Image Map Image Map
Page 3 of 6 FirstFirst 123456 LastLast
Results 21 to 30 of 51

Thread: Most "accessible" CP/M Machine

  1. #21
    Join Date
    Aug 2017
    Location
    New Mexico, USA
    Posts
    113

    Default

    PM me your address, Since it is for your dad, I'll ship this 29.5MHz, CP/M-ready, Z80 SBC out to you tomorrow, free. It is an experimental design in the first place and I just managed to eliminate the nonvolatile supervisor (DS1302) and consequently jack up the clock to 29.5MHz. Passed the instruction test ZEXALL.COM in 26-1/2 minutes. Since I'm giving this one away, humor me with 15 seconds of glory by telling your father it is the fastest, simplest, and CHEAPEST Z80 CP/M computer. Not sure about the first two claims, but I'm quite positive the last claim is correct! LOL
    Bill (the other Bill) Shen
    Attached Images Attached Images

  2. #22
    Join Date
    Aug 2017
    Location
    New Mexico, USA
    Posts
    113

    Default

    Oops, the nonvolatile supervisor part number is DS1210. You can find information about the 22MHz version of this board here: https://www.retrobrewcomputers.org/d...lasmo:z80sbc64

    The 29.5MHz version software is slightly different, I'll create a dedicated page for it when I've made a board revision.
    Bill

  3. #23

    Default

    Quote Originally Posted by Plasmo View Post
    PM me your address, Since it is for your dad, I'll ship this 29.5MHz, CP/M-ready, Z80 SBC out to you tomorrow, free. It is an experimental design in the first place and I just managed to eliminate the nonvolatile supervisor (DS1302) and consequently jack up the clock to 29.5MHz. Passed the instruction test ZEXALL.COM in 26-1/2 minutes. Since I'm giving this one away, humor me with 15 seconds of glory by telling your father it is the fastest, simplest, and CHEAPEST Z80 CP/M computer. Not sure about the first two claims, but I'm quite positive the last claim is correct! LOL
    Bill (the other Bill) Shen
    wow, that's amazing, thanks so much!

  4. #24

    Default

    Quote Originally Posted by Plasmo View Post
    Oops, the nonvolatile supervisor part number is DS1210. You can find information about the 22MHz version of this board here: https://www.retrobrewcomputers.org/d...lasmo:z80sbc64

    The 29.5MHz version software is slightly different, I'll create a dedicated page for it when I've made a board revision.
    Bill
    I reviewed the schematic and setup guide, I'm guessing on the unit you're sending that the boot "ROM" code is already stored in SRAM? Set jumper to RAM boot, apply power and go?

  5. #25
    Join Date
    Aug 2017
    Location
    New Mexico, USA
    Posts
    113

    Default

    The battery-back RAM will already be loaded with software, and the jumper is set to RAM bootstrap. So just power up to the monitor, type "b2" and you'll be in CP/M2.2 or "b3" and you'll be CP/M 3.

    It turns out the board is not stable at 29.5MHz. It works well by itself, but once I put some bus load, it'll crash. So I'm sending you the 22MHz version which is well tested and documented on the link I provided.

    The connector at the board edge is not populated. It is a RC2014 bus, but RC2014 is for 7.37MHz bus, so 22MHz is too fast for most of RC2014 peripherals. You can insert a 7.37MHz oscillator and the board will work with RC2014 peripherals except the console serial baud rate will be 38.4KHz instead of 115.2K.
    Bill

  6. #26

    Default

    Or build one of Grant Searle’s Multicomp computers.

    But you’re getting away from the “vintage hardware” requirement in your OP.

    Regarding the Model 4 screen, I think it is a low resolution TV type thing. Certainly not as good as a Superbrain (I have both). But the Model 4 has a parallel port and can be fired with a cheap IDE drive (the LoTech board). There are drivers for Montezuma CP/M and TRS-DOS. On balance, that’s the way I’d go.

  7. #27

    Default

    Another option would be the Amstrad CPC 6128, although not very common in the US I believe. It can run CP/M, original disks/images are all around the internet, an external modern 3.5" floppy can be attached, decent keyboard, cheap in some parts of the planet, green mono monitors can still be found easily

  8. #28

    Default

    Quote Originally Posted by Plasmo View Post
    It turns out the board is not stable at 29.5MHz. It works well by itself, but once I put some bus load, it'll crash.
    that's a shame

  9. #29

    Default

    Quote Originally Posted by JonB View Post
    Or build one of Grant Searle’s Multicomp computers.

    But you’re getting away from the “vintage hardware” requirement in your OP.

    Regarding the Model 4 screen, I think it is a low resolution TV type thing. Certainly not as good as a Superbrain (I have both). But the Model 4 has a parallel port and can be fired with a cheap IDE drive (the LoTech board). There are drivers for Montezuma CP/M and TRS-DOS. On balance, that’s the way I’d go.
    Last year I got my dad a DE-10 Nano board loaded with MiSTer (FPGA emulation of the Atari ST et al.) Looks like Multicomp has been ported to the MiSTer platform.

    Re the TRS-80 and Kaypro: it seems that both of these machines use single sided, double density 5.25" drives - so am I correct in thinking I could write single sided images with IMD onto regular DS, DD disks in my IBM 360kB drives to be used on said machines?

  10. #30
    Join Date
    Aug 2017
    Location
    New Mexico, USA
    Posts
    113

    Default

    Quote Originally Posted by maxtherabbit View Post
    that's a shame
    I added a blank board plus a EPM7064S already programmed. So you just need to add a RAM and Z80 to have another working board. I hope you & you dad can have a father-son project together.
    Bill

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •