ds12887，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）-ds12887, using 51 single-chip expertise to design an adjustable time, with the whole point of the alarm clock. (Which use timers, interrupts, keypad, buzzer, digital control, or seri