How to set RAMPSOURCE in F28035 comparator?

Jiakai Ye

Hi,

I need to use Ramp Generator in F28035 Comparator. Ramp Generator needs to synchronize with a PWM.

According to the description of ADC manual (SPRUGE5F), the PWMSYNC signal can be set at RAMPSOURCE of DACCTL Register. PWMSYNC signal can be one of PWMSYNC1, PWMSYNC2, PWMSYNC3 or PWMSYNC4.

Now my question is: where do PWMSYNC1-4 come from?

If I assume PWMSYNC1 is PWM1SYNCO from PWM1, how can I set PWM5-7 to associate with Ramp Generator?

thanks,

Jiakai

over 11 years ago

0 tlee over 11 years ago

TI__Guru 62975 points

Jiakai,

You can select the PWMSYNC source from HRPCTL[1] that is documented in the HRPWM reference manual. It should be documented in the EPWM manual as well, but it currently is not.

HRPCTL[1] = 0 will generate PWMSYNC when TCTR = PRD
HRPCTL[1] = 1 will generate PWMSYNC when TCTR = 0

PWMSYNCn comes from EPWMn

For RAMPSOURCE, you can assign the value of 4-6 to select between PWM5-7.

-Tommy

0 Jiakai Ye over 11 years ago in reply to tlee

Expert 1200 points

Thank you very much. I will check it.

Jiakai

0 Jiakai Ye over 11 years ago in reply to tlee

Expert 1200 points

Hi Tommy,

I checked HRPWM reference manual. HRCTL.PWMSYNCSEL decides the timing of PWMSYNC signal as you said.

Now I have another question, could you let me know If this bit is still working when the corresponding HRPWM disabled? (I don't need to use HRPWM in my program)

thanks,

Jiakai

0 tlee over 11 years ago in reply to Jiakai Ye

TI__Guru 62975 points

Jiakai,

Yes, this is a regular EPWM feature that wasn't documented fully.

-Tommy

C2000™︎ microcontrollers

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How to set RAMPSOURCE in F28035 comparator?