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Thread: Color Computer EPROM problem

  1. #1
    Join Date
    May 2006
    Location
    Hamilton, Ontario, Canada
    Posts
    3,780

    Default Color Computer EPROM problem

    Hi,

    I'm having a problem with burning a diagnostic EPROM (2.0) from a .ccc that perhaps someone could help me with.
    I have the file and I converted it to a .bin file using Joe Strosnider's CCC-TO-BIN program.
    When I load it into the TL-866CS buffer, it looks good and I can see the ASCII parts of the menu and it burns to a 2732A EPROM without any apparent problem.
    I put it into a cartridge containing one of NF6X's CoCoEPROMPak boards, in the 24 pin socket section, put on the auto-start jumper and plug it into a Color Computer.
    What I get is a green screen with black lettering on the first line as below;

    R Diagnostics ROR (with the word centered in the top line, the single R on the left of the line and the ROR about 6 spaces to the right of the word).

    That's it.
    I'm guessing that it's, possibly, trying to make me aware of an error.
    I have tried several ROMs in a color basic CoCo 1 and two Extended color basic CoCo 2s (I haven't tried in in a CoCo 3 because I don't even know if it would work in it).
    Can anyone spot what I might be doing wrong or offer some guidance?

    TIA
    Legacy Computers and Parts

    Sales of, parts for, and repairs to, Vintage and Legacy computers.

  2. #2
    Join Date
    May 2006
    Location
    Hamilton, Ontario, Canada
    Posts
    3,780

    Default

    I forgot to mention that the program is only 2K in length.
    Would I have to join two copies together and burn it or set start and end addresses?
    Legacy Computers and Parts

    Sales of, parts for, and repairs to, Vintage and Legacy computers.

  3. #3

    Default

    I suspect it is because you are using the wrong part. Looking at the schematic, you are suppose to use a 24 pin 8Kx8 part. Without an adapter you are not even matching the address pins. Also, if this is to be a boot, I believe it needs to load in the high part of the EPROM, not at address 0.
    Ops, I see you have some type of adapter.
    I guess the question is what address do you expect it to run at?
    Dwight

  4. #4

    Default

    My guess is that you have to put the code at the higher half of the EPROM.
    Dwight

  5. #5
    Join Date
    May 2006
    Location
    Hamilton, Ontario, Canada
    Posts
    3,780

    Default

    Thank you Dwight.
    Yes, I am using a board designed by NF6X on the forums here for use with more current EPROMs in the Color Computer.
    I will have to read up on where the computer expects the cartridge ROM to be located.
    This is not really my forte, so I'll have to figure it out.
    Legacy Computers and Parts

    Sales of, parts for, and repairs to, Vintage and Legacy computers.

  6. #6
    Join Date
    May 2006
    Location
    Hamilton, Ontario, Canada
    Posts
    3,780

    Default

    Thanks to NF6X, we were able to figure out the problem and the cartridge works.
    On the down-side, it will only test 16K of memory...Sigh.
    Legacy Computers and Parts

    Sales of, parts for, and repairs to, Vintage and Legacy computers.

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