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Thread: Z80 Type-In Program Listing

  1. #31


    Hi Mike,
    Thanks again for your help. The card lives! I have managed to get it booting and talking over RS232.
    A couple of things:

    The board is marked SBC-780 (Rev-A) but the MON code for the 880 so far works.

    I replaced the MC1488/MC1489 Serial Driver/Receiver chips with a MAX232. This means I can run the board on +5v only..
    I suspect I have a problem with the driver circuit from terminal. Hoping someone can help me diagnose... It could also be terminal settings..?

    When I enter a character via terminal it seems to automatically assume enter has also been pressed. I can't enter string of commands at the terminal as it appears in the manual.

    Is this a terminal setting problem?

  2. #32


    OK So I am wondering how best to troubleshoot this ?
    If I capture the RS232 traffic coming from the device and compare to the packets being sent to the device, maybe a difference will be apparent..?

    Another thing I dont understand, the baud rate is set to 9600 in the ASM code. I can connect at 9600 but get XXXXXX as the output on screen for every keypress. If i connect from PC using 2400 baud I get the display banner and keypresses translate to the correct key, just everything goes on a new line....

  3. #33


    The monitor code is looking for upper case letters...


  4. #34


    I didn't even consider that... Well there you go..
    It works perfect when you enter a capital.

    Thanks again Mike...

  5. #35


    Gotta love old computers and software


  6. #36


    Hi Guys,

    Any idea's if enabling phantom mode on this card would disable I/O for serial console?
    I'm at the point I have enabled phantom mode, I can see the card is still booting from the onboard EEPROM but the console is failing to work.
    The MON code appears to get stuck in a loop now trying to send data over the serial port...

    Should I expect the onboard I/O addressing to work in phantom mode for RS232 communication?

  7. #37


    The EPROM is enabled after power on or reset. It remains enabled until a memory read is done at the address specified on SW3. Once the address on SW3 is accessed (bits A11-A15), then the on board EPROM is disabled and the monitor isn't present anymore. This is most likely what's happening to you rather than serial I/O being disabled.



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