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TMS320F280049: Sync and trigger of F280049 SDFM

Brian Wang0
Expert 5540 points

Part Number: TMS320F280049

Hi team,

Here is a short question about SDFM.

According to my understanding the sigma delta fillter is a 'slide-window' filter, which means we can get a new result everything time a data received.

Thus, I am assuming the result of SDFM will be refreshed on every data clock. If multiple SDFM is connected to a common clock, they will be sync naturally.

So, my question is why we still need to sync and trigger SDFM? Can it also work like ADC to only sample once after triggered?

Regards,

Brian

  • 0
    TI__Guru 55700 points

    Brian,

    You're right!

    SDFM is slide-window filter (or) moving average filter. SDFM doesn't output at every SD-Cx clock cycle. It updates every OSR x SD-Cx cycles.

    Theoretically you're right, if you have one SD-Cx source which works on all filter channels you have them synchronized already. We have SYNC feature to time when to read the SDFM filter result with respect to PWM cycle. SYNC feature is not just to synchronize all the filter modules within SDFM.

    You don't have a way to stop SDFM pumping data every OSR SD-Cx cycle unless you disable the filter. But, you can SDFM FIFO configure to interrupt you only when you want.

    Regards,

    Manoj