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

Instead of 50 discrete TTL chips (logic gates, counters, multiplexers), Sinclair paid Ferranti to draw one metal mask. The result: lower parts count, lower assembly cost, and a single chip that could be "fused" to hide your IP.

Start with a high-frequency crystal (e.g., 14MHz or 28MHz). Build your dividers early in your logic design to derive your pixel clock and your CPU clock cleanly. Instead of 50 discrete TTL chips (logic gates,

So, what does the ZX Spectrum ULA teach us about designing a computer? It teaches the art of . Build your dividers early in your logic design

Through this research, we know the ULA relies on a sequence of internal counters. As the video beam sweeps across the television screen, the ULA increments its horizontal and vertical counters. These counters act as a pointer, calculating the exact memory address of the pixel and attribute data needed for that microsecond of video playback. Through this research, we know the ULA relies

If you want to replicate the magic on an FPGA or CPLD today, here is the functional spec: