时钟设计方案：时钟的走时、显示同上个小节相同，在其基础上，添加硬件调时和闹钟的功能。为了实现功能，增加了4个按键，分别为K1、K2、K3、K4。-The design of the clock case: clock away, the display above a small section of the same, on its basis, add the hardware transfer function of the time and alarm. In order to func