Forget the original ULA. You need an (Field Programmable Gate Array). The cheapest and most documented for this task is the ICE40UP5K or the Xilinx XC9572XL for a CPLD, but for a full ULA+Z80, use an EP4CE10 (Cyclone IV) or an Lattice iCE40 HX8K .
The original ZX Spectrum ULA is a locked treasure chest. But by understanding its functions – video, contention, I/O, refresh – you unlock the blueprint for any Z80-based microcomputer. To build a modern portable, you don’t reverse-engineer the silicon; you re-implement the behavior in an FPGA. Forget the original ULA
A modern portable design should include: The original ZX Spectrum ULA is a locked treasure chest
If you are looking to build a portable retro machine today, follow these core design pillars: 1. The Brain (The CPU) Authentic: Use a real A modern portable design should include: If you
and the rest of the system. In any retro or portable recreation, you must account for its primary responsibilities: Video Generation: It reads the lower 6.75 KB of RAM (Video RAM) to generate a pixel display. Memory Contention: