Hi,

If you are using a VCO then you might use a few more pins on the PIC to shift the voltage level on both ends of the POT. Your options are high = 5 volts, low = 0 volts and input = HighZ.

In this way you would increase the resolution of the whole thing.So your software would control the voltage ranges between say,

0v to 1v
1v to 2v
3v to 4v
4v to 5v

and you get 256 steps on each. Since it is a self oscillator you can feed the osillator signal back to the PIC and make a dynamic calibration routine for drifts in your ladder DA circuit + POT.


Wishing a speedy recovery to our forum member steve who is hurt in a car accident.

Best Regards
Sougata