In the pantheon of classic computing, few machines have inspired as much nostalgia and technical reverence as the Sinclair ZX Spectrum. Released in 1982, it brought color gaming and serious computing to the British masses at a fraction of the cost of an Apple II or Commodore 64.
Think of a ULA as a breadboard of unconnected NAND and NOR gates. You, the designer, pay for a metal mask that connects these gates into whatever logic function you need. It is a semi-custom ASIC. For a low-volume product (relative to Commodore), it was perfect. In the pantheon of classic computing, few machines
The ULA is the bus master. The CPU is the guest. Part 5: The "ULA Failure" – Designing for Reliability Ironically, the very chip that made the Spectrum cheap also destroyed its reliability. You, the designer, pay for a metal mask