Based On Usb2.0 Virtual Test Bench Research And Development

With the rapid development of computer science and microelectronics, The virtual instrument, which is a new concept with epoch-making significance, has been put forward in the field of automatic and electronic measurement. The virtual instrument which is very powerful and potential, can be used in today's experiments to fetch up for the shortcomings of traditional instruments. The multiple virtual test instrument based on the USB2.0 interface is studied thoroughly in this thesis.Five major functions are realized in this system, such as the virtual digital-storage oscilloscope, the virtual logic analyzer, the virtual signal generator, the virtual spectrum analyzer and the virtual digital voltagemeter. First, the mission requirements of the system are introduced. Then, a research plan is proposed on the analysis of the requirements, which includes the use of the USB2.0 interface, CPLD and the USB microcontroller chip, as well as the four layers PCB design. Second, the system hardware and software are designed by the modular method.In terms of hardware, the system consists of four aspects: the virtual digital-storage oscilloscope, the virtual logic analyzer, the virtual signal generator and the USB2.0 interface. All parts of the specific hardware and principle have been studied in detail. Accroding to the knowledge, the writer designs the schematics and PCB of the system.In the term of software, four parts are included in the paper: the applications, the drivers, the firmware and the CPLD Programme. The software requirement analysis is introduced first. Then, the specific parts of software design ideas are discussed in detail, and the corresponding flow charts are given in the paper.At the end of the article, the hardware and software have been debugged individual and jointly. The design has achieved the proposed objectives and has laid a good foundation of futher studies.