Design And Realization Of Router Based On MPC850 And G.703 Interface

Internet is experiencing an explosive growth, and all kinds of network productions emerge in endlessly. Recently, as resource of software and hardware is perfect and mature, application of embedded system has become one of the hotspots in 21th century, whith is used in communication, automatization, information and electrical system, military affairs and so on. This paper mainly introduces the design of Router with PowerPC and embedded Linux, and realizes the function of hardware and partial software. The paper has six chapters and shows the process of design and realization.The first chapter introduces knowledge of Router, conception of embedded system and background of problem. It includes the theory and character of Router, the hardware and software of embedded system, expecially the application and excellence used in network, so Linux is choosed as software system.The second chapter introduces the controlling and application of PEB2254. There are some physical chips, which satisfies 2M interfaces, but the faction of PEB2254 is even more powerful, which not only meets El/Tl, but also fills unframe and frame and signaling in the channel. It makes Router agile in the exploitation. The chapter introduces blocks and registers of PEB2254.The third chapter introduces the hardware design of system. The blocks of system, including MPC850 and the FLASH block and the Serial block and the Ethernet block, are introduced.The fourth chapter completes the design of El interface. El is the important part in the design. It has three parts: CPU interface mainly initializes the registers of PEB2254 and inspects the work states; system interface of PEB2254 is connected serial interface of MPC850 and Time-Slot Assigner (TSA) is configured; HDLC protocol is used in SCC3 of MPC850 in order to realize the data link layer- layer 2 of OSI.The last, the interrelated registers are initialized.The fifth chapter introduces software structure of Router.It is complicated, but has basically the driver block and the routing block and the firewall block.in my paper, Router performs data conversion from 2M to 10M each other. El uses PPP protocol of HDLC, and Ethernet uses IEEE802.3 Frame Structure.Partial driver programs are given.The sixth chapter gives the environment of exploitation and debugging process. After the test of hardware and software, Router completes primarilypartial fuction.The last introduces realization and performance of Router and the next work.