A ULA is a type of integrated circuit that contains a large number of logic gates, which can be connected to perform specific functions. In the case of the ZX Spectrum, the ULA (U8066) was designed by Ferranti, a leading semiconductor company, in collaboration with Sinclair Research Ltd., the company behind the ZX Spectrum. The ULA chip contains 22,000 logic gates, which was a significant number for its time.
If you are building a ZX Spectrum portable (often called a "ZX-clone" or handheld), you have two paths: A ULA is a type of integrated circuit
: Cheap ($4), simple PCB, USB power Cons : Hard to get cycle-perfect contention; latency for keyboard scanning; video over SPI or parallel LCD requires careful timing. If you are building a ZX Spectrum portable
It handles the "beeper" sound, the tape recorder interface for saving/loading data, and the iconic rubber keyboard matrix. Designing a Modern "Retro" Version latency for keyboard scanning