Controller Area Network

Introduced in 1986, CAN is a serial field bus that is low cost, only requires 2 wires, has the ability to function in difficult electrical environments, has a high degree of realtime capability, has excellent error detection and fault confinement capabilities and is easy to use.

Controller Area Network, is a a serial network technology that is a two wire, half duplex, high speed network system. it operates at data rates of up to 1 Megabit per second.

CAN-in-Automation (CiA) is the international users' and manufacturers' organization that develops and supports CAN Standards and CAN-based higher-layer protocols.

ISO 11898 is the international federation that governs the protocol.

• Multi-Master priority based bus access
• Non-destructive contention-based arbitration
• Multicast message transfer by message acceptance filtering
• Remote data request (that no one uses)
• Automatic retransmission of messages that lost arbitration

The distance between frames is a minimum of 3 bit times.

CAN supports messages between 0 and 8 bytes.

An 11 bit identifier allows a total of 2¹¹ = 2048 different messages. An extended version allows 2²⁹ = 536+ million

The dominant level (TTL = 0V) always overrides a recessive level (TTL = 5V). This is important during bus arbitration.

A remote frame requests the transmission of a message by another node. This type of message is uncommon and CiA says to avoid its usage.

A lower message ID number represents a high message priority.