Forum Rules and Etiquette

Our mission ...

This forum is part of our mission to promote the preservation of vintage computers through education and outreach. (In real life we also run events and have a museum.) We encourage you to join us, participate, share your knowledge, and enjoy.

This forum has been around in this format for over 15 years. These rules and guidelines help us maintain a healthy and active community, and we moderate the forum to keep things on track. Please familiarize yourself with these rules and guidelines.

Rule 1: Remain civil and respectful

There are several hundred people who actively participate here. People come from all different backgrounds and will have different ways of seeing things. You will not agree with everything you read here. Back-and-forth discussions are fine but do not cross the line into rude or disrespectful behavior.

Conduct yourself as you would at any other place where people come together in person to discuss their hobby. If you wouldn't say something to somebody in person, then you probably should not be writing it here.

This should be obvious but, just in case: profanity, threats, slurs against any group (sexual, racial, gender, etc.) will not be tolerated.

Rule 2: Stay close to the original topic being discussed
  • If you are starting a new thread choose a reasonable sub-forum to start your thread. (If you choose incorrectly don't worry, we can fix that.)
  • If you are responding to a thread, stay on topic - the original poster was trying to achieve something. You can always start a new thread instead of potentially "hijacking" an existing thread.

Rule 3: Contribute something meaningful

To put things in engineering terms, we value a high signal to noise ratio. Coming here should not be a waste of time.
  • This is not a chat room. If you are taking less than 30 seconds to make a post then you are probably doing something wrong. A post should be on topic, clear, and contribute something meaningful to the discussion. If people read your posts and feel that their time as been wasted, they will stop reading your posts. Worse yet, they will stop visiting and we'll lose their experience and contributions.
  • Do not bump threads.
  • Do not "necro-post" unless you are following up to a specific person on a specific thread. And even then, that person may have moved on. Just start a new thread for your related topic.
  • Use the Private Message system for posts that are targeted at a specific person.

Rule 4: "PM Sent!" messages (or, how to use the Private Message system)

This forum has a private message feature that we want people to use for messages that are not of general interest to other members.

In short, if you are going to reply to a thread and that reply is targeted to a specific individual and not of interest to anybody else (either now or in the future) then send a private message instead.

Here are some obvious examples of when you should not reply to a thread and use the PM system instead:
  • "PM Sent!": Do not tell the rest of us that you sent a PM ... the forum software will tell the other person that they have a PM waiting.
  • "How much is shipping to ....": This is a very specific and directed question that is not of interest to anybody else.

Why do we have this policy? Sending a "PM Sent!" type message basically wastes everybody else's time by making them having to scroll past a post in a thread that looks to be updated, when the update is not meaningful. And the person you are sending the PM to will be notified by the forum software that they have a message waiting for them. Look up at the top near the right edge where it says 'Notifications' ... if you have a PM waiting, it will tell you there.

Rule 5: Copyright and other legal issues

We are here to discuss vintage computing, so discussing software, books, and other intellectual property that is on-topic is fine. We don't want people using these forums to discuss or enable copyright violations or other things that are against the law; whether you agree with the law or not is irrelevant. Do not use our resources for something that is legally or morally questionable.

Our discussions here generally fall under "fair use." Telling people how to pirate a software title is an example of something that is not allowable here.

Reporting problematic posts

If you see spam, a wildly off-topic post, or something abusive or illegal please report the thread by clicking on the "Report Post" icon. (It looks like an exclamation point in a triangle and it is available under every post.) This send a notification to all of the moderators, so somebody will see it and deal with it.

If you are unsure you may consider sending a private message to a moderator instead.

New user moderation

New users are directly moderated so that we can weed spammers out early. This means that for your first 10 posts you will have some delay before they are seen. We understand this can be disruptive to the flow of conversation and we try to keep up with our new user moderation duties to avoid undue inconvenience. Please do not make duplicate posts, extra posts to bump your post count, or ask the moderators to expedite this process; 10 moderated posts will go by quickly.

New users also have a smaller personal message inbox limit and are rate limited when sending PMs to other users.

Other suggestions
  • Use Google, books, or other definitive sources. There is a lot of information out there.
  • Don't make people guess at what you are trying to say; we are not mind readers. Be clear and concise.
  • Spelling and grammar are not rated, but they do make a post easier to read.
See more
See less

Powertran Cortex

  • Filter
  • Time
  • Show
Clear All
new posts

    Originally posted by Ksarul View Post
    I've got the complete internal logic for the 74LS2001--just not a bullet-proof identification of which pin each of those signals need to reside on. Some of it isn't used on the Cortex, which is why I was hoping someone had the signal listing for what belonged on which pin on the chip. With the signal name to actually designated pin position, I can design and program a true replacement for it. . .and then it will be around again. As a side note, there appear to be about 300 of them somewhere in Poland, assuming that they really are the same IC. . .I haven't gotten a response yet from the company that says they have them though, so they may be vaporware.

    I'm glad you liked the inclusion of the cover. I have the Aug 1984 issue as well, I just need to finish the scans for it. It contains the rest of the Jun 1984 article along with the board layout for the parallel board.
    That's interesting you've got the internals. Tony's post of the E-Bus arbiter has a couple of signals missing (TO & TO EN) and you say yours has got more than the Cortex uses. May be there were 'levels' of arbitration, depending upon the system complexity? Anyway, care to post it for reference?


      I put a copy of the patent data up on WHTech--diagrams 11a-11c are the Arbiter logic, effectively the 72LS2001 once I know the pin positions.

      I also just uploaded the ROM source and dumps of the ROMs
      Enter My Mind At Your Own Risk!


        Originally posted by Ksarul View Post
        I put a copy of the patent data up on WHTech--diagrams 11a-11c are the Arbiter logic, effectively the 72LS2001 once I know the pin positions.

        I also just uploaded the ROM source and dumps of the ROMs
        I just had a quick look - that thing is as complicated as the Cortex! May be just implement Tony's from the E-Bus book and add in the Time Out Enable and Interrupt function


          Originally posted by tms9995 View Post
          I just had a quick look - that thing is as complicated as the Cortex! May be just implement Tony's from the E-Bus book and add in the Time Out Enable and Interrupt function
          Went back in and took another look. I guess it's not that bad, but that's definitely the elusive 2001! It has 18 signal pins plus 2 power which is 20 and the Cortex PCB was designed for a 20 pin device! Awesome! Not sure if you can get a 20 pin PAL/GAL/CPLD with that number of latches and product terms?
          Last edited by tms9995; July 4, 2009, 01:40 PM.


            I found reference to an E-Bus controller board someone had for sale a while back for 50 Pounds, so the chip may exist in some form.

            If I have to design it into a larger CPLD, I'll just have to do a socket adapter that carries the correct pins down to the 74LS2001 socket. . .I may have to do that anyway, as VCC and Ground aren't where most chips would put them. . .two signals I have been able to trace to their conclusions.
            Last edited by Ksarul; July 21, 2009, 06:20 PM.
            Enter My Mind At Your Own Risk!


              I added the Aug 1984 ETI article on the Cortex to the repository on WHTech today.
              Enter My Mind At Your Own Risk!


                TMS9995's Cortex emulator is now up on WHtech along with a disk image for CDOS 1.20.
                Enter My Mind At Your Own Risk!


                  I've found some old polaroids of the very 1st Cortex (when it was called Synapse), they are not in brilliant shape but the I've scanned them and put them on flickr at



                    Thanks for those pictures Tony. Looks really weird with a different name on the front panel!

                    1) I see that it still had Powertran on it at that early stage, so I guess it was at the last minute the name was changed?

                    2) Who actually made the original? What I mean is that I expect you had it prototyped and working, but did you then send the design to Powertran and they made the PCB and enclosure?

                    3) Did the original firmware say "Synapse Basic Rev 1.1"?

                    4) Who came up with the font for the lettering and what's it called?


                      Many thanks for the great historical reference pictures, Tony! The Cortex Rules!
                      Enter My Mind At Your Own Risk!


                        > The Cortex rules...

                        No Wiki page - Probably should be...

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


                          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.
                          Enter My Mind At Your Own Risk!


                            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.


                              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


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