SHIFTOUT is not working


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  1. #1
    Join Date
    Jul 2009
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    Default

    UPDATE:

    PROBLEM SOLVED!

    In case anyone else has the problem I did - i.e. SHIFTOUT not generating any signals, here is how I solved it:

    I should have followed the three standard debugging rules when it comes to odd behaviour in PICs:

    1. Check the MCLR pin isn't held low (it wasn't)
    2. Check there is a clock signal (there was)
    3. Check the CONFIG bits - HERES THE PROBLEM!

    I went through all of the CONFIG options and discovered that with Extended Instruction Set enabled SHIFTOUT did not work, but as soon as it was disabled everything worked as expected!

    I guess the simulation doesn't differentiate between extended and non-extended and just works in either case.

    Hope this helps anyone who has the same problem.

  2. #2
    Join Date
    Jan 2005
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    France
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    Default ****out problem

    Thanks for your message, but what do you mean by " Extended Instruction " ?

    bye the way, I have a problem, not the same but ...

    I try to use also the SHIFTOUT command to send data to a PLL (via Clock and Data pins)
    I use the mode (1 or 5) but the clock is always at HIGH level and there is just a DOWN pulse
    From the help explanation (clock idles high or low) my understanding was
    clock idles low .... clock signal is at LOW level and a positive pulse occur
    clock idles High ... clock signal is at HIGH level and a négative pulse occur
    as I said I try mode 1 or 5, and I see NO difference on the oscilloscope !

    any idea ?

    thanks
    Francois


    Quote Originally Posted by awmt102 View Post
    UPDATE:

    PROBLEM SOLVED!

    In case anyone else has the problem I did - i.e. SHIFTOUT not generating any signals, here is how I solved it:

    I should have followed the three standard debugging rules when it comes to odd behaviour in PICs:

    1. Check the MCLR pin isn't held low (it wasn't)
    2. Check there is a clock signal (there was)
    3. Check the CONFIG bits - HERES THE PROBLEM!

    I went through all of the CONFIG options and discovered that with Extended Instruction Set enabled SHIFTOUT did not work, but as soon as it was disabled everything worked as expected!

    I guess the simulation doesn't differentiate between extended and non-extended and just works in either case.

    Hope this helps anyone who has the same problem.

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