TMS320F280040-Q1: How to reset PWM registers to power-on default or set all PWMs A&B low

Crane Shao

Intellectual 910 points

Part Number: TMS320F280040-Q1

Hello,

I need to set all PWM1 and PWM2 both A and B channels low after it is enabled.

One way is to see all PWM registers power-on default value. Is there any way to do that?

Another way is to force all pin low at all events. But below code seems not working (some are low but some not):

EPWM_setActionQualifierAction(myEPWM1_BASE, EPWM_AQ_OUTPUT_A, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_ZERO);
EPWM_setActionQualifierAction(myEPWM1_BASE, EPWM_AQ_OUTPUT_A, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_PERIOD);
EPWM_setActionQualifierAction(myEPWM1_BASE, EPWM_AQ_OUTPUT_A, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_UP_CMPA);
EPWM_setActionQualifierAction(myEPWM1_BASE, EPWM_AQ_OUTPUT_A, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_DOWN_CMPA);
EPWM_setActionQualifierAction(myEPWM1_BASE, EPWM_AQ_OUTPUT_A, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_UP_CMPB);
EPWM_setActionQualifierAction(myEPWM1_BASE, EPWM_AQ_OUTPUT_A, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_DOWN_CMPB);
EPWM_setActionQualifierAction(myEPWM2_BASE, EPWM_AQ_OUTPUT_A, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_ZERO);
EPWM_setActionQualifierAction(myEPWM2_BASE, EPWM_AQ_OUTPUT_A, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_PERIOD);
EPWM_setActionQualifierAction(myEPWM2_BASE, EPWM_AQ_OUTPUT_A, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_UP_CMPA);
EPWM_setActionQualifierAction(myEPWM2_BASE, EPWM_AQ_OUTPUT_A, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_DOWN_CMPA);
EPWM_setActionQualifierAction(myEPWM2_BASE, EPWM_AQ_OUTPUT_A, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_UP_CMPB);
EPWM_setActionQualifierAction(myEPWM2_BASE, EPWM_AQ_OUTPUT_A, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_DOWN_CMPB);
EPWM_setActionQualifierAction(myEPWM1_BASE, EPWM_AQ_OUTPUT_B, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_ZERO);
EPWM_setActionQualifierAction(myEPWM1_BASE, EPWM_AQ_OUTPUT_B, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_PERIOD);
EPWM_setActionQualifierAction(myEPWM1_BASE, EPWM_AQ_OUTPUT_B, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_UP_CMPA);
EPWM_setActionQualifierAction(myEPWM1_BASE, EPWM_AQ_OUTPUT_B, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_DOWN_CMPA);
EPWM_setActionQualifierAction(myEPWM1_BASE, EPWM_AQ_OUTPUT_B, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_UP_CMPB);
EPWM_setActionQualifierAction(myEPWM1_BASE, EPWM_AQ_OUTPUT_B, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_DOWN_CMPB);
EPWM_setActionQualifierAction(myEPWM2_BASE, EPWM_AQ_OUTPUT_B, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_ZERO);
EPWM_setActionQualifierAction(myEPWM2_BASE, EPWM_AQ_OUTPUT_B, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_PERIOD);
EPWM_setActionQualifierAction(myEPWM2_BASE, EPWM_AQ_OUTPUT_B, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_UP_CMPA);
EPWM_setActionQualifierAction(myEPWM2_BASE, EPWM_AQ_OUTPUT_B, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_DOWN_CMPA);
EPWM_setActionQualifierAction(myEPWM2_BASE, EPWM_AQ_OUTPUT_B, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_UP_CMPB);
EPWM_setActionQualifierAction(myEPWM2_BASE, EPWM_AQ_OUTPUT_B, EPWM_AQ_OUTPUT_LOW, EPWM_AQ_OUTPUT_ON_TIMEBASE_DOWN_CMPB);

How to achieve that?

Thanks!

Crane

over 2 years ago

0 Nima Eskandari over 2 years ago

TI__Guru 52040 points

If you want to force things low you should use the tripZone module. Do you have DeadBand or tripZone in your configuration?

0 Crane Shao over 2 years ago in reply to Nima Eskandari

Intellectual 910 points

Ok. I have dead band and don't have tripZone right now.

0 Nima Eskandari over 2 years ago in reply to Crane Shao

TI__Guru 52040 points

That's it! Deadband comes after the Action Qualifier hence it is forcing outputs HIGH. TZ (tripzone should be able to override it all).

0 Crane Shao over 2 years ago in reply to Nima Eskandari

Intellectual 910 points

Tried different configurations and seems not working.

Do you have any example about how to override it or explanation of how Trip Zone works. I am still confused by reading the relevant sections in Reference Guide and Developers' guide.

0 Nima Eskandari over 2 years ago in reply to Crane Shao

TI__Guru 52040 points

Really the only thing you should have to do is configure your actions for the TZA and TZB events, then FORCE The OST action.

0 Nima Eskandari over 2 years ago in reply to Nima Eskandari

TI__Guru 52040 points

To see the driverlib functions that point to these registers, refer to the section:

...

0 Nima Eskandari over 2 years ago in reply to Nima Eskandari

TI__Guru 52040 points

0 Crane Shao over 2 years ago in reply to Nima Eskandari

Intellectual 910 points

Yes, these are what I tried:

// SysCtl_disablePeripheral(SYSCTL_PERIPH_CLK_TBCLKSYNC);
/* reset PWM1 and PWM2 */
EPWM_setTripZoneAction(myEPWM1_BASE, EPWM_TZ_ACTION_EVENT_TZA, EPWM_TZ_ACTION_LOW);
EPWM_setTripZoneAction(myEPWM1_BASE, EPWM_TZ_ACTION_EVENT_TZB, EPWM_TZ_ACTION_LOW);
EPWM_enableTripZoneSignals(myEPWM1_BASE, EPWM_TZ_SIGNAL_OSHT1);
// EPWM_enableTripZoneSignals(myEPWM1_BASE, EPWM_TZ_SIGNAL_CBC1);
// EPWM_enableTripZoneSignals(myEPWM1_BASE, EPWM_TZ_SIGNAL_DCAEVT2);
// EPWM_enableTripZoneSignals(myEPWM1_BASE, EPWM_TZ_SIGNAL_DCBEVT2);
EPWM_setTripZoneAction(myEPWM2_BASE, EPWM_TZ_ACTION_EVENT_TZA, EPWM_TZ_ACTION_LOW);
EPWM_setTripZoneAction(myEPWM2_BASE, EPWM_TZ_ACTION_EVENT_TZB, EPWM_TZ_ACTION_LOW);
EPWM_enableTripZoneSignals(myEPWM2_BASE, EPWM_TZ_SIGNAL_OSHT1);
// EPWM_enableTripZoneSignals(myEPWM2_BASE, EPWM_TZ_SIGNAL_CBC1);
// EPWM_enableTripZoneSignals(myEPWM2_BASE, EPWM_TZ_SIGNAL_DCAEVT2);
// EPWM_enableTripZoneSignals(myEPWM2_BASE, EPWM_TZ_SIGNAL_DCBEVT2);
SysCtl_disablePeripheral(SYSCTL_PERIPH_CLK_TBCLKSYNC);

I tried to un-comment out some of those statements that are commented out, no one is working.

The result is almost same as just calling SysCtl_disablePeripheral(). The difference is just that the different one of PWM1 and PWM2 outputs high.

Do I miss anything?

0 Nima Eskandari over 2 years ago in reply to Crane Shao

TI__Guru 52040 points

I dont see you FORCING THE ONE SHOT trigger.

EPWM_forceTripZoneEvent

0 Crane Shao over 2 years ago in reply to Nima Eskandari

Intellectual 910 points

Ok I see the software-force event, but didn't find which function to use.

Now it works. The new question is later after that, how to cancel that event to have normal PWM output? In our application, we need to switch between normal PWM output and all PWM outputs low.

It seems writing 0 to TZFRC is ignored. How to clear OST bit then?

0 Crane Shao over 2 years ago in reply to Crane Shao

Intellectual 910 points

Since there seem no way to cancel the trigger, it is solved by changing the trip action from ACTION_LOW to ACTION_DISABLE. You think it is proper way to do that?

By the way, I observe one thing interesting. In epwm.h, there is TZSEL, but when I use find to search for it, it shows "string not found". Any idea on why?

0 Nima Eskandari over 2 years ago in reply to Crane Shao

TI__Guru 52040 points

Crane Shao said:
how to cancel that event to have normal PWM output?

So you clear the latch for OST to remove the condition. The way to do it is writing a 1 to TZCLR[OST] which is EPWM_clearTripZone flag function in the table above. They are both in the two images above. It follows that format for all of the registers/driverlib functions.

0 Crane Shao over 2 years ago in reply to Nima Eskandari

Intellectual 910 points

Nice. This way is better.

Thank you for your help!

Crane

C2000™︎ microcontrollers

C2000 microcontrollers forum

TMS320F280040-Q1: How to reset PWM registers to power-on default or set all PWMs A&B low