Maximum frequency of timers in STM?

Question

STM

Can the 32-bit timer in STM32F4/F7 be clocked at 216MHz-400MHz quartz to measure the time of flight of light? Do these boards have hardware FFT (FFT)?

Answer 1

Some porridge!
The 32-bit timer is clocked from the internal bus APB1 or APB2. Look in the datasheet for a chart on your percentage - the max frequencies are indicated there. To measure the time of _something_ (including the time of flight of light) you can also use a wrist watch! The question of accuracy and resolution. If I'm not mistaken, the maximum frequency of these buses is 108 MHz (but maybe the timers can be clocked at 216). It turns out that the tick of the timer is 5 ns (1/216 MHz), i.e. light in one tick of the timer in the air will fly 1.4 meters. But I'm afraid that the GPIO will roughen up your fronts and may give you an error. Must watch!
What fees are you talking about?
I may be behind, but I have not seen hardware FFT in microprocessors and microprocessors. Unless it's a special mikruha.