topic 回复： Regarding the measurement of the PWM output and duty cycle as well as frequency input of the FTM in Kinetis Microcontrollers

Regarding the measurement of the PWM output and duty cycle as well as frequency input of the FTM of

abyssnone — Fri, 26 Sep 2025 06:11:18 GMT

Hello!

I control one FTM to output PWM, and another FTM to measure the output PWM. When the frequency exceeds 10 kHz, the deviation between the measured frequency and duty cycle value and the actual value will increase as the input frequency increases. Moreover, why the PWM I output cannot be less than 25 Hz? Below 25 Hz, there is no output.

Please help me answer this question. Thank you very much!

Re: Regarding the measurement of the PWM output and duty cycle as well as frequency input of the FTM

gusarambula — Mon, 29 Sep 2025 16:25:10 GMT

Hello Abyssnone,

Would you please confirm which MCU you are using and if it's an NXP board or a Custom board? If you would please also include IDE and SDK version it would help us.

Regards,
Gustavo

回复： Regarding the measurement of the PWM output and duty cycle as well as frequency input of the FTM

abyssnone — Thu, 09 Oct 2025 02:02:51 GMT

Sorry, I'm not able to provide the entire code. I can only offer the relevant parts mentioned above.

回复： Regarding the measurement of the PWM output and duty cycle as well as frequency input of the FTM

Celeste_Liu — Fri, 10 Oct 2025 08:55:35 GMT

Hello @abyssnone ,

Could you tell me which MCU you are using? Specifically, I’m referring to its part number. Additionally, are you using a custom board or our FRDM board?
Which demo based on which SDK version are you using for testing?

BRs

Celeste

回复： Regarding the measurement of the PWM output and duty cycle as well as frequency input of the FTM

abyssnone — Sat, 11 Oct 2025 02:52:49 GMT

References the input_capture, dual_edge_capture, and simple_PWM engineering files. The chip is MKE13z.