CAN FD physical layer device and CAN FD controller interface recommendations

CAN in Automation (CiA), the international users’ and manufacturers’ group for Controller Area Network (CAN), has released two CAN FD related recommendations.

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. The 16-pages document deals with that what is not covered by the ISO standards, in particular the symmetry issues of the other interface components. This includes the transceiver loop-delay, the transceiver TX delay and RX delay symmetries as well as the transmitter delay. CiA 601-1 doesn’t cover system design recommendations; they will be given in CiA 601-3, which is still under development. The CiA 601-4 ringing suppression circuitry specification for CAN FD networks is under review and will be released soon as version 2.0.

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 16-pages document doesn’t specify the time-stamping functionality. This is done in CiA 603, which will be released soon.

All CAN FD related recommendations and specifications are free-of-charge for CiA members. Non-members have to pay a lump sum of € 499,00 plus German VAT (value added taxes).