Pavel Pisa, Czech Technical University in Prague
Rostislav Lisovy, Czech Technical University in Prague
Oliver Hartkopp, Volkswagen Group Research
Michal Sojka, Czech Technical University in Prague

The LIN-bus (Local Interconnect Network) is a vehicle bus standard or computer networking bus-system used within current automotive network architectures to control slave peripherals for which CAN bus is too expensive or complex. LIN has evolved from common asynchronous serial transmission protocol and UART hardware by standardization of a message frame format.

Presented slLIN protocol driver is implemented as a TTY line discipline. An extended version of UART hardware is usually found on automotive oriented MCUs. But striving on common Linux UART/serial line discipline API allows to deliver portable solution without a requirement to implement specialized driver for each architecture/serial interface hardware. slLIN implementation portability has been tested on PC serial port and MPC5200 hardware against third party standard LIN solution.

LIN frames and configuration is accessible as a SocketCAN network device to applications. LIN is usually used in combination with CAN which interconnect LIN master nodes and use of the CAN address networking family allows to combine slLIN with SocketCAN provided broadcast manager (BCM) and CAN gateway.

The article presents even construction of a simple logic level converter from serial port to the LIN bus and set of utilities for testing and configuration of LIN network. A LIN schedule table is implemented by CAN BCM setup for LIN interface. A response cache is implemented in the slLIN protocol driver to allow fast responses and is configured by CAN messages with dedicated CAN IDs above LIN address range.