本函数的功能是从计算机接收一串字符串，在单片机处理筛选出需要的字符串，

校检接收字符是否正确，无误后，将字符串发送回计算机-This function is received from the computer a string, in the single-chip processing out the need for screening of string,



Checking the received symbol is correct, correct, send the string back to the computer