VOGONS


CRT Terminator Digital VGA Feature Card ISA DV1000

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Reply 100 of 110, by clb

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Shadow Lord wrote on 2024-10-28, 23:36:

Thanks but not exactly what I had in mind. I have done that myself as well but the formatting is not the greatest. I was looking more for something that was properly formatted with matching size pages. That way, if a user wanted to, it could be printed out as a booklet or easily viewed on a tablet without scrolling (I have an old tablet that I use only to read manuals off of. All the PDFs are on my local server and I can pull up a manual whenever/where ever when working on a system). I know the HW is the important bit and is taking all of your time but when/if you get the time you may want to consider a download section on your site where FW updates, any NECESSARY utilities, and the the manual can be easily downloaded. Having github is great but github doesn't help less technical users and not all the info there is needed to just be a user. Just a thought. Thanks and I am looking forward to getting my unit!

That's a great point. I took time today to work with CSS media queries to adjust the page layout specifically for print. That cleaned up the layout for printed PDF to look quite a bit nicer. Hopefully that helps a bit here.

Thanks for your support, we are now working on calculating actual shipping costs for everyone for the first shipping batch, and will soon post the PayPal checkout links. The nearest UPS drop-off point is some 100km away, so we will batch shipments, aiming to get the first batch out to UPS by next Monday.

Reply 101 of 110, by clb

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janih wrote on 2024-10-29, 08:15:

What happens if you input high/true color SVGA to CRT Terminator? Does it display anything?

Ahh, that is a great question.. The short answer is "maybe, try it out and tell us what happens".

As an example, here is one of my favorite ISA VGA adapters, Cirrus Logic CL-GD5422:

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In SEA image viewer, I was able to get a 640x480 @ 16bpp image out from it with CRT Terminator:

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The video timings coming out from the card are shown in the upper right. Note though that the Developer HUD right will look a bit different in the release version.

So 16-bit does work with that Cirrus Logic card at least. But then I have another newer Cirrus Logic CL-GD5430 card:

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which one might expect to be a "newer and better" version of that CL-GD5422 card, but for some reason, on that card the signal quality is worse than on the CL-GD5422, resulting in unstable high and true color video modes. (maybe recapping the CL-GD5430 might have some effect, idk)

So the long answer is that in testing, we see a large amount of variance on how the SVGA adapters decided to treat these video modes.

See, the VESA Feature Connector specification only ever talks about 8-bit video data. There is no official support for 15-bit, 16-bit or 24-bit video in the standard. The pixel bus is fixed 8 bits wide.

In the case of > 8bpp video modes, we see that some adapters simply turn off the FC bus output altogether.

Then we see that some adapters have been hardwired to only send lower 8 bits of the 16-bit/24-bit video signal out from Feature Connector (basically as a byproduct of how hardware wiring is done), discarding the >8 bits lanes (there are no physical outputs from the graphics chips for those bits to the Feature Connector), making it useless for high/true color.

Then we see that some adapters (like the CL cards above) start to double or triple clock the 16-bit/24-bit video modes over the 8-bit FC bus. This will carry all the pixel data at least, but greatly exceeding the maximum rated bandwidth capability of the FC bus, so the output can be unstable (like with CL-GD5430 card above).

And then in some rare cases, we see that the adapters will turn into DDR signaling to clock out the 15-bit and 16-bit video modes. This behavior was highly entertaining to observe the first time we stumbled across it. Trident TGUI9440, WDC WD90C31A-LR at least do this, possibly S3 Vision 864 as well but haven't been able to conclusively verify.

As more or less as a hidden easter egg feature, I did implement support for these different double-/triple-clocked and DDR addressing modes (that was some months of work, I really wanted it to work out!). But it is a wild west, which is why we eventually decided to exclude it from the advertised CRT Terminator feature set altogether. (there are a couple of hidden "easter egg" extra features like this)

So ultimately it is a for-tinkerers "maybe, give it a go and see" kind of a thing.

All the 8-bit palettized color modes, i.e. CGA, EGA and VGA are known to work on all compatible hardware.

Last edited by clb on 2024-10-30, 23:05. Edited 1 time in total.

Reply 102 of 110, by Shadow Lord

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clb wrote on 2024-10-29, 09:19:

That's a great point. I took time today to work with CSS media queries to adjust the page layout specifically for print. That cleaned up the layout for printed PDF to look quite a bit nicer. Hopefully that helps a bit here.

Yes. That is much better! Thank you.

Reply 103 of 110, by pan069

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This is a really cool project but I wish that the ISA card would have been an external box instead with a simple internal bracket and ribbon cable to expose the feature connector to the back of the machine. The card is quite expensive and for those with multiple machines on which this would be a great addition, it becomes unaffordable quite quickly.

Reply 104 of 110, by Shadow Lord

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pan069 wrote on 2024-10-29, 19:51:

This is a really cool project but I wish that the ISA card would have been an external box instead with a simple internal bracket and ribbon cable to expose the feature connector to the back of the machine. The card is quite expensive and for those with multiple machines on which this would be a great addition, it becomes unaffordable quite quickly.

I respectfully disagree. Yes, the card is expensive so buying more then one is burdensome but if these homebrew/hobby projects are not properly supported then we won't see them happen. As far as I know nobody is making a living off of one of these types of projects (I am not counting guys like TexElec who mostly mass produce other's designs for those of us who can't make our own). Switching from machine to machine would be a pain but this is such a nicer and neater solution then the box hanging off that we usually see. I would love to see someone incorporate one of the flux readers with a full fledged FDC that supports 8 drives and has connectors for everything form 8" to 3.5" drives. An all in one that lets you do everything without having bare PCB hanging off of your system.

Reply 105 of 110, by clb

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pan069 wrote on 2024-10-29, 19:51:

This is a really cool project but I wish that the ISA card would have been an external box instead with a simple internal bracket and ribbon cable to expose the feature connector to the back of the machine. The card is quite expensive and for those with multiple machines on which this would be a great addition, it becomes unaffordable quite quickly.

Thanks, that is a really interesting idea. One of the challenges with an external box is that the video signal quality starts to degrade the longer the Feature Connector signal becomes, and the 30cm long cable is getting to the limits of the signal stability. VESA standardized the upper limit of the FC bus at 37.5 MHz, but in practice we see the desire to go higher (e.g. the 640x480 @ 16bpp is 43.6 MHz, above the VESA rated specification). An external box would have to balance the cable length with signal quality. Not sure, maybe it would be feasible to have a 40cm or 50cm long cable that would be good enough for the signal and for an external box to lie flat behind a tower case (instead of having it dangle off the back end). The IDE40 and IDE80 pin cables with ATA33, ATA66 etc. standards can maybe serve as a reference, iirc 33 MHz ATA33 still managed with IDE40, but 66 MHz required the isolated grounds with IDE80 pin cables, so the quality drop-off exists somewhere in between.

One of the things in the "future ideas" category has been to ponder whether doing an external CGA/EGA -> DVI-D converter in this manner would be possible. That would be an external USB-C powered converter box exactly like you mention. Of course, CGA/EGA conversion has been done already by hoglet's RGBtoHDMI, so it would be a question of "could we provide any additional features for it to make any sense". But if we did, then maybe such an external converter box could then also have a pin ribbon header input for the Feature Connector to also enable converting VGA in the same box.

Reply 106 of 110, by Tiido

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Pixel clock is the hard part, since it isn't present. Although you can regenerate it since all the CGA/EGA cards should have same pixel timings, unlike VGA/SVGA things where things tend to be all over the place...

Signal integritywise, it will help to use an intermediate dongle to buffer the signals to a known impedance and then use a fitting cable+connectors to transfer it to final location.

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Reply 107 of 110, by clb

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That's true, converting external CGA and EGA will require doing clock reconstruction in order to interpret what the pixel clock will be. The fact that there were only few different possible pixels/scanline values for CGA and EGA will definitely help there.

I dropped the first batch of boxed up CRT Terminators off to UPS today, and the second batch of parcels will go out next Monday. We've got plenty of antistatic padding inserts to defend against UPS people if they decide to play football with the parcels.

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Placing the first Terminators in their boxes, oh man, what a crazy feeling.

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We are tremendously thankful for everyone's support. On the way to the UPS office, we were recalling back about three years in time to when the project got its spark in a rainy drizzle in midst of a "hey, do you recall what that Feature Connector was all about?" vintage PC chat outside a friend's garage.

If you placed an order and haven't yet received a payment link to complete the checkout, hold on a bit longer - it will probably take me a bit more than a week to get the order queue completely rolling. (I'm verifying with customs how to declare exports to all the different world areas so I don't make any mistake, so that will take a bit)

It is kind of a crazy anxious feeling to wish that the card will work well in everyone's vintage PCs. Though I don't doubt that there will be plenty of "oh why is it doing that?" moments as well with fresh pairs of eyes using it. When you do get your copy, please do have a low barrier to report any issues at https://github.com/juj/crt_terminator/issues , even if they might be "just" documentation issues or similar. I've been staring at the manual text for so long that I'm starting to zone out into that "forest from the trees" state of mind.

Reply 108 of 110, by Shponglefan

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Really excited to get this card! I know VLB support is YMMW, but I've got a half-dozen VLB motherboards and VLB cards I want to test out just to see how it works.

Can't wait for this one. 😁

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Reply 109 of 110, by Pierre32

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Congrats guys. I've been frothing for this since the first post, but currently find myself in a slightly different financial position than I was a year ago. I'm staying subbed to the thread, and looking forward to all the user reports. Could twist my arm...

Reply 110 of 110, by clb

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Shponglefan wrote on 2024-10-31, 00:09:

Really excited to get this card! I know VLB support is YMMW, but I've got a half-dozen VLB motherboards and VLB cards I want to test out just to see how it works.

Can't wait for this one. 😁

That's fantastic!

The story with our VLB testing is that I had one VLB mobo from old days but couldn't find a VLB graphics card.. got one from eBay, only to realize that the mobo I had was apparently faulty and wouldn't boot. Then decided to get another VLB capable motherboard from eBay.. that one did boot, but oddly, only with ISA graphics cards, and if I put that VLB graphics card in, the system wouldn't post. Then got another VLB graphics card from eBay, which then did boot.. but then to find out that I couldn't get that motherboard to detect any IDE devices, either via a IDE card or using XT-IDE. Argh.

At that point being so much in the red already from hunting all that VLB gear from eBay, we decided to put a lid on the VLB investigation.. there were so many other things to work on in the project (most notably to research how to get PCI SVGA adapters to work), and we had superficially been able to confirm that one VLB card would provide a picture out to get to BIOS screen at least.

Interested to hear how different VLB adapters do in practice.

Pierre32 wrote on 2024-10-31, 08:25:

Congrats guys. I've been frothing for this since the first post, but currently find myself in a slightly different financial position than I was a year ago. I'm staying subbed to the thread, and looking forward to all the user reports. Could twist my arm...

Thanks! Definitely voting to keep all arms (and other body parts) intact. Let's stay on the lookout for the reviews together, it'll be interesting content to read for sure.