该系统是一个简单的利用8253定时器、8255可并行通信接口和中断控制器8259设计的电子时钟系统，在该系统中设有一个启动键，启动键未按下时，显示初始化界面“HELLO”；当按下启动键时，8253定时器开始计时（8253的初值为10000，接1MHz的脉冲，即当8253计满100时正好是1S），当计时计满100时，8259便产生一次中断，在LED显示器便显示系统预先设计好的初始值“23.59.55”便开始从秒位开始加1，当加到10S时，10s位加1，加到60S时分位加1，同时秒位清零，同时怎加到24点时全部清零。-The system is a simple to use timer 8253, 8255 parallel communication interfaces and interrupt controller 8259 designed electronic clock system has a start button in the system, the start button is not pressed, the display initialization interface " HELLO"　　when you press the start button, the timer starts counting 8253 (initial value of 8253 to 10000, then 1MHz pulse, that is when the 8253 count is just over 100 1S), when the timer count over 100, 8259 will generate an interrupt , the LED display will show the initial value of the pre-designed system " 23.59.55"　started　second position start plus 1, when applied to the 10S, 10s-bit plus 1 plus 1 bit is added to 60S division, while second bit is cleared zero, how was added 24 points while all clear.