frequency detection

[lwwl]

The main chip is k64p144, now want to detect the external input square wave frequency, Through the falling edge of the GPIO pin to capture external interrupt to achieve. If the external square wave frequency is 500 khz, this way can be achieved? Can the system support the work? If not, what is the maximum input frequency for the system? Thank you!

[Robin_Shen · Accepted solution]

Hi l w,

I recommand you configure FTM module as Dual Edge Capture mode, please read the chapter '40.4.24.4 Period measurement' of K64P144M120SF5RM.

Note that the maximum frequency for the channel input signal to be detected correctly is Bus clock divided by 4, which is required to meet Nyquist criteria for signal sampling.

Best Regards,

Robin

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