【摘要】 集线器为USB设备和主机的连接提供了硬件接口。集线器本身提供的很多属性 ,保证了USB用户界面的友好性 ,并隐藏了其复杂性。集线器主要支持的USB功能有 :连接行为、电源管理、设备连接 /未连接检测、总线错误检测和恢复及支持高速和低速设备等。集线器由集线器中继器和集线器控制器组成。集线器中继器负责管理基于包的连接 ,而集线器控制器则提供状态信息和控制操作以支持主机访问。在主机和其它设备之间的连接过程中 ,集线器处于非常重要的地位。集线器能够检测到并防止任何连接错误 ,特别是会导致死锁的错误。集线器实际上也是 1个USB设备 ,它同样必须遵守USB设备的规则。更多还原

【Abstract】 Hubs provide the HW interface between USB devices and the host.The attributes supported by Hub make the USB user interface friendly and hide its complexity.Listed below are the major aspects of USB functionality that hub must support:connectivity behavior,power management,device connect/disconnect detection,bus fault detection and recovery,full and low speed device support.A hub consists of a hub repeater section and a hub controller section.The hub repeater is responsible for managing connectivity on a per packet basis,while the hub controller provides status and control,and permits host access to the hub.Hub is the essential USB component for establishing connectivity between the host and other devices.It is vital that any connectivity faults,especially those that might result in a deadlock,be detected and prevented from occurring.Because the hub is,in fact,a USB device,it must adhere to the same rules as other USB devices.更多还原