Research And Implementation Of Embedded USB Application System

With the development of PC peripherals and digital products, the interface and connection between any two of them has become a difficult problem. Universal Serial Bus supports the feature of PNP and hot-swap, with a high transfer speed and low price. Therefore, it has been widely used in digital products, and is expected to be the interfacing standard of PC peripherals, with a bright future in communication and industrial application.With the background of the USB interface design in stored program control switching system for teaching, the paper presents a solution based on EZ-USB, in which the design and implementation of the hardware and software on both host and device sides are demonstrated in details. On the base of a brief introduction and analysis of the USB architecture and its operating mechanism, the thesis compares several prevalent USB controllers according to the requirement of the system, and brings forward a scheme based on EZ-USB. After analyzing the features of EZ-USB controller, the paper proposes the layout of the circuit design and discusses the implementation of the main functional modules, along with some extra issues such as anti-jamming, electrostatic discharge and hardware debugging. The firmware, which is essential in an embedded device, is developed in a modular way. With the firmware frameworks, the function of each part appears explicit, which simplifies the tasks in firmware development. Generally speaking, device driver is an obstacle in peripheral development. Thus the kernels in the design of device driver and client application are elaborated after the analysis of the software architecture of USB host and Windows driver model. Moreover, the latest evolution of USB specification and its future application are introduced due to the trend that the technology of computer, communication and consumer electronics is running into amalgamation.The design scheme and theoretical analysis form a base for further research, and provide reference for other embedded USB systems.