时钟分频器原理与实现，计数跳变的频率和加减模式可实时变化，通过Nano实验板上的LCD显示器显示。计数频率、加减选择和初始化操作通过板上的拨动开关和Reset按钮实现。-Principle and Implementation clock divider, counting and addition and subtraction frequency hopping mode changes in real time, through the LCD display panel show Nan