Exploring Application Level Timing Assessment in FlexRay based Systems

One of the motivations to adopt the FlexRay communication protocol is the increased need to integrate active safety, time-critical features into the automotive domain. A deterministic communication protocol can only provide time bounds to guarantee data availability at the network level. Exploration of the timing analysis & function allocation options for application features need to consider effects due to software behaviors such as task preemptions and interrupts, which could skew the response times during execution in ECUs. The data processing and reaction time to network data in each ECU needs to be adjusted during the development phase to achieve real-time closed loop control in adherence with the timing requirements of the application.

This paper provides an innovative approach in using FlexRay to harness the time synchronized nature of the protocol and apply its attributes to support timing assessment of distributed application functions in ECUs. A bench environment will be described, which assist in the determination of task execution time and task trigger information over a distributed set of ECUs. Such a capability would be valuable during the design/integration phase to engineers deploying distributed features over FlexRay.