ZI-28 8-bit Computer

Overview

The ZI-28 is my most ambitious project to date. My goal was to design and build an 8-bit computer that was usable for simple programs and games, and which could be easily expanded with hardware modules. Since I didn’t know a lot about the inner workings of a computer when I started the project in 2016, a lot of the design decisions were made as I went along. As a result, the computer will never be more than a one-off, and I would do a lot of things differently if I ever decided to design another computer.

Specifications:

• CPU: Z80 at 8 MHz
• ROM: 32 kB in two banks of 16 kB
• RAM: 128 kB, 32 kB fixed + six banks of 16kB
• I/O: Serial over USB, PS/2 keyboard, 8 expansion slots with 16 adresses each

Images