How to use Autonomous mode with STM32WBA55 (USART2 with GPDMA)?

[ledi7]

Hello,

I am using a STM32WBA55 controller and want to wake up from sleep mode (STOP1) as soon as an external interrupt (UART start bit) with falling edge occurs on pin PA11 (PA11 is also the USART2 Rx pin).

Is there a possibility (e.g. with USART autonomous mode) to wake up with falling edge (UART start bit) to start UART with GPDMA or do I have to configure PA11 as external interrupt pin first:

1.) Configure PA11 as external interrupt pin

2) As soon as an interrupt occurs, initialize UART2 and receive a few bytes

3) When the UART2 communication is finished, de-initialize UART2 and initialize PA11 as external interrupt pin again

4) Go into STOP1 mode

[STTwo-32]

Hello @ledi7 

As I've told you on an earlier post, you can use the Receive data register not empty RXNE interrupt to wake up from stop mode. After that, you should read the received data and get back to stop mode.  

Best Regards.

STTwo-32

[ledi7]

Hello @STTwo-32 ,

thanks for your answer!

This is an alternative solution, but this is not the actual “USART Autonomous Mode”!
The USART2 Autonomous Mode uses GPDMA to receive data without CPU interaction.

My question is how to set up this mode or if there is a tutorial for it.