基于VC界面的usb通信源代码，很适合USB初学者的学习应用，实现PC与下位机的相互控制，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。-VC-based interface usb communication source code, very suitable for USB applications for beginners to learn to achieve PC with the next crew of mutual control, so that