Atmel ARM-Based Evaluation Kit AT91SAM9N12-EK AT91SAM9N12-EK Data Sheet
Product codes
AT91SAM9N12-EK
751
SAM9N12/SAM9CN11/SAM9CN12 [DATASHEET]
11063K–ATARM–05-Nov-13
40.
Universal Synchronous Asynchronous Receiver Transceiver (USART)
40.1
Description
The Universal Synchronous Asynchronous Receiver Transceiver (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.
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, LIN, and SPI 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.
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 DMA Controller, which enables data transfers to the transmitter and from
the receiver. The DMAC provides chained buffer management without any intervention of the processor.
the receiver. The DMAC provides chained buffer management without any intervention of the processor.
40.2
Embedded Characteristics
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
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
Optional Hardware Handshaking RTS-CTS
Receiver Time-out and Transmitter Timeguard
Optional Multidrop Mode with Address Generation and Detection
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
SPI Mode
Master or Slave
Serial Clock Programmable Phase and Polarity
SPI Serial Clock (SCK) Frequency up to Internal Clock Frequency MCK/6
LIN Mode
Compliant with LIN 1.3 and LIN 2.0 specifications
Master or Slave
Processing of frames with up to 256 data bytes
Response Data length can be configurable or defined automatically by the Identifier
Self synchronization in Slave node configuration
Automatic processing and verification of the “Synch Break” and the “Synch Field”
The “Synch Break” is detected even if it is partially superimposed with a data byte
Automatic Identifier parity calculation/sending and verification