Wake up immediately after shutdown in STM32L451

[Yoshi1]

HAL_PWR_EnterSTANDBYMode() will still wait properly, but HAL_PWREx_EnterSHUTDOWNMode() will immediately return to RUN mode.

What do you think is the cause of immediate wakeup?

As shown below, the only code difference is whether to enable HAL_PWREx_EnterSHUTDOWNMode () or HAL_PWR_EnterSTANDBYMode ().

  __HAL_PWR_CLEAR_FLAG(PWR_FLAG_WU);
  __HAL_PWR_CLEAR_FLAG(PWR_FLAG_SB);
  __HAL_RTC_WAKEUPTIMER_CLEAR_FLAG(&hrtc, RTC_FLAG_WUTF);
  while(1)
  {
    HAL_PWREx_EnterSHUTDOWNMode();
//    HAL_PWR_EnterSTANDBYMode();
  }

Best regards,​

[Yoshi1 · Accepted solution]

I solved it myself.

The cause was that nRST_SHDW was unchecked in the option byte.

Best regards,​

[Imen.D]

Hello @則幸 �?�岡​ ,

Really glad to know you overcame this problem.

Thank you for the update you provided.

Thanks

Imen