USB主机——硬件及软件

USB Host.──Hardware and Software

USB连接支持数据在USB主机与USB设备之间的传输。主要介绍了相关的主机接口 ,这类接口简化了客户软件与设备应用之间的通信。USB主机可分为 3层 :客户层、USB系统层、主机控制器层。USB系统层又可划分为 3个主要的组成部分 :主机控制器驱动HCD(HostControlerDriver)、USB驱动USBD(USBDriver)、主机软件。USBD通过HCD所提供的主机控制器接口HCDI(HCDIn terface) ,与HCD进行交互。USBD提供面向客户的接口 ,即USBD接口USBDI(USBDInterface) ,以供客户提出数据传送或设备配置的请求。USB主机可以提供不同的软件系统实现方法 ,完成相同的主机行为。

USB interconnection supports data traffic between host and USB device.The host interfaces are described here,which facilitate the communication between software clients on host and function implementations on device.The three layers of a host are USB bus interface,USB system and client.The USB system has three basic components:Host Controller Driver,USB driver and host software.The interface between HCD and USBD is Host Controller Driver Interface(HCDI).USBD provides host interface(USBDI)to USB devices for clients,through which clients bring forward requests for data transmission and device configuration.The host system may provide different host software implementation to realize same host behavior.