This is related to the previous post… What about if you directly hook up a 1.5 volt battery to the ADC in. On my multimeter it say that the battery is about 1.358 and but my ADC says it’s 1.406. I’m using 14 bits of resolution so it should be pretty accurate, about .2 mV.
try doing it against a known load, say 1K between + and - terminals, for both cases. Your meter probably draws more than the ADC.
Does anyone know what the following means exactly:
16 bit value of the ADC in offset binary format.
Note that the ADC is “bipolar”, which means the GND (0V) level is mid-scale.