+ If your 12C508A project uses GPIO.3 (aka Vpp) as a digital A/D input or
otherwise relies on the trigger input levels, and acts erratically,
suspect the pin was subjected to static (ESD) damage. The GPIO.3 pin has
no protection diode to Vdd because it must withstand the programming
voltage. For development purposes add a 15V tranzorb between GPIO.3 and
Vss. Do this in despite of various archived messages complaining about
'unstable' trigger levels on that pin. Once you see erratic behavior
assume it has happened and do not trust the part again.

0.01 Ag.
Peter

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu