TMS320F280049: The diff between ePWM happen after sync ?

Hidehiko Kaya

Intellectual 690 points

Part Number: TMS320F280049

Hi experts,

Could let us know if phase difference between ePWM5 and ePWM6 increase or not ?

When clock source of ePWM is same, that difference is fixed after ePWM sync.

"after ePWM sync" means below processor.

1) TBCTL2.bit.SYNCSELX = 1;

2) TBCTL2.bit.SYNCSELX = 0;

Because ePWM5 out a sync signal twice when EPWMxSYNCO = CMPC,

ePWM6 counter is unexpected count-up/down behavior when ePWM6 is up-down mode.

Therefore we need to output one-shot SYNCO signal with CMPC.

We have a question. After one-shot sync, a phase difference between ePWM5 and ePWM6 is fixed ?

We expect that it is fixed because a clock source of ePWM is same.

Best regards,

Hidehiko

over 2 years ago

0 Marlyn Rosales Castaneda20 over 2 years ago

TI__Mastermind 23320 points

Hi Hidehiko,

Hidehiko Kaya said:
After one-shot sync, a phase difference between ePWM5 and ePWM6 is fixed ?

Can you please explain what you mean by "is fixed". The value in TBPHS is the value that will get written to the time base counter (TBCTR) when a sync occurs. If this value remains the same then the phase shift applied to EPWM6 should remain the same.

Best Regards,

Marlyn

0 Hidehiko Kaya over 2 years ago in reply to Marlyn Rosales Castaneda20

Intellectual 690 points

Hi Marlyn,

I mean that "is fixed" is stable, and is "not decrease/ increase continuously".

For example, phase difference of ePWMxes in different DSPs are changing continuously

because clock sources are different.

And so we can sync them with EPWMxSYNCI and EWPMxSYNCO between DSP#B and DSP#B.

However in same DSP, phase difference of ePWMx is stable.

In other words, phase difference of ePWMxes is kept because they have a same clock sources.

Best regards,

Hidehiko

0 Marlyn Rosales Castaneda20 over 2 years ago in reply to Hidehiko Kaya

TI__Mastermind 23320 points

Hidehiko,

Hidehiko Kaya said:
After one-shot sync, a phase difference between ePWM5 and ePWM6 is fixed ?

Phase difference between EPWM 5 and EPWM 6 should remain the same as long as the TBPHS value remains the same.

Best Regards,

Marlyn

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TMS320F280049: The diff between ePWM happen after sync ?