In my previous post I described an Arduino dongle and the software that can be used to clock a Z80 CPU and dump states of its buses and pins while executing a controlled set of test cases.

Here I show a trace of every single Z80 instruction as run by that setup. I also outlined some of the tests created manually that clarified few situations which were not too obvious (to me) after reading various pieces of documentation.

...continue reading "ZiLOG Z80 (un)documented behavior"


If you want to find out exactly what a venerable Z80 is doing on its bus while executing instructions, in this post I outlined a dongle and the software that will let you see that. Using just a few components and connecting them to an Arduino Mega, you can trace instructions clock by clock and observe what's happening on the bus.
...continue reading "Arduino and ZiLOG Z80"