2008-11-11 08:07:38     CPU Frequency scaling with BF537

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2008-11-11 08:07:38     CPU Frequency scaling with BF537

Patrick Hotz (GERMANY)

Message: 65023   

 

Hi,

 

is it possible to make the CPU Frequency scaling working with the BF537 ?

 

I have try it with:

<*> CPU Frequency Scaling

  <*> Enable CPUfreq debugging

  <*> CPU frequency translation statistics

    < > CPU frequency translation statistics details

  <*> Default CPUFreq governor (performance)

  <*> "powersave" governor

 

but the error is:

no memory region specified for loadable section .initcall0.init

 

 

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2008-11-11 08:16:09     Re: CPU Frequency scaling with BF537

Mike Frysinger (UNITED STATES)

Message: 65025   

 

what software version are you using ?

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2008-11-11 08:19:11     Re: CPU Frequency scaling with BF537

Patrick Hotz (GERMANY)

Message: 65026   

 

I´m using uClinux 2007R1 and u-boot 1.1.3

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2008-11-11 08:37:40     Re: CPU Frequency scaling with BF537

Mike Frysinger (UNITED STATES)

Message: 65027   

 

cpufreq is not supported in those versions

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2008-11-17 09:04:49     Re: CPU Frequency scaling with BF537

Patrick Hotz (GERMANY)

Message: 65373   

 

Now I have successful running uCLinux2008R1.5 on my Board...

 

the frequency scaling is working with Performance (500MHz), Powersave (250MHz) and Ondemand.

Can i set the CPU-Frequency still lower (for example to 50MHz) ?

 

 

Thanks for your help

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2008-11-17 09:36:00     Re: CPU Frequency scaling with BF537

Michael Hennerich (GERMANY)

Message: 65374   

 

>Can i set the CPU-Frequency still lower (for example to 50MHz) ?

 

No - but you can suspend the system for more power savings

 

-Michael

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2008-11-17 09:49:15     Re: CPU Frequency scaling with BF537

Patrick Hotz (GERMANY)

Message: 65376   

 

Thats bad, I want to make a SIP-Phone which needs very low power.

 

Is there any changse to wake up the Blackfin if there is a SIP-Call?

 

 

 

Thanks,

Patrick

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2008-11-17 11:05:01     Re: CPU Frequency scaling with BF537

Michael Hennerich (GERMANY)

Message: 65381   

 

You can conserve further power –

Example your applications only requires 300MHz CCLK.

Than set CCLK = 300 MHz in u-boot. Cpu freq will then switch between 300 and 150 MHz.

 

Every System interrupt can wake the core out of standby.

For instance you can use a button, or Ethernet interrupt.

However there are lot’s of Ethernet interrupts so the core won’t get really into standby.

 

I think you need to have the core running, in order to determine whether there is incoming SIP call or not.

 

-Michael

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