上面是单片机的延时程序，在单片机延时程序中应考虑所使用的晶振的频率，在51系列的单片机中我们常用的是11.0592MHz和12.0000MHz的晶振，而在AVR单片机上常用的有8.000MHz和4.000MH的晶振所以在网上查找程序时如果涉及到精确延时则应该注意晶振的频率是多大。-The above is a delay of MCU program, the program in single-chip delay should be considered the frequency of crystal used in the 51 series microcontroller we used is 11.0592MHz and the 12.0000MHz crystal, while the commonly used in the AVR microcontroller and 4.000MH are 8.000MHz crystal is why the Internet to find the program if they involve delay, you should pay attention to the precision oscillator frequency is really spacious.