Quote Originally Posted by Aussie Barry View Post
Darrel, can you please explain how you arrived at the value 117 for the Vref_AD constant? I would have expected it to be 0.6/5*1023 = 122
The internal fixed references are not very accurate, so you have to read the actual value to determine the number to use.

For my project I was able to use another ADC pin to monitor the supply voltage so all is good (for the time being).
Thats a bit like lifting yourself up by your own bootstraps.