Spectrum Ula — The Zx
The "Uncommitted" part of ULA is key. Ferranti would manufacture a silicon die containing a fixed array of unconnected NAND gates, inverters, and flip-flops. The final "commitment" was a single metal layer that connected these components into a specific circuit designed by Sinclair.
If you are looking for academic-style papers or guides beyond Smith's book, you may find the following useful: the zx spectrum ula
The ZX Spectrum ULA (Uncommitted Logic Array) - a crucial component in one of the most iconic home computers of the 1980s, the ZX Spectrum. Designed by Acorn Computers and manufactured by Texas Instruments, the ULA played a pivotal role in the machine's graphics and sound capabilities. The "Uncommitted" part of ULA is key
