The SAE J1939 documents are intended for light, medium, and heavy-duty vehicles used on or off road as well as appropriate stationary applications which use vehicle derived components (e.g., generator sets). Vehicles of interest include, but are not limited to, on- and off-highway trucks and their trailers, construction equipment, and agricultural equipment and implements.
The purpose of these documents is to provide an open interconnect system for electronic systems. It is the intention of these documents to allow Electronic Control Units to communicate with each other by providing a standard architecture.
This particular document, SAE J1939-22, describes the data link layer using the Flexible Data Rate Extended Frame Format (FEFF) with 29-bit Identifiers, as defined in ISO 11898-1, December 2015. For SAE J1939 no alternative data link layers are permitted using FEFF messages. The Flexible Data Rate capability in CAN (commonly called CAN FD) is implemented as a transport layer in order to allow for Functional Safety, Cyber Security, extended transport capability, and backward compatibility with the J1939DA.
Rationale: This document facilitates the use of SAE J1939 networks utilizing CAN with Flexible Data Rate (CAN FD) message format for communication use cases. This Data Link Layer definition provides additions and exceptions to J1939-21 to take advantage of the larger message payload capability.