F407 wake-up error

[tglim]

I have a question regarding an F407 wake-up error.

I am using an F407ZGT and have connected the power switch to PA0 using a pull-down resistor.

HAL_SuspendTick();
HAL_PWR_EnableWakeUpPin( PWR_WAKEUP_PIN1 );
__HAL_PWR_CLEAR_FLAG( PWR_FLAG_WU | PWR_FLAG_SB );
HAL_PWR_EnterSTANDBYMode();

I have been using this code successfully.

However, after modifying the firmware and downloading it, or when downloading via the gang tool, the MCU fails to wake up via the wake-up input—though not always. Once this issue occurs on a board, the wake-up function permanently stops working, regardless of any operations performed.

Is there any way to restore the wake-up function?

Please help me!

[FBL]

Hello @tglim 

Make sure to disable all used wakeup sources first. Did you verify the PA0 external signal using logic analyzer?

[Andrew Neil]

---

@FBL wrote:

Make sure to disable all used wakeup sources first.

---

@tglim  Indeed - as shown in the CubeF4 examples; eg,

/**
  * @brief  This function configures the system to enter Standby mode for
  *         current consumption measurement purpose.
  *         STANDBY Mode
  *         ============
  *           - Backup SRAM and RTC OFF
  *           - IWDG and LSI OFF
  *           - Wakeup using WakeUp Pin (PA.00)
  * @PAram  None
  * @retval None
  */
void StandbyMode_Measure(void)
{
  /* Enable Power Clock*/
  __HAL_RCC_PWR_CLK_ENABLE();

  /* Allow access to Backup */
  HAL_PWR_EnableBkUpAccess();

  /* Reset RTC Domain */
  __HAL_RCC_BACKUPRESET_FORCE();
  __HAL_RCC_BACKUPRESET_RELEASE();

  /* Disable all used wakeup sources: Pin1(PA.0) */
  HAL_PWR_DisableWakeUpPin(PWR_WAKEUP_PIN1);

  /* Clear all related wakeup flags */
  __HAL_PWR_CLEAR_FLAG(PWR_FLAG_WU);

  /* Re-enable all used wakeup sources: Pin1(PA.0) */
  HAL_PWR_EnableWakeUpPin(PWR_WAKEUP_PIN1);

  /*## Enter Standby Mode ####################################################*/
  /* Request to enter STANDBY mode  */
  HAL_PWR_EnterSTANDBYMode();
}

https://github.com/STMicroelectronics/STM32CubeF4/tree/master/Projects/STM32F401RE-Nucleo/Examples/PWR/PWR_CurrentConsumption