BBB with USB hubs

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irclarke
 
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BBB with USB hubs

Post by irclarke »

Hiho,
Hope you've all recovered from having our Ozzie version of Dubya up there (we wished you'd sent him to Guantanamo!).
Anyhow, I'm playing around with my Black Bones (Rev A6a, A6a, B & C) and thought I'd try the HDMI+keyboard+mouse arrangement, instead of puttying in.
Plugged in my hub with mouse and keyboard attached and no dice. Mouse or keyboard in directly works just fine.
Did a bit of digging in the forum and saw a post about USB 2.0 hubs being an issue. Is it still an issue? Or do I need to go get a USB 3.0 hub?
Cheers,
Iain in Tasmania

irclarke
 
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Re: BBB with USB hubs

Post by irclarke »

An update. Just borrowed a mate's USB 3.0 hub and that is a no go too. Are there any drivers/packages I need to install? Running the lastest Debian Wheezy 7.1 distribution dated 2014.05.14.

irclarke
 
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Re: BBB with USB hubs

Post by irclarke »

SOLVED! USB 2.0 unpowered works.

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paulf8080
 
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Re: BBB with USB hubs

Post by paulf8080 »

irclarke wrote:SOLVED! USB 2.0 unpowered works.
It works for you, but I should point my powered USB hub works. I use a powered hub so I don't have to get a bigger supply for the Black when I plug in my WiFi dongle. The release diffs for BBB Rev C say the C upgraded to USB 2, not 3.

tintar
 
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Re: BBB with USB hubs

Post by tintar »

not exactly a derail (or, if it is, apologies and I should post a new thread) but I had this odd idea and wondering if the recursiveness would collapse the universe or confuse the board overly-much:

- attach a powered USB hub to the A port of the board
- usual suspects: kbd/mouse, flash drive, wifi, bluetooth - on the hub
- *also* use the same hub to send power to the mini-B port of the board

still have a couple days before the thing shows up in the mail, to ponder the idiocy of my thoughts. I mean, I don't think it would asplode, but it probably won't be super-happy about it... er, right?

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adafruit_support_mike
 
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Re: BBB with USB hubs

Post by adafruit_support_mike »

That falls in the 'technically legal, but don't' category.

The big problem would be the existence of a power/ground loop between the cable that takes power from the hub to the BBB and the one that takes signals from the BBB to the hub. Drawing that schematically would make it look like a couple of redundant 5v/GND connections that shouldn't make any difference.

In practice you get small voltage offsets around the loop. Even a few millivolts of offset between the GND levels could pump a lot of power through a set of connections that don't have any protection against that kind of thing. It would probably boil down to a race between the hub's power supply and the BBB's power management chip to see which one blew first.

tintar
 
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Re: BBB with USB hubs

Post by tintar »

adafruit_support_mike wrote:'technically legal, but don't'
MUCH LIKE.

thank you.

yeah I kinda figured the same. being a big fan of: YEAH. EXCEPT DON'T.

also ordered an AC adapter from adafruit and currently using it.

unpowered hub with rtl-sdr 820T, flash drive, and huawei modem, all are happy.

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paulf8080
 
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Re: BBB with USB hubs

Post by paulf8080 »

Will replacing the connector with a 3 port work(I only need 3 ports). The B in USB does mean BUS.

http://www.mouser.com/ProductDetail/CON ... L5oPxqg%3d

Image

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adafruit_support_mike
 
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Re: BBB with USB hubs

Post by adafruit_support_mike »

It does, but USB is complicated.

USB is officially called a 'tiered star topology', in which each physical wire makes a point-to-point connection between a device called a 'hub' and a child device which can either be another hub or a 'function'. The first hub, to which all other devices connect, is called the 'root hub'. You can have up to seven layers of hubs (including the root hub) and up to 127 total devices with connections that lead back to the root hub.

You can't have two 'function' devices that share the same pair of wires to a hub though. If a device provides two functions (a webcam and a microphone for instance), it has to have an internal hub that serves as a single connection point for the functions.

Long story short, you'd need one of these as well: http://www.mouser.com/ProductDetail/Mic ... 4jFrz74%3d

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paulf8080
 
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Re: BBB with USB hubs

Post by paulf8080 »

adafruit_support_mike wrote:It does, but USB is complicated.

USB is officially called a 'tiered star topology', in which each physical wire makes a point-to-point connection between a device called a 'hub' and a child device which can either be another hub or a 'function'. The first hub, to which all other devices connect, is called the 'root hub'. You can have up to seven layers of hubs (including the root hub) and up to 127 total devices with connections that lead back to the root hub.

You can't have two 'function' devices that share the same pair of wires to a hub though. If a device provides two functions (a webcam and a microphone for instance), it has to have an internal hub that serves as a single connection point for the functions.

Long story short, you'd need one of these as well: http://www.mouser.com/ProductDetail/Mic ... 4jFrz74%3d
The reason I asked was I took a class for people that had to test mother boards with the newly introduced USB ports. Way back then devices shared the same wire and that was why it was called a bus. Because of that I assumed that connector ports shared pins and I could just solder it in. I was way off because the connector actually has separate. pins for each port. I guess I should be more up to date. I wonder when they switched from a bus to point to point.

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adafruit_support_mike
 
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Re: BBB with USB hubs

Post by adafruit_support_mike »

Technical terms tend to drift once the marketing department gets ahold of them. 'Bus' means something like 'shared data path for master/slave devices" these days. If the devices can make peer-to-peer connections rather than master/slave connections, the same topology will be called a 'network'.

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paulf8080
 
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Re: BBB with USB hubs

Post by paulf8080 »

adafruit_support_mike wrote:Technical terms tend to drift once the marketing department gets ahold of them. 'Bus' means something like 'shared data path for master/slave devices" these days. If the devices can make peer-to-peer connections rather than master/slave connections, the same topology will be called a 'network'.
It is the spec committee which has marketers, I guess. The original spec used the terms master and slave to describe the one wire sharing where there is only one master driving the wire at a time. Anyway, looking at the connector drawing and your hub chip tells me I need an external hub.

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