这个文件定义了一个行业标准的USB接口。该规范描述了总线属性，协议定义，交易类型，总线管理和编程接口需要来设计和建造系统和外围设备与此标准的兼容。-This document defines an industry standard USB interfaces. This specification describes the bus property, protocol definition, types of transactions, bus management, and programming interfaces need to design and build systems and peripherals compatible with this standard.