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From: grege@gold.GVG.TEK.COM (Greg Ebert)
Newsgroups: sci.electronics
Subject: Re: Is PC parallel port latched?
Message-ID: <1170@gold.GVG.TEK.COM>
Date: 16 Jul 90 15:30:55 GMT
References: <33965@ut-emx.UUCP>
Organization: Grass Valley Group, Grass Valley, CA
Lines: 13

In article <33965@ut-emx.UUCP> ycy@walt.cc.utexas.edu (Joseph Yip) writes:
>Hi,
>
>I am trying to use IBM PC's parallel port (printer port) as digital
>output port. This will save me from buying a digital I/O card.

Yes, the parallel port uses a latched output driver, usually a 74xx373. It
also has readback, so if you write to the port you can read-back whatever
was written.

The I/O address is either 278h, 378h, or 3BCh. Use DEBUG to find it, or
look at 40:0 for the pointers. If you are only using the 8 data lines,
you don't need to worry about the status/control lines.