ontheair
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Raspi 2: Switching back to "original" 900 MHz clock speed

Fri Feb 06, 2015 8:46 am

Hello,

just a short (and maybe stupid) question about the clock speed of the Raspberry Pi 2:

By accident I switched the clock speed in raspi-config to 700 MHz. Now the Raspi is working at 700 MHz (under load) and at 600 MHz (while idle).

I would like to switch back to the "original" 900 MHz of the Raspi 2. But in raspi-config there is only an overclocking-option to 1000 MHz for Raspi 2. All the other clock options are meant to be for the Raspi 1.

So: How can I switch back to the "original" 900 MHz?

Thank you for any help!

Nr90
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Re: Raspi 2: Switching back to "original" 900 MHz clock spee

Fri Feb 06, 2015 10:00 am

You will have to manually set the clock speed value.
Have a look at http://elinux.org/RPiconfig#Overclocking
And how to edit: http://elinux.org/R-Pi_configuration_file

ontheair
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Re: Raspi 2: Switching back to "original" 900 MHz clock spee

Fri Feb 06, 2015 10:05 am

Thank you! So I will get a new raspbian, look for the default values for Raspi 2 and edit my file that way. Thanks!

Nr90
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Re: Raspi 2: Switching back to "original" 900 MHz clock spee

Fri Feb 06, 2015 10:06 am

That'll do the trick!

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Fidelius
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Re: Raspi 2: Switching back to "original" 900 MHz clock spee

Tue Feb 10, 2015 4:45 pm

Nr90 wrote:You will have to manually set the clock speed value.
Commenting-out or even deleting the four overclock lines in the boot/config.txt should do the same.
For example:

Code: Select all

#arm_freq=1000
#core_freq=500
#sdram_freq=500
#over_voltage=2

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Fidelius
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Re: Raspi 2: Switching back to "original" 900 MHz clock spee

Tue Feb 10, 2015 4:51 pm

raspi-config presents these options:

Code: Select all

Chose overclock preset                                                       
                                                                              
 None    700MHz ARM, 250MHz core, 400MHz SDRAM, 0 overvolt                     
 Modest  800MHz ARM, 250MHz core, 400MHz SDRAM, 0 overvolt                     
 Medium  900MHz ARM, 250MHz core, 450MHz SDRAM, 2 overvolt                     
 High    950MHz ARM, 250MHz core, 450MHz SDRAM, 6 overvolt                     
 Turbo  1000MHz ARM, 500MHz core, 600MHz SDRAM, 6 overvolt                    
 Pi2    1000MHz ARM, 500MHz core, 500MHz SDRAM, 2 overvolt                    
What MHz values do the two settings Core and SDRAM have on a Pi2 in standard mode i.e. non overlocked, compared to the quoted raspi-config's "Pi2" mode ? (The ARM7 is 900 MHz then, I think.)

mob-i-l
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Re: Raspi 2: Switching back to "original" 900 MHz clock spee

Thu Feb 12, 2015 9:39 am

I think raspi-config (RasPiConfig) should auto-detect if one has a pi1 or pi2 and present appropriate choices. One should be able to choose to set it back to original clocking also for pi2.
Raspberry Pi0&1A&1B2&1B+&2B&3B w/ Raspbian. Started w/ BASIC on ABC80&ZX81 then Forth, Z80… https://scratch.mit.edu/users/mobluse/ https://github.com/mobluse/ https://twitter.com/mobluse/ https://YouTube.com/MOBiL4u/

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Fidelius
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Re: Raspi 2: Switching back to "original" 900 MHz clock spee

Thu Feb 12, 2015 10:34 am

Just for the record, a moderator answered my above question in the The Raspberry Pi 2 Q&A thread :
dom wrote:
Fidelius wrote: What MHz values do the two settings Core and SDRAM have on a Pi2 in standard mode i.e. non overlocked, compared to raspi-config's "Pi2" mode ? (The ARM7 is 900 MHz in standard mode.)
By default arm_freq=900 core_freq=250 sdram_freq=450 on Pi2.
Thanks, Dom! So the Pi2's standard clocking is like the Pi1's Medium setting.

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B.Goode
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Re: Raspi 2: Switching back to "original" 900 MHz clock spee

Thu Feb 12, 2015 10:56 am

mob-i-l wrote:I think raspi-config (RasPiConfig) should auto-detect if one has a pi1 or pi2 and present appropriate choices. One should be able to choose to set it back to original clocking also for pi2.
The author/maintainer of raspi-config has made the code public via github. You could make the modifications yourself, or request that they be added to a future version: https://github.com/asb/raspi-config/issues

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DougieLawson
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Re: Raspi 2: Switching back to "original" 900 MHz clock spee

Thu Feb 12, 2015 5:50 pm

mob-i-l wrote:I think raspi-config (RasPiConfig) should auto-detect if one has a pi1 or pi2 and present appropriate choices. One should be able to choose to set it back to original clocking also for pi2.
It's a shell script. Read it, understand it and sharpen your coding pencil.
Hint: use the details from /proc/cmdline or /proc/cpuinfo to identify the board.
Note: Having anything remotely humorous in your signature is completely banned on this forum.

Any DMs sent on Twitter will be answered next month.

This is a doctor free zone.

mob-i-l
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Re: Raspi 2: Switching back to "original" 900 MHz clock spee

Wed Apr 29, 2015 6:12 pm

Fidelius wrote:Just for the record, a moderator answered my above question in the The Raspberry Pi 2 Q&A thread :
dom wrote:
Fidelius wrote: What MHz values do the two settings Core and SDRAM have on a Pi2 in standard mode i.e. non overlocked, compared to raspi-config's "Pi2" mode ? (The ARM7 is 900 MHz in standard mode.)
By default arm_freq=900 core_freq=250 sdram_freq=450 on Pi2.
Thanks, Dom! So the Pi2's standard clocking is like the Pi1's Medium setting.
But the medium setting is:
Medium 900MHz ARM, 250MHz core, 450MHz SDRAM, 2 overvolt

I.e. it has 2 overvolt. Does the default for Raspberry Pi 2 B also have 2 overvolt?
Raspberry Pi0&1A&1B2&1B+&2B&3B w/ Raspbian. Started w/ BASIC on ABC80&ZX81 then Forth, Z80… https://scratch.mit.edu/users/mobluse/ https://github.com/mobluse/ https://twitter.com/mobluse/ https://YouTube.com/MOBiL4u/

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kusti8
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Re: Raspi 2: Switching back to "original" 900 MHz clock spee

Wed Apr 29, 2015 7:37 pm

The pi2 has no over volt by default, so that wouldn't work. Just comment out all four lines in config.txt.
There are 10 types of people: those who understand binary and those who don't.

greenbag
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Re: Raspi 2: Switching back to "original" 900 MHz clock spee

Thu Sep 03, 2015 9:52 am

I came across a blog where they did stability tests with various different settings for the rpi2. The default is supposed to be arm=900, core=250, sdram=450, with no +V. Results.. stable but slow. But arm=900, core=450, sdram=450, with no +V.. results were OK.

http://linuxonflash.blogspot.ca/2015/02 ... mance.html

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