Article View: comp.sys.mac
Article #8193Mac Serial ports
From: David Palmer
Date: Tue, 21 Nov 1989 01:12
Date: Tue, 21 Nov 1989 01:12
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I am wiring up a micro-controller (an (oh the shame of it) Intel 8052 with a built-in (double shame) BASIC interpreter) This controller has a TTL (0 - 5V) input-output serial port. What do I need to do to get my Mac to speak to it? I am wiring my own cable. Do I have to wire the RxD- line on the Mac to set it to +2.5 V so that the differential goes positive and negative? or does it drift to that value automatically? Also, the controller serial port is set up to use an inverting buffer. Is it reasonable to just use the RxD- and TxD- lines from the Mac, and wire the RxD+ line to +2.5V? This would eliminate another chip from what is now a 4-chip design, which is aesthetically pleasing even if it is bad engineering practice. Thanks in advance. David Palmer palmer@tybalt.caltech.edu ...rutgers!cit-vax!tybalt.caltech.edu!palmer Meanwhile, on eng.string.floss, the waxed vs. unwaxed flamewar continues unabated.
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arc1-ca.pugleaf.net!utzoo!attcan!uunet!mailrus!wuarchive!usc!henry.jpl.nasa.gov!elroy.jpl.nasa.gov!cit-vax!tybalt.caltech.edu!palmerShow Full Headers
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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!mailrus!wuarchive!usc!henry.jpl.nasa.gov!elroy.jpl.nasa.gov!cit-vax!tybalt.caltech.edu!palmer From: palmer@tybalt.caltech.edu (David Palmer) Newsgroups: comp.sys.mac Subject: Mac Serial ports Message-ID: <12742@cit-vax.Caltech.Edu> Date: 21 Nov 89 01:12:29 GMT Sender: news@cit-vax.Caltech.Edu Reply-To: palmer@tybalt.caltech.edu.UUCP (David Palmer) Organization: California Institute of Technology Lines: 22