The Research And Implementation Of WEB Server Based On LWIP

In recent years,with the development of embedded systems,a variety of embedded devices has been widely used in household,industrial,military and other fields.at the same time,a variety of embedded devices are also need the use of the Internet to send the information quickly and easily spread to any of the locations urgently, in order to achieve remote control. How to realize the embedded networking in the embedded devices of limited resources has become an important question that needs to be paid attention and researched.While many people domestic and overseas are focusing on combing embedded systems with Internet,some difficulties still exist including:first,many communication protocols of Internet raise higher demand of memory and operation speed,while many existing 8-bit and 16bit MCU(micro controller unit),except 32-bit MCU,have difficulties in running TCP/IP protocols;second,there are various kinds of MCU in the fields of application of embedded system and if you want to realize the networking function on MCU,you have to be very familiar with the framework specialty of this type and relating programming language,but there are some differences between different types of MCU;third, Today, in a number of control areas, use the CAN,RS232,bus network to achieve the exchange of information between the MCU. the bus network will be an effective radius is limited,less communication protocol,and isolated from the outside Internet, in the base of this status quo,this dissertation proposed the embedded WEB server,through the WEB technology,the information will be send in the form of WEB pages to any where dynamicly and quickly,so that embedded Internet become a reality.Based on thorough analysis TCP/IP protocol stack, this thesis designed an operating simulation layer between LWIP and operating system,which provide system service.Because system call and data structure with operating system concerned were not adopted,in addition to, which also provided an bottom interface layer,which provide various device drivers for different hardware,should inculde such funtion as system initiation,ethernet initiation,thread receiving,data packet reading and sending.The traditional embedded WEB server uses dynamic exchange of technology, but it is very unrealistic for lack of resource extreme of embedded system, Therefore this paper put every browser requests as a function request, each request has the corresponding function, when a new request increases, easily realize open good dynamic WEB services by simply adding corresponding processing function.Finally,the testing design architecture was presented in this thesis to test the transplant protocol in ARM development board andμC/OS-Ⅱoperating system. By the analysis of the experimental result,it allow users to be able to control the embedded system in real-time through Internet WEB server,the design of embedded WEB server accords with the needs of the embedded devices and network technology development,which has good value of the theoretical study and the broad marketprospect.