转自:http://m.blog.csdn.net/blog/luckywang1103/25244091 USB协议的第9章讲到USB可见设备状态[Universal Serial Bus Specification, Section 9.1.1, Pg 239],分为连接(Attached),上电(Powered),默认(Default),地址(Address),配置(Configured)和挂起(Suspended)6个状态.所谓可见,即USB系统和主机可见的状态,其他状态属于USB设备内…