TMS320F28P650DK: HRPWM and HRCAP

Irene Boben

Tool/software:

Hi Team,

I am using HRPWM and HRCAP in my code. The HRPWM output is captured in HRCAP and results are verified. The HRPWM example mentioned in the TRM is used.

i.e. TBCLK = 10 ns (100 MHz) , PWM frequency = 1.25 MHz (1/800 ns) and PWM duty cycle = 40.5%. The expected on time is 324ns. However, what I measure using HRCAP is 399ns. Is this tolerance of around 70-80ns expected?

Kind regards,

Irene

over 2 years ago

0 Ryan Ma over 2 years ago

TI__Mastermind 27736 points

Hi Irene,

Have you imported our example code that does this?

This tolerance does not seem as expected. Let me confirm with a team member and get back to you on this.

Best,

Ryan Ma

0 Ryan Ma over 2 years ago in reply to Ryan Ma

TI__Mastermind 27736 points

Hi Irene,

How are you connecting the ePWM outputs to the eCAP? Are you using inputxbar? Have you disabled the synchronizer on the input signal if you're using GPIO as input?

Are you running the HRCAP calibration continuously?

Best,

Ryan Ma

0 Irene Boben over 2 years ago in reply to Ryan Ma

Expert 1030 points

Hi Ryan Ma,

I am using input XBAR to read the ePWM outputs to eCAP. I am not running the HRCAP calibration continuously. Should I do that for better results?

Kind regards,

Irene

0 Ryan Ma over 2 years ago in reply to Irene Boben

TI__Mastermind 27736 points

Hi Irene,

Yes running the HRCAP calibration continuously in either background loop or ISR is required.

Best,

Ryan Ma

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TMS320F28P650DK: HRPWM and HRCAP