TMS320F28P650DH: the high-precision phase shift using HRPWM cannot be achieved

Steven Xu

Part Number: TMS320F28P650DH

Tool/software:

Hi, experts

I am currently facing a problem regarding the function of achieving high-precision phase shift using HRPWM.

In my project, PWM1 is used as the reference for the synchronous signal, and PWM5 and PWM11 are used for the phase shift operation. Both configure the Up Mode.

According to the manual reference, the following configuration of HRPWM has been carried out, and use the sfo library.

After Debug, I have observed that the values of the TRREM register is updating every PWM cycle from the CCS interface. but the PWM waveform on the oscilloscope show the high-precision phase shift has not come true.

Can you give me some advice?

6 months ago

0 Prarthan Bhatt 6 months ago

TI__Genius 13745 points

Hi,

Can you please refer to this thread : https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/1466820/tms320f28p650dk-hrpwm-of-phase-shift-only-works-to-mep-step-8-9-and-then-doesn-t-increase/5721928#5721928

I have also provided example projects for hr phase shift, please check and let me know if you have any further question

Thanks

0 Steven Xu 6 months ago in reply to Prarthan Bhatt

Prodigy 130 points

Thanks for your reply, After my confirmation, it has now been found that the auto conversion function of PWM11 cannot be used.

while When the MEP is set as a fixed value(256), the high precision of phase shift can be achieved, but the Edge of PWM will miss during the change of the phase shift value.

When I change PWM11 to PWM5, the auto conversion function can be used. and all goes well.

You can try to verify it.

0 Prarthan Bhatt 6 months ago in reply to Steven Xu

TI__Genius 13745 points

Steven,

For EPWM11 did you enable calibration with passing HRPWMCAL2_BASE ?

hrpwmcal1_base covers pwm1-8 so epwm11 wont work with that

Thanks

0 Steven Xu 6 months ago in reply to Prarthan Bhatt

Prodigy 130 points

Hi,

Yes, I noticed this REG before, but I don't know how to enable it, and it is not mentioned in the reference manual document

0 Prarthan Bhatt 6 months ago in reply to Steven Xu

TI__Genius 13745 points

Steven,

Check the HRPWM examples where we pass HRPWMCAL1_Base so instead we pass HRPWMCAL2_BASE for SFO function to calibrate

If both need to added then you pass both sequentially periodically

Thanks

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TMS320F28P650DH: the high-precision phase shift using HRPWM cannot be achieved