VOGONS


First post, by digger

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So I just saw this topic pop up: Newly made ISA CL-GD5434

And I was amazed to read there that some GPUs commonly found in PCI cards could be used as a basis for creating ISA cards as well.

It made me wonder: would it be possible to design a new ISA VGA card with a DVI port? Either by basing it on a GPU chip that does not have an integrated RAMDAC, or by finding a more recent GPU chip with DVI support that could be made to work in an ISA card with reasonable effort?

Reply 2 of 15, by cyclone3d

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You could.. but why? DVI is pretty much dead on new monitors and with older monitors, you can just us a passive adapter since most monitors that support DVI also support the analogue signal through the DVI port.

What gets tricky is if you want to take a vga signal and convert it to digital DVI.

Probably way better to have a card with DVI integrated.. but still why? It would be way better to have HDMI or Displayport... but then you would lose the lower DOS resolutions anyway which would yet again make the card pretty pointless.

And you would have to worry about making custom drivers if you use a newer GPU.

Since yo have a RAMDAC on pretty much all if not all ISA cards, couldn't you just hook into the digital side and make some sort of add-on in order to output a digital signal?

Actually, I just did a quick search and it seems like it just might be possible to make an add-on to do this:
VGA Digital Output

Yamaha YMF modified setupds and drivers
Yamaha XG resource repository - updated November 27, 2018
Yamaha YMF7x4 Guide
AW744L II - YMF744 - AOpen Cobra Sound Card - Install SB-Link Header

Reply 3 of 15, by digger

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Yeah, I really should have been clearer here about the goal I had in mind: an ISA card with excellent register-level ("legacy") VGA compatibility as well as very good VBE 2.0 and 3.0 support, but with digital signal output without going through any analog step.

So no integrated VGA-to-DVI adapter or anything like that.

And HDMI or even DisplayPort instead of DVI would be fine too. The all-digital part would be the key aspect.

But the option of using the feature connector for something like this sure looks interesting.

Reply 4 of 15, by Tiido

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I have something started that can do that but there's plenty of time until it actually gets finished. Some other things are in the way and once I have time I probably lack money and things get delayed even more 🤣. http://www.tmeeco.eu/TKAVIVC/T-01VIVC-A.png

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Reply 5 of 15, by derSammler

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digger wrote on 2020-04-03, 23:52:

would it be possible to design a new ISA VGA card with a DVI port?

And the point would be..? An ISA VGA card limits what games you can play. You are pretty much stuck at games running in 320x200 and this causes virtually no image degradation when using an analog connection over a good, shielded cable to a monitor (no VGA resolution actually does).

In conclusion, what you want is to connect an ISA VGA card via DVI/HDMI/DP to a modern monitor, which then completely fucks up the picture by up-scaling?

Reply 6 of 15, by digger

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Tiido wrote on 2020-04-04, 07:42:

I have something started that can do that but there's plenty of time until it actually gets finished. Some other things are in the way and once I have time I probably lack money and things get delayed even more 🤣. http://www.tmeeco.eu/TKAVIVC/T-01VIVC-A.png

Yeah, that looks pretty much like what I had in mind. Would it require VLB, or would it also work in ISA slots, both 16-bit and 8-bit? One card to rule them all, so to speak? 😉

Between this, the PCI(e)/ISA converter and other stuff, you sure are working on some impressive and much-desired projects. These are things that go over many other people's heads in terms of implementation complexity. Surely we could get some kinds of crowdfunding efforts going so you could actually make a living off of designing and producing retro hardware like this?

Reply 7 of 15, by digger

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derSammler wrote on 2020-04-04, 07:47:
digger wrote on 2020-04-03, 23:52:

would it be possible to design a new ISA VGA card with a DVI port?

And the point would be..? An ISA VGA card limits what games you can play. You are pretty much stuck at games running in 320x200 and this causes virtually no image degradation when using an analog connection over a good, shielded cable to a monitor (no VGA resolution actually does).

In conclusion, what you want is to connect an ISA VGA card via DVI/HDMI/DP to a modern monitor, which then completely fucks up the picture by up-scaling?

Fair point about the low res, but perhaps the skipping of digital->analog->digital conversion might still help a bit in terms of color fidelity?

Also, perhaps such a card could be equipped with a highly optimized integrated scaler for legacy VGA resolutions that might result in better picture quality on monitors that only have rudimentary or passable scaling support for such lower resolutions for the sake of legacy compatibility without caring about quality too much? Also built-in scalers in newer monitors, as well as many external scalers, tend to have difficulty with some non-standard legacy VGA resolutions and refresh rates.

Reply 8 of 15, by Tiido

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digger wrote on 2020-04-04, 07:51:

Yeah, that looks pretty much like what I had in mind. Would it require VLB, or would it also work in ISA slots, both 16-bit and 8-bit? One card to rule them all, so to speak? 😉

Between this, the PCI(e)/ISA converter and other stuff, you sure are working on some impressive and much-desired projects. These are things that go over many other people's heads in terms of implementation complexity. Surely we could get some kinds of crowdfunding efforts going so you could actually make a living off of designing and producing retro hardware like this?

VLB+ISA would mean it works in VLB and also ISA. 8bit is also possible though not exactly in the plans. Hard part is the software, video BIOS will be the biggest challenge.

There's a lot of stuff I want to do (bus mastering IO card, whole motherboard even) but there's the everlasting problem with money. Ideally I would like to live off this stuff but it hasn't really worked so far 🤣. I need to finish couple stuff for other people first before I can continue with my own things...

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Reply 9 of 15, by Sphere478

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I was actually just googling this and came to this thread.

I think dvi is the best port for a video card, because you have vga, component, digital dvi, and digital for hdmi or display port all in one port you just need an adapter for vga and hdmi

I’ve literally avoided buying graphics cards because of lack of dvi because none of the monitors I own supports it anymore.

Sure I could get a retro monitor but I would have to clear a special place for it.

I have several vga to hdmi adapters but they always seem to either not work right or at all.

It’s just an extra step. The card should have dvi. Plain and simple.

Now, that all said, it’s fully understandable that a isa gfx card wouldn’t have it. But, that was long before digital monitor signaling

That was then, it’s time we had a digital option for this digital time. To use with our digital monitors! 😀

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Reply 10 of 15, by jmarsh

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Sphere478 wrote on 2021-11-28, 11:03:

I think dvi is the best port for a video card, because you have vga, component, digital dvi, and digital for hdmi or display port all in one port you just need an adapter for vga and hdmi

It doesn't have audio (at least standard DVI doesn't) and can't support the higher resolutions/bitdepths/modes that HDMI and DisplayPort do, making it a subpar choice for modern sytems.

Reply 11 of 15, by Sphere478

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Yes yes, but it’s more than enough for pluging retro into modern display. Many retro can do spdif also. Or just regular 3.5mm to rca

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Reply 12 of 15, by mihai

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Sphere478 wrote on 2021-11-28, 11:03:

I have several vga to hdmi adapters but they always seem to either not work right or at all.

There are good VGA - HDMI converters out there, but expensive; an example: https://www.extron.com/product/rgbhdmi300a

Reply 13 of 15, by sdz

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Can't say exactly when, but at some point I plan to make this work with most cards that have an external RAMDAC. VGA port will still work. There's no scaling at the moment, but it could be added later on.

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Reply 14 of 15, by Tiido

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That's a good idea, tapping into the RAMDAC. Most of them are pin compatible too ~

T-04YBSC, a new YMF71x based sound card & Official VOGONS thread about it
Newly made 4MB 60ns 30pin SIMMs ~
mida sa loed ? nagunii aru ei saa 😜

Reply 15 of 15, by Sphere478

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sdz wrote on 2021-11-28, 15:30:
Can't say exactly when, but at some point I plan to make this work with most cards that have an external RAMDAC. VGA port will s […]
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Can't say exactly when, but at some point I plan to make this work with most cards that have an external RAMDAC. VGA port will still work. There's no scaling at the moment, but it could be added later on.

20200724_014822.jpg
20200724_014812.jpg
20200831_133454.jpg

That’s interesting…

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