TMS320F28377S: eCAP Capture Flag (CF) doesn't clear

Donald Johnson

Part Number: TMS320F28377S

I am using Matlab/Simulink 2017a with TIC2000 support package to develop software for a custom design. I am using an eCAP to capture the high and low time of a PWM signal so I can calculate the duty cycle.

It is reading the high and low counts properly. However when the signal is at 0% or 100% duty cycle the counts freeze (as expected) however the Capture Flag (CF) output stays at 1 even though I expect it to go to zero since there should be no capture happening.

Any thoughts?

Thanks,

Don

over 7 years ago

0 Frank Ankapong over 7 years ago

TI__Mastermind 28275 points

Hi Don,

ECFLG stays set until it's cleared with ECCLR. Are you saying ECFLG stays set after being cleared without any new events?

0 Donald Johnson over 7 years ago in reply to Frank Ankapong

Prodigy 185 points

Frank,

I am using the Matlab/Simulink eCAP block to do the capture. Apparently this block does not use ECCLR to clear the ECFLG, or I am missing some part of the magic incantation to make this happen.

Does anyone from Mathworks have some insight?

Thanks,

Don

0 Frank Ankapong over 7 years ago in reply to Donald Johnson

TI__Mastermind 28275 points

Don,

I've forwarded your question to Mathworks. You should get a reply from them soon.

0 venkatesh chilapur over 7 years ago in reply to Frank Ankapong

Mastermind 6460 points

Hi Don,

We agree with you, the status flag is not cleared after we read it. Thus, it remains set from the first event that occurred and since we never clear it, we continue to report '1'.

We have notified this to appropriate team and as a workaround you can use the Memory Copy block as captured in the image below to clear the flag.

0 Frank Ankapong over 7 years ago in reply to Donald Johnson

TI__Mastermind 28275 points

Don,

Do you have anymore questions on this?

0 Donald Johnson over 7 years ago in reply to Frank Ankapong

Prodigy 185 points

I haven't had a chance to test this. I am using a different work-around that doesn't require the eCAP.

If/When I get a chance to test this I will post my results.

0 Frank Ankapong over 7 years ago in reply to Donald Johnson

TI__Mastermind 28275 points

Don,

Since we can't keep a thread opened indefinitely, I'll be marking this as resolved based on the response from MathWorks. If you find that to not be the case after testing it out, feel free to reject the answer and reply to this thread or create a new one if this one locks out due to inactivity.

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TMS320F28377S: eCAP Capture Flag (CF) doesn't clear