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SFO_MepDis_V5 Clarification

Tim Love
Expert 5340 points


Team,

In the F28335 HRPWM documentation SPRUG02, it stated specifically that the SFO_MepDis_V5() cannot be used on an ePWM channel while the HRPWM capabilities are enabled for that channel. However, in the SFO_V5 example in SPRC530 the following code was shown:

for(i=1;i<PWM_CH;i++)
{
 // Enable HRPWM logic for channel prior to calibration
 (*ePWM[i]).HRCNFG.bit.EDGMODE = 1;

 // returns "0" when cal. incomplete for channel
 while ( SFO_MepDis_V5(i) == SFO_INCOMPLETE );
}

As the above code shows, the HRPWM logic was enabled for each channel *BEFORE* SFO_MepDis_V5() was called. Appendix A of the document shows this same code without the HRPWM logic being enabled. Which method is correct, the example code or the documentation?

Regards,

Tim Love

  • TI__Intellectual 2690 points

    Tim,

    What the documentation means is that, the high-res. waveform will not be accurate while running the MepDis calibration - basically the high-resolution output on the ePWM pins is useless - this is why it states that while high-res capabilities are enabled, MepDis should not be used.

    BUT, in order for the high-resolution calibration logic to be enabled, the HRCNFG[EDGMODE] bits must be non-zero (otherwise the HRPWM logic will not be enabled for calibration).

     Hope that helps.

    -Chrissy

  • in reply to CChang
    TI__Expert 5340 points

    Chrissy,

    Thanks for the response. This makes sense. We may want to consider adding this clarification to the User's Guide so it is not confusing to customers.

    Regards,

    Tim Love