Article View: comp.sys.amiga.tech
Article #9704Re: BridgeBoard & VGA problems
From: Jarek Baryeka
Date: Tue, 06 Sep 1988 16:31
Date: Tue, 06 Sep 1988 16:31
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daveh@cbmvax.UUCP (Dave Haynie) says:
>But what you just said sounds impossible. At least as I understand it,
>the PC-XT, being 8088 based, is limited to a total of 1 meg normal address
>space, plus 64K or so I/O space. The MDA, CGA, EGA, and the various other
>cards sit up in higher memory and by default must take less than the space
>that's left over in the PC. If VGA really takes up 512K of directly
>addressable memory, it must either be unsuitable to an XT compatible, or
>use some generally unused addressing mode, like the 16 bit I/O addressing
>that the Z-80 can do, but generally doesn't do.
The VGA needs only 256K (the 512K are used for some modes going beyond
the VGA resolution).
>There are jumpers on the bridge card to turn off it's CGA or MDA emulation;
>the manual should explain this.
I have managd to get a german manual but they are talking about 8-pin jumper -
my jumperhas only 6 pins.
>This is all a prime example of what's broken on PC[lone] machines....
I agree, but in this case the BridgeBoard seems to be even more broken than
the PCs - the card works with other PC-XT clones.
>--
>Dave Haynie "The 32 Bit Guy" Commodore-Amiga "The Crew That Never Rests"
> {ihnp4|uunet|rutgers}!cbmvax!daveh PLINK: D-DAVE H BIX: hazy
> "I can't relax, 'cause I'm a Boinger!"
>----------
Thanks for your help,
Jarek Baryeka.
Technical Details
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arc1-ca.pugleaf.net!utzoo!utgpu!water!watmath!clyde!att!rutgers!mit-eddie!ll-xn!ames!pasteur!ucbvax!hplabs!hpl-opus!hpccc!baryekaReferences:
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!water!watmath!clyde!att!rutgers!mit-eddie!ll-xn!ames!pasteur!ucbvax!hplabs!hpl-opus!hpccc!baryeka From: baryeka@hpccc.HP.COM (Jarek Baryeka) Newsgroups: comp.sys.amiga.tech Subject: Re: BridgeBoard & VGA problems Message-ID: <1760002@hpccc.HP.COM> Date: 6 Sep 88 16:31:26 GMT References: <1760001@hpccc.HP.COM> Organization: HP Corporate Computing Center Lines: 35