N8VEM single board Z80 computer

n8vem

The N8VEM is a homebrew computer project based on the classic Z80 microprocessor. It’s designed to be easy to build using large TTL DIP components instead of SMD devices. It runs the CP/M operating system and all drives are virtual in RAM/ROM. While the base hardware is interesting, we really like the potential for expansion using a backplane. Have a look at the project’s Hardware Overview to see extra boards like the bus monitor and the prototyping board. We found out about this project on [Oldbitcollector]‘s blog; he’s using a Parallax Professional Development Board to create a VT100 terminal for the N8VEM.

Comments

  1. Looks like the guts of a Timex/Sinclair 1000 to me. Just add a membrane keyboard and a composite video output and you’re set!

  2. TJHooker says:

    I did one with a 20Mhz z80. I used another chip that had two PS/2 lines and a integrated high level NTSC controller. I was using I2C EEPROM but I wanted to find an I2C NAND solution, and maybe add a 8 core propeller chip to handle sprite routines and maybe simple physics.

    At the end of the day none of the zilog chips are really good for anything except data and signal processing; even with DRM.

  3. Arjan says:

    looks a bit like a philips pc20 plc :)

  4. markps2 says:

    I see three boards. single board? huhn?

  5. TJHooker says:

    @markps2: The bottom one is a parallax prototyping board. Looks like they’re debugging or something with it.

    I’d like to see more single board computers. People use to do them all the time in the 80s and 90s, but it was usually LED or segmented LCD interfaces. The zilog chips get interesting when you add actual frame buffer displays and file systems to the bus; especially if you’re into demoscene or modern embedded design.

  6. localroger says:

    for something a bit more modern i really like the dos-based sbc’s from jkmicro. they’re self contained like ca. 1990 desktop pc’s on a credit card sized pcb, complete with flash file system and serial ports. and a lot of standard dos programming tools work well with them.

  7. Andy Best says:

    Agreed. I’m actually working on a Z80 single board computer at the moment. I’m planning on building a custom version of CP/M, or at least a CP/M program compatible operating system. I want to build in support for FAT16 or FAT32 so it will be easier to transfer data between modern computers and the board.

    Are there any custom versions of CP/M with FAT support? I can’t seem to find any…

    Nice project though. I love the Z80 :)

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  9. c says:

    @andy_best:

    It’s really easy to transfer files to CP/M using stuff like Xmodem and Kermit!

    I revived a CP/M Kaypro 2, but I only had a cp/m boot disk with no utilities for it. I was able to send a hex copy of Kermit to the kaypro using PIP on the serial connection, then assemble it and use that to transfer files. I also upgraded the floppy drives to dual 360kb drives (and upgraded the built-in ROM). CP/M machines are really fun to play with!

  10. James Moxham says:

    Hmm that photo looks familiar?! Ah, I know why, coz I built the board at the top. Amazing where this project is going and how many people from different countries are contributing. I’m in Australia – that photo was taken in the USA. The board on top is a single board CP/M machine with onboard 448k of static ram configured as an A> drive. I know lots about that bit. There is plenty of room for Wordstar and Mbasic and Supercalc all at the same time. Plus a few games. The bit in the middle I think is a roll of solder. Down the bottom is a propeller board acting as a terminal. I’m not quite up with how that works except that it drives a vga terminal directly and has a keyboard. Since this photo was taken, the next generation has 4 serial ports and has wireless links. The generation after that will probably have the propeller chip on board so then it will be a true single board. And already someone has emulated most of the 8080 code inside a propeller, so within 6 months we could well see the whole computer inside one 40 pin chip. That is a single chip computer running CP/M with wires that connect to a VGA monitor, a keyboard and a wireless module and an RS232 port and an SD card for mass storage. This is a 100% open source project. Come join in the fun over at the N8VEM google group!

  11. Clare`Love says:

    Hmmm. I think this is where I came in.

  12. Jeff Ledger says:

    I finally catch up on my Hackaday news and long behold there’s my board. I really would have taken a better pic if I thought it would have wound up here. :) Yes, the top board is the N8VEM board, connected to the Propeller PPDB (Developement board). The roll of solder is just keeping things apart. :) The Propeller is running my VT100 terminal software, allowing the N8VEM board to use the Propeller’s keyboard, VGA monitor and SD card. I’m using a simple NULL modem connection between the two. The software I’m writing allows xmodem transfer from one board to the other at present. -Oldbit-

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  14. __sbrk says:

    Nice, but what a huge hulking beast. A friend of mine did this in a 1×2″ form factor:

    http://www.noplabs.com/cpm50/cpm50.html

  15. Gary says:

    This kludge is anything but a single board computer! The designer seems proud of the fact that he auto-routed the board??? The fact is, the main board could have been manually laid out in a few hours by any designer I have ever known (including myself), and the lay out would have been far better than any auto-router could do!

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