A controller area network (CAN) is a bus standard designed to allow microcontrollers and devices to communicate with each other in applications without a host computer. It is a message-based protocol, designed originally for automotive applications by Bosch, though it is also used in many other contexts.

 

CANs provide an inexpensive and flexible method for various devices to communicate via electronic control units (ECUs) by reducing the wiring required between each device. Each device simply connects to the CAN bus and transmits and receives messages accordingly. Signals are sent to all devices using unique identifiers. If the device deems the message relevant, it is processed and received, if the messaged is deemed non-pertinent, it is simply filtered out. Without the CAN, each device in the network would be required to be physically connected in order to transmit and receive signals.

 

The CAN is also able to determine priority for each signal transmitted along the bus. If multiple devices try to transmit a message onto the CAN at the same time, the higher priority will automatically get access.