I am looking for a way to monitor mDot power supply when voltage goes below 3V. CPU and radio can still work in that condition, but I can not find the way to know what is happening with voltage. If I use an ADC input with resistor divider, when the onboard regulator stops working I get wrong readings.
I have found in another topic that both VBAT and VDDA of STM32F411 are connected to the output of the regulator. I guess VREF+ and VREF- are connected to VDDA and VSSA respectively. So I think will not find the solution there.
Is there a way to use an internal reference for the ADC? If so, can you provide an mbed example?
Same question for xDot.