Thread: PIC16F877 not executing?
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Unread 11-06-2008, 18:01
MCahoon MCahoon is offline
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Re: PIC16F877 not executing?
My experience has been similar to Jason's, such that I always put about a 22K pullup on the MCLR. I can't say I've observed a MCLR error, since I don't have access to an In Circuit Debugger (I use a PICKIT 2 ICSP, but the chips I use don't support the debug feature).

The other thing I've noted is to make sure you disable the low voltage programming, else almost any noise on the PGM pin will tend to interrupt the program and cause the device to attempt to go into a programming mode. My quick test for this is if the chip

At last, but I feel most likely, try connecting a 1 microfarad capacitor (I use a ceramic non-polarized) between power and ground fairly close to the power pins on the chip. I have had a number of PIC designs which would run off the power supply provided by the ICSP, but when connected to a 5 V power supply they would simply stop. The capacitor always corrected that.