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

Using Smith’s findings, modern engineers have recreated the ULA in Verilog for FPGAs. The recreation revealed that the original ULA had a hidden "test mode" (activated by floating pin 27) that outputs internal scanlines—proof that Ferranti engineers built in debug hooks that Sinclair never used.

Keywords integrated: ZX Spectrum ULA, how to design a microcomputer, ZX Design retro computer. Using Smith’s findings

You cannot buy a Ferranti ULA today. But you can design its modern equivalent using: how to design a microcomputer