I'm using a PICKit board connected via the header to a solderless
breadboard.  I right now have only RC2, power, and ground connected.
RC2 goes to an input of a 7404 inverter, the output of which is
connected via a 100-ohm resistor to a LED.

Things were working fine for about an hour of testing when at some point
the PIC died.  I tried programming it with a known-working program,
still broken.  I replaced it with an identical PIC and programmed that
with the same program and it worked.

What worries me is I have no idea what I did to break the first one.  I
had assumed that it's safe to have a PIC pin drive a TTL input, and it
was working fine for a while.  The only reason I can think of is that
maybe the 7404 plus the LED took too much current and made the PIC
brown-out, but I wouldn't expect that to permanently damage it.

Any suggestions or even speculation would be appreciated, I'm completely
stumped.  I would go on testing with the new one to find out if it was
just a shaky PIC to begin with, but I only have a few so I'd rather
avoid risking the remaining ones if possible :).

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