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8bit Friendly ISA VGA cards

Moogle!

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I would like to add 3 cards I have confirmed to work in 3 different 8 bit systems. These were not extensively tested beyond booting into DOS 6.22. The systems tested were an IBM XT 5160 with the 1982 BIOS; a Hedeka 919, which is an odd 286 based XT with only 8 bit slots and a switchable 10Mhz / 4.77Mhz mode; and an XI 8088 in a third party backplane that is all 16 bit slots with BIOS 0.9.9.

There is a Video Seven VEGA VRAM, an OEM Trident Board, and an Everex with the Accumos AVGA1 chipset. The Video 7 card needs switches 6 and 7 to be in the off position, the Trident and Everex seem to autosense. I have found that using the XI8088 with the 16 bit backplane seems to throw off some cards, such as one of the ATI VGA Wonders.

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Moogle!

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Something to beware of, just because the chip supports 8 bit mode doesn't mean the card does. Here are two cards I cannot get to work in any of the three systems mentioned in the preceding post. I am reasonably certain The Oak 0TI037C card simply does not appear to support 8 bit mode despite the datasheet mentioning PC support.

I am not certain what all the switches on the Cardinal do, since there is no documentation to be found anywhere, but the switches are in the state I received it in, and it does not show a display in an 8 bit slot.
 

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Eudimorphodon

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Oak 0TI037C card simply does not appear to support 8 bit mode despite the datasheet mentioning PC support.

The *only* thing that's 16 bit on an OTI-037 card is BIOS access. I mean, literally, that's it. The VGA itself is *entirely* 8 bit. If one of those jumpers doesn't set 8-bit mode then maybe this one is trying to autodetect and failing?
 

Moogle!

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The *only* thing that's 16 bit on an OTI-037 card is BIOS access. I mean, literally, that's it. The VGA itself is *entirely* 8 bit. If one of those jumpers doesn't set 8-bit mode then maybe this one is trying to autodetect and failing?


It would seem none of the jumpers control 8 bit access. I know my 067 card had jumpers that had to be changed.
 
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Eudimorphodon

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Looking at the photo of the card it’s… weird. Found another set of front and back photos here:


And… I know this is probably a multi-layer circuit board, so there could be traces buried, but it almost looks like there aren’t any traces running from the 8-bit side of the board to the ODD ROM chip’s data lines? (there are address lines bridged over) Unless there’s another set buried in there it almost looks like this card may well be “obligated” to run in a 16 bit slot?

FWIW, that would be a terrible design choice. It’d likely cause conflicts with any other card you might install that has 8 bit BIOS ROMs.
 

Zare

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I have issues with TVGA9000i-2 in 8bit mode. It doesn't work. The machine doesn't have an error beeper.

Another card tested is TVGA8900C which works jumperless. In XT it reports 256kB memory, in Pentium machine it reports 1M of memory.

When I plug TVGA9000i-2 in Pentium it boots with 512kB regardless of being jumped to 8 or 16 bit and it always has (16) at the end of the version string.
 

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Zare

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I might add that reason why I want 9000 instead of a working 8900C is the height profile. The machine can take a card about a millimeter taller than above attached TVGA.
So if anyone has any tips of what other cards to look at I would appreciate it. The Everex from Moogle!'s post looks like a good fit but I can find only sellers from USA in Ebay.
 

boggit

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Jan 4, 2024
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[h="1"]TSENG[/h]
  • ET4000 chipset XVGA based card from Focus Information Systems Inc. (autosense)
  • ET4000 chipset from Diamond Speedstar. (switches 1/3 off)
Would a w32 version of an ET4000 based 16-bit VGA card work in an 8-bit ISA slot?

From what I've understood, the w32 ones were released relatively late, so I figured it might not work too well in an 8-bit slot, but maybe someone here knows?
 

dr.zeissler

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Jan 4, 2014
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I did a bit of an experiment where I made Anamorphic 800x600 32k color images and hooked up my Vendex to my 65" LG OLED. I made a video with several slide show images. I attached some of the pictures of the OLED and a zip file with the Anamorphic 800x600 images in case anybody else has their old PC connected to a widescreen display and wanted to see how they look. In the video I removed some of the image loading but you can still get a sense of how slow it is even with the 286 accelerater.


Anyway, it does show how the Diamond Speedstar 24 is a) compatible with an 8 bit slot and b) can do 32k with a VESA 1.2 Driver.
If you do hires gfx (256+ colors) on an early VGA card, please use TGA as format and quickview 1.3 as viewing program.
it loads and displays the big files like charm...even on very lowend machine. example (286/8 1024x768 256colors)
 
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