说明：  单片机做电子秒表。使用proteus仿真。设计要求：6位LED数码显示，计时单位为1/100秒。利用功能键进行启/停控制。其功能为：上电后计时器清0，当第一次（或奇数次）按下启/停键时开始计数。 当第二次（或偶数次）按下该键时停止计时，在一次按下启/停键时清0后重新开始计时。具有24秒减计数功能。
(SCM in the electronic stopwatch. Use proteus simulation. Design requirements: 6 LED digital display, time unit is 1/100 seconds. Using function keys on/off control. Its functions are: clear 0 after power-timer, when the first (or odd) Press the on/off key, start counting. When a second (or even several times) when you press the button to stop time, in a press the on/off button to clear after the start time 0. With 24 seconds by counting.)