usbio通信PC端底层源代码，很适合USB初学者的底层驱动学习，配合VB或VC编写的3灯控制简易程序，使PC界面上的3颗灯或下位机上的3颗LED灯随对应的按键或控件动作而变化。-usbio Communications PC-side underlying source code, well suited to the bottom of USB drive for beginners to learn to cope with VB or VC summary prepared by the three light control procedures so that on a PC interface, or the next three lights on the 3-bit machine with the corresponding button LED lights or change the control action.