Hi,
I am building a Battery Charger and am not sure about
reading the Battery Voltage with the ADC of the F872.
I have it set up in code and if I hook my ADC to
ground I read 0-3 using the 10 bit ADC (0-1023).
If I hook to my supply I read 1021-1023.
So far so good. I have the 8xAA battery pack grounded
to my protoboard with a 2k Resistor and 1k Resistor
in serires tied between V+ and GND. If I measure
the voltage with my DMM I get 3.5volts, which is
a third of the pack voltage, but if I read the
voltage with my ADC I get 25-27 when I am expecting
to see about 136. Also when I plug the wire of the ADC
in the resistor ladder, the DMM drops from 3.5V to
135millivolts.
Could someone enlighten me as to what I am doing wrong.
I have seen this simple circuit on a number of chargers.

Thanks,
Kevin

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