Hi earltyso,
You cannot use the Vcc from your PCB in place of the Vpp needed for ICSP.
Vpp is some voltage higher than Vcc something like 12.5 or 13.5 V DC.
The MCLR pin must be free to snap to Vpp voltage to program ICSP. and then it must be “pulled high” (to Vcc not Vpp) to run the program.
That is what Dave meant by a “protection diode” or his jumper idea.
The MCLR pin must be free of any circuit that slows it down.
Great ideas on ICSP PICs: http://www.embedinc.com/picprg/icsp.htm
(Some suggest a 1K pull-down between MCLR and ground for programming.)
Dave is right, get it working on a breadboard before you commit to a PCB!
-Adam-
Ohm it's not just a good idea... it's the LAW !
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