USB1.1 Mass Storage类设备的研究与实现

Research and Realization of USB1.1 Mass Storage Class Device

针对嵌入式设备与PC主机大容量数据传输的需要,利用NAND FLASH存储介质设计实现USB Mass Storage类设备.通过分析PXA255处理器的USB硬件架构和Windows CE操作系统下USB软件驱动流程,解决制约Mass Storage类设备传输速度的瓶颈问题.NAND FLASH自身读写速度和USB数据传输速度是制约Mass Storage类设备传输速度的重要因素.根据USB协议规范和NAND FLASH存储介质特征,在SCSI读写命令执行过程中每次存取64 kbyte大小数据.经过测试,速度可以达到500 kbyte/s,满足快速传输数据的需要,实现提高主机与嵌入式设备传输速度的目标.

Aiming at the need of mass data transfer between embedded devices and host computer, USB Mass Storage class device is designed with NAND FLASH. USB device controller under PXA255 processor and its driver flow under Windows CE operating system are analyzed. The emphases are to resolve the bottleneck which restricts the transfer speed of USB Mass Storage device. The speed of reading or writing NAND FALSH and USB transfer is the key point that limits the transfer speed. Based on USB Specifications and NAND FLA...