What is it?

This is a simple Z80 CPU tester based on the idea of executing NOP instruction. Data bus signals are grounded and CPU executes NOP instructions in an endless loop from 0x0000 to 0xFFFF address space. It can be used for basic functionality tests of Z80 compatible CPUs. Works with all NMOS and CMOS types. There are two test modes available, default FAST mode to see activity on all address signals A0-A15 or SLOW mode for better visualization to observe single program counter increments. (keep the SLOW button pressed). Don't be surprised to see A7-A15 signals flashing fast in the SLOW mode. Z80 executes a periodical memory refresh cycle, that is standard feature of a Z80 CPU. The device is powered over Mini USB cable (not supplied).

Why did I make it?

If you have a drawer full of Z80 CPUs or just a few pieces, this is the right tool for you.

What makes it special?

Easy to operate, small and compact design.