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SAE J1939 specifications

Digital annex updated and CAN FD support prepared

The J1939DA specification has been reviewed and updated. Additionally, the SAE J1939 committee has continued to adopt CAN FD.

J1939 tools and protocol stacks are available from different suppliers (Photo: Vector)

In the May meeting, the J1939 task forces (TF) and the related J1939 committee reviewed as usual all J1939 documents including the digital annex (DA). The DA contains all specified suspect parameters and parameter groups. The current version was released in May. The SAE experts on J1939 meet quarterly to discuss the document improvements in detail.

Since some meetings, the TF CAN FD develops a transport and an application layer. The related protocols will be specified in J1939-22. The document describes the mapping of messages and packets to CAN FD frames, too. Autosar compatibility is one considered requirement. Therefore it may use definitions, originally described in the CiA 602-2 specification. Additionally, the TF physical layer develops the J1939-17 specification. It defines the physical network components for an arbitration phase speed of 500 kbit/s and a data phase bit-rate of 2 Mbit/s. Other specification updates still in the pipeline include J1939-16 (automatic bit rate detection process) and J1939-15 (250-kbit/s un-shielded twisted-pair physical layer). Network security (J1939-91) and functional safety (J1939-76) specifications are also in preparation.


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