As a hobbyist, my range if PIC's is currently quite limited. 16F876, 877
etc and a couple of the 18F parts.

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Now I've got a programmer that can program all these parts but I'm
getting confused on the project side and the MCLR.

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When I build a project, I always add a 4 pin ICP connector. One pin
ground, VPP to the MCLR pin, Data and Clock. I tie the MCLR PIC pin via
a diode and a 1K resistor to +5v allowing the PIN to be pulled high by
the circuit but not allowing the VPP from the programmer to get onto the
projects power bus. I never power my project from the programmer, always
from it's own PSU/5v

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I've looked at several circuits and they all seem different. Some have a
capacitor from the MCLR pin to ground. Some don't have a diode. Some
don't even seem to bother with the resistor and just leave the pin
floating.

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Is there a "proper" way of doing things ?

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Also, my ICP cable is about 2 feet long. There was no real reason for
this, it's just the way it happened.=20

Is this too long ?

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The reason all this has come about is that I have a very simple circuit
with a 16F628 and for the life of me I can't get it to program via the
ICP cable. If I take the PIC out and sit it in the ZIF then it works
fine. I thought it might be some quirk with the PIC but I've tried
several and they all exhibit the same problem - the verification pass
fails.

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Could somebody give me some advice or point me to some documentation
please.

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Thanks,

Joe

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