I was working with the Robostix today, and using the General I/O pins.  When I set the I/O pin to 1, and use it across a 2k ohm and 1k ohm resistor, to drop the VDD to 2.7V, the I/O pin voltage drops from 3.9V to 0.3V .  ANy idea why this would happen, and how we can get around this problem?  It seems that any load on that pin drops the voltage down.