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TMS320F28069: HRPWM using SYNCI - Can there be a "Dead Band"?

Part Number: TMS320F28069

Hello,

I'm using one of the  HRPWM signal outputs to generate a 'clock' - call that "X" MHz.  I am using the EPWMSYNCI signal which consists of a few signals that are ANDed together; and that SYNCI signal has a duty cycle of ~50%; and the longest period it could be deasserted is 500mS.  I was using the EPWM7A output; but I have moved this to EPWM2A and am using both of those outputs now; not that this affects anything regarding to what I think is like a 'dead band' for lack of a better description right now.

When the EPWMSYNCI signal is valid (the AND is '1') - the output of 'X'MHz is fine; but when the signal is invalid (the AND is '0') - I'm seeing a sort of 'drift' of the 'X'MHz signal.  The signal on EPWM2A (configured of course as HRPWM) - tends to drift somewhat.  I wanted to know if this is something expected or maybe I have a configuration bit not set correctly; but once the SYNCI signal is valid again; all is well.  I just didn't think this could drift a bit for the time the EPWMSYNCI wasn't valid.  In addition to looking at this on a scope; I have a calibrated frequency counter on the output of the EPWM2A signal and the output frequency does change slightly during the period EPWMSYNCI isn't valid.

I also don't currently require the SYNCO to be used; I suppose it's OK to not have this configured even though I'm using the SYNCI signal; but it would be nice to have TI confirm this.

Thanks,
John W.