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Powertran Cortex

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    Sorry, for some reason I thought the card would have only 64Kb ram.

    Comment


      Just emailed Funkward-tech they can do the ICs for $25 all in (with shipping etc)

      U1 TMS9995
      U2 74LS612
      U3 74LS14
      U4 AT28C256
      U5 628512-55
      U6 74HCT688
      U8 TMS9902A
      U10 74LS259
      U11 GAL22V10D
      U12 74LS74
      U13 74LS112
      U14 74LS138

      ** Not 512K SRAMs are normally 55ns Speed
      AT28C256 are 120ns,150ns,200ns !!
      Maybe using a W27C512-45 (45ns) 64K EEPROM may be better than the 32K AT28C256 ??


      ********

      kit $25


      B/Rgds,
      Paul


      Funkward Technology Co.,Ltd
      Room 903,B Bldg,Ze Run Hua Ting,Baoli Road,
      Buji Town,Longgang District,
      ShenZhen, 518112,China
      Tel:0086-755-83212558
      Fax:0086-755-83212558
      Email: info@funkward.com
      Facebook: Paul Huye
      Twitter: paulwooyee
      Skype: paulwooyee


      If enough people ask he may pop it onto his website (ebay Shop) !

      Price is for one Kit.. you could get a discount if buying more than one !

      Hope this is useful ?


      *** Best to specifiy EXACT part numbers including speed rating for this like RAM,ROM, GALs etc otherwise you may get something which is too slow !

      Comment


        The most cost effective option would be :

        128K x 8 Bit SRAM DIP32 (55ns) TC551001-5,KM681000-55 etc <$1.0 each
        DS1250 512Kx8bit NVSRAM (70ns) DIP32 about $2.50 each
        W27C512-45 64Kx8bit EEPROM (45ns) DIP28 <$0.80 each

        Whereas a 512K SRAM 55ns are usually $3.50 each wholesale and the AT28C256 are rather slow >100ns or so !

        Originally posted by mnbvcxz View Post
        Since a 512K x 8 static ram chip is not much more expensive than a 64K x 8 chip, would you make the PCB able to take either chip, perhaps 2 chips giving either 128KB or 1MB maximum.
        Even the Sinclair Spectrum had 128KB ram, and the Cortex was designed to be expandable to 1MB.

        Comment


          U7 Sparkfun slim CF Card Board

          I don't think Sparkfun still stock this ??

          Possible alternatives on ebay.com ???

          http://www.ebay.com/itm/CF-Compact-F...item27dd858a58

          http://www.ebay.com/itm/Compact-Flas...item58ba9e63c5


          These are <$1.50 each but will they do the same Job ??

          Comment


            Originally posted by lezanderson View Post
            I don't think Sparkfun still stock this ??
            Correct, it is out of production. However, there is still some stock floating around in the retail channel.

            The boards you link to are 'IDE mode' boards, the Sparkfun board is 'memory mode'. The two modes are similar but not identical, unfortunately. I have not found another memory mode board.

            For the handful of people building the Mini Cortex the remaining stock is probably sufficient. In the unlikely event that there are suddenly tens of people building this, the best solution imho would be to have the CF Card socket directly on the main PCB and to find a PCB manufacturer that is willing to solder on the CF Card socket for a modest fee.

            Paul

            Comment


              Mini Cortex EPROM AT28C256 ??

              With reference to the Mini Cortex....any reason for using the rather slow 28C256 as these are normally 100,120,150ns or so whereas the W27C512-45 is 45ns and the same price (if not cheaper) ! The AT28C256 must clearly need wait states slowing down the system ?

              Comment


                Originally posted by lezanderson View Post
                Just emailed Funkward-tech they can do the ICs for $25 all in (with shipping etc). (...) If enough people ask he may pop it onto his website (ebay Shop) !
                That is very convenient. I hope that answers the question of "ti99/4a" about costing, thank you for looking into this.

                Originally posted by lezanderson View Post
                With reference to the Mini Cortex....any reason for using the rather slow 28C256 as these are normally 100,120,150ns or so whereas the W27C512-45 is 45ns and the same price (if not cheaper) ! The AT28C256 must clearly need wait states slowing down the system ?
                With no wait states, access time for the EPROM must be 120ns or better (TMS9995 timing requires 115ns). The memory mapper takes 40ns, so the RAM must be 70ns or better. The previous breadboard circuit runs without wait states and after a lot of fiddling is running stable. I've added the wait state circuit so that it can run stable without fiddling (and so that I can try a 4Mhz 9995 if I want to -- hence the 55ns RAM). With the wait state (for ROM and I/O access only!) access time can be as slow 450ns.

                As for system speed, it is only important that the RAM is fast: the ROM is only used at boot time, afterwards everything runs from RAM.

                Why the 28C256? Main reason is that I had those in my parts drawer, any other pin compatible 32Kx8 (E)EPROM will do. A pin compatible 64Kx8 part is possible too, but only the bottom 32K would be used. I've thought about an in-circuit ROM update facility with the 28C256, but that is not in the current design.

                Comment


                  Using CPLDs instead of Old Slow 74LS ICs ??

                  As old 74LS TTL ICs now start to look like dinosaurs , things like 74LS612 (40ns !!) perhaps we should consider using more modern CPLDs to do the job ? CPLDs like the Altera MAX 7000 series, namely EPM7128SLC84,EPM7064SLC44 typesd which are cheap and fast.. The EPM7128SLC are normally 10ns or 15ns the EPM7064SLC can be as fast as 5ns !

                  And as these are cheap ... the EPM7128SLC are $2.0 each, programming them to be a Memory Mappers, CRU decoders etc may be the future ? Especially if using CPUs like the TMS99105/TMS99110 !

                  Comment


                    Originally posted by lezanderson View Post
                    Using CPLDs instead of Old Slow 74LS ICs ??

                    As old 74LS TTL ICs now start to look like dinosaurs , things like 74LS612 (40ns !!) perhaps we should consider using more modern CPLDs to do the job ? CPLDs like the Altera MAX 7000 series, namely EPM7128SLC84,EPM7064SLC44 typesd which are cheap and fast.. The EPM7128SLC are normally 10ns or 15ns the EPM7064SLC can be as fast as 5ns !

                    And as these are cheap ... the EPM7128SLC are $2.0 each, programming them to be a Memory Mappers, CRU decoders etc may be the future ? Especially if using CPUs like the TMS99105/TMS99110 !
                    If you enjoy playing/designing/tinkering with the hardware, then reducing everything down to just one or two big, fast chips is often not the object of the exercise. Personally, I like a board to look as if its actually doing something, and a board containing just one great big CPLD holds no interest whatsoever. Might as well just run it in emulation on a laptop and not bother with the hardware at all.

                    Just my $0.02.

                    Stuart.

                    Comment


                      Originally posted by Stuart View Post
                      If you enjoy playing/designing/tinkering with the hardware, then reducing everything down to just one or two big, fast chips is often not the object of the exercise. Personally, I like a board to look as if its actually doing something, and a board containing just one great big CPLD holds no interest whatsoever. Might as well just run it in emulation on a laptop and not bother with the hardware at all.

                      Just my $0.02.

                      Stuart.
                      The point of CPLDs is to reduce costs and board size by putting a lot of very small and fiddly TTL ICs onto one chip... in the same way a CPU is all on one chip. The Cost and Speed advantages of using things like GALs and CPLDs can be great.

                      CPLDs are one of those things you either hate them or love them...but either way they are a VERY useful tool to both the professional and hobby designer ! And learning new electronics skills must be good ?

                      Comment


                        Originally posted by lezanderson View Post
                        The point of CPLDs is to reduce costs and board size by putting a lot of very small and fiddly TTL ICs onto one chip... in the same way a CPU is all on one chip. The Cost and Speed advantages of using things like GALs and CPLDs can be great.

                        CPLDs are one of those things you either hate them or love them...but either way they are a VERY useful tool to both the professional and hobby designer ! And learning new electronics skills must be good ?
                        I guess its horses for courses. Back when I was about 20 I wanted to run Unix on a heavily modified 99/4A (the result being quite like a Cortex). Although I got some of the building blocks together I never finished it and it has itched me ever since. The Mini Cortex is optimised to scratch that itch. Cost and speed are minor considerations.

                        Perhaps the Geneve 2 is a project for you (http://atariage.com/forums/topic/235801-geneve-2/)?

                        Comment


                          Originally posted by Stuart View Post
                          Hi Ermanno. You want to be able to list a BASIC program to a text file on the PC? It's possible using the serial terminal feature of the emulator, but takes a couple of steps:

                          (1) Load the program into the emulator.
                          (2) In the emulator, select Terminal > Serial Terminal from the menu. This should display a second window.
                          (3) Select Terminal > Start Terminal Log from the menu. This will display a Windows file dialog where you specify the file to list the program to. By default the file will have a .trm extension, but it's just a plain text file.
                          (4) At the Cortex prompt in BASIC, type UNIT 2<Return>. Everything that appears on the screen will now also be sent to the serial terminal window. And everything sent to the serial terminal window will be captured in the log file.
                          (5) At the Cortex prompt in BASIC, type LIST<Return>. You should be able to work out what's going to happen.
                          (6) Select Terminal > Stop Terminal Log from the menu. The plain text log file now contains the program listing.
                          (7) Typing UNIT -2<Return> at the BASIC prompt will stop output going to the serial terminal window.

                          I'm expecting someone to point out a far easier way to do it that I've missed!

                          Stuart.
                          See msg #684 on page 69, it details 'raw save' mode. ie.use F7 (supply name file), UNIT 3, LIST, then menu option 'stop raw record'

                          I used it recreate the source code for CDOS (both TMS9909 and TMS2797). Can post it here if that's OK...

                          Regards

                          Comment


                            Originally posted by daveSCMP View Post
                            I used it recreate the source code for CDOS (both TMS9909 and TMS2797). Can post it here if that's OK...
                            That is wonderful news! I had contemplated making CDOS work with the CF Card on the Mini Cortex, but never found the time or motivation to recreate its source code.

                            Comment


                              Powertran Cortex ICs

                              I've being trying to source ICs for the original Powertran Cortex. A BOM (Bill of materials) ICs is below with approx prices from Funkward-Tech. Note : Some ICs can be sourced cheaper on ebay.com. I've seen the TMS9995 for $6.99 ?? but it does give an idea of costings if your wanting to build a Cortex from a bare PCB.

                              Obviously what Funkward-tech can't source can be obtained from other suppliers, possibly cheaper anyhow !


                              TMS9995 1pcs $8.5/EA
                              TMS9902 2pcs $1.5/EA
                              TMS9911 1pcs $6.0/EA
                              TMS9909 1pcs NO SOURCE
                              TMS9929 1pcs NO SOURCE
                              TMS2564 3pcs NO SOURCE
                              TMS4500 1pcs $2.0/EA
                              TMS4164 8pcs NO SOURCE
                              TMS4116 8pcs $1.0/EA
                              74LS04 5pcs $0.5/EA
                              74LS74 7pcs $0.5/EA
                              74LS86 1pcs $1.0/EA
                              74LS00 4pcs $0.5/EA
                              74LS02 3pcs $0.5/EA
                              74LS10 2pcs $1.0/EA
                              74LS244 8pcs $0.5/EA
                              74LS08 3pcs $0.5/EA
                              74LS139 3pcs $0.5/EA
                              74LS07 5pcs $0.8/EA
                              74LS164 1pcs $1.0/EA
                              74LS20 1pcs $1.0/EA
                              74LS32 4pcs $0.5/EA
                              74LS612 1pcs $2.0/EA
                              74LS27 2pcs $0.85/EA
                              74LS139 2pcs $0.5/EA
                              74LS245 2pcs $1.0/EA
                              74LS251 2pcs $1.0/EA
                              74LS259 1pcs $1.0/EA
                              74LS123 1pcs $0.5/EA
                              75189A 1pcs $1.0/EA
                              74LS73 1pcs $0.85/EA
                              75188 1pcs $1.0/EA
                              74LS297 1pcs $2.0/EA
                              74LS2001 1pcs $2.0/EA
                              4046B 2pcs $1.0/EA
                              4013 1pcs $1.0/EA
                              LM1889 1pcs $2.0/EA
                              LM339 2pcs $1.0/EA
                              TL08 1pcs $1.0/EA

                              Comment


                                Originally posted by pnr View Post
                                That is wonderful news! I had contemplated making CDOS work with the CF Card on the Mini Cortex, but never found the time or motivation to recreate its source code.
                                The source is uncommented as yet, I did it as I was curious how CDOS was loaded and linked into Cortex OS. There are 3 files for each version of FDC. The boot sector gets loaded to >6100, which then loads file SYSTEM$ above it at >6900. Links are then made into CDOS. The FORMAT code is loaded and called as required.

                                I don't have any Cortex hardware, just used the excellent emulator. Though there is one small point to note. the emulator disks for TMS9909 all have their boot sector 16 word header block skewed by one byte (TMS2797 are correct).
                                Attached Files

                                Comment

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