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TMS320F28335: I have a question about the PWM generation example from the C2000 academy materials.

Part Number: TMS320F28335

Hi, 

From TI's C2000 Academy materials, I found the following example:

[img1]

The example above seems to be based on the settings below.
AQCTL. CAU = SET;
AQCTL.PRD = CLEAR;

In the similar way, considering the case of PRD = 9 / Duty-cycle 20%, the actual PWM signal generation is thought to be as follows:

[img2]

If the PWM Action is changed to the following conditions, the actual generation of the PWM signal will change as follows. I wonder if there are any errors in my expectations.

AQCTL.ZERO = SET;
AQCTL.CAU = CLEAR;

[img3]

And I have an additional question. If the PWM signal is generated in the same way as [img3], the amount of calculation can be reduced compared to the way [img1 or img2].

Is there a any reason for the guidance given like [img1] in the C2000 academy example?

When creating an asymmetric PWM, is there a specific reason why the pulses need to be aligned to the right, so the C2000 academy example guides that way?

Thanks.

  • Hello,

    If the PWM Action is changed to the following conditions, the actual generation of the PWM signal will change as follows. I wonder if there are any errors in my expectations.

    Your expectations are correct.

    Is there a any reason for the guidance given like [img1] in the C2000 academy example?

    This is just meant to help explain how to achieve the desired duty cycle. There are multiple ways to think through it depending on the output desired.

    When creating an asymmetric PWM, is there a specific reason why the pulses need to be aligned to the right, so the C2000 academy example guides that way?

    This is just showing the "count" within the EPWM module as a visual representation. Its something that is happening within the device itself so you don't have the ability to configure this "right" alignment. 

    Best Regards,

    Marlyn

  • Thank you for your kind reply.