51单片机实现的外部中断的程序,最简单的实现,实现基本的功能,初学者可以参考一下.需要给外部中断那个引脚一个低电平,就会触发中断.-51 MCU external interrupt procedures, the most simple to achieve and realize the basic functions of reference for beginners. The need for the external interrupt pin to a low level, it will trigger the interrupt.