The CAN is a network that can be compared to a vehicle’s nervous system, allowing the different components connected to it to communicate. These component play a similar role to body parts, with the CAN bus forming the connection between them. In a properly designed CAN, data reaching one Electronic control unit (ECU) can be transmitted and received by all others. To learn more about can bus interface, contact Pertech Embedded solutions.
ECUs can represent the reverse drive warning system, the airbags, the audio system and so forth. There may be dozens such units in a modern vehicle and each one of them might need to feed and receive information with the other units in the network. Fortunately, the can bus standard can enable this communication without overly complex and customized wiring. One standard is simply used for all components.
The ECU accordingly prepares and broadcasts sensor data, external or internal, through the CAN bus. The transmitted information reaches the other ECUs with the parameters programmed into each determining response.
The controller area network is classified into two layers – the data link layer and the physical layer. For high speed CAN, the data link layer is described by ISO 11898-1, while the physical layer describes ISO 11898-2.
The CAN bus physical layer defines various several parameters, such as the following:
Baud rate: CAN nodes must be connected via a two wire bus with baud rates up to 1 Mbit/s (Classical CAN) or 5 Mbit/s (CAN FD)
Cable length: Maximal CAN cable lengths should be between 500 meters (125 kbit/s) and 40 meters (1 Mbit/s)
Termination: The CAN bus must be properly terminated using a 120 Ohms CAN bus termination resistor at each end of the bus
Are you interested in learning more about the can bus interface? Contact Pertech Embedded solutions. This leading company provides, among others, software components, operating systems, code analysis as well as hardware tools.
