定时器中断实验，分别设定时钟时间值和闹钟时间值，通过串口可以显示当前实时时钟时间值，当到达闹钟设定的时间后，会触发闹钟中断-Timer interrupt experiments, respectively, set the alarm clock time value and time value, through the serial port can display the current real-time clock time value, when the arrival alarm set time, it will trigger the alarm clock interrupts