AT91SAM7S256D-AU Atmel, AT91SAM7S256D-AU Datasheet - Page 621

• Manufacturer Part Number: AT91SAM7S256D-AU
• Description: ARM Microcontrollers - MCU 256K Flash SRAM 64K ARM based MCU
• Manufacturer: Atmel
• Series: SAM7S256r

Specifications of AT91SAM7S256D-AU

• Rohs: yes
• Core: ARM
• Processor Series: AT91SAM
• Data Bus Width: 16 bit/32 bit
• Maximum Clock Frequency: 55 MHz
• Program Memory Size: 256 KB
• Data Ram Size: 64 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 3 V to 3.6 V
• Operating Temperature Range: - 40 C to + 85 C
• Package / Case: LQFP-64
• Mounting Style: SMD/SMT
• Interface Type: 2-Wire, I2S, SPI, USART
• Length: 7 mm

40.6.11
40.6.11.1
40.6.11.2
40.6.11.3
40.6.11.4
The data need to be delayed for one bit clock period with an external assembly. In the following schematic, TD, TK
and NRST are SAM7S signals, TXD is the delayed data to connect to the device.
The value of CLDIV x 2
equal to 8191
None.
When a software reset is performed during a frame and when TWCK is low, it is impossible to initiate a new trans-
fer in READ or WRITE mode.
None.
Any transfer in progress is immediately frozen if the Control Register (TWI_CR) is written with the bit MSDIS at 1.
Furthermore, the status bits TXCOMP and TXRDY in the Status Register (TWI_SR) are not reset.
The user must wait for the end of transfer before disabling the TWI. In addition, the interrupts must be disabled
before disabling the TWI.
During a master frame, if TWI_SR is read between the Non Acknowledge condition detection and the TXCOMP bit
rising in the TWI_SR, the NACK bit is not set.
The user must wait for the TXCOMP status bit by interrupt and must not read the TWI_SR as long as transmission
is not completed.
Two-wire Interface (TWI)
Problem Fix/Workaround
Problem Fix/Workaround
Problem Fix/Workaround
Problem Fix/Workaround
Problem Fix/Workaround
TWI: Clock Divider
TWI: Software Reset
TWI: Disabling Does not Operate Correctly
TWI: NACK Status Bit Lost
CKDIV
must be less than or equal to 8191, the value of CHDIV x 2
SAM7S Series [DATASHEET]
CKDIV
6175M–ATARM–26-Oct-12
must be less than or
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