Update pwm duty cycle at rising edge

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Update pwm duty cycle at rising edge

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christophosterl
Contributor I

Hello,

I have a problem with the settings of my pwm (K27). I'm updating the duty-cycle periodically. But even if the old and new duty cycle are the same, I see a jitter on my scope. Here, the "high" phase of the output signal is longer than it should be (e.g. 22us inset of 13us). So it seems that the couter is always started during a "high" phase. Is there any possibility to adopt the new duty cycle at a rising edge? I've tried several combinations of SWRSTCNT, SYNCMODE a.s.o, but did not find the correct combination.  

Do you have any ideas?

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Robin_Shen
NXP TechSupport
NXP TechSupport

Have you refer the methods in ftm example of MCUXpresso SDK_2.5.0_MK27FN2M0Axxx15?

ftm_simple_pwm.png
Try to find examples that are similar to what you need then test.

SDK_2.5.0_MK27FN2M0Axxx15 ftm.png

For more detail, please read the "44.5.11.4 MOD register synchronization".

44.5.11.6 C(n)V and C(n+1)V register synchronization.png

44.5.11.4 MOD register synchronization.png

Best Regards,

Robin

 

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