Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uwm.edu!rpi!brutus.cs.uiuc.edu!uakari.primate.wisc.edu!ames!elroy.jpl.nasa.gov!aero!goldstein@arecibo.aero.org From: goldstein@arecibo.aero.org Newsgroups: comp.sys.ibm.pc Subject: Silly question about parallel port reading Message-ID: <67236@aerospace.AERO.ORG> Date: 21 Feb 90 06:57:55 GMT Sender: news@aerospace.aero.org Organization: The Aerospace Corporation Lines: 31 -Message-Text-Follows- Hi. I'm sure the answer to this is obvious, but I haven't been able to find good documentation on it. Please email me directly to prevent irritating other users of this group. Thanks! The problem: transfering data from an obsolete compatible-to-nothing computer to my PC compatible. The only ports they have in common is a parallel port. Should be easy, then, to read in with my PC from the output of the other. Well, it's not. The other machine (UnComp) has d0-d7 hooked up directly to the parallel port, and only identifies transmission by pulling strobe-bar low when it's sent a byte. It does also observe busy-bar. My PC compatible should be reading the parallel port by setting bit 5 of the parallel control register (at 37A hex) high, and reading the values from 378 hex. (At least, I think it should.... am I right?) The problem seems to be that the old UnComp is flipping d0-d7 around continuously, and, of course, when it's putting out a high bit on any of those when my PC is keeping the line low, I get trouble. I know that the PC is capable of reading through the parallel port, since I tested it with LapLink and it worked beautifully. How stupid am I being? What am I missing? Any advice? ___Samuel___ _________I_claim_and_accept_sole_responsibility_for_the_above._SjG.____________ | "I should have been a pair of ragged claws, | Scuttling across the floors of silent seas." (213) 336-3592 (9-5, M-F) | -- J. Alfred Prufrock (T. S. Eliot) Thank you!