ePWM or GPIO

Hi Sajjad,

instead of ePWM can I use GPIOs to generate sin-triangle PWM?

Any particular reason you want to do so? Also do you've a reference waveform you wan tto generate using these peripherals?

Regards,

Gautam

Hi Gautam

Thanks a lot for your reply.

The thing is, I don't know how to generate sine wave by using CMPX registers to compare with the up-down count (triangular wave) signals.

And I have to put some delay at the zero crossing of the sine waves (after both half and full cycle; kind of a dead zone but only at the zero crossing) 

And if I use normal GPIO then I need to code for the sine wave and then according to the sequence I will code for high frequency triangular wave, finally compare them for getting desired PWM signals.

Maybe I don't know much about "ePWM", that's why I don't to how to use CAPX registers. Btw I don't want to use the look up sine table, instead using  exponential equation to generate the sine wave.  

Kind Regards

Rafin

Raffin, there's a ready made SINE wave generation library available here:

C:\ti\controlSUITE\libs\dsp\SGEN\v101

For this you'll have to download controlSuite. BTW which controller are you using?

Regards,

Gautam

Thanks a lot bro! You saved my life once again! 

Let me check them, I hope it will work. Thanks again. 

I might seek help again if I get any confusion.  

I'm using TMS320F28335. 

Kind Regards

Rafin

Thanks a lot bro! You saved my life once again!

You're Welcome! I'm here to help :)

BTW I'll be travelling today and will try to catch up with you by tomorrow.

Goodluck & Regards,

Gautam

Bro

Thanks for your help, now I have managed  to generate sine triangle PWM signals. 

But I have to put more dead time in between PWMA and PWMB which will be more than 50u sec, see the figure given below red marked area would be the dead time zone. I know ePWM has dead time scheme but that is for the complimentary switching pulses for per leg. But in my case I do not require that, instead I need dead time after every 180 degree.   

Therefore, could you please suggest me any way to do so.

Sincerely 

Rafin

Rafin, I didn't get what exactly you're looking for. Are you looking for a similar waveform as mentioned above?

Bro, 

Actually I have managed to generate the waveform as shown above, but I could not able to get the gaps/dead times marked as red.

Sincerely

Rafin