"Latch up" means something different to electrical engineers.  If the
processor isn't overheated, then it's not "that kind" of latch up.  But,
check for that, anyway.

Most other ideas I have...interrupts shut off...executing a
SLEEP...executing off into space...these should all be handled by the
watchdog.

Unless you get stuck inside the interrupt routine with the watchdog being
reset continuously.  Otherwise, I can't think of anything else.
--=20
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