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