1)利用51单片机作为主控制器组成一个电子跑表，采用4位LED显示器。

2)上电或RESET后显示000.0。

3)当按下START键时，作为跑表使用，显示范围是：000.0-999.9秒，当按下STOP键时，跑表停止运行，并保留所停位置的时间显示不变。-1) the use of 51 single-chip microcomputer as the master controller of an electronic stopwatch, the four LED displays. 2) after the power or RESET display 000.0. 3) When pressing the START button, the stopwatch as the use, display range is :000.0-999 .9 seconds, when pressing the STOP button, the stopwatch to stop running, and to retain the location of the stop show the same time.