Private Serial Port Switch Design Based On Embedded Linux

This paper focuses on the communication module used in vehicle testing system.Some problemsare solved in this paper. Generally speaking, in order to realize the multiple equipments connection,multiport serial port boards should be added on conventional RS-232C serial communication systems.Only in this way, the numerous intelligent devices and remote host can be connected. However, thedata will become unrealiable in the long-distance transmission by serial communication system, andthe serial communicating net which based on the RS-232C will be much complicated. In this paper, anembedded serial port switch is designed based on ARM9and Linux, which can connect the currentintelligent devices to the Internet to accomplish the function of long-distance transmission/datacollection and control, etc.The system designed in this paper can receive data from eight serial ports and through processingthe data can be used for translating in the ethernet. Futhermore, the system allows user receiving thedata from ethernet and send to the certain serial ports by unpack, analysis, scheme transition, decision.Transparent transmission between serial terminal data and TCP/IP will be realized.Contents of this paper including:1. Detailed design of the system is developed through the analysis of the embedded serial portsexchange requirements. Embedded systerm-Linux and S3C2440A (by SUNSANG) are employedwithin the operation system.2. Hardware circuit design. The overall outline of the hardware degin is proposed, and the systemhardware is divided into four parts: processor module curcuit design, ethernet IO module curcuitdesign, serial extensional module curcuit design and communication isolation module design.3. Construction of the embedded system. Device drvier programming is emphsised and uboottransplant, Linux transplant, root file development are also involved.Ultimately, an operating platformis developed for specified embedded serial interface and provides an essential condition for the debugoperation of the application program.4. Software design. A specified program which focus on the embedded serial interface exchangeserver is developed based on Linux. And a client API function is proposed based on Windows socketwhich can provide a secondary development to the users.