Error amps ground reference offset

[prasimix]

It's possible that calibrated 0 V or 0 A will require negative DAC output (U_SET or I_SET value). Since DAC has not bipolar output signal it's possible that we cannot get the whole range starting from zero. For people that wants that output value can be programmed down to zero, ground for IC 6B and IC 8A could be shifted for e.g. 100 mV. That be accomplished in some of the next PCB revision with IC 7B that is not used in r5B9 and voltage divider connected to +VREF.