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CMC International Super System II

E

Endersending

Experienced Member
Joined
Mar 14, 2023
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119
Location
Walker, Minnesota
I bought some more stuff I shouldn't have on ebay. It's a CMC International System II. I can find very little information about it. It has a Z80 processor and runs CP/M. I wanted to post about it and if anyone has any information about the computer, software or company pertaining to this machine I would love to hear about it.
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CMC International appears to have been a reseller, so the system that you have was probably sold under a different name at some time. Consider that PDF page 151 shows them selling Toshiba boxes. It is interesting to see a Z80 machine using an 8257 DMAC, probably to service the 8275 CRTC. Makes me think that there's another CPU/MCU in that unit for driving the display--and that the computer stuff was just added in to an already existing terminal product.
 
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In this issue of Interface Age, you can see another CMC ad on PDF page 101. Note that those displays are terminals--the CPU is built into the deskj.

In a like vein, see PDF page 133, lower left corner. Note the Intertec Intertube? Looks just like the Superbrain, doesn't it? Just appears to be missing the floppy drives.

This was a common approach back in the day to rush a CP/M system to the market. One already likely had an x80 CPU in the terminal, so add more memory and disk support and use the same tooling that you used for terminals, thus drastically cutting development costs.

IIRC, Visual also did the same thing, as did TVI.
 
This is all great information. It will be a few days before I can fire the machine up. the previous owner has already powered it on and I don't see any RIFA caps on the machine. A few plastic risers that hold the hard disk controller broke so I need to figure that out.
From all the information I have seen it seems that CPM 2.2 is my best shot. I don't think the machine can boot off the hard disk.
What is the chance the disks from a Intertec SuperBrain would work to boot this machine?
 
Unfortunately, the probability is not very good. We need a lot more information to get to the point where we can figure out how to boot the thing. However, 22Disk does have a definition for a CMC Supersystem 2--and I haven't checked to see if I have a sample diskette. So perhaps not a lost cause yet.
 
Is there a guide or playbook on how to do this? I assume this isn't the first system to not have the correct disks.
I would imagine it would entail figuring out where addresses for video, floppy controller, etc are but how do you do that? A logic probe?
What tools (software) do I need to look at Z80 assembly or machine code using linux or dos?
Maybe a tutorial from a different machine but same concept I can learn/research about.
I will keep reading and try to get the machine ready to work on soon.
 
Well, the thing obviously has a boot PROM of some sort; you can image that and then work from there. Be prepared for a lot of head-scratching. A hardware manual for the system would help, but that's likely even harder to find than a boot floppy. Perhaps there's something on the hard disk...
 
I would like to say that this has really been a great experience for me. I plan on updating my profile with some background information about my knowledge of computers. To be short I have worked on PC's for a long time and computers have always fascinated me and the S-100 and vintage type computers are a new adventure for me and I will do everything I can to make this a fruitful journey. I know C,C++ and web languages but I am still new to address spaces, assembly, machine code and the point at which hardware and software work together.
With that being said I will look into dumping the ROM.
I will get pictures and lists of ICs
Thanks for the help.
 
Attached are the 2 ROMs that have been dumped.
The ROM with something in it was ran through z80dasm and so the asm is also in the zip.
The one at the outside edge of the board seems to be empty or not working. The other (inner) chip is half full.
I will do some more work and report.
Maybe someone can look at the code and give me a little story about what is going on. I am very green to ASM so it will take me awhile to start to decipher it.

I have also removed the Z80 CPU and used it in another computer. It works fine. I also used an oscilloscope and probed the data bus, clock and a few other chips and everything seems to be busy at reset and then it seems to stop like it is not finding its next stop to run code from.
The keyboard light blinks at startup and you can see bits moving on the bus back to the main board.
I have known good floppy drives hooked up but nothing happens with them. no motor or lights. I do not have the screen hooked up as I am testing so I am not sure if anything is showing up on the screen.
 

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  • CMC.zip
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I am not fluent in ASM but having some people look at the code they think it is corrupt.
Does anyone have a recommendation of a z80 monitor that will fit on a 2716 (2k) chip and has code I can start changing to fit this machine?
 
Over the last few days I have been researching on where this CMC International company came from.
I have been seeing advertisement with CMC selling Winchester harddisks for Porchse cars. I have also noticed most ads that have CMC also have the Intertec SuperBrain and then the CMC SuperFive, SuperTen and Super20. I also found some Floppy disks on ebay marked "CMC TARGA Operating System" Version 2.02B for CP/M 2.2, 10-1 config for SD II. Makes me feel like the CMC Super System II is a cousin of the Super Brain. I could imagine the conversation on making that deal:
"Here is what I want to do. I wanna take your extra Super Brains that are not selling as well as you want and we will call then the super system. and then put 'II' after it so it sounds new. We will slap our name on it and peddle it to dealers in the area"
Although the SuperBrain and SuperSystem are very different on the inside but that is just changing the keyboard/cpu design of the SB into 2 boards, which I think would be cheaper and easier to built then having a mechanical keyboard stuck to the motherboard.

How are CMC, Targo, Intertec and even Porsche Connected?
I feel like CMC never built computers or anything, they just did marketing kinda like how Costco has brands which are rebrands of other things.
If this is true then who built the computer and who built the boot ROM (which is what I really need). I have been learning as much as I can about assembly code, how z80 systems boot with the goal of making this computer boot.

I also found there is a Z80 in circuit emulator. From what I have found the guy doesn't sell them anymore but the parts are available. Has anyone had experience with these ICE devices, would that be an option I should consider?

Attached is a snip from a newsletter talking about using CMC parts to upgrade superbrains
 

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  • mag_10.pdf
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Another update:
I was going to try to write a ROM chip when I was noticing I could not read the chip (2716) properly at 5 volts. After realizing this I re-read the ROM at 6.5 volts for the CMC and got a good reading.
Now if the computer is inputting 5volts which is not enough to read the chip, could the chip be bad in a way that it takes more voltage to read it?
Attached is the image that looks good. Let me know what you think about the voltage problem. I have not dealt with these chips enough to know if this is common.
 

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  • CMC_2716_inner_3.BIN.zip
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It's an Intel chip. When reading Vpp = Vcc.
I tried testing the board assuming it will spin the floppy drive if it loads. The voltage for the board was 5.6 volts. I bent the Vcc pin out and put 6.5 volts to it but did not see a change it floppy drive action. I can't image I need to pull Vpp from 5.6 to 6.5 for the read. edit: I tried, Vpp to 6.5v didn't matter
I erased the other chip thinking it was empty, this was before I realized the voltage thing. I hope that chip was empty and it wasn't the character Rom for the video.
 
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I am seeking some advice:
I have not been able to get very far with this machine. My next step is to make or buy some type of Z80 Probe.

My first idea is to make something similar to a JADE bus probe where it is essentially LEDs telling my what each pin is doing. I would essentially make a socket that the Z80 sits in and taps into all of its pins.

The second Idea would be to build the same thing but with a circuit to step the clock one step at a time, and possibly add a microcontroller that could inject instructions or save the stream of bits to analyze.

The 3rd option would be to solder a bunch of LEDs to the board so I can see what the pins are doing. this would be messy and I really don't want to modify the original motherboard.

Maybe if there is another options someone has a recommendation to try. I would like to be able to visually see what the board is doing. I assume the only reason it does not boot is a bad chip or solder joint or something simple.

Thanks for the help.
 
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