..\OBJ\KEY.axf: Error: L6915E: Library reports error: __use_no_semihosting was requested, but _ttywrch was referenced
勾选上，再编译就OK了！
002——keil-Error: L6915E: Library reports error: __use_no_semihosting was requested解决
原文：https://www.cnblogs.com/luxiaoguogege/p/11846620.html