The Design Of Gateway Between Ethernet And Canbus Based On Embedded System

The Field Bus, applied in the field production, is a digital communication systemwhich implements communication with characters including bi-direction,serial,multipointcommunications among measuring control equipments. It has been widely used inmany industries such as manufacture, transport, architecture, industry control and automanufacture. With developments of embedded and Ethernet technology as well asimproving requirements for its performance in modern industry, the control system,consisting of Field Bus, has become a typical model of control network in industrialenterprise network. CAN (Control Area Network) bus has many advantages including highreliability, high speed in data transmissions, longer distance of transmissions and betterreal-time signal processing, all of which make the CAN bus itself suitable for connectionof monitor equipments at industrial site. Compared with other buses, CAN bus can realizemulti-host work style; adopt non-destructive bus arbitration technology based on priority,auto repeat request, information of function and priority by identifiers.The widely application of Ethernet in Internet, makes it contain advantages includingmature technology, rich resources of both hardware and software, high ratio ofperformance and price, high transmitting speed and longer transmission distances, whichhas been widely accepted by developers and users. Connection with Ethernet in industrialequipment has largely improved the distribution of industry control systems, making upthe disadvantages of Field Bus in transmitting speed and transmission distance.Considering the superiority of Field Bus in control system at industry sites and Ethernet'scomplementary characteristics with CAN bus, it has huge practical significance to researchthe interconnection between CAN bus and Ethernet.After deeply studying the characteristics and implementation principles of Ethernet, CAN2.0B and TCP/IP protocols, this present paper proposes a gateway model whichconnects Ethernet and CAN bus, and a data processing model on the basis of queuingtheory. The present paper introduces the main contents in details, including divisions oftasks, setting of task priority, communication among tasks and event driven in embeddedmulti-task programming. This present study takes ARM as the hardware platform andLinux as the software platform to design both the hardware and software, with the aim torealize the conversion between CAN bus protocol and TCP/IP protocol as well asinterconnection between Ethernet and CAN bus, and with the permission of every user ofEthernet to have access and control to every point at site in order to realize the remotemonitoring of industrial site.This present paper takes S3C2440 processor as kernel, on the basis of the embeddedLinux platform, transplanting embedded operating system Linux, modifying Linux kernel,developing driver for CAN module and network module, and designing applicationprograms, to realize the conversion between CAN protocol and TCP/IP protocol andfinally complete the whole design of the gateway as well as realizing its functions inapplication.