This kit is an accessory to the Single-board Z80 kit computer. It provides an LED display of the address, data, and control buses of the computer system. In addition, it provides a slow clock of about 8 cycles per second, and a single-step clock, that allow you to explore in detail the inner workings of the Z80 computer system. It also provides simple input and output ports (DIP switches and LEDs) that allow for experimentation with Z80 machine code. In all, it makes the single-board Z80 computer similar to the Original Z80 computer, but with the full 64K memory, serial interface, and disk interface of the single-board computer all functional. For details, please look at the Single-board Z80 computer bus display kit instructions.
Here is a schematic of the Single-board bus display