I gather there are no schematics available for the mDot. Bit of a pain trying to reverse engineer everything.
I haven’t been able to get confirmation on what the Vbat pin of the STM32F411 on the mDot is connected to.
According to this thread, it’s connected to a regulated supply.
Why then do I get 3.85V when running powered from the MDK and using the ADC to measure that pin? Measuring Vdda with the same method gives 3.00V, which is what I expect from the information buried in some thread somewhere. So does that mean Vbat’s regulator is 3.85V? Why such an odd voltage, and is anything else supplied by this rail?
Ultimately I’d like to measure the input voltage for battery operation. I suspect I’ll need to wire in an external voltage divider, but just trying to understand what’s already on the board.