Fixed-Length Payload Encoding for Low-Jitter Controller Area Network Communication

The Controller Area Network bit stuffing mechanism, albeit essential to ensure proper receiver clock synchronization, introduces a significant, payload-dependent jitter on message response times, which may worsen the timing accuracy of a networked control system. Accordingly, several approaches to overcome this issue have been discussed in literature. This paper presents a novel software payload encoding scheme, which is able to guarantee that no stuff bits will ever be added to the data field by the CAN controller during transmission, and hence, lessens jitters considerably. Particular care has been put in its practical implementation and its subsequent evaluation, to show how the simplicity and inherent high performance of the scheme make it suitable even for low-cost, embedded architectures.