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The Compact Computer 40 (CC40)


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I'll have to do some digging, as I know Michael Becker did one when he replicated it back around 1990. I need to look at the stuff I got from @Acadiel again, as he had some of Michael's HexBus projects in the group of items I bought from him. I do have the manual for it (and I'll take a look to see if that folder has the schematic too). The functional spec for the HexBus interface is on WHT, it is just not an intuitive find.

 

I have the schematic for the floppy controller. :)

HX5102M.pdf

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Finally had a chance to watch the video. Super excited about this development, and so glad Jim was right across from me at VCF-SE to talk about it!

 

Once we get the handful of folks with programs (Ksarul's Quickdisk archives, for example), we can make a master archive of existing CC-40 programs. Since I was also able to dump about all the cartridges as well, we can probably get a multicart made, too, that has all the CC-40 cartridges on it. Helocast has a nice PCB already laid out that we can adapt to an EPROM setting and maybe put a slider switch onboard (unless someone wants to write the assembly code to select/launch the cart without a switch.)

 

Now that the protocol is understood and Jim has a working example, we can probably easily attach an Arduino Uno to the Hexbus port and further use it for serial communication, experimentation with the CC-40 console, etc.

 

Thanks again for your hard work, Jim!

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Hey Jim - one change if you can swing it... can you put a Hexbus pass through? The RS232 and other peripherals have one so you can daisy chain devices. Thoughts?

Probably not in this iteration, as it'll push the board size a fair bit, and this is a prototype board. I will, though, put a passthrough on the production board.

 

Jim

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Realize the conversation is primarily Hex-bus, but couldn't find topic. Apologies in advance - not stealing thread.

Here's the PCB basics for all 32K CC40 carts (Express PCB) for those that don't want to start from scratch and haven't jumped to KiCad.

Obvs no EEPROMs pin compatible with the mask rom, but it won't take much effort to sub a programmed AT49F040 + dip switch block to store/select multiple 32K images instead. There's room.

 

attachicon.gifCC40cart.JPG

attachicon.gifSS3007.JPG

 

I'll update with progress if it doesn't become one of my many hardware projects I have in the pipe. :-o

 

Here's a 16 bank 32kB multi-cart switcher (simple design), based on the above, using 32 pin JEDEC FLASH, EEPROM, or EPROM. EAGLE lbr files available as well.

 

Jim

post-29128-0-81100500-1509262321.png

post-29128-0-02230500-1509262327_thumb.png

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This turned out as such a great thread. Jim, it seems you did some marvelous job and progress. congrats :)

The youtube video has some CGA colour touch, which somehow fits the retro topic.

 

I agree with Jon that a pass through would make the device more useful.

If we are talking wishes for the production, all Hex-Bus Devices share the same design for their cases, therefore follow a certain pattern for the PCB.

http://www.ti99.eu/?page_id=1555&lang=en

This would allow people to make 3d prints of cases in the Hex-Bus typical style.

 

Am I right, that with this Device there is no DSR involved?

 

Many thanks for your effort, Klaus

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This turned out as such a great thread. Jim, it seems you did some marvelous job and progress. congrats :)

The youtube video has some CGA colour touch, which somehow fits the retro topic.

 

I agree with Jon that a pass through would make the device more useful.

If we are talking wishes for the production, all Hex-Bus Devices share the same design for their cases, therefore follow a certain pattern for the PCB.

http://www.ti99.eu/?page_id=1555&lang=en

This would allow people to make 3d prints of cases in the Hex-Bus typical style.

 

Am I right, that with this Device there is no DSR involved?

 

Many thanks for your effort, Klaus

Thanks.

 

Yeah, not sure what was going on. I re-recorded it with better color, but I have not made it public. Oh well.

 

I am all for a Pass-thru on the prod boards, but to get it and keep the size down, I need to go to SMT parts. For the prototype (I'll probably grab 5 boards), I wanted to keep board costs down. I also need to test out my ideas to switch things to 3V0 power only, to save on batteries and the 5V regulator. I figured testers can put it at the end of their chain...

 

I'd want to debate the desire for a common case design. The production board will probably be 2" square, maybe even 1" square if I can stak the Hex bus connectors on both sides of the board. The std case PCB is probably 25 suare inches. Are you sure you want such a big PCB when most of it will be unused? I would think someone could design a Hex Bus sized case with a small place for the PCB in it.

 

Yes, there is no DSR needed, and in fact, no DSR can be used. The entire functionality is emulated inside the AVR.

 

Jim

Edited by brain
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Here's a 16 bank 32kB multi-cart switcher (simple design), based on the above, using 32 pin JEDEC FLASH, EEPROM, or EPROM. EAGLE lbr files available as well.

 

Jim

WOW! Thank you very much, Jim - very professional! I got sidetracked trying my hand at upgrading my CC40's internal memory. So like all my "ideas" I never get back to them until months later.

Doug

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WOW! Thank you very much, Jim - very professional! I got sidetracked trying my hand at upgrading my CC40's internal memory. So like all my "ideas" I never get back to them until months later.

Doug

No problem. I'll put the EAGLE CAD files on github and folks can convert to KiCAD or whatever (or use the free v7 EAGLE to view/print).

 

Did TI indeed tie !CRAM and !CROM together in the cart? That seems like a major no-no... (unless those lines are open collector)

 

Jim

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Here's a 16 bank 32kB multi-cart switcher (simple design), based on the above, using 32 pin JEDEC FLASH, EEPROM, or EPROM. EAGLE lbr files available as well.

 

Jim

We can fit every CC-40 cart into this.... plus room for more.

 

Anyone making one, let me know and I’ll try and concatenate the binaries that I have and test it.

 

Haha, you’re on a roll, Jim!

 

We can probably talk about the Hexbus display adapter next :-)

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I'll run a batch of 10 boards, as I am readying a PCB order. But, I need to ensure the design is solid. Waiting on helocast to reply, to know if he copied his design from an official cart or not. Also, anyone have a 32kB RAM cart I can borrow to figure out how it works?

 

If the proto works, next step is to shrink the design using a 1MB flash ROM, a small CPLD (to allow programming it from the cc40), and some RAM. I notice a Address line 15 is on the bus, and I wonder if one can simply put the required 16 kB of RAM on the cart port and not have to "upgrade the motherboard" to add in more RAM.

 

Any device is pretty easy now (refactored the hexbus protocol stuff into a separate source file), and I have a small 320x240 lcd panel here... You looking for anything in particular?

 

Jim

Edited by brain
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No problem. I'll put the EAGLE CAD files on github and folks can convert to KiCAD or whatever (or use the free v7 EAGLE to view/print).

 

Did TI indeed tie !CRAM and !CROM together in the cart? That seems like a major no-no... (unless those lines are open collector)

 

Jim

They did, which I thought strange and I probably should have posted the other pic to help answer questions.

Of course THAT makes the assumptions Dan Eicher, A Compendium of CC-40 Information has labeling correct and also me following the traces to destination.

I apologize for adding uncertainty into the mix - my photo skills are lacking.

post-48993-0-45473000-1509297124_thumb.png

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Any device is pretty easy now (refactored the hexbus protocol stuff into a separate source file), and I have a small 320x240 lcd panel here... You looking for anything in particular?

 

Jim

 

I think Jon meant the Hex-Bus Display Interface.

 

Find it specified from page 153 here:

ftp://ftp.whtech.com/hexbus_cc40_ti74/Hex-Bus%20Specifications.pdf

 

It allowed any Computer running a Hex-Bus Interface (CC-40, 99/2,...) to connect to an external display screen.

From the TI lab prototyping back then only one or two devices are known to still exist (but none in contact with the active community).

And in the 80s/90s the interface was reimplemented by Michael Becker from SNUG, but no production run was made.

 

I don't know if it is known but the Intelligent Bus from the TI-74 and TI-95 is electrically compatible with the Hex-Bus.

So I wonder how difficult would be an mass produced adapter from one to the other.

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Thanks for the update. Looks like I need to make a few alterations. It looks like the PCB has "ears". What is the max size of the space in the cart case for a PCB (or, what are the outside dimensions of those ears?)

I had to borrow a micrometer weeks ago so I can't get you exact "ear" measurements now.

The 1.5"x1.7" ExpressPCB original are exact dimensions which JUST drop into cart plastic half.

The "ears" are functional in that they do fit four case notches but I thought the "ears" were just residue from TI's fab paneling of multiple carts on a huge piece of FR4.

I also assumed that anyone trying to make a 3D case would just size to board's dimensions w/o notches or use the two TI circuit mount/test/index holes on opposing corners on raised posts of a 3D design to minimize movement in shell.¯\_(ツ)_/¯

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post-48993-0-89775700-1509301250_thumb.jpg

Edited by helocast
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No worries (thanks for the pics), but if you get access to a micrometer, here are some items that it would be nice to nail down:

 

  • distance from ear edge to ear edge
  • width of ears at smallest
  • width of ears at widest
  • width of "pad" for edge connector (I used .035 from the cc40 tech letter, but it seems just a hair too wide)
  • length of "pad" (tech letter had .4", but that was too long when I placed it into your PCB specs (the fingers extended into the main part of the PCB), so I backed it off to .3", which seems to match your pics...)
  • How far pad (long dimension) is away from the edge of board (it looks like they are within .005 of the edge of the board, but not sure). Not hugely critical, but always nice)
  • distance between edge of last pad, and edge of board (I think I have this one nailed down, since you measured the width of the overall connector), but always nice to have a double measurement)

Jim

Edited by brain
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I think Jon meant the Hex-Bus Display Interface.

 

Find it specified from page 153 here:

ftp://ftp.whtech.com/hexbus_cc40_ti74/Hex-Bus%20Specifications.pdf

 

It allowed any Computer running a Hex-Bus Interface (CC-40, 99/2,...) to connect to an external display screen.

From the TI lab prototyping back then only one or two devices are known to still exist (but none in contact with the active community).

And in the 80s/90s the interface was reimplemented by Michael Becker from SNUG, but no production run was made.

 

I don't know if it is known but the Intelligent Bus from the TI-74 and TI-95 is electrically compatible with the Hex-Bus.

So I wonder how difficult would be an mass produced adapter from one to the other.

 

Yeah, I saw the writeup in the spec. Mainly, I was wondering if it makes sense to do output to a TV, or just do an LCD output. I guess TV (or VGA) would be of value.

 

And, yes, converting from HexBus to DockBus is trivial, just some wiring.

 

Jim

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