Arduino for STM32

Official ST low power library:
https://github.com/stm32duino/STM32LowPower
All low power modes are explained there also.
The most power efficient mode without loosing RAM is deepsleep.

Bambo wrote: ↑Wed May 20, 2020 10:47 am Ok so i've added the setClockSource() to the RTC code but now it doesn't restart at all once shutdown is called?

"rtc.setClockSource(STM32RTC::LSE_CLOCK); " needs to be called before rtc.begin();
all about rtc library:
https://github.com/stm32duino/STM32RTC

It's just source for RTC, nothing else.
Don't know what board you're using, but with blue pills I found built-in RTC unreliable, probably due to bad quality oscillators.

You need to set RTC source to LSE if you want it to work in shutdown mode or without power (just with RTC battery).

It all depends on what peripherals you have enabled as each one of them uses power if enabled.
I get from about 30 to 50mA (with 1.3" OLED).

I've attached page from stm32f103x8 datasheet with graphs showing current consumption.
each LED on blue pill board uses about 2mA.