A Low-Cost On-Line Monitoring Mechanism for the FlexRay Communication Protocol

Nowadays, communication protocols are used in safety-critical automotive applications. In these applications, fault tolerance is a main requirement and the existence of single points of failure is a serious threat to system failures. Among the communication protocols, FlexRay is expected to become the communication backbone for future automotive systems. In this paper, we identify single points of failure in the FlexRay protocol by injecting a total of 135,600 single-bit transient faults into all accessible registers of the FlexRay communication controller. The results showed that about 1.2% of all injected faults caused the controller to freeze immediately. Based on these results and detailed study of the FlexRay specifications, a low-cost on-line monitoring mechanism is proposed to check freeze errors. Using this mechanism, the host controller distinguishes about 99.8% all occurred freeze errors into errors due to transient faults or due to standard operation of the FlexRay protocol.