The Design Of Integrated Access System Based On Ethernet

With the fast development of telecom and internet techniques, it is clear that the telephone network and packet data communication network will converge into NGN (Next Generation Network) in the near future. The Integrated Access System, which can provide integrated access services of voice, data and video, will replace all kinds of access devices nowaday. It will bring users the reliable and low-cost VoIP, VOD and other data services. So it is of high importance to research on how to design and implement the Integrated Access System.This thesis is mainly organized around the design and development of Integrated Access System based on Ethernet. Firstly, an overview of current condition and trends of broadband access technology is taken. And then the structure design of the system based on Ethernet is introduced. At last the design and realization of hardware and software are described in detail.The structure of hardware is mostly made up of two parts, main processor circuits and periphery circuits. The main processor circuits consist of the embedded processor in AD6834, SDRAM and Flash. SDRAM is used as the internal memory space of the embedded operating system and the application programs. Flash is the storage of image of the OS kernel, the systemic configurations and programs. The periphery circuits include Ethernet switch circuit, VoIP circuit, power supply, WLAN circuit and CPLD. Then, after the related interface and main selected chips are introduced, the design of all hardware parts is discussed in detail. Also, the way to design the PCB layout of the board with the Cadence design tool is given.Finally, the idea of software architechtecture and the development of the BootLoader for the Integrated Access System are presented.