说明：  基本要求：选择时钟芯片、在LED数码管切换显示日期和时间（LED显示格式为年4为月2位日2位），也可使用LCD实现（显示格式为××××年××月××日××时：××分：××秒）。使用多个按键实现设定、修改日期和时间，省电（关闭显示）等功能，键盘功能自行定义。 附加要求：实现闹钟功能（铃声自定）。
(Basic requirements: Select the clock chip in the LED digital tube display the date and time switch (LED display format for 4 years 2 months 2 day), but also realize the use of LCD (display format for the × × × × × × month × year × × × day when: × × points: × × seconds). Realize the use of multiple keys settings, modify the date and time saving (off display) and other functions, the keyboard function of self-definition. Additional requirement: the realization of an alarm clock function (custom ringtones).)