Author Topic: diy usb 2.0 hub  (Read 1151 times)

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Offline Prime73

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diy usb 2.0 hub
« on: October 01, 2013, 05:49:04 AM »
Hello there,

I'm working on an expansion board for RPi which I plan to connect directly on top of it and I want to add a USB hub with 4 ports to my board. I use rev. A RPi (rev B. has only 2 ports and i need at least 3). I'm thinking to desolder an existing USB and have inter-board connector to get USB signals from RPI to my board. What's I'm looking for is a simple to implement USB 2.0 hub chip. Found FE1.1S on eBay and it seems fairly straight forward to use ( here is a datasheet for those who is interested: https://dl.dropboxusercontent.com/u/2414406/FE1.1s%20Data%20Sheet%20%28Rev.%201.0%29.pdf )
My question basically is - are there any alternatives? the FE1.1s seems to be only available from Hong-Kong/China and it usually takes 3-4 weeks to get it. I was looking at digikey and can't find anything similar.

Another question are there any "pin header" connectors I can use to interconnect USB pins from RPi to my board. A standard 2.54mm pitch doesn't fit 'cause two middle USB connector pins are closer together then the rest.

thanks in advance

Offline kripton2035

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Re: diy usb 2.0 hub
« Reply #1 on: October 01, 2013, 05:57:14 AM »
texas instruments has usb hub chips available quickly as samples
http://www.ti.com/lsds/ti/interface/usb-hub-controller-products.page?paramCriteria=no

Offline Prime73

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Re: diy usb 2.0 hub
« Reply #2 on: October 01, 2013, 06:40:20 AM »
thanks. requested TUSB2046B samples. Seems like what I need.

Online Monkeh

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Re: diy usb 2.0 hub
« Reply #3 on: October 01, 2013, 06:51:50 AM »
Those are not USB 2.0 hub controllers.

Offline Prime73

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Re: diy usb 2.0 hub
« Reply #4 on: October 01, 2013, 07:26:28 AM »
http://www.ti.com/lit/ds/symlink/tusb2046b.pdf
On page 14 there is an example of 4 port bus power hub. Sure it's not as simple as FE1.1S and requires  a power distribution switch and transient suppressors. Am I reading it wrong?

Online Monkeh

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Re: diy usb 2.0 hub
« Reply #5 on: October 01, 2013, 07:27:50 AM »
http://www.ti.com/lit/ds/symlink/tusb2046b.pdf
On page 14 there is an example of 4 port bus power hub. Sure it's not as simple as FE1.1S and requires  a power distribution switch and transient suppressors. Am I reading it wrong?


It is not high-speed.

Offline Prime73

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Re: diy usb 2.0 hub
« Reply #6 on: October 01, 2013, 07:50:23 AM »
 :palm: my bad
I thought I saw hi-speed in there... :)

http://www.ti.com/lit/ds/symlink/tusb2046b.pdf
On page 14 there is an example of 4 port bus power hub. Sure it's not as simple as FE1.1S and requires  a power distribution switch and transient suppressors. Am I reading it wrong?


It is not high-speed.

Offline David_AVD

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Re: diy usb 2.0 hub
« Reply #7 on: October 01, 2013, 09:26:59 AM »
How about this one?

Offline amyk

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Offline David_AVD

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Re: diy usb 2.0 hub
« Reply #9 on: October 01, 2013, 04:20:58 PM »
How is that not a hub?  I've used it before.

Offline amyk

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Re: diy usb 2.0 hub
« Reply #10 on: October 01, 2013, 04:28:57 PM »
How is that not a hub?  I've used it before.
Oh, sorry. Digikey...
Quote
Interface PCI
...made me think that was a host hub controller for a PC.

Offline jorisbeurden

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Re: diy usb 2.0 hub
« Reply #11 on: October 01, 2013, 07:49:19 PM »
I recently designed an embedded USB hub with a USB2512B controller from SMSC (Microchip) and it works perfectly. If you want a four port hub you will need the USB2514B from them. The only downside of this chip is that comes in a QFN package. I found the ability to flip the D+ and D- pin really useful to get a nice PCB. You can find more information at:

http://www.smsc.com/Products/USB/USB_Hubs/Standalone_USB_Hubs/USB251xB

The PCB I designed is only a two layer PCB which is not a standard with USB 2.0 design but SMSC has a nice appication note that describes the procedure at:

http://www.smsc.com/Downloads/SMSC/Downloads_Public/Application_Notes/an1517.pdf

The traces I use are: 0.85 mm wide with a gap of 0.20 mm on a 1 mm PCB. The ground is continuous under the traces and the clearance from the traces to the ground on the same layer is 1 mm. I still want to find out if I can use a normal PCB thickness without getting ridiculously wide traces but I haven't found a way to validate my calculation for them. 

I hope this helps and if you need to know more, let me know.

Offline mojo-chan

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Re: diy usb 2.0 hub
« Reply #12 on: October 01, 2013, 11:49:06 PM »
Designing a USB 2.0 is not trivial and the ICs are hard to get in the UK. In the end I decided it was easier just to install a small hub in our equipment's enclosure.

Offline Prime73

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Re: diy usb 2.0 hub
« Reply #13 on: October 02, 2013, 03:27:07 AM »
thanks for the info. Ordered FE1.1S. We'll see how it goes. Will update on the result.


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