FPGA SPARTAN 3A Implementation of message based Arbitration in CAN Protocol

Abstract

CAN is a protocol used in Automobiles Industry. The Electronic Control Units (ECUs) in automobiles need to communicate with each other. CAN bus is used for this purpose. In a multi ECU environment, arbiter plays the most important role in CAN bus. The arbiter prioritises and synchronises the transmission of different frames of CAN bus. These frames are continuous coming from different ECUs. CAN is a message based protocol. This means, unlike other arbitration mechanisms where request signals and grant signals are incorporated to provide the arbitration, here, in this type of protocol the message ID is the arbitration field. This field is scanned and the decision of arbitration is taken.With CAN protocol, the problems of point-to-point wiring connection made for ECU communication is removed. Also, the problem of delay with alternative technologies like Ethernet is resolved by using CAN protocol. The CAN arbiter is designed using EDA tools. The tools that are used in preliminary phase of the designing are simulation and synthesis tools. The design is targeted for FPGA technology. The device family used for FPGA technology is SPARTAN 3A. FPGA implementation offers better performance with respect to speed. Also, it provides an efficient arbiter hardware, thereby reducing the size and volume.