VOGONS


Arrived ISA 8 bit RTVGA boards

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First post, by Dimitri

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didn't tested yet.
rtvga8.png
DYI IC only kit with DSUB15 and keystone bracket available.

Reply 5 of 32, by Grzyb

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Now, which is better: this Realtek card, or that Trident one by Sergey Kiselev / Monotech...
With 8-bit ISA graphics, probably the most important feature is CGA compatibility.
So, note to self: find some cards based on RTG3105 and TVGA9000, and run CGA_COMP on them!

Reply 7 of 32, by GigAHerZ

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Damn, it's weird to look at boards that have those soviet era resistors here and there. 😁

Amazing work! (Y)

"640K ought to be enough for anybody." - And i intend to get every last bit out of it even after loading every damn driver!

Reply 8 of 32, by Cyberdyne

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I love soviet era resistors, they have numbered values printed on them, no color codes.... 😊

I am aroused about any X86 stuff that has full functional ISA stuff. I think i have problem.

Reply 9 of 32, by HanJammer

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Grzyb wrote:

Now, which is better: this Realtek card, or that Trident one by Sergey Kiselev / Monotech...
With 8-bit ISA graphics, probably the most important feature is CGA compatibility.
So, note to self: find some cards based on RTG3105 and TVGA9000, and run CGA_COMP on them!

Realtek having less pins is better - easier to mount, and takes less space on the PCB ;]

Feature wise they should be pretty similar although there was no better card than Trident 9000 in this price range.

But it doesn't matter at all in the XT and using it in anything better than XT makes no sense (not that it makes whole lot of sense in XT - most 16 bit ISA graphic cards will work in 8 bit slot, and those Trident 9000 cards are readly available and cost like what, 5 Euro at most?).

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Reply 10 of 32, by Grzyb

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HanJammer wrote:

Realtek having less pins is better - easier to mount, and takes less space on the PCB ;]

Indeed, especially considering that it has integrated ROM BIOS, while Tridents need a separate chip for that.
But there's something wrong with this particular BIOS: it only detects 256 KB of DRAM, while the board has 512 KB.

Reply 12 of 32, by matze79

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Yeah the SuperSlow RTVGA 😁

What does it cost ? 😀

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Reply 13 of 32, by spark2k06

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Dimitri wrote:

I have Trident boards and ICs, will do test later, need to solder Trident board.

With Trident board, don't forget to run the SVM89.EXE utility before, which allows you to enable the CGA compatibility mode:

https://www.youtube.com/watch?v=hhkDeO8pLZg

Reply 16 of 32, by Grzyb

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georgel wrote:

I don't think any VGA card requires additional utilities to provide CGA/EGA modes. They are just subset of the VGA spec.

Generic VGA only offers basic compatibility with CGA modes, far from enough for those interested in playing CGA games.
CGA games, when run on a VGA, tend to exhibit various problems, ranging from wrong pallete to not working at all.

So, when considering a VGA for PC/XT, it's very important to choose one with special CGA compatibility mode - which is chipset-specific, hence the need for additional utilities.

Reply 18 of 32, by Grzyb

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Grzyb wrote:

Now, which is better: this Realtek card, or that Trident one by Sergey Kiselev / Monotech...
With 8-bit ISA graphics, probably the most important feature is CGA compatibility.
So, note to self: find some cards based on RTG3105 and TVGA9000, and run CGA_COMP on them!

So I did some tests...
Unfortunately, I don't have anything with RTG3105, so I used a card with similar Realtek chipset - I doubt there are any differences between them in terms of compatibility.

Tested cards:

Realtek
RTG3103
256 KB RAM
8-bit ISA
CGA/Hercules modes set using VMODE.EXE

Trident
TVGA9000i-1
512 KB RAM
16-bit ISA
CGA/Hercules modes set using SVM.EXE

Both running in a Celeron 266 machine, with a typical CRT SVGA monitor.

CGA compatibility tested using: CGA_COMP 1.26.1, Digger, J-Bird, Round 42
Hercules compatibility tested using: MODETEST.EXE from Pizazz Plus 2.0, Blockout, Spacewar (all using standard 720x348 mode), Tunnels of Armageddon (using non-standard 640x300 mode)

The results... surprisingly similar for both chipsets!
The following problems have been found in both:

* Uniformity and Convergence - monitor goes into power saving mode, well, actually as expected
* Border/Overscan color - there's only 8 colors
* Top-and-bottom dual line cursor - no cursor
* Strikethrough cursor - no cursor
* CGA Snow - doesn't work, of course
* Interlaced video mode - doesn't work, of course
* Display Positioning - sometimes blank screen or loses sync
* Start Address reprogramming - some garbage during scrolling vertically
* Composite - doesn't work, of course

Also, both cards have the "Load game"/"Warm boot" feature in their utility programs, supposed to reboot in CGA mode, for running "booter" games - but it failed, both cards reboot in VGA mode, I suspect the machine may be too modern and performs cold boot instead of warm boot.

I've found some differences between the two cards, most of them totally unimportant:

* Vertical retrace - Realtek 59.6 Hz, Trident 60.3 Hz, so both pretty much CGA compatible
* different results of Video RAM Speed Benchmark - expected, of course
* different set of supported SVGA modes - expected, of course
* Realtek always boots in color, Trident - sometimes in color, sometimes in monochrome, ie. the well-known issue with DDC monitors, easily remedied with SMONITOR.EXE or some hardware workaround, and very likely resolved in all those modern cards

The only important difference was with Tunnels of Armageddon running in Hercules mode:

* Realtek - monitor loses sync
* Trident - OK

So, Trident wins.
By a very narrow margin.