编写主程序，读取K0状态，当其与地端闭合时（P1.3为低电平）初始化为下降沿中断，反之，初始化为低电平中断，且发光二极管灭；编写中断服务程序，使图中的发光管闪烁5次，间隔250ms，即中断服务程序的执行时间为2.5秒，退出中断程序时，使发光管灭。-Write the main program, read K0 state, when its end is closed and the earth (P1.3 is low) is initialized to interrupt falling