| With the rapid development of digital television, wide band and multi-media technology, CATV integrated services network shows strong resources advantages. As a platform to extend the integrated services, digital set-top box has been becoming more and more wide application. The integration of telecommunication, television and internet is the trend of development of information technology. Digital set-top box with Ethernet access function not only can decode the television signal and shows its content and users can watch the programs with a hign definition, but also can make users to enjoy VOD (video-on-demand), surf online, Email, interactive games and so on.Based on these requirements, digital set-top box with Ethernet access function is implemented. The research and development of digital set-top box with Ethernet access function mainly include three parts as follow:(1) The design of hardware is to adopt the embedded Ethernet access solution of NIC (network interface card) DM9000A provided by DAVICOM company. The hardware design and implement of the Ethernet access model is described from circuit design and the configuration of address and bus timing.(2) The design of software includes the implement of DM9000A driver, the transplantation of LwIP protocol stack and the design of sofeware on application layer. The transplantation of LwIP protocol stack is analysed in detail, including the implement and modification of interface code between protocol stack and driver and between protocol stack and OS20. Sofeware on application layer realizes the upgrade of application data via Ethernet.(3) Integration and test to the whole Ethernet access systom. This part proposes a system testing solution, gives the test result and analyses the system performance.The Ethernet access system is based on the combination of the open source TCP/IP protocol stack LwIP and operating system OS20 to realize the receiving and sending of data. The digital set-top box not only can receive the television signal data of downlink, but also can transport the data of uplink sent out from users, which realizes the function of bidirectional communication. This reseach has a high utility value to extend the multimedia interactive application, such as the VOD (video-on-demand) and browser. |
