CCS/TMS320F28035: About the utility of HR capture module

Shi Pu

Part Number: TMS320F28035

Tool/software: Code Composer Studio

Hi, I'm using HR capture module in 28035. Due to my check, there's only 4 functions that I can use in the HR calibration library, LowPulseWidth; HighPulseWidth;PeriodWidthRise;PeriodWidthFall. However, I'm trying to capture and obtain the value from the moment the CPU generate the interrupt flag to the falling edge. Is there any approach that I can do it?

What I'm trying to do is like this:

I want to capture the time interval length between point A and point B with HR capture module in ps level.

Thank you in advance.

over 8 years ago

0 Cody Watkins over 8 years ago

TI__Mastermind 42195 points

Shi,

there are some trick you can do if you only want eCAP resolution, but I don't know if you can do this with the HRCAP. I will look into this.

Regards,
Cody

0 Shi Pu over 8 years ago in reply to Cody Watkins

Prodigy 70 points

Since I want it to be captured in ps level, I suppose eCAP module is not precise enough. Thank you very much, I'll wait for your further reply.

0 Cody Watkins over 8 years ago in reply to Shi Pu

TI__Mastermind 42195 points

Shi,
I don't think this can be done on chip, if you were trying to find the time between two external signal you could use some basic combinational logic to get the desired results.
One thing you could try is toggling a GPIO as soon as that flag is set, and combining that output with the PWM output through an "and" gate but that will have some latency, and may not serve your purpose.

Hope it helps,
Cody

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CCS/TMS320F28035: About the utility of HR capture module