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Thread: Powertran Cortex

  1. #71


    > The Cortex rules...

    No Wiki page - Probably should be...

    Jack (Too ignorant to take it on...)

  2. #72


    Just in case it is of use, here are the pin functions for the 74LS2001 as used in the Cortex:

    Pin 1: GRANTOUT
    Pin 2: BEN
    Pin 3:
    Pin 4: TO
    Pin 5:
    Pin 6: RESET
    Pin 7: _CLK (LCLK and BCLK tied together, so I will assume LCLK)
    Pin 8:
    Pin 9: _CLK (LCLK and BCLK tied together, so I will assume BCLK)
    Pin 10: GND
    Pin 11: TOEN
    Pin 12: GRANTIN
    Pin 13:
    Pin 14: CYEND
    Pin 15:
    Pin 16: BRQ (BRQ on Cortex Schematics)
    Pin 17: VCC
    Pin 18: READY
    Pin 19: TRACK
    Pin 20: BUSYN (TOEN on Cortex Schematics)

    The following five signals are not connected to anything in the Cortex, so I haven't got a clue which pins they belong on.

    IRQI (I will tentatively put this on Pin 3)
    BRQIN (I will tentatively put this on Pin 5)
    LOCK (I will tentatively put this on Pin 8 )
    PRBQ (I will tentatively put this on Pin 13)
    INTEN (I will tentatively put this on Pin 15)

    I probably won't find a 20-pin device I can code this into, so I might try and code it into a 32-pin PLCC with a small board to route the pins where I need them to be when they plug into the 74LS2001 socket. Useful side effect will be that I can set up a jumper pad to allow signals to be moved around if need be, especially if it turns out that this chip is useful elsewhere or if we ever come up with an implementation that needs the additional signals.

    I now also have a lot of close-up photos of the underside of the Cortex mainboard that I used to help trace everything out. I printed out the upper side on 8 A4 pages and taped them together to get a beautiful large representation of the whole board that is really easy to trace through (though there were a few small areas where the traces didn't scan as well as I'd have liked).

    Now I just need to learn how to code CPLDs. . .one task of many on my list of things to do this year.

  3. #73


    Hello All

    Crikey!, from time to time I goggle "Powertran Cortex" and just get a few hits on the ETI articles. Today I am totally floored by this thread, and the history behind the Cortex.

    I have two Cortices (Cortexes). One is a MK1 in a disassembled state, I through away its case, as I could not store it at the time of disassembly in the early 90's.

    The second is a MK2 which I built up out one the last kits to be available, all tha is missing on it is the FDD interface that I could never lay my hands on the TMS9909 IC.
    I also has a 74LS612 memory mapper chip and the simple E-Bus logic for the parallel interface and the Cortex RGB interface board (I have just now removed its cover).

    I also have a stack of documentation for it, I am willing to share it just because this hardware needs to documented and not left to disappear into the mists of time.

    As you can guess, I am a closet geek/nerd that preserves old hardware. I have tons of Transputer kit as well, even an Esprit supernode.

    By trade I am an electronic design engineer, and the Cortex is partly responsable for it

    Best Regards to all Cortex fans/users.


    PS: I would like to buy a TMS9909 and a 9938/9 ic's for my MK2 Cortex, and I'd like an image of CDOS as well.

  4. #74


    I have the missing newsletters 5 and 8 in my Cortex stuff. I'll scan them to PDF's if someone wants to post them with the others. I was missing 20 and 21

  5. #75


    and I have newsletter No1 as well, I can't count

  6. #76


    Oooohhhh! Please scan those and if you get them to me I'll put them up with the others. Note that the emulator file there has a CDOS 1.20 image. A scan of the Mark II documentation would be a good thing too, assuming it is any different from the files we already have.

    Send me a PM on the TMS9909 issue, as I do have one of those I could probably part with. They are a bit hard to find.

    Since you mentioned buying one right towards the end, any idea when Powertran stopped selling the MK II kits?

    Also, were there any ETI articles other than the ones we've put up so far? You mentioned having the kit for the 9938 mod--getting data on that one would be nice (as I have a spare 9938 that was looking for a good project--unfortunately, I only have the one).

  7. #77
    Join Date
    Jun 2009
    South Florida, USA


    I have the article for the V9938 board. I was just all 'scanned out' after doing all the other stuff. I'll get to it when I get a chance. I believe there is something in one of the User Group Newsletters that describes the mods necessary to remove the TMS9929 and interface the card in its place.

    As for the CDOS disk image, perhaps you could extract all the emulator files so it's a bit more obvious what's in there?

    I've been working on the MDEX disk images and also making slight mods to the emulator along the way (I'm doing all the disk work on the emulator to give it a run for its money!). I will send them when I can.

    I have some MDEX disks (Forth, Pascal) that don't read well on the Cortex and hence never made it to image form. I might build the improved data separator (also in one of the newsletters). If that's no good I'll have to try and capture the raw data and decode it with a software data separator...

    Good work on the '2001! I know ABEL, CUPL and couple of other languages but not done any Verilog or VHDL. I like the Atmel CPLDs.

    Welcome to Cybernaut! See, we're all coming out of the closet now!

  8. #78


    I fired up the MK2 yesterday for the first time in 14 years, I had to replace a faulty keyboard encoder ic before I could type anything into it. Seem to be working a treat

    I realised I have chucked all my old cassette decks (I unintentionally kept a few cassettes), so I have nothing to load the programs on the Cortex with. I'll have to borrow a tape deck and digitise those programs, so that I can load the Cortex from a PC sound i/f.

    I have an original glossy sales brochure for the MK2 in colour, the original ETI Digest articles, the original Powertran construction notes for the MK1 and MK2 (not much different from the ETI articles), some details on a Video inteface (not v993, details on the RGB interface, details on the E-bus parallel interface, one sheet on E-bus from an RS databook. Some sales bumpth from Powertran and uPE. The TI 9900 family databook and another book on the 9980 (I think). A photocopy of a magazine review (PCW?) and a list of benchmark times against other computers from the same period. Plus some correspondance between me and the the user group. I believe thats all I have.

    Powertran had given/sold their last remaining stock to the user group. When I bought my MK2 from the user group in March 87 for 80, they only had 3 left. A college friend wanted to build one as well but they had sold all of them by June 87.

    Crikey!, Where did I get 80 quid from in 1987 ?, I was a student..........

    I rescued the MK1 years later from a skip at the university where I was studying for my MSc, I believe it was chucked out from a robotics lab. I did go skip diving to see if the was anything else in there such as development software, but I drew a blank apart from the MK1.

    What I really need is to get the floppy interface going, and then i'll take a look at other HW projects for it (memory expansion etc). I wonder how many Cortex kits Powertran
    sold altogether, these must be the one o

    I do remember getting hold of a datasheet for a 74HC2000, but the function of that device was an optical encoder and 16 bit counter. I was thinking along the line of similarity between the 74LS612 and 74LS610, hoping the 2000 wasn't to disimilar in function to the 2001.

  9. #79


    should have left an idiot space (9938 )
    Last edited by Cybernaut; August 1st, 2009 at 09:08 PM. Reason: I could not spell idiot right, LOL

  10. #80


    On Cortex numbers, I suspect the total isn't very large at all--and the majority of them were probably sold in the Dec 1982 through early 1985 period. I figure sales probably tapered off there, just because a majority of the folks who were comfortable building their own kits would have already purchased theirs, and sales from then to the end point in June 1987 would have tapered off pretty steeply before settling into the slow sales through the User's Group. As Cortex owners were more involved types when it came to hardware, I suspect a significant portion of them were actually IN the User's Group (unlike other systems where such participation rates were in the 1-10 percent range). I read somewhere that there were between 55 and 60 members of the User's Group in 1987--so five to ten times that number is probably the range of all Cortices ever produced. Most of those were probably Mark I machines, which would make the Mark II the truly rare bird. This rarity is actually mirrored in the machines we now know about, though there are probably more machines of both types hiding in lofts. Cybernaut has the only Mark II that came out of the woodwork as a result of this thread, though TMS9995 noted that he also built one for a friend who later trashed it. (Cybernaut, could you put a picture of it up somewhere so that it can be added to the nice file on the Cortex at the Old Computer Museum?) And between the rest of us and other machines that I know of, there are at least 10 documented Mark I machines still out there. Low numbers--but not definitive, as this thread is doing a really good job of finding more Cortices. That said, the lower limit on these machines is probably in the range of 250 or so, with about 50 of those being Mark II machines; and the upper limit is probably about 600, with 100 of those being Mark II machines. I suspect that most of them haven't survived. We'll be pretty lucky if more than 20 Mark I and 5 Mark II machines turn up, though more than that will be a pleasant surprise.

    I'll upload the extracted archive of the Emulator files to WHTech later today, TMS9995. I have also found another easy means to transfer files that aren't too large--you can put them onto your LiveDrive at Hotmail and share them out to specific individuals. Good for files larger than the 10 MB you can send as an attachment, up to 100MB.

    I'll check to see which of the databooks I already have scans of, Cybernaut (most of them are on WHTech too, in one of the other directories). The Color Sales Brochure for the Mark II would be nice to get a scan of, especially if you can scan in color. Scans of the other articles would be good too (we might have the same parallel interface article you mention up already, as there are two different articles on that subject in the issues of ETI we've unearthed to date). One had a dual joystick interface as well. I don't have the foils for that one, so if it's the one you have, a photo of the underside of the board would be very useful (the top foil can be reconstructed from the picture in the magazine article). A scan of the construction manual for the Mark II, the E-bus extract, the other Video Interface, the sales bumpf, and any of your User Group correspondence that touches on the system itself would be good too, as they may have some data we don't already have.


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