A Variety Of Research And Design Of Embedded Platforms Usb 2.0 Protocol Stack

Digital TV STB(set-top-box) has changed from just receiving the original simple digital TV signal to the new type with multi-functional characteristics. Along with the better and better performance of the digital TV STB chip and increasing functions of set-top box, users need to store more and more programs. The traditional serial port and parallel port are not available for some use, such as high-speed, hot-swappable, plug-and-play and other functions, which have been unable to adapt the requirements of the development of interactive set-top boxes. USB2.0 which is hot-swappable, flexible, compatible, with the share-type, compact size, low-cost, high reliability, power supply, high-speed transmission and the ability of plugging and playing, ,saving system resources, has become the choice of next generation set-top boxes.The paper has mainly researched different set-top box platforms, and have studied general USB2.0 protocol stack in some embedded operating system platform. Through the analysis of Windows and Linux operating system to realize the USB protocol stack, hierarchical design is used in the research. Specifically, there are two parts of work, one is to design a common model of protocol stack, and the other is to verify the feasibility of debugging in embedded platforms and ST-Linux platform ST-OS21. In this subject the STi7109 provided by STMicro-electronics is selected as the embedded decoder main chip. This dissertation is based on the DVB-S telecast criterion and satellite digital STB system. The author has accomplished the following missions with some creative points:1. For the practical application of the demand of set-top boxes, use hierarchical, modular design method, to streamline the complex USB2.0 protocol。The Mass Storage Class devices are selected, as the specific design objectives, and the use of C language programming, common protocol stack model of storage equipment is designed. In order to facilitate the users to use different platforms, the FAT file system format is used in this paper. For the operation about the file system, modules of viewing documents, creating documents, deleting files are respectively designed.2. The software platform of this paper is embedded ST-Linux operating system and ST-OS21 operating system provided by STMicroelectronics (STMicrotronics). Both systems integrate debugging tools of Sti7109 development board. In this paper a general model was debugged in the two systems, finally correct identify and document operations of U disk are successfully implemented in the two systems.