并行接口8255，定时/计时器8253，中断控制器8259A与计算机相连，通过8253产生1Hz的方波，并编程得到计时器，然后利用8259的中断功能和8255的并口输出数据功能做了一实时操作系统，来模拟十字路*通灯的模拟-8255 parallel interface, timer/timer 8253, 8259A interrupt controller connected to a computer, by 8253 produce 1Hz square wave, and programmed by the timer, and interrupt functions using 8259 and 8255 of the parallel output data capabilities to do a real-time operation system, to simulate the intersection traffic light simulation