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Article #574Re: Vertical Retrace interrupt?
From: Ross Ridge
Date: Tue, 11 Aug 1992 12:46
Date: Tue, 11 Aug 1992 12:46
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Ross Ridge <ross@zooid.guild.org> writes: >This is true of any type of card, no two devices on the ISA bus can >generate the same IRQ. tmkk@uiuc.edu (Khan) writes: >Really? Then why can my COM1:, which is on the motherboard, coexist with >my COM3:, which is on a separate modem card? Both generate IRQ4. Because you never use them them at the same time. If your modem and on-board serial port generate IRQ4 at the same time they'll short each other out. >>The problem is electrical, because of the way the ISA bus is designed >>you risk serious damage if two devices on the bus share the same interrupt. > >What's your source for this? It's a well known limitation of the IBM PC bus. Ross Ridge -- Ross Ridge - The Great HTMU l/ // [OO][oo] ross@zooid.guild.org /()\/()/ uunet.ca!zooid!ross db //
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<1992Aug6.154949.164290@dstos3.dsto.gov.au> <BsJx5H.FKy@watserv1.uwaterloo.ca> <Bsrt25.GF1@news.cso.uiuc.edu>Show Full Headers
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Newsgroups: rec.games.programmer,comp.sys.ibm.pc.hardware Path: arc1-ca.pugleaf.net!sparky!uunet!zaphod.mps.ohio-state.edu!uunet.ca!geac!zooid!ross From: Ross Ridge <ross@zooid.guild.org> Subject: Re: Vertical Retrace interrupt? Organization: ZOOiD BBS Date: Tue, 11 Aug 1992 12:46:19 GMT Message-ID: <1992Aug11.124619.9641@zooid.guild.org> Followup-To: comp.sys.ibm.pc.hardware References: <1992Aug6.154949.164290@dstos3.dsto.gov.au> <BsJx5H.FKy@watserv1.uwaterloo.ca> <Bsrt25.GF1@news.cso.uiuc.edu> Lines: 26