Quote Originally Posted by BrianT View Post
Low Voltage.
I suggest you very carefully experiment and verify what your PIC will do with a 1.5 volt supply. The datasheets are silent about such operation. I had a bunch of data loggers where the 3.7 volt battery went completely flat and the processor code was all erased - not scrambled - erased.

Hmm.... that's disturbing. Anyone else have that happen?

I can't imagine they'd design a pic that would zap itself just from a dead battery - I'd imagine all kinds of electronics "dying" all of a sudden just becase a battery went dead, but I guess anything is possible.

Is the idea then to make sure and power the pic *all the way* down - zero volts, power rail tied to ground? That seems a bit extreme to make sure it's totally de-powered, but maybe it's a good idea. I'd expect there are thousands of devices out there where the pic sees some residual voltage from a capacitor or something.

We're going to run a batch of quite a few of these things where the design will be hard to change after the fact, so if they do start to die due to the low voltage, it'll be a major problem to fix them.