Datasheet
DocID028798 Rev 3 43/155
STM32L432KB STM32L432KC Functional overview
49
3.24 Universal synchronous/asynchronous receiver transmitter
(USART)
The STM32L432xx devices have two embedded universal synchronous receiver
transmitters (USART1 and USART2).
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 and USART2 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) to wake up the MCU from Stop mode using baudrates up to 204
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. STM32L432xx USART/LPUART features
USART modes/features
(1)
1. X = supported.
USART1 USART2 LPUART1
Hardware flow control for modem X X X
Continuous communication using DMA X X X
Multiprocessor communication X X X
Synchronous mode X X -
Smartcard mode X X -
Single-wire half-duplex communication X X X
IrDA SIR ENDEC block X X -
LIN mode X X -
Dual clock domain X X X
Wakeup from Stop 0 / Stop 1 modes X X X
Wakeup from Stop 2 mode - - X
Receiver timeout interrupt X X -
Modbus communication X X -
Auto baud rate detection X (4 modes) -
Driver Enable X X X
LPUART/USART data length 7, 8 and 9 bits
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