jamesh
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Re: Micro USB for powering PI is no longer OK

Sun Mar 25, 2018 4:59 pm

This argument has been done to death so many times before.

And yet here we are again.

A few people think its abusing the connector and a bad idea, others get on fine with it

My own opinion is that is the best option, until USB-C becomes more prevalent.

Barrel connectors are a no-no from the start for reasons outlined above.
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BluPI2
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Re: Micro USB for powering PI is no longer OK

Sun Mar 25, 2018 5:21 pm

I see absolutely no reason to move away from micro-usb at this point. I have a 5v 3amp supply and a 5.25v 2.4amp supply and they're both more than enough to power a Raspberry Pi 3 B+. If they do decide to upgrade the connector on say the Raspberry Pi 4 then wouldn't a Usb Type-C connector make more sense? That seems to be what the mobile industry is moving towards.

W. H. Heydt
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Re: Micro USB for powering PI is no longer OK

Sun Mar 25, 2018 5:24 pm

BluPI2 wrote:
Sun Mar 25, 2018 5:21 pm
I see absolutely no reason to move away from micro-usb at this point. I have a 5v 3amp supply and a 5.25v 2.4amp supply and they're both more than enough to power a Raspberry Pi 3 B+. If they do decide to upgrade the connector on say the Raspberry Pi 4 then wouldn't a Usb Type-C connector make more sense? That seems to be what the mobile industry is moving towards.
Dr. Upton mentioned that as a possibility for a future Pi in one of his interviews at the Pi3B launch. If a change has to be made, it would be a logical one as it would neatly avoid the quagmire of multiple, competing barrel connector "standards" as well as being a cable type readily available (if rather pricey at present).

jamesh
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Re: Micro USB for powering PI is no longer OK

Sun Mar 25, 2018 6:47 pm

IIRC, from a discussion in the office recently, the USB-C socket is at least three times the price of the current one. This can make a big difference when you are talking of something as cheap as the Pi.

Prices are bound to come down though.
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Re: Micro USB for powering PI is no longer OK

Sun Mar 25, 2018 8:39 pm

jamesh wrote:
Sun Mar 25, 2018 6:47 pm
IIRC, from a discussion in the office recently, the USB-C socket is at least three times the price of the current one. This can make a big difference when you are talking of something as cheap as the Pi.

Prices are bound to come down though.
I'm not the slightest bit surprised. I recently had to get a USB-A to USB-C cable. Where a USB-A to USB-microB cable runs about $1, the USB-C version was $10.

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Imperf3kt
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Re: Micro USB for powering PI is no longer OK

Sun Mar 25, 2018 11:14 pm

W. H. Heydt wrote:
Sun Mar 25, 2018 8:39 pm
jamesh wrote:
Sun Mar 25, 2018 6:47 pm
IIRC, from a discussion in the office recently, the USB-C socket is at least three times the price of the current one. This can make a big difference when you are talking of something as cheap as the Pi.

Prices are bound to come down though.
I'm not the slightest bit surprised. I recently had to get a USB-A to USB-C cable. Where a USB-A to USB-microB cable runs about $1, the USB-C version was $10.
Where do you live and what quality cable do you get for $1?
Where I live, the absolute cheapest, crappiest USB-A to Micro USB-B cables start at around $6 and the decent quality cables are nearly $30
55:55:44:44:4C
52:4C:52:42:41

W. H. Heydt
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Re: Micro USB for powering PI is no longer OK

Sun Mar 25, 2018 11:32 pm

Imperf3kt wrote:
Sun Mar 25, 2018 11:14 pm
W. H. Heydt wrote:
Sun Mar 25, 2018 8:39 pm
jamesh wrote:
Sun Mar 25, 2018 6:47 pm
IIRC, from a discussion in the office recently, the USB-C socket is at least three times the price of the current one. This can make a big difference when you are talking of something as cheap as the Pi.

Prices are bound to come down though.
I'm not the slightest bit surprised. I recently had to get a USB-A to USB-C cable. Where a USB-A to USB-microB cable runs about $1, the USB-C version was $10.
Where do you live and what quality cable do you get for $1?
Where I live, the absolute cheapest, crappiest USB-A to Micro USB-B cables start at around $6 and the decent quality cables are nearly $30
I said "about $1". Here's a 3' cable with 24 Ga power for $1.23: https://www.monoprice.com/product?p_id=5458 Sometimes they're on sale for less.

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Imperf3kt
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Re: Micro USB for powering PI is no longer OK

Mon Mar 26, 2018 1:30 am

I'll take it!
Its still cheaper than thirty dollars
55:55:44:44:4C
52:4C:52:42:41

paulslocum
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Re: Micro USB for powering PI is no longer OK

Mon Mar 26, 2018 5:38 am

This is what I use, 20AWg power lines for $3 each at most (but you have to buy at least 3).

https://www.amazon.com/gp/product/B018IAXUAA

ejolson
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Re: Micro USB for powering PI is no longer OK

Mon Mar 26, 2018 5:56 am

tkaiser wrote:
Sun Mar 18, 2018 11:48 am
If even most experienced RPi users like Dougie Lawson suffer from this problem.
I think most people are happy to run at 600MHz if all they have is a substandard power supply. That's better than the Pi not working at all. I ran a 2B powered from a spare USB port on my old PC for a year that way. Amazingly, the USB port delivered enough power to run the Pi at 600MHz even when the PC was turned off. At the same time, it would be nice to have a couple pins like the ones on the GPIO but not bypassing the power protection circuitry where one could connect a proper power supply.

tkaiser
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Re: Micro USB for powering PI is no longer OK

Mon Mar 26, 2018 8:03 am

paulslocum wrote:
Mon Mar 26, 2018 5:38 am
This is what I use, 20AWg power lines for $3 each at most (but you have to buy at least 3).

https://www.amazon.com/gp/product/B018IAXUAA
Yeah, I ordered a bunch of those too. Only way to power those SBC I have that unfortunately use Micro USB for DC-IN. With average Micro USB cables and their 28 AWG power lines it's simply impossible to get any reliable operation.

Once USB-C is everywhere this problem will be mitigated. Cables are a bit more expensive though: https://www.amazon.com/dp/B018X3IM6Y/&psc=1

But even with those cables it looks like this:
Image

There's a reason new USB PD standard switches to 9V or even 20V for those modes where more than 2A are required. Since it's stupid to try this with 5V.

The Pi 3+ with the new 1.4GHz DVFS OPP (dynamic voltage frequency scaling) is able to suck up to 1770mA from a PSU just by running something NEON optimized on the CPU cores (cpuburn-a53):
Image

With a spec rated for 1.8A maximum that's a great recipe for even more underpowering hassles. Well done...

jamesh
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Re: Micro USB for powering PI is no longer OK

Mon Mar 26, 2018 8:39 am

tkaiser wrote:
Mon Mar 26, 2018 8:03 am
paulslocum wrote:
Mon Mar 26, 2018 5:38 am
This is what I use, 20AWg power lines for $3 each at most (but you have to buy at least 3).

https://www.amazon.com/gp/product/B018IAXUAA
Yeah, I ordered a bunch of those too. Only way to power those SBC I have that unfortunately use Micro USB for DC-IN. With average Micro USB cables and their 28 AWG power lines it's simply impossible to get any reliable operation.

Once USB-C is everywhere this problem will be mitigated. Cables are a bit more expensive though: https://www.amazon.com/dp/B018X3IM6Y/&psc=1

But even with those cables it looks like this:
Image

There's a reason new USB PD standard switches to 9V or even 20V for those modes where more than 2A are required. Since it's stupid to try this with 5V.

The Pi 3+ with the new 1.4GHz DVFS OPP (dynamic voltage frequency scaling) is able to suck up to 1770mA from a PSU just by running something NEON optimized on the CPU cores (cpuburn-a53):
Image

With a spec rated for 1.8A maximum that's a great recipe for even more underpowering hassles. Well done...
I think you have made your opinion about USB power well known. Probably best to give it a rest now. I'm getting fed up with dealing with the reports, which are often quite rude, and offend my sensibilities.
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tkaiser
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Re: Micro USB for powering PI is no longer OK

Mon Mar 26, 2018 9:51 am

BluPI2 wrote:
Sun Mar 25, 2018 5:21 pm
I have a 5v 3amp supply and a 5.25v 2.4amp supply and they're both more than enough to power a Raspberry Pi 3 B+.
Why/how should amperage ratings of 3A or 2.4A matter when we're talking about Micro USB?

https://uk.rs-online.com/web/c/connecto ... onnectors/

69 connectors and their amperage ratings (for 3 there was none):

Code: Select all

 500 mA:  2
1000 mA: 36
1800 mA: 27
3000 mA:  1
Is the receptacle on the Pi an 1.8A or 3A part? Same with your PSUs: is the connector able to feed more than 1.8A via those tiny contacts without catching fire?

USB PD specs defined a new Micro USB receptacle rated for 3A (but should then only be used with 12V or 20V when exceeding 2A for obvious reasons). Are your parts compliant to USB PD specs (only then safe to be operated above 1.8A)?

jamesh
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Re: Micro USB for powering PI is no longer OK

Mon Mar 26, 2018 10:17 am

OK, I've now had to deal with yet another report on this thread. It's wasting my time when I am actually investigating reported networking problems.

So closing as we have no intention of not using uUSB until the next major upgrade, so its really a waste of time discussing it unless anyone reports an actual, real, provable issue caused by the use of the uUSB connector.
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