USB in a Nutshell(USB概述)Making Sense of the USB StandardStarting out new with USB can be quite daunting. With the USB 2.0 specification at 650 pages one could easily beput off just by the sheer size of the standard. This i s only the beginning of a
usb-in-a-nutshell 英文版
USB协议太厚了，这个英文版资料对USB协议做了简单梳理。只做USB设备开发，可以直接先看这个。
(1) most of us are here to develop USB peripherals and (2) it's common to read a standard
and still have no idea how to implement a device. So in the next 7 chapters we focus o
