Path: utzoo!mnetor!tmsoft!torsqnt!news-server.csri.toronto.edu!rutgers!cbmvax!daveh
From: daveh@cbmvax.commodore.com (Dave Haynie)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Simple Frame Buffer boards
Message-ID: <16625@cbmvax.commodore.com>
Date: 18 Dec 90 13:53:23 GMT
References: <916@boing.UUCP> <23699@grebyn.com> <918@boing.UUCP> <1411@mpirbn.mpifr-bonn.mpg.de> <920@boing.UUCP> <90345.181101L98CC@CUNYVM.BITNET>
Reply-To: daveh@cbmvax.commodore.com (Dave Haynie)
Organization: Commodore, West Chester, PA
Lines: 22

In article <90345.181101L98CC@CUNYVM.BITNET> L98CC@CUNYVM writes:
>In article <920@boing.UUCP>, dale@boing.UUCP (Dale Luck) says:
>>IMHO the benefits of a complete memory mapped frame buffer far outweigh
>>the costs giving up 1-2M of address space on the bus. The benefits of
>           *******************************

>1) I am willing to give up 2 meg space but not expansion ram space.
>3) I do not want to violate any hardware design rule set by CBM. ( i.e.
>  do not use reserved address space etc.. )

These two desires are at odds with one another.  The only memory mapped
hardware supported is autoconfiguring hardware.  There is 8.5 meg of space
open for this, 8 of which is contiguous and many folks use for expansion
RAM.  If you want a memory mapped frame buffer that takes up 2 meg for it's
mapped memory, that leaves 6 meg of space for other things, including 
expansion RAM.  There is no other memory available on a 68000 system.


-- 
Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests"
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		"I can't drive 55"	-Sammy Hagar