i.MX6DQ PWM waveform is discontinuity when changes duty.

[satoshishimoda]

Hi community,

I have a question about i.MX6DQ PWM.

Our partner want to change the PWM duty with same frequency, but the waveform discontinuity is occurred when changes PWM duty as attached file.

To prevent this issue, what should we do?

If you need  more information, please tell me what you need.

Best Regards,

Satoshi Shimoda

[igorpadykov · Accepted solution]

Hi Satoshi,

PWM has FIFO to avoid this issue.

Probably customer utilized all FIFO samples.

The PWM will run at the last set duty-cycle setting if all the values of

the FIFO has been utilized, until the FIFO is reloaded.

Please read carefully Reference Manual PWM chapter.

Example usage of PWM one can look at SDK below

i.MX 6Series Platform SDK : Bare-metal SDK

Best regards

chip

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[satoshishimoda]

Hi chipexpert,

According to your reply, something was wrong when changing the duty of PWM?

Should I confirm the detail of procedure of changing the PWM duty?

Best Regards,

Satoshi Shimoda

[igorpadykov]

Hi Satoshi,

my reply was that FIFO should be always

filled (not empty) and check issue with SDK.

Best regards

chip

[satoshishimoda]

Hi chip,

Thank you for your reply.

But this issue was occurred on MCIMX6DL-SDP with jb4.2.2._1.1.0 also as attached image, so I think this is BSP issue.

Please see the how to reproduce as following.

1. Boot jb4.2.2._1.1.0 on MCIMX6DL-SDP.

2. Probe DISP0_CONTRAST signal by oscilloscope.

2. Settings -> Display -> Brighness, change brightness.

Best Regards,

Satoshi Shimoda

[igorpadykov]

Hi Satoshi

for Android issues please create new thread.

This thread was answered as hardware issue, not

associated with any operating system.

Software issues and hardware are considered separately.

Best regards

chip

[satoshishimoda]

Hi chipexpert,

OK, I will create a new thread about android pwm.

I appreciate you support.

Best Regards,

Satoshi Shimoda