Design And Implementation Of Small-sized Timing System Terminal Bsaed On USB2.0Interface

USB (Universal Serial Bus) is a new interface technology that has been applied inthe computer field. It was first jointly put forward by Compaq, Intel and Microsoft inNov1994.It’s goal was replacing all kinds of PC’s I/O interfaces to simplify the PCperipheral expansion, and making the peripherals have attributes of plug-and-play andhot-plug.In this paper, the USB data flow model, device frame work and hardware andsoftware of USB host were analyzed first. And then the appropriate GPS receivingmodule and USB2.0interface chip were selected; the device drivers were programmed.With singlechip and CPLD technology, a circuit board was devised, which integratedGPS receiving and B-code decoding. It can provide second synchronization at themicrosecond level,20periods’ synchronization signals and time at0.1microsecondlevel. It can judge and display the validity of the time provider, and switch the providerwhen it’s invalid. This devise make the timing synchronization terminal small andintelligentized, solving the problem of time acquiring when the mobile equipmentworking alone.The main contents are as follows.1Based on USB2.0interface specification, analysis of the USB2.0interface dataflow model, studied USB2.0interface device architecture, as well as USB2.0hostinterface hardware and software technology. Through the above research and analysis,is established based on the USB2.0interface small time terminal design.2Based on USB2.0interface small time terminal required hardware structure andprinciple, which is based on the USB2.0interface small time terminal hardware systemdesign. Including hardware selection and composition, electrical schematic design,layout design and circuit board design.3Based on a detailed study of the USB2.0interface of the small time terminalrequired software framework and principle, were based on USB2.0interface of smalltime terminal software system design. Mainly include: the CPLD program design, MCUfirmware design, device driver design. 4Based on the USB2.0interface small time terminal application and test cases arediscussed in detail, based on USB2.0interface small time terminal interface definition,technical indicators, hardware and software installation, use and troubleshooting, thetest method, test equipment and test results confirm.