Many of us will have at some point encountered a Z80 microprocessor, whether we’ve bare-metal programmed for it, or simply had a go at blasting some invaders on a game system using one. Like all the processors of its era, it’s got a relatively simple and accessible internal block diagram, so there’s a good chance that readers well even know how it works, too. But do any of know how it really works, down to the gate, transistor, and net level? [Goran] does, because he’s written a Z80 netlist simulator that allows the running of code alongside the examination of the chip and its signals. It’s not particularly fast, achieving a modest 2.3kHz clock speed when run of a fairly high-end PC, but we’re guessing readers needing to run Z80 code for anything other than learning would use the real thing anyway.
There’s a video of the software in operation which we’ve placed below the break, and we can see it will be a fascinating tool even to people who aren’t dedicated reverse engineers. To be able to bring up a logic analyzer view of the internals of a processor while it is in operation is truly astounding if you are used to it as a black box, and to have logic diagrams at your fingertips rather than puzzling out individual transistors really gives a window into what is going on.