Author Topic: diy usb 2.0 hub  (Read 2256 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.

Offline 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?

Offline 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.
kilobyte = 1024 bytes (JEDEC standard)
kibibyte = 1000 bytes

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.

Offline Prime73

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Re: diy usb 2.0 hub
« Reply #14 on: July 06, 2014, 11:17:39 AM »
Resurrecting an old topic.
I've finally got some spare time on my hands and decided to finish this project and here is a quick update.
Attached is a schematic for the hub. I've build a prototype board and it seems to be working fine. I don't have fancy equipment to thoroughly test the design, however I've tested it using a couple wi-fi dongles and USB sticks/disks transferring different size files, etc and measuring resulting transfer rate. The results seems quite in line with other 2.0 hubs I have laying around.

All seems to be ok, however I can't get the LEDs working properly. For each downstream facing port, one LED (Green) is provided to indicate that the attached device of the corresponding port is enabled or not. All four ports are enabled (working) and I get both PORT1_LED and PORT3_LED working at the same time only if I plug something in USB3 port. If I plug something into USB1 port
both PORT1_LED and PORT3_LED do not light up. Similarly PORT2_LED and PORT4_LED both light up only when I plug something into USB4 and if I plug something into USB2 both PORT2_LED and PORT4_LED do not light up.

Last photo shows a microSD adapted plugged into USB4 port and both PORT2_LED and PORT4_LED light up. ( the amber LED at the very top is LED5 (hub status) )

I hope someone could help to figure this one. thanks in advance.



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