The Zx Spectrum Ula How To Design A Microcomputer Zx Design Retro Computer Portable !link! 📥

: To avoid collisions, the ULA has priority access to the "lower RAM" (0x4000 to 0x7FFF) for video drawing. If the CPU tries to access this area at the same time, the ULA halts the CPU clock, a behavior known as contention .

It scanned the rubber membrane keyboard and managed audio input/output for cassette tapes. : To avoid collisions, the ULA has priority

This is where the design of the Spectrum truly evolves. Modern retro engineers have replaced the physical Ferranti ULA with an FPGA (Field-Programmable Gate Array). : To avoid collisions