You can use POT on PIC's with no ADC's (like F84 or F628 etc) which makes it useful in some situations.

I've found that you have to play with the POT scale settings sometimes, as it doesn't quite follow the manual. I've had a situation (10K pot and 100nF capacitor) where using the recommended scale of 127 as a starting point (see manual) did not return meaningful results in Var (always zero I recall), and only when scale was reduced to around 100 did things start to work as expected.

This is one of those experiment and see situations.

Just as a reminder for everyone else reading this thread... never use the open drain pin on the PIC (PortA.4 I believe).