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 as defined in ISO 11898-1, December 2015. The flexible data rate capability in CAN (commonly called CAN FD) is implemented as a transport layer in order to allow for functional safety, cybersecurity, extended transport capability, and backward compatibility with SAE J1939DA.
This document facilitates the use of SAE J1939 networks utilizing CAN with flexible data rate (CAN FD) data frame format for communication use cases. This data link layer definition provides additional and unique capability compared to SAE J1939-21 to take advantage of the larger frame payload capability.
This revision includes an update to Figure 34 to match the bit positions in Figure 35.