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From: ressler@CS.Cornell.EDU (Gene Ressler)
Subject: Re: Programming the printer port to read in data.
Message-ID: <1991May22.151055.25592@cs.cornell.edu>
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Date: Wed, 22 May 1991 15:10:55 GMT
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In article <1991May22.104513.22169@msuinfo.cl.msu.edu> draper@buster.cps.msu.edu (Patrick J Draper) writes:
>Some people have given suggestions to use a joystick port, etc to read
>a switch.
>
>What if someone wanted to read a signal from a sound digitizer?
>How do you get the port to read a parallel data stream?

This is to point out that the July 90 BYTE has a blurb on using a printer port
to read and write TTL level signals from/to a Mattel power glove.  There's
wiring and example code.  Only a couple of bits are used here, but it's easy
to generalize to other appications.  I'm sure there are other, perhaps more
general references for doing the same thing, perhaps even other BYTE articles.
One caveat is that I seem to remember the original PC (and therefore the oldest
and/or cheapest clone) printer ports couldn't read the data lines.  There was
a simple hardware hack to fix this, I believe cutting a trace and/or adding
a jumper to the board.

Gene