Design Of CAN Bus Intelligent Node Based On Embedded Linux

Industrial control system has developed from traditional relatively independent control unit to be the current integrated network system. With constant increase of the requirements on control system, the demand for the network control system is becoming higher and higher as well.The CAN bus, as a kind of field bus, was gradually developed under the promotion of the industrial control system development. it has been widely used in industrial control system field and some other distributed control systems due to its high stability, interference immunity and simple structure characteristics,etc.Embedded technology has been widely used in various fields, including industrial control field. As the development direction of embedded system turns to be network,intelligent,visualized and high-speed, the Embedded operation system is highly demanded. Linux can be cut and is a Embedded operation system with multi-task concurrency, open source code and high performance. The Embedded Linux operation system can be used as a system software development platform in many embedded development projects.This paper presents a design of CAN bus intelligent node based on embedded Linux system, The intelligent node can check the number of nodes and communication baud rate on the CAN bus, and meanwhile, send and receive the information from the specified node to check the working state of this node. The characteristics of the CAN bus intelligent node is easy to carry, convenient to access and friendly to use.This design mainly achieves the building of hardware platform, construction of the development environment for embedded Linux operation system and the development of user graphical interface for CAN bus intelligent node. In hardware platform, there are two basic hard circuits, one is on the main controller and another is on CAN bus intelligent node. This paper introduces the hardware resources for the main controller development board used in this design, designs the hardware circuit for CAN bus node, and explains the anti-interference measures taken in the circuit; afterwards, in the construction of embedded Linux operating system development environment, this paper introduces the transplant process of Boot Loader in main controller S3C2410, the cut,compile and transplantation of the embedded Linux OS, the establishment of the root and user file system, finishes the driver software development of hardware devices related in this design; Finally, on the ground of the hardware platform operation system platform, this design develops the user interface of CAN bus intelligent node based on MiniGUI.The driver development of CAN controller in Linux OS and development of graphical interface based on MiniGUI are the two focuses and the difficulties of this design. In the development of driver software for CAN controller, firstly, we study the basic knowledge of CAN bus protocol, including the characteristics and message format of CAN bus; Secondly, we introduce the reading and writing functions of the CAN controller in the driver software; Finally, we achieve the driver development of the CAN controller based on SPI subsystem of Linux OS. In part of the development of graphic interface, firstly, we introduce the installation of MiniGUI programming environment, meanwhile, we especially introduce the development of the MiniGUI input engine; Secondly ,we explain the framework of the MiniGui application software and achieve the development of the MiniGUI application software based on this framework. this software should not only realize the user information interaction ,but also achieve the application layer control on CAN bus intelligent node.After completing the basic content of the whole design, we need to test the function and performance of the whole design. The major tasks includes: completing calibration of the touch screen, detecting the stability of the CAN physical bus, testing loading on the CAN bus intelligent node, debugging the other control function of the CAN bus and finally improving management on the data file received from CAN bus intelligent node.