I have a couple questions: 1 - What frequency is the PIC running at? 2 - Are the DC input leads to the PIC and the 74HC595 adequately bypassed with capacitors? (I'd assume you did this properly). 3 - Are all ground leads on the PIC grounded? I just about went around the bend once trying to figure out why one 16F877 circuit wouldn't work and found I'd forgotten to ground one of the ground leads. It worked fine once I did that. 4 - What is the duration of the pulses from the PIC to the HC595 that you're sending, per your program? Zack On Thu, 7 Sep 2006, oldhat_owen wrote: > I know this is perhaps a bit off topic but I have several boards with > PIC16F877 processors driving an HC595 shift register and the output > pins from the pic driving the HC595 are virtually all glitches. > > It is hard to pick up a high or low as such on the logic analyser > other outputs seem ok, has anyone any idea what may be causing this. > > And yes I do not like pic's I normally use AVR'S. > > Owen. >
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Re: [AVR-Chat] OT HC595 AND PIC GLITCHES
2006-09-07 by Zack Widup
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