实验为设置和读取RTC的时间。代码很简单，看一下就知道。只要注意读写RTC时钟寄存器前要先打开RTCEN位就行。-Experiment set-up and read the RTC time. Code is very simple to look at know. Attention to reading and writing as long as the RTC clock registers before RTCEN open spaces on the line.