基于单片机的频率计，能自动转换量程，以led只是不同的量程，以共阴数码管显示频率值，能区分是否需要小数点，附带pcb和仿真文件，已经做出过实物-Microcontroller-based frequency meter, automatic conversion range, led just different frequency range, common cathode digital tube display value, can distinguish whether the deci