功能完善的四层电梯程序。开门停8秒，上升或者下降一层用时5秒，有五秒倒计时数码管，楼层显示数码管，以及电梯内外楼层请求显示灯。-A well-functioning procedures for four-storey elevator. 8 seconds to open the door stopped, increased or decreased when a layer of 5 seconds, the 5 seconds