本程序可实现时钟两种工作方式（AM/PM）的切换。同时允许对时钟的时间进行调整和设置，且芯片自带备用电池，不会因断电而丢失数据-This program can be two ways of working to achieve clock (AM/PM) of the switch. While allowing time to adjust the clock and settings, and the chip comes with a spare battery, will not lose data due to power failure