Mon Apr 28 16:09:51 EDT 2014

I want a digitally programmable voltage and current source

Basically, a voltage source is just a DAC.  A current source is a DAC
+ opamp + transistor.  Current source needs not be very high, so
simple NPN should be good, otherwise use FET.

What uC has a usable DAC?

You know, this is a nice app for Staapl.  Using a digital feedback
loop, pwm can be used to drive the current sources.