I picked up the parts last week, and over the weekend I wired up a single channel (positive, using an NPN transistor) on the breadboard. Despite a couple false starts due to bad components (most notably the current limiting transistor, an old N2222 from my parts bin, caused all sorts of troubles before completely shorting out and exploding), it is now working. So far it only uses pots for V_SET and I_SET, the next step is to integrate the MCU.

I have done very little testing so far, but what I have seen looks promising. More info to come as it is available.

Along with the breadboarding comes some new design points:

• The interface for each channel is now purely analog (with values from 0 - 5V); the DACs are no longer on each channel. This allows for less wastage (all DAC channels are fully utilized), as well as giving an option for those people who don't want a dedicated controller board - simply use a potentiometer for VSET / ISET, and use your multimeter to read actual voltage / current outputs.
• Use a dedicated controller board with space for all DAC instead of re-using a 32u4 breakout board. This will make for easier wiring within the case (much fewer cables running all over the place).
• USB header is now on a separate board to allow for positioning in different arrangements within the case.

An updated schematic is below.

Cheers