CAN emulation in a time-triggered environment
Roman Obermaisser · 2002
The Controller Area Network (CAN) protocol is a widely used event-triggered communication protocol, which oers high average performance, exibility, 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 oers an improved CAN communication service by addressing deciencies of the basic CAN protocol. The CAN emulation exploits the faulttolerance mechanisms of the underlying time-triggered system for extending CAN with support for dependable systems.