Building a microcomputer

This book is for those who want to know 

• how a microprocessor works,

• how to build more complex units from individual ICs,  

• how these units interact, and

• how this system can be programmed.


Some basic knowledge of digital signals, their basic combinations and the basic function of a flip-flop should be sufficient to understand this book. Although we will need to simplify certain things for didactic reasons, the information given in this book can be applied to any microprocessor, since the basic concepts we will address are common to all microprocessors and have remained constant despite all technical advancements.


The LoCAD app helps you to understand the functioning of a processor and a microcomputer system based on this processor by visualising the processes involved and by offering the option to integrate ("shrink") circuits. You will realise that all processes in a computer are eventually "primitive" and not that difficult to understand. 


The architecture of the microprocessor system presented in this book represents one possibility among many and has an exemplary character. It is based on the global structure of the "master model" of a computer, which goes back to the mathematician John von Neumann, and is limited to concepts which me may call classical. 


Although modern computers sometimes differ considerably in their internal structure, single-processor systems are generally designed according to the von Neumann principles. Even the basic working principle of a computer has remained the same since John von Neumann's additions. By understanding the way the model system works, you will gain the essential insights that enable you to also understand how a real processor or system works without having to learn anything fundamentally new.


The circuits shown are available for download on the website www.khloch.de in the menu item Downloads ➝ Circuits. For circuits containing more than nine elements, the full version of LoCAD is required.


If you have installed the LoCAD app and your computer is connected to the internet, you can also access the circuits directly via the link open in LoCAD.