The CiA with the help of OEMs, Tier1 and CAN FD chipmakers have created the CiA 601-1 and CiA 601-2 documents in order to achieve interoperability between CAN FD devices.
CiA 601-1 recommends the physical layer design for CAN FD device interfaces. It is based on the ISO 11898-2:2016 standard, which specifies the CAN FD transceivers and addresses points which are not covered by the ISO standard like the symmetry issues, transreceiver loop, TX and RX delays. This document does not cover system design recommendations (which will be in CiA 601-3).
CiA 601-2 provides guidelines for the CAN controller interface to the host controller. Besides special states and modes, it recommends the control and status interface, the bit-timing configuration parameters including those for the secondary sample-point.
The CiA 601-4 ringing suppression circuitry specification for CAN FD networks is
under review and will be released soon as version 2.0.