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FlexRay Description

FlexRay is a high-speed serial [Synchronous and Asynchronous] communication system for in-vehicle networks [Control Systems] using Point-to-Point [Star topology] links, at 10Mbps [Fault-Tolerant] over Un-shielded Twisted Pair [UTP] or Shielded Twisted Pair [STP] cable.
The FlexRay bus defines the Physical layer [Electrical and Optical] and Protocol, under separate specifications.
FlexRay is a fault tolerant bus and provides deterministic data transmission at a Baud-Rate of between 500kbps to 10Mbps with a 24 bit CRC.
Although the specification does indicate to keep the data rates between 2.5 and 10 Mbps.
FlexRay is a time-triggered bus; electronic systems communicate continually in pre-defined time slots on a data bus.
The Electrical Physical layer uses Non Return to Zero (NRZ) bit encoding for data communication on an Optical bus.
The use of NRZ encoding ensures compact messages with a minimum number of transitions and high resilience to external disturbance.
The Network Topology used by FlexRay point-to-point connections via linear passive busses and passive stars up to active star topologies.
Although the specification declares that all topologies are linear.
FlexRay is an extended protocol version of byteflight. Applications for FlexRay include; steer-by-wire and brake-by-wire.

The FlexRay Consortium [www.flexray.com] closed operations in 2009.
FlexRay Communications System Specifications Version 3 [2009]

FlexRay Protocol Specification Version 3.0.1
FlexRay Electrical Physical Layer Specification Version 3.0.1
Including conformance testing specifications for both the physical and protocol levels.

FlexRay Interface ICs

austriamicrosystems AG
{FlexRay Active Star Device, standard Transceiver; AS8220-AS8221-AS8223}

Care should be taken when implementing a FlexRay interface, as the Consortium has ceased operations.
There is no evidence that the specification is being picked up by another standards organization.
There will be no way for the standard to be updated or corrected with no support from a national standards organization.

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