说明：  第一个状态：主干道、支干道均亮红灯5S 第二个状态：主干道亮绿灯27S、支干道亮红灯 第三个状态：主干道黄灯闪烁、支干道红灯闪烁 第四个状态：主干道亮红灯、支干道亮绿灯22S 第五个状态：主干道红灯闪烁、支干道黄灯闪烁 返回到第二个状态 其中外部中断INTO、INT1分别控制主、支干道亮绿灯
(First state: the main road, branch roads are red 5S states: main road green light 27S third state of the branch roads red light: the main road flashing yellow light, the branch roads red light flashes fourth Status: main road red light, green light of branch roads 22S state: the main road red light flashing, the branch roads flashing yellow light to return to the second state in which the external interrupt INTO INT1 respectively control the main and branch roads green light)