The Raspberry Pi Model B+ Q&A thread


 
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by RaTTuS » Mon Jul 14, 2014 2:04 pm
klricks wrote:Cost?
Newark / Element 14 has the B+ listed for 50.59 USD. The description says $35.00 but the higher price is shown on checkout cart.
Is this just a pre-order price that will go down to $35 in the near future after the rush?

the price is and always was $35 + local taxes and shipping...
now what is the reported price of the standard model B ....

see
http://www.newark.com/raspberry-pi-acce ... RR-Rasp-Pi
Last edited by RaTTuS on Mon Jul 14, 2014 2:53 pm, edited 2 times in total.
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by Totix92 » Mon Jul 14, 2014 2:07 pm
Code: Select all
max_usb_current = 1


This parameter is only valid for the new model B +? or even works in normal B models?
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by ShiftPlusOne » Mon Jul 14, 2014 2:08 pm
Totix92 wrote:
Code: Select all
max_usb_current = 1


This parameter is only valid for the new model B +? or even works in normal B models?

b+ only
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by solar3000 » Mon Jul 14, 2014 2:11 pm
1. I never notice a problem with audio.

2. Can I use the same software? Can I take a microSD->SD adapter card from the B and boot the B+? That is can I use the microSD card between the B and the B+ interchangeably? So if I boot the B with the card and then ten minutes take it out and put it in the B+. And then take it out and put it back in the B?

3. How can I use composite now that it's in the audio jack? And what's the pinout? Is it three conductor?

4. Will it rain tomorrow?
Last edited by solar3000 on Mon Jul 14, 2014 2:15 pm, edited 1 time in total.
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by Richard-TX » Mon Jul 14, 2014 2:15 pm
Richard-TX wrote:
In looking back at the history, I2c-0 went from the only bus available to "Thou shalt not use" in 2 revisions.


It appears that the i2c-0 connections are expected to be sacrificed to provide backward compatibility with peripherals that feature IDC connectors. Chop off those two pins and existing IDC connectors fit just fine.
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by ShiftPlusOne » Mon Jul 14, 2014 2:16 pm
solar3000 wrote:1. I never notice a problem with audio.

2. Can I use the same software? Can I take a microSD->SD adapter card from the B and boot the B+? That is can I use the microSD card between the B and the B+ interchangeably? So if I boot the B with the card and then ten minutes take it out and put it in the B+. And then take it out and put it back in the B?

3. How can I use composite now that it's in the audio jack? And what's the pinout? Is it three conductor?

1) That's good
2) Yes, as long as the firmware is up to date.
3) Something along these lines should work http://www.ebay.co.uk/itm/350843265424
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by solar3000 » Mon Jul 14, 2014 2:22 pm
ShiftPlusOne wrote:
solar3000 wrote:
---> 3) Something along these lines should work http://www.ebay.co.uk/itm/350843265424



what the hell is that? so if I plug regular phones in there will it short two of the conductors?
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by ShiftPlusOne » Mon Jul 14, 2014 2:23 pm
solar3000 wrote:
ShiftPlusOne wrote:
solar3000 wrote:
---> 3) Something along these lines should work http://www.ebay.co.uk/itm/350843265424



what the hell is that? so if I plug regular phones in there will it short two of the conductors?


No, why do you say that?
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by jamesh » Mon Jul 14, 2014 2:26 pm
Richard-TX wrote:
jdb wrote:
Richard-TX wrote:
There is always hope. But the way it sits now, we have lost something.


One of the I2C buses need to be "reserved" for use by Videocore to talk to the camera (and probably Display as well). Use of I2C0 on the ARM is not recommended as e.g. if you fire up Raspicam then Videocore will assume it has exclusive control of the interface, and start talking to it.

There is no electrical reason why you cannot connect random things to I2C-0, but unintended operation (including crashes/lockups) may occur if/when both Videocore and the ARM try to talk to the same piece of hardware at the same time.


The restriction regarding the camera and i2c-0 is well known to me. In my application a camera would be pointless so it does not matter.

In looking back at the history, I2c-0 went from the only bus available to "Thou shalt not use" in 2 revisions.


Well, that's progress for you. I2C0 was never meant to be used by anything but the camera anyway (as the 'not recommended for use' statement says). Is that actually causing you a problem? Why can't you use I2C1?

There is no protection to prevent the VC4 accessing the I2C0 at the same time as the ARM or vica versa. That's the inherent problem. The VC4 expects total dominion. BUT, if you are not using the camera or anything the VC4 may be expecting to be attached, you may be able to use it - with the caveats above. However, the VC does open the port on startup to see if there are any cameras attached (and always has done IIRC), so there may be some conflicts there.
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by ShiftPlusOne » Mon Jul 14, 2014 2:29 pm
jamesh wrote:However, the VC does open the port on startup to see if there are any cameras attached (and always has done IIRC), so there may be some conflicts there.


I think that only happens if you run raspivid/raspistill, vcgencmd get_camera or something else that checks for the cameras, not automatically. Even then, it only happens once and the result is saved for later use.
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by jamesh » Mon Jul 14, 2014 2:29 pm
solar3000 wrote:
ShiftPlusOne wrote:
solar3000 wrote:
---> 3) Something along these lines should work http://www.ebay.co.uk/itm/350843265424



what the hell is that? so if I plug regular phones in there will it short two of the conductors?


It's a Triple 3 x Phono COMPOSITE AV Video + RCA Audio to 4 pole 3.5mm Jack Adaptor

AFAIK, you should be able to use standard headphones.
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by jamesh » Mon Jul 14, 2014 2:30 pm
ShiftPlusOne wrote:
jamesh wrote:However, the VC does open the port on startup to see if there are any cameras attached (and always has done IIRC), so there may be some conflicts there.


I think that only happens if you run raspivid/raspistill, vcgencmd get_camera or something else that checks for the cameras, not automatically. Even then, it only happens once and the result is saved for later use.


Ah, OK, couldn't remember whether it was done at startup or not - it usually is to save startup time of the camera later, as it goes through the detection process.
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by redhawk » Mon Jul 14, 2014 2:37 pm
I don't like the changes to the video port I would have much preferred a 2 x 3.5mm headphone socket (one for audio one for video) rather than poorly standardised 4 pole connector.

So if I connect my headphones or speaker amplifier to the Pi (3 pole) is the video signal (1v p-p) protected from getting short circuited??

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by Richard-TX » Mon Jul 14, 2014 2:38 pm
jamesh wrote:Well, that's progress for you. I2C0 was never meant to be used by anything but the camera anyway (as the 'not recommended for use' statement says). Is that actually causing you a problem? Why can't you use I2C1?



I use i2c-1. As a matter of fact I use both buses. There are I2c devices out there that have a limited address space. (3 or fewer addr pins) so to be able to get a reasonable number of detectors per Pi, I need both buses.
Last edited by Richard-TX on Mon Jul 14, 2014 2:54 pm, edited 2 times in total.
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by jdb » Mon Jul 14, 2014 2:40 pm
redhawk wrote:I don't like the changes to the video port I would have much preferred a 2 x 3.5mm headphone socket (one for audio one for video) rather than poorly standardised 4 pole connector.

So if I connect my headphones or speaker amplifier to the Pi (3 pole) is the video signal (1v p-p) protected from getting short circuited??

Richard S.


It *is* standardised. It's an Apple standard, but still.

The video DAC does end up shorted to GND if you use a normal stereo jack, but it's a current source so doesn't care much about it.
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by dom » Mon Jul 14, 2014 2:47 pm
solar3000 wrote:2. Can I use the same software? Can I take a microSD->SD adapter card from the B and boot the B+? That is can I use the microSD card between the B and the B+ interchangeably? So if I boot the B with the card and then ten minutes take it out and put it in the B+. And then take it out and put it back in the B?

Yes, as long as image is up to date. Run:
Code: Select all
sudo apt-get update && sudo apt-get upgrade

on B, and it will work fine with a B+. Should be no issue when swapping back and forth.
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by Pi_Fanatic » Mon Jul 14, 2014 2:48 pm
The 4 pole pinout for the Pi Model B+ Audio / Video connector is not a standard. The pole position is as follows
From top to bottom:
Pin 1 Video
Pin 2 Ground
Pin 3 Right
Pin 4 Left
I have attached a helpful diagram. Not all off the shelf 4 pole audio / video cables will work. Most 3.5mm audio cables will work although the L/R might be switched on some.

av-pinouts.jpg
av-pinouts.jpg (51.55 KiB) Viewed 22939 times


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by jamesh » Mon Jul 14, 2014 2:53 pm
Richard-TX wrote:
jamesh wrote:Well, that's progress for you. I2C0 was never meant to be used by anything but the camera anyway (as the 'not recommended for use' statement says). Is that actually causing you a problem? Why can't you use I2C1?



I use both buses. There are I2c devices out there that have a limited address space. (3 addr pins) so to be able to get a reasonable number of detectors per Pi, I need both buses.


I don't think anything has really changed so I would expect you could still use both, as long as you are careful. So basically the same situation as before. But be aware that this is unsupported, and could change.
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by redhawk » Mon Jul 14, 2014 3:08 pm
How well does the Wolfson audio card sit on the Model B+ ??

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by RaTTuS » Mon Jul 14, 2014 3:11 pm
redhawk wrote:How well does the Wolfson audio card sit on the Model B+ ??

Richard S.

I don't think it can ,,,,
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by Richard-TX » Mon Jul 14, 2014 3:15 pm
jamesh wrote:
Richard-TX wrote:
jamesh wrote:Well, that's progress for you. I2C0 was never meant to be used by anything but the camera anyway (as the 'not recommended for use' statement says). Is that actually causing you a problem? Why can't you use I2C1?



I use both buses. There are I2c devices out there that have a limited address space. (3 addr pins) so to be able to get a reasonable number of detectors per Pi, I need both buses.


I don't think anything has really changed so I would expect you could still use both, as long as you are careful. So basically the same situation as before. But be aware that this is unsupported, and could change.


And that is precisely my point. Significantly change what is supported (an entire I2C bus) isn't an upgrade. Some would consider it a downgrade. Others might consider it a different device altogether. Sure, I could use I2C-0 for whatever I wanted, but the very second I do, I lose all official support. ("We told you not to use it.")

When peering into my crystal ball this morning, I see the demand for I2c multiplexers rising for hard core I2C implementers..
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by solar3000 » Mon Jul 14, 2014 3:15 pm
Pi_Fanatic wrote:The 4 pole pinout for the Pi Model B+ Audio / Video connector is not a standard. The pole position is as follows
From top to bottom:
Pin 1 Video
Pin 2 Ground
Pin 3 Right
Pin 4 Left
I have attached a helpful diagram. Not all off the shelf 4 pole audio / video cables will work. Most 3.5mm audio cables will work although the L/R might be switched on some.

av-pinouts.jpg


Pi_Fanatic



[thanks james/shiftplusone/dom also]

Yes helpful.

From this diagram, if I plug in a standard 3 conductor phone, wouldn't conductors 1 and 2 be shorted? On the new pie there should be four bent copper conductors [acting sort of like springs]. On a 3 conductor plug, the conductor closest to the barrel is longer than conductors 2 and 3.

Here:

Code: Select all
[_][_][_]{_}
VS
[____][_]{_}



And the jack on the pi I guess would be like this:
Code: Select all
/^ /^ /^ /^




I'm not saying the engineers didn't think of this. I'm trying to understand what it would mean for me.
Last edited by solar3000 on Mon Jul 14, 2014 3:19 pm, edited 1 time in total.
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by Richard-TX » Mon Jul 14, 2014 3:19 pm
RaTTuS wrote:
redhawk wrote:How well does the Wolfson audio card sit on the Model B+ ??

Richard S.

I don't think it can ,,,,


It doesn't. The Wolfson uses the P5 connector which is missing from the B+

Here is what is said about the card at Newark.

"Please be aware that the Wolfson Audio Card is only compatible with Raspberry Pis which feature the P5 pads, which can be found on Revision 2 Raspberry Pis onwards."

That statement will have to be revised.
Image
Note the P5 connections.
Last edited by Richard-TX on Mon Jul 14, 2014 3:36 pm, edited 1 time in total.
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by Richard-TX » Mon Jul 14, 2014 3:31 pm
A note to the Raspberry engineers.

If you guys are bored, why not come up with a SBC that uses the ARMv8-A processor running at 3 Ghz?

Food for thought.
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by mahjongg » Mon Jul 14, 2014 3:41 pm
Pi_Fanatic wrote:The 4 pole pinout for the Pi Model B+ Audio / Video connector is not a standard. The pole position is as follows
From top to bottom:
Pin 1 Video
Pin 2 Ground
Pin 3 Right
Pin 4 Left
I have attached a helpful diagram. Not all off the shelf 4 pole audio / video cables will work. Most 3.5mm audio cables will work although the L/R might be switched on some.

av-pinouts.jpg


Pi_Fanatic
Its the Ipod standard. It means you can buy cheap and plentiful iPod compatible cables / adapters, while at the same time you can plug in standard ear buds/headphones.

To me this sounds like the best and in the end cheapest solution.

There are also cables with different wiring orders in use, but as long as they have GND at the correct point, you can simply swap the RCA connectors to compensate.

As for using TWO 3.5 mm jacks, there simply isn't place for them!
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