AT89S51单片机实现闹钟功能，数码管动态扫描方式显示当前时间和带设定的定时时间，按键设置定时时间，蜂鸣器播放音乐提醒时间到-AT89S51 MCU alarm clock function, digital dynamic scan mode displays the current time and with a set of regular time, regular time set buttons, buzzer reminder time to play music