Research And Implementation Of Embedded WEB Server

With the rapid development of information technology and the Internet's widespread popularity, it has become a hot application in information technology to connect varieties of smart devices based on embedded systems to the Internet for data exchange and remote control. In this topic, a scheme used by embedded systems for information exchange and remote control based on B/S structure has been proposed, and the embedded Web server construction method was mainly researched. Compared with the traditional C/S structure systems, this scheme gets the advantage of not requiring special client software, simple intuitive operation method and so on.The article first describes the development and application status of the embedded network systems, and then analyzes normal schemes to construct embedded network systems, as well as the characteristics of related software resources, which include varieties of embedded operating systems, network protocol stacks, etc. In this topic, the hardware system was based on AT91SAM7x256 processor, and the open source FreeRTOS was chose as the embedded operating system. The method of transplanting FreeRTOS to the hardware system was also studied. The widely used LWIP was used as the embedded network protocol stack. Through analyzing LWIP's working principle, process model, memory management mechanism and so on, the transplantation of LWIP to FreeRTOS, design method of NIC driver, interface between protocol stack and NIC driver as well as protocol stack start and initialization problems was further studied.In the topic's key technology aspect, through analyzing the CGI technology, which commonly used for dynamic Web server, the ideas of implementing CGI in FreeRTOS system and the design method of embedded Web server was deeply studied, including HTTP packet analysis, different treatment techniques for GET and POST requests, etc. Finally the B/S structure system has been realized, which uses the embedded system as the server, and uses the PC browser to exchange data and remote control. An application example based on this system was also designed.