OK, it is the Vref voltage of the loop that is controlled. So the PIC is not in the output voltage loop.

OK, it has some cons, but with a high resolution DAC it will work just fine.

In fact I ordered a couple of MAX5541, 16bit DACs to play with the idea and build a digital controled Power Supply. One for the voltage and the other for he current.

My dream I had from childhood...

Ioannis