Study Of Network Communication In Embedded System Of Long-Distance Transmitting Of Water Information

With the development of network communication and computer technology, the network communication of long-distance transmitting of water information has been put forward Directly putting Water Monitoring and Forecasting Equipment into network to transmit water information is the developing trendency So the author of this thesis works on embedded water monitoring and forecasting system with network communication technology research, based on the water conservancy scientific main project of the Water Ministry "study on the system of computer network measuring and controlling in irrigated district", and based on the condition of Zhulu Country, Hebei Province The Water Monitoring and Forecasting equipment can access to network by dialing-up. So we can look up water information in real time by browsing at web. Considering the development of system, realizing link to network with Ethernet mode at the same time.The software system of embedded water monitoring and forecasting equipment adopts the Real Time operating system-μC/OS- Ⅱ, and utilizes the network communication by the mode of expending network protocol into water monitoring and forecasting equipment According to the condition of limited memory of embedded system, adopts TCP/IP protocol-LwIP (light-weight) TCP/IP stack which suits to small system. In each protocol, as the date link layer the PPP protocol constitutes the network of core software with the high TCP/IP protocol This thesis mainly researches on the design and realisation of PPP network interface and Ethernet network interface.This thesis firstly introduces the hardware of this embedded system, then discusses the RTOS based on uC/OS- Ⅱ in detail. It maily discuss how to realize the network communication task : choosing the appropriate protocols; porting the LwIP to the uC/OS-II; the PPP protocol and the establishing, maintaining and closing of the PPP data-link; especially the realization of each protocol by a finite-state automation. Last it introduces the debugging circumstances, and suggests the idea of the system in the further contents and directions.