CLK Clockspeed Calculations

Mark Hoover1

I am using a timer on the DM6467 to calculate some statistics reporting on multiple platforms. Each platform runs its respective DSP at a different clockspeed (I believe 600Mhz and 729Mhz). I am using the clock manager family of functions to capture the correct clock speed. in particular CLK_countspms() . I am noticing a drift in my statistics which I think I can attribute to the difference in clock speed. I believe that maybe the values used in the CLK functions could be incorrect for one of the platforms.

A few questions. Is it possible to look at the source of these functions to see what they're doing thus providing me a little more info? I believe I am running with BIOS version 5. Also, If I could find out how and where this clock speed value is defined I could simply change that for the correct platform. I have seen some mentioning in the .tcf file associated with the project, but I am unfamiliar with the fields used. Alternatively, is there another method I could use for clock speed calculations?

Thanks,
Mark

over 12 years ago

0 judahvang over 12 years ago

TI__Mastermind 32475 points

Mark,

I can check up on the source code question but I think under the licensing agreement for BIOS 5, we do not provide source code.

The Clock speed is defined under the GBL settings page when you open your .tcf file. You should be able to change it there.

I believe on the 64+/674/66 devices the simplest way to determine the clock speed is simply to look at the TSCL/TSCH counters. These run at the CPU speed. What I typically do is simply run the DSP for 10 seconds and see how much the value changes.

Judah

0 RandyP over 12 years ago in reply to judahvang

TI__Guru* 84110 points

Judah,

Is there a BIOS 5 variable that can be changed to reflect a different clock speed at run time? Is there a BIOS function call that can set this variable and change the timer PRD for the timer ticks?

Regards,
RandyP

0 judahvang over 12 years ago in reply to RandyP

TI__Mastermind 32475 points

RandyP,

Yes, if you change:

bios.GBL.CLKOUT

This should affect the period for the CLK.

Judah

0 RandyP over 12 years ago in reply to judahvang

TI__Guru* 84110 points

Judah,

Since bios.GBL.CLKOUT has to be set in the tcf file, that gets included into the build. Then that value is used to set the PRD for the timer ticks and to do the calculations mentioned above.

Is there a way to change this value at run time before the CLK manager has used it, or to change it in main() and restart/reset the CLK manager to use the new value?

RandyP

0 judahvang over 12 years ago in reply to RandyP

TI__Mastermind 32475 points

Randy,

I think you can try the following. Call GBL_setFrequency() then call CLK_reconfig().

Judah

0 Mark Hoover1 over 12 years ago in reply to judahvang

Prodigy 20 points

Thanks! I will mark this down in my notes for the future.

-Mark

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CLK Clockspeed Calculations