cabbers
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B+-lose abilty to power via USB ports?

Sun Jul 27, 2014 5:01 pm

Hi
Got a new B+ but it looks like I cannot power via any of the USB ports, I now need to use the micro USB? Which I can live with, but would have been much better to have all the connectors (not HDMI as I use most of mine headless) from the same end.

thanks

cabs

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Re: B+-lose abilty to power via USB ports?

Sun Jul 27, 2014 5:07 pm

I think the lack of backpowering from USB was one of the B+ selling points...... :)
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Re: B+-lose abilty to power via USB ports?

Sun Jul 27, 2014 5:08 pm

Back powering has been removed AIUI, but it was never a feature anyway (it worked by accident) - the uUSB is the correct way of powering, or via the GPIO's.

We've removed the connectors from two side, three sides would have been very difficult to do.
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Re: B+-lose abilty to power via USB ports?

Sun Jul 27, 2014 5:10 pm

No backpowering (which was a shortcoming of the B) is now fixed (blocked).
You can now connect a hub that presents 5V to the PI, and at the same time power the PI the right way though the microUSB, no more bypassing or blowing up the fuse, or even blowing up a PSU.

P.S. powering through the 5V GPIO header is still possible, but bypasses the polyfuse!

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Re: B+-lose abilty to power via USB ports?

Sun Jul 27, 2014 5:15 pm

The shortcoming of the B was very useful sometimes. :roll: It breaks all the rules, but still useful, it only tended to work on the cheaper end of hubs because the better ones had circuitry preventing it.
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Re: B+-lose abilty to power via USB ports?

Sun Jul 27, 2014 5:18 pm

Cheers guys-I have over 20 Pi's, and I dont think any one has ever blown, or blown a PSU, whilst back-powering. Most of them are in remote locations, and the less space they take up, the better, so to have the microUSB hang out one side is a bit of a pain but that's progress for you! ;)
Now I know this, I'll be a bit more considered in my upgrade plans.

thanks

cabs

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Re: B+-lose abilty to power via USB ports?

Sun Jul 27, 2014 5:39 pm

On the plus side you're a lot less likely to need a hub at all with a B+. 4 sockets, better power management and very tolerant of hot plugging....
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Re: B+-lose abilty to power via USB ports?

Sun Jul 27, 2014 7:09 pm

Also, you probably cannot technically have backpowering, and hot-plug ability at the same time!

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Re: B+-lose abilty to power via USB ports?

Mon Jul 28, 2014 3:28 am

mahjongg wrote:Also, you probably cannot technically have backpowering, and hot-plug ability at the same time!
I did have hot-plugging while back-power on modified rev1.0 boards.
They had 500ma polyfuses at F2. Rev2.0 boards do not hot-plug while back-powered.

Shorting F2, on ver1.0, the hot-plugging did not work any longer.
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Re: B+-lose abilty to power via USB ports?

Mon Jul 28, 2014 4:25 am

I back fed for one project it was nice. I don't see it as a pro or con because in the end if I want to do it on a B+ soldering some jumpers is easy enough. A good rotary tool and a cheap soldering iron fixes a lot of problems.

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Re: B+-lose abilty to power via USB ports?

Mon Jul 28, 2014 8:02 am

There's still model B's out there if you need to back power the Foundation have said they will continue the "B" so that developers that need the consitency that was the "B" will still have that option.

It might have been better if they had named it the "C" but "B+" is their decision so we have to live with it. ;)
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Re: B+-lose abilty to power via USB ports?

Mon Jul 28, 2014 12:48 pm

If you really want to backpower then just solder a bit of wire from the 5V pin on the USB socket to the 5V pin on the GPIO header.

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Re: B+-lose abilty to power via USB ports?

Mon Jul 28, 2014 5:15 pm

Indeed. Going to be plenty of B's second hand I expect.
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Re: B+-lose abilty to power via USB ports?

Mon Jul 28, 2014 6:06 pm

Jim JKla wrote:There's still model B's out there if you need to back power the Foundation have said they will continue the "B" so that developers that need the consitency that was the "B" will still have that option.

It might have been better if they had named it the "C" but "B+" is their decision so we have to live with it. ;)
I agree, we have A and B .... C could have been the Compute module and the latest one could have been D :D

....so, who's going to start a thread about what the model E will be like?! :twisted:
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Re: B+-lose abilty to power via USB ports?

Mon Jul 28, 2014 6:35 pm

Don't bait the mods :D
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Re: B+-lose abilty to power via USB ports?

Mon Jul 28, 2014 6:54 pm

Cancelor wrote:....so, who's going to start a thread about what the model E will be like?! :twisted:
The Extraordinarily Enhanced Eben Edition? :D

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Re: B+-lose abilty to power via USB ports?

Mon Jul 28, 2014 6:59 pm

^^^ That's the one! ;)

Hummmm, mod baiting, it hasn't been outlawed yet?
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Jim JKla
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Re: B+-lose abilty to power via USB ports?

Mon Jul 28, 2014 7:09 pm

Mod baiting is a grey area.

I thought we were allready using the Eben Edition?

I will concede we are not on the Extrodinary Enhanced version yet. ;)
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Re: B+-lose abilty to power via USB ports?

Mon Jul 28, 2014 7:23 pm

Jim JKla wrote:It might have been better if they had named it the "C" but "B+" is their decision so we have to live with it. ;)
In case anyone is not aware, Models A, B, and B+ are references to the BBC Micro of the 1980s.

However, in that case the main difference between the B and B+64/128 was the amount of RAM. So arguably the 512MiB Raspberry Pi should already have been branded B+512, and the new board should be Master 512.

Luckily, Google at least seems to distinguish "Model B" and "Model B+" correctly.

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