The very first computer I owned, rather than used, was built around a Zilog Z80A processor running at 3.25 MHz. It had just four silicon chips on board and a only 1 KB of RAM. The machine had no power switch, or any other moving parts, and the built-in RF modulator output video to a UHF 625-line colour television. It cost $99.
The Z-Berry is a retro single-board computer that shares a form factor with the Raspberry Pi, but is built around the same Zilog Z80 processor as my first computer.
The Z-Berry runs at 10MHz—although 20MHz is possible—which is around two orders of magnitude slower than processor in the Raspberry Pi, but a respectable speed boost over my first computer. The board has 512 KB of RAM, along with 32 KB of ROM used to store the firmware, although it does have 17 chips on the board, rather than four.
The board uses a micro SD Card for storage and, as well as a serial interface both I2C and SPI buses are present, along with a Raspberry Pi lookalike 40-pin connector exposing almost the entire Z80 bus. The board also has a piezo buzzer, a PS/2 style keyboard connector, and is powered via a micro-USB connector. It all fits inside a standard Raspberry Pi case.
Sadly the Z-Berry is not available for sale directly, but Martin has provided a full bill of materials and instructions allowing you to build one yourself. Although right now the Gerber files for the Z-Berry PCB aren’t available, Martin has commented that they should be available in August—right now he’s working on getting the firmware, applications, and other source code, into a state where it can be shared.
While it’s not the only Z80 self-built retro-computer we’ve seen, it’s amongst the cutest. The best bit? The entire board can be put together for around $28, so less than a third of the cost of my first computer.