Hi Reg,

Reginald Neale wrote:

>   Does the PIC drive any kind of load other than LEDs? If so, can you
>   temporarily disconnect them to see if that has any effect?

No, only LEDs. I use 4 on Port B and 3 on Port A, maximum of 2 on at any
time. I've got a 0.1uF cap directly between Vdd and Vss.

>   What about unused pins? Do you have any, how are they treated in
>   software, and are they terminated?

No unused pins. Actually, I use the internal pull-up and change on pin int to
check when a switch opens on Portb 4-7. Maybe there is something strange with
the pullups drawing too much current?
Thanks!
Graham.