EX2_LEDX8: （发光二极管） P0、P2 端口的LED 先从左至右方向流水灯显示， 再从右至左方向流水灯显示，如此循环。-EX2_LEDX8: (Light Emitting Diode) P0, P2 port LED lights from left to right direction of flow shows that the right-to-left direction and then water light show that such a cycl