Information on the CAN bus
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The CAN (Controller Area Network) bus system is a linear bus system that is characterized by the following features:
- Signals are broadcast in both directions.
- All bus users receive a message. Each bus user decides whether to process the message or not.
- Additional bus users can be added by connecting them in parallel.
- The bus system constitutes a multimaster system. Each bus user can be a master or slave depending on whether it is connected as a transmitter or receiver.
- The transmission medium is a two-wire connection. the cores are designated CAN Low and CAN High
- In principle, each bus user can use the bus to communicate with all other bus users. An access mechanism controls data exchange on the bus. The main differences between the K-CAN (body CAN) bus, the PT-CAN (powertrain CAN) bus and the F-CAN (chassis CAN) bus are detailed below:
- Body CAN: Data transfer rate of around 100 kBits/s. Single-wire operation possible.
- Powertrain CAN: Data transfer rate of around 500 kBits/s. Single-wire operation not possible.
- F-CAN: Data transfer rate of around 500 kBits/s. Single-wire operation not possible.
Master: the master is the active communicating node, i.e. the one that initiates communication. The master is in control of the bus and controls communication. The master can send messages to the passive bus users (slaves) in the bus system and can receive messages from them on request.
Slave: the slave is the passive communicating node. The slave is instructed to receive and send data.
Multimaster system: a multimaster system is one in which all communication nodes can take on the role of master or slave at a particular time.