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Original question:

TMS320F28035: Question about the synchronization of EPWM modules.

TMS320F28035: External synchronization of PWM

Ahmed Azad
Prodigy 10 points

Part Number: TMS320F28035

I am using a TMS320F28035 for the first time. I have an external PWM signal coming from a PLL. I want the microcontroller to output a PWM which is synchronized to that external PWM. Also, I would like to be able to add some phase-shift to this synchronized PWM as well. Is it possible to do it using this microcontroller? Thanks in advance!  

  • 0
    TI__Mastermind 42195 points

    Ahmed, 

    there is an External sync in available on this device, so If you can provide a separate syncin signal then: Yes.

    If you cannot provide a separate syncin signal then the answer depends on the frequency of your PWMs.

     

    • If the The Master PWM’s frequency is slower than or equal to other slaves then: Yes
    • If the master PWM is faster than other PWMs then: the application becomes much more complex, and because you wan phase shifting between these PWMs I suspect the answer is no.

    Explanation why:

    If your master is faster then the slower slaves will be re-sync'd before they have a chance to complete their entire period. This will cause the effective period of slave PWMs to shorten, while not changing the compare values which will also result in a skewed duty cycle.

     

    Regards,
    Cody