Status Management

The purpose of status management in a LIN cluster is to detect faulty LIN nodes. The integrity of communications should be preserved in spite of any defective or faulty LIN nodes. Status management is performed centrally by the LIN master with the help of all LIN slaves connected in the LIN cluster. It is the responsibility of all LIN slaves to inform the LIN master once per communication cycle whether errors have occurred in sending or receiving LIN messages. For this purpose, a LIN slave uses a conventional, predefined unconditional frame that contains the error status within a status bit (Response_Error). The LIN slaves detect errors by bit monitoring and by evaluating the two parity bits and the checksum.

The LIN master gathers all status bits, and if necessary it initiates an error handling action. Of great interest to developers is the fact that error handling is not part of the LIN specification, and it must therefore be defined independently. The figure schematically shows the communication traffic between the LIN master and the LIN slaves needed to perform status management. The unconditional frame that transports the status bit can simply be considered a status frame. This turns the frame header into a status request, and the frame response into a status response.