Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!olivea!tymix!tardis!jms
From: jms@tardis.Tymnet.COM (Joe Smith)
Newsgroups: comp.sys.amiga.graphics
Subject: Re: Amiga Display Resolution Modes.
Summary: A2024 does not require ECS
Message-ID: <1454@tardis.Tymnet.COM>
Date: 22 Jan 91 04:59:50 GMT
References: <1991Jan14.024715.1@ccvax.iastate.edu>
Reply-To: jms@tardis.Tymnet.COM (Joe Smith)
Organization: BT Tymnet, San Jose, CA
Lines: 32

In article <1991Jan14.024715.1@ccvax.iastate.edu> taab5@ccvax.iastate.edu (Marc Barrett) writes:
>In Message <1419@tardis.Tymnet.COM> <jms@Tardis.Tymnet.COM> writes:
>>>Question: What display modes does the Amiga have?  >>Answer: Lots.
>I took the table given in the original message, and altered it to make
>it a little more sensible.

You did a good job, Marc, except for one line.  A2024 belongs up in the
first table with "Normal Denise".

>A2024                     1008x800   1008x1024   2        16***
>*** The Commodore A2024 monitor is a gray-scale monitor.  In the maximum
>   resolutions given in the table, it displays a maximum of 4 shades of
>   gray out of a palette of 16 shades of gray.  This monitor requires the
>   ECS, and so is listed with the ECS resolution modes.
    ^^^ Not required.
>                                 -MB-

The resolution of 1008x800 is sent out as either 4 or 6 panels.  The bits
are sent out as {lines 0-399, pixels 0-639} + {lines 0-399, pixels 640-1007}
+ {lines 400-799, pixels 0-639} + {lines 400-799, pixels 640-1007} (or
something like that).  This is using the normal Denise, using approx. 640
pixels per scanline at 15KHz.  All the magic is done via software (a new
graphics.library) in the Amiga and hardware inside the A2024 "Hedley"
monitor.  When changing the entire screen (such as using Left-Amiga-M), it
takes 4 fields (1/15 second) to get all the pixels updated.  The A2024-15Hz
mode uses up as much Chip-RAM bandwidth as a 640x400x16-color screen.  The
A2024-10Hz mode uses up less bandwidth, as much as a 640x400x8-color screen.
-- 
Joe Smith (408)922-6220 | SMTP: jms@tardis.tymnet.com or jms@gemini.tymnet.com
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