A novel bit stuffing technique for Controller Area Network (CAN) protocol

Control area network (CAN) is a two-wired, half duplex, high-speed network system that is far superior to conventional serial communication protocol such as RS232 in terms of functionality and reliability. CAN implementation are also cost effective. All CAN controllers in a network operate at the same frequency for safe and proper data transfer. As CAN uses Non Return to Zero (NRZ) bit encoding, long sequence of same polarity bit will cause the losses of synchronization among the CAN controller. CAN provides an effective mechanism for clock synchronization known as “bit-stuffing”. It is very difficult to predict the precise transmission time of message which leads to an adverse impact on many time critical applications. To mitigate above problem different “bit-stuffing” techniques such as XOR masking and Software Bit Stuffing (SBS) is available in the literature. In this paper a novel alternative method known as Eight-to-Eleven Modulation (EEM) technique is used for “bit-stuffing” and a comparison is brought with existing SBS technique and the superior features of EEM are established. The proposed technique is validated through FPGA implementation.