Board resets systematically from standby mode

[nogema]

Hello,

I would like to reach the lowest consumption as possible. I am programming an end node which sends data through TTN. My project is based on the LoRaWAN End Node example with the LoRaWAN middleware.

My fimrware works like that :

• at boot, the board join to TTN
• after joined, the board turns in low power mode
• if the button on the board is pressed, the board wakes up and sends some datas to TTN
• after received the acknoledge, the board turns in low power mode

The example PWR_STANDBY works without any problem, I reach a consumption of 1.1 µA. I copied the code that configures and turns the board in standby mode into my firmware but at each boot, after reached the function HAL_PWR_EnterSTANDBYMode(), the board resets automatically.

Do you have any idea what I did wrong or miss in my firmware ? I can add the source code if needed.

I am using a custom board with the LoRa E5 STM32WL5EJC module embedded and the STM32WL package.

Thanks you in advance

Regards

[Jorgie]

Is there a generic solution to this for all of the STM32 Family?

I am currently trying to enter SHUTDOWN Mode in an STM32U083 and the processor keeps resetting and starting to run the code from the beginning again.

I'm calling:

HAL_PWR_EnterSHUTDOWNMode

I have added:

PWR->SCR = PWR_SCR_CWUF; // Clear wakeup flags

To the  void HAL_PWR_EnterSHUTDOWNMode(void) function but it is still resetting.