| At present,the function of portable equipment and the ability of data processing become morepowerful. Nor Flash ,Nand Flash and mini hard disk are popularly used in Embedded system, and thevolume of them increases quickly. for example, the volume of some portable equipment is more than 20G..Universal Serial Bus is a protocol of transmission . it supports three types of transmission speed and fourmodes of transmission. The High-speed bulk transmission in USB 2.0 protocol can meet the requirementthat the data capacity is very large in PMC, and Mass Storage Class in USB protocol also aims at mass ofdata transmission. So research on USB 2.0 protocol and Mass Storage device is practical.This project is based on The Portable Multimeida Center,The Intel XSacle Pxa255 is the CPU andGnu/Linux2.4.19 is a operation system .the USB controler is Netchip NC2272. this document is mainlyparted as following.The protocol of USB is researched.The protocol of USB Mass Storage Class is researched.Because USB Gadget function is not implemented in linux kernel of 2.4.19 version, to increase thespeed of the transmission,so USB2.0 device communicate with hard disk direct.Because root partions of the Linux OS is base on hard disk,so must do something to protect it ,to avoidmodification.Realize the function of hot plug.Realize a FAT file system image,by this debug is simple,and can detect the speed of translation fromthe Fifo of USB controller to SDRam.Do something to test the funtions and capability of usb device.At present, works described in this thesis is completed.this equipment with USB can support byWindows 2000 , XP of Microsoft and Red Hat Linux9.1 of Red Hat Corp.the speed is 2.5MByte/s. |
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