CAN FD standards and recommendations

Since end of last year, the second edition of ISO 11898-1 is published. It standardizes the CAN FD protocol as well as the Classical CAN protocol. The standard contains what the chipmakers need to implement the protocols in silicon.

The transceiver chips qualified for bit-rates of 1 Mbit/s and higher are standardized in ISO 11898-2:2016. ISO will publish the standard within the next weeks. This document also covers the low-power mode and the selective wake-up function, formerly standardized in ISO 11898-5 and ISO 11898-6. In September 2016, ISO has published the conformance test plan for ISO 11898-1:2015 (ISO 16845-1). In the next year the conformance test plan for high-speed CAN transceivers (ISO 16845-2) will be released.

However, implementing CAN (FD) controller and CAN transceivers is just one part of the story. Device (ECU) and network design rules, recommendations, and specifications are needed to make life easier for CAN users. CiA develops the CiA 601 series providing recommendations for node and network designs. CiA 601-2, recommendation for CAN controller host interfaces, is close to be released. The CiA 603 document is intended to harmonize the time stamping of Classical CAN and CAN FD messages.

SAE has developed the J2284-4 and J2284-5 recommended practices for passenger cars. Part 4 specifies a CAN line topology for 500 kbit/s (arbitration) and 2 Mbit/s (dataphase). Part 5 is suitable for dataphase bit-rates up to 5 Mbit/s and a point-to-point communication. These documents are guidelines for OEMs and Tier 1 supplier.

CiA works on the CiA 602 series for commercial vehicles and off-highway vehicles. Part 2 specifies the mapping of J1939 parameter groups to CAN FD frames. The network design including the physical layer is not yet finalized.

In general, the CiA technical groups need to know the requirements for the desired CAN FD networks – from members and non-members. Please feel free to contact us by email service(at)can-cia.org.