It works!

I can now set the voltage and current through the serial and it actually sets the output to the right value (haven't validated current limit yet).

I needed to do proper calculation of the PWM values and for that there was a roadblock with integer overflows in the fixed point calculations. The initial setup for the current and voltage control was reversed.

I also had a roadblock where out of the two units I have both have some issue now with the top board, one doesn't display properly and the other can't control the output properly.