Datasheet

Functional overview STM32L431xx
42/200 DocID028800 Rev 1
3.25 Universal synchronous/asynchronous receiver transmitter
(USART)
The STM32L431xx devices have three embedded universal synchronous receiver
transmitters (USART1, USART2 and USART3).
These interfaces provide asynchronous communication, IrDA SIR ENDEC support,
multiprocessor communication mode, single-wire half-duplex communication mode and
have LIN Master/Slave capability. They provide hardware management of the CTS and RTS
signals, and RS485 Driver Enable. They are able to communicate at speeds of up to
10Mbit/s.
USART1, USART2 and USART3 also provide Smart Card mode (ISO 7816 compliant) and
SPI-like communication capability.
All USART have a clock domain independent from the CPU clock, allowing the USARTx
(x=1,2,3) to wake up the MCU from Stop mode using baudrates up to 200
Kbaud. The wake
up events from Stop mode are programmable and can be:
Start bit detection
Any received data frame
A specific programmed data frame
All USART interfaces can be served by the DMA controller.
Table 11. STM32L431xx USART/LPUART features
USART modes/features
(1)
1. X = supported.
USART1 USART2 USART3 LPUART1
Hardware flow control for modem X X X X
Continuous communication using DMA X X X X
Multiprocessor communication X X X X
Synchronous mode X X X -
Smartcard mode X X X -
Single-wire half-duplex communication X X X X
IrDA SIR ENDEC block X X X -
LIN mode X X X -
Dual clock domain X X X X
Wakeup from Stop 0 / Stop 1 modes X X X X
Wakeup from Stop 2 mode - - - X
Receiver timeout interrupt X X X -
Modbus communication X X X -
Auto baud rate detection X (4 modes) -
Driver Enable X X X X
LPUART/USART data length 7, 8 and 9 bits
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