1 Overview

Really! You don’t need to know how CAN works…
For the longest time the major misconception about Controller Area Network (CAN) was that it is merely used in automobiles. The truth is, CAN, since its introduction in 1986, proved to be a very attractive technology and, consequently, it found its way into all areas of applications where microprocessors are being used. Besides its undeniable use in automobiles, this does not only encapsulate industrial automation tasks, but any application where distributed control is advantageous and/or a serial bus system will eliminate excessive wiring. CAN proved to be superior to any other field-bus system in regards to low cost, the ability to function in a difficult electrical environment, a high degree of real time capability, excellent error detection and fault confinement capabilities and, almost contradictive to the previously mentioned features, ease of use. Nowadays there is no special niche for CAN; its use is universal from any industrial application, space and aviation, maritime, medicine, down to household applications such as washers, industrial dryers and even coffee machines. The ease of use is especially evident for the software engineer who is responsible for the development of a CAN based application. As a matter of fact, the actual CAN protocol, i.e. the entire data communication management including bus arbitration, error detection and fault confinement, etc,. etc., are implemented into silicon. CAN controllers know per default what to do and how to do it. The software engineer is ‘demoted’ to serve only the basic functions such as initialization, reading data, writing data, checking status and, as a result, to concentrate merely on the actual application software. This book is intended for those who are not willing to serve the unknown or those who are curious enough to find out why Controller Area Network is so easy to use and yet so extremely reliable. This first chapter introduces CAN by providing a generic overview, while later chapters will dive deeper into more detailed technical aspects. 1