loaded
or RB is Loaded
LDRB
TC1_SR
MTIOA
LDRA
AT91SAM9263 Preliminary
36.5.10
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 36-6 shows the configuration of the TC channel when programmed in Waveform Operating Mode.
36.5.11
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.
609
6249B–ATARM–14-Dec-06
Figure 36-6. Waveform Mode
610
AT91SAM9263 Preliminary
TCCLKS
CLKSTA
TIMER_CLOCK1
CLKEN
CLKDIS
ACPC
CLKI
TIMER_CLOCK3
Q
TIMER_CLOCK4
S
CPCDIS
TIMER_CLOCK5
Q
XC0
R
S
ACPA
R
XC1
XC2
CPCSTOP
BURST
Register A
Register B
Register C
Compare RA =
Compare RB =
Compare RC =
WAVSEL
AEEVT
MTIOA
Output Controller
TIMER_CLOCK2
TIOA
ASWTRG
1
16-bit Counter
CLK
RESET
SWTRG
OVF
BCPC
SYNC
Trig
MTIOB
EEVT
BEEVT
CPBS
CPCS
CPAS
COVFS
ETRGS
Edge
Detector
ENETRG
TC1_SR
EEVTEDG
BSWTRG
TIOB
TC1_IMR
Timer/Counter Channel
INT
Output Controller
BCPB
WAVSEL
TIOB
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
36.5.11.1
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 36-7.
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 36-8.
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 36-7. WAVSEL= 00 without trigger
Counter Value
Counter cleared by compare match with 0xFFFF
0xFFFF
RC
RB
RA
Waveform Examples
Time
TIOB
TIOA
611
6249B–ATARM–14-Dec-06
Figure 36-8. 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
36.5.11.2
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 36-9.
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 36-10.
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 36-9. WAVSEL = 10 Without Trigger
Counter Value
0xFFFF
Counter cleared by compare match with RC
RC
RB
RA
Waveform Examples
Time
TIOB
TIOA
612
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Figure 36-10. WAVSEL = 10 With Trigger
Counter Value
0xFFFF
Counter cleared by compare match with RC
Counter cleared by trigger
RC
RB
RA
Waveform Examples
Time
TIOB
TIOA
36.5.11.3
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 36-11.
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 36-12.
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).
613
6249B–ATARM–14-Dec-06
Figure 36-11. WAVSEL = 01 Without Trigger
Counter decremented by compare match with 0xFFFF
Counter Value
0xFFFF
RC
RB
RA
Time
Waveform Examples
TIOB
TIOA
Figure 36-12. 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
Time
Waveform Examples
TIOB
TIOA
36.5.11.4
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 36-13.
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 36-14.
RC Compare can stop the counter clock (CPCSTOP = 1) and/or disable the counter clock (CPCDIS = 1).
614
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Figure 36-13. WAVSEL = 11 Without Trigger
Counter Value
0xFFFF
Counter decremented by compare match with RC
RC
RB
RA
Time
Waveform Examples
TIOB
TIOA
Figure 36-14. WAVSEL = 11 With Trigger
Counter Value
0xFFFF
Counter decremented by compare match with RC
RC
RB
Counter decremented
by trigger
Counter incremented
by trigger
RA
Waveform Examples
Time
TIOB
TIOA
615
6249B–ATARM–14-Dec-06
36.5.12
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 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 compare register B is not used to generate waveforms and subsequently no IRQs. In
this case the TC channel can only generate a waveform on TIOA.
When an external event is defined, it can be used as a trigger by 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.
36.5.13
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.
616
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
36.6
Timer Counter (TC) User Interface
Table 36-4.
Offset
TC Global Memory Map
Channel/Register
Name
Access
Reset Value
0x00
TC Channel 0
See Table 36-5
0x40
TC Channel 1
See Table 36-5
0x80
TC Channel 2
See Table 36-5
0xC0
TC Block Control Register
TC_BCR
Write-only
–
0xC4
TC Block Mode Register
TC_BMR
Read/Write
0
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 36-5. The offset of each of the
channel registers in Table 36-5 is in relation to the offset of the corresponding channel as mentioned in Table 36-5.
Table 36-5.
Offset
TC Channel Memory Map
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
0x14
Register A
TC_RA
Read/Write(1)
0
(1)
0
0x18
Register B
TC_RB
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
0xFC
Reserved
–
–
–
Notes:
Read/Write
1. Read-only if WAVE = 0
617
6249B–ATARM–14-Dec-06
36.6.1
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.
618
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
36.6.2
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
Signal Connected to XC2
0
0
TCLK2
0
1
none
1
0
TIOA0
1
1
TIOA1
619
6249B–ATARM–14-Dec-06
36.6.3
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.
620
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
36.6.4
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
16
LDRB
4
BURST
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.
621
6249B–ATARM–14-Dec-06
• 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
622
Edge
0
0
none
0
1
rising edge of TIOA
1
0
falling edge of TIOA
1
1
each edge of TIOA
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
36.6.5
TC Channel Mode Register: Waveform Mode
Register Name:
TC_CMR
Access Type:
Read/Write
31
30
29
BSWTRG
23
22
21
ASWTRG
15
28
27
BEEVT
20
19
AEEVT
14
WAVE = 1
13
7
6
CPCDIS
CPCSTOP
24
BCPB
18
11
ENETRG
5
25
17
16
ACPC
12
WAVSEL
26
BCPC
ACPA
10
9
EEVT
4
3
BURST
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.
623
6249B–ATARM–14-Dec-06
• 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
Signal selected as external event
TIOB Direction
0
0
TIOB
input (1)
0
1
XC0
output
1
0
XC1
output
1
1
XC2
output
Note:
1. If TIOB is chosen as the external event signal, it is configured as an input and no longer generates waveforms and subsequently no IRQs.
• 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
624
Effect
0
0
none
0
1
set
1
0
clear
1
1
toggle
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
• 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
Effect
0
0
none
0
1
set
1
0
clear
1
1
toggle
625
6249B–ATARM–14-Dec-06
• 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
626
Effect
0
0
none
0
1
set
1
0
clear
1
1
toggle
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
36.6.6
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.
36.6.7
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.
627
6249B–ATARM–14-Dec-06
36.6.8
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.
36.6.9
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.
628
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
36.6.10 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.
629
6249B–ATARM–14-Dec-06
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.
630
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
36.6.11 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.
631
6249B–ATARM–14-Dec-06
36.6.12 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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36.6.13 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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37. Controller Area Network (CAN)
37.1
Description
The CAN controller provides all the features required to implement the serial communication
protocol CAN defined by Robert Bosch GmbH, the CAN specification as referred to by
ISO/11898A (2.0 Part A and 2.0 Part B) for high speeds and ISO/11519-2 for low speeds. The
CAN Controller is able to handle all types of frames (Data, Remote, Error and Overload) and
achieves a bitrate of 1 Mbit/sec.
CAN controller accesses are made through configuration registers. 16 independent message
objects (mailboxes) are implemented.
Any mailbox can be programmed as a reception buffer block (even non-consecutive buffers).
For the reception of defined messages, one or several message objects can be masked without participating in the buffer feature. An interrupt is generated when the buffer is full.
According to the mailbox configuration, the first message received can be locked in the CAN
controller registers until the application acknowledges it, or this message can be discarded by
new received messages.
Any mailbox can be programmed for transmission. Several transmission mailboxes can be
enabled in the same time. A priority can be defined for each mailbox independently.
An internal 16-bit timer is used to stamp each received and sent message. This timer starts
counting as soon as the CAN controller is enabled. This counter can be reset by the application or automatically after a reception in the last mailbox in Time Triggered Mode.
The CAN controller offers optimized features to support the Time Triggered Communication
(TTC) protocol.
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37.2
Block Diagram
Figure 37-1. CAN Block Diagram
Controller Area Network
CANRX
CAN Protocol Controller
PIO
CANTX
Error Counter
Mailbox
Priority
Encoder
Control
&
Status
MB0
MB1
MCK
PMC
MBx
(x = number of mailboxes - 1)
CAN Interrupt
User Interface
Internal Bus
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37.3
Application Block Diagram
Figure 37-2.
37.4
Application Block Diagram
Layers
Implementation
CAN-based Profiles
Software
CAN-based Application Layer
Software
CAN Data Link Layer
CAN Controller
CAN Physical Layer
Transceiver
I/O Lines Description
Table 37-1.
I/O Lines Description
Name
Description
Type
CANRX
CAN Receive Serial Data
Input
CANTX
CAN Transmit Serial Data
Output
37.5
37.5.1
Product Dependencies
I/O Lines
The pins used for interfacing the CAN may be multiplexed with the PIO lines. The programmer
must first program the PIO controller to assign the desired CAN pins to their peripheral function. If I/O lines of the CAN are not used by the application, they can be used for other
purposes by the PIO Controller.
37.5.2
Power Management
The programmer must first enable the CAN clock in the Power Management Controller (PMC)
before using the CAN.
A Low-power Mode is defined for the CAN controller: If the application does not require CAN
operations, the CAN clock can be stopped when not needed and be restarted later. Before
stopping the clock, the CAN Controller must be in Low-power Mode to complete the current
transfer. After restarting the clock, the application must disable the Low-power Mode of the
CAN controller.
37.5.3
Interrupt
The CAN interrupt line is connected on one of the internal sources of the Advanced Interrupt
Controller. Using the CAN interrupt requires the AIC to be programmed first. Note that it is not
recommended to use the CAN interrupt line in edge-sensitive mode.
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37.6
CAN Controller Features
37.6.1
CAN Protocol Overview
The Controller Area Network (CAN) is a multi-master serial communication protocol that efficiently supports real-time control with a very high level of security with bit rates up to 1 Mbit/s.
The CAN protocol supports four different frame types:
• Data frames: They carry data from a transmitter node to the receiver nodes. The overall
maximum data frame length is 108 bits for a standard frame and 128 bits for an extended
frame.
• Remote frames: A destination node can request data from the source by sending a remote
frame with an identifier that matches the identifier of the required data frame. The
appropriate data source node then sends a data frame as a response to this node request.
• Error frames: An error frame is generated by any node that detects a bus error.
• Overload frames: They provide an extra delay between the preceding and the successive
data frames or remote frames.
The Atmel CAN controller provides the CPU with full functionality of the CAN protocol V2.0
Part A and V2.0 Part B. It minimizes the CPU load in communication overhead. The Data Link
Layer and part of the physical layer are automatically handled by the CAN controller itself.
The CPU reads or writes data or messages via the CAN controller mailboxes. An identifier is
assigned to each mailbox. The CAN controller encapsulates or decodes data messages to
build or to decode bus data frames. Remote frames, error frames and overload frames are
automatically handled by the CAN controller under supervision of the software application.
37.6.2
Mailbox Organization
The CAN module has 16 buffers, also called channels or mailboxes. An identifier that corresponds to the CAN identifier is defined for each active mailbox. Message identifiers can match
the standard frame identifier or the extended frame identifier. This identifier is defined for the
first time during the CAN initialization, but can be dynamically reconfigured later so that the
mailbox can handle a new message family. Several mailboxes can be configured with the
same ID.
Each mailbox can be configured in receive or in transmit mode independently. The mailbox
object type is defined in the MOT field of the CAN_MMRx register.
37.6.2.1
638
Message Acceptance Procedure
If the MIDE field in the CAN_MIDx register is set, the mailbox can handle the extended format
identifier; otherwise, the mailbox handles the standard format identifier. Once a new message
is received, its ID is masked with the CAN_MAMx value and compared with the CAN_MIDx
value. If accepted, the message ID is copied to the CAN_MIDx register.
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Figure 37-3. Message Acceptance Procedure
CAN_MAMx
CAN_MIDx
Message Received
&
&
==
No
Message Refused
Yes
Message Accepted
CAN_MFIDx
If a mailbox is dedicated to receiving several messages (a family of messages) with different
IDs, the acceptance mask defined in the CAN_MAMx register must mask the variable part of
the ID family. Once a message is received, the application must decode the masked bits in the
CAN_MIDx. To speed up the decoding, masked bits are grouped in the family ID register
(CAN_MFIDx).
For example, if the following message IDs are handled by the same mailbox:
ID0 101000100100010010000100 0 11 00b
ID1 101000100100010010000100 0 11 01b
ID2 101000100100010010000100 0 11 10b
ID3 101000100100010010000100 0 11 11b
ID4 101000100100010010000100 1 11 00b
ID5 101000100100010010000100 1 11 01b
ID6 101000100100010010000100 1 11 10b
ID7 101000100100010010000100 1 11 11b
The CAN_MIDx and CAN_MAMx of Mailbox x must be initialized to the corresponding values:
CAN_MIDx = 001 101000100100010010000100 x 11 xxb
CAN_MAMx = 001 111111111111111111111111 0 11 00b
If Mailbox x receives a message with ID6, then CAN_MIDx and CAN_MFIDx are set:
CAN_MIDx = 001 101000100100010010000100 1 11 10b
CAN_MFIDx = 00000000000000000000000000000110b
If the application associates a handler for each message ID, it may define an array of pointers
to functions:
void (*pHandler[8])(void);
When a message is received, the corresponding handler can be invoked using CAN_MFIDx
register and there is no need to check masked bits:
unsigned int MFID0_register;
MFID0_register = Get_CAN_MFID0_Register();
// Get_CAN_MFID0_Register() returns the value of the CAN_MFID0 register
pHandler[MFID0_register]();
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37.6.2.2
Receive Mailbox
When the CAN module receives a message, it looks for the first available mailbox with the lowest number and compares the received message ID with the mailbox ID. If such a mailbox is
found, then the message is stored in its data registers. Depending on the configuration, the
mailbox is disabled as long as the message has not been acknowledged by the application
(Receive only), or, if new messages with the same ID are received, then they overwrite the
previous ones (Receive with overwrite).
It is also possible to configure a mailbox in Consumer Mode. In this mode, after each transfer
request, a remote frame is automatically sent. The first answer received is stored in the corresponding mailbox data registers.
Several mailboxes can be chained to receive a buffer. They must be configured with the same
ID in Receive Mode, except for the last one, which can be configured in Receive with Overwrite Mode. The last mailbox can be used to detect a buffer overflow.
Mailbox Object Type
Receive
Receive with overwrite
Consumer
37.6.2.3
Description
The first message received is stored in mailbox data registers. Data remain available until the
next transfer request.
The last message received is stored in mailbox data register. The next message always
overwrites the previous one. The application has to check whether a new message has not
overwritten the current one while reading the data registers.
A remote frame is sent by the mailbox. The answer received is stored in mailbox data register.
This extends Receive mailbox features. Data remain available until the next transfer request.
Transmit Mailbox
When transmitting a message, the message length and data are written to the transmit mailbox with the correct identifier. For each transmit mailbox, a priority is assigned. The controller
automatically sends the message with the highest priority first (set with the field PRIOR in
CAN_MMRx register).
It is also possible to configure a mailbox in Producer Mode. In this mode, when a remote frame
is received, the mailbox data are sent automatically. By enabling this mode, a producer can be
done using only one mailbox instead of two: one to detect the remote frame and one to send
the answer.
Mailbox Object Type
640
Description
Transmit
The message stored in the mailbox data registers will try to win the bus arbitration immediately
or later according to or not the Time Management Unit configuration (see Section 37.6.3).
The application is notified that the message has been sent or aborted.
Producer
The message prepared in the mailbox data registers will be sent after receiving the next remote
frame. This extends transmit mailbox features.
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37.6.3
Time Management Unit
The CAN Controller integrates a free-running 16-bit internal timer. The counter is driven by the
bit clock of the CAN bus line. It is enabled when the CAN controller is enabled (CANEN set in
the CAN_MR register). It is automatically cleared in the following cases:
• after a reset
• when the CAN controller is in Low-power Mode is enabled (LPM bit set in the CAN_MR and
SLEEP bit set in the CAN_SR)
• after a reset of the CAN controller (CANEN bit in the CAN_MR register)
• in Time-triggered Mode, when a message is accepted by the last mailbox (rising edge of
the MRDY signal in the CAN_MSRlast_mailbox_number register).
The application can also reset the internal timer by setting TIMRST in the CAN_TCR register.
The current value of the internal timer is always accessible by reading the CAN_TIM register.
When the timer rolls-over from FFFFh to 0000h, TOVF (Timer Overflow) signal in the CAN_SR
register is set. TOVF bit in the CAN_SR register is cleared by reading the CAN_SR register.
Depending on the corresponding interrupt mask in the CAN_IMR register, an interrupt is generated while TOVF is set.
In a CAN network, some CAN devices may have a larger counter. In this case, the application
can also decide to freeze the internal counter when the timer reaches FFFFh and to wait for a
restart condition from another device. This feature is enabled by setting TIMFRZ in the
CAN_MR register. The CAN_TIM register is frozen to the FFFFh value. A clear condition
described above restarts the timer. A timer overflow (TOVF) interrupt is triggered.
To monitor the CAN bus activity, the CAN_TIM register is copied to the CAN _TIMESTP register after each start of frame or end of frame and a TSTP interrupt is triggered. If TEOF bit in
the CAN_MR register is set, the value is captured at each End Of Frame, else it is captured at
each Start Of Frame. Depending on the corresponding mask in the CAN_IMR register, an
interrupt is generated while TSTP is set in the CAN_SR. TSTP bit is cleared by reading the
CAN_SR register.
The time management unit can operate in one of the two following modes:
• Timestamping mode: The value of the internal timer is captured at each Start Of Frame or
each End Of Frame
• Time Triggered mode: A mailbox transfer operation is triggered when the internal timer
reaches the mailbox trigger.
Timestamping Mode is enabled by clearing TTM field in the CAN_MR register. Time Triggered
Mode is enabled by setting TTM field in the CAN_MR register.
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37.6.4
37.6.4.1
CAN 2.0 Standard Features
CAN Bit Timing Configuration
All controllers on a CAN bus must have the same bit rate and bit length. At different clock frequencies of the individual controllers, the bit rate has to be adjusted by the time segments.
The CAN protocol specification partitions the nominal bit time into four different segments:
Figure 37-4. Partition of the CAN Bit Time
NOMINAL BIT TIME
SYNC_SEG
PROP_SEG
PHASE_SEG1
PHASE_SEG2
Sample Point
TIME QUANTUM:
The TIME QUANTUM (TQ) is a fixed unit of time derived from the MCK period. The total number of TIME QUANTA in a bit time is programmable from 8 to 25.
SYNC SEG: SYNChronization Segment.
This part of the bit time is used to synchronize the various nodes on the bus. An edge is
expected to lie within this segment. It is 1 TQ long.
PROP SEG: PROPagation Segment.
This part of the bit time is used to compensate for the physical delay times within the network.
It is twice the sum of the signal’s propagation time on the bus line, the input comparator delay,
and the output driver delay. It is programmable to be 1,2,..., 8 TQ long.
This parameter is defined in the PROPAG field of the ”CAN Baudrate Register”.
PHASE SEG1, PHASE SEG2: PHASE Segment 1 and 2.
The Phase-Buffer-Segments are used to compensate for edge phase errors. These segments
can be lengthened (PHASE SEG1) or shortened (PHASE SEG2) by resynchronization.
Phase Segment 1 is programmable to be 1,2,..., 8 TQ long.
Phase Segment 2 length has to be at least as long as the Information Processing Time (IPT)
and may not be more than the length of Phase Segment 1.
These parameters are defined in the PHASE1 and PHASE2 fields of the ”CAN Baudrate
Register”.
INFORMATION PROCESSING TIME:
The Information Processing Time (IPT) is the time required for the logic to determine the bit
level of a sampled bit. The IPT begins at the sample point, is measured in TQ and is fixed at
2 TQ for the Atmel CAN. Since Phase Segment 2 also begins at the sample point and is the
last segment in the bit time, PHASE SEG2 shall not be less than the IPT.
SAMPLE POINT:
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The SAMPLE POINT is the point in time at which the bus level is read and interpreted as the
value of that respective bit. Its location is at the end of PHASE_SEG1.
SJW: ReSynchronization Jump Width.
The ReSynchronization Jump Width defines the limit to the amount of lengthening or shortening of the Phase Segments.
SJW is programmable to be the minimum of PHASE SEG1 and 4 TQ.
If the SMP field in the CAN_BR register is set, then the incoming bit stream is sampled three
times with a period of half a CAN clock period, centered on sample point.
In the CAN controller, the length of a bit on the CAN bus is determined by the parameters
(BRP, PROPAG, PHASE1 and PHASE2).
t BIT = t CSC + t PRS + t PHS1 + t PHS2
The time quantum is calculated as follows:
t CSC = ( BRP + 1 ) ⁄ MCK
Note: The BRP field must be within the range [1, 0x7F], i.e., BRP = 0 is not authorized.
t PRS = t CSC × ( PROPAG + 1 )
t PHS1 = t CSC × ( PHASE1 + 1 )
t PHS2 = t CSC × ( PHASE2 + 1 )
To compensate for phase shifts between clock oscillators of different controllers on the bus,
the CAN controller must resynchronize on any relevant signal edge of the current transmission. The resynchronization shortens or lengthens the bit time so that the position of the
sample point is shifted with regard to the detected edge. The resynchronization jump width
(SJW) defines the maximum of time by which a bit period may be shortened or lengthened by
resynchronization.
t SJW = t CSC × ( SJW + 1 )
Figure 37-5. CAN Bit Timing
MCK
CAN Clock
tCSC
tPRS
tPHS1
tPHS2
NOMINAL BIT TIME
SYNC_
SEG
PROP_SEG
PHASE_SEG1
PHASE_SEG2
Sample Point
Transmission Point
Example of bit timing determination for CAN baudrate of 500 Kbit/s:
MCK = 48MHz
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CAN baudrate= 500kbit/s => bit time= 2us
Delay of the bus driver: 50 ns
Delay of the receiver: 30ns
Delay of the bus line (20m): 110ns
The total number of time quanta in a bit time must be comprised between 8
and 25. If we fix the bit time to 16 time quanta:
Tcsc = 1 time quanta = bit time / 16 = 125 ns
=> BRP = (Tcsc x MCK) - 1 = 5
The propagation segment time is equal to twice the sum of the signal’s
propagation time on the bus line, the receiver delay and the output driver
delay:
Tprs = 2 * (50+30+110) ns = 380 ns = 3 Tcsc
=> PROPAG = Tprs/Tcsc - 1 = 2
The remaining time for the two phase segments is:
Tphs1 + Tphs2 = bit time - Tcsc - Tprs = (16 - 1 - 3)Tcsc
Tphs1 + Tphs2 = 12 Tcsc
Because this number is even, we choose Tphs2 = Tphs1 (else we would choose
Tphs2 = Tphs1 + Tcsc)
Tphs1 = Tphs2 = (12/2) Tcsc = 6 Tcsc
=> PHASE1 = PHASE2 = Tphs1/Tcsc - 1 = 5
The resynchronization jump width must be comprised between 1 Tcsc and the
minimum of 4 Tcsc and Tphs1. We choose its maximum value:
Tsjw = Min(4 Tcsc,Tphs1) = 4 Tcsc
=> SJW = Tsjw/Tcsc - 1 = 3
Finally: CAN_BR = 0x00053255
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CAN Bus Synchronization
Two types of synchronization are distinguished: “hard synchronization” at the start of a frame
and “resynchronization” inside a frame. After a hard synchronization, the bit time is restarted
with the end of the SYNC_SEG segment, regardless of the phase error. Resynchronization
causes a reduction or increase in the bit time so that the position of the sample point is shifted
with respect to the detected edge.
The effect of resynchronization is the same as that of hard synchronization when the magnitude of the phase error of the edge causing the resynchronization is less than or equal to the
programmed value of the resynchronization jump width (tSJW).
When the magnitude of the phase error is larger than the resynchronization jump width and
• the phase error is positive, then PHASE_SEG1 is lengthened by an amount equal to the
resynchronization jump width.
• the phase error is negative, then PHASE_SEG2 is shortened by an amount equal to the
resynchronization jump width.
Figure 37-6. CAN Resynchronization
THE PHASE ERROR IS POSITIVE
(the transmitter is slower than the receiver)
Nominal
Sample point
Sample point
after resynchronization
Received
data bit
Nominal bit time
(before resynchronization)
SYNC_
SEG
PROP_SEG
PHASE_SEG1 PHASE_SEG2
Phase error (max Tsjw)
Phase error
Bit time with
resynchronization
SYNC_
SEG
SYNC_
SEG
PROP_SEG
PHASE_SEG1
THE PHASE ERROR IS NEGATIVE
(the transmitter is faster than the receiver)
PHASE_SEG2
Sample point
after resynchronization
SYNC_
SEG
Nominal
Sample point
Received
data bit
Nominal bit time
(before resynchronization)
PHASE_SEG2
SYNC_
SEG
PROP_SEG
PHASE_SEG1 PHASE_SEG2
SYNC_
SEG
Phase error
Bit time with
resynchronization
PHASE_ SYNC_
SEG2 SEG
PROP_SEG
PHASE_SEG1 PHASE_SEG2
SYNC_
SEG
Phase error (max Tsjw)
Autobaud Mode
The autobaud feature is enabled by setting the ABM field in the CAN_MR register. In this
mode, the CAN controller is only listening to the line without acknowledging the received messages. It can not send any message. The errors flags are updated. The bit timing can be
adjusted until no error occurs (good configuration found). In this mode, the error counters are
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frozen. To go back to the standard mode, the ABM bit must be cleared in the CAN_MR
register.
37.6.4.2
Error Detection
There are five different error types that are not mutually exclusive. Each error concerns only
specific fields of the CAN data frame (refer to the Bosch CAN specification for their
correspondence):
• CRC error (CERR bit in the CAN_SR register): With the CRC, the transmitter calculates a
checksum for the CRC bit sequence from the Start of Frame bit until the end of the Data
Field. This CRC sequence is transmitted in the CRC field of the Data or Remote Frame.
• Bit-stuffing error (SERR bit in the CAN_SR register): If a node detects a sixth consecutive
equal bit level during the bit-stuffing area of a frame, it generates an Error Frame starting
with the next bit-time.
• Bit error (BERR bit in CAN_SR register): A bit error occurs if a transmitter sends a
dominant bit but detects a recessive bit on the bus line, or if it sends a recessive bit but
detects a dominant bit on the bus line. An error frame is generated and starts with the next
bit time.
• Form Error (FERR bit in the CAN_SR register): If a transmitter detects a dominant bit in
one of the fix-formatted segments CRC Delimiter, ACK Delimiter or End of Frame, a form
error has occurred and an error frame is generated.
• Acknowledgment error (AERR bit in the CAN_SR register): The transmitter checks the
Acknowledge Slot, which is transmitted by the transmitting node as a recessive bit,
contains a dominant bit. If this is the case, at least one other node has received the frame
correctly. If not, an Acknowledge Error has occurred and the transmitter will start in the next
bit-time an Error Frame transmission.
Fault Confinement
To distinguish between temporary and permanent failures, every CAN controller has two error
counters: REC (Receive Error Counter) and TEC (Transmit Error Counter). The counters are
incremented upon detected errors and respectively are decremented upon correct transmissions or receptions. Depending on the counter values, the state of the node changes: the
initial state of the CAN controller is Error Active, meaning that the controller can send Error
Active flags. The controller changes to the Error Passive state if there is an accumulation of
errors. If the CAN controller fails or if there is an extreme accumulation of errors, there is a
state transition to Bus Off.
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Figure 37-7. Line Error Mode
Init
TEC > 127
or
REC > 127
ERROR
PASSIVE
ERROR
ACTIVE
TEC < 127
and
REC < 127
128 occurences of 11 consecutive recessive bits
or
CAN controller reset
BUS OFF
TEC > 255
An error active unit takes part in bus communication and sends an active error frame when the
CAN controller detects an error.
An error passive unit cannot send an active error frame. It takes part in bus communication,
but when an error is detected, a passive error frame is sent. Also, after a transmission, an
error passive unit waits before initiating further transmission.
A bus off unit is not allowed to have any influence on the bus.
For fault confinement, two errors counters (TEC and REC) are implemented. These counters
are accessible via the CAN_ECR register. The state of the CAN controller is automatically
updated according to these counter values. If the CAN controller is in Error Active state, then
the ERRA bit is set in the CAN_SR register. The corresponding interrupt is pending while the
interrupt is not masked in the CAN_IMR register. If the CAN controller is in Error Passive
Mode, then the ERRP bit is set in the CAN_SR register and an interrupt remains pending while
the ERRP bit is set in the CAN_IMR register. If the CAN is in Bus-off Mode, then the BOFF bit
is set in the CAN_SR register. As for ERRP and ERRA, an interrupt is pending while the BOFF
bit is set in the CAN_IMR register.
When one of the error counters values exceeds 96, an increased error rate is indicated to the
controller through the WARN bit in CAN_SR register, but the node remains error active. The
corresponding interrupt is pending while the interrupt is set in the CAN_IMR register.
Refer to the Bosch CAN specification v2.0 for details on fault confinement.
37.6.4.3
Overload
The overload frame is provided to request a delay of the next data or remote frame by the
receiver node (“Request overload frame”) or to signal certain error conditions (“Reactive overload frame”) related to the intermission field respectively.
Reactive overload frames are transmitted after detection of the following error conditions:
• Detection of a dominant bit during the first two bits of the intermission field
• Detection of a dominant bit in the last bit of EOF by a receiver, or detection of a dominant
bit by a receiver or a transmitter at the last bit of an error or overload frame delimiter
The CAN controller can generate a request overload frame automatically after each message
sent to one of the CAN controller mailboxes. This feature is enabled by setting the OVL bit in
the CAN_MR register.
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Reactive overload frames are automatically handled by the CAN controller even if the OVL bit
in the CAN_MR register is not set. An overload flag is generated in the same way as an error
flag, but error counters do not increment.
37.6.5
Low-power Mode
In Low-power Mode, the CAN controller cannot send or receive messages. All mailboxes are
inactive.
In Low-power Mode, the SLEEP signal in the CAN_SR register is set; otherwise, the WAKEUP
signal in the CAN_SR register is set. These two fields are exclusive except after a CAN controller reset (WAKEUP and SLEEP are stuck at 0 after a reset). After power-up reset, the Lowpower Mode is disabled and the WAKEUP bit is set in the CAN_SR register only after detection of 11 consecutive recessive bits on the bus.
37.6.5.1
Enabling Low-power Mode
A software application can enable Low-power Mode by setting the LPM bit in the CAN_MR
global register. The CAN controller enters Low-power Mode once all pending transmit messages are sent.
When the CAN controller enters Low-power Mode, the SLEEP signal in the CAN_SR register
is set. Depending on the corresponding mask in the CAN_IMR register, an interrupt is generated while SLEEP is set.
The SLEEP signal in the CAN_SR register is automatically cleared once WAKEUP is set. The
WAKEUP signal is automatically cleared once SLEEP is set.
Reception is disabled while the SLEEP signal is set to one in the CAN_SR register. It is important to note that those messages with higher priority than the last message transmitted can be
received between the LPM command and entry in Low-power Mode.
Once in Low-power Mode, the CAN controller clock can be switched off by programming the
chip’s Power Management Controller (PMC). The CAN controller drains only the static current.
Error counters are disabled while the SLEEP signal is set to one.
Thus, to enter Low-power Mode, the software application must:
– Set LPM field in the CAN_MR register
– Wait for SLEEP signal rising
Now the CAN Controller clock can be disabled. This is done by programming the Power Management Controller (PMC).
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Figure 37-8. Enabling Low-power Mode
Arbitration lost
Mailbox 1
CAN BUS
Mailbox 3
LPEN= 1
LPM
(CAN_MR)
SLEEP
(CAN_SR)
WAKEUP
(CAN_SR)
MRDY
(CAN_MSR1)
MRDY
(CAN_MSR3)
CAN_TIM
37.6.5.2
0x0
Disabling Low-power Mode
The CAN controller can be awake after detecting a CAN bus activity. Bus activity detection is
done by an external module that may be embedded in the chip. When it is notified of a CAN
bus activity, the software application disables Low-power Mode by programming the CAN
controller.
To disable Low-power Mode, the software application must:
– Enable the CAN Controller clock. This is done by programming the Power
Management Controller (PMC).
– Clear the LPM field in the CAN_MR register
The CAN controller synchronizes itself with the bus activity by checking for eleven consecutive
“recessive” bits. Once synchronized, the WAKEUP signal in the CAN_SR register is set.
Depending on the corresponding mask in the CAN_IMR register, an interrupt is generated
while WAKEUP is set. The SLEEP signal in the CAN_SR register is automatically cleared
once WAKEUP is set. WAKEUP signal is automatically cleared once SLEEP is set.
If no message is being sent on the bus, then the CAN controller is able to send a message
eleven bit times after disabling Low-power Mode.
If there is bus activity when Low-power mode is disabled, the CAN controller is synchronized
with the bus activity in the next interframe. The previous message is lost (see Figure 37-9).
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Figure 37-9. Disabling Low-power Mode
Bus Activity Detected
CAN BUS
Message lost
Message x
Interframe synchronization
LPM
(CAN_MR)
SLEEP
(CAN_SR)
WAKEUP
(CAN_SR)
MRDY
(CAN_MSRx)
37.7
37.7.1
Functional Description
CAN Controller Initialization
After power-up reset, the CAN controller is disabled. The CAN controller clock must be activated by the Power Management Controller (PMC) and the CAN controller interrupt line must
be enabled by the interrupt controller (AIC).
The CAN controller must be initialized with the CAN network parameters. The CAN_BR register defines the sampling point in the bit time period. CAN_BR must be set before the CAN
controller is enabled by setting the CANEN field in the CAN_MR register.
The CAN controller is enabled by setting the CANEN flag in the CAN_MR register. At this
stage, the internal CAN controller state machine is reset, error counters are reset to 0, error
flags are reset to 0.
Once the CAN controller is enabled, bus synchronization is done automatically by scanning
eleven recessive bits. The WAKEUP bit in the CAN_SR register is automatically set to 1 when
the CAN controller is synchronized (WAKEUP and SLEEP are stuck at 0 after a reset).
The CAN controller can start listening to the network in Autobaud Mode. In this case, the error
counters are locked and a mailbox may be configured in Receive Mode. By scanning error
flags, the CAN_BR register values synchronized with the network. Once no error has been
detected, the application disables the Autobaud Mode, clearing the ABM field in the CAN_MR
register.
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Figure 37-10. Possible Initialization Procedure
Enable CAN Controller Clock
(PMC)
Enable CAN Controller Interrupt Line
(AIC)
Configure a Mailbox in Reception Mode
Change CAN_BR value
(ABM == 1 and CANEN == 1)
Errors ?
Yes
(CAN_SR or CAN_MSRx)
No
ABM = 0 and CANEN = 0
CANEN = 1 (ABM == 0)
End of Initialization
37.7.2
CAN Controller Interrupt Handling
There are two different types of interrupts. One type of interrupt is a message-object related
interrupt, the other is a system interrupt that handles errors or system-related interrupt
sources.
All interrupt sources can be masked by writing the corresponding field in the CAN_IDR register. They can be unmasked by writing to the CAN_IER register. After a power-up reset, all
interrupt sources are disabled (masked). The current mask status can be checked by reading
the CAN_IMR register.
The CAN_SR register gives all interrupt source states.
The following events may initiate one of the two interrupts:
• Message object interrupt
– Data registers in the mailbox object are available to the application. In Receive
Mode, a new message was received. In Transmit Mode, a message was
transmitted successfully.
– A sent transmission was aborted.
• System interrupts
– Bus-off interrupt: The CAN module enters the bus-off state.
– Error-passive interrupt: The CAN module enters Error Passive Mode.
– Error-active Mode: The CAN module is neither in Error Passive Mode nor in Busoff mode.
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– Warn Limit interrupt: The CAN module is in Error-active Mode, but at least one of
its error counter value exceeds 96.
– Wake-up interrupt: This interrupt is generated after a wake-up and a bus
synchronization.
– Sleep interrupt: This interrupt is generated after a Low-power Mode enable once
all pending messages in transmission have been sent.
– Internal timer counter overflow interrupt: This interrupt is generated when the
internal timer rolls over.
– Timestamp interrupt: This interrupt is generated after the reception or the
transmission of a start of frame or an end of frame. The value of the internal
counter is copied in the CAN_TIMESTP register.
All interrupts are cleared by clearing the interrupt source except for the internal timer counter
overflow interrupt and the timestamp interrupt. These interrupts are cleared by reading the
CAN_SR register.
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37.7.3
CAN Controller Message Handling
37.7.3.1
Receive Handling
Two modes are available to configure a mailbox to receive messages. In Receive Mode, the
first message received is stored in the mailbox data register. In Receive with Overwrite
Mode, the last message received is stored in the mailbox.
Simple Receive Mailbox
A mailbox is in Receive Mode once the MOT field in the CAN_MMRx register has been configured. Message ID and Message Acceptance Mask must be set before the Receive Mode is
enabled.
After Receive Mode is enabled, the MRDY flag in the CAN_MSR register is automatically
cleared until the first message is received. When the first message has been accepted by the
mailbox, the MRDY flag is set. An interrupt is pending for the mailbox while the MRDY flag is
set. This interrupt can be masked depending on the mailbox flag in the CAN_IMR global
register.
Message data are stored in the mailbox data register until the software application notifies that
data processing has ended. This is done by asking for a new transfer command, setting the
MTCR flag in the CAN_MCRx register. This automatically clears the MRDY signal.
The MMI flag in the CAN_MSRx register notifies the software that a message has been lost by
the mailbox. This flag is set when messages are received while MRDY is set in the
CAN_MSRx register. This flag is cleared by reading the CAN_MSRs register. A receive mailbox prevents from overwriting the first message by new ones while MRDY flag is set in the
CAN_MSRx register. See Figure 37-11.
Figure 37-11. Receive Mailbox
Message ID = CAN_MIDx
CAN BUS
Message 1
Message 2 lost
Message 3
MRDY
(CAN_MSRx)
MMI
(CAN_MSRx)
(CAN_MDLx
CAN_MDHx)
Message 1
Message 3
MTCR
(CAN_MCRx)
Reading CAN_MSRx
Reading CAN_MDHx & CAN_MDLx
Writing CAN_MCRx
Note:
In the case of ARM architecture, CAN_MSRx, CAN_MDLx, CAN_MDHx can be read using an optimized ldm assembler
instruction.
Receive with Overwrite Mailbox
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A mailbox is in Receive with Overwrite Mode once the MOT field in the CAN_MMRx register
has been configured. Message ID and Message Acceptance masks must be set before
Receive Mode is enabled.
After Receive Mode is enabled, the MRDY flag in the CAN_MSR register is automatically
cleared until the first message is received. When the first message has been accepted by the
mailbox, the MRDY flag is set. An interrupt is pending for the mailbox while the MRDY flag is
set. This interrupt is masked depending on the mailbox flag in the CAN_IMR global register.
If a new message is received while the MRDY flag is set, this new message is stored in the
mailbox data register, overwriting the previous message. The MMI flag in the CAN_MSRx register notifies the software that a message has been dropped by the mailbox. This flag is
cleared when reading the CAN_MSRx register.
The CAN controller may store a new message in the CAN data registers while the application
reads them. To check that CAN_MDHx and CAN_MDLx do not belong to different messages,
the application must check the MMI field in the CAN_MSRx register before and after reading
CAN_MDHx and CAN_MDLx. If the MMI flag is set again after the data registers have been
read, the software application has to re-read CAN_MDHx and CAN_MDLx (see Figure 37-12).
Figure 37-12. Receive with Overwrite Mailbox
Message ID = CAN_MIDx
CAN BUS
Message 1
Message 2
Message 3
Message 4
MRDY
(CAN_MSRx)
MMI
(CAN_MSRx)
(CAN_MDLx
CAN_MDHx)
Message 1
Message 2
Message 3
Message 4
MTCR
(CAN_MCRx)
Reading CAN_MSRx
Reading CAN_MDHx & CAN_MDLx
Writing CAN_MCRx
Chaining Mailboxes
Several mailboxes may be used to receive a buffer split into several messages with the same
ID. In this case, the mailbox with the lowest number is serviced first. In the receive and receive
with overwrite modes, the field PRIOR in the CAN_MMRx register has no effect. If Mailbox 0
and Mailbox 5 accept messages with the same ID, the first message is received by Mailbox 0
and the second message is received by Mailbox 5. Mailbox 0 must be configured in Receive
Mode (i.e., the first message received is considered) and Mailbox 5 must be configured in
Receive with Overwrite Mode. Mailbox 0 cannot be configured in Receive with Overwrite
Mode; otherwise, all messages are accepted by this mailbox and Mailbox 5 is never serviced.
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If several mailboxes are chained to receive a buffer split into several messages, all mailboxes
except the last one (with the highest number) must be configured in Receive Mode. The first
message received is handled by the first mailbox, the second one is refused by the first mailbox and accepted by the second mailbox, the last message is accepted by the last mailbox
and refused by previous ones (see Figure 37-13).
Figure 37-13. Chaining Three Mailboxes to Receive a Buffer Split into Three Messages
Buffer split in 3 messages
CAN BUS
Message s1
Message s2
Message s3
MRDY
(CAN_MSRx)
MMI
(CAN_MSRx)
MRDY
(CAN_MSRy)
MMI
(CAN_MSRy)
MRDY
(CAN_MSRz)
MMI
(CAN_MSRz)
Reading CAN_MSRx, CAN_MSRy and CAN_MSRz
Reading CAN_MDH & CAN_MDL for mailboxes x, y and z
Writing MBx MBy MBz in CAN_TCR
If the number of mailboxes is not sufficient (the MMI flag of the last mailbox raises), the user
must read each data received on the last mailbox in order to retrieve all the messages of the
buffer split (see Figure 37-14).
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Figure 37-14. Chaining Three Mailboxes to Receive a Buffer Split into Four Messages
Buffer split in 4 messages
CAN BUS
Message s1
Message s2
Message s3
Message s4
MRDY
(CAN_MSRx)
MMI
(CAN_MSRx)
MRDY
(CAN_MSRy)
MMI
(CAN_MSRy)
MRDY
(CAN_MSRz)
MMI
(CAN_MSRz)
Reading CAN_MSRx, CAN_MSRy and CAN_MSRz
Reading CAN_MDH & CAN_MDL for mailboxes x, y and z
Writing MBx MBy MBz in CAN_TCR
37.7.3.2
Transmission Handling
A mailbox is in Transmit Mode once the MOT field in the CAN_MMRx register has been configured. Message ID and Message Acceptance mask must be set before Receive Mode is
enabled.
After Transmit Mode is enabled, the MRDY flag in the CAN_MSR register is automatically set
until the first command is sent. When the MRDY flag is set, the software application can prepare a message to be sent by writing to the CAN_MDx registers. The message is sent once
the software asks for a transfer command setting the MTCR bit and the message data length
in the CAN_MCRx register.
The MRDY flag remains at zero as long as the message has not been sent or aborted. It is
important to note that no access to the mailbox data register is allowed while the MRDY flag is
cleared. An interrupt is pending for the mailbox while the MRDY flag is set. This interrupt can
be masked depending on the mailbox flag in the CAN_IMR global register.
It is also possible to send a remote frame setting the MRTR bit instead of setting the MDLC
field. The answer to the remote frame is handled by another reception mailbox. In this case,
the device acts as a consumer but with the help of two mailboxes. It is possible to handle the
remote frame emission and the answer reception using only one mailbox configured in Consumer Mode. Refer to the section ”Remote Frame Handling” on page 657.
Several messages can try to win the bus arbitration in the same time. The message with the
highest priority is sent first. Several transfer request commands can be generated at the same
time by setting MBx bits in the CAN_TCR register. The priority is set in the PRIOR field of the
CAN_MMRx register. Priority 0 is the highest priority, priority 15 is the lowest priority. Thus it is
possible to use a part of the message ID to set the PRIOR field. If two mailboxes have the
same priority, the message of the mailbox with the lowest number is sent first. Thus if mailbox
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0 and mailbox 5 have the same priority and have a message to send at the same time, then
the message of the mailbox 0 is sent first.
Setting the MACR bit in the CAN_MCRx register aborts the transmission. Transmission for
several mailboxes can be aborted by writing MBx fields in the CAN_MACR register. If the
message is being sent when the abort command is set, then the application is notified by the
MRDY bit set and not the MABT in the CAN_MSRx register. Otherwise, if the message has
not been sent, then the MRDY and the MABT are set in the CAN_MSR register.
When the bus arbitration is lost by a mailbox message, the CAN controller tries to win the next
bus arbitration with the same message if this one still has the highest priority. Messages to be
sent are re-tried automatically until they win the bus arbitration. This feature can be disabled
by setting the bit DRPT in the CAN_MR register. In this case if the message was not sent the
first time it was transmitted to the CAN transceiver, it is automatically aborted. The MABT flag
is set in the CAN_MSRx register until the next transfer command.
Figure 37-15 shows three MBx message attempts being made (MRDY of MBx set to 0).
The first MBx message is sent, the second is aborted and the last one is trying to be aborted
but too late because it has already been transmitted to the CAN transceiver.
Figure 37-15. Transmitting Messages
CAN BUS
MBx message
MBx message
MRDY
(CAN_MSRx)
MABT
(CAN_MSRx)
MTCR
(CAN_MCRx)
MACR
(CAN_MCRx)
Abort MBx message
Try to Abort MBx message
Reading CAN_MSRx
Writing CAN_MDHx &
CAN_MDLx
37.7.3.3
Remote Frame Handling
Producer/consumer model is an efficient means of handling broadcasted messages. The push
model allows a producer to broadcast messages; the pull model allows a customer to ask for
messages.
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Figure 37-16. Producer / Consumer Model
Producer
Request
PUSH MODEL
CAN Data Frame
Consumer
Indication(s)
PULL MODEL
Producer
Indications
Response
Consumer
CAN Remote Frame
Request(s)
CAN Data Frame
Confirmation(s)
In Pull Mode, a consumer transmits a remote frame to the producer. When the producer
receives a remote frame, it sends the answer accepted by one or many consumers. Using
transmit and receive mailboxes, a consumer must dedicate two mailboxes, one in Transmit
Mode to send remote frames, and at least one in Receive Mode to capture the producer’s
answer. The same structure is applicable to a producer: one reception mailbox is required to
get the remote frame and one transmit mailbox to answer.
Mailboxes can be configured in Producer or Consumer Mode. A lonely mailbox can handle the
remote frame and the answer. With 16 mailboxes, the CAN controller can handle 16 independent producers/consumers.
Producer Configuration
A mailbox is in Producer Mode once the MOT field in the CAN_MMRx register has been configured. Message ID and Message Acceptance masks must be set before Receive Mode is
enabled.
After Producer Mode is enabled, the MRDY flag in the CAN_MSR register is automatically set
until the first transfer command. The software application prepares data to be sent by writing
to the CAN_MDHx and the CAN_MDLx registers, then by setting the MTCR bit in the
CAN_MCRx register. Data is sent after the reception of a remote frame as soon as it wins the
bus arbitration.
The MRDY flag remains at zero as long as the message has not been sent or aborted. No
access to the mailbox data register can be done while MRDY flag is cleared. An interrupt is
pending for the mailbox while the MRDY flag is set. This interrupt can be masked according to
the mailbox flag in the CAN_IMR global register.
If a remote frame is received while no data are ready to be sent (signal MRDY set in the
CAN_MSRx register), then the MMI signal is set in the CAN_MSRx register. This bit is cleared
by reading the CAN_MSRx register.
The MRTR field in the CAN_MSRx register has no meaning. This field is used only when using
Receive and Receive with Overwrite modes.
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After a remote frame has been received, the mailbox functions like a transmit mailbox. The
message with the highest priority is sent first. The transmitted message may be aborted by
setting the MACR bit in the CAN_MCR register. Please refer to the section ”Transmission
Handling” on page 656.
Figure 37-17. Producer Handling
Remote Frame
CAN BUS
Message 1
Remote Frame
Remote Frame
Message 2
MRDY
(CAN_MSRx)
MMI
(CAN_MSRx)
Reading CAN_MSRx
MTCR
(CAN_MCRx)
(CAN_MDLx
CAN_MDHx)
Message 1
Message 2
Consumer Configuration
A mailbox is in Consumer Mode once the MOT field in the CAN_MMRx register has been configured. Message ID and Message Acceptance masks must be set before Receive Mode is
enabled.
After Consumer Mode is enabled, the MRDY flag in the CAN_MSR register is automatically
cleared until the first transfer request command. The software application sends a remote
frame by setting the MTCR bit in the CAN_MCRx register or the MBx bit in the global
CAN_TCR register. The application is notified of the answer by the MRDY flag set in the
CAN_MSRx register. The application can read the data contents in the CAN_MDHx and
CAN_MDLx registers. An interrupt is pending for the mailbox while the MRDY flag is set. This
interrupt can be masked according to the mailbox flag in the CAN_IMR global register.
The MRTR bit in the CAN_MCRx register has no effect. This field is used only when using
Transmit Mode.
After a remote frame has been sent, the consumer mailbox functions as a reception mailbox.
The first message received is stored in the mailbox data registers. If other messages intended
for this mailbox have been sent while the MRDY flag is set in the CAN_MSRx register, they
will be lost. The application is notified by reading the MMI field in the CAN_MSRx register. The
read operation automatically clears the MMI flag.
If several messages are answered by the Producer, the CAN controller may have one mailbox
in consumer configuration, zero or several mailboxes in Receive Mode and one mailbox in
Receive with Overwrite Mode. In this case, the consumer mailbox must have a lower number
than the Receive with Overwrite mailbox. The transfer command can be triggered for all mailboxes at the same time by setting several MBx fields in the CAN_TCR register.
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Figure 37-18. Consumer Handling
Remote Frame
CAN BUS
Message x
Remote Frame
Message y
MRDY
(CAN_MSRx)
MMI
(CAN_MSRx)
MTCR
(CAN_MCRx)
(CAN_MDLx
CAN_MDHx)
37.7.4
Message y
Message x
CAN Controller Timing Modes
Using the free running 16-bit internal timer, the CAN controller can be set in one of the two following timing modes:
• Timestamping Mode: The value of the internal timer is captured at each Start Of Frame or
each End Of Frame.
• Time Triggered Mode: The mailbox transfer operation is triggered when the internal timer
reaches the mailbox trigger.
Timestamping Mode is enabled by clearing the TTM bit in the CAN_MR register. Time Triggered Mode is enabled by setting the TTM bit in the CAN_MR register.
37.7.4.1
Timestamping Mode
Each mailbox has its own timestamp value. Each time a message is sent or received by a
mailbox, the 16-bit value MTIMESTAMP of the CAN_TIMESTP register is transferred to the
LSB bits of the CAN_MSRx register. The value read in the CAN_MSRx register corresponds
to the internal timer value at the Start Of Frame or the End Of Frame of the message handled
by the mailbox.
Figure 37-19. Mailbox Timestamp
Start of Frame
CAN BUS
End of Frame
Message 1
Message 2
CAN_TIM
TEOF
(CAN_MR)
TIMESTAMP
(CAN_TSTP)
Timestamp 1
MTIMESTAMP
(CAN_MSRx)
Timestamp 1
MTIMESTAMP
(CAN_MSRy)
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37.7.4.2
Time Triggered Mode
In Time Triggered Mode, basic cycles can be split into several time windows. A basic cycle
starts with a reference message. Each time a window is defined from the reference message,
a transmit operation should occur within a pre-defined time window. A mailbox must not win
the arbitration in a previous time window, and it must not be retried if the arbitration is lost in
the time window.
Figure 37-20. Time Triggered Principle
Time Cycle
Reference
Message
Reference
Message
Time Windows for Messages
Global Time
Time Trigger Mode is enabled by setting the TTM field in the CAN_MR register. In Time Triggered Mode, as in Timestamp Mode, the CAN_TIMESTP field captures the values of the
internal counter, but the MTIMESTAMP fields in the CAN_MSRx registers are not active and
are read at 0.
Synchronization by a Reference Message
In Time Triggered Mode, the internal timer counter is automatically reset when a new message is received in the last mailbox. This reset occurs after the reception of the End Of Frame
on the rising edge of the MRDY signal in the CAN_MSRx register. This allows synchronization
of the internal timer counter with the reception of a reference message and the start a new
time window.
Transmitting within a Time Window
A time mark is defined for each mailbox. It is defined in the 16-bit MTIMEMARK field of the
CAN_MMRx register. At each internal timer clock cycle, the value of the CAN_TIM is compared with each mailbox time mark. When the internal timer counter reaches the
MTIMEMARK value, an internal timer event for the mailbox is generated for the mailbox.
In Time Triggered Mode, transmit operations are delayed until the internal timer event for the
mailbox. The application prepares a message to be sent by setting the MTCR in the
CAN_MCRx register. The message is not sent until the CAN_TIM value is less than the
MTIMEMARK value defined in the CAN_MMRx register.
If the transmit operation is failed, i.e., the message loses the bus arbitration and the next transmit attempt is delayed until the next internal time trigger event. This prevents overlapping the
next time window, but the message is still pending and is retried in the next time window when
CAN_TIM value equals the MTIMEMARK value. It is also possible to prevent a retry by setting
the DRPT field in the CAN_MR register.
Freezing the Internal Timer Counter
The internal counter can be frozen by setting TIMFRZ in the CAN_MR register. This prevents
an unexpected roll-over when the counter reaches FFFFh. When this occurs, it automatically
freezes until a new reset is issued, either due to a message received in the last mailbox or any
other reset counter operations. The TOVF bit in the CAN_SR register is set when the counter
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is frozen. The TOVF bit in the CAN_SR register is cleared by reading the CAN_SR register.
Depending on the corresponding interrupt mask in the CAN_IMR register, an interrupt is generated when TOVF is set.
Figure 37-21. Time Triggered Operations
Message x
Arbitration Lost
End of Frame
CAN BUS
Reference
Message
Message y
Arbitration Win
Message y
Internal Counter Reset
CAN_TIM
Cleared by software
MRDY
(CAN_MSRlast_mailbox_number)
Timer Event x
MTIMEMARKx == CAN_TIM
MRDY
(CAN_MSRx)
MTIMEMARKy == CAN_TIM
Timer Event y
MRDY
(CAN_MSRy)
Time Window
Basic Cycle
Message x
Arbitration Win
End of Frame
CAN BUS
Reference
Message
Message x
Internal Counter Reset
CAN_TIM
Cleared by software
MRDY
(CAN_MSRlast_mailbox_number)
Timer Event x
MTIMEMARKx == CAN_TIM
MRDY
(CAN_MSRx)
Time Window
Basic Cycle
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37.8
Controller Area Network (CAN) User Interface
Table 37-2.
CAN Memory Map
Offset
Register
Name
Access
Reset State
0x0000
Mode Register
CAN_MR
Read-Write
0x0
0x0004
Interrupt Enable Register
CAN_IER
Write-only
-
0x0008
Interrupt Disable Register
CAN_IDR
Write-only
-
0x000C
Interrupt Mask Register
CAN_IMR
Read-only
0x0
0x0010
Status Register
CAN_SR
Read-only
0x0
0x0014
Baudrate Register
CAN_BR
Read/Write
0x0
0x0018
Timer Register
CAN_TIM
Read-only
0x0
0x001C
Timestamp Register
CAN_TIMESTP
Read-only
0x0
0x0020
Error Counter Register
CAN_ECR
Read-only
0x0
0x0024
Transfer Command Register
CAN_TCR
Write-only
-
0x0028
Abort Command Register
CAN_ACR
Write-only
-
–
–
–
0x0100 - 0x01FC
Reserved
0x0200
Mailbox 0 Mode Register
CAN_MMR0
Read/Write
0x0
0x0204
Mailbox 0 Acceptance Mask Register
CAN_MAM0
Read/Write
0x0
0x0208
Mailbox 0 ID Register
CAN_MID0
Read/Write
0x0
0x020C
Mailbox 0 Family ID Register
CAN_MFID0
Read-only
0x0
0x0210
Mailbox 0 Status Register
CAN_MSR0
Read-only
0x0
0x0214
Mailbox 0 Data Low Register
CAN_MDL0
Read/Write
0x0
0x0218
Mailbox 0 Data High Register
CAN_MDH0
Read/Write
0x0
0x021C
Mailbox 0 Control Register
CAN_MCR0
Write-only
-
0x0220
Mailbox 1 Mode Register
CAN_MMR1
Read/Write
0x0
0x0224
Mailbox 1 Acceptance Mask Register
CAN_MAM1
Read/Write
0x0
0x0228
Mailbox 1 ID register
CAN_MID1
Read/Write
0x0
0x022C
Mailbox 1 Family ID Register
CAN_MFID1
Read-only
0x0
0x0230
Mailbox 1 Status Register
CAN_MSR1
Read-only
0x0
0x0234
Mailbox 1 Data Low Register
CAN_MDL1
Read/Write
0x0
0x0238
Mailbox 1 Data High Register
CAN_MDH1
Read/Write
0x0
0x023C
Mailbox 1 Control Register
CAN_MCR1
Write-only
-
...
...
-
...
...
663
6249B–ATARM–14-Dec-06
37.8.1
CAN Mode Register
Name:
CAN_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
DRPT
6
TIMFRZ
5
TTM
4
TEOF
3
OVL
2
ABM
1
LPM
0
CANEN
• CANEN: CAN Controller Enable
0 = The CAN Controller is disabled.
1 = The CAN Controller is enabled.
• LPM: Disable/Enable Low Power Mode
0 = Disable Low Power Mode.
1 = Enable Low Power Mode.
CAN controller enters Low Power Mode once all pending messages have been transmitted.
• ABM: Disable/Enable Autobaud/Listen mode
0 = Disable Autobaud/listen mode.
1 = Enable Autobaud/listen mode.
• OVL: Disable/Enable Overload Frame
0 = No overload frame is generated.
1 = An overload frame is generated after each successful reception for mailboxes configured in Receive with/without overwrite Mode, Producer and Consumer.
• TEOF: Timestamp messages at each end of Frame
0 = The value of CAN_TIM is captured in the CAN_TIMESTP register at each Start Of Frame.
1 = The value of CAN_TIM is captured in the CAN_TIMESTP register at each End Of Frame.
• TTM: Disable/Enable Time Triggered Mode
0 = Time Triggered Mode is disabled.
1 = Time Triggered Mode is enabled.
• TIMFRZ: Enable Timer Freeze
0 = The internal timer continues to be incremented after it reached 0xFFFF.
1 = The internal timer stops incrementing after reaching 0xFFFF. It is restarted after a timer reset. See ”Freezing the Internal Timer Counter” on page 661.
• DRPT: Disable Repeat
0 = When a transmit mailbox loses the bus arbitration, the transfer request remains pending.
1 = When a transmit mailbox lose the bus arbitration, the transfer request is automatically aborted. It automatically raises
the MABT and MRDT flags in the corresponding CAN_MSRx.
664
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
37.8.2
CAN Interrupt Enable Register
Name:
CAN_IER
Access Type:
Write-only
31
–
30
–
29
–
28
BERR
27
FERR
26
AERR
25
SERR
24
CERR
23
TSTP
22
TOVF
21
WAKEUP
20
SLEEP
19
BOFF
18
ERRP
17
WARN
16
ERRA
15
MB15
14
MB14
13
MB13
12
MB12
11
MB11
10
MB10
9
MB9
8
MB8
7
MB7
6
MB6
5
MB5
4
MB4
3
MB3
2
MB2
1
MB1
0
MB0
• MBx: Mailbox x Interrupt Enable
0 = No effect.
1 = Enable Mailbox x interrupt.
• ERRA: Error Active mode Interrupt Enable
0 = No effect.
1 = Enable ERRA interrupt.
• WARN: Warning Limit Interrupt Enable
0 = No effect.
1 = Enable WARN interrupt.
• ERRP: Error Passive mode Interrupt Enable
0 = No effect.
1 = Enable ERRP interrupt.
• BOFF: Bus-off mode Interrupt Enable
0 = No effect.
1 = Enable BOFF interrupt.
• SLEEP: Sleep Interrupt Enable
0 = No effect.
1 = Enable SLEEP interrupt.
• WAKEUP: Wakeup Interrupt Enable
0 = No effect.
1 = Enable SLEEP interrupt.
• TOVF: Timer Overflow Interrupt Enable
0 = No effect.
1 = Enable TOVF interrupt.
• TSTP: TimeStamp Interrupt Enable
0 = No effect.
1 = Enable TSTP interrupt.
• CERR: CRC Error Interrupt Enable
0 = No effect.
1 = Enable CRC Error interrupt.
665
6249B–ATARM–14-Dec-06
• SERR: Stuffing Error Interrupt Enable
0 = No effect.
1 = Enable Stuffing Error interrupt.
• AERR: Acknowledgment Error Interrupt Enable
0 = No effect.
1 = Enable Acknowledgment Error interrupt.
• FERR: Form Error Interrupt Enable
0 = No effect.
1 = Enable Form Error interrupt.
• BERR: Bit Error Interrupt Enable
0 = No effect.
1 = Enable Bit Error interrupt.
666
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
37.8.3
CAN Interrupt Disable Register
Name:
CAN_IDR
Access Type:
Write-only
31
–
30
–
29
–
28
BERR
27
FERR
26
AERR
25
SERR
24
CERR
23
TSTP
22
TOVF
21
WAKEUP
20
SLEEP
19
BOFF
18
ERRP
17
WARN
16
ERRA
15
MB15
14
MB14
13
MB13
12
MB12
11
MB11
10
MB10
9
MB9
8
MB8
7
MB7
6
MB6
5
MB5
4
MB4
3
MB3
2
MB2
1
MB1
0
MB0
• MBx: Mailbox x Interrupt Disable
0 = No effect.
1 = Disable Mailbox x interrupt.
• ERRA: Error Active Mode Interrupt Disable
0 = No effect.
1 = Disable ERRA interrupt.
• WARN: Warning Limit Interrupt Disable
0 = No effect.
1 = Disable WARN interrupt.
• ERRP: Error Passive mode Interrupt Disable
0 = No effect.
1 = Disable ERRP interrupt.
• BOFF: Bus-off mode Interrupt Disable
0 = No effect.
1 = Disable BOFF interrupt.
• SLEEP: Sleep Interrupt Disable
0 = No effect.
1 = Disable SLEEP interrupt.
• WAKEUP: Wakeup Interrupt Disable
0 = No effect.
1 = Disable WAKEUP interrupt.
• TOVF: Timer Overflow Interrupt
0 = No effect.
1 = Disable TOVF interrupt.
• TSTP: TimeStamp Interrupt Disable
0 = No effect.
1 = Disable TSTP interrupt.
• CERR: CRC Error Interrupt Disable
0 = No effect.
1 = Disable CRC Error interrupt.
667
6249B–ATARM–14-Dec-06
• SERR: Stuffing Error Interrupt Disable
0 = No effect.
1 = Disable Stuffing Error interrupt.
• AERR: Acknowledgment Error Interrupt Disable
0 = No effect.
1 = Disable Acknowledgment Error interrupt.
• FERR: Form Error Interrupt Disable
0 = No effect.
1 = Disable Form Error interrupt.
• BERR: Bit Error Interrupt Disable
0 = No effect.
1 = Disable Bit Error interrupt.
668
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
37.8.4
CAN Interrupt Mask Register
Name:
CAN_IMR
Access Type:
Read-only
31
–
30
–
29
–
28
BERR
27
FERR
26
AERR
25
SERR
24
CERR
23
TSTP
22
TOVF
21
WAKEUP
20
SLEEP
19
BOFF
18
ERRP
17
WARN
16
ERRA
15
MB15
14
MB14
13
MB13
12
MB12
11
MB11
10
MB10
9
MB9
8
MB8
7
MB7
6
MB6
5
MB5
4
MB4
3
MB3
2
MB2
1
MB1
0
MB0
• MBx: Mailbox x Interrupt Mask
0 = Mailbox x interrupt is disabled.
1 = Mailbox x interrupt is enabled.
• ERRA: Error Active mode Interrupt Mask
0 = ERRA interrupt is disabled.
1 = ERRA interrupt is enabled.
• WARN: Warning Limit Interrupt Mask
0 = Warning Limit interrupt is disabled.
1 = Warning Limit interrupt is enabled.
• ERRP: Error Passive Mode Interrupt Mask
0 = ERRP interrupt is disabled.
1 = ERRP interrupt is enabled.
• BOFF: Bus-off Mode Interrupt Mask
0 = BOFF interrupt is disabled.
1 = BOFF interrupt is enabled.
• SLEEP: Sleep Interrupt Mask
0 = SLEEP interrupt is disabled.
1 = SLEEP interrupt is enabled.
• WAKEUP: Wakeup Interrupt Mask
0 = WAKEUP interrupt is disabled.
1 = WAKEUP interrupt is enabled.
• TOVF: Timer Overflow Interrupt Mask
0 = TOVF interrupt is disabled.
1 = TOVF interrupt is enabled.
• TSTP: Timestamp Interrupt Mask
0 = TSTP interrupt is disabled.
1 = TSTP interrupt is enabled.
• CERR: CRC Error Interrupt Mask
0 = CRC Error interrupt is disabled.
1 = CRC Error interrupt is enabled.
669
6249B–ATARM–14-Dec-06
• SERR: Stuffing Error Interrupt Mask
0 = Bit Stuffing Error interrupt is disabled.
1 = Bit Stuffing Error interrupt is enabled.
• AERR: Acknowledgment Error Interrupt Mask
0 = Acknowledgment Error interrupt is disabled.
1 = Acknowledgment Error interrupt is enabled.
• FERR: Form Error Interrupt Mask
0 = Form Error interrupt is disabled.
1 = Form Error interrupt is enabled.
• BERR: Bit Error Interrupt Mask
0 = Bit Error interrupt is disabled.
1 = Bit Error interrupt is enabled.
670
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
37.8.5
CAN Status Register
Name:
CAN_SR
Access Type:
Read-only
31
OVLSY
30
TBSY
29
RBSY
28
BERR
27
FERR
26
AERR
25
SERR
24
CERR
23
TSTP
22
TOVF
21
WAKEUP
20
SLEEP
19
BOFF
18
ERRP
17
WARN
16
ERRA
15
MB15
14
MB14
13
MB13
12
MB12
11
MB11
10
MB10
9
MB9
8
MB8
7
MB7
6
MB6
5
MB5
4
MB4
3
MB3
2
MB2
1
MB1
0
MB0
• MBx: Mailbox x Event
0 = No event occurred on Mailbox x.
1 = An event occurred on Mailbox x.
An event corresponds to MRDY, MABT fields in the CAN_MSRx register.
• ERRA: Error Active mode
0 = CAN controller is not in error active mode
1 = CAN controller is in error active mode
This flag is set depending on TEC and REC counter values. It is set when node is neither in error passive mode nor in bus
off mode.
This flag is automatically reset when above condition is not satisfied.
• WARN: Warning Limit
0 = CAN controller Warning Limit is not reached.
1 = CAN controller Warning Limit is reached.
This flag is set depending on TEC and REC counters values. It is set when at least one of the counters values exceeds 96.
This flag is automatically reset when above condition is not satisfied.
• ERRP: Error Passive mode
0 = CAN controller is not in error passive mode
1 = CAN controller is in error passive mode
This flag is set depending on TEC and REC counters values.
A node is error passive when TEC counter is greater or equal to 128 (decimal) or when the REC counter is greater or equal
to 128 (decimal) and less than 256.
This flag is automatically reset when above condition is not satisfied.
• BOFF: Bus Off mode
0 = CAN controller is not in bus-off mode
1 = CAN controller is in bus-off mode
This flag is set depending on TEC counter value. A node is bus off when TEC counter is greater or equal to 256 (decimal).
This flag is automatically reset when above condition is not satisfied.
• SLEEP: CAN controller in Low power Mode
0 = CAN controller is not in low power mode.
1 = CAN controller is in low power mode.
671
6249B–ATARM–14-Dec-06
This flag is automatically reset when Low power mode is disabled
• WAKEUP: CAN controller is not in Low power Mode
0 = CAN controller is in low power mode.
1 = CAN controller is not in low power mode.
When a WAKEUP event occurs, the CAN controller is synchronized with the bus activity. Messages can be transmitted or
received. The CAN controller clock must be available when a WAKEUP event occurs. This flag is automatically reset when
the CAN Controller enters Low Power mode.
• TOVF: Timer Overflow
0 = The timer has not rolled-over FFFFh to 0000h.
1 = The timer rolls-over FFFFh to 0000h.
This flag is automatically cleared by reading CAN_SR register.
• TSTP Timestamp
0 = No bus activity has been detected.
1 = A start of frame or an end of frame has been detected (according to the TEOF field in the CAN_MR register).
This flag is automatically cleared by reading the CAN_SR register.
• CERR: Mailbox CRC Error
0 = No CRC error occurred during a previous transfer.
1 = A CRC error occurred during a previous transfer.
A CRC error has been detected during last reception.
This flag is automatically cleared by reading CAN_SR register.
• SERR: Mailbox Stuffing Error
0 = No stuffing error occurred during a previous transfer.
1 = A stuffing error occurred during a previous transfer.
A form error results from the detection of more than five consecutive bit with the same polarity.
This flag is automatically cleared by reading CAN_SR register.
• AERR: Acknowledgment Error
0 = No acknowledgment error occurred during a previous transfer.
1 = An acknowledgment error occurred during a previous transfer.
An acknowledgment error is detected when no detection of the dominant bit in the acknowledge slot occurs.
This flag is automatically cleared by reading CAN_SR register.
• FERR: Form Error
0 = No form error occurred during a previous transfer
1 = A form error occurred during a previous transfer
A form error results from violations on one or more of the fixed form of the following bit fields:
– CRC delimiter
– ACK delimiter
– End of frame
– Error delimiter
– Overload delimiter
This flag is automatically cleared by reading CAN_SR register.
• BERR: Bit Error
0 = No bit error occurred during a previous transfer.
1 = A bit error occurred during a previous transfer.
672
AT91SAM9263 Preliminary
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AT91SAM9263 Preliminary
A bit error is set when the bit value monitored on the line is different from the bit value sent.
This flag is automatically cleared by reading CAN_SR register.
• RBSY: Receiver busy
0 = CAN receiver is not receiving a frame.
1 = CAN receiver is receiving a frame.
Receiver busy. This status bit is set by hardware while CAN receiver is acquiring or monitoring a frame (remote, data, overload or error frame). It is automatically reset when CAN is not receiving.
• TBSY: Transmitter busy
0 = CAN transmitter is not transmitting a frame.
1 = CAN transmitter is transmitting a frame.
Transmitter busy. This status bit is set by hardware while CAN transmitter is generating a frame (remote, data, overload or
error frame). It is automatically reset when CAN is not transmitting.
• OVLSY: Overload busy
0 = CAN transmitter is not transmitting an overload frame.
1 = CAN transmitter is transmitting a overload frame.
It is automatically reset when the bus is not transmitting an overload frame.
673
6249B–ATARM–14-Dec-06
37.8.6
CAN Baudrate Register
Name:
CAN_BR
Access Type:
Read/Write
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
SMP
23
–
22
21
20
19
BRP
18
17
16
15
–
14
–
13
12
11
–
10
9
PROPAG
8
7
–
6
5
PHASE1
4
3
–
2
1
PHASE2
0
SJW
Any modification on one of the fields of the CANBR register must be done while CAN module is disabled.
To compute the different Bit Timings, please refer to the Section 37.6.4.1 ”CAN Bit Timing Configuration” on page 642.
• PHASE2: Phase 2 segment
This phase is used to compensate the edge phase error.
t PHS2 = t CSC × ( PHASE2 + 1 )
Warning: PHASE2 value must be different from 0.
• PHASE1: Phase 1 segment
This phase is used to compensate for edge phase error.
t PHS1 = t CSC × ( PHASE1 + 1 )
• PROPAG: Programming time segment
This part of the bit time is used to compensate for the physical delay times within the network.
t PRS = t CSC × ( PROPAG + 1 )
• SJW: Re-synchronization jump width
To compensate for phase shifts between clock oscillators of different controllers on bus. The controller must re-synchronize
on any relevant signal edge of the current transmission. The synchronization jump width defines the maximum of clock
cycles a bit period may be shortened or lengthened by re-synchronization.
t SJW = t CSC × ( SJW + 1 )
• BRP: Baudrate Prescaler.
This field allows user to program the period of the CAN system clock to determine the individual bit timing.
t CSC = ( BRP + 1 ) ⁄ MCK
The BRP field must be within the range [1, 0x7F], i.e., BRP = 0 is not authorized.
• SMP: Sampling Mode
0 = The incoming bit stream is sampled once at sample point.
1 = The incoming bit stream is sampled three times with a period of a MCK clock period, centered on sample point.
SMP Sampling Mode is automatically disabled if BRP = 0.
674
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6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
37.8.7
CAN Timer Register
Name:
CAN_TIM
Access Type:
Read-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
TIMER15
14
TIMER14
13
TIMER13
12
TIMER12
11
TIMER11
10
TIMER10
9
TIMER9
8
TIMER8
7
TIMER7
6
TIMER6
5
TIMER5
4
TIMER4
3
TIMER3
2
TIMER2
1
TIMER1
0
TIMER0
• TIMERx: Timer
This field represents the internal CAN controller 16-bit timer value.
675
6249B–ATARM–14-Dec-06
37.8.8
CAN Timestamp Register
Name:
CAN_TIMESTP
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
MTIMESTAMP
15
MTIMESTAMP
14
MTIMESTAMP
13
MTIMESTAMP
12
MTIMESTAMP
11
MTIMESTAMP
10
MTIMESTAMP
9
MTIMESTAMP
8
7
6
5
4
3
2
1
0
MTIMESTAMP
7
MTIMESTAMP
6
MTIMESTAMP
5
MTIMESTAMP
4
MTIMESTAMP
3
MTIMESTAMP
2
MTIMESTAMP
1
MTIMESTAMP
0
• MTIMESTAMPx: Timestamp
This field represents the internal CAN controller 16-bit timer value.
If the TEOF bit is cleared in the CAN_MR register, the internal Timer Counter value is captured in the MTIMESTAMP field
at each start of frame. Else the value is captured at each end of frame. When the value is captured, the TSTP flag is set in
the CAN_SR register. If the TSTP mask in the CAN_IMR register is set, an interrupt is generated while TSTP flag is set in
the CAN_SR register. This flag is cleared by reading the CAN_SR register.
Note:
676
The CAN_TIMESTP register is reset when the CAN is disabled then enabled thanks to the CANEN bit in the CAN_MR.
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
37.8.9
CAN Error Counter Register
Name:
CAN_ECR
Access Type:
Read-only
31
–
30
–
29
–
28
–
23
22
21
20
27
–
26
–
25
–
24
–
19
18
17
16
TEC
15
–
14
–
13
–
12
–
11
–
10
–
9
–
8
–
7
6
5
4
3
2
1
0
REC
• REC: Receive Error Counter
When a receiver detects an error, REC will be increased by one, except when the detected error is a BIT ERROR while
sending an ACTIVE ERROR FLAG or an OVERLOAD FLAG.
When a receiver detects a dominant bit as the first bit after sending an ERROR FLAG, REC is increased by 8.
When a receiver detects a BIT ERROR while sending an ACTIVE ERROR FLAG, REC is increased by 8.
Any node tolerates up to 7 consecutive dominant bits after sending an ACTIVE ERROR FLAG, PASSIVE ERROR FLAG or
OVERLOAD FLAG. After detecting the 14th consecutive dominant bit (in case of an ACTIVE ERROR FLAG or an OVERLOAD FLAG) or after detecting the 8th consecutive dominant bit following a PASSIVE ERROR FLAG, and after each
sequence of additional eight consecutive dominant bits, each receiver increases its REC by 8.
After successful reception of a message, REC is decreased by 1 if it was between 1 and 127. If REC was 0, it stays 0, and
if it was greater than 127, then it is set to a value between 119 and 127.
• TEC: Transmit Error Counter
When a transmitter sends an ERROR FLAG, TEC is increased by 8 except when
– the transmitter is error passive and detects an ACKNOWLEDGMENT ERROR because of not detecting a
dominant ACK and does not detect a dominant bit while sending its PASSIVE ERROR FLAG.
– the transmitter sends an ERROR FLAG because a STUFF ERROR occurred during arbitration and should
have been recessive and has been sent as recessive but monitored as dominant.
When a transmitter detects a BIT ERROR while sending an ACTIVE ERROR FLAG or an OVERLOAD FLAG, the TEC will
be increased by 8.
Any node tolerates up to 7 consecutive dominant bits after sending an ACTIVE ERROR FLAG, PASSIVE ERROR FLAG or
OVERLOAD FLAG. After detecting the 14th consecutive dominant bit (in case of an ACTIVE ERROR FLAG or an OVERLOAD FLAG) or after detecting the 8th consecutive dominant bit following a PASSIVE ERROR FLAG, and after each
sequence of additional eight consecutive dominant bits every transmitter increases its TEC by 8.
After a successful transmission the TEC is decreased by 1 unless it was already 0.
677
6249B–ATARM–14-Dec-06
37.8.10
CAN Transfer Command Register
Name:
CAN_TCR
Access Type:
Write-only
31
TIMRST
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
MB15
14
MB14
13
MB13
12
MB12
11
MB11
10
MB10
9
MB9
8
MB8
7
MB7
6
MB6
5
MB5
4
MB4
3
MB3
2
MB2
1
MB1
0
MB0
This register initializes several transfer requests at the same time.
• MBx: Transfer Request for Mailbox x
Mailbox Object Type
Description
Receive
It receives the next message.
Receive with overwrite
This triggers a new reception.
Transmit
Sends data prepared in the mailbox as soon as possible.
Consumer
Sends a remote frame.
Producer
Sends data prepared in the mailbox after receiving a remote frame from a
consumer.
This flag clears the MRDY and MABT flags in the corresponding CAN_MSRx register.
When several mailboxes are requested to be transmitted simultaneously, they are transmitted in turn, starting with the mailbox with the highest priority. If several mailboxes have the same priority, then the mailbox with the lowest number is sent
first (i.e., MB0 will be transferred before MB1).
• TIMRST: Timer Reset
Resets the internal timer counter. If the internal timer counter is frozen, this command automatically re-enables it. This
command is useful in Time Triggered mode.
678
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AT91SAM9263 Preliminary
37.8.11
CAN Abort Command Register
Name:
CAN_ACR
Access Type:
Write-only
31
–
30
–
29
–
28
–
27
–
26
–
25
–
24
–
23
–
22
–
21
–
20
–
19
–
18
–
17
–
16
–
15
MB15
14
MB14
13
MB13
12
MB12
11
MB11
10
MB10
9
MB9
8
MB8
7
MB7
6
MB6
5
MB5
4
MB4
3
MB3
2
MB2
1
MB1
0
MB0
This register initializes several abort requests at the same time.
• MBx: Abort Request for Mailbox x
Mailbox Object Type
Description
Receive
No action
Receive with overwrite
No action
Transmit
Cancels transfer request if the message has not been transmitted to the
CAN transceiver.
Consumer
Cancels the current transfer before the remote frame has been sent.
Producer
Cancels the current transfer. The next remote frame is not serviced.
It is possible to set MACR field (in the CAN_MCRx register) for each mailbox.
679
6249B–ATARM–14-Dec-06
37.8.12
CAN Message Mode Register
Name:
CAN_MMRx
Access Type:
Read/Write
31
–
30
–
29
–
28
–
27
–
26
23
–
22
–
21
–
20
–
19
18
25
24
MOT
17
16
PRIOR
15
14
13
12
11
10
9
8
MTIMEMARK1
5
MTIMEMARK1
4
MTIMEMARK1
3
MTIMEMARK1
2
MTIMEMARK1
1
MTIMEMARK1
0
MTIMEMARK9
MTIMEMARK8
7
6
5
4
3
2
1
0
MTIMEMARK7
MTIMEMARK6
MTIMEMARK5
MTIMEMARK4
MTIMEMARK3
MTIMEMARK2
MTIMEMARK1
MTIMEMARK0
• MTIMEMARK: Mailbox Timemark
This field is active in Time Triggered Mode. Transmit operations are allowed when the internal timer counter reaches the
Mailbox Timemark. See ”Transmitting within a Time Window” on page 661.
In Timestamp Mode, MTIMEMARK is set to 0.
• PRIOR: Mailbox Priority
This field has no effect in receive and receive with overwrite modes. In these modes, the mailbox with the lowest number is
serviced first.
When several mailboxes try to transmit a message at the same time, the mailbox with the highest priority is serviced first. If
several mailboxes have the same priority, the mailbox with the lowest number is serviced first (i.e., MBx0 is serviced before
MBx 15 if they have the same priority).
• MOT: Mailbox Object Type
This field allows the user to define the type of the mailbox. All mailboxes are independently configurable. Five different
types are possible for each mailbox:
MOT
680
Mailbox Object Type
0
0
0
Mailbox is disabled. This prevents receiving or transmitting any messages
with this mailbox.
0
0
1
Reception Mailbox. Mailbox is configured for reception. If a message is
received while the mailbox data register is full, it is discarded.
0
1
0
Reception mailbox with overwrite. Mailbox is configured for reception. If a
message is received while the mailbox is full, it overwrites the previous
message.
0
1
1
Transmit mailbox. Mailbox is configured for transmission.
1
0
0
Consumer Mailbox. Mailbox is configured in reception but behaves as a
Transmit Mailbox, i.e., it sends a remote frame and waits for an answer.
1
0
1
Producer Mailbox. Mailbox is configured in transmission but also behaves
like a reception mailbox, i.e., it waits to receive a Remote Frame before
sending its contents.
1
1
X
Reserved
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37.8.13
CAN Message Acceptance Mask Register
Name:
CAN_MAMx
Access Type:
Read/Write
31
–
30
–
29
MIDE
23
22
21
28
27
26
MIDvA
25
20
19
18
17
MIDvA
15
14
13
24
16
MIDvB
12
11
10
9
8
3
2
1
0
MIDvB
7
6
5
4
MIDvB
To prevent concurrent access with the internal CAN core, the application must disable the mailbox before writing to
CAN_MAMx registers.
• MIDvB: Complementary bits for identifier in extended frame mode
Acceptance mask for corresponding field of the message IDvB register of the mailbox.
• MIDvA: Identifier for standard frame mode
Acceptance mask for corresponding field of the message IDvA register of the mailbox.
• MIDE: Identifier Version
0= Compares IDvA from the received frame with the CAN_MIDx register masked with CAN_MAMx register.
1= Compares IDvA and IDvB from the received frame with the CAN_MIDx register masked with CAN_MAMx register.
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37.8.14
CAN Message ID Register
Name:
CAN_MIDx
Access Type:
Read/Write
31
–
30
–
29
MIDE
23
22
21
28
27
26
MIDvA
25
20
19
18
17
MIDvA
15
14
13
24
16
MIDvB
12
11
10
9
8
3
2
1
0
MIDvB
7
6
5
4
MIDvB
To prevent concurrent access with the internal CAN core, the application must disable the mailbox before writing to
CAN_MIDx registers.
• MIDvB: Complementary bits for identifier in extended frame mode
If MIDE is cleared, MIDvB value is 0.
• MIDE: Identifier Version
This bit allows the user to define the version of messages processed by the mailbox. If set, mailbox is dealing with version
2.0 Part B messages; otherwise, mailbox is dealing with version 2.0 Part A messages.
• MIDvA: Identifier for standard frame mode
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37.8.15
CAN Message Family ID Register
Name:
CAN_MFIDx
Access Type:
Read-only
31
–
30
–
29
–
28
23
22
21
20
27
26
MFID
25
24
19
18
17
16
11
10
9
8
3
2
1
0
MFID
15
14
13
12
MFID
7
6
5
4
MFID
• MFID: Family ID
This field contains the concatenation of CAN_MIDx register bits masked by the CAN_MAMx register. This field is useful to
speed up message ID decoding. The message acceptance procedure is described below.
As an example:
CAN_MIDx = 0x305A4321
CAN_MAMx = 0x3FF0F0FF
CAN_MFIDx = 0x000000A3
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37.8.16
CAN Message Status Register
Name:
CAN_MSRx
Access Type:
Read only
31
–
30
–
29
–
28
–
27
–
26
–
23
MRDY
22
MABT
21
–
20
MRTR
19
18
25
–
24
MMI
17
16
MDLC
15
14
13
12
11
10
9
8
MTIMESTAMP
15
MTIMESTAMP
14
MTIMESTAMP
13
MTIMESTAMP
12
MTIMESTAMP
11
MTIMESTAMP
10
MTIMESTAMP
9
MTIMESTAMP
8
7
6
5
4
3
2
1
0
MTIMESTAMP
7
MTIMESTAMP
6
MTIMESTAMP
5
MTIMESTAMP
4
MTIMESTAMP
3
MTIMESTAMP
2
MTIMESTAMP
1
MTIMESTAMP
0
These register fields are updated each time a message transfer is received or aborted.
MMI is cleared by reading the CAN_MSRx register.
MRDY, MABT are cleared by writing MTCR or MACR in the CAN_MCRx register.
Warning: MRTR and MDLC state depends partly on the mailbox object type.
• MTIMESTAMP: Timer value
This field is updated only when time-triggered operations are disabled (TTM cleared in CAN_MR register). If the TEOF field
in the CAN_MR register is cleared, TIMESTAMP is the internal timer value at the start of frame of the last message
received or sent by the mailbox. If the TEOF field in the CAN_MR register is set, TIMESTAMP is the internal timer value at
the end of frame of the last message received or sent by the mailbox.
In Time Triggered Mode, MTIMESTAMP is set to 0.
• MDLC: Mailbox Data Length Code
Mailbox Object Type
Description
Receive
Length of the first mailbox message received
Receive with overwrite
Length of the last mailbox message received
Transmit
No action
Consumer
Length of the mailbox message received
Producer
Length of the mailbox message to be sent after the remote frame reception
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• MRTR: Mailbox Remote Transmission Request
Mailbox Object Type
Description
Receive
The first frame received has the RTR bit set.
Receive with overwrite
The last frame received has the RTR bit set.
Transmit
Reserved
Consumer
Reserved. After setting the MOT field in the CAN_MMR, MRTR is reset to 1.
Producer
Reserved. After setting the MOT field in the CAN_MMR, MRTR is reset to 0.
• MABT: Mailbox Message Abort
An interrupt is triggered when MABT is set.
0 = Previous transfer is not aborted.
1 = Previous transfer has been aborted.
This flag is cleared by writing to CAN_MCRx register
Mailbox Object Type
Description
Receive
Reserved
Receive with overwrite
Reserved
Transmit
Previous transfer has been aborted
Consumer
The remote frame transfer request has been aborted.
Producer
The response to the remote frame transfer has been aborted.
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• MRDY: Mailbox Ready
An interrupt is triggered when MRDY is set.
0 = Mailbox data registers can not be read/written by the software application. CAN_MDx are locked by the CAN_MDx.
1 = Mailbox data registers can be read/written by the software application.
This flag is cleared by writing to CAN_MCRx register.
Mailbox Object Type
Description
Receive
At least one message has been received since the last mailbox transfer order. Data from the first frame
received can be read in the CAN_MDxx registers.
After setting the MOT field in the CAN_MMR, MRDY is reset to 0.
Receive with overwrite
At least one frame has been received since the last mailbox transfer order. Data from the last frame received
can be read in the CAN_MDxx registers.
After setting the MOT field in the CAN_MMR, MRDY is reset to 0.
Transmit
Mailbox data have been transmitted.
After setting the MOT field in the CAN_MMR, MRDY is reset to 1.
Consumer
At least one message has been received since the last mailbox transfer order. Data from the first message
received can be read in the CAN_MDxx registers.
After setting the MOT field in the CAN_MMR, MRDY is reset to 0.
Producer
A remote frame has been received, mailbox data have been transmitted.
After setting the MOT field in the CAN_MMR, MRDY is reset to 1.
• MMI: Mailbox Message Ignored
0 = No message has been ignored during the previous transfer
1 = At least one message has been ignored during the previous transfer
Cleared by reading the CAN_MSRx register.
Mailbox Object Type
Description
Receive
Set when at least two messages intended for the mailbox have been sent. The first one is available in the
mailbox data register. Others have been ignored. A mailbox with a lower priority may have accepted the
message.
Receive with overwrite
Set when at least two messages intended for the mailbox have been sent. The last one is available in the
mailbox data register. Previous ones have been lost.
Transmit
Reserved
Consumer
A remote frame has been sent by the mailbox but several messages have been received. The first one is
available in the mailbox data register. Others have been ignored. Another mailbox with a lower priority may
have accepted the message.
Producer
A remote frame has been received, but no data are available to be sent.
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37.8.17
CAN Message Data Low Register
Name:
CAN_MDLx
Access Type:
Read/Write
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
MDL
23
22
21
20
MDL
15
14
13
12
MDL
7
6
5
4
MDL
• MDL: Message Data Low Value
When MRDY field is set in the CAN_MSRx register, the lower 32 bits of a received message can be read or written by the
software application. Otherwise, the MDL value is locked by the CAN controller to send/receive a new message.
In Receive with overwrite, the CAN controller may modify MDL value while the software application reads MDH and MDL
registers. To check that MDH and MDL do not belong to different messages, the application has to check the MMI field in
the CAN_MSRx register. In this mode, the software application must re-read CAN_MDH and CAN_MDL, while the MMI bit
in the CAN_MSRx register is set.
Bytes are received/sent on the bus in the following order:
1. CAN_MDL[7:0]
2. CAN_MDL[15:8]
3. CAN_MDL[23:16]
4. CAN_MDL[31:24]
5. CAN_MDH[7:0]
6. CAN_MDH[15:8]
7. CAN_MDH[23:16]
8. CAN_MDH[31:24]
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37.8.18
CAN Message Data High Register
Name:
CAN_MDHx
Access Type:
Read/Write
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
MDH
23
22
21
20
MDH
15
14
13
12
MDH
7
6
5
4
MDH
• MDH: Message Data High Value
When MRDY field is set in the CAN_MSRx register, the upper 32 bits of a received message are read or written by the software application. Otherwise, the MDH value is locked by the CAN controller to send/receive a new message.
In Receive with overwrite, the CAN controller may modify MDH value while the software application reads MDH and MDL
registers. To check that MDH and MDL do not belong to different messages, the application has to check the MMI field in
the CAN_MSRx register. In this mode, the software application must re-read CAN_MDH and CAN_MDL, while the MMI bit
in the CAN_MSRx register is set.
Bytes are received/sent on the bus in the following order:
1. CAN_MDL[7:0]
2. CAN_MDL[15:8]
3. CAN_MDL[23:16]
4. CAN_MDL[31:24]
5. CAN_MDH[7:0]
6. CAN_MDH[15:8]
7. CAN_MDH[23:16]
8. CAN_MDH[31:24]
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37.8.19
CAN Message Control Register
Name:
CAN_MCRx
Access Type:
Write-only
31
–
30
–
29
–
28
–
27
–
26
–
23
MTCR
22
MACR
21
–
20
MRTR
19
18
15
–
14
13
–
12
11
–
7
–
6
5
–
4
3
–
–
–
–
–
25
24
–
–
17
16
10
9
–
–
8
–
2
–
1
0
–
–
MDLC
• MDLC: Mailbox Data Length Code
Mailbox Object Type
Description
Receive
No action.
Receive with overwrite
No action.
Transmit
Length of the mailbox message.
Consumer
No action.
Producer
Length of the mailbox message to be sent after the remote frame reception.
• MRTR: Mailbox Remote Transmission Request
Mailbox Object Type
Description
Receive
No action
Receive with overwrite
No action
Transmit
Set the RTR bit in the sent frame
Consumer
No action, the RTR bit in the sent frame is set automatically
Producer
No action
Consumer situations can be handled automatically by setting the mailbox object type in Consumer. This requires only one
mailbox.
It can also be handled using two mailboxes, one in reception, the other in transmission. The MRTR and the MTCR bits
must be set in the same time.
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• MACR: Abort Request for Mailbox x
Mailbox Object Type
Description
Receive
No action
Receive with overwrite
No action
Transmit
Cancels transfer request if the message has not been transmitted to the
CAN transceiver.
Consumer
Cancels the current transfer before the remote frame has been sent.
Producer
Cancels the current transfer. The next remote frame will not be serviced.
It is possible to set MACR field for several mailboxes in the same time, setting several bits to the CAN_ACR register.
• MTCR: Mailbox Transfer Command
Mailbox Object Type
Receive
Receive with overwrite
Transmit
Description
Allows the reception of the next message.
Triggers a new reception.
Sends data prepared in the mailbox as soon as possible.
Consumer
Sends a remote transmission frame.
Producer
Sends data prepared in the mailbox after receiving a remote frame from a
Consumer.
This flag clears the MRDY and MABT flags in the CAN_MSRx register.
When several mailboxes are requested to be transmitted simultaneously, they are transmitted in turn. The mailbox with the
highest priority is serviced first. If several mailboxes have the same priority, the mailbox with the lowest number is serviced
first (i.e., MBx0 will be serviced before MBx 15 if they have the same priority).
It is possible to set MTCR for several mailboxes at the same time by writing to the CAN_TCR register.
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38. Pulse Width Modulation (PWM) Controller
38.1
Description
The PWM macrocell controls several channels independently. Each channel controls one
square output waveform. Characteristics of the output waveform such as period, duty-cycle
and polarity are configurable through the user interface. Each channel selects and uses one of
the clocks provided by the clock generator. The clock generator provides several clocks resulting from the division of the PWM macrocell master clock.
All PWM macrocell accesses are made through APB mapped registers.
Channels can be synchronized, to generate non overlapped waveforms. All channels integrate
a double buffering system in order to prevent an unexpected output waveform while modifying
the period or the duty-cycle.
38.2
Block Diagram
Figure 38-1. Pulse Width Modulation Controller Block Diagram
PWM
Controller
PWMx
Channel
Period
PWMx
Update
Duty Cycle
Clock
Selector
Comparator
PWMx
Counter
PIO
PWM0
Channel
Period
PWM0
Update
Duty Cycle
Clock
Selector
PMC
MCK
Clock Generator
Comparator
PWM0
Counter
APB Interface
Interrupt Generator
AIC
APB
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38.3
I/O Lines Description
Each channel outputs one waveform on one external I/O line.
Table 38-1.
38.4
38.4.1
I/O Line Description
Name
Description
Type
PWMx
PWM Waveform Output for channel x
Output
Product Dependencies
I/O Lines
The pins used for interfacing the PWM may be multiplexed with PIO lines. The programmer
must first program the PIO controller to assign the desired PWM pins to their peripheral function. If I/O lines of the PWM are not used by the application, they can be used for other
purposes by the PIO controller.
All of the PWM outputs may or may not be enabled. If an application requires only four channels, then only four PIO lines will be assigned to PWM outputs.
38.4.2
Power Management
The PWM is not continuously clocked. The programmer must first enable the PWM clock in
the Power Management Controller (PMC) before using the PWM. However, if the application
does not require PWM operations, the PWM clock can be stopped when not needed and be
restarted later. In this case, the PWM will resume its operations where it left off.
Configuring the PWM does not require the PWM clock to be enabled.
38.4.3
38.5
Interrupt Sources
The PWM interrupt line is connected on one of the internal sources of the Advanced Interrupt
Controller. Using the PWM interrupt requires the AIC to be programmed first. Note that it is not
recommended to use the PWM interrupt line in edge sensitive mode.
Functional Description
The PWM macrocell is primarily composed of a clock generator module and X channels.
– Clocked by the system clock, MCK, the clock generator module provides 13
clocks.
– Each channel can independently choose one of the clock generator outputs.
– Each channel generates an output waveform with attributes that can be defined
independently for each channel through the user interface registers.
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38.5.1
PWM Clock Generator
Figure 38-2. Functional View of the Clock Generator Block Diagram
MCK
modulo n counter
MCK
MCK/2
MCK/4
MCK/8
MCK/16
MCK/32
MCK/64
MCK/128
MCK/256
MCK/512
MCK/1024
Divider A
PREA
clkA
DIVA
PWM_MR
Divider B
PREB
clkB
DIVB
PWM_MR
Caution: Before using the PWM macrocell, the programmer must first enable the PWM clock
in the Power Management Controller (PMC).
The PWM macrocell master clock, MCK, is divided in the clock generator module to provide
different clocks available for all channels. Each channel can independently select one of the
divided clocks.
The clock generator is divided in three blocks:
– a modulo n counter which provides 11 clocks: FMCK, FMCK/2, FMCK/4, FMCK/8,
FMCK/16, FMCK/32, FMCK/64, FMCK/128, FMCK/256, FMCK/512, FMCK/1024
– two linear dividers (1, 1/2, 1/3, ... 1/255) that provide two separate clocks: clkA and
clkB
Each linear divider can independently divide one of the clocks of the modulo n counter. The
selection of the clock to be divided is made according to the PREA (PREB) field of the PWM
Mode register (PWM_MR). The resulting clock clkA (clkB) is the clock selected divided by
DIVA (DIVB) field value in the PWM Mode register (PWM_MR).
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After a reset of the PWM controller, DIVA (DIVB) and PREA (PREB) in the PWM Mode register are set to 0. This implies that after reset clkA (clkB) are turned off.
At reset, all clocks provided by the modulo n counter are turned off except clock “clk”. This situation is also true when the PWM master clock is turned off through the Power Management
Controller.
38.5.2
38.5.2.1
PWM Channel
Block Diagram
Figure 38-3. Functional View of the Channel Block Diagram
inputs
from clock
generator
Channel
Clock
Selector
Internal
Counter
Comparator
PWMx output waveform
inputs from
APB bus
Each of the X channels is composed of three blocks:
• A clock selector which selects one of the clocks provided by the clock generator described
in Section 38.5.1 ”PWM Clock Generator” on page 693.
• An internal counter clocked by the output of the clock selector. This internal counter is
incremented or decremented according to the channel configuration and comparators
events. The size of the internal counter is Y bits.
• A comparator used to generate events according to the internal counter value. It also
computes the PWMx output waveform according to the configuration.
38.5.2.2
Waveform Properties
The different properties of output waveforms are:
• the internal clock selection. The internal channel counter is clocked by one of the clocks
provided by the clock generator described in the previous section. This channel parameter
is defined in the CPRE field of the PWM_CMRx register. This field is reset at 0.
• the waveform period. This channel parameter is defined in the CPRD field of the
PWM_CPRDx register.
- If the waveform is left aligned, then the output waveform period depends on the counter
source clock and can be calculated:
By using the Master Clock (MCK) divided by an X given prescaler value
(with X being 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, or 1024), the resulting period formula
will be:
(------------------------------X × CPRD )MCK
By using a Master Clock divided by one of both DIVA or DIVB divider, the formula
becomes, respectively:
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(-----------------------------------------CRPD × DIVA )( CRPD × DIVAB )
or ----------------------------------------------MCK
MCK
If the waveform is center aligned then the output waveform period depends on the counter
source clock and can be calculated:
By using the Master Clock (MCK) divided by an X given prescaler value
(with X being 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, or 1024). The resulting period formula
will be:
(-----------------------------------------2 × X × CPRD )MCK
By using a Master Clock divided by one of both DIVA or DIVB divider, the formula
becomes, respectively:
(----------------------------------------------------2 × CPRD × DIVA )( 2 × CPRD × DIVB )
or -----------------------------------------------------MCK
MCK
• the waveform duty cycle. This channel parameter is defined in the CDTY field of the
PWM_CDTYx register.
If the waveform is left aligned then:
period – 1 ⁄ fchannel_x_clock × CDTY )duty cycle = (----------------------------------------------------------------------------------------------------------period
If the waveform is center aligned, then:
( period ⁄ 2 ) – 1 ⁄ fchannel_x_clock × CDTY ) )duty cycle = (----------------------------------------------------------------------------------------------------------------------------( period ⁄ 2 )
• the waveform polarity. At the beginning of the period, the signal can be at high or low
level. This property is defined in the CPOL field of the PWM_CMRx register. By default the
signal starts by a low level.
• the waveform alignment. The output waveform can be left or center aligned. Center
aligned waveforms can be used to generate non overlapped waveforms. This property is
defined in the CALG field of the PWM_CMRx register. The default mode is left aligned.
Figure 38-4. Non Overlapped Center Aligned Waveforms
No overlap
PWM0
PWM1
Period
Note:
1. See Figure 38-5 on page 697 for a detailed description of center aligned waveforms.
When center aligned, the internal channel counter increases up to CPRD and.decreases down
to 0. This ends the period.
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When left aligned, the internal channel counter increases up to CPRD and is reset. This ends
the period.
Thus, for the same CPRD value, the period for a center aligned channel is twice the period for
a left aligned channel.
Waveforms are fixed at 0 when:
• CDTY = CPRD and CPOL = 0
• CDTY = 0 and CPOL = 1
Waveforms are fixed at 1 (once the channel is enabled) when:
• CDTY = 0 and CPOL = 0
• CDTY = CPRD and CPOL = 1
The waveform polarity must be set before enabling the channel. This immediately affects the
channel output level. Changes on channel polarity are not taken into account while the channel is enabled.
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Figure 38-5. Waveform Properties
PWM_MCKx
CHIDx(PWM_SR)
CHIDx(PWM_ENA)
CHIDx(PWM_DIS)
Center Aligned
CALG(PWM_CMRx) = 1
PWM_CCNTx
CPRD(PWM_CPRDx)
CDTY(PWM_CDTYx)
Period
Output Waveform PWMx
CPOL(PWM_CMRx) = 0
Output Waveform PWMx
CPOL(PWM_CMRx) = 1
CHIDx(PWM_ISR)
Left Aligned
CALG(PWM_CMRx) = 0
PWM_CCNTx
CPRD(PWM_CPRDx)
CDTY(PWM_CDTYx)
Period
Output Waveform PWMx
CPOL(PWM_CMRx) = 0
Output Waveform PWMx
CPOL(PWM_CMRx) = 1
CHIDx(PWM_ISR)
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38.5.3
38.5.3.1
PWM Controller Operations
Initialization
Before enabling the output channel, this channel must have been configured by the software
application:
• Configuration of the clock generator if DIVA and DIVB are required
• Selection of the clock for each channel (CPRE field in the PWM_CMRx register)
• Configuration of the waveform alignment for each channel (CALG field in the PWM_CMRx
register)
• Configuration of the period for each channel (CPRD in the PWM_CPRDx register). Writing
in PWM_CPRDx Register is possible while the channel is disabled. After validation of the
channel, the user must use PWM_CUPDx Register to update PWM_CPRDx as explained
below.
• Configuration of the duty cycle for each channel (CDTY in the PWM_CDTYx register).
Writing in PWM_CDTYx Register is possible while the channel is disabled. After validation
of the channel, the user must use PWM_CUPDx Register to update PWM_CDTYx as
explained below.
• Configuration of the output waveform polarity for each channel (CPOL in the PWM_CMRx
register)
• Enable Interrupts (Writing CHIDx in the PWM_IER register)
• Enable the PWM channel (Writing CHIDx in the PWM_ENA register)
It is possible to synchronize different channels by enabling them at the same time by means of
writing simultaneously several CHIDx bits in the PWM_ENA register.
• In such a situation, all channels may have the same clock selector configuration and the
same period specified.
38.5.3.2
Source Clock Selection Criteria
The large number of source clocks can make selection difficult. The relationship between the
value in the Period Register (PWM_CPRDx) and the Duty Cycle Register (PWM_CDTYx) can
help the user in choosing. The event number written in the Period Register gives the PWM
accuracy. The Duty Cycle quantum cannot be lower than 1/PWM_CPRDx value. The higher
the value of PWM_CPRDx, the greater the PWM accuracy.
For example, if the user sets 15 (in decimal) in PWM_CPRDx, the user is able to set a value
between 1 up to 14 in PWM_CDTYx Register. The resulting duty cycle quantum cannot be
lower than 1/15 of the PWM period.
38.5.3.3
Changing the Duty Cycle or the Period
It is possible to modulate the output waveform duty cycle or period.
To prevent unexpected output waveform, the user must use the update register
(PWM_CUPDx) to change waveform parameters while the channel is still enabled. The user
can write a new period value or duty cycle value in the update register (PWM_CUPDx). This
register holds the new value until the end of the current cycle and updates the value for the
next cycle. Depending on the CPD field in the PWM_CMRx register, PWM_CUPDx either
updates PWM_CPRDx or PWM_CDTYx. Note that even if the update register is used, the
period must not be smaller than the duty cycle.
698
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AT91SAM9263 Preliminary
Figure 38-6. Synchronized Period or Duty Cycle Update
User's Writing
PWM_CUPDx Value
0
1
PWM_CPRDx
PWM_CMRx. CPD
PWM_CDTYx
End of Cycle
To prevent overwriting the PWM_CUPDx by software, the user can use status events in order
to synchronize his software. Two methods are possible. In both, the user must enable the dedicated interrupt in PWM_IER at PWM Controller level.
The first method (polling method) consists of reading the relevant status bit in PWM_ISR Register according to the enabled channel(s). See Figure 38-7.
The second method uses an Interrupt Service Routine associated with the PWM channel.
Note:
Reading the PWM_ISR register automatically clears CHIDx flags.
Figure 38-7. Polling Method
PWM_ISR Read
Acknowledgement and clear previous register state
Writing in CPD field
Update of the Period or Duty Cycle
CHIDx = 1
YES
Writing in PWM_CUPDx
The last write has been taken into account
Note:
Polarity and alignment can be modified only when the channel is disabled.
699
6249B–ATARM–14-Dec-06
38.5.3.4
Interrupts
Depending on the interrupt mask in the PWM_IMR register, an interrupt is generated at the
end of the corresponding channel period. The interrupt remains active until a read operation in
the PWM_ISR register occurs.
A channel interrupt is enabled by setting the corresponding bit in the PWM_IER register. A
channel interrupt is disabled by setting the corresponding bit in the PWM_IDR register.
38.6
Pulse Width Modulation (PWM) Controller User Interface
Table 38-2.
PWM Controller Registers
Access
Peripheral
Reset Value
PWM_MR
Read/Write
0
PWM Enable Register
PWM_ENA
Write-only
-
0x08
PWM Disable Register
PWM_DIS
Write-only
-
0x0C
PWM Status Register
PWM_SR
Read-only
0
0x10
PWM Interrupt Enable Register
PWM_IER
Write-only
-
0x14
PWM Interrupt Disable Register
PWM_IDR
Write-only
-
0x18
PWM Interrupt Mask Register
PWM_IMR
Read-only
0
0x1C
PWM Interrupt Status Register
PWM_ISR
Read-only
0
0x4C - 0xFC
Reserved
–
–
0x100 - 0x1FC
Reserved
0x200
Channel 0 Mode Register
PWM_CMR0
Read/Write
0x0
0x204
Channel 0 Duty Cycle Register
PWM_CDTY0
Read/Write
0x0
0x208
Channel 0 Period Register
PWM_CPRD0
Read/Write
0x0
0x20C
Channel 0 Counter Register
PWM_CCNT0
Read-only
0x0
0x210
Channel 0 Update Register
PWM_CUPD0
Write-only
-
...
Reserved
0x220
Channel 1 Mode Register
PWM_CMR1
Read/Write
0x0
0x224
Channel 1 Duty Cycle Register
PWM_CDTY1
Read/Write
0x0
0x228
Channel 1 Period Register
PWM_CPRD1
Read/Write
0x0
0x22C
Channel 1 Counter Register
PWM_CCNT1
Read-only
0x0
0x230
Channel 1 Update Register
PWM_CUPD1
Write-only
-
...
...
...
...
...
Offset
Register
Name
0x00
PWM Mode Register
0x04
700
–
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
38.6.1
PWM Mode Register
Register Name:
PWM_MR
Access Type:
Read/Write
31
–
30
–
29
–
28
–
23
22
21
20
27
26
25
24
17
16
9
8
1
0
PREB
19
18
10
DIVB
15
–
14
–
13
–
12
–
11
7
6
5
4
3
PREA
2
DIVA
• DIVA, DIVB: CLKA, CLKB Divide Factor
DIVA, DIVB
CLKA, CLKB
0
CLKA, CLKB clock is turned off
1
CLKA, CLKB clock is clock selected by PREA, PREB
2-255
CLKA, CLKB clock is clock selected by PREA, PREB divided by DIVA, DIVB factor.
• PREA, PREB
Table 38-3.
PREA, PREB
Divider Input Clock
0
0
0
0
MCK.
0
0
0
1
MCK/2
0
0
1
0
MCK/4
0
0
1
1
MCK/8
0
1
0
0
MCK/16
0
1
0
1
MCK/32
0
1
1
0
MCK/64
0
1
1
1
MCK/128
1
0
0
0
MCK/256
1
0
0
1
MCK/512
1
0
1
0
MCK/1024
Other
Reserved
701
6249B–ATARM–14-Dec-06
38.6.2
PWM Enable Register
Register Name:
PWM_ENA
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
CHID3
2
CHID2
1
CHID1
0
CHID0
• CHIDx: Channel ID
0 = No effect.
1 = Enable PWM output for channel x.
38.6.3
PWM Disable Register
Register Name:
PWM_DIS
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
CHID3
2
CHID2
1
CHID1
0
CHID0
• CHIDx: Channel ID
0 = No effect.
1 = Disable PWM output for channel x.
702
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
38.6.4
PWM Status Register
Register Name:
PWM_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
CHID3
2
CHID2
1
CHID1
0
CHID0
• CHIDx: Channel ID
0 = PWM output for channel x is disabled.
1 = PWM output for channel x is enabled.
703
6249B–ATARM–14-Dec-06
38.6.5
PWM Interrupt Enable Register
Register Name:
PWM_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
CHID3
2
CHID2
1
CHID1
0
CHID0
• CHIDx: Channel ID.
0 = No effect.
1 = Enable interrupt for PWM channel x.
38.6.6
PWM Interrupt Disable Register
Register Name:
PWM_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
CHID3
2
CHID2
1
CHID1
0
CHID0
• CHIDx: Channel ID.
0 = No effect.
1 = Disable interrupt for PWM channel x.
704
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
38.6.7
PWM Interrupt Mask Register
Register Name:
PWM_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
CHID3
2
CHID2
1
CHID1
0
CHID0
• CHIDx: Channel ID.
0 = Interrupt for PWM channel x is disabled.
1 = Interrupt for PWM channel x is enabled.
38.6.8
PWM Interrupt Status Register
Register Name:
PWM_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
CHID3
2
CHID2
1
CHID1
0
CHID0
• CHIDx: Channel ID
0 = No new channel period has been achieved since the last read of the PWM_ISR register.
1 = At least one new channel period has been achieved since the last read of the PWM_ISR register.
Note: Reading PWM_ISR automatically clears CHIDx flags.
705
6249B–ATARM–14-Dec-06
38.6.9
PWM Channel Mode Register
Register Name:
PWM_CMRx
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
CPD
9
CPOL
8
CALG
7
–
6
–
5
–
4
–
3
2
1
0
CPRE
• CPRE: Channel Pre-scaler
Table 38-4.
CPRE
Channel Pre-scaler
0
0
0
0
MCK
0
0
0
1
MCK/2
0
0
1
0
MCK/4
0
0
1
1
MCK/8
0
1
0
0
MCK/16
0
1
0
1
MCK/32
0
1
1
0
MCK/64
0
1
1
1
MCK/128
1
0
0
0
MCK/256
1
0
0
1
MCK/512
1
0
1
0
MCK/1024
1
0
1
1
CLKA
1
1
0
0
CLKB
Other
Reserved
• CALG: Channel Alignment
0 = The period is left aligned.
1 = The period is center aligned.
• CPOL: Channel Polarity
0 = The output waveform starts at a low level.
1 = The output waveform starts at a high level.
• CPD: Channel Update Period
0 = Writing to the PWM_CUPDx will modify the duty cycle at the next period start event.
1 = Writing to the PWM_CUPDx will modify the period at the next period start event.
706
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
38.6.10
PWM Channel Duty Cycle Register
Register Name:
PWM_CDTYx
Access Type:
Read/Write
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
CDTY
23
22
21
20
CDTY
15
14
13
12
CDTY
7
6
5
4
CDTY
Only the first Y bits (internal channel counter size) are significant.
• CDTY: Channel Duty Cycle
Defines the waveform duty cycle. This value must be defined between 0 and CPRD (PWM_CPRx).
707
6249B–ATARM–14-Dec-06
38.6.11
PWM Channel Period Register
Register Name:
PWM_CPRDx
Access Type:
Read/Write
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
CPRD
23
22
21
20
CPRD
15
14
13
12
CPRD
7
6
5
4
CPRD
Only the first Y bits (internal channel counter size) are significant.
• CPRD: Channel Period
If the waveform is left-aligned, then the output waveform period depends on the counter source clock and can be
calculated:
– By using the Master Clock (MCK) divided by an X given prescaler value (with X being 1, 2, 4, 8, 16, 32, 64, 128,
256, 512, or 1024). The resulting period formula will be:
(------------------------------X × CPRD )MCK
– By using a Master Clock divided by one of both DIVA or DIVB divider, the formula becomes, respectively:
(-----------------------------------------CRPD × DIVA )( CRPD × DIVAB )
or ----------------------------------------------MCK
MCK
If the waveform is center-aligned, then the output waveform period depends on the counter source clock and can be
calculated:
– By using the Master Clock (MCK) divided by an X given prescaler value (with X being 1, 2, 4, 8, 16, 32, 64, 128,
256, 512, or 1024). The resulting period formula will be:
(-----------------------------------------2 × X × CPRD )MCK
– By using a Master Clock divided by one of both DIVA or DIVB divider, the formula becomes, respectively:
(----------------------------------------------------2 × CPRD × DIVA )( 2 × CPRD × DIVB )
or -----------------------------------------------------MCK
MCK
708
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
38.6.12
PWM Channel Counter Register
Register Name:
PWM_CCNTx
Access Type:
Read-only
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
CNT
23
22
21
20
CNT
15
14
13
12
CNT
7
6
5
4
CNT
• CNT: Channel Counter Register
Internal counter value. This register is reset when:
• the channel is enabled (writing CHIDx in the PWM_ENA register).
• the counter reaches CPRD value defined in the PWM_CPRDx register if the waveform is left aligned.
38.6.13
PWM Channel Update Register
Register Name:
PWM_CUPDx
Access Type:
Write-only
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
CUPD
23
22
21
20
CUPD
15
14
13
12
CUPD
7
6
5
4
CUPD
This register acts as a double buffer for the period or the duty cycle. This prevents an unexpected waveform when modifying the waveform period or duty-cycle.
Only the first Y bits (internal channel counter size) are significant.
Table 38-5.
CPD (PWM_CMRx Register)
0
The duty-cycle (CDTC in the PWM_CDRx register) is updated with the CUPD value at the
beginning of the next period.
1
The period (CPRD in the PWM_CPRx register) is updated with the CUPD value at the beginning
of the next period.
709
6249B–ATARM–14-Dec-06
710
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
39. MultiMedia Card Interface (MCI)
39.1
Description
The MultiMedia Card Interface (MCI) supports the MultiMedia Card (MMC) Specification
V3.11, the SDIO Specification V1.1 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
2 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.
711
6249B–ATARM–14-Dec-06
39.2
Block Diagram
Figure 39-1. 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:
712
1. 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.
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
39.3
Application Block Diagram
Figure 39-2. Application Block Diagram
Application Layer
ex: File System, Audio, Security, etc.
Physical Layer
MCI Interface
1 2 3 4 5 6 78
1234567
9
SDCard
MMC
39.4
Pin Name List
Table 39-1.
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/SDIO
MCCK
Clock
I/O
CLK of an MMC or SD Card/SDIO
MCDA0 - MCDA3
Data 0..3 of Slot A
I/O/PP
DAT0 of an MMC
DAT[0..3] of an SD Card/SDIO
MCDB0 - MCDB3
Data 0..3 of Slot B
I/O/PP
DAT0 of an MMC
DAT[0..3] of an SD Card/SDIO
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.
39.5
Product Dependencies
39.5.1
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.
39.5.2
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.
713
6249B–ATARM–14-Dec-06
39.5.3
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.
39.6
Bus Topology
Figure 39-3. 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 39-2.
Bus Topology
Pin
Number
Name
Type(1)
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. 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.
Figure 39-4. MMC Bus Connections (One Slot)
MCI
MCDA0
MCCDA
MCCK
Note:
714
1234567
1234567
1234567
MMC1
MMC2
MMC3
When several MCI (x MCI) are embedded in a product, MCCK refers to MCIx_CK, MCCDA to MCIx_CDA MCDAy to MCIx_DAy.
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Figure 39-5. 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 39-3.
Table 39-3.
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 or Interrupt
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 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.
MCDA0 - MCDA3
MCCK
SD CARD
9
MCCDA
1 2 3 4 5 6 78
Figure 39-6. SD Card Bus Connections with One Slot
Note:
When several MCI (x MCI) are embedded in a product, MCCK refers to MCIx_CK, MCCDA to MCIx_CDA MCDAy to MCIx_DAy.
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6249B–ATARM–14-Dec-06
1 2 3 4 5 6 78
Figure 39-7. 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 MCI (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 39-8. 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 MCI (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 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.
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39.7
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 39-4 on page 718.
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 or when a multiple block transmission has a pre-defined block count (See
“Data Transfer Operation” on page 719.).
The MCI provides a set of registers to perform the entire range of MultiMedia Card operations.
39.7.1
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 2 PWSDIV + 1 when the bus is
inactive.
The two bits, RDPROOF and WRPROOF in the MCI Mode Register (MCI_MR) allow stopping
the MCI Clock during read or write access if the internal FIFO is full. This guarantees data
integrity, not bandwidth.
The command and the response of the card are clocked out with the rising edge of the MCI
Clock.
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All the timings for MultiMedia Card are defined in the MultiMediaCard System Specification.
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 39-4 and Table 39-5.
Table 39-4.
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 39-5.
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)
IOSPCMD (SDIO special command)
0 (not a special 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 39-5).
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.
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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.
Figure 39-9. 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
(1)
RETURN ERROR
RETURN OK
Note:
39.7.2
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 either in the mode register
MCI_MR, or in the Block Register MCI_BLKR. This field determines the size of the data block.
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Enabling PDC Force Byte Transfer (PDCFBYTE bit in the MCI_MR) allows the PDC to manage with internal byte transfers, so that transfer of blocks with a size different from modulo 4
can be supported. When PDC Force Byte Transfer is disabled, the PDC type of transfers are
in words, otherwise the type of transfers are in bytes.
Consequent to MMC Specification 3.1, two types of multiple block read (or write) transactions
are defined (the host can use either one at any time):
• Open-ended/Infinite Multiple block read (or write):
The number of blocks for the read (or write) multiple block operation is not defined. The
card continuously transfers (or programs) data blocks until a stop transmission command is
received.
• Multiple block read (or write) with pre-defined block count (since version 3.1 and higher):
The card transfers (or programs) the requested number of data blocks and terminate the
transaction. The stop command is not required at the end of this type of multiple block read
(or write), unless terminated with an error. In order to start a multiple block read (or write)
with pre-defined block count, the host must correctly program the MCI Block Register
(MCI_BLKR). Otherwise the card starts an open-ended multiple block read. The BCNT
field of the Block Register defines the number of blocks to transfer (from 1 to 65535
blocks). Programming the value 0 in the BCNT field corresponds to an infinite block
transfer.
39.7.3
Read Operation
The following flowchart shows how to read a single block with or without use of PDC facilities.
In this example (see Figure 39-10), a polling method is used to wait for the end of read. Similarly, the user can configure the interrupt enable register (MCI_IER) to trigger an interrupt at
the end of read.
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Figure 39-10. Read Functional Flow Diagram
Send SELECT/DESELECT_CARD
(1)
command
to select the card
Send SET_BLOCKLEN command(1)
No
Yes
Read with PDC
Reset the PDCMODE bit
MCI_MR &= ~PDCMODE
Set the block length (in bytes)
MCI_MR |= (BlockLenght <<16)(2)
Set the block count (if necessary)
MCI_BLKR |= (BlockCount << 0)
Set the PDCMODE bit
MCI_MR |= PDCMODE
Set the block length (in bytes)
MCI_MR |= (BlockLength << 16)(2)
Set the block count (if necessary)
MCI_BLKR |= (BlockCount << 0)
Configure the PDC channel
MCI_RPR = Data Buffer Address
MCI_RCR = BlockLength/4
MCI_PTCR = RXTEN
Send READ_SINGLE_BLOCK
command(1)
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 39-9).
2. This field is also accessible in the MCI Block Register (MCI_BLKR).
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39.7.4
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 39-11). 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 39-11. Write Functional Flow Diagram
Send SELECT/DESELECT_CARD
command(1) to select the card
Send SET_BLOCKLEN command(1)
Yes
No
Write using PDC
Set the PDCMODE bit
MCI_MR |= PDCMODE
Set the block length (in bytes)
MCI_MR |= (BlockLength << 16)(2)
Set the block count (if necessary)
MCI_BLKR |= (BlockCount << 0)
Reset the PDCMODE bit
MCI_MR &= ~PDCMODE
Set the block length (in bytes)
MCI_MR |= (BlockLenght <<16)(2)
Set the block count (if necessary)
MCI_BLKR |= (BlockCount << 0)
Configure the PDC channel
MCI_TPR = Data Buffer Address to write
MCI_TCR = BlockLength/4
Send WRITE_SINGLE_BLOCK
command(1)
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 39-9).
2. This field is also accessible in the MCI Block Register (MCI_BLKR).
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The following flowchart shows how to manage a multiple write block transfer with the PDC
(see Figure 39-12). 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).
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Figure 39-12. 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 (in bytes)
MCI_MR |= (BlockLength << 16)(2)
Set the block count (if necessary)
MCI_BLKR |= (BlockCount << 0)
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
command(1)
Poll the bit
NOTBUSY = 0?
Yes
No
RETURN
Note:
1. It is assumed that this command has been correctly sent (see Figure 39-9).
2. This field is also accessible in the MCI Block Register (MCI_BLKR).
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39.8
SD/SDIO Card Operations
The MultiMedia Card Interface allows processing of SD Memory (Secure Digital Memory
Card) and SDIO (SD Input Output) Card commands.
SD/SDIO 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 slots can
actually be used for more than flash memory cards. Devices that support SDIO can use small
devices designed for the SD form factor, such as GPS receivers, Wi-Fi or Bluetooth adapters,
modems, barcode readers, IrDA adapters, FM radio tuners, RFID readers, digital cameras and
more.
SD/SDIO is covered by numerous patents and trademarks, and licensing is only available
through the Secure Digital Card Association.
The SD/SDIO 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/SDIO Card and the MultiMedia Card is the initialization
process.
The SD/SDIO Card Register (MCI_SDCR) allows selection of the Card Slot and the data bus
width.
The SD/SDIO Card bus allows dynamic configuration of the number of data lines. After power
up, by default, the SD/SDIO Card uses only DAT0 for data transfer. After initialization, the host
can change the bus width (number of active data lines).
39.8.1
SDIO Data Transfer Type
SDIO cards may transfer data in either a multi-byte (1 to 512 bytes) or an optional block format
(1 to 511 blocks), while the SD memory cards are fixed in the block transfer mode. The
TRTYP field in the MCI Command Register (MCI_CMDR) allows to choose between SDIO
Byte or SDIO Block transfer.
The number of bytes/blocks to transfer is set through the BCNT field in the MCI Block Register
(MCI_BLKR). In SDIO Block mode, the field BLKLEN must be set to the data block size while
this field is not used in SDIO Byte mode.
An SDIO Card can have multiple I/O or combined I/O and memory (called Combo Card).
Within a multi-function SDIO or a Combo card, there are multiple devices (I/O and memory)
that share access to the SD bus. In order to allow the sharing of access to the host among
multiple devices, SDIO and combo cards can implement the optional concept of suspend/resume (Refer to the SDIO Specification for more details). To send a suspend or a
resume command, the host must set the SDIO Special Command field (IOSPCMD) in the MCI
Command Register.
39.8.2
SDIO Interrupts
Each function within an SDIO or Combo card may implement interrupts (Refer to the SDIO
Specification for more details). In order to allow the SDIO card to interrupt the host, an interrupt function is added to a pin on the DAT[1] line to signal the card’s interrupt to the host. An
SDIO interrupt on each slot can be enabled through the MCI Interrupt Enable Register. The
SDIO interrupt is sampled regardless of the currently selected slot.
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39.9
MultiMedia Card Interface (MCI) User Interface
Table 39-6.
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/SDIO Card Register
MCI_SDCR
Read/write
0x0
0x10
Argument Register
MCI_ARGR
Read/write
0x0
0x14
Command Register
MCI_CMDR
Write
–
0x18
Block Register
MCI_BLKR
Read/write
0x0
0x1C
Reserved
–
–
–
(1)
MCI_RSPR
Read
0x0
(1)
MCI_RSPR
Read
0x0
0x28
(1)
Response Register
MCI_RSPR
Read
0x0
0x2C
Response Register(1)
MCI_RSPR
Read
0x0
0x30
Receive Data Register
MCI_RDR
Read
0x0
0x34
Transmit Data Register
MCI_TDR
Write
–
–
–
–
0x20
0x24
0x38 - 0x3C
Response Register
Response Register
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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39.9.1
MCI Control Register
Name:
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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39.9.2
MCI Mode Register
Name:
MCI_MR
Access Type:
Read/write
31
30
29
28
27
26
25
24
19
18
17
16
10
9
8
BLKLEN
23
22
21
20
BLKLEN
15
14
13
12
11
PDCMODE
PDCPADV
PDCFBYTE
WRPROOF
RDPROOF
7
6
5
4
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).
• RDPROOF Read Proof Enable
Enabling Read Proof allows to stop the MCI Clock during read access if the internal FIFO is full. This guarantees data
integrity, not bandwidth.
0 = Disables Read Proof.
1 = Enables Read Proof.
• WRPROOF Write Proof Enable
Enabling Write Proof allows to stop the MCI Clock during write access if the internal FIFO is full. This guarantees data
integrity, not bandwidth.
0 = Disables Write Proof.
1 = Enables Write Proof.
• PDCFBYTE: PDC Force Byte Transfer
Enabling PDC Force Byte Transfer allows the PDC to manage with internal byte transfers, so that transfer of blocks with a
size different from modulo 4 can be supported.
Warning: BLKLEN value depends on PDCFBYTE.
0 = Disables PDC Force Byte Transfer. PDC type of transfer are in words.
1 = Enables PDC Force Byte Transfer. PDC type of transfer are in bytes.
• 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.
This field is also accessible in the MCI Block Register (MCI_BLKR).
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Bits 16 and 17 must be set to 0 if PDCFBYTE is disabled.
Note:
In SDIO Byte mode, BLKLEN field is not used.
39.9.3
MCI Data Timeout Register
Name:
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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39.9.4
MCI SDCard/SDIO Register
Name:
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/SDIO Slot
SDCSEL
SDCard/SDIO Slot
0
0
Slot A is selected.
0
1
Slot B selected
1
0
Reserved
1
1
Reserved
• SDCBUS: SDCard/SDIO Bus Width
0 = 1-bit data bus
1 = 4-bit data bus
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39.9.5
MCI Argument Register
Name:
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
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39.9.6
MCI Command Register
Name:
MCI_CMDR
Access Type:
Write-only
31
30
29
28
27
26
–
–
–
–
–
–
23
22
21
20
19
–
–
15
14
13
12
11
–
–
–
MAXLAT
OPDCMD
6
5
4
3
7
25
18
TRTYP
24
IOSPCMD
17
TRDIR
RSPTYP
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
733
6249B–ATARM–14-Dec-06
• 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
1
0
0
SDIO Byte
1
0
1
SDIO Block
1
1
0
Reserved
1
1
1
Reserved
• IOSPCMD: SDIO Special Command
IOSPCMD
734
SDIO Special Command Type
0
0
Not a SDIO Special Command
0
1
SDIO Suspend Command
1
0
SDIO Resume Command
1
1
Reserved
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
39.9.7
MCI Block Register
Name:
MCI_BLKR
Access Type:
Read/write
31
30
29
28
27
26
25
24
19
18
17
16
11
10
9
8
3
2
1
0
BLKLEN
23
22
21
20
BLKLEN
15
14
13
12
BCNT
7
6
5
4
BCNT
• BCNT: MMC/SDIO Block Count - SDIO Byte Count
This field determines the number of data byte(s) or block(s) to transfer.
The transfer data type and the authorized values for BCNT field are determined by the TRTYP field in the MCI Command
Register (MCI_CMDR):
TRTYP
Type of Transfer
BCNT Authorized Values
0
0
1
MMC/SDCard Multiple Block
From 1 to 65536: Value 0 corresponds to an infinite block transfer.
1
0
0
SDIO Byte
From 1 to 512 bytes: value 0 corresponds to a 512-byte transfer.
Values from 0x200 to 0xFFFF are forbidden.
1
0
1
SDIO Block
From 1 to 511 blocks: value 0 corresponds to an infinite block transfer.
Values from 0x200 to 0xFFFF are forbidden.
-
Reserved.
Other values
Warning: In SDIO Byte and Block modes, writing to the 7 last bits of BCNT field, is forbidden and may lead to unpredictable results.
• BLKLEN: Data Block Length
This field determines the size of the data block.
This field is also accessible in the MCI Mode Register (MCI_MR).
Bits 16 and 17 must be set to 0 if PDCFBYTE is disabled.
Note:
In SDIO Byte mode, BLKLEN field is not used.
735
6249B–ATARM–14-Dec-06
39.9.8
MCI Response Register
Name:
MCI_RSPR
Access Type:
Read-only
31
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:
736
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.
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
39.9.9
MCI Receive Data Register
Name:
MCI_RDR
Access Type:
Read-only
31
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
39.9.10
MCI Transmit Data Register
Name:
MCI_TDR
Access Type:
Write-only
31
30
29
28
DATA
23
22
21
20
DATA
15
14
13
12
DATA
7
6
5
4
DATA
• DATA: Data to Write
737
6249B–ATARM–14-Dec-06
39.9.11
MCI Status Register
Name:
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.
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.
738
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
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
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.
739
6249B–ATARM–14-Dec-06
• SDIOIRQA: SDIO Interrupt for Slot A
0 = No interrupt detected on SDIO Slot A.
1 = A SDIO Interrupt on Slot A has reached. Cleared when reading the MCI_SR.
• SDIOIRQB: SDIO Interrupt for Slot B
0 = No interrupt detected on SDIO Slot B.
1 = A SDIO Interrupt on Slot B has reached. Cleared when reading the MCI_SR.
• 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.
740
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
39.9.12
MCI Interrupt Enable Register
Name:
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
• SDIOIRQA: SDIO Interrupt for Slot A Interrupt Enable
• SDIOIRQB: SDIO Interrupt for Slot B 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.
1 = Enables the corresponding interrupt.
741
6249B–ATARM–14-Dec-06
39.9.13
MCI Interrupt Disable Register
Name:
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
• SDIOIRQA: SDIO Interrupt for Slot A Interrupt Disable
• SDIOIRQB: SDIO Interrupt for Slot B 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.
1 = Disables the corresponding interrupt.
742
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
39.9.14
MCI Interrupt Mask Register
Name:
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
• SDIOIRQA: SDIO Interrupt for Slot A Interrupt Mask
• SDIOIRQB: SDIO Interrupt for Slot B 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.
1 = The corresponding interrupt is enabled.
743
6249B–ATARM–14-Dec-06
744
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
40. Ethernet MAC 10/100 (EMACB)
40.1
Description
The EMAC module implements a 10/100 Ethernet MAC compatible with the IEEE 802.3 standard using an address checker, statistics and control registers, receive and transmit blocks,
and a DMA interface.
The address checker recognizes four specific 48-bit addresses and contains a 64-bit hash
register for matching multicast and unicast addresses. It can recognize the broadcast address
of all ones, copy all frames, and act on an external address match signal.
The statistics register block contains registers for counting various types of event associated
with transmit and receive operations. These registers, along with the status words stored in
the receive buffer list, enable software to generate network management statistics compatible
with IEEE 802.3.
40.2
Block Diagram
Figure 40-1. EMAC Block Diagram
Address Checker
APB
Slave
Register Interface
Statistics Registers
MDIO
Control Registers
DMA Interface
RX FIFO
TX FIFO
Ethernet Receive
MII/RMII
AHB
Master
Ethernet Transmit
745
6249B–ATARM–14-Dec-06
40.3
Functional Description
Figure 40-1 illustrates the different blocks of the EMAC module.
The control registers drive the MDIO interface, setup up DMA activity, start frame transmission
and select modes of operation such as full- or half-duplex.
The receive block checks for valid preamble, FCS, alignment and length, and presents
received frames to the address checking block and DMA interface.
746
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
The transmit block takes data from the DMA interface, adds preamble and, if necessary, pad
and FCS, and transmits data according to the CSMA/CD (carrier sense multiple access with
collision detect) protocol. The start of transmission is deferred if CRS (carrier sense) is active.
If COL (collision) becomes active during transmission, a jam sequence is asserted and the
transmission is retried after a random back off. CRS and COL have no effect in full duplex
mode.
The DMA block connects to external memory through its AHB bus interface. It contains
receive and transmit FIFOs for buffering frame data. It loads the transmit FIFO and empties
the receive FIFO using AHB bus master operations. Receive data is not sent to memory until
the address checking logic has determined that the frame should be copied. Receive or transmit frames are stored in one or more buffers. Receive buffers have a fixed length of 128 bytes.
Transmit buffers range in length between 0 and 2047 bytes, and up to 128 buffers are permitted per frame. The DMA block manages the transmit and receive framebuffer queues. These
queues can hold multiple frames.
40.3.1
Memory Interface
Frame data is transferred to and from the EMAC through the DMA interface. All transfers are
32-bit words and may be single accesses or bursts of 2, 3 or 4 words. Burst accesses do not
cross sixteen-byte boundaries. Bursts of 4 words are the default data transfer; single accesses
or bursts of less than four words may be used to transfer data at the beginning or the end of a
buffer.
The DMA controller performs six types of operation on the bus. In order of priority, these are:
1. Receive buffer manager write
2. Receive buffer manager read
3. Transmit data DMA read
4. Receive data DMA write
5. Transmit buffer manager read
6. Transmit buffer manager write
40.3.1.1
FIFO
The FIFO depths are Transmit_FIFO_size bytes and Receive_FIFO_size bytes and area function of the system clock speed, memory latency and network speed.
Data is typically transferred into and out of the FIFOs in bursts of four words. For receive, a
bus request is asserted when the FIFO contains four words and has space for three more. For
transmit, a bus request is generated when there is space for four words, or when there is
space for two words if the next transfer is to be only one or two words.
Thus the bus latency must be less than the time it takes to load the FIFO and transmit or
receive three words (12 bytes) of data.
At 100 Mbit/s, it takes 960 ns to transmit or receive 12 bytes of data. In addition, six master
clock cycles should be allowed for data to be loaded from the bus and to propagate through
the FIFOs. For a 60 MHz master clock this takes 100 ns, making the bus latency requirement
860 ns.
747
6249B–ATARM–14-Dec-06
40.3.1.2
Receive Buffers
Received frames, including CRC/FCS optionally, are written to receive buffers stored in memory. Each receive buffer is 128 bytes long. The start location for each receive buffer is stored
in memory in a list of receive buffer descriptors at a location pointed to by the receive buffer
queue pointer register. The receive buffer start location is a word address. For the first buffer
of a frame, the start location can be offset by up to three bytes depending on the value written
to bits 14 and 15 of the network configuration register. If the start location of the buffer is offset
the available length of the first buffer of a frame is reduced by the corresponding number of
bytes.
Each list entry consists of two words, the first being the address of the receive buffer and the
second being the receive status. If the length of a receive frame exceeds the buffer length, the
status word for the used buffer is written with zeroes except for the “start of frame” bit and the
offset bits, if appropriate. Bit zero of the address field is written to one to show the buffer has
been used. The receive buffer manager then reads the location of the next receive buffer and
fills that with receive frame data. The final buffer descriptor status word contains the complete
frame status. Refer to Table 40-1 for details of the receive buffer descriptor list.
Table 40-1.
Receive Buffer Descriptor Entry
Bit
Function
Word 0
31:2
Address of beginning of buffer
1
Wrap - marks last descriptor in receive buffer descriptor list.
0
Ownership - needs to be zero for the EMAC to write data to the receive buffer. The EMAC sets this to one once it has
successfully written a frame to memory.
Software has to clear this bit before the buffer can be used again.
Word 1
31
Global all ones broadcast address detected
30
Multicast hash match
29
Unicast hash match
28
External address match
27
Reserved for future use
26
Specific address register 1 match
25
Specific address register 2 match
24
Specific address register 3 match
23
Specific address register 4 match
22
Type ID match
21
VLAN tag detected (i.e., type id of 0x8100)
20
Priority tag detected (i.e., type id of 0x8100 and null VLAN identifier)
19:17
748
VLAN priority (only valid if bit 21 is set)
16
Concatenation format indicator (CFI) bit (only valid if bit 21 is set)
15
End of frame - when set the buffer contains the end of a frame. If end of frame is not set, then the only other valid status
are bits 12, 13 and 14.
AT91SAM9263 Preliminary
6249B–ATARM–14-Dec-06
AT91SAM9263 Preliminary
Table 40-1.
Receive Buffer Descriptor Entry (Continued)
Bit
Function
14
Start of frame - when set the buffer contains the start of a frame. If both bits 15 and 14 are set, then the buffer contains a
whole frame.
13:12
Receive buffer offset - indicates the number of bytes by which the data in the first buffer is offset from the word address.
Updated with the current values of the network configuration register. If jumbo frame mode is enabled through bit 3 of the
network configuration register, then bits 13:12 of the receive buffer descriptor entry are used to indicate bits 13:12 of the
frame length.
11:0
Length of frame including FCS (if selected). Bits 13:12 are also used if jumbo frame mode is selected.
To receive frames, the buffer descriptors must be initialized by writing an appropriate address
to bits 31 to 2 in the first word of each list entry. Bit zero must be written with zero. Bit one is
the wrap bit and indicates the last entry in the list.
The start location of the receive buffer descriptor list must be written to the receive buffer
queue pointer register before setting the receive enable bit in the network control register to
enable receive. As soon as the receive block starts writing received frame data to the receive
FIFO, the receive buffer manager reads the first receive buffer location pointed to by the
receive buffer queue pointer register.
If the filter block then indicates that 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 current buffer pointer has its wrap bit set or is the 1024th descriptor, the next
receive buffer location is read from the beginning of the receive descriptor list. Otherwise, the
next receive buffer location is read from the next word in memory.
There is an 11-bit counter to count out the 2048 word locations of a maximum length, receive
buffer descriptor list. This is added with the value originally written to the receive buffer queue
pointer register to produce a pointer into the list. A read of the receive buffer queue pointer
register returns the pointer value, which is the queue entry currently being accessed. The
counter is reset after receive status is written to a descriptor that has its wrap bit set or rolls
over to zero after 1024 descriptors have been accessed. The value written to the receive
buffer pointer register may be any word-aligned address, provided that there are at least 2048
word locations available between the pointer and the top of the memory.
Section 3.6 of the AMBA 2.0 specification states that bursts should not cross 1K boundaries.
As receive buffer manager writes are bursts of two words, to ensure that this does not occur, it
is best to write the pointer register with the least three significant bits set to zero. As receive
buffers are used, the receive buffer manager sets bit zero of the first word of the descriptor to
indicate used. If a receive error is detected the receive buffer currently being written is recovered. Previous buffers are not recovered. Software should search through the used bits in the
buffer descriptors to find out how many frames have been received. It should be checking the
start-of-frame and end-of-frame bits, and not rely on the value returned by the receive buffer
queue pointer register which changes continuously as more buffers are used.
For CRC errored frames, excessive length frames or length field mismatched frames, all of
which are counted in the statistics registers, it is possible that a frame fragment might be
stored in a sequence of receive buffers. Software can detect this by looking for start of frame
bit set in a buffer following a buffer with no end of frame bit set.
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For a properly working Ethernet system, there should be no excessively long frames or frames
greater than 128 bytes with CRC/FCS errors. Collision fragments are less than 128 bytes long.
Therefore, it is a rare occurrence to find a frame fragment in a receive buffer.
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 not available bit in the
receive status register and triggers an interrupt.
If bit zero is set when the receive buffer manager reads the location of the receive buffer and a
frame is being received, the frame is discarded and the receive resource error statistics register is incremented.
A receive overrun condition occurs when bus was not granted in time or because HRESP was
not OK (bus error). In a receive overrun condition, the receive overrun interrupt is asserted
and the buffer currently being written is recovered. The next frame received with an address
that is recognized reuses the buffer.
If bit 17 of the network configuration register is set, the FCS of received frames shall not be
copied to memory. The frame length indicated in the receive status field shall be reduced by
four bytes in this case.
40.3.1.3
Transmit Buffer
Frames to be transmitted are stored in one or more transmit buffers. Transmit buffers can be
between 0 and 2047 bytes long, so it is possible to transmit frames longer than the maximum
length specified in IEEE Standard 802.3. Zero length buffers are allowed. The maximum number of buffers permitted for each transmit frame is 128.
The start location for each transmit buffer is stored in memory in a list of transmit buffer
descriptors at a location pointed to by the transmit buffer queue pointer register. Each list entry
consists of two words, the first being the byte address of the transmit buffer and the second
containing the transmit control and status. Frames can be transmitted with or without automatic CRC generation. If CRC is automatically generated, pad is also automatically generated
to take frames to a minimum length of 64 bytes. Table 40-2 on page 751 defines an entry in
the transmit buffer descriptor list. To transmit frames, the buffer descriptors must be initialized
by writing an appropriate byte address to bits 31 to 0 in the first word of each list entry. The
second transmit buffer descriptor is initialized with control information that indicates the length
of the buffer, whether or not it is to be transmitted with CRC and whether the buffer is the last
buffer in the frame.
After transmission, the control bits are written back to the second word of the first buffer along
with the “used” bit and other status information. Bit 31 is the “used” bit which must be zero
when the control word is read if transmission is to happen. It is written to one when a frame
has been transmitted. Bits 27, 28 and 29 indicate various transmit error conditions. Bit 30 is
the “wrap” bit which can be set for any buffer within a frame. If no wrap bit is encountered after
1024 descriptors, the queue pointer rolls over to the start in a similar fashion to the receive
queue.
The transmit buffer queue pointer register must not be written while transmit is active. If a new
value is written to the transmit buffer queue pointer register, the queue pointer resets itself to
point to the beginning of the new queue. If transmit is disabled by writing to bit 3 of the network
control, the transmit buffer queue pointer register resets to point to the beginning of the trans-
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mit queue. Note that disabling receive does not have the same effect on the receive queue
pointer.
Once the transmit queue is initialized, transmit is activated by writing to bit 9, the Transmit
Start bit of the network control register. Transmit is halted when a buffer descriptor with its
used bit set is read, or if a transmit error occurs, or by writing to the transmit halt bit of the network control register. (Transmission is suspended if a pause frame is received while the pause
enable bit is set in the network configuration register.) Rewriting the start bit while transmission
is active is allowed.
Transmission control is implemented with a Tx_go variable which is readable in the transmit
status register at bit location 3. The Tx_go variable is reset when:
– transmit is disabled
– a buffer descriptor with its ownership bit set is read
– a new value is written to the transmit buffer queue pointer register
– bit 10, tx_halt, of the network control register is written
– there is a transmit error such as too many retries or a transmit underrun.
To set tx_go, write to bit 9, tx_start, of the network control register. Transmit halt does not take
effect until any ongoing transmit finishes. If a collision occurs during transmission of a multibuffer frame, transmission automatically restarts from the first buffer of the frame. If a “used”
bit is read midway through transmission of a multi-buffer frame, this is treated as a transmit
error. Transmission stops, tx_er is asserted and the FCS is bad.
If transmission stops due to a transmit error, the transmit queue pointer resets to point to the
beginning of the transmit queue. Software needs to re-initialize the transmit queue after a
transmit error.
If transmission stops due to a “used” bit being read at the start of the frame, the transmission
queue pointer is not reset and transmit starts from the same transmit buffer descriptor when
the transmit start bit is written
Table 40-2.
Transmit Buffer Descriptor Entry
Bit
Function
Word 0
31:0
Byte Address of buffer
Word 1
31
Used. Needs to be zero for the EMAC to read data from the transmit buffer. The EMAC sets this to one for the first buffer
of a frame once it has been successfully transmitted.
Software has to clear this bit before the buffer can be used again.
Note:
This bit is only set for the first buffer in a frame unlike receive where all buffers have the Used bit set once used.
30
Wrap. Marks last descriptor in transmit buffer descriptor list.
29
Retry limit exceeded, transmit error detected
28
Transmit underrun, occurs either when hresp is not OK (bus error) or the transmit data could not be fetched in time or
when buffers are exhausted in mid frame.
27
Buffers exhausted in mid frame
26:17
16
Reserved
No CRC. When set, no CRC is appended to the current frame. This bit only needs to be set for the last buffer of a frame.
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Table 40-2.
Transmit Buffer Descriptor Entry
Bit
Function
15
Last buffer. When set, this bit indicates the last buffer in the current frame has been reached.
14:11
Reserved
10:0
Length of buffer
40.3.2
Transmit Block
This block transmits frames in accordance with the Ethernet IEEE 802.3 CSMA/CD protocol.
Frame assembly starts by adding preamble and the start frame delimiter. Data is taken from
the transmit FIFO a word at a time. Data is transmitted least significant nibble first. If necessary, padding is added to increase the frame length to 60 bytes. CRC is calculated as a 32-bit
polynomial. This is inverted and appended to the end of the frame, taking the frame length to a
minimum of 64 bytes. If the No CRC bit is set in the second word of the last buffer descriptor of
a transmit frame, neither pad nor CRC are appended.
In full-duplex mode, frames are transmitted immediately. Back-to-back frames are transmitted
at least 96 bit times apart to guarantee the interframe 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 interframe 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 retry transmission after the back off time has elapsed.
The back-off time is based on an XOR of the 10 least significant bits of the data coming from
the transmit FIFO and a 10-bit pseudo random number generator. The number of bits used
depends on the number of collisions seen. After the first collision, 1 bit is used, after the second 2, and so on up to 10. Above 10, all 10 bits are used. An error is indicated and no further
attempts are made if 16 attempts cause collisions.
If transmit DMA underruns, bad CRC is automatically appended using the same mechanism
as jam insertion and the tx_er signal is asserted. For a properly configured system, this should
never happen.
If the back pressure bit is set in the network control register in half duplex mode, the transmit
block transmits 64 bits of data, which can consist of 16 nibbles of 1011 or in bit-rate mode 64
1s, whenever it sees an incoming frame to force a collision. This provides a way of implementing flow control in half-duplex mode.
40.3.3
Pause Frame Support
The start of an 802.3 pause frame is as follows:
Table 40-3.
Start of an 802.3 Pause Frame
Destination
Address
Source
Address
Type
(Mac Control Frame)
Pause
Opcode
Pause Time
0x0180C2000001
6 bytes
0x8808
0x0001
2 bytes
The network configuration register contains a receive pause enable bit (13). If a valid pause
frame is received, the pause time register is updated with the frame’s pause time, regardless
of its current contents and regardless of the state of the configuration register bit 13. An inter-
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rupt (12) is triggered when a pause frame is received, assuming it is enabled in the interrupt
mask register. If bit 13 is set in the network configuration register and the value of the pause
time register is non-zero, no new frame is transmitted until the pause time register has decremented to zero.
The loading of a new pause time, and hence the pausing of transmission, only occurs when
the EMAC is configured for full-duplex operation. If the EMAC is configured for half-duplex,
there is no transmission pause, but the pause frame received interrupt is still triggered.
A valid pause frame is defined as having a destination address that matches either the
address stored in specific address register 1 or matches 0x0180C2000001 and has the MAC
control frame type ID of 0x8808 and the pause opcode of 0x0001. Pause frames that have
FCS or other errors are treated as invalid and are discarded. Valid pause frames received
increment the Pause Frame Received statistic register.
The pause time register decrements every 512 bit times (i.e., 128 rx_clks in nibble mode)
once transmission has stopped. For test purposes, the register decrements every rx_clk
cycle once transmission has stopped if bit 12 (retry test) is set in the network configuration register. If the pause enable bit (13) is not set in the network configuration register, then the
decrementing occurs regardless of whether transmission has stopped or not.
An interrupt (13) is asserted whenever the pause time register decrements to zero (assuming
it is enabled in the interrupt mask register).
40.3.4
Receive Block
The receive block checks for valid preamble, FCS, alignment and length, presents received
frames to the DMA block and stores the frames destination address for use by the address
checking block. If, during frame reception, the frame is found to be too long or rx_er is
asserted, a bad frame indication is sent to the DMA block. The DMA block then ceases sending data to memory. At the end of frame reception, the receive block indicates to the DMA
block whether the frame is good or bad. The DMA block recovers the current receive buffer if
the frame was bad. The receive block signals the register block to increment the alignment
error, the CRC (FCS) error, the short frame, long frame, jabber error, the receive symbol error
statistics and the length field mismatch statistics.
The enable bit for jumbo frames in the network configuration register allows the EMAC to
receive jumbo frames of up to 10240 bytes in size. This operation does not form part of the
IEEE802.3 specification and is disabled by default. When jumbo frames are enabled, frames
received with a frame size greater than 10240 bytes are discarded.
40.3.5
Address Checking Block
The address checking (or filter) block indicates to the DMA block which receive frames should
be copied to memory. Whether a frame is copied depends on what is enabled in the network
configuration register, the state of the external match pin, the contents of the specific address
and hash registers and the frame’s destination address. In this implementation of the EMAC,
the frame’s source address is not checked. Provided that bit 18 of the Network Configuration
register is not set, a frame is not copied to memory if the EMAC is transmitting in half duplex
mode at the time a destination address is received. If bit 18 of the Network Configuration register is set, frames can be received while transmitting in half-duplex mode.
Ethernet frames are transmitted a byte at a time, least significant bit first. The first six bytes (48
bits) of an Ethernet frame make up the destination address. The first bit of the destination
address, the LSB of the first byte of the frame, is the group/individual bit: this is One for multi-
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cast addresses and Zero for unicast. The All Ones address is the broadcast address, and a
special case of multicast.
The EMAC supports recognition of four specific addresses. Each specific address requires
two registers, specific address register bottom and specific address register top. Specific
address register bottom stores the first four bytes of the destination address and specific
address register top contains the last two bytes. The addresses stored can be specific, group,
local or universal.
The destination address of received frames is compared against the data stored in the specific
address registers once they have been activated. The addresses are deactivated at reset or
when their corresponding specific address register bottom is written. They are activated when
specific address register top is written. If a receive frame address matches an active address,
the frame is copied to memory.
The following example illustrates the use of the address match registers for a MAC address of
21:43:65:87:A9:CB.
Preamble 55
SFD D5
DA (Octet0 - LSB) 21
DA(Octet 1) 43
DA(Octet 2) 65
DA(Octet 3) 87
DA(Octet 4) A9
DA (Octet5 - MSB) CB
SA (LSB) 00
SA 00
SA 00
SA 00
SA 00
SA (MSB) 43
SA (LSB) 21
The sequence above shows the beginning of an Ethernet frame. Byte order of transmission is
from top to bottom as shown. For a successful match to specific address 1, the following
address matching registers must be set up:
• Base address + 0x98 0x87654321 (Bottom)
• Base address + 0x9C 0x0000CBA9 (Top)
And for a successful match to the Type ID register, the following should be set up:
• Base address + 0xB8 0x00004321
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40.3.6
Broadcast Address
The broadcast address of 0xFFFFFFFFFFFF is recognized if the ‘no broadcast’ bit in the network configuration register is zero.
40.3.7
Hash Addressing
The hash address register is 64 bits long and takes up two locations in the memory map. The
least significant bits are stored in hash register bottom and the most significant bits in hash
register top.
The unicast hash enable and the multicast hash enable bits in the network configuration register enable the reception of hash matched frames. The destination address is reduced to a 6-bit
index into the 64-bit hash register using the following hash function. The hash function is an
exclusive or of every sixth bit of the destination address.
hash_index[5] = da[5] ^ da[11] ^ da[17] ^ da[23] ^ da[29] ^ da[35] ^ da[41] ^ da[47]
hash_index[4] = da[4] ^ da[10] ^ da[16] ^ da[22] ^ da[28] ^ da[34] ^ da[40] ^ da[46]
hash_index[3] = da[3] ^ da[09] ^ da[15] ^ da[21] ^ da[27] ^ da[33] ^ da[39] ^ da[45]
hash_index[2] = da[2] ^ da[08] ^ da[14] ^ da[20] ^ da[26] ^ da[32] ^ da[38] ^ da[44]
hash_index[1] = da[1] ^ da[07] ^ da[13] ^ da[19] ^ da[25] ^ da[31] ^ da[37] ^ da[43]
hash_index[0] = da[0] ^ da[06] ^ da[12] ^ da[18] ^ da[24] ^ da[30] ^ da[36] ^ da[42]
da[0] represents the least significant bit of the first byte received, that is, the multicast/unicast indicator, and da[47] represents the most significant bit of the last byte received.
If the hash index points to a bit that is set in the hash register, then the frame is matched
according to whether the frame is multicast or unicast.
A multicast match is signalled if the multicast hash enable bit is set. da[0] is 1 and the hash
index points to a bit set in the hash register.
A unicast match is signalled if the unicast hash enable bit is set. da[0] is 0 and the hash index
points to a bit set in the hash register.
To receive all multicast frames, the hash register should be set with all ones and the multicast
hash enable bit should be set in the network configuration register.
40.3.8
Copy All Frames (or Promiscuous Mode)
If the copy all frames bit is set in the network configuration register, then all non-errored
frames are copied to memory. For example, frames that are too long, too short, or have FCS
errors or rx_er asserted during reception are discarded and all others are received. Frames
with FCS errors are copied to memory if bit 19 in the network configuration register is set.
40.3.9
Type ID Checking
The contents of the type_id register are compared against the length/type ID of received
frames (i.e., bytes 13 and 14). Bit 22 in the receive buffer descriptor status is set if there is a
match. The reset state of this register is zero which is unlikely to match the length/type ID of
any valid Ethernet frame.
Note:
A type ID match does not affect whether a frame is copied to memory.
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40.3.10
VLAN Support
An Ethernet encoded 802.1Q VLAN tag looks like this:
Table 40-4.
802.1Q VLAN Tag
TPID (Tag Protocol Identifier) 16 bits
TCI (Tag Control Information) 16 bits
0x8100
First 3 bits priority, then CFI bit, last 12 bits VID
The VLAN tag is inserted at the 13th byte of the frame, adding an extra four bytes to the frame.
If the VID (VLAN identifier) is null (0x000), this indicates a priority-tagged frame. The MAC can
support frame lengths up to 1536 bytes, 18 bytes more than the original Ethernet maximum
frame length of 1518 bytes. This is achieved by setting bit 8 in the network configuration
register.
The following bits in the receive buffer descriptor status word give information about VLAN
tagged frames:
• Bit 21 set if receive frame is VLAN tagged (i.e. type id of 0x8100)
• Bit 20 set if receive frame is priority tagged (i.e. type id of 0x8100 and null VID). (If bit 20 is
set bit 21 is set also.)
• Bit 19, 18 and 17 set to priority if bit 21 is set
• Bit 16 set to CFI if bit 21 is set
40.3.11
PHY Maintenance
The register EMAC_MAN enables the EMAC to communicate with a PHY by means of the
MDIO interface. It is used during auto-negotiation to ensure that the EMAC and the PHY are
configured for the same speed and duplex configuration.
The PHY maintenance register is implemented as a shift register. Writing to the register starts
a shift operation which is signalled as complete when bit two is set in the network status register (about 2000 MCK cycles later when bit ten is set to zero, and bit eleven is set to one in the
network configuration register). An interrupt is generated as this bit is set. During this time, the
MSB of the register is output on the MDIO pin and the LSB updated from the MDIO pin with
each MDC cycle. This causes transmission of a PHY management frame on MDIO.
Reading during the shift operation returns the current contents of the shift register. At the end
of management operation, the bits have shifted back to their original locations. For a read
operation, the data bits are updated with data read from the PHY. It is important to write the
correct values to the register to ensure a valid PHY management frame is produced.
The MDIO interface can read IEEE 802.3 clause 45 PHYs as well as clause 22 PHYs. To read
clause 45 PHYs, bits[31:28] should be written as 0x0011. For a description of MDC generation, see the network configuration register in the ”Network Control Register” on page 763.
40.3.12
756
Media Independent Interface
The Ethernet MAC is capable of interfacing to both RMII and MII Interfaces. The RMII bit in the
EMAC_USRIO register controls the interface that is selected. When this bit is set, the RMII
interface is selected, else the MII interface is selected.
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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
Table 40-5.
Table 40-5.
Pin Configuration
Pin Name
ETXCK_EREFCK
MII
RMII
ETXCK: Transmit Clock
EREFCK: Reference Clock
ECRS
ECRS: Carrier Sense
ECOL
ECOL: Collision Detect
ERXDV
ERXDV: Data Valid
ECRSDV: Carrier Sense/Data Valid
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: 4-bit Transmit Data
ETX0 - ETX1: 2-bit Transmit Data
ERX0 - ERX3
ETX0-ETX3
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_EREFCK) for 100Mb/s data rate.
40.3.12.1
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 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.
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40.4
Programming Interface
40.4.1
40.4.1.1
Initialization
Configuration
Initialization of the EMAC configuration (e.g., loop-back mode, frequency ratios) must be done
while the transmit and receive circuits are disabled. See the description of the network control
register and network configuration register earlier in this document.
To change loop-back mode, the following sequence of operations must be followed:
1. Write to network control register to disable transmit and receive circuits.
2. Write to network control register to change loop-back mode.
3. Write to network control register to re-enable transmit or receive circuits.
Note:
40.4.1.2
These writes to network control register cannot be combined in any way.
Receive Buffer List
Receive data is written to areas of data (i.e., buffers) in system memory. These buffers are
listed in another data structure that also resides in main memory. This data structure (receive
buffer queue) is a sequence of descriptor entries as defined in ”Receive Buffer Descriptor
Entry” on page 748. It points to this data structure.
Figure 40-2. Receive Buffer List
Receive Buffer 0
Receive Buffer Queue Pointer
(MAC Register)
Receive Buffer 1
Receive Buffer N
Receive Buffer Descriptor List
(In memory)
(In memory)
To create the list of buffers:
1. Allocate a number (n) of buffers of 128 bytes in system memory.
2. Allocate an area 2n words for the receive buffer descriptor entry in system memory
and create n entries in this list. Mark all entries in this list as owned by EMAC, i.e., bit
0 of word 0 set to 0.
3. If less than 1024 buffers are defined, the last descriptor must be marked with the
wrap bit (bit 1 in word 0 set to 1).
4. Write address of receive buffer descriptor entry to EMAC register receive_buffer
queue pointer.
5. The receive circuits can then be enabled by writing to the address recognition registers and then to the network control register.
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40.4.1.3
Transmit Buffer List
Transmit data is read from areas of data (the buffers) in system memory These buffers are
listed in another data structure that also resides in main memory. This data structure (Transmit
Buffer Queue) is a sequence of descriptor entries (as defined in Table 40-2 on page 751) that
points to this data structure.
To create this list of buffers:
1. Allocate a number (n) of buffers of between 1 and 2047 bytes of data to be transmitted in system memory. Up to 128 buffers per frame are allowed.
2. Allocate an area 2n words for the transmit buffer descriptor entry in system memory
and create N entries in this list. Mark all entries in this list as owned by EMAC, i.e. bit
31 of word 1 set to 0.
3. If fewer than 1024 buffers are defined, the last descriptor must be marked with the
wrap bit — bit 30 in word 1 set to 1.
4. Write address of transmit buffer descriptor entry to EMAC register transmit_buffer
queue pointer.
5. The transmit circuits can then be enabled by writing to the network control register.
40.4.1.4
Address Matching
The EMAC register-pair hash address and the four specific address register-pairs must be
written with the required values. Each register-pair comprises a bottom register and top register, with the bottom register being written first. The address matching is disabled for a
particular register-pair after the bottom-register has been written and re-enabled when the top
register is written. See “Address Checking Block” on page 753. for details of address matching. Each register-pair may be written at any time, regardless of whether the receive circuits
are enabled or disabled.
40.4.1.5
Interrupts
There are 14 interrupt conditions that are detected within the EMAC. These are ORed to make
a single interrupt. Depending on the overall system design, this may be passed through a further level of interrupt collection (interrupt controller). On receipt of the interrupt signal, the CPU
enters the interrupt handler (Refer to the AIC programmer datasheet). To ascertain which
interrupt has been generated, read the interrupt status register. Note that this register clears
itself when read. At reset, all interrupts are disabled. To enable an interrupt, write to interrupt
enable register with the pertinent interrupt bit set to 1. To disable an interrupt, write to interrupt
disable register with the pertinent interrupt bit set to 1. To check whether an interrupt is
enabled or disabled, read interrupt mask register: if the bit is set to 1, the interrupt is disabled.
40.4.1.6
Transmitting Frames
To set up a frame for transmission:
1. Enable transmit in the network control register.
2. Allocate an area of system memory for transmit data. This does not have to be contiguous, varying byte lengths can be used as long as they conclude on byte borders.
3. Set-up the transmit buffer list.
4. Set the network control register to enable transmission and enable interrupts.
5. Write data for transmission into these buffers.
6. Write the address to transmit buffer descriptor queue pointer.
7. Write control and length to word one of the transmit buffer descriptor entry.
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8. Write to the transmit start bit in the network control register.
40.4.1.7
Receiving Frames
When a frame is received and the receive circuits are enabled, the EMAC checks the address
and, in the following cases, the frame is written to system memory:
• if it matches one of the four specific address registers.
• if it matches the hash address function.
• if it is a broadcast address (0xFFFFFFFFFFFF) and broadcasts are allowed.
• if the EMAC is configured to copy all frames.
The register receive buffer queue pointer points to the next entry (see Table 40-1 on page
748) and the EMAC uses this as the address in system memory to write the frame to. Once
the frame has been completely and successfully received and written to system memory, the
EMAC then updates the receive buffer descriptor entry with the reason for the address match
and marks the area as being owned by software. Once this is complete an interrupt receive
complete is set. Software is then responsible for handling the data in the buffer and then
releasing the buffer by writing the ownership bit back to 0.
If the EMAC is unable to write the data at a rate to match the incoming frame, then an interrupt
receive overrun is set. If there is no receive buffer available, i.e., the next buffer is still owned
by software, the interrupt receive buffer not available is set. If the frame is not successfully
received, a statistic register is incremented and the frame is discarded without informing
software.
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40.5
Ethernet MAC 10/100 (EMAC) User Interface
Table 40-6.
Ethernet MAC 10/100 (EMAC) Register Mapping
Offset
Register
Name
Access
Reset Value
0x00
Network Control Register
EMAC_NCR
Read/Write
0
0x04
Network Configuration Register
EMAC_NCFG
Read/Write
0x800
0x08
Network Status Register
EMAC_NSR
Read-only
-
0x0C
Reserved
0x10
Reserved
0x14
Transmit Status Register
EMAC_TSR
Read/Write
0x0000_0000
0x18
Receive Buffer Queue Pointer Register
EMAC_RBQP
Read/Write
0x0000_0000
0x1C
Transmit Buffer Queue Pointer Register
EMAC_TBQP
Read/Write
0x0000_0000
0x20
Receive Status Register
EMAC_RSR
Read/Write
0x0000_0000
0x24
Interrupt Status Register
EMAC_ISR
Read/Write
0x0000_0000
0x28
Interrupt Enable Register
EMAC_IER
Write-only
-
0x2C
Interrupt Disable Register
EMAC_IDR
Write-only
-
0x30
Interrupt Mask Register
EMAC_IMR
Read-only
0x0000_3FFF
0x34
Phy Maintenance Register
EMAC_MAN
Read/Write
0x0000_0000
0x38
Pause Time Register
EMAC_PTR
Read/Write
0x0000_0000
0x3C
Pause Frames Received Register
EMAC_PFR
Read/Write
0x0000_0000
0x40
Frames Transmitted Ok Register
EMAC_FTO
Read/Write
0x0000_0000
0x44
Single Collision Frames Register
EMAC_SCF