I'm using a 16F628A which I believe should run as low as 2 volts. It works just fine from batteries providing just under 6 volts but not from 3 volts. The setup is a simple button to INT that triggers an LED to blink. Bypassing the chip and powering the LED (though the resistor) lights up the LED just fine. I figured maybe the battery didn't have enough juice, so I connected the circuit to a line power supply set at 3 volts and it didn't work. Me thinks I'm missing something here...

Thanks,
Tom