The CALCULON/80 Homebrew Computer

For retro-hardware hackers, it seems that creating your own computer from chip-level components is becoming something of a rite of passage. This particular computer, the “CALCULON/80,” is based on the Z-80 processor and is designed to run the CP/M, or “Control Program/Monitor” operating system.

The CALC’ build starts out with a minimal circuit with a clock, the Z-80, and some LEDs, and progresses to having ROM, I/O, and EPROM. The discussion continues with a test program, the addition of RAM, switching out the ROM, more I/O, and other hardware considerations that should appeal to more knowledgeable hardware geeks.

For those readers that aren’t quite “hardware” enough to really digest this kind of information, there are some really good pictures, including a few of the books — remember those? — used as references for this design.

Future improvements to this project include such luxuries as a graphics and keyboard interface, and bigger and less numerous memory ICs.