在STM32上测量信号频率

Question

I need to measure the frequency of the input signal using stm32f407-Discovery and send it once per second. The frequency of the controller is 168 MHz. The maximum input frequency is 6 MHz. If I use EXTI, I can measure a maximum of 4 MHz. As the frequency increases, the values that change are more like noise. Although the estimated maximum interrupt frequency is approximately 13 MHz. What is the best way to solve this problem?

Answer 1

Use this signal as theclock signal for one of the timers.

Use another timer to trigger DMA transfer in the regular intervals. The CNT register change will be proportional to the frequency of the signal.

The rest is a very simple math.