topic MCXA CTIMER PWM real time frequency variation question in MCX Microcontrollers

MCXA CTIMER PWM real time frequency variation question

Gagan_cepl — Fri, 30 Jan 2026 07:16:29 GMT

Is it possible to vary CTIMER PWM frequency in real time over a wide range, for example from 1 Hz to 4 kHz, while the timer is running?

In our application, when the PWM period is updated continuously during runtime, the following behavior is observed:

For certain period values, the PWM output temporarily stops and no frequency is generated. After further updates, the output resumes normally.

This issue is not seen when the PWM frequency is fixed. It only occurs during live frequency changes.

Is this an expected limitation of CTIMER PWM mode, or is there a recommended method to safely update the PWM frequency in real time across such a wide range without output gaps?

Re: MCXA CTIMER PWM real time frequency variation question

Alice_Yang — Fri, 06 Feb 2026 08:42:34 GMT

Hello @Gagan_cepl

There is an SDK example named ctimer_pwm_interrupt_example, where an interrupt callback frequently updates the PWM duty cycle. You can first test this demo on your side.

Alice_Yang_0-1770367263110.png

Alice

Re: MCXA CTIMER PWM real time frequency variation question

Gagan_cepl — Mon, 16 Feb 2026 08:30:37 GMT

Hello @Alice_Yang,

The example demonstrates how to change the PWM duty cycle, not the frequency. While the PWM varies as expected, my application requires the frequency to be changed rapidly in order to control the stepper motor speed.