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Debugging a KIM-1 computer

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    Thanks for the pointer.

    I was looking on the adapter and the data sheet for the EEPROM.
    I have G* and E* swapped. I'll fix that before running my code to program
    the -002 data.
    I'll post a new schematic soon. I want to make sure there are no other issues.


      I'm having problems programming the EEPROM. I've read the spec
      several times and think I got it right.
      I'd got the EEPROM from Anchor Electronics and I suspect it has the
      software protect enabled. I may have miswired something as well.
      I'd not setup the addressing to be able to undo the software disable
      so I had to rip it out to rewire. I had it nicely tucked under the sockets
      but now it'll dangle off to the side because I'm not digging in there again.
      Anyway I'll want it off to the side where I can put an oscilloscope on
      I'd just put pullups on the unused addresses. I'm going to need to attach
      the odd and even address, A10, A11 and A12, to odd and even addresses
      that are being use. In other words, connect A12 to A8, A11 to A9 and A10
      to A6 as pairs. That way I can do 1555 and 0AAA addresses needed.
      I suspect that Anchor got some NOS that had been preprogrammed and software
      locked. I can use the software lock rather than a jumper on the WE\ pin.
      I only need the jumper for -002 and -003, making things simpler.
      Last edited by Dwight Elvey; November 25, 2016, 09:05 AM.


        Originally posted by Dwight Elvey View Post
        I'd got the EEPROM from Anchor Electronics and I suspect it has the
        software protect enabled.
        What brand of 28C64? SEEQ, Xicor, NEC, ? They should be erasable in your PROM Programmer no matter any software protect. I think the most Programmers erase the part before programming new data.

        Most 28C64's allow +12V on the OE signal (pin 22) with CE and WE low for 10mS to erase the chip.


          It is a ST M28C64A. The data sheet seem to indicate that
          the A type doesn't support the bulk erase.
          I'd swapped the WR* and G* wires so it wasn't right.
          I've swapped the wires but still have no luck. I've not yet
          tried the soft protect disable.
          I'll do that this morning.


            Between bungling the code, the programmer and the swapped
            wire, I'd had a lot of mistakes.
            I've booted the KIM to the EEPROM. Yaaaaeeee!
            Now to learn to do the KIM input.
            Also write some more test code.
            Part of the problem was that after fixing the swapped wire,
            I'd been using the EPROM programmer wrong. It has a separate
            step to enter the file name and then transfer the file to
            its buffer. I'd been to frazzled that I realized that I didn't
            remember to transfer the file to the buffer ( separate step ).
            There was so many steps and I was just wearing down.
            I have the LED doing two things. If the code is loading, it
            flashes fast and then goes out if it worked.
            If it failed it would come on steady. I've been seeing the
            steady light so much I'd just about given up.

            Early on, I realized that once I switched the ROM to be the -002
            image, I'd lose the NMI vector in my boot image. The KIM expects
            it to vector through the RAM at $17FA. I've not written the test
            code yet to check the RAM in the -002 or the -003 so I'd modified
            my -002 image to go to my EEPROM programming code in RAM.
            I need to test that RAM to make sure it will take the
            jump to interrupt vector. Then I can have a clean image.
            I'd done that to minimize the variables.
            I'll write code to patch the correct vector in the EEPROM as
            part of the programming code.
            It is all complicated.


              Originally posted by Dwight Elvey View Post
              It is all complicated.
              Still a great read! Any progress to report?



                Sorry for the long delay on getting back on progress.
                I've made a prototype run of boards. I've not checked the adapter boards
                yet because I'm waiting on a friend that is blowing the PAL fuses for
                The debug has a couple non-functional issues but otherwise works.
                I did forgot the pullup resistors on the K3, K4 and DEN lines. I'll fix this on then
                main run of boards. For now, I'll tack on resistors.
                I'd not made the solder mask clearance on the bottom of the board
                for the connectors ( required some scrapping ).
                The adapter boards ( 2 are stacked ) had the holes for the interconnect
                too small. I'd planned on using 28 ga. wire but the holes only fit 30 ga.
                I'm glad I'd made a proto run.
                Considering that this is my first boards I'm reasonably happy.
                I've got a connector issue. The 44 pin connectors I located don't have
                enough end clearance, for more blank board at the ends of the pins. I'm thinking
                I may just use a small end mill the extend the ends.


                  One shows the two small adapter boards that would go under the
                  6532, to replace the 6530.
                  The other shows the debug board attached to the extension connector.
                  Notice the rats nest in place of the 6530-002. To the right of the 6532 is
                  the EEPROM holding the -002 code. The other dark blob is the two logic
                  chips that form the address decoding.
                  The first two small boards replace these.
                  I'll have an update this weekend with the small boards put together
                  and hopefully working.
                  Attached Files


                    I finally got around to debugging my adapter. It is often hard to debug ones own work. Especially when you get older. I had everything working except for the phase of clk2. Luckily it is a PAL change so it is a simple source change. I chose the wrong phase for what the board had.
                    I was going to post a picture but I can't figure how to do that on this new MB. I can't even see my older pictures?
                    I'll make a run of the corrected boards.
                    The adapter had 2 issues. The board interconnect holes were two small ( I had to use 30 ga. wire instead of the planned 28 ga. ). I also missed one wire.
                    The debug board missed a three pullup resistors but otherwise worked fine.
                    My progress has been slow but I'm finally seeing the end.
                    I've written most all of the debug code for the debug board. I need to write up the instructions as well.
                    Progress is being made.


                    You can see the wire to U16 for the proper clock. It will be fixed in the next PAL.
                    Last edited by Dwight Elvey; April 23, 2017, 10:35 AM.


                      Dwight that's some nice looking stuff - you are an artist.
                      Surely not everyone was Kung-Fu fighting