FlexRay

FlexRay is a new protocol designed for time deterministic, high speed, and/or safety critical applications. FlexRay nodes can only transmit at very specific times according to the design of the network. FlexRay has the ability to absolutely guarantee latency using static frames or offer more efficient bandwidth usage via dynamic frames.

Here FlexRay Messages captured with Vehicle Spy show a standard deviation of 0 on periodic rate transmission.

Since all transmit in FlexRay is based on time everyone on the bus must have the same clock. Therefore a startup procedure is defined that allows all nodes in the network to become synchronized. After startup, constant resyncronization takes place.

FlexRay also supports power management via a wake up mechanism. Sleeping nodes can wake up up on an external input and perform signaling on the FlexRay bus to wake up all other nodes.

The FlexRay physical layer signals 1's and 0's of the FlexRay protocol. It also offers a third state of idle bus.

FlexRay has advantages over CAN / CAN FD and LIN for fault tolerance, speed, and time determinism. FlexRay has disadvantages including complexity, cost, EMC, and the lack of experienced FlexRay engineers.

Visit the FlexRay Consortium Website