[implements]

There’s an interesting blog post about how a far simpler machine generates its video signal, if people are curious about the signals involved:

http://blog.tynemouthsoftware.co.uk/2023/10/how-the-zx80-gen...

“The CPU then only produces a TV picture when BASIC is waiting for input (or paused). At other times it does not bother to produce a video picture, so the CPU can run the program at full speed.”