Dual-rate overclocking in CAN networks: A soft-core controller prototype

The CAN protocol was originally introduced for distributed automotive applications in the 1980s, and is still widely used by the industry today. CAN provides the basis for many cost-effective distributed systems, and since its first inception has proved to be a continuous area of research. Despite the fact that CAN possess many appealing features, the protocol also suffers from several significant drawbacks. One major drawback that can severely limit the applicability of CAN in data-intensive real-time applications is related to the wired-AND nature of the physical layer; this can act to severely limit the maximum transmission speed and bus length of a given CAN network. This paper and demonstration is concerned with overclocking a CAN network to improve the information throughput, whilst simultaneously maintaining the priority-driven arbitration mechanism. The paper will describe the implementation of a modified soft-core CAN-controller, in which the data transmission rate is dynamically increased to 10 Mbps during transmission of the data and CRC fields; this allows a tenfold increase in information throughput with no penalty in transmission time.