xmode协议代码，包括协议的实现方式和整个传输的过程。-The Xmodem protocol code, including the transport protocol implementations and transmission process

ymodem传输协议，c代码，在Linux系统已经验证过。在arm架构下需要自己交叉编译。(Ymodem transport protocol, C code, in the Linux system has been verified. In the arm framework, you need to cross compile yourself.)