Everything about the CAN bus or Controller Area Network

CAN (also referred to as CANbus or CAN bus) is a network used in many every-day products consisting of multiple microcontrollers that need to communicate with each other. CAN is implemented in hardware in microcontrollers of about 25 chip manufacturers. If you don't know much about the CAN bus, here is a historic summary of almost 30 years of CAN.

The original CAN specification from Robert Bosch is available here: CAN Spec

CAN provides a safe communication channel to exchange up to 8 bytes between several network nodes. Additional network functionality like which node talks to which others, when to trigger transmit messages, how to transmit data longer than 8 byte - all of these functions are specified in so-called higher-layer protocols (in network terms, CAN is a layer 2 implementation - higher layers are implemented in software). Some of the more popular higher-layer CAN bus protocols are CANopen, DeviceNet and J1939.

The lastet add-on to the specification is called CAN-FD where FD stands for Flexible Datarate. In CAN-FD version the data size is increased of up to 64 bytes and the bitrate in the data field can be multiplied. First implementations and products are available. The specification is here: CAN-FD Spec

A list of Frequently Asked Questions also covering CAN issues are available on CANopen.us.

Usually a high-layer CAN protocol is used "on top" of CAN to provide extended functionality, such as node detection and management, various communication services. One of the popular protocols is CANopen. The educational version of the program CANopen Magic from ESAcademy is a CANopen monitor, analyzer and simulator. It can be downloaded for free and can be used to simulate multiple CANopen devices.