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Thread: Tei computer

  1. #11

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    So I've put in an EPROM C3 E8 00. Lets see. Nope.. Nothing...
    And then I thought, hey there was something about that address. Low Byte first then the High Byte.

    So tried again. Now with: C3 00 E8 in the EPROM. And yes! The FDC starts to read!
    The dip switches on F0xx seem to be the start address of that EPROM.

    So you can use this board without EPROM and just put in a jump address to a FDC controller or whatever.
    Or you can put in a monitor program or whatever in that EPROM and just set F0xx in the dip switches....


    Quote Originally Posted by glitch View Post
    CP/M will run on an 8085, but if you have a version that does use Z80 opcodes, yes, it will crash! North Star DOS will also work with an 8080/8085 unless it has been customized for a system with a Z80.
    Well, I've no idea if and how the CP/M for the Northstar is optimised for the Z80. My first guess is that it is optimized
    because the Northstar primary is a Z80 machine. (As far as I know never sold with a 8080, please correct me if I'm wrong.)

    I don't know if I have NS-Dos. Have to look...

    Quote Originally Posted by glitch View Post
    The EPROM may be a ROM monitor, to allow doing system maintenance without having to boot a diskette. Many ROM monitors are like this, and also support jumping to a floppy boot routine (looks like yours does that, since you found a string asking which floppy to boot from).
    Yes you are right. After turning on this machine if should display that message before booting at all.
    The little problem here: Nothing shows up on the serial port. Maybe this has something to do with
    the missing floppy controller.

    At lease I know now how to use the CPU board.

    The serial card can be a problem as well... Maybe I can run the eprom code in an emulator to see
    which addresses are used to output the text messages... This should tell a bit more about the serial card.

    The 64K memory card is probably set with a little memory hole for the fdc etc...

    I could just put in a new known board set in the Tei machine. Then it will run in no time.
    But I prefer to figure out these original cards... Otherwise it isn't a Tei machine any more...

    It seems your Tei CPU board has an empty socket too. Would that be a front panel connector?
    http://www.glitchwrks.com/2016/05/31/tei-8080-cpu

    Regards, Roland
    Last edited by Roland Huisman; June 18th, 2017 at 04:35 AM.
    WTB: Case for Altair 8800 ...... Rolands Github projects

  2. #12
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    Yes, that's an IMSAI-style front panel connector in the top right corner.

    You can get CP/M for the North Star controller without Z80 code as North Star originally sold their single-density controllers as a separate product for S-100 system owners. I currently use a North Star single-density controller with my IMSAI, with an 8080 CPU board. I believe Mike Douglas or Martin Eberhard has ported CP/M 2.2 to the North Star single density controller as well, so there's that if the North Star double density CP/M does in fact include Z80 opcodes.

    CP/M may also be getting stuck at the console I/O initialization or one of the character output routines -- if your serial console port isn't at the address that it's expecting, it could be sitting there waiting for a flag bit to flip in the status register, which will never happen if the UART is at the wrong address. It does look like your serial I/O board uses Intel 8251A UARTs, like the North Star, so it's probably possible to address it appropriately for unmodified North Star CP/M and North Star DOS. You can probably disassemble the ROM monitor and figure out which I/O ports it's using.

    Of course, if the monitor ROM isn't signing on, and you haven't changed any switch settings on the serial I/O board, there may be something wrong with the I/O board, or your serial cables, et c. I'd attach a serial light box to the port and figure out if it's something as simple as needing a null modem cable, first!

  3. #13

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    Quote Originally Posted by glitch View Post
    Yes, that's an IMSAI-style front panel connector in the top right corner.
    Great. Does the connector have the same pinout as well?

    Quote Originally Posted by glitch View Post
    You can get CP/M for the North Star controller without Z80 code as North Star originally sold their single-density controllers as a separate product for S-100 system owners. I currently use a North Star single-density controller with my IMSAI, with an 8080 CPU board. I believe Mike Douglas or Martin Eberhard has ported CP/M 2.2 to the North Star single density controller as well, so there's that if the North Star double density CP/M does in fact include Z80 opcodes.
    Interesting! The only software I have is that what came with the machine.
    I've got several versions for different memory sizes. But they all boot up like:

    32K CP/M vers 2.2 Horizon rev 1.2.0 QD
    Product of North Star Computers,Inc.

    Quote Originally Posted by glitch View Post
    CP/M may also be getting stuck at the console I/O initialization or one of the character output routines -- if your serial console port isn't at the address that it's expecting, it could be sitting there waiting for a flag bit to flip in the status register, which will never happen if the UART is at the wrong address. It does look like your serial I/O board uses Intel 8251A UARTs, like the North Star, so it's probably possible to address it appropriately for unmodified North Star CP/M and North Star DOS. You can probably disassemble the ROM monitor and figure out which I/O ports it's using.
    Hmm maybe my story was not clear... Until now I've only put in the Tei CPU board in the Northstar.
    So the rest of the I/O in the Northstar is in the same place. I used the terminal output of the Northstar.

    Before I tested the Tei CPU board in the Northstar I've tested the Tei computer itself with all the Tei boards I have. (CPU, serial and mem)
    And in that original configuration nothing shows up at a serial port of the Tei. So I wonder if that is because of the missing FDC...
    The EPROM should have the config data for the three 8251 uarts on the TEI I/O board. Otherwise it could never display a startup text.

    On the other hand, if I only swap the Northstar memory board with the Tei memory board, the Northstar refuses to boot either...
    I wonder if there is a difference between the memory boards. Or maybe a defect in the Tei memory board.
    ( I have an expandoram board which works in my 'Altair' but this card also doesn't work in the Northstar
    And the Northstar memorycard doesn't work in my Altair... On the expandoram is a 8080 setting. What's the difference?)

    Quote Originally Posted by glitch View Post
    Of course, if the monitor ROM isn't signing on, and you haven't changed any switch settings on the serial I/O board, there may be something wrong with the I/O board, or your serial cables, et c. I'd attach a serial light box to the port and figure out if it's something as simple as needing a null modem cable, first!
    Yes, baby steps... Now I know the CPU board is doing at least something...
    Last edited by Roland Huisman; June 18th, 2017 at 06:47 AM.
    WTB: Case for Altair 8800 ...... Rolands Github projects

  4. #14

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    Still searching for a Tei FDC-2 or FDC-3 floppy controller and the schematics + software for that board.

    Did anyone find a similar system in the past years? It would be great if
    someone could help me to find more info about the system and boards...

    Thanks, Roland
    Last edited by Roland Huisman; May 3rd, 2020 at 09:58 PM.
    WTB: Case for Altair 8800 ...... Rolands Github projects

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