Java 2 Ada

Z80 Board

Version 5 by Stephane Carrez
Project Z80 Board connected to the French minitel
Date 1986 - 1987
Goals Create a computer board that could be used to program and play with


In 1987, I've designed a small Z80 board that I could connect to a French minitel. The z80 board had:

  • A z80 cpu running at 2.4576Mhz.
  • A z80 dma (in fact I've never succeeded in using it (-:)
  • A z80 sio (1200 baud for minitel)
  • 8Kb of EPROM (2x2732)
  • 2Kb of CMOS ram, transformed into 8Kb of CMOS battery saved ram on an expansion board.
  • The z80 board was realized in wrapping technic.


Z80 Board


Schemas are available but they are written by hand.


The prom monitor took 4Kb and I've used ancien programming technics with hand assembling, binary copying from one eprom to the other to insert code or do patches. The software was entirely written on paper because I had no computer to write anything at that time. Once written on paper, I have assembled it manually by looking at the Zilog manual. The monitor was then burned by typing the hex code.


1999: Last time I powered on the board.... It still worked... but for some reason it was resetting
1987: Created the board in 2 days (wrapping) and the monitor in many days. It was fully functional. However I have never manage to make the Z80 DMA work. I don't know if it was a hardware or software problem.
1986: First idea and wrote the schematics