As automobiles continue to become more intelligent, safe, and comfortable, the amount of electrical systems and components continues to grow. With the addition of these components and systems comes a need for communication transceivers to facilitate their interaction in the most advantageous way possible for manufacturers. LIN was developed for this very reason: so car makers could manage communication between these components and systems in an efficient, straightforward fashion, where the bandwidth and versatility of CAN was not needed; though in most instances, it is a sub-bus to the CAN bus.
LIN® Specification Progression
The most up-to-date LIN standard was defined in 2010 (LIN 2.2A, the LIN Consortium). It was then transcribed to the International Organization for Standardization (ISO) to be accepted as ISO 17897 and officially released in 2016. Prior to 2010, LIN went through a series of revisions, being fully defined first in LIN 1.1 (1999), where the LIN Protocol Specification, LIN Configuration Language Specification, and LIN Application Interface Specification were established by a board called the LIN consortium. Each of these are necessary parts in creating the full LIN cluster in a way that is consistent across the market, allowing any car manufacturer to use the communication scheme. The LIN protocol specification describes the physical and data link layers, and the LIN Configuration Language enables the LIN cluster to be described in a file that is straightforward for any developer.
The LIN transceiver and its implementation are the focus of this paper; however, it is important to have a high-level understanding of the whole LIN network to understand the place of the transceiver in an application. As LIN became defined, it was not only specified for the actual 1’s and 0’s data delivery, but for a higher-level network implementation: The LIN workflow. The LIN workflow supports an easy-to-use, dependable implementation scheme for those working with the protocol. The configuration of the entire network cluster is defined and standardized, which is where the LIN Description File (LDF) comes in. The LDF is what differentiates the LIN clusters from each other, defining the specific use and properties for that cluster (node amount, amount and the description of message frames, message rate, and so forth). This allows the generation of software files by developers to establish what task each node in the cluster performs. The LDF can be used to automatically generate the software involved in communication, as well as supply information for measurement and test tools involved in the LIN cluster analysis.
The LDF is written using syntax defined by the LIN Configuration Language Specification. This syntax is used in combination with the System Defining Tool to create the LDF, and thus define the whole network. Along with these tools, there is the LIN Node Capability Language, which allows the developer to define and describe the implementation of Off-the-Shelf Nodes, which are easily-implementable, general-purpose LIN nodes designed for typical applications that can be bought in large quantities.