SEU sensitivity of robust communication protocols

Robust communications protocols are widely used in safety critical applications, such as aerospace or automotive systems. On-board complex systems, working in harsh environments, are composed of distributed modules with a high degree of interaction and critical tasks replication. Single Event Upsets (SEUs) are very probable to affect these modules and their communications. Robust protocols are usually designed to correct communication data errors, usually due to problems in the physical medium (e.g. noise). They provide robustness in data transmission but fault tolerance is not ensured in the interface control logic. In this work, a study of the SEU sensitivity of a typical robust communication protocol, the CAN bus, is performed. Authors have applied an extensive fault injection campaign in the internal modules of the circuit that implements this standard in order to perform a depth analysis. Experimental results prove robustness is not complete in the control part of this protocol. Selective hardening will enhance this robustness with low extra cost in terms of area or performance.