Datasheet

Functional overview STM32L031x4/6
32/126 DS10668 Rev 6
3.16.2 Universal synchronous/asynchronous receiver transmitter (USART)
The USART interface (USART2) is able to communicate at speeds of up to 4 Mbit/s.
it provides hardware management of the CTS, RTS and RS485 driver enable (DE) signals,
multiprocessor communication mode, master synchronous communication and single-wire
half-duplex communication mode. USART2 also supports Smartcard communication (ISO
7816), IrDA SIR ENDEC, LIN Master/Slave capability, auto baud rate feature and has a
clock domain independent from the CPU clock that allows to wake up the MCU from Stop
mode using baudrates up to 42 Kbaud.
USART2 interface can be served by the DMA controller.
Table 12 for the supported modes and features of USART interface.
3.16.3 Low-power universal asynchronous receiver transmitter (LPUART)
The devices embed one Low-power UART. The LPUART supports asynchronous serial
communication with minimum power consumption. It supports half duplex single wire
communication and modem operations (CTS/RTS). It allows multiprocessor
communication.
The LPUART has a clock domain independent from the CPU clock, and can wake up the
system from Stop mode using baudrates up to 46 Kbaud. The Wakeup events from Stop
mode are programmable and can be:
• Start bit detection
• Or any received data frame
• Or a specific programmed data frame
Only a 32.768 kHz clock (LSE) is needed to allow LPUART communication up to 9600
baud. Therefore, even in Stop mode, the LPUART can wait for an incoming frame while
Table 12. USART implementation
USART modes/features
(1)
1. X = supported.
USART2
Hardware flow control for modem X
Continuous communication using DMA X
Multiprocessor communication X
Synchronous mode
(2)
2. This mode allows using the USART as an SPI master.
X
Smartcard mode X
Single-wire half-duplex communication X
IrDA SIR ENDEC block X
LIN mode X
Dual clock domain and wakeup from Stop mode X
Receiver timeout interrupt X
Modbus communication X
Auto baud rate detection (4 modes) X
Driver Enable X
Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.