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From: lawson@suphys.physics.su.OZ.AU (Peter Lawson)
Newsgroups: comp.os.msdos.programmer
Subject: Re: Programming interrupts on an AT
Message-ID: <1991Jun21.065609.17794@metro.ucc.su.OZ.AU>
Date: 21 Jun 91 06:56:09 GMT
References: <1991Jun20.150436.19167@visix.com>
Sender: news@metro.ucc.su.OZ.AU
Organization: Sydney University Computing Service, Sydney, NSW, Australia
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> lawson@suphys.physics.su.OZ.AU (Peter Lawson) writes:
>>I would like to know how to program interrupts on an AT, and I would be
>>very grateful for good references.  ...
> 
 Jim Edwards-Hewitt writes 
> 
> The other information that's useful to have (which I unfortunately
> don't have a reference for at the moment) is what devices use what
> interrupts.  That way you don't change your hard disk or keyboard
> interrupt accidentally. 
> 

I'm using a National Instruments AT-DIO-32F interface card. The manual
that comes with it has the following to say:

Do NOT use interrupt line 6 or interrupt line 14. Interrupt 6 is
used by the diskette drive controller, and interrupt line 14 is used
by the hard disk controller on most IBM PC AT's and compatibles.

My NEC APC IV System Reference Guide is somewhat more explicit, but I'm
not sure how general it is. For what it's worth it has the following
table:

IRQ00	Timer counter #0 output
IRQ01	Keyboard (output buffer full)
IRQ02	INT output from the slave 8259A [interrupt controller]
IRQ08	Realtime clock
IRQ09	Software INT0AH
IRQ10	Reserved
IRQ11	Reserved
IRQ12	Reserved
IRQ13	80287
IRQ14	Fixed disk controler
IRQ15	Reserved
IRQ03	Serial port 2
IRQ04	Serial port 1
IRQ05	Parallel port 2
IRQ06	Floppy disk controller
IRQ07	Parallel port 1

The ones marked "Reserved" are the ones you can use.  IRQ00-IRQ07 are
on the Master 8259A, and IRQ08-IRQ15 are through the Slave 8259A.

Peter.

Astronomy Department, Sydney University
NSW 2006 Australia.