用PIC单片机内部定时器0，作为16位定时器使用，并开启溢出中断。单片机的外部中断0引脚接开关SW2，并设置为下降沿的触发方式。可计时0SW2按键按下时，LCD上显示“Timer0 Start”, 定时器0开始工作，LED显示屏进行秒计数，再按下SW2键时定时器0停止工作，LCD上显示“Timer0 Stop”,并显示秒数，当按下SW3时，显示屏复位。-PIC microcontroller with internal timer 0, as the 16-bit timer, and turn overflow interrupt. External microcontroller interrupt 0 pin is connected to the switch SW2, and set on the falling edge of the trigger. Be timed button press 0SW2 displayed when " Timer0 Start" , Timer 0 start working, LED display counting seconds, Timer 0 stops working and then press SW2 button displayed on the LCD " Timer0 Stop" , and the LCD displays the number of seconds, when pressed SW3, the display is reset.