Re: [PARPORT] Reading from pin - help.

From: Matthew Duggan (
Date: Thu Dec 19 2002 - 20:25:19 EST

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    Pawel Stochlinski wrote:
    > The program idea is to read a data from dallas 1820 temperature sensor
    > is connected to the PIN 10 (ACK) of LPT port.
    > All i want to do, is to use a simple, quick code that will read the
    pin 10.
    > All i have red about reading paraller ports is to use:
    > x=inb(STATUS); (for statusports)
    > Hey, but this is not all! I want to read a BYTES from pin 10, not a
    state of
    > ALL pins in statusport.
    > Please, tell me, how can i read ONE pin (for example pin nr. 10[ACK]),
    > there any quick, simple method?


    If I understand you correctly, you wish to *serialise* the information
    on pin 10 of your *parallel* port. That's not as easy as it sounds. To
    know that the data has changed, you need two timing pins (clock in, ack
    out) for a start.. one pin is not enough. Once you have that, you need
    to busy-read the port, read in a new bit whenever the clock signal goes
    high, set ack high, wait for clkin to go low set ack low, etc, etc.
    It's ugly, but serialising data from a single pin of the parport isn't a
    particularly common task.

    - Matthew

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