The Zx Spectrum Ula- How To Design A Microcomputer -zx Design Retro Computer- ((link)) Jun 2026

Projects like the ZX Uno use FPGAs to mimic ULA logic perfectly.

Steve Vickers, the mathematician tasked with writing the ROM (Read-Only Memory) software, walked into the lab one afternoon. "The machine keeps crashing when I try to draw a circle in high-res mode," Vickers said, holding a circuit board. Projects like the ZX Uno use FPGAs to

, based on the definitive research by Chris Smith in his landmark book, The ZX Spectrum ULA: How to Design a Microcomputer What is a ULA? , based on the definitive research by Chris

Address/Bus Interface

Sinclair’s engineers, most notably Richard Altwasser, designed the specific interconnections for these gates. They sent this design to Ferranti, who manufactured a custom chip that replaced dozens of individual components. The ULA was the "glue" that held the Spectrum together, acting as the system’s traffic cop and graphical engine simultaneously. The ULA was the "glue" that held the