其中id脚在otg功能中才使用。由于mini usb接口分mini-A、B和AB接口。如果你的系统仅仅是用做slave，那么就使用B接口，系统控制器会判断ID脚的电平判断是什么样的设备插入，如果是高平，则是B接头插入，此时系统就做主模式，如果ID为低，则是A接口插入，然后系统就会使用HNP对话协议来决定哪个做Master，哪个做slave 　　mini USB除了第4针外，其他接口功能皆与标准USB相同。第4针成为ID，在mini-A上连接到第5针，在mini-B可以悬空亦可连接到第5针-Where id feet otg function are used. As the mini usb interface, sub-mini-A, B and AB interface. If your system is only used as slave, then use the B interface, the system controller to determine the ID pin level to determine what kind of device insertion, if Cao Bang, B connector is inserted, then the system will call the shots mode If the ID is low, the A interface is inserted, then the system will use the protocol to determine which HNP dialogue do Master, in addition to what to do slave mini USB 4-pin, the other with a standard USB interface functions are the same. 4-pin as ID, the mini-A connector to 5 pin on the mini-B can also be connected to the first vacant 5-pin