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Powertran Cortex

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    I have had an offer from Stuart for the disc controller chip, but I don't want to break the cortex and I don't want money for it. I just want it to go to a good home
    I don't have any documentation that is no already mentioned on the forum, I do have the cortex manual and the mdex manual plus the original construction notes.
    all the above will come with the machine.

    Norvin

    Comment


      CIMG1728.jpgCIMG1730.jpg
      Some pictures

      Norvin

      Comment


        I agree with Stuart, looks great!

        Regarding the F18A, have you tried the 80 column mode with CDOS and MDEX? I'd like to be sure they work before plonking down my credit card.

        Thanks,

        Dave.

        Comment


          Thanks

          I don't think i any disk images with 80 column mode on and recompiling MDEX as per newsletter 21 is probably a bit beyond me at the moment.

          If you can send me a disk image i'll certainly try it for you.

          Jim





          Originally posted by tms9995 View Post
          I agree with Stuart, looks great!

          Regarding the F18A, have you tried the 80 column mode with CDOS and MDEX? I'd like to be sure they work before plonking down my credit card.

          Thanks,

          Dave.

          Comment


            Originally posted by Jim Hearne View Post
            Thanks

            I don't think i any disk images with 80 column mode on and recompiling MDEX as per newsletter 21 is probably a bit beyond me at the moment.

            If you can send me a disk image i'll certainly try it for you.

            Jim
            Thanks Jim,

            There is a ZIP on my website that contains the complete suite of CDOS & MDEX disks. Where appropriate, I pre-configured them for both 40 or 80 column modes. Disks titled CDOS40... or MDEX40... will boot to 40 column mode whereas the ones titled CDOS80... or MDEX80... boot into 80 column mode.

            Here's the link:

            http://www.powertrancortex.com/downl...ex%20Disks.zip

            Dave.

            Comment


              I hate to admit to this but I always assumed that the 40 and 80 on those file names referred to them being on 40 or 80 track disks.............

              Oops.

              Jim

              Originally posted by tms9995 View Post
              Thanks Jim,

              There is a ZIP on my website that contains the complete suite of CDOS & MDEX disks. Where appropriate, I pre-configured them for both 40 or 80 column modes. Disks titled CDOS40... or MDEX40... will boot to 40 column mode whereas the ones titled CDOS80... or MDEX80... boot into 80 column mode.

              Here's the link:

              http://www.powertrancortex.com/downl...ex%20Disks.zip

              Dave.

              Comment


                Originally posted by Jim Hearne View Post
                I hate to admit to this but I always assumed that the 40 and 80 on those file names referred to them being on 40 or 80 track disks.............

                Oops.

                Jim
                Well it does mention it in the README but I have to confess that's not the easiest thing to read...

                Dave.

                Comment


                  In which case i have to confess to having not read or not noticed the README file before......

                  Jim

                  Originally posted by tms9995 View Post
                  Well it does mention it in the README but I have to confess that's not the easiest thing to read...

                  Dave.

                  Comment


                    Originally posted by Jim Hearne View Post
                    In which case i have to confess to having not read or not noticed the README file before......

                    Jim
                    The trouble when you (well me anyway!) tries to put all this together from scratch, it seems so clear at the time. I'm sure approaching it from the 'outside', it's clear as mud

                    Dave.

                    Comment


                      Hi Dave, I just created the CDOS80 Release dsk from the image.
                      But when i boot from it it stops with "** illegal opcode ** at 1150

                      This seems to be the line load 0,"V9938"
                      Any thoughts ?

                      Many thanks,

                      Jim

                      Comment


                        Originally posted by Jim Hearne View Post
                        Hi Dave, I just created the CDOS80 Release dsk from the image.
                        But when i boot from it it stops with "** illegal opcode ** at 1150

                        This seems to be the line load 0,"V9938"
                        Any thoughts ?

                        Many thanks,

                        Jim
                        Hi Jim,

                        I think the problem is because the V9938 enhancements are loaded at >F200. In order to do this, the Cortex needs modifying to free up the RAM that's normally decoded as Memory Mapped I/O. By default it decodes >F000 to >FFF9 as I/O but there are a whole bunch of unused chip-selects in the range >F160->F1E0 which normally suffice for user-expansion. So, a mod was developed to use the spare RAM from >F200 to >FFF9. In addition, the circuitry also allowed the DMA to directly load into this range. Can't remember if it was done in one or two mods, but think it's all described in the News Letters.

                        OK, without that, can you try (using the *MDEX loader on your normal 40 column CDOS) to load the MDEX80 System Release.dsk image? The MDEX driver just uses the normal RAM region.

                        Thanks,

                        Dave.

                        Comment


                          Hi Dave,

                          MDEX80 seems to work fine in 80 column mode on the F18A

                          Jim


                          Originally posted by tms9995 View Post
                          Hi Jim,

                          I think the problem is because the V9938 enhancements are loaded at >F200. In order to do this, the Cortex needs modifying to free up the RAM that's normally decoded as Memory Mapped I/O. By default it decodes >F000 to >FFF9 as I/O but there are a whole bunch of unused chip-selects in the range >F160->F1E0 which normally suffice for user-expansion. So, a mod was developed to use the spare RAM from >F200 to >FFF9. In addition, the circuitry also allowed the DMA to directly load into this range. Can't remember if it was done in one or two mods, but think it's all described in the News Letters.

                          OK, without that, can you try (using the *MDEX loader on your normal 40 column CDOS) to load the MDEX80 System Release.dsk image? The MDEX driver just uses the normal RAM region.

                          Thanks,

                          Dave.

                          Comment


                            Originally posted by Jim Hearne View Post
                            Hi Dave,

                            MDEX80 seems to work fine in 80 column mode on the F18A

                            Jim
                            Thanks Jim, much appreciated.

                            Now I need to figure out a way you can test the CDOS 80x26 mode...

                            Dave.

                            Comment


                              Originally posted by tms9995 View Post
                              Thanks Jim, much appreciated.

                              Now I need to figure out a way you can test the CDOS 80x26 mode...

                              Dave.
                              Hi Dave,
                              Unless i'm missing something I can't find anything in the newletters about having to mod the Cortex main board to use the Maplin V9938 board.
                              I've found the articles about connecting it to the E-bus, and via a 40 pin header fitted instead of the VDP, but the only mention is of a need to pick up A14 from the FDC.

                              Many thanks,

                              Jim

                              Comment


                                Originally posted by Jim Hearne View Post
                                Hi Dave,
                                Unless i'm missing something I can't find anything in the newletters about having to mod the Cortex main board to use the Maplin V9938 board.
                                I've found the articles about connecting it to the E-bus, and via a 40 pin header fitted instead of the VDP, but the only mention is of a need to pick up A14 from the FDC.

                                Many thanks,

                                Jim
                                Hi Jim,

                                As far as the hardware goes in relation to the Maplin V9938 card, you are correct that it was basically a direct replacement (with the exception of needing A14) and, as such, no further hardware/software mods are required.

                                Chris Young came up with a bunch of extensions to Cortex Basic to make use of the additional Text and Graphics modes. To avoid further reducing the free RAM, he decided to use the 'invisible' upper RAM from >F200 to >FFF9. However, this RAM isn't available unless the 'Bulletproof RAM' mod on Page 3 of News Letter 1 has been performed.

                                Unfortunately, since your freshly made Cortex doesn't have this mod, this is why you get the Illegal Opcode when CDOS tries to load and run the V9938 program.

                                I can't remember if there is an additional mod required to get the DMA to load directly to addresses of >F000 and above.

                                Dave.

                                Comment

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