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what is a z80 cpu card good for

8

84TAVeRT

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Claremore, OK
i have come to the conclusion that the extra card in my new to me XT clone is a z80 cpu card...

anyone know what it is good for?

thanks,
Chris
 
More common that you'd think.

Of course, you need the drivers to interface the PC to the board, which may be fairly difficult to come by.

If you have a V20 installed in the 8088 CPU socket, you can also run CP/M without any special cards...
 
Chuck(G) said:
More common that you'd think.

Of course, you need the drivers to interface the PC to the board, which may be fairly difficult to come by.

If you have a V20 installed in the 8088 CPU socket, you can also run CP/M without any special cards...
Click to expand...

I've heard of these CP/M cards for the PC. They were called Baby Blue (as IBM was Big Blue), and contained a Z80 with 64k of memory. They were not very popular because they cost over $1,000, and because using them was a kludge. I don't think they required any drivers, but you had to manually modify CP/M programs by adding a few header bytes to the start of the program. When the 8088 would see the header, it would pass control to the Z80.

The cards are also very timing-sensitive and only work in an 8088 PC.
 
Chuck(G) said:
If you have a V20 installed in the 8088 CPU socket, you can also run CP/M without any special cards...
Click to expand...
Can you tell something more, please?
I've got two mobos with NEC V20 and Sony CXQ70108D (second-sourced V20?), and they indeed run many programs for CP/M-80, but I've never tried running the CP/M itself, thought it's too hardware-dependent to run on a PC...
 
Marrr said:
Can you tell something more, please?
I've got two mobos with NEC V20 and Sony CXQ70108D (second-sourced V20?), and they indeed run many programs for CP/M-80, but I've never tried running the CP/M itself, thought it's too hardware-dependent to run on a PC...
Click to expand...

You can do it--but you have to write your own BIOS or use something that someone wrote to interface to the PC BIOS or DOS.

The big reason for not using "real" CP/M-80 is that at the timeframe of the V20/5150/5160, CP/M was still a viable product with an incompatible filesystem (to MS-DOS). It was simply easier and cheaper to translate CP/M calls to the appropriate MS-DOS interface and get the benefit of being able to use the DOS filesystem.

There was at least one emulator for the Z80 that created a "virtual" CP/M disk on the MS-DOS filesystem. I'll look around a bit and see if I can locate it.
 
well this card slows down my turbo xt to 4.77mhz when it is installed...

i guess i need to get a cp/m program to test it :)
 
My uncle Meoogy says, "If ask wrong question, answer not matter."

From the other thread the picture you had shows an EGA card. I never knew exactly why those RCA jacks were there as I never saw any labeled before. You can try hook the card up to a TV instead of a monitor through a "composit" connection. Other then that...EGA was the lowest color resolution system that Windows 3.1 would work on.(I think)
 
i don't think the EGA cards used a Z80bCPU chip or a 12mhz crystal...

i did find some numbers on the card...

Audio Visual Laboratories, Inc.
27122 R0I
M14A 94V0
Serial Number 1518

i know i looks like an EGA card, but it doesn't even try to initialize a monitor on the rca jacks or the 9-pin port...
 
davd_bob said:
From the other thread the picture you had shows an EGA card. I never knew exactly why those RCA jacks were there as I never saw any labeled before. You can try hook the card up to a TV instead of a monitor through a "composit" connection. Other then that...EGA was the lowest color resolution system that Windows 3.1 would work on.(I think)
Click to expand...

Two RCA jacks are pretty much standard for EGA cards--they go to the option header and nowhere else. So, unless you've got some sort of option board installed on your EGA display adapter, the RCA jacks are NC--unlike the RCA jack on a CGA.
----------------------------------
Back to the original question--there were a goodly number of co-processor cards, from Z80 to 68000 and NS32016. I think there were also Clipper and Transputer cards. Probably at least a half-dozen outfits with Z80 cards.

Let's not forget microprocessors in peripherals. You could probably port CP/M to run in the Z80 on an Adaptec 1540 SCSI adapter. I've got an Adic QIC tape drive here that uses a 6502 in the controller. Some derivative of the 6800 appears in a large number of hard disk drives. An often-neglected part of PC history...
 
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Well, *some* EGA cards (e.g. EGA Wonder) had a jumper that selected whether one of the RCA jacks connected to the feature connector or output composite video.
 
84TAVeRT said:
i don't think the EGA cards used a Z80bCPU chip or a 12mhz crystal...

i did find some numbers on the card...

Audio Visual Laboratories, Inc.
27122 R0I
M14A 94V0
Serial Number 1518

i know i looks like an EGA card, but it doesn't even try to initialize a monitor on the rca jacks or the 9-pin port...
Click to expand...

Maybe it's a soundcard?
 
I still it is a control interface for older commercial video decks. Many used a 9 pin interface in a multidrop (is that the right word) or loop setup.
 
well one chip had a piece of paper taped to it ... that said Genesis 11-4-84 i believe...

i don't even have the board... it is on its way to a new owner...
 
Sorry to necro post. I just cracked open an IBM XT from my basement and it has this same card. My Google search's brought me to this thread. It does appear to have its own ram, CTC (Clock Timer Circuits) etc. I think this came from MassMutual back in the 90's and we did have a in house TV studio so it very well could have been a control interface. It even has the same paper label "GEN 07/11/84" on U15.

http://www.stevenmichelsen.com/AVL/ <--- Should look familar
 
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mlaferriere said:
Sorry to necro post. I just cracked open an IBM XT from my basement and it has this same card. My Google search's brought me to this thread. It does appear to have its own ram, CTC (Clock Timer Circuits) etc. I think this came from MassMutual back in the 90's and we did have a in house TV studio so it very well could have been a control interface. It even has the same paper label "GEN 07/11/84" on U15.

http://www.stevenmichelsen.com/AVL/ <--- Should look familar
Click to expand...

Assuming his card was what most people hold to be a coprocessor card, and any card with an ancillary cpu is a coprocessor in the same way an 8087 is, far less commonly then not is it intended to supplant the primary micro by running a full fledged os and application s/w. I‘ve owned numerous cards that had a separate micro -z80, 8088, 80188, etc., but they didn't become a host for a different os. The IBM PGC has an 8088 and is a graphics card. What I've toyed with in my head was trying to get it to in effect become a 2nd computer within the big box. A neat hack if anything ever becomes of it. Of course this is a quite common practice today, utilizing a gpu to accomplish things the main micro can't even do.
 
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