STM32WB Advertising Works Only in Debug Mode (Fails After Power Cycle) on Custom Board

[Anna3]

Hi everyone,

I'm working with a custom board based on the STM32WB55, and I'm facing a very strange issue with the Bluetooth Low Energy advertising. BLE advertising works perfectly when the board is running under debugger (SWD debug mode), wireless stack is correctly updated and option Bytes remain as programmed even after power cycling. CPU2 starts, and aci_gap_set_discoverables() returns BLE_STATUS_SUCCESS.

The problem is, when I remove the debugger and simply power-cycle the board (i.e. unplug power supply usb cable and replug it), BLE advertising does NOT start.

Do you have any idea of how to fix this problem?

Thank you

[B-Mar · Accepted solution]

STM is fun isn't it? So user friendly.

I would check your DEBUG and LPM settings in app_config.h 

By default DEBUG mode will keep the device awake. If low power mode is enabled it will automatically go into it's lowest possible power mode unless told otherwise.

Good luck