Quote Originally Posted by prizepony View Post
I'm having the same issue programming a 16F877 PIC chip.
I'm using MicroCode Studio and EPIC Parallel Port Programmer.

I tried two different programmers and yet both the same issue.

Has there been any new info on this topic?
the length of cable between the DB25 connector and the EPIC programmer matters. while the 7407 (better 74HC07) chip could be powered from the programmer board, it is preferable to shift it in to the body of DB25 connector. Thereafter take only those wires that are needed by the programmer. Thereafter the length of the few wires can also be optimized for proper functioning of the programmer.

Another observation- of course not related to but applicable to PICs as well, is to use a small resistor in series to the clock signal and have a 0.001(1KpF) capacitor to ground (or pin5)at the PIC socket.

Third issue is to have a 0.1uF capacitor across Vdd and Vss across the PIC socket.
With above mods, the programming becomes consistent & easier.