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Path: utzoo!utgpu!water!watmath!clyde!rutgers!mcnc!uvaarpa!virginia!babbage!mac3n
From: mac3n@babbage.UUCP
Newsgroups: comp.sys.ibm.pc
Subject: Re: Interrupt's for the COM ports on a PS/2 model 50
Message-ID: <132@babbage.acc.virginia.edu>
Date: Fri, 4-Dec-87 16:16:57 EST
Article-I.D.: babbage.132
Posted: Fri Dec  4 16:16:57 1987
Date-Received: Wed, 9-Dec-87 20:54:18 EST
References: <16803@gatech.edu>
Organization: University of Virginia
Lines: 9
Keywords: interrupts,serial,com,port,pia
Summary: 8259 PIC edge / level triggered

In article <16803@gatech.edu>, paj@gatech.edu (P. Allen Jensen) writes:
> port and it does not work on the PS/2 model 50
> 
> The program sets up the 8259 to enable
> interrupts from the serial port.  The 8259 used

The 8259 triggers interrupts off the IRQ lines either by edge or by level.
In the PC it's edge, making it hard to share IRQ lines.
I believe this changed to level in the PS/2.