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

If you want to design a microcomputer today using retro principles, study the evolution:

Here is the design lesson: Every optimization has a consequence. To save memory, the ULA used a "color attribute" system. Every 8x8 pixel block shared one foreground color and one background color. If you want to design a microcomputer today

Modern retro designers call this "attribute clash." 1980s kids called it "the Spectrum look." Here is the design lesson: Every optimization has

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: Modern retro designers call this "attribute clash

Design Lesson: On your own computer, decide if you want shared video RAM. For a simpler design, use dual-port RAM or separate video RAM. For authenticity, implement contention logic in your ULA.

If you want to design a microcomputer today using retro principles, study the evolution:

Here is the design lesson: Every optimization has a consequence. To save memory, the ULA used a "color attribute" system. Every 8x8 pixel block shared one foreground color and one background color.

Modern retro designers call this "attribute clash." 1980s kids called it "the Spectrum look."

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:

Design Lesson: On your own computer, decide if you want shared video RAM. For a simpler design, use dual-port RAM or separate video RAM. For authenticity, implement contention logic in your ULA.