USB连接不稳定

问候语！我试图通过USB连接PIC32 MX470F512H到PC。我使用的是USB CDC和声库，我的项目是基于CDC*COMLPORTA的一个例子。问题是我的联系不稳定。当我打开PCB时，我的PC找到了设备并安装了驱动程序。在30到40秒内一切都很好，之后PC显示了设备管理器对USB设备的一个感叹号。它说“设备不能启动（代码10）”。如果我重新连接设备，错误就会留下。我必须为PCB解除1530分钟的电源，所以PCB再次发现只有30到40秒才正确。我想我有一个硬件问题。这里是我的连接：VUSB3V3（引脚35）和Vu***（引脚34）都连接到PCB VCC（3，3V）。GND & GT；USB端口PIN 4D+-GT；USB PIN 3D -GT；USB PIN 2USB引脚1。怎么回事？谢谢！



      以下为原文

    Greetings! I`m trying to connect PIC32MX470F512H to PC through USB. I`m using USB CDC HARMony library and my project is based on cdc_com_port_single example. The problem is my connection is unstable. When I turn on the PCB, my PC finds the device and installs the driver. Everything is fine for about 30-40s and after that the PC shows a exclamation mark in the device manager right to the USB device. It says "device cannot start(code 10)". If I reconnect the device the error stays. I have to unpower the PCB for 15-30min so the PCB to be found correct again only for 30-40s.
I think I have a hardware problem.
Here are my connections:
Vu***3v3(PIN 35) and Vu***(PIN 34) are both connected to PCB Vcc(3,3V).
GND->USB port PIN 4
D+ -> USB PIN 3
D- -> USB PIN 2
USB PIN 1 -> unconnected
Any ideas what`s going on?!
Thanks!