| If there is USB host technique for embedded system, the application of USB devices will not leech on to PC, and the business of mobile data which is developing with a high speed will be more convenient.μC/OS-Ⅱis a widely used embedded operating system, but does not yet have USB host software functions. It is very relevant and promising to design USB host system software inμC/OS-Ⅱ.This thesis describes in details how to complete USB host system software which is based on the Open Host Controller Interface(OHCI) in ARM9 processor andμC/OS-Ⅱoperating system. In the course of the study, the first step is platform, transplantμC/OS-Ⅱto ARM according to the characteristics of ARM9 processor. Then study the principles of USB communication based on USB 1.1 protocol and some USB-related documents. In the USB host side, the software includes client software and USB host system software, and the hardware is USB host controller. The USB host controller used in this project is in line with OHCI, so it has to to read OHCI protocol document in detail and master the communication method between USB host system software and USB host controller, and complete the encoding process WithμC/OS-Ⅱat last.In this USB host system software, the control transfer and bulk transfer was realized. Control transfer is used for the enumeration of USB devices, when a USB device is connected to the USB bus. It will set the device and read the information of the device. Bulk transfer provides data transfer interface for USB devices which need to transfer mass data, such as U disk, and mobile hard disk.Finally, the USB host system software was tested by U disk, the most common USB device. Control transfer was tested by the enumeration of U disk, bulk transfer was tested by reading and writing to the U disk. |
PDF Full Text Request