Research And Implementation Of A Data Analyzer For The CAN-Bus With An USB Interface

With the technology development of the automobile industry, especially the application of the integrated circuit and the micro-control-unit in automobile, the translated signals have become more and more complex. In order to reduce the mount of the signal lines, the CAN-bus technology has been invented and developed rapidly. By now, the CAN-bus technology has become one of the hottest points in the area of vehicle.Firstly, in this paper, the concept of in-vehicle network and development of the CAN-bus technology are introduced. The researches and development of in-vehicle network all over the world are summarized. Furthermore, the principles and applications of the CAN-bus, nowadays widely used in international automobile industry, are studied and absorbed.Then, in this paper, the USB (Universal Serial Bus) communication technology and its characteristics are introduced. As an important innovation of peripheral interface technology, an USB possesses good characteristics, namely plug and play, easily expanding, fast transmission, high reliability,flexibility and so on. It has been widely used in the PC peripheral devices and potable system.With the development of CAN-bus technology and interface technology between computer and peripherals, it is very important to set up a reliable connection between monitor computer and net nodes of the in-vehicle network. After the main points of USB protocol and CAN protocol are full researched. According to their characteristics and practical demands, a method is put forward for connecting a CAN-bus with computer by USB, namely a Data Analyzer of the CAN-Bus with USB Interface. Such a Data Analyzer system is developed to collect and display the important parameters of the in-vehicle network nodes on-line to response the status of the automobile and also analyze the automobile fault.Lastly, in the paper, the realization of the data analyzer and implementation method are discussed. The system hardware mainly uses the products of Philips Company, such as AT89C51 (MCU), SJA1000 (CAN control chip), PDIUSBD12 (USB control chip). The software programs included firmware program, windows 2000 WDM device driver and windows application, author discussed these contents respectively and detailedly. At the same time, the hardware circuits' principle diagrams and the program's codes are provided in the paper. The system can fulfill the process of data transforming and transferring between the computer and in-vehicle network nodes,meet the realtime and reliability requirements of control system for the automobile. Comparing with the designs based on traditional interfaces, it is more convenient and its speed is higher.