Article View: comp.os.msdos.programmer
Article #7219Re: Need help setting DTR or RTS high or low
From: Matthew Smith
Date: Fri, 21 Jun 1991 19:02
Date: Fri, 21 Jun 1991 19:02
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In article <0094A6B3.5314B580@MAPLE.CIRCA.UFL.EDU> sorrow@oak.circa.ufl.edu writes: >I need some code examples on how to set the DTR or RTS line on a >RS-232C port high or low. C or asm would be fine. > >Thanks, > >Brian >/* >Brian Hook -- MS-DOS Programmer for Contract The Modem Control Register (address base address+0x04) is a bit mask of the various control lines, DTR, RTS, CTS, etc... To turn on RTS, turn on bit 1 (of bits 0-7 0=LSB), and to turn it off, set it to 0. DTR is controlled by bit 0 in the same register. I hope this helps you out. I figured it would be better than code... Matt Smith msmith@peruvian.utah.edu University of Utah Department of Computer Science
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arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!uakari.primate.wisc.edu!caen!hellgate.utah.edu!peruvian.utah.edu!msmithReferences:
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!uakari.primate.wisc.edu!caen!hellgate.utah.edu!peruvian.utah.edu!msmith From: msmith%peruvian.utah.edu@cs.utah.edu (Matthew Smith) Newsgroups: comp.os.msdos.programmer Subject: Re: Need help setting DTR or RTS high or low Message-ID: <1991Jun21.130204.6197@hellgate.utah.edu> Date: 21 Jun 91 19:02:04 GMT References: <0094A6B3.5314B580@MAPLE.CIRCA.UFL.EDU> Organization: University of Utah CS Dept Lines: 24