CAN stands for Controller Area Network, it is used to allow microcontrollers and devices to communicate with each other within a vehicle without a host computer which allows for control and data acquisition. These devices are also called Electronic Control Units (ECU) and they enable communication between all parts of a vehicle.
Today, you can find up to 70 ECUs in a modern car, e.g. the engine control unit, airbags, audio system, etc. CAN is a serial communication bus designed for industrial and automotive applications. For example, they are found in vehicles, farming equipment, industrial environments, etc.
The role of CAN bus
Without the CAN protocol, electronic modules in vehicles will have to communicate with each other using direct, point-to-point analog signal lines. It will eventually cause a messy excessive amount of wiring and unreliable communication between devices. Excessive wires may require additional equipment, which also creates cost issues.
With CAN protocol, it eliminates the need for all these wirings by enabling electronic devices to communicate with each other with a single multiplex wire that connects each node in the network to the main dashboard.
The multiplex wire and architecture enable signals to be combined and transmitted over the entire network with just a single wire while ensuring each electronic module in vehicles receives data from sensors and actuators. This allows the user to be able to connect any number of ECUs in your vehicle through the two-wire bus.
The key benefits of CAN bus
Simple & Low cost
ECUs communicate via a single CAN system instead of via direct complex analogue signal lines - reducing errors, weight, wiring and costs
Centralized
CAN bus supports centralized control over ECUs, it enables central diagnostics, data logging, and configuration.
Robust
The system is robust towards electric disturbances and electromagnetic interference-ideal for safety-critical applications (e.g. vehicles).
Efficient
CAN frames are prioritized by ID so that top priority data gets immediate bus access, without causing interruption of other frames or CAN errors.
CAN bus history in short
Pre CAN: Car ECUs relied on complex point-to-point wiring
1986: Bosch developed the CAN protocol as a solution
1991: Bosch published CAN 2.0 (CAN 2.0A: 11 bit, 2.0B: 29 bit)
1993: CAN is adopted as an international standard (ISO 11898)
2003: ISO 11898 becomes a standard series
2012: Bosch released the CAN FD 1.0 (flexible data rate)
2015: The CAN FD protocol is standardized (ISO 11898-1)
2016: The physical CAN layer for data rates up to 5 Mbit/s standardized in ISO 11898-2
Today, CAN is standard in automotive (cars, trucks, buses, tractors, ...), ships, planes, EV batteries, machinery and more.
Motivation to CAN FD
With the constantly growing amount of electronics and data being communicated in modern-day vehicles, the CAN with Flexible Data-Rate (CAN FD) protocol was created to meet industry and consumer demands.
Specifically, CAN FD offers three benefits (vs Classical CAN):
It enables data rates up to 8 Mbit/s (vs 1 Mbit/s)
It allows data payloads of up to 64 bytes (vs 8 bytes)
