要求以MCS-51系列单片机为核心设计一个多功电子表，具有电时钟和跑表功能。做时钟时在4位LED 显示器上显示分、秒，做跑表时显示范围000.0秒~999.9秒并具有跑表启动和跑表复位功能键。电子时钟的计时范围00分00秒59分-59秒，并在4位LED 显示器上显示；做跑表时显示范围000.0秒-999.9秒，当按下启动按钮跑表开始计时，按下停止按停止计时，当按下复位按钮跑表回零。-Request to MCS-51 series single-chip microcomputer as the core design of a multi-function electronic watches, clock and stopwatch with the power function. So the clock at the 4 LED display shows minutes and seconds, so when the display range stopwatch ~ 000.0 seconds and 999.9 seconds with a stopwatch to start and reset stopwatch function keys. The scope of the electronic time clock 00 minutes 00 seconds 59 minutes-59 seconds, and four LED displays show　to do display the scope of stopwatch-999.9 seconds 000.0 seconds, press the start button when the stopwatch timer, press the stop stop the clock, press the reset button when the stopwatch to zero.