Shadow_7
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 4:09 am

Power? There seems to be no official power (mA) rating for the pi 2. Is it safe to assume that the 700mA minimum still applies? Do I need to upgrade my powered USB plug from 1A to 2A?

Various unofficial benchmarks suggest that the B (not B+) uses more power than the pi 2 under load. And all the pi's are < 1A. There seems to be nothing listed for power specific to the pi 2 on this site or any that you would BUY an pi 2 on.

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mikronauts
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 4:14 am

I should be doing some power testing tomorrow.

Do yourself a favour and get a good 2A power supply. You will be glad you did when you use a WiFi stick and more peripherals.
Shadow_7 wrote:Power? There seems to be no official power (mA) rating for the pi 2. Is it safe to assume that the 700mA minimum still applies? Do I need to upgrade my powered USB plug from 1A to 2A?

Various unofficial benchmarks suggest that the B (not B+) uses more power than the pi 2 under load. And all the pi's are < 1A. There seems to be nothing listed for power specific to the pi 2 on this site or any that you would BUY an pi 2 on.
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Advanced Robotics, I/O expansion and prototyping boards for the Raspberry Pi

W. H. Heydt
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 5:08 am

mikronauts wrote:I should be doing some power testing tomorrow.

Do yourself a favour and get a good 2A power supply. You will be glad you did when you use a WiFi stick and more peripherals.
Shadow_7 wrote:Power? There seems to be no official power (mA) rating for the pi 2. Is it safe to assume that the 700mA minimum still applies? Do I need to upgrade my powered USB plug from 1A to 2A?

Various unofficial benchmarks suggest that the B (not B+) uses more power than the pi 2 under load. And all the pi's are < 1A. There seems to be nothing listed for power specific to the pi 2 on this site or any that you would BUY an pi 2 on.
While I agree that having a good 2A supply is a great idea, unless you're using a lot of USB peripherals, or high powered ones, I'm not sure there is an actual need to go beyond 1A, so long as it's a *good* 1A unit.

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mikronauts
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 5:30 am

Pi + power hungry WiFi stick + ??? probably needs over 1A, and the price differential between 1A and 2A is minimal, so why take a chance?
W. H. Heydt wrote:
mikronauts wrote: While I agree that having a good 2A supply is a great idea, unless you're using a lot of USB peripherals, or high powered ones, I'm not sure there is an actual need to go beyond 1A, so long as it's a *good* 1A unit.
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dom
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 10:31 am

pico wrote:
dom wrote:

Code: Select all

#uncomment to overclock the arm. 700 MHz is the default.
arm_freq=840


Will this have any other unexpected consequences, apart from setting bit 24 on the Pi2 (as discussed)? Will the arm_freq of 840 simply be ignored by the Pi2, for example, and it will continue to run at the default 900MHz?
That will underclock the Pi2 a little to 840MHz.

Suppose Pi1 has serial 0x11111111 and Pi2 has serial 0x22222222 then you can do:

Code: Select all

arm_freq=950  # applies to any board
[0x11111111]
arm_freq=840  # applies only to board with serial 0x11111111
[0x22222222]
arm_freq=1000 # applies only to board with serial 0x22222222

Methanoid
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 11:18 am

OK overclocking on Pi2 seems confused with the warranty bit status. Is there somewhere a statement that says what settings we can use to overclock WITHOUT voiding warranty? I'd love to see what Pi2 will clock to but kind of like having a warranty for now ;)

Methanoid
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 11:19 am

mikronauts wrote:I should be doing some power testing tomorrow.

Do yourself a favour and get a good 2A power supply. You will be glad you did when you use a WiFi stick and more peripherals.
And what is a GOOD 2A PSU? Many people sell 2A but we can hardly test the PSU before buying so how do we know it provides a stable voltage and current.... Is there a list of tested ones?

mimi123
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 11:25 am

Methanoid wrote:OK overclocking on Pi2 seems confused with the warranty bit status. Is there somewhere a statement that says what settings we can use to overclock WITHOUT voiding warranty? I'd love to see what Pi2 will clock to but kind of like having a warranty for now ;)
You should just not use force_turbo=1 or use a modded blob with OTP writing disabled, so overvoltage 8 with warranty. :-) (but that thing is not shareable...)

skywatch
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 11:38 am

Just wondering if the GPIO pins on the pi 2 are the same as the B+?

I have SPI enabled (showing with lsmod) but no communication with an nrf24l01+. I have tried both sets of mosi,miso,sck pins and different RF modules, still no comms.

It works on a Pi1 modelB, and as the pi2 is fully compatible with pi1(?) I don't see whats wrong here?

S.

mimi123
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 11:39 am

skywatch wrote:Just wondering if the GPIO pins on the pi 2 are the same as the B+?

I have SPI enabled (showing with lsmod) but no communication with an nrf24l01+. I have tried both sets of mosi,miso,sck pins and different RF modules, still no comms.

It works on a Pi1 modelB, and as the pi2 is fully compatible with pi1(?) I don't see whats wrong here?

S.
The GPIO address base has changed. (only diff for VC4-based dev)

skywatch
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 11:51 am

Thanks, but how would that effect what I am doing and how do I get it to work with this new change (so not compatible with pi1 afterall it seems....).

S.

mimi123
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 11:54 am

skywatch wrote:Thanks, but how would that effect what I am doing and how do I get it to work with this new change (so not compatible with pi1 afterall it seems....).

S.
did you try lsmod?

skywatch
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 11:58 am

Yes, lsmod show SPI module loaded, that's what started to confuse me!

Also ls /dev/ shows SPI OK as well.


Thanks for the fast reply! :)

mimi123
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 12:15 pm

skywatch wrote:Yes, lsmod show SPI module loaded, that's what started to confuse me!

Also ls /dev/ shows SPI OK as well.


Thanks for the fast reply! :)
bizzare , the bare-metal driver works the same with a one line patch

skywatch
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 12:17 pm

Where can I find the 'one line patch'? Would it help in this situation do you think?

mimi123
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 12:18 pm

skywatch wrote:Where can I find the 'one line patch'? Would it help in this situation do you think?
It is my custom bare-metal driver.Will not work on Linux. I just had to modify BCM2835_PERI_BASE

Mausy5043
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 12:20 pm

joan wrote:My understanding is that the final six hex digits have the following interpretation.

Code: Select all

/proc/cpuinfo revision field

SRRR MMMM PPPP TTTT TTTT VVVV

S scheme (0=old, 1=new)
R RAM (0=256, 1=512, 2=1024)
M manufacturer (0='SONY',1='EGOMAN',2='EMBEST',3='UNKNOWN',4='EMBEST')
P processor (0=2835, 1=2836)
T type (0='A', 1='B', 2='A+', 3='B+', 4='Pi 2 B', 5='Alpha', 6='Compute Module')
V revision (0-15)

I find this highly unlikely.

I have 2 R-Pi B's.

Code: Select all

cat /proc/cpuinfo | grep Rev
returns 000e and 000f respectively.
That would make them both a model A.
Both my Pi B+'s return 0010 which would mean they are a model B.
Last edited by Mausy5043 on Sun Feb 08, 2015 1:05 pm, edited 1 time in total.

skywatch
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 12:22 pm

Ah, OK. I guess it's a waiting game then.

I have done all update, upgrade, dist-upgrade and rpi update firmware to 3.18.5 v7+ so will wait and see (could be a duff pi 2, but I hope not!).

Thanks.

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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 12:25 pm

skywatch wrote: rpi update firmware to 3.18.5 v7+
You're one notch behind the current.
Linux apollo 3.18.6-v7+ #749 SMP PREEMPT Sat Feb 7 18:15:06 GMT 2015 armv7l GNU/Linux
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skywatch
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 12:27 pm

Do you think that's the problem I have here?

I'll update again and see.

Thanks

skywatch
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 1:17 pm

3.18.6 - no SPI still it seems.

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DougieLawson
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 1:19 pm

skywatch wrote:3.18.6 - no SPI still it seems.
Add

Code: Select all

dtparam=spi=on
to /boot/config.txt and reboot SPI is working for me.
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skywatch
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 1:28 pm

Thanks, that is already in config.txt (probably added by raspi-config).

I can't test much more now, family time.

Maybe later.

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joan
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 1:36 pm

Mausy5043 wrote: ...
I have 2 R-Pi B's.

Code: Select all

cat /proc/cpuinfo | grep Rev
returns 000e and 000f respectively.
That would make them both a model A.
Both my Pi B+'s return 0010 which would mean they are a model B.
The new scheme is used by the Pi 2. Earlier models just have a (4 hex digit) revision number.

Mausy5043
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Re: The Raspberry Pi 2 Q&A thread

Sun Feb 08, 2015 1:43 pm

joan wrote:
Mausy5043 wrote: ...
I have 2 R-Pi B's.

Code: Select all

cat /proc/cpuinfo | grep Rev
returns 000e and 000f respectively.
That would make them both a model A.
Both my Pi B+'s return 0010 which would mean they are a model B.
The new scheme is used by the Pi 2. Earlier models just have a (4 hex digit) revision number.
Your earlier post suggested that it is possible to distiguish between the different hardware versions.
Now, I understand that one can really only distighuish between the Pi 2 on the one hand and [ A/A+/B/B+ ] on the other.

Might a firmware update (rpi-update) change that? Or is the revisionnumber hardcoded in the SoC?
Mausy5043 - NL

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