圈圈教你玩USB，一本非常不错的书，推荐阅读，值得学习-Circle teach you play USB, a very good book, recommended reading, it is worth learning

目前我找到的最高清版的圈圈教你玩USB。很多其他的都是模糊的很。看的太累。-Currently I find the highest circle clean version teach you to play USB. Many others are very blurred. Look tired.