综合运用51单片机知识设计一个可以随意调节时间、带整点闹铃的时钟。（其中用到定时器、中断、按键、蜂鸣器、数码管或串口通信）-51 monolithic integrated circuits design integrated use knowledge to control at the time, the alarm clock on the hour. （ use of the timer, and buttons, the buzzer, digital or serial commun