ZX Spectrum ULA

The ULA, or Uncommitted Logic Array, chip was a key component of the ZX Spectrum. It was responsible for controlling the video display, keyboard input, and other low-level functions of the computer.

The ULA was a custom-designed chip that was created specifically for the ZX Spectrum. It allowed the computer to perform many of its basic functions in a very efficient manner, despite its low cost and relatively modest specifications.

The ULA was responsible for generating the video signal that was sent to the computer’s display. It performed this function by using a technique called “bit slicing”, which allowed it to generate a high-resolution display using a relatively small amount of memory. The ULA was also responsible for handling keyboard input, as well as other low-level functions such as memory management and interrupt handling.

A modern replacement can be found here:

Charlie Ingleyhttps://www.tindie.com/products/charlieingley/vla82-spectrum-48k-ula-replacement/
ZX Renewhttps://zxrenew.co.uk/ZX-Spectrum-replacement-ULA-p151287223