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

The Spectrum’s ULA implements a non-transparent memory access. The Z80 runs at 3.5 MHz, but the ULA reads video memory at 7 MHz during active scanlines. When the Z80 tries to access the same address range ($4000–$7FFF), the ULA: