Research On The Key Technologies For Interconnection Of CAN Bus And Ethernet

CAN (Controller Area Network)bus is an effective support of distributed control or real-time control of the serial communication network, widely used because of its communications with high reliability, real-time and flexibility, CAN bus is one of the most popular fieldbus. Today ethernet is one of the most popular local area network due to the high energy and good compatibility, Top management networks of corporations are based on ethernet and TCP/IP management information network. The purpose of the paper is to solve the problem that data between two heterogeneous networks can not be compatible.The first chapter briefly introduces the features and the application of CAN bus and ethernet. Thus leads to the problem that the data between the two kinds heterogeneous networks can not be shared.That is the paper work background.We define the object and the purposes of research:Design a CAN bus-ethernet gateway, the gateway is requied to have the function that data can transmission between of two heterogeneous network. The paper also described the location of gateway in the Internet, and the role of gateway in the network.The second chapter introduces the OSI reference model and CAN bus and ethernet layer structure corresponding to the reference model.Introduce the communication theory and frame format of CAN bus and ethernet. Paper focuses on the simplified TCP/IP network transport protocol, the protocol adapt to the limited resources available, higher requirements on the rate of this feature of embedded gateway system. This lay a theoretical foundation for the design for the gateway.The third chapter gives the solution. Gateway has two effects:physical connectivity and protocol conversion. Gateway protocol conversion completed when heterogeneous networks. when the field is a large-scale monitoring network, PC machine is expensive, and traditional 8-bit and 16-bit microprocessors can not meet the rate requirements.So we select 32-bit ARM S3C44B0X microprocessor as the main controller.,select RTL8019 Ethernet controller, MCP2510 CAN controller and other peripheral devices.the hardware platform to complete the structures. Paper have gived the specific circuit diagram.The fourth chapter introduces the design procedures of each functional modules. The key source code of programming of some modules are given. The software part is divided into three parts:CAN bus and interface module, ethernet module and interface module and the OS module. CAN bus and the interface module include initialization of the design, message sending program design, receive messages program design. The paper gives the program flow diagram of design. The thernet and the interface module includes ethernet interface module design and TCP/IP module, ethernet interface module includes initialization, data transmission and data reception, the main program code is given. The implementation of TCP/IP protocol is the core of this article, the procedures of main flow chart for the various protocol modules are given. OS module includes OS operating system migration, the task set, and the main program flow diagram.The fifth chapter is the construction of the hardware test platform, download the program into the test board's FLASH, and run the program, Test results show that data transmission is normal, the gateway meet to the intended performance requirements, data in the two kinds of heterogeneous networks can be shared.In the end,summing up the current work, identify shortcomings, designing the next step work of the program.