说明：  电子秒表，在硬件上实现电子秒表，主要用8279键盘/显示芯片，8259A中断控制器，8253定时/计数器以及8255A并行接口芯片
(electronic stopwatch in electronic hardware stopwatch, mainly 8279 keyboard/Chip, 8259A interrupt controller, 8253 timer/counter and 8255A Parallel Interface Chip)