定时器中断实验代码， 定时器3进行0.1秒定时，每0.5秒改变一次P2,P3口的值以产生走马灯效果。-timer interruption experimental code, three timers for 0.1 seconds regularly, every 0.5 seconds to change a P2, P3 to the values I have merry-go-round effect.