说明：  USB 项目技术报告 本文介绍了在基于ARM7 的嵌入式系统上开发USB 接口的详细内容。项目使用ARM7（MCU 处理器）和PDIUSBD12（USB 芯片）完成了U 盘的开发。主要内容涉及USB 接口的U 盘开发过程中所涉及的技术内容；重点介绍项目调试方法与步骤；并附上了自己在开发此项目过程中的一些心得与体会。
(USB project technical report in this paper, ARM7-based embedded systems development of the details of USB interface. Projects using ARM7 (MCU processor) and PDIUSBD12 (USB chip) the completion of the development of the U disk. Mainly related to the U disk USB interface development process involved in the technical content focuses on methods and steps to debug the project with its own process in the development of this project some of the ideas and experience.)