AT91SAM7X128 Atmel, AT91SAM7X128 Datasheet - Page 664

• Manufacturer Part Number: AT91SAM7X128
• Description: MCU 32-Bit 91S ARM7TDMI RISC 128KB Flash 1.8V/3.3V 100-Pin LQFP
• Manufacturer: Atmel

Specifications of AT91SAM7X128

• Package: 100LQFP
• Device Core: ARM7TDMI
• Family Name: 91S
• Maximum Speed: 55 MHz
• Ram Size: 32 KB
• Program Memory Size: 128 KB
• Operating Supply Voltage: 1.8|3.3 V
• Data Bus Width: 32 Bit
• Program Memory Type: Flash
• Number Of Programmable I/os: 62
• Interface Type: CAN/Ethernet/SPI/I2S/TWI/USART/USB
• On-chip Adc: 8-chx10-bit
• Operating Temperature: -40 to 85 °C
• Number Of Timers: 3

41.4.7.5
41.4.7.6
41.4.7.7
41.4.8
41.4.8.1
664
AT91SAM7X512/256/128 Preliminary
Synchronous Serial Controller (SSC)
SPI: Baudrate Set to 1
SPI: Bad Serial Clock Generation on 2nd Chip Select
SPI: Software Reset must be Written Twice
SSC: Periodic Transmission Limitations in Master Mode
transfer is performed in Fixed mode through the PDC, on Chip select 1, the transfer will be con-
sidered as a HalfWord transfer.
If a PDC transfer has to be performed in 8 bits, on a Chip select y (y as different from 0), the
BITS field of the SPI_CSR0 must be configured in 8 bits, in the same way as the BITS field of
the CSRy Register.
When Baudrate is set at 1 (i.e. when serial clock frequency equals the system clock frequency)
and when the BITS field of the SPI_CSR register (number of bits to be transmitted) equals an
ODD value (in this case 9,11,13 or 15), an additional pulse will be generated on output SPCK.
Everything is OK if the BITS field equals 8,10,12,14 or 16 and Baudrate = 1.
None.
Bad Serial clock generation on the 2nd chip select when SCBR = 1, CPOL = 1 and NCPHA = 0.
This occurs using SPI with the following conditions:
Do not use a multiple Chip Select configuration where at least one SCRx register is configured
with SCBR = 1 and the others differ from 1 if NCPHA = 0 and CPOL = 1.
If all chip selects are configured with Baudrate = 1, the issue does not appear.
If a software reset (SWRST in the SPI Control Register) is performed, the SPI may not work
properly (the clock is enabled before the chip select.)
The SPI Control Register field, SWRST (Software Reset) needs to be written twice to be cor-
rectly set.
If the Least Significant Bit is sent first (MSBF = 0), the first TAG during the frame synchro is not
sent.
None.
• Master Mode
• CPOL = 1 and NCPHA = 0
• Multiple chip selects are used with one transfer with Baud rate (SCBR) equal to 1 (i.e., when
• Transmitting with the slowest chip select and then with the fastest one, then an additional
serial clock frequency equals the system clock frequency) and the other transfers set with
SCBR are not equal to 1
pulse is generated on output SPCK during the second transfer.
Problem Fix/Workaround
Problem Fix/Workaround
Problem Fix/Workaround
Problem Fix/Workaround
Problem Fix/Workaround
6120H–ATARM–17-Feb-09