open drain output as digital output?


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  1. #1
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    Default open drain output as digital output?

    Will a port pin that is an "open drain output" support a SEROUT command?
    The pin in question RA4 is multiplexed with a Timer0 module clock input. Can it still be used as a digital pin?

    Will a SEROUT command set the pin digital output even if the pin was previously set as analog input?
    Last edited by droptail; - 8th November 2006 at 05:17.
    James

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    Sure this does not apply generally to all Pics. Can you specify the device you talk about?

    Jerson

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    Microchip PIC16C716
    James

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    droptail, just use a pullup resistor of about 2.7k to 4.7k.

    Dave Purola,
    N8NTA

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    Will a port pin that is an "open drain output" support a SEROUT command?
    Yes for sure, use Dave's suggestion.

    The pin in question RA4 is multiplexed with a Timer0 module clock input. Can it still be used as a digital pin?
    Yes

    Will a SEROUT command set the pin digital output even if the pin was previously set as analog input?
    Nope, this is also why we see many question about that. Always make sure you disable multiplexed stuff(when possible) on an i/o before using it.

    ADCs/analog comparator are popular.
    Steve

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

  6. #6
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    I have success with 1k hold up for now.
    I also have no problems for years with SEROUT command working on a port pin set as analog and input, why?

    TRISA =255 'all PortA Inputs
    ADCON1 =0 'all PortA Analog

    SerOut PORTA.0,N2400 ...
    James

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    Thank you both for your help.
    James

  8. #8
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    Probably at slow baudrate it may work... but i will never trust or use that.
    Steve

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

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