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Re: [midatlanticretro] Re: IMSAI 8080

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  • Systems Glitch
    ... Some of the older hardware was designed to take advantage of some very specific aspects of the 8080 s timing. I discovered this with my Solid State Music
    Message 1 of 61 , Jan 31, 2013
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      > And then there's the problem of running some software designed for the 8080A (4K BASIC is the common example). The Z80A is not a perfect replacement for the 8080A. The Dutronics board (with all it's extra logic chips) does a good job at coming *close* to mimic the 8080A.

      Some of the older hardware was designed to take advantage of some very specific aspects of the 8080's timing. I discovered this with my Solid State Music PB-1, which uses extremely long wait states to burn EPROMs mapped in as RAM. It sort-of worked some of the time with my Cromemco ZPU (only at 2 MHz), and refused to burn more than a byte or two with my IMS Z80 board at any speed.

      It's an usual use of wait states, but I couldn't make full use of my PB-1 until I picked up a true 8080 based CPU board.

      Thanks,
      Jonathan
    • DanielB
      Yep, front panel is working good now. One odd thing I have run into is that from the Zapple monitor I can write to the SMB s onboard RAM, but I cannot write to
      Message 61 of 61 , May 14 1:24 PM
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        Yep, front panel is working good now. One odd thing I have run into is that from the Zapple monitor I can write to the SMB's onboard RAM, but I cannot write to the RAM on the memory board but I can write to the memory board from the front panel.

        Dan

        --- In midatlanticretro@yahoogroups.com, joshbensadon <no_reply@...> wrote:
        >
        >
        >
        > --- In midatlanticretro@yahoogroups.com, "DanielB" <danlb_2000@> wrote:
        > >
        > > After bad chips I finally got the front panel working, and after a couple bad tantalum caps on the SMB I also got that working. Very exciting when I got the Zapple monitor prompt!
        > >
        > > https://lh6.googleusercontent.com/-uQShOzInDeE/UZFoWnYYpsI/AAAAAAAACII/80vupyb6Psc/w883-h662-no/IMG_3933.JPG
        > >
        >
        >
        > Daniel,
        >
        > That's looking great! Very well done :)
        >
        > Can you now Examine/Deposit via the front panel?
        >
        > :)J
        >
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