From:	neil AT robots DOT ox DOT ac DOT uk (Neil Townsend)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Detecting interrupt on printer port
Date:	Fri, 21 Aug 1998 11:36:02 GMT
Organization:	None evident here.
Lines:	19
Message-ID:	<1998Aug21.113602.13782@catorobots.ox.ac.uk>
References:	<_yLB1.90$Na1 DOT 583337 AT sapphire DOT mtt DOT net> <35d7c57b DOT 36585684 AT news DOT rapidnet DOT net>
NNTP-Posting-Host:	cato.robots.ox.ac.uk
Originator:	neil AT cato
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

In comp.os.msdos.djgpp richard AT stardate DOT bc DOT ca writes:
>On Mon, 17 Aug 1998 01:19:54 GMT, "Michel Gallant"
><mgallant AT NOSPAM DOT grassroots DOT ns DOT ca> wrote:
>
>>Hi!  I'm back, and with more problems than ever.  Below is the progam
>>I'm using....  Incorporating all the suggestions (I think) made to me
>>thus far regarding this program.  It still doesn't work.  I used a
>>logic probe, and verified that Interrupt Request Line 07 
>
>The problem may be that the interrupt is masked out in the PIC. 
>Bit 7 (the most significant bit) of port 0x21 needs to be set to 1. 

If I remeber correctly, the interupt in question is interupt 15. 0x21
controls interupts 0-7. Interupts 8-15 are controlled by 0xa1, I believe. As
has been noted elsewhere, the bits are 'active low'.

Neil
-- 
Neil Townsend   +44 (1865) 273121   neil AT robots DOT ox DOT ac DOT uk

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