You have just designed the core of a retro computer. Your FPGA ULA will be faster, cooler, and more reliable than the original—but it will emulate the limitations perfectly (including the color clash, because that is the "flavor" of the machine).

Use a Z80 CPU or an IP core that acts as a Z80 processor.

Software support came from Steve Vickers (of Nine Tiles Ltd), who adapted Sinclair BASIC from the ZX81 and wrote the Spectrum’s ROM firmware. Together, Altwasser and Vickers created a machine that was both affordable and capable, attracting a generation of programmers and gamers.

For retro computer enthusiasts and electronics designers, the ZX Spectrum ULA offers a fascinating case study in design and development. By recreating the ULA using modern technologies, enthusiasts can gain a deeper understanding of the original design and appreciate the ingenuity of the Ferranti Electronics team.

The semiconductor manufacturer (Ferranti, in Sinclair's case) created a standard silicon wafer containing an uncommitted grid of logic gates (AND, OR, NAND, NOR).