Assuming I can solve for power (externally powered hubs) is there any maximum number of supported USB devices that the pi can handle?

Large(ish) hubs 7-8 ports are relatively cheap and I am wondering if there is anything built in that would prevent me from using a relatively large number of USB devices with a single RasPi (think 10 or more.)

  • IIRC the USB system can theoretically address 256 devices. But the bigger question is what type of devices are you going to connect and what effect will they have on the Pi's performance. 10 cameras will likely bring the Pi to its knees. While 10 flash drives doing little reading and writing will likely be OK. – Steve Robillard Dec 9 '13 at 18:35
  • Android devices in debugging mode. I am hoping to be able to send ADB commands to the devices. – FoamyGuy Dec 9 '13 at 19:53

The maximum is 127 devices - including the hubs themselves.
Some hubs will actually have two USB hubs internally, so you would need to take that into account also.
Though I can't imagine you hooking up so many devices for that to be an issue.

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    Also, In the case of the Pi or a Arduino or a Beagleboard, all those hubs need to be externally powered USB hubs. +1 for pointing out that some hubs actually have two hub devices internally. :) – Borislav Sabev Dec 10 '13 at 8:01

The conculsion of the test described on http://www.yoctopuce.com/EN/article/how-many-usb-devices-can-you-connect is that Raspberry Pi 2 appears to work with 10 devices sending messages at 100 Hz and it is impossible to get 17 devices to work simultaneously, even when they send almost no data.

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    Welcome -- I've removed the final sentence because that makes this a question, which is not how a Q&A site works (please take the tour), although the rest of the post is a reasonable answer. If you have a question of your own, please use the Ask Question page, linked top right. – goldilocks Aug 8 '16 at 18:15
  • but what would be the reason that only 17 devices are suported? – Denis Jul 2 '19 at 7:13

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