{"id":448,"date":"2026-09-08T09:00:00","date_gmt":"2026-09-08T09:00:00","guid":{"rendered":"https:\/\/jellai.com\/index.php\/2026\/09\/08\/lin-a-single-wire-bus-that-runs-on-a-schedule\/"},"modified":"2026-10-15T20:43:59","modified_gmt":"2026-10-15T20:43:59","slug":"lin-a-single-wire-bus-that-runs-on-a-schedule","status":"publish","type":"post","link":"https:\/\/jellai.com\/index.php\/2026\/09\/08\/lin-a-single-wire-bus-that-runs-on-a-schedule\/","title":{"rendered":"LIN: a single-wire bus that runs on a schedule"},"content":{"rendered":"

Not every ECU needs CAN. A door module, a wiper or a headlight exchanges a few bytes now and then, and for those jobs the Local Interconnect Network, LIN, is cheaper: one wire, a simple transceiver and a microcontroller’s standard serial interface. In most applications LIN works as a sub-bus of CAN, often with the LIN commander built into the ECU that acts as the gateway.<\/p>\n

The LIN Consortium published the first specification as version 1.3. Version 2.0 followed in 2003, version 2.1 in 2006, and version 2.2A in 2010, after the consortium had closed. Since 2016 LIN has been an international standard, the ISO 17987 series, and several of its parts were updated in 2025. The new edition calls the two roles commander and responder, where earlier versions said master and slave.<\/p>\n

One wire and a pull-up<\/h2>\n

A LIN cluster is one commander and up to 16 responders on a single wire. The commander pulls the line up to the vehicle’s battery voltage through a resistor, typically 1 kΩ, and a diode; each responder has a 30 kΩ pull-up built into its transceiver. With nobody transmitting, the bus sits high: the recessive state. A node sends a dominant bit by pulling the line low. Transceivers usually work from 9 to 18 V; a typical vehicle has a 12 V battery system, some larger vehicles 24 V. The bit rate goes up to 20 kbit\/s.<\/p>\n

Every byte on the bus is framed the way a serial port frames it: a dominant start bit, eight data bits with the least significant bit first, and a recessive stop bit. That is why a LIN node can use a microcontroller’s standard serial interface rather than a dedicated protocol controller.<\/p>\n

The commander keeps the schedule<\/h2>\n

LIN has no arbitration, because only the commander starts frames. It works through a schedule table and opens every frame with a header:<\/p>\n