This kit delivers a refined FPGA implementation of the Gigatron TTL microcomputer, originally built from discrete 7400-series TTL chips and ported to the Tang Nano 9K FPGA board gigatron.io hackaday.io . It includes a custom adapter board that handles video and audio D/A conversion using discrete resistors and capacitors for an authentic retro experience hackaday.io . The VGA output now leverages an improved level-shifting scheme to eliminate the unstable signals observed with the original auto level converter hackaday.io . The XC9572XL CPLD originally used for voltage-level translation has been replaced with readily available components following its discontinuation. All resistor and capacitor networks have been reorganized into a cohesive SMD-only assembly for simplified soldering and lower cost. The result is a complete, low-cost, drop-in kit that preserves every Gigatron feature while providing a smoother build and stable performance for lightweight FPGA learning.

What is it?

A ready-to-solder FPGA-based replica of the Gigatron TTL microcomputer. Includes FPGA bitstream for the Tang Nano 9K board, adapter PCB, all discrete components, and connectors. Compatible with standard VGA monitors (160×120 @ ~60 Hz) and NES-style game controllers

Why did you make it?

To overcome the original design’s VGA instability caused by its auto-conversion logic, avoid sourcing the discontinued XC9572XL CPLD, and simplify assembly by moving to an all-SMD RC network.

What makes it special?

Stable VGA output with robust level shifting Uses easily sourced, modern components in place of discontinued CPLDs Clean, all-SMD passive network for quick assembly and low cost Fully retains the vintage Gigatron instruction set, video, and audio capabilities