Article View: comp.sys.ibm-pc
Article #1COM1 interrupts
From: Glenn Cadoret
Date: Tue, 22 Aug 1989 14:56
Date: Tue, 22 Aug 1989 14:56
19 lines
1072 bytes
1072 bytes
I have been trying to write a program for an IBM-AT which will catch
interrupts from COM1. It is my understanding that three things must be done
to enable this type of interrupt:
1) Bit 7 of 0x3FB must be set low
2) Bits 0-3 of 0x3F9 must be set high
3) Bit 4 of 0x21 must be set low
I do all of these things, but I still don't see an interrupt. Specifically,
I am interested in the interrupt which is generated when a character comes
into the port.
If anyone could suggest why program is not working, it would be greatly
appreciated.
Many thanks,
Glenn
Replies to: gc0d@andrew.cmu.edu (E-mail)
(703) 760-1429 (Voice)
Technical Details
Message-ID:
<oYwKauu00WB3IJNEhE@andrew.cmu.edu>Path:
arc1-ca.pugleaf.net!utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!uflorida!gatech!udel!rochester!pt.cs.cmu.edu!andrew.cmu.edu!gc0d+Show Full Headers
Complete Article Headers
Path: arc1-ca.pugleaf.net!utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!uflorida!gatech!udel!rochester!pt.cs.cmu.edu!andrew.cmu.edu!gc0d+ From: gc0d+@andrew.cmu.edu (Glenn Cadoret) Newsgroups: comp.sys.ibm-pc,comp.sys.ibm.pc Subject: COM1 interrupts Message-ID: <oYwKauu00WB3IJNEhE@andrew.cmu.edu> Date: 22 Aug 89 14:56:58 GMT Followup-To: comp.sys.ibm-pc Organization: Physics, Carnegie Mellon, Pittsburgh, PA Lines: 19