The Research And Application Of USB Technology In Embedded System

The Universal Serial Bus-USB, one of the most important bus specifications in PC peripheral interconnect technology, has lead a rapid development since it had been released as a industry-standard, with the its obvious benefits, such as high speed, robustness, ease-of-use, and low-cost solution. USB interface has become the most inclined standard interface for the interconnection between PC and peripheral devices, such as portable storage devices, digital products and portable communication devices.There are generally two modes of USB technology could be used in embedded systems, one is the USB device mode using as USB Devices and the other is USB host mode using as USB Host Controllers. USB devices have been used very commonly in everyday live. In industry applications, more and more data accessing systems and virtual instruments have integrated USB interface inside. With the increase of USB devices, embedded USB host and USB OTG technology have been focused on in USB application field.Because of the inequity of USB specifications, there is a great difference in the bus features between USB host and USB device, thus the realization of USB host would be much more complex comparatively. The difficulty of the complicated specifications and especially the limitation of the software and hardware in the embedded system result in that there is no enough cases with a USB host function in a real embedded system. In recent years, most embedded systems that integrated USB host function are Audio/Video player systems, such as a DVB Set-Top Box, in which a advanced micro processor was integrated. A new research field is how to integrate a limited USB host function in a low-cost embedded system, in which a micro controller was used, and this field is one of the most important subject of the paper.The paper starts with the description of USB specifications, including USB features, and then presents the USB running process, especially research on the realization of the USB functions such as high speed, robustness, ease-of-use. The following chapters are applied in research on three aspects of USB technology applications, including USB device, USB host and USB OTG.This paper consists of six chapters. The first and second chapter presents a brief description of the background of the Universal Serial Bus, including design goals, features of the bus, and existing technologies. The third chapter introduces the design of the data accessing system with USB interface in the mode of USB device. The forth chapter discusses the realization of Embedded System accessing USB Flash Disk, in which USB host controller is integrated. The fifth chapter introduces the whole design of Host-MP3 solution based on the micro controller AT89C51SND1 in which a MP3 decoder is embedded and an USB OTG chip...