TMS320F28033: When both EPWM3 and EPWM4 are synchronized with EPWM1(Master), EPWM3 can be phase-shifted by Alpha angle, but EPWM4 cannot be phase-shifted by Alpha angle.

Shaoxing Ke

Part Number: TMS320F28033

Hi Experts,

I am asking for my customer.

They are using HRPWM1A, HRPWM2A, HRPWM3A, HRPWM4A, both CTR = Up and down count mode, and HRPWM3A, HRPWM4A are synchronized with HRPWM1(Master). And they need change the TBPRD for frequency control, meanwhile the TBPHS of EPWM3 and EPWM4 need to be updated. You can see the below figure we have try, using the while loop to determine the conditions for the update of the CTR value, but it works for HRPWM3A sync to HRPWM1, not work for HRPWM4A sync for HRPWM1.

The TBPRD, TBPRDHR, CMPA, CMPAHR and TBPHS register given value in the ISR as below figure.

The HRPWM waveform output(When the frequency change from 100K to 90K, the red waveform (HRPWM3A) is correctly changed, but the blue waveform(HRPWM4A) not change.)：

So could you give me some suggestion/dir.? How to ensure that The TBPHS of HRPWM3 and HRPWM4 are updated at the same time? Thanks~

over 3 years ago

0 Shaoxing Ke over 3 years ago

TI__Expert 3590 points

Hi Experts,

The TBPRD, TBPRDHR, CMPA, CMPAHR and TBPHS register given value in the ISR, 50K, Timer0 trigger ISR. Any helpful suggestion?

0 Marlyn Rosales Castaneda20 over 3 years ago

TI__Mastermind 25390 points

Hi Shaoxing,

Shaoxing Ke said:
The HRPWM waveform output(When the frequency change from 100K to 90K, the red waveform (HRPWM3A) is correctly changed, but the blue waveform(HRPWM4A) not change.)：

Are EPWM3 and EPWM4 setup in the same configuration? It looks like the action qualifier events are different between the two EPWMs. Can you describe the other differences?

Best Regards,

Marlyn

0 Shaoxing Ke over 3 years ago in reply to Marlyn Rosales Castaneda20

TI__Expert 3590 points

Hi Marlyn,

Complementary waveforms of EPWM3A and EPWM4A. You can see the above figure.

0 Marlyn Rosales Castaneda20 over 3 years ago in reply to Shaoxing Ke

TI__Mastermind 25390 points

Hi Shaoxing,

Is the phase register (TBPHS) changed for EPWM4? Is it just the first cycle where you dont see a change in EPWM4 or does it never change? Would it be possible to see the configuration for EPWM3 and EPWM4?

In the flow diagram you showed for the ISR, why is there a while loop for EPWM1 and another for EPWM3?

Best Regards,

Marlyn

+1 Shaoxing Ke over 2 years ago in reply to Marlyn Rosales Castaneda20

TI__Expert 3590 points

Hi Marlyn,

Apologies for the delay, to ensure that all registers are loaded in the same cycle. Issue are solved, thanks for your help!

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TMS320F28033: When both EPWM3 and EPWM4 are synchronized with EPWM1(Master), EPWM3 can be phase-shifted by Alpha angle, but EPWM4 cannot be phase-shifted by Alpha angle.