Ahhh,

18F1320 ...

I had reprogramming problems with some of them ( still have one which definitly "locked" after ~ 20 reprogrammings ) Thread posted here.

The second one took service back two Picstart plus revisions later...

Batch is 05250SE ...

Tried three programmers : Picstart+, ICD2 and a ( trustable ) "custom one" ... same behaviour.


Microchip never answered anything about that ...

Soooo, I'd encourage you to turn to another pin for pin compatible chip ( 16F88 i.e. ... )

Alain