Everything about the CAN bus or Controller Area Network

The Controller Area Network (CAN, CANbus) technology is a communication protocol that enables robust communication between different electronic components in an embedded system. Developed by Robert Bosch and first published in 1986, this technology has witnessed considerable advancements, evolving with the introduction of CAN FD and CAN XL protocols, offering dual data rates with a higher data rate to meet latest demands. Today, CAN variants are an integral part of many microcontroller families. If you don't know much about the CAN bus, here is a historic summary of CAN since 1986.

Classical CAN

The original CAN technology, commonly referred to as Classical CAN or CAN 2.0, marked a revolution in the embedded systems industry. It presented a reliable means of facilitating communication between various units in a network. The first target market were automotive applications. However, once chips were readily available CAN migrated to virtually ALL industries.

The characteristics and specifications of this protocol are as follows:

• Data Transfer Rates: Classical CAN supports data transfer rates from 10kbps to 1 Mbps with the most common speeds used being 125kbps, 250kbps or 500kbps.
• Payload Capacity: It accommodates a maximum payload of 8 bytes per data frame, catering to basic sensor and actor data transmission requirements.
• Error Handling: Classical CAN incorporates built-in error detection and handling mechanisms (auto repeat unacknowledged frames), safeguarding the integrity and reliability of the network.
• Arbitration and Message Priority: This protocol utilizes a priority-based message arbitration method to ensure higher priority messages are transmitted first during bus collision scenarios.
• Wide Adoption: As the pioneer of CAN protocols, it enjoyed broad adoption across various sectors.

CAN FD

An extension of the classic CAN protocol, CAN FD (CAN with Flexible Data-Rate) introduces enhanced features like:

• Increased Data Payload: Supports data frames up to 64 bytes.
• Improved Data Rates: Offers increased data rates, considerably accelerating data transfer speeds. While current transceivers can handle only up to 5 or 8MBps, faster rates are still possible.

CAN XL

The latest development, CAN XL, is tailored to satisfy the escalating demands of modern automotive and industrial networks where occasionally Internet/Ethernet data needs to be tunneled through the system:

• Higher Data Throughput: Accommodates payloads up to 2048 bytes per frame.
• Flexible Bandwidth: Features adaptable bandwidth usage, promoting efficient management of high data volumes.
• Security: A CiA (CAN in Automation) security workgroup currently specifies secure communication based on CAN XL.

Implementing CAN in Your Projects

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 Embedded Systems Academy is a CANopen monitor, analyzer and simulator. It can be downloaded for free and can be used to simulate multiple CANopen devices.

At the Embedded Systems Academy, our expertise lies in offering solutions and technical know-how in CAN, CANopen, and J1939 technologies. We are adept at crafting tailored solutions to suit your specific needs. Contact us if you have any CAN or CANopen integration questions.

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.