本例子是采用定时计数器1实现精确定时1S，然后测量脉冲个数，从而得出频率-This example is used from time to time to achieve an accurate timing counter 1S, and then measuring the number of pulses so as to arrive at the frequency of

基于51单片机的数字频率计 c语言程序 能实现频率测试，用1602液晶显示-failed to translate

基于STM32的一个通用计算器频率计的程序-STM32 is based on a generic calculator frequency of procedures