[51单片机系列]1.外部中断

①上电后系统复位，让后执行ljmp main跳转到main函数，然后初始化外部中断0，接着死等中断

②发生中断后，系统复位至地址0003h处，执行ljmp int_isr跳转到中断处理，接着返回，继续死等

代码:

;;;vector_addr=vector_num*8+3,0-up,1-int0,2-timer0,3-int1,4-uart,5-timer2;;;;-interrupt vector-;;power uporg 0000Hljmp main;int0org 0003Hljmp int0_isr;-main program-;org 002Fhmain:;init stackmov sp,#7fh;init int0lcall init;loop heremain_loop:jmp main_loopinit:int0_init:setb IT0;falling edgesetb EX0setb EAret;-interrupt service routine-;int0_isr:cpl P1.0retiend

仿真结果: