GD32A50x User Manual
469
19.
Universal
synchronous/asynchronous
receiver
/transmitter (USART)
19.1.
Overview
The Universal Synchronous/Asynchronous Receiver/Transmitter (USART) provides a flexible
serial data exchange interface. Data frames can be transferred in full duplex or half duplex
mode, synchronously or asynchronously through this interface. A programmable baud rate
generator divides the UCLK (PCLK, CK_SYS, LXTAL or IRC16M) to produces a dedicated
wide range baudrate clock for the USART transmitter and receiver.
Besides the standard asynchronous receiver and transmitter mode, the USART implements
several other types of serial data exchange modes, such as IrDA (infrared data association)
SIR mode, smartcard mode, LIN (local interconnection network) mode, half-duplex mode and
synchronous mode. It also supports multiprocessor communication mode, and hardware flow
control protocol (CTS/RTS). The data frame can be transferred from LSB or MSB bit. The
polarity of the TX/RX pins can be configured independently and flexibly.
All USARTs support DMA function for high-speed data communication.
19.2.
Characteristics
NRZ standard format
Asynchronous, full duplex communication
Half duplex single wire communications
Receive FIFO function
Dual clock domain:
–
Asynchronous PCLK and USART clock
–
Baud rate programming independent from the PCLK reprogramming
Programmable baud-rate generator allowing speed up to 12.5 MBits/s when the clock
frequency is 100 MHz and oversampling is by 8
Fully programmable serial interface characteristics:
–
A data word (8 or 9 bits) LSB or MSB first
–
Even, odd or no-parity bit generation/detection
–
0.5, 1, 1.5 or 2 stop bit generation
Swappable TX/RX pin
Configurable data polarity
Hardware Modem operations (CTS/RTS) and RS485 drive enable
Configurable multibuffer communication using centralized DMA
Separate enable bits for Transmitter and Receiver
Parity control