The Zx Spectrum Ula- How To Design A Microcomputer -zx Design Retro Computer- New! ✧

For the Spectrum, Sinclair’s mandate was absolute: The traditional solution (a dedicated Video Display Controller like the Motorola 6845) was too expensive and required external character generators and RAM. The ZX Spectrum ULA was the answer: a custom gate array designed by Richard Altwasser of Ferranti, programmed to do just enough and nothing more .

When approaching a project, you must ask: What does the ULA actually do? In a normal computer, the CPU handles everything. In the Spectrum, the ULA is a traffic cop with a severe twitch. For the Spectrum, Sinclair’s mandate was absolute: The

in 2010, the book is the result of Smith's years-long effort to reverse-engineer the Ferranti Uncommitted Logic Array (ULA) down to the transistor level. Core Technical Focus In a normal computer, the CPU handles everything

In a normal microcomputer (like the Apple II), these tasks are split across separate chips. In the Spectrum, the ULA ate them all: Core Technical Focus In a normal microcomputer (like

: Documentation of how the ULA generates video signals, including deviations from standard PAL sync signals.