STM32WBA55 How to wake-up with USART2 event in stop mode

[ledi7]

Hi,

i am using STM32WBA55 with BLE_p2pServer_ota example and want to wake-up over an USART2 event (start bit or rising edge) from stop mode. What is a good way to do this? I am using HSI16 with USART2 GPDMA1.

[STTwo-32]

Hello @ledi7 

You can use some of the USART2 interrupts to wake up the STM32WBA55 from STOP mode. To do that, you need to configure one of the interrupts that wake up from this low power mode. More details are available on the RM0493 parts 39.6 and 39.7. 

Best regards.

STTwo-32

[ledi7]

Hello @STTwo-32 ,

Thanks for the advice, but what I really want to know is what is the best way to wake up from stop mode by an event on the USART2 interface (Rx pin PA11) to process the USART-Rx data.

Is it good to do the following steps?

1. init PA11 as GPIO_EXTI11 with rising edge
2. as soon as a rising edge on PA11 triggers the interrupt -> Init USART2 and receive Rx data.
3. as soon all data are received -> Init PA11 as GPIO_EXTI11 with rising edge and de-init USART2
4. enter stop mode

Or are there other, better options, e.g. USART2-Rx wake-up with start bit?