The Gigatron TTL Microcomputer is a modern single-board computer built entirely from simple 74-series TTL logic chips, with no microprocessor integrated circuit at its core. Although not a vintage machine, it was deliberately designed in the true spirit of 1970s homebrew computing and early arcade hardware. In the MicroBasement, the Gigatron stands as a living tribute to the pioneering era when enthusiasts built working computers from basic gates and flip-flops, proving that the joy of transparent, understandable hardware remains alive today.
The Gigatron project began in 2017 as a creative and educational experiment by Marcel van Kervinck and Walter Belgers. The challenge was simple yet profound: build a complete, usable 8-bit microcomputer using only a handful of classic 7400-series TTL integrated circuits—the same type of logic chips that powered the earliest digital systems before microprocessors dominated. The result is a compact, elegant single-board machine that generates its own VGA video, sound, and keyboard input entirely through software running on pure discrete logic.
The Gigatron is an 8-bit machine constructed from approximately 36 simple TTL chips. Its native CPU uses a remarkably clean and minimal instruction set with 8 opcodes that expand to 17 assembly instructions through addressing modes and conditionals:
A 16-bit virtual CPU (vCPU) interpreter resides in ROM, greatly extending the capabilities of the simple native instruction set while keeping everything understandable at the hardware level.
Despite its minimalist hardware, the Gigatron delivers impressive performance. It produces 160×120 resolution 64-color VGA video and four-channel sound directly in software. A collection of built-in retro games is included, such as Snake, Racer, Tetronis (a Tetris clone), Bricks (a Breakout clone), and Tic-Tac-Toe. Most impressively, the Gigatron can emulate an Apple I computer, running authentic software including WozMon and Apple-1 BASIC. A full BASIC interpreter and compiler are also available, making it easy to write new programs and games in the classic style.
Even though the Gigatron is a modern creation, it embodies the foundational efforts of the engineers and hobbyists who created the pathways for modern computing. By returning to pure TTL logic in an age of highly integrated microprocessors, this machine keeps the hands-on spirit of the 1970s alive—showing exactly how data moves, how instructions execute, and how simple gates can create something magical. Projects like the Gigatron help ensure that the ingenuity and wonder of those early steps remain visible and inspiring, encouraging new generations to understand, experiment with, and fall in love with the raw beauty of digital logic.