> Without looking at any data sheets  ...
> 
> It's traditionally O/C to allow programming voltage > Vdd to be
> applied to the programming system which shares a pin with RA4

I don't recall any PICs using RA4 for programming. I think all the
ones I've ever used, from 10F up, have Vpp on /MCLR, which is
often RE3 on larger PICs, like Josh's 18Fxx21, with PGC and PGD
on the usual RB6, RB7
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist