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External PWM Syncronisation on falling edge with Piccolo

Stefan Fischer
Intellectual 680 points

Hi Alls ,

is it possible to trigger on the falling edge of the EPWMxSYNCI Signal instead of the rising Edge ?

I couldn't find any solution in the  EPWM-Reference Guide.

thx

Stefan Fischer

  • 0
    Genius 5170 points

    i actually couldn't find the rising edge requirement anyhere in documentation - I am sure I missed it ... however, the figures showing synchronization cases show rising edge starting synchronization and therefore I am assuming rising edge is required for synchronization. If  I understand the requirement correctly and you want a falling edge I guess in that case you will need an external glue logic. May be TI will advice. By the way, I am curious to know how many devices are you synchronizing and what is the application? Also, how much delay you can accomodate while synchronizing two or more devices?

  • 0 in reply to Arefeen
    Intellectual 680 points

    Hi,

    right now we inverted our sync signal with a hardware NOT logic because i also found no software option yet.

    We are syncronising 2 PWM Modules and the application is a kind of syncronous rectifier.

    the Delay from Sync to PWM Signal is 2*Sysclk

  • 0 in reply to Stefan Fischer
    Genius 5170 points

    May be I didn't undertand your setup... you are synchronizing two separate devices - correct? if yes then it is great that you are ensuring 2*Sysclk delay even for an external signal.

  • 0
    TI__Guru* 91990 points

    Stefan Fischer said:
    is it possible to trigger on the falling edge of the EPWMxSYNCI Signal instead of the rising Edge ?

    I couldn't find any solution in the  EPWM-Reference Guide.

    Unfortunately, you are correct, Stefan.  There is no way to invert the active state of this pin internal to the device.