说明：  //本函数实现在STC12C2051上自发自收的功能 //例如在串口调试助手打上十六进制发送，十六进制接收 //在发送窗口上写上12，在接收窗口上就会显示12
(//This function in the spontaneous self-admission STC12C2051 function// for example, marked with serial debugging assistant hexadecimal send, receive hexadecimal// in the sending window to write on the 12, in the receiving window will appear 12)