Figure 331. Wake-Up Event Verified (Wake-Up Event = Address Match, Fifo Disabled); Figure 332. Wake-Up Event Not Verified; Fifo Disabled) - STMicroelectronics STM32WL5 Series Reference Manual

Universal synchronous/asynchronous receiver transmitter (USART/UART)
Figure 331

Figure 331. Wake-up event verified (wake-up event = address match, FIFO disabled)

usart_ker_ck
Figure 332
Figure 332. Wake-up event not verified (wake-up event = address match,
usart_ker_ck
Note: The figures above are valid when address match or any received frame is used as wake-up
event. If the wake-up event is the start bit detection, the USART sends the wake-up event to
the MCU at the end of the start bit.
1162/1450
shows the USART behavior when the wake-up event is verified.
Idle
RX line
Startup time
OFF
Low-power mode
shows the USART behavior when the wake-up event is not verified.
Idle
RX line
Startup time
OFF
Address match event WUF ='1'
USART sends a wakeup event to the MCU
Rx data 1
ON

FIFO disabled)

Address does not match
Rx data 1
ON
Low-power mode
RM0453 Rev 5
Data reception goes on
Rx data 2
Run mode
Idle
OFF
RM0453
MSv40856V2
MSv40857V2