AT91SAM7S256D-AU Atmel, AT91SAM7S256D-AU Datasheet - Page 364

• 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

31.6
31.6.1
Functional Description
The USART is capable of managing several types of serial synchronous or asynchronous communications.
It supports the following communication modes:
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 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.
• 5- to 9-bit full-duplex asynchronous serial communication
• High-speed 5- to 9-bit full-duplex synchronous serial communication
• RS485 with driver control signal
• ISO7816, T0 or T1 protocols for interfacing with smart cards
• InfraRed IrDA Modulation and Demodulation
• Test modes
• 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
Baud Rate Generator
– MSB- or LSB-first
– 1, 1.5 or 2 stop bits
– Parity even, odd, marked, space or none
– By 8 or by 16 over-sampling receiver frequency
– Optional hardware handshaking
– Optional modem signals management (SAM7S512/256/128/64/321/161)
– Optional break management
– Optional multidrop serial communication
– MSB- or LSB-first
– 1 or 2 stop bits
– Parity even, odd, marked, space or none
– By 8 or by 16 over-sampling frequency
– Optional hardware handshaking
– Optional modem signals management (SAM7S512/256/128/64/321/161)
– Optional break management
– Optional multidrop serial communication
– NACK handling, error counter with repetition and iteration limit
– Remote loopback, local loopback, automatic echo
SAM7S Series [DATASHEET]
6175M–ATARM–26-Oct-12
364