CCS/TMS320F28069: HRCAP synchronization to EPWM module

Luiz Ramelan

Prodigy 190 points

Part Number: TMS320F28069
Other Parts Discussed in Thread: C2000WARE

Tool/software: Code Composer Studio

Hi Champs,

I am trying to implement phase detection using HRCAP module and found several challenges.

Is there any synchronization on HRCAP like ECCTL2->SYNCI_EN on eCAP module? Because I can't find it on manual.

I am also trying HRCAP Capture HRPWM on C2000ware as well. It is said the output is in Q16 includes integer and fractional. However, on manual both HCCOUNTER and HCCAPCNTRISE0 didn't mention about the fractional part. where I can access the fractional part? or is it locked inside the library.

any help is much appreciated.

regards,

Luiz

over 6 years ago

0 Cody Watkins over 6 years ago

TI__Mastermind 42195 points

Luiz,

this peripheral cannot sync to other parts of the device like the eCAP.

The result is a 32bit value, since its called a Q16 the user is meant to assume that it is a 16 bit interger and a 16 bit fractional portion. After reading this wiki article perhaps it makes more sense to call it a Q16.16 value.

The firmware developer's package mentions the format is 16 interger and 16 fractional.

https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/171/F2806x_2D00_FRM_2D00_DEV_2D00_PKG_2D00_UG.pdf

Regards,

Cody

0 Luiz Ramelan over 6 years ago in reply to Cody Watkins

Prodigy 190 points

Hi Cody,

Thanks for the answer.

I see, I also found that both capture results, rise and fall, only measure pulse width not the absolute counter at rising or falling.

So, can I say that eCAP module is more flexible in a way but HR CAP has advantage on higher resolution.

Regarding Q16, I had tried the example code properly and can see the fractional result. So, the Q16 result is only available by using the library, right? and can not be accessed directly from register.

Best regards,

Luiz

0 Cody Watkins over 6 years ago in reply to Luiz Ramelan

TI__Mastermind 42195 points

Luiz,

Luiz Ramelan said:
Regarding Q16, I had tried the example code properly and can see the fractional result. So, the Q16 result is only available by using the library, right? and can not be accessed directly from register.

I don't believe we document this HRCAP for use without the library. I suspect if you did a bit of digging you could figure out how to use the result registers, but this is not directly supported.

Regards,
Cody

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CCS/TMS320F28069: HRCAP synchronization to EPWM module