Have you heard of the LIN bus? It is often seen in automotive bus design. You might ask, “Isn’t there already a CAN bus? Where does the LIN bus come from?” The reason is simple: the CAN bus is too expensive. If an entire vehicle were to use the CAN bus, the costs would be prohibitive. Therefore, manufacturers began to invent the LIN bus. So, what is it?
1. What is the LIN Bus?
The LIN bus is a low-cost serial communication protocol based on UART/SCI (Universal Asynchronous Receiver/Transmitter/Serial Communication Interface). It is designed to provide low-end communication functions between body network module nodes, particularly suitable for serial communication between smart sensors and actuators. The design of the LIN bus aims to meet the needs of some scenarios within vehicles that do not require high-speed data transmission and complex functionalities.
2. Why choose the LIN bus in the presence of CAN?
Although the CAN bus plays a core role in automotive networks, not all scenarios require the high-speed, high-bandwidth communication that CAN provides. In applications such as windows, rearview mirrors, headlights, and door locks, where data transmission speed is slower and bandwidth requirements are not high, using the LIN bus can significantly reduce costs. Additionally, the design of the LIN bus also considers compatibility with the CAN bus, allowing for easy data interaction with the upper-layer CAN network through a CAN-LIN gateway node.
3. What are the differences between CAN and LIN buses?
Communication method: The CAN bus uses a multi-master communication method, meaning that nodes in the network can actively send data; whereas the LIN bus employs a master-slave communication method, with one master node and multiple slave nodes, where only the master node can actively send data, and slave nodes can only respond to requests from the master node.
Transmission rate: The transmission rate of the CAN bus is significantly higher than that of the LIN bus, with a maximum of 1 Mbps; while the LIN bus has a maximum transmission rate limit of 20 kbps.
Cost: Due to its simplified design, the LIN bus is much lower in cost compared to the CAN bus, making it more advantageous in cost-sensitive applications.
Node count: Due to physical layer limitations, a LIN network can connect a maximum of 16 nodes; whereas a CAN network can connect many more nodes.
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