Datasheet

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STM32L452xx Functional overview
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3.26 Universal synchronous/asynchronous receiver transmitter
(USART)
The STM32L452xx devices have three embedded universal synchronous receiver
transmitters (USART1, USART2 and USART3) and one universal asynchronous receiver
transmitters (UART4).
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=1,2,3,4) 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 13. STM32L452xx USART/UART/LPUART features
USART modes/features
(1)
USART1 USART2 USART3 UART4 LPUART1
Hardware flow control for modem XXXX X
Continuous communication using DMA XXXX X
Multiprocessor communication XXXX X
Synchronous mode X X X - -
Smartcard mode X X X - -
Single-wire half-duplex communication XXXX X
IrDA SIR ENDEC block XXXX -
LIN mode XXXX -
Dual clock domain XXXX X
Wakeup from Stop 0 / Stop 1 modes XXXX X
Wakeup from Stop 2 mode ---- X
Receiver timeout interrupt XXXX -
Modbus communication XXXX -
Auto baud rate detection X (4 modes) -
Driver Enable XXXX X
LPUART/USART data length 7, 8 and 9 bits
1. X = supported.
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