Arduino for STM32

Note that the measure is done on IDD. So only the MCU consumption is measured.

Hi, deepsleep (stop mode) works as expected. I've tested with a Nucleo F401RE, I've got something close to your value (3 mA when the LED is OFF). Anyway, you probably have to ensure all unused pins are set to Analog Input and the respective GPIO port clock disabled. The library can't do that for you...

This is a known issue and fixed in the repo. You can find a workaround in the related issue.
https://github.com/stm32duino/Arduino_C ... /pull/2294

In fact you simply can change the HSE_VALUE to the one you have, then the clock config will be inline. You can define it to the variant_*.h or adding a hal_conf_extra.h file with the correct definition. Even in Cube IDE you can change this value thanks cubeMX. Default HSE_VALUE is simply a recommend...

You can optimize several things as explained in the wiki.
About code, I talk about the variant and the update you made else can't help on the clock issue. Some hardware info can help also. Like HSE? LSE?....

Hard to help without the code you add.

A Pull Request on GitHub.

You can find here how to declate the generic:
https://github.com/stm32duino/Arduino_C ... 28board%29

Feel free to submit a PR

Not necessarily as it works fine on nucleo board with same mcu.

Are you sure you used USART3? (Which pins?)
You could read the Errata Sheet, they are some point around UART, ex: Data corruption due to noisy receive line.