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Powertran Cortex

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    I remember the bulletproof ram mod and i also remembered a later mention of it which i eventually found.
    Newsletter 6, page 13 says don't do the mod as it's non reversible, and also, if you fit the memory mapper (which i have) then F000 to FFFF is accessible anyway so it's not needed.
    I will have a test later to see if i can access F000 to FFFF as i've yet to get the external memory card running and this could be related.

    I can write data to the external RAM and read it back out of the RAM (checked with a scope) but the data doesn't make it back to the test program.

    Jim

    Comment


      But surely memory >F000 to >FFFF is only available if you use the memory mapper to map it elsewhere in the processor address space? As the V9938 program is (by the sounds of it) not doing that because it's expecting the Bulletproof RAM mod, it's not actually going to help with that particular problem?

      Stuart.

      Comment


        Yes, you are correct.
        Even with the memory mapper you would have to still swap it out with another block to be able to access it.
        Maybe the bulletproof ram mod is worth doing after all.

        Jim

        Comment


          I've got the MPE expansion ram board from the PP95 running on the Cortex now.
          Once I'd improved my testing program it became more obvious that I had 3 duff ram chips on the board, replacing those (I actually replaced all 16 with NOS ram chips) and the first 4K block tests out ok.
          At the moment I'm just using some modified Basic code from one of the newsletters that copies arrays to and from Extended memory.
          Once I found out that the Cortex uses 6 bytes to store all variables the results made a lot more sense, displaying them as hex helped even more.
          Next to hack the code some more to test the rest of the memory.

          Jim

          Comment


            Originally posted by Ksarul View Post
            Stuart, I'd like one of each of these if they are still available:

            -- 4 off bare MPE FD/WD boards (as used in the PP95 system). Most ICs seem to be address decoding and buffers.

            -- 2 off MPE 9950 CPU-E TMS9995 processor boards. Most chips missing, but one has 2 PALs fitted (address decoding?). I think we have docs for these boards.

            Also, on the MPE Board with the dual 9901s--it is described in one of the Electronics Today articles. It should also have two Joystick ports on it. I could really use a nice picture of the bottom of the board, as I have a layout done that should allow it to be cloned, but I wanted to make sure I didn't miss anything important (the layout for the top side was in the article, and I sussed out the rest but it is always good to have confirmation).

            I may have a 720K half-height as a spare around here too, Stuart.

            Jim
            Hi Jim,
            If you are still working on your copy of the MPE/ETI PIO board then can I suggest some changes around the joystick socket area.
            I've finished off the board I got from Stuart but the 9 way connectors are too close together, the rear of the connectors clashes with other components on the board and you can't bolt them down.
            I had to do some modifications to the connector moulding to get them too fit.

            I will take some pictures if you want.
            Jim

            Comment


              Originally posted by tms9995 View Post

              now i need to figure out a way you can test the cdos 80x26 mode...

              Dave.
              Hi Jim,

              Attached is a text file of a BASIC listing that will put the V9938 (and hopefully the F18A) into 80*26 mode and put a '*' in each corner. I can send you a .cas file if you like so that you don't need to type it in.

              I tried to just paste it here but it kept being converted to lower case, so not sure how to inhibit that...?

              Dave.
              Attached Files

              Comment


                Originally posted by tms9995 View Post

                I can send you a .cas file if you like so that you don't need to type it in.

                Dave.
                Here you go...

                Dave.
                Attached Files

                Comment


                  Hi all
                  My Cortex is still here looking for a good home, I don't think it helps that my posts seem to take up to a week to get past the moderator. By the time my posts get on the site you lot have moved on to the next page.
                  I have no objections to it going to America or even further. I have a business address so it can be collected during the day by a courier.
                  I have also found an a to d board that I don't think is quite finished and a few odd ic's (not 999 series) that can come with it.

                  Norvin

                  Comment


                    Hi Dave,
                    I couldn't get the text2.cas file to work, initialise the cortex and did load "text2" but it just says found ""
                    I downloaded diskimg.cas so i know the setup is ok.

                    Anyway, i renamed the text2.txt file to commands.txt and used the "send command file" option to "type" it onto the cortex.

                    Ran it and it certainly goes into 80 column but not 26 rows, i only got the * in the top corners.
                    A bit of code editing and i think it's only a 24 row mode, changing the y=25 to y=23 on lines 330 and 340 got all 4 *'s

                    Jim

                    Comment


                      Originally posted by Jim Hearne View Post
                      Hi Dave,
                      I couldn't get the text2.cas file to work, initialise the cortex and did load "text2" but it just says found ""
                      I downloaded diskimg.cas so i know the setup is ok.

                      Anyway, i renamed the text2.txt file to commands.txt and used the "send command file" option to "type" it onto the cortex.

                      Ran it and it certainly goes into 80 column but not 26 rows, i only got the * in the top corners.
                      A bit of code editing and i think it's only a 24 row mode, changing the y=25 to y=23 on lines 330 and 340 got all 4 *'s

                      Jim
                      Thanks for trying, Jim. Bummer about that, grrrrrrr.

                      FYI, to load the .cas file just do LOAD"" rather than LOAD"TEXT2" as I didn't give it a name.

                      Dave.

                      Comment


                        Ah, i thought LOAD"" just showed you the name of the file it had found on the tape.

                        I changed line 260 to 260 MEM[D]=MOD[L,10] + ASC["0"] to make it easier to count the rows and columns.

                        I presume it was supposed to do 26 rows ?

                        Jim

                        Comment


                          Originally posted by Jim Hearne View Post
                          Ah, i thought LOAD"" just showed you the name of the file it had found on the tape.

                          I changed line 260 to 260 MEM[D]=MOD[L,10] + ASC["0"] to make it easier to count the rows and columns.

                          I presume it was supposed to do 26 rows ?

                          Jim
                          Fair enough!

                          Yes, line 200 sets the LN bit of R9 in the V9938. This gives it 26.5 lines instead of 24. If I change the 080H to 0H, then I only get 24 lines. Sounds like he didn't implement that feature. No big deal but I would have to change the V9938 CDOS extensions to only use 24 lines if I buy a F18A. Luckily I have the source code!

                          Dave.

                          Comment


                            There isn't a lot of documentation with the F18A but i have a attached a copy of the register list.

                            Jim
                            Attached Files

                            Comment


                              I got the following reply from Matthew the F18A creator.

                              The 26.5 row support of the 9938 is a separate feature not directly
                              related to the 80-column mode, or any other mode. The F18A was designed
                              to be a 9918A replacement so the 9938 feature support is mostly limited
                              to 80-column mode and a few other minor features. However, the F18A does
                              support a 30-row setting that is available in the 80-column mode (and
                              other modes as well), so if you can patch the program you could enable
                              that to get more rows.
                              The 30 row mode sounds interesting, the 80 x 24 mode does give rather tall and thin characters.
                              I'm not sure if that's something the V9938 does or only the F18A, I've asked for more details.

                              Jim

                              Comment


                                Originally posted by Jim Hearne View Post
                                I got the following reply from Matthew the F18A creator.



                                The 30 row mode sounds interesting, the 80 x 24 mode does give rather tall and thin characters.
                                I'm not sure if that's something the V9938 does or only the F18A, I've asked for more details.

                                Jim
                                That's very interesting. Maybe when you get the relevant register info, you can try patching the BASIC prog to see if it works?

                                If it does work OK, I might buy one and have a go at patching V9938 to drive it. Be nice to have the option of using an LCD monitor on the Cortex without the use of some sort of converter etc.

                                Thanks for the info,

                                Dave.

                                Comment

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