As the desire to provide feedback from the power supply on what it is actually doing as well as what it has been commanded to do has always been present, I designed into the board the necessary connectors, voltage dividers and op amps to connect and condition the voltage from the output posts. With the board correctly configured, it is a simple task to configure and turn on the ADC and read the results.

There are 3 ADC channels in use, AN0, AN4 and AN5. AN0 is used for the thermistor used for case temperature sensing, AN4 is the voltage between the positive post and ground, and AN5 measures the voltage drop between across the current sense resistor. By using auto-sample, auto-convert and auto scanning, I can get an interrupt every 3 conversions and get all three values at once.

I have not decided yet as to the best form of filtering to apply, but it is very necessary. I have tried a mathematical low pass filter, and that helped but has made the response a little slow. I may try a boxcar (moving average) filter and see if that improves the situation.

I have found an issue with the voltage reading in that it appears to "top out" at about 19-20v, I will have to change the voltage divider so that this does not happen and the readout can measure the entire range.

Once I have the filter and voltage divider sorted, I will determine the equation of the line that is described, and in turn be able to convert the raw ADC values to voltages.