Communication by schedule
LIN (Local Interconnect Network) is designed for cost-sensitive automotive functions. Unlike CAN, communication is coordinated by one commander node that transmits frame headers according to a schedule; the selected responder or the commander supplies the response.
LIN uses a single signal wire referenced to ground. The network normally avoids complex arbitration by assigning communication slots in advance.
Key properties
- Standard
- ISO 17987
- Physical layer
- Single wire + ground
- Bit rate
- 1–20 kbit/s
- Coordinator
- One commander
- Common use
- Body electronics
What is on the wire?
The commander starts a frame by transmitting a break field, a synchronization byte (0x55) and the protected identifier. The configured publisher (a responder or the commander) then sends the response data and checksum.
The six-bit frame identifier plus two parity bits form the protected identifier (PID). A typical unconditional frame carries up to eight data bytes. Checksum calculation depends on the LIN revision and frame type; diagnostic frames have special rules.
First checks on a LIN segment
Check the commander supply, node grounds, bus waveform and the configured schedule. A missing response can mean that a responder is not powered, the frame identifier is not configured, or the line is pulled permanently high or low.
Do not add CAN-style 120 Ω termination across LIN and ground. LIN uses a different pull-up/bias arrangement; use the vehicle wiring diagram and transceiver requirements.
Typical applications
- Door and window controllers
- Mirror positioning
- Climate-control actuators
- Switch panels and small sensors
- Other low-bandwidth body functions