VOGONS


First post, by Nvm1

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I received a lot of cards and motherboards and between them this card came up:

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8 Bit ACU MoS AVC1 9040
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It is a 8 bit ISA CGA card as far as I can see. I cannot find a single reference to the ACU MoS AVC1 9040 or any other thing written on this thing.
Some more pics:

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Detail Front 8 Bit ACU MoS AVC1 9040
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Rear 8 Bit ACU MoS AVC1 9040
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Detail rear 8 Bit ACU MoS AVC1 9040
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It has a 9 pin monitor connector, the name "dual display adapter" on the back and 2 pieces of memory (64kb?)
The silkscreen gives options for CGA/MDA/RGB/MONO and internal or external rom although there is no rom on the card itself.
I know ACU MoS from early Cirrus Logic cards but more not.

What is this card?

Reply 3 of 8, by Jo22

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I assume it's some sort of graphics card. 😀

The ROM thing could be intended for holding a regional font..
I only know of this feature from Hercules clones so far.

Maybe it was intended as a pure secondary card ?
Secondary cards sometimes have got the ability to ignore some memory
locations used by the main card (like CGA's. if a real CGA is intalled).

In DOS, someone could toggle between them using MODE CO40 CO80 or MODE MONO.
Anyway, that's just pure speculation.

Sorry, my memory is lacking a bit. But I believe I heard the Hercules Color Card (!=Hercules InColor Card)
and Hercules Monochrome Card had such a relationship. so they could coexist in the same PC.

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//

Reply 4 of 8, by Scali

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Jo22 wrote:

Sorry, my memory is lacking a bit. But I believe I heard the Hercules Color Card (!=Hercules InColor Card)
and Hercules Monochrome Card had such a relationship. so they could coexist in the same PC.

Yes, CGA and MDA were originally designed to co-exist in the same system. MDA had a 4k framebuffer at segment B000h, and CGA had a 16k framebuffer at B800h.
This places them 8000h bytes apart, or 32k.
The Hercules card was designed as an MDA clone, but with 64k of memory instead of just 4k, at B000h. This meant that the second 32k would collide with a CGA card.
So Hercules designed the memory to work in 2 pages, where the second page was disabled by default. So it starts out as a 32k MDA clone, which can work alongside a CGA card (or clone).
You can enable the second 32k from code, by writing the proper value to the MODE_CONTROL register, to use the full Hercules card. Of course that only worked when there was no other hardware at B800h.

http://scalibq.wordpress.com/just-keeping-it- … ro-programming/

Reply 5 of 8, by Nvm1

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So in short: it is a CGA clone with some options to go MDA and switch between mono and color.
It looks like a really empty card compared to other old cards I have which made me wonder. 🤣
Will look this evening if I can find a fcc id.

Reply 6 of 8, by Scali

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Nvm1 wrote:

It looks like a really empty card compared to other old cards I have which made me wonder. 🤣

Well, an ATi Small Wonder or Paradise PVC4 is also quite empty:
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video005.jpg

Both these cards are CGA+Hercules compatible. This card might be as well (they wouldn't use the name 'Hercules' since it's trademarked).

http://scalibq.wordpress.com/just-keeping-it- … ro-programming/

Reply 7 of 8, by Jo22

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Cool! So many CGA/MDA chipsets.. 😁 I wonder, is there a CGA Compatibility tester ?

I mean, one that does test for Plantronics modes, as well ?
From what I heard, while reading several data sheets, is, that this mode was often supported "secretly" (as in silently, on a side note).

Similar to other modes, like Olvetti. Olivetti was so popular, that it was supported across several
chipsets and Amiga "PC bridgeboards", Atari ST PC emulator cards. And by MS QuickBasic, even !

http://www.hampa.ch/pce/pics-ibmpc-apps.html
http://www.seasip.info/VintagePC/plantronics.html

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Screen 4 (Olivetti) - QB45
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Plantronics 4colour mode, 640x200
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"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//

Reply 8 of 8, by Scali

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Jo22 wrote:

I mean, one that does test for Plantronics modes, as well ?
From what I heard, while reading several data sheets, is, that this mode was often supported "secretly" (as in silently, on a side note).

I don't know... What I do know is that the utilities with the ATi Small Wonder have some Plantronics tests, so you could use those (both the Small Wonder and the PVC4 support Plantronics).

http://scalibq.wordpress.com/just-keeping-it- … ro-programming/