at91sam9263 ATMEL Corporation, at91sam9263 Datasheet - Page 511

• Manufacturer Part Number: at91sam9263
• Description: At91 Arm Thumb Microcontrollers
• Manufacturer: ATMEL Corporation

33.6
33.6.1
6249D–ATARM–20-Dec-07
Functional Description
Baud Rate Generator
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 pro-
vided 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
– 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
– 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
– NACK handling, error counter with repetition and iteration limit
– Remote loopback, local loopback, automatic echo
AT91SAM9263 Preliminary
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