The Zx Spectrum Ula How To Design A Microcomputer Zx Design Retro Computer Portable =link= Jun 2026

In early microcomputers, generating a video signal, handling keyboard input, and managing memory required dozens of separate logic chips. Sinclair Research eliminated this bulk by using a custom Ferranti ULA chip.

: The ULA reads 40 bytes of screen data per line (6.5 µs fetch) then the Z80 runs (6.5 µs). This “contended memory” model is the single most difficult feature to emulate accurately. In early microcomputers, generating a video signal, handling