That’s pretty neat, the ULA is just a gate array after all. [Edit] I forgot to mention I have speccy and ZX81 ULAs from Charlie and they are top notch and have

That’s pretty neat, the ULA is just a gate array after all. [Edit] I forgot to mention I have speccy and ZX81 ULAs from Charlie and they are top notch and have been working flawlessly, and especially in the case of the ZX81, better than the original. Chris Smiths’ book, “The ZX Spectrum ULA: How to design a microcomputer”, is an excellent read if you like to imagine yourself as a hardware guy back in the 80’s. http://www.zxdesign.info/book/ http://www.zxdesign.info/book/