用D12做的模拟U盘的源代码，有电路图，插入电脑后能检测到U盘，但是不能读写，对开发U盘读写模块的有帮助。-D12 done with the simulation U disk source code, circuit diagrams, computer inserted after detecting USB However, we can not read and write, to the development of U-Disk Module help.