Clock_getTicks() granularity question

Benjamin Foote

Other Parts Discussed in Thread: CC2640

Hello everyone,

I'm attempting to profile some code on my custom CC2640 board using Clock_getTicks() and I'm having a problem where the granularity that is returned by Clock_getTicks() seems to be in increments of 30. I am using it to profile code over time, and even code that should be separated by no more than a few ticks always returns a difference of 30, or 60, or 90, etc.

In my appBLE.cfg I have the Clock.tickPeriod set to 1, so I should theoretically be able to get a resolution of individual ticks, right? Does anyone have any idea why this behavior is occurring, or how to remedy it?

If anyone needs to see my code or anything, I can post some excerpts.

Let me know, thanks guys!

-Ben

over 7 years ago

0 Benjamin Foote over 7 years ago

Intellectual 700 points

I figured it out...the Util Clock module is driven by the external 32kHz crystal, which means the finest resolution is going to be 30uS.

In other words, you can't use Clock_getTicks() to measure/profile anything shorter than that.

I was only able to find one other obscure post on this, so hopefully this helps someone else out.

-Ben

0 Fredrik K over 7 years ago in reply to Benjamin Foote

TI__Guru** 106705 points

Hi Benjamin,

Good to hear that you figured it out. Thanks for posting!

Cheers,
Fredrik

0 Kenneth Koch over 6 years ago in reply to Benjamin Foote

Intellectual 480 points

I ran into that. off by 30-31uS every 5 measurements + or -
ticktocks[i + 15] = Clock_getTicks();
ticktocks[i + 30] = Clock_getTicks() - ticktocks[i + 15];
Thank you.

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Clock_getTicks() granularity question