The Research And Design Of Virtual Seiral Port Based On USB Communication Device Class

USB interface supports plug and play which has unified standards, so it has a wide range ofapplications. More and more computer device use USB interface to transfer data, so how to makemany old devices to support USB interface without changing current application is becoming thehot field. USB Communication Device Class and it’s abstract control model are studied,principles of Communication Device Class and implementation techniques of abstract device arealso analyzed in the thesis. On the basis of this, design and implementation of virtual serial portdriver based on Communication Device Class are given. The overall structure andimplementation scheme of virtual serial port driver based on CDC are designed. The virtualserial port driver is made up of two parts which are communication command transfer moduleand data transmission module. The communication command transfer module satisfies thespecification of abstract control model, and the data transfer part improves the technique ofcurrent virtual serial port. The main works in the thesis are as follows: The request and transfermodel for USB protocol are studied, and the implementation techniques of virtua l serial port areanalyzed. The implementation scheme of virtual serial port driver that satisfy abstract controlmode in CDC is given. A new template for the development of virtual serial port based on CDCis brought out, and it describes some issues for the virtual serial port driver in details, at the sametime, the processing steps for virtual serial port driver is improved. The improved dataprocessing steps for virtual serial port driver is applied in the implementation of virtual serialport driver, and a stable, high-speed virtual serial port is made. At last, the test for the virtua lserial port driver on MFC is given, and the test result show that it’s function is achieved therequirement goals.