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From: keen@ee.ualberta.ca (Jeff '876393' Keen)
Newsgroups: comp.sys.apple2
Subject: Re: More extended graphics on the IIgs
Message-ID: <1991Jan23.172549.1096@ee.ualberta.ca>
Date: 23 Jan 91 17:25:49 GMT
References: <1991Jan18.170510.1@gacvx1.gac.edu> <14908@smoke.brl.mil> <1991Jan20.123430.7039@ee.rochester.edu> <14923@smoke.brl.mil>
Sender: news@ee.ualberta.ca
Organization: University of Alberta Electrical Engineering
Lines: 19

In article <14923@smoke.brl.mil> gwyn@smoke.brl.mil (Doug Gwyn) writes:
>In article <1991Jan20.123430.7039@ee.rochester.edu> seah@ee.rochester.edu (David Seah) writes:
>>Not having a VOC myself, what is it about this board that messes up
>>3200 color demos?
>
>Basically, in order to synchronize with an external video source, it
>provides a duplicate IIGS video subsystem that is not synchronized to
>the one on the motherboard.  Unfortunately the existing 3200-color
>demos use the motherboard clock-based signals to coordinate their
>updates of scan-line control bytes during the painting of the image.
>The effect is that the VOC is using the wrong SCB information since
>it is updated out of sync with the VOC scanning.


-- 
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Jeff Keen    University of Alberta
keen@bode@alberta                  
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