Problems with 18F458


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  1. #1
    Join Date
    Sep 2004
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    Tallinn, Estonia
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    May-be your clock speed is too high? PLL ON perhaps?
    Try simulating your code in MPLAB. If this works OK, it's something in hardware. If not, you'll find the bug quickly.

  2. #2


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    I was just looking at your picture an couldn't help but notice the leads coming for the crystal. Shouldn't there be a empty space in between the pins. It looks like the pins are spaced at 0.100". It might be just the picture but I think the crystal is actually 0.200" pin spacing.

  3. #3
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    Sep 2004
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    montreal, canada
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    My 2 cents... the crystal is really to far of the PIC, and try to remove both capacitor... breadboard capacitance
    Steve

    It's not a bug, it's a random feature.
    There's no problem, only learning opportunities.

  4. #4


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    I actually found running 22pF with our PIC's caused us loads of troubles. Things would reset all the time, corrupt displays and sensors. Removed the capacitors and everything works fantastic now. Scope the ocsillator output and noticed the capacitors were actually causing a lot of noise.

  5. #5
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    100ms delay before you initialize your display could be too short. Many displays needs alot more. Try a couple of seconds and see if that makes it work.

  6. #6
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    Aug 2005
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    Unhappy

    No, I tried everything, removed the caps, set the most of the conf. bits to be negative, moved the osc. closer, increased the init delay (though it has worked well with 100 with the same display but a PIC16F84)....nothing helps, it still writes "!" in the start of the first line instead of the "Hello world!"

  7. #7
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    Aug 2005
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    Btw. here is a picture of my cfg.
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