No serial output after first wake from deepsleep

[miroslavpetrov]

Describe the bug
Using the unmodified example AlarmTimedWakeup.ino from the library and Seeed Lora-E5 Mini board, after the first wake up from deepsleep there is no output on the serial console.

To Reproduce
Upload AlarmTimedWakeup example to the board.

Expected behavior
I expect the serial port to continue working after wake up

Desktop (please complete the following information):

• OS: Mac OS Sonoma 14.5

• Arduino IDE version: 2.3.2

• STM32 core version: 2.8.0

• Library version: 1.2.5

• Tools menu settings if not the default: Core logs enabled, Optimize: smallest, Runtime Newlib nano, UART: Enabled(generic serial), Board part number - Lora-E5 mini

• Upload method: manual export compiled binary and drag and drop to STLink drive

Hardware (please complete the following information):

• Board Name: Seeed Wio-E5 Mini based on STM32wle5jc
• Hardware Revision: v1.0

[miroslavpetrov]

@fpistm any ideas?

[fpistm]

No. I will check when I will have some time.

[fpistm]

Hi @miroslavpetrov
I've reproduced and try to debug deeply but hard with this series as debug with low power mode is a nightmare (several issue document in the errata sheet).
In the case of STM32WL, the deepsleep rely on STOP 2 mode and so it requires to properly init the Serial after the deepsleep.