C8051F120 U-EC6 调试下载问题

1.“Communication could not be established with the specified adapter.
Please confirm the current adapter selection and cable connection”
2.“Target could not be reset.
Confirm cable and power connections and retry.”   3."Error:Target DLL has been cancelled.Debugger aborted!"         自己DIY的C8051f120开发板，准备用U-EC6下载，10芯扁平线按说明文档连接，电源已接，但出现以上三种错误，而不能下载，求助大虾，不胜感激，也希望能交流开发经验... 此帖出自小平头技术问答