CAN emulation in a time-triggered environment

The controller area network (CAN) protocol is a widely used event-triggered communication protocol, which offers high average performance, flexibility and extensibility. However, time-triggered protocols are becoming more and more accepted as the communication infrastructure for safety-critical applications, since they support composability, dependability and a deterministic behavior of all message transmissions. The desire to reuse CAN based legacy applications as part of time-triggered systems motivates the provision of CAN communication services within a time-triggered environment. This paper elaborates on an approach of layering CAN on time-triggered communication services. A node that participates in this CAN emulation reserves a part of its sending slot for implementing a packet service, thereby establishing a communication channel, a way of transferring a sequential data stream of CAN messages. Furthermore, the emulation offers an improved CAN communication service by addressing deficiencies of the basic CAN protocol. The CAN emulation exploits the fault-tolerance mechanisms of the underlying time-triggered system for extending CAN with support for dependable systems.