Quote Originally Posted by Melanie
If you truely have filtered, noisless input on your ADC pin like you say...

As a start, increase your Sample Time and/or change your Clock Source. It's a good possibility that you are not letting the sampling Capacitor enough time to charge properly before you take your reading.

It's also a possibility you have set the wrong Justification for a WORD variable. Double-check this also.
Vdd is filtered by 4700uF and I got 12V/7.2Ah battery to feed +5V regulator -> power supply should be ok.

The input voltage should be stable since there are 10k resistor + 4700uF + 220nF capasitors in parallel (connected ANx -> Gnd) and there is 10-turn 10k potentiometer from Anx -> +5V, should make it steady enough - at least it looks that way in my scope.. I dunno..

ADCS is 010 (Fosc/32) - should be ok?

Increasing sampling time has unwanted, negative influence into responce time.. ok, I did increase sampling time up to 300uS and it did help quite a lot - still the measurement is jumpy, 508..516... that is best I can get out of it?

I will rewire all ground lines and let's see if that helps.

Thnx, if u have any ideas, please let me know!