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Article #3602Re: H-E-L-P!! An interesting UART problem.
From: Ilan Berkner
Date: Wed, 11 Nov 1992 14:11
Date: Wed, 11 Nov 1992 14:11
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The only way to do this would be to either: 1. Attach an ISR to vector 14h, and _hope_ that all of your client's software will only be using int 14h calls to xmit data. This is like hoping that the moon will turn around in orbit so you can see the other side. 2. or put the computer into virtual mode, and write an ISR that traps 386 I/O priviledge exceptions. This technique will only work on 386-class machines, and is incompatible with Windows enhanced mode, 386MAX, QEMM, Desqview, OS/2 2.0, etc. Sorry, but there's no way to trap I/O, and the UART can't do interrupts on transmits, as you found out.
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Newsgroups: comp.os.msdos.programmer,comp.sys.ibm.pc.programmer Path: arc1-ca.pugleaf.net!sparky!uunet!seas.gwu.edu!ilan From: ilan@seas.gwu.edu (Ilan Berkner) Subject: Re: H-E-L-P!! An interesting UART problem. Message-ID: <1992Nov11.141104.7451@seas.gwu.edu> Sender: news@seas.gwu.edu Organization: George Washington University References: <1992Nov10.094131.9300@iccgcc.decnet.ab.com> Date: Wed, 11 Nov 1992 14:11:04 GMT Lines: 15