Development Of Sensor Network Node Using DSP And UC/OS-II RTOS

Acquisition of traffic status information is the basic problem in Urban Road Traffic Control.The existing road traffic control system which takes focus on processing information in central processing computer results in the pressure of data transmission and processing.And as the deployments of bottom sensors are independent of each other,the system can not form the sensor network to acquire traffic status in whole time-space.In response to these problems,a distributed method of traffic status acquisition based on sensor network is introduced into this paper.Bottom layer adopts fieldbus CAN transmission which is high reliability and easy to form network, while upper layer uses the Ethernet communication which is high-speed and informative.The system consists of access nodes,composite nodes and a central computer.The access nodes from the bottom realize the connection of sensors of different types,and the upper central computer uses Ethernet for high-capacity data transmission,while composite nodes on the middle layer burden the functions of protocol conversion and logical layer data fusion.Sensor network nodes developed by this subject have the functions of both composite nodes and access nodes,and occupy an important position in the whole sensor network system.Considering the development costs and system performance,we have designed the hardware and software of sensor network nodes.The development and debugging of sensor network nodes include the followings.First,multi-task management and scheduling by the system are achieved by transplanting uC/OS-Ⅱreal-time operating system into the TMS320F2812.Second,system implements the acquisition of traffic status basic information by using information acquisition circuit.Third,system implements the bidirectional conversion of CAN fieldbus and Ethernet by the design of protocol conversion(CAN-TCP/IP) module.Forth, this paper takes use of CPLD auxiliary control circuit,the LCD screen and keyboard to achieve local man-machine interface control.The remote monitoring of sensor network nodes is realized by the compilation of PC monitoring software which takes VC++ as the software development platform.To verify the success of transplantation on uC/OS-Ⅱreal-time operating system and the realization of multi-task system,we have done a full experiment. By taking a large number of experiments,we also verify the correctness of the protocol conversion(CAN-TCP/IP) gateway function and traffic status information acquisition function.Finally,through the local LCD screen and a remote PC monitor interface,we get the experimental results.The sensor network nodes developed by this issue meet the design requirements and expectations,provide a reference for the further study of distributed monitoring system.