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  • Finding good documentation for gpiod

    From Chris Green@21:1/5 to All on Fri Sep 1 21:48:59 2023
    I am using the gpiod package for manipulating GPIO inputs/outputs on a Beaglebone Black SBC (like a Raspberry Pi but with more flexible I/O).

    Mostly I am managing to get things to work as I want but better
    documentation of gpiod would be a great help.

    For example, when one has found an I/O pin (a 'line' in GPIO parlance)
    that one wants to use one has to 'request' it using the Line.request()
    method.

    The help for this is as follows:-

    Help on method_descriptor:

    request(...)
    request(consumer[, type[, flags[, default_val]]]) -> None

    Request this GPIO line.

    consumer
    Name of the consumer.
    type
    Type of the request.
    flags
    Other configuration flags.
    default_val
    Default value of this line.
    Note: default_vals argument (sequence of default values passed down to
    LineBulk.request()) is still supported for backward compatibility but is
    now deprecated when requesting single lines.


    Which is pretty good **except** that I can't find a proper description
    of the parameters anywhere, i.e. there's nowhere that even tells me
    what types of values/objects the parameters are. At the end of the
    gpiod.Line section of the help there is this:-

    | ACTIVE_HIGH = 1
    |
    | ACTIVE_LOW = 2
    |
    | BIAS_AS_IS = 1
    |
    | BIAS_DISABLE = 2
    |
    | BIAS_PULL_DOWN = 4
    |
    | BIAS_PULL_UP = 3
    |
    | DIRECTION_INPUT = 1
    |
    | DIRECTION_OUTPUT = 2

    Which **might** be appropriate values for 'type' or 'flags' but there
    doesn't seem to be any way of knowing.

    Am I missing something very obvious somewhere? Is there a 'standard'
    way of finding out parameter information?

    It may well be that I'm simply banging up against the limit of what documentation is available, I have managed to get code working OK.
    It's just that I'd be happier if I really know what I was doing! :-)



    --
    Chris Green
    ยท

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  • From Barry@21:1/5 to All on Mon Sep 4 06:22:11 2023
    E

    On 3 Sep 2023, at 22:49, Chris Green via Python-list <python-list@python.org> wrote:

    Mostly I am managing to get things to work as I want but better
    documentation of gpiod would be a great help.

    Ask the author? https://github.com/aswild/python-gpiod

    Maybe read the source code for hints?

    Barry

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