Plastikdrucker
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Pi 400 - is network sharing over USB-C possible (gadget mode)

Tue Nov 10, 2020 3:04 pm

I tried the USB gadget mode with a raspberry pi zero some time ago and like it. I wonder if the Pi 400 also has this feature.

cleverca22
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Re: Pi 400 - is network sharing over USB-C possible (gadget mode)

Tue Nov 10, 2020 3:28 pm

it should work the same way, you just need to make sure there is enough amps on the usb port

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Disaster Incarnate
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Re: Pi 400 - is network sharing over USB-C possible (gadget mode)

Wed Nov 11, 2020 5:14 am

isnt the pi400 usb-c used to power it? is there a second way to provide power?

cleverca22
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Re: Pi 400 - is network sharing over USB-C possible (gadget mode)

Wed Nov 11, 2020 12:17 pm

Disaster Incarnate wrote:
Wed Nov 11, 2020 5:14 am
isnt the pi400 usb-c used to power it? is there a second way to provide power?
no secondary ways to power it, you might need a Y cable, or a powered usb hub to get enough power into that port

incognitum
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Re: Pi 400 - is network sharing over USB-C possible (gadget mode)

Wed Nov 11, 2020 12:22 pm

Haven't tried with the 400.
But the gadget mode works fine on a normal Pi 4. At least when connected to a normal desktop computer, where power is not an issue.

burtyb
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Re: Pi 400 - is network sharing over USB-C possible (gadget mode)

Sat Nov 14, 2020 2:14 am

Yes it works on the Pi 400.

To confirm what others have said you need to either make sure what you're plugging the USB-C into (for data and power) can supply at least a couple of amps or I'd advise using an adaptor or diy cable to split the power/data so you don't back feed one of the power supplies.

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mahjongg
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Re: Pi 400 - is network sharing over USB-C possible (gadget mode)

Sun Nov 15, 2020 3:42 pm

P.S. Powering the PI400 through the GPIO header is NOT going to work.

burtyb
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Re: Pi 400 - is network sharing over USB-C possible (gadget mode)

Sun Nov 15, 2020 9:50 pm

mahjongg wrote:
Sun Nov 15, 2020 3:42 pm
P.S. Powering the PI400 through the GPIO header is NOT going to work.
Hmm, putting what looks like a 1A power switch in the way is quite sneaky - I guess all will become clearer if/when we get the reduced schematics :).

CRImier
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Re: Pi 400 - is network sharing over USB-C possible (gadget mode)

Wed Nov 25, 2020 12:34 pm

Wait, there's some unexpected stuff going on with the Pi 400 GPIO header, and there isn't even a schematic for the changes?

That's exceptionally disappointing. There was no indication this change was coming, and such changes have potential to significantly hurt small sellers interested in making Pi 400-based products. In fact, here's one seller that's now, it seems, out a signficant sum of money because of this change. Earlier, you could rely on RPF to publish schematics that at least had the parts people were commonly interested in. Now, it's "oh BTW that feature you could always rely on for every other PI - that's not going to work".

It doesn't take more than an hour to make a cut-down schematic PDF, and it's been 20 days. I already have one product for Pi 400 released, and I was planning to make more. Now I don't know if I'll have to refund $200 worth of orders in 20 days' time and throw away $200 more in PCBs just because I want to deliver a Pi addon to help others make cool things, only to be surprised by changes that weren't communicated anywhere.
hackaday.io/CRImier
Current project - ZeroPhone

cleverca22
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Re: Pi 400 - is network sharing over USB-C possible (gadget mode)

Wed Nov 25, 2020 12:41 pm

ive cracked my pi400 open and had a look around the gpio, and i found what looks like a mosfet near the 5v pin, but ive not had a chance to fully investigate it

as for schematics, they usually come out a few months after the product they are for, if at all, and we never get an eta on them, its more of a surprise present that just shows up one day

edit:
jamesh wrote:
Thu Nov 05, 2020 2:48 pm
OK, so powering via GPIO is not possible on the pi400 due to stuff in there to stop nasty back powering issues happening.

It's also possible that the latest Pi4 will not do it either, but need to check.

In other news, there was a question about the USB power (VBUS) being cut when power is turned off, and yes, VBUS is off in that circumstance.
from over at viewtopic.php?p=1754886#p1754886

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