This website documents the building of a computer based on the Z-80 microprocessor. The intentions of this was to have fun and learn. The project starts simple with only some ICs in a test circuit on breadboards and ends with a complete single-board computer, with ROM, RAM, I/O and storage. A minimum requirement was that it should be capable of running CP/M and being accessible through a serial interface (RS-232).

I have not yet ported any operating system to the computer, but when I do, I will post it here. Same goes with the technical documentation and other interesting things.

Specifications

Memory: 64 KiB read-write RAM, 4 KiB ROM
CPU: Z80A (4 MHz)
Peripherals:

  • 1x RS-232 (DTE, DB9S, Flow control: RTS/CTS)
  • 1x UART
  • 2x 16-bit timers
  • IDE host interface (16-bit read, 8-bit write, no interrupts or DMA)
  • 2x 8-bit GPIO output ports
  • 2x 8-bit GPIO input ports