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Discussion in 'Electronic Basics' started by [email protected], Jun 23, 2006.

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  1. Guest

    I'm trying to make an adapter between a parallel port and a device used
    in psych experiments. The port on the device is a 15pin d-sub
    connector (2 rows like an old game port, not 3 like a monitor)

    I know that pins 1-8 on the 15pin connector are the data and that it
    runs on TTL logic levels, but the data is supposed to be "inverted."
    Would that typically mean that a 0 is on and a 1 is off, or would it
    more probably mean that the least-to-most significant bit order is
    flipped from the parallel port?

    Also, in a version sold by the company for $200, the only additional
    feature is that it buffers the data because the port can be both input
    and output. However, if we're only ever using the input function of
    the port it shouldn't require a data buffer, correct?

    I can't really see paying $200 for a part that seems to just be an
    adapater between two connector types and even in the picture on their
    website looks like it's just electrical-taped or heatshrinked together.

    I'd appreciate any help/opinions.

  2. Dan H

    Dan H Guest

    Inverted usually means logically inverted as you describe

    A parallel port usually needs some type of timing pulse to indicate
    whent then should be sampled.

  3. Daenris

    Daenris Guest

    Well, the description says that pins 1-8 of the 15 pin are the data,
    pin 9 is +5v and pin 10 is ground, the other 5 pins are unconnected. I
    think that the experiment device is probably sampling that input
    regularly to see what the signal is. The parallel port signal is
    changed via a command in our experiment presentation.

  4. Si Ballenger

    Si Ballenger Guest

    I've got a page below that might give you some interface ideas
    for the parallel port. I use the status lines for input, but you
    might use a similar setup to input to bidirectional data pins and
    save some $$$.
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