Make-a-Chip for Sinclair ZX Spectrum

Make a Chip was an educational program for the Sinclair ZX Spectrum, which became available in 1983. Written by Sinclair Research Limited, and commercialised by Incognito Software Limited, it was one of the earliest simulators made available for the home computer market, simulating digital logic gates and simple circuits.

The "Learning" part of this program introduces basic digital gates (AND, OR, NAND, NOR) and how to connect them. The gates can only have two inputs though. The "Examples" part of this program shows how to connect gates to make more circuits that are complex. Interestingly, there is an example showing how to make a memory register using basic logic blocks.

The "Experiment" part of the program enables the user to design new circuits. Since this program operated on a mere 48 KB of RAM, the limitation was 12 digital gates per circuit.

This program also has a very basic circuit debugger to let you know if the circuit is valid or if it has any errors so that you can correct it. If the circuit is valid, then you can "Run" it and provide input parameters, so that the simulation generates the outputs. If your Boolean logic is any good, you could also work out the outputs for any given inputs.

Back

It is an extremely simple program to use and you will not even need to consult your two-page manual. Simply "Load" the Software in the usual manner as you would load any program. Start your cassette player and press the "Enter" key, once the various stages of the program have loaded, it will run automatically. If you stop the program and later want to restart it again then type the command "GOTO 1", never use "RUN" or "CLEAR" commands.