640x480x16 VGA

640x350x16 EGA - same image

Z-449
Z-449 (150-0307)
SwitchType: EGA/ZDS 480 Line Mode
Controller:
Output Port(s): 15-pin analog
9-pin TTL
Compatibility: MDA, HGC, CGA, EGA, VGA
Video Memory: 256K only
Max. Video Mode Resolution: 640 x 480 x 16 - ZDS Mode
132-Column Support: No
Switches: See Below

1 2 3 4 Monitor Type
OFF OFF OFF ON 80 Column CGA
OFF ON ON OFF 350 Line EGA
OFF OFF ON OFF MDA / Hercules
OFF ON ON OFF VGA (Mode 12 only through BIOS calls)
ON ON OFF OFF VGA Monochrome (limitation as above)

Switch 5 activates automode feature. This automatically switches between EGA & CGA or MDA & Hercules under software control. As this uses NMI, it is recommended to be turned off unless specifically required.

Switch 6 switches between 9 pin TTL video connector (OFF) and 15 pin Analogue connector (ON).

Device Drivers were available for Microsoft Windows (2.0), Lotus 1-2-3, Autocad, Gem and Pagemaker to utilise ZDS 480 line mode.

Installed the card in my main 286 and can confirm its 100% EGA with a EGA-to-VGA converter at the end 😀

Some results:

EGA Game (320x200x16): Output 720x400 @ 71Hz (seems to make some upscaling here)

VGA Mode 12h (set with debug.exe): 640x480 @ 60 Hz

Boot and DOS Display: 640x350 @ 71 Hz

Compared to a standard 16-bit VGA card in another 286 PC:
Boot and DOS Display: 720x400 @ 70 Hz

...I agree its a very special card and its unlikely many other people own it... 😉

Love the card! The spare IC pads are funny. What spares would have gone there?

Oh! Now I have to find one of these cards! 🤣

I also remember that there were a number of laptops from the late 80s or early 90s that could hook up to a VGA monitor but only supported EGA.

The archive HEATH EGA.rar contains two BIOS dumps 1.32 and 1.33.
But they are identical up to the byte, this is an error, or they are the same?
I am trying to use this BIOS for card version 1.31, but it doesn't work. Do you have a BIOS for version 1.31?

Thx

I dont remember. Think I didnt compare the files, just copied both of them to have them archived. So yes, they might be identical for both card revisions.

What does your card do? Does the PC boot without picture? Or doesnt it post at all?

What size of EPROM do you use?

It is so against logic... even PS/2 MCGA had 320x200x256, that is so strange, but well they just cheaped out on a proper DAC then.

Attached photo card

What does your card do? Does the PC boot without picture? Or doesnt it post at all?

I receive a beep signal for no graphics card
I have a 1.33 card, I tested the BIOS chip on it and it works fine.

What size of EPROM do you use?

27256

There are several differences in the board layout.
But I think problem in PAL logic, they differ in firmware versions 1.31 and 1.33. Therefore, the bios is not suitable.

I dont think the reason for the malfunction is the ROM. Its the same chipset, there should be no difference in programming. There are many scratches on the backside, is any trace broken?

I wonder if they did this so they could consolidate their monitor line-up and avoid releasing models with expensive multi-sync and dual TTL/analog input capability. May have saved more money then on the monitor then the extra circuitry on the video card cost. And, VGA was right around the corner -- this let them start shipping with real VGA adapters once they had them ready.

radiounix wrote on 2020-09-03, 13:10:

I wonder if they did this so they could consolidate their monitor line-up and avoid releasing models with expensive multi-sync and dual TTL/analog input capability. May have saved more money then on the monitor then the extra circuitry on the video card cost. And, VGA was right around the corner -- this let them start shipping with real VGA adapters once they had them ready.

The cost of running a video card at different frequencies is quite minimal , back in the day you lived with whatever you had and maybe upgraded one part at a time, using the same monitor you bought years ago for a decade or more with your current pc was common.
So being able to reuse your expensive screen with a new graphics card was handy.

Also note that CGA analog monitors were a thing back then as well.

My guess is like an antique VGA card I once owned they likely could skimp on memory having only 128kb if they wanted just ega and 256k for “vga 16 color”

Has the op tested any of the multitude of 16 color 320x200 VGA games?

I never could understand the 16 color vga marketing back in the day but it was very much a thing in games at least so maybe the card was a marketing gimmick for value conscious customers.

Predator99 wrote on 2019-01-06, 18:10:

Z-449 Z-449 (150-0307) SwitchType: EGA/ZDS 480 Line Mode Controller: Output Port(s): 15-pin analog 9-pin TTL Compatibility: MDA, […]
Show full quote

Z-449
Z-449 (150-0307)
SwitchType: EGA/ZDS 480 Line Mode
Controller:
Output Port(s): 15-pin analog
9-pin TTL
Compatibility: MDA, HGC, CGA, EGA, VGA
Video Memory: 256K only
Max. Video Mode Resolution: 640 x 480 x 16 - ZDS Mode
132-Column Support: No
Switches: See Below

1 2 3 4 Monitor Type
OFF OFF OFF ON 80 Column CGA
OFF ON ON OFF 350 Line EGA
OFF OFF ON OFF MDA / Hercules
OFF ON ON OFF VGA (Mode 12 only through BIOS calls)
ON ON OFF OFF VGA Monochrome (limitation as above)

Switch 5 activates automode feature. This automatically switches between EGA & CGA or MDA & Hercules under software control. As this uses NMI, it is recommended to be turned off unless specifically required.

Where did you get these switch settings? I have a similar SIGMA DESIGNS card [but without the VGA connector], it's labelled "ERGO480", with a mystery 5-switch block that I can't figure out. My card uses the same custom L1A2334 chip (and the same set of CHIPS 82C43x EGA controller chips).

This is a strange card, it seems to want to output a video signal with a ~31.80khz hsync and it doesn't even have a 16.257Mhz crystal on board. But none of my other EGA cards are able to handle the 10Mhz clock in my Turbo XT. This card appears mostly fine, probably because it has 100ns RAM on board.

Interestingly, it has a 32K video BIOS but it's only mapped from C000-C3FF. One of the PAL16L8 chips (which is hiding underneath the BIOS chip!) implements a bank switching scheme. (Output 0x00 or 0x01 to port 3CBh to do the bank-switching magic. ) The copyright string in the BIOS looks familiar:

100000000  55 aa 20 e9 1d 09 e8 c9  0f cf e8 49 08 cf e8 6a  |U. ........I...j|
200000010  08 cf e8 0b 0d cf e8 20  0d cf 00 00 00 0d 49 42  |....... ......IB|
300000020  4d 20 45 47 41 20 43 4f  4d 50 41 54 49 42 4c 45  |M EGA COMPATIBLE|
400000030  2e 2a 55 4e 49 53 59 53  20 45 56 43 20 56 20 31  |.*UNISYS EVC V 1|
500000040  2e 36 30 20 20 0d 0a 00  20 20 28 43 29 43 6f 70  |.60  ...  (C)Cop|
600000050  79 72 69 67 68 74 20 53  69 67 6d 61 20 44 65 73  |yright Sigma Des|
700000060  69 67 6e 73 2c 20 49 6e  63 20 31 39 38 35 2c 31  |igns, Inc 1985,1|
800000070  39 38 36 0d 0a 00 00 1a  50 b0 01 ba cb 03 ee c3  |986.....P.......|

Investigations are still ongoing...

kdr wrote on 2020-10-07, 01:38:

This is a strange card, it seems to want to output a video signal with a ~31.80khz hsync and it doesn't even have a 16.257Mhz crystal on board. But none of my other EGA cards are able to handle the 10Mhz clock in my Turbo XT. This card appears mostly fine, probably because it has 100ns RAM on board.

Well, it still has a 32.000MHz crystal, and if you divide that by two, you get close enough to 16.257. So the hardware might be able to generate timings an EGA monitor can sync to. But 31.8kHz sounds like a 480 line mode, which is not that surprising on a card called "Ergo 480".

I dont remember where I got the settings from thats because I copied them here ;.)

This seems to be your card:
https://books.google.de/books?id=gC-DsOtl2MgC … 0jumper&f=false

Can you copy your BIOS here pleas? Thanks!
EGA Video cards - BIOS image collection

kdr wrote on 2020-10-07, 01:38:

But none of my other EGA cards are able to handle the 10Mhz clock in my Turbo XT. This card appears mostly fine, probably because it has 100ns RAM on board.

Im my Turbo XT, a DTK PIM TB10 clone, a Genoa-based Super EGA ("EXPERT TOP SEGA 800" according to the silkscreen, "EXPERT SEGA V3.11-5C" on the BIOS sticker, FCC ID DXL91ILLH6392. It supports up to 800 lines) works perfectly in turbo mode. That board adds a wait-state for memory access in 10MHz mode, though. Memory access (all addresses) in 4.77MHz mode uses four clock cycles, which is the 8088/V20 minimum, whereas in 10MHz mode, non-onbard-RAM memory access takes five clock cycles, resulting in a theretical maximum rate of 2MB/s on the XT bus and 2.5MB/s on the onboard RAM. You can get close to those rates using REP STOSW on a V20 processor, that's how I measured it.

Predator99 wrote on 2020-10-07, 06:42:

This seems to be your card:
https://books.google.de/books?id=gC-DsOtl2MgC … 0jumper&f=false

Nice find! Yes that is quite similar to my card, including the fact that it has five switches.

I will upload the BIOS for this card and also one other Sigma card, the SPEGASYNC [EDIT: seems that card has already been posted, but my BIOS chip is different!]. Both of these cards were produced by Sigma for UNISYS and appear to be slight variants of whatever Sigma was selling in the retail channel.

kdr wrote on 2020-10-07, 01:38:

Where did you get these switch settings? I have a similar SIGMA DESIGNS card [but without the VGA connector], it's labelled "ERGO480", with a mystery 5-switch block that I can't figure out. My card uses the same custom L1A2334 chip (and the same set of CHIPS 82C43x EGA controller chips).

Four of the five switches seem to be plain EGA switches with their well-known meaning, but the card adds two new combinations in addition to the standard EGA configurations:

1OFF OFF  ON  ON - EGA in MDA compatibility mode with 480 line monitor, possibly CGA with 80 columns as secondary card
2OFF OFF  ON OFF - EGA with 480 line color monitor, possibly MDA as secondary card

keropi wrote on 2019-01-07, 21:22:

Oh! Now I have to find one of these cards! 🤣

Looks like a number of these boards went up for sale on a major auction site recently.