ABSTRACT
Controller area network (CAN) is a serial communication bus protocol standardized by International Standards Organization (ISO) and designed for operation in automotive industries. It implements a unique bus access control method, called “non-destructive bitwise arbitration.” The physical medium is accessed by a producer-consumer technique based on CSMA-CD. CAN protocol has error detection, error notification, error recovery, and error confinement capabilities. Number of units that can be connected to the system is not fixed. CAN has a speed up to 125 kbps.
Different frames are used in CAN: data frame, remote frame, error frame, overload frame, and interframe space.
CAN sends message on arbitration principle. The device outputting a message on the bus during bus idle state gains control of the bus and sends the message through it. When more than one device wants to send data over the bus, a station identifier bit pattern for each device try to gain access of the bus. Configuration of the network determines the priority regarding access of the bus by a device.
When a device communicates, the high and low corresponds to 3.75 V and 1.25 V, respectively. CAN protocol is robust in the sense that it is immune to inductive spikes, electromagnetic noise, etc.
