Re: Issue 19 in beagleboard: Plugging in a usb OTG cable will prevent Beagle from booting

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Syed Mohammed, Khasim

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Jun 23, 2008, 7:35:22 AM6/23/08
to codesite...@google.com, Dirk Behme, Steve Sakoman, discu...@beagleboard.org


On 6/21/08, codesite...@google.com <codesite...@google.com> wrote:
Issue 19: Plugging in a usb OTG cable will prevent Beagle from booting
http://code.google.com/p/beagleboard/issues/detail?id=19

Comment #1 by dirk.behme:
Update from IRC [1] discussion:

- Test uImage send privately by Khasim doesn't work

- Felipe's recent OTG patches don't change anything

- Symptoms:

kernel doesn't boot. hangs in usb code:
 
I have USB OTG working on Latest OMAP GIT, I just used default Config in kernel, my version of u-boot 1.3.3 and MLO.
 
Please test the attached images on your board and let me know if you still find the issue, if it is something to do with u-boot then lets debug that further.
 
Regards,
Khasim
u-boot.bin
uImage
MLO

Syed Mohammed, Khasim

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Jun 24, 2008, 3:11:27 AM6/24/08
to codesite...@google.com, Dirk Behme, Steve Sakoman, discu...@beagleboard.org
Hi all:
 
I have USB OTG working on Latest OMAP GIT, I just used default Config in kernel, my version of u-boot 1.3.3 and MLO.
 
Please test the attached images on your board and let me know if you still find the issue, if it is something to do with u-boot then lets debug that further.
 
 
(12:36:56 PM) khasim: all: Floating USB mini B to USB A cable works for me on Beagle
(12:37:18 PM) khasim: but Floating USB mini A to USB A doesn't boot completely
(12:38:20 PM) khasim: the reason is: We have OTG and ethernet gadget enabled, the USB stack is trying to send DHCP over this, as we have it floating we don't receive any responce.
(12:39:39 PM) khasim: If we disable ethernet gadget or select any other mode liek File-backed storage gadget then it boots fine for floating mini A cable as well
 
Regards,
Khasim

sakoman

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Jun 25, 2008, 12:13:53 AM6/25/08
to Beagle Board
Syed,

Unfortunately I wasn't able to duplicate your success. I did discover
that my board *will* boot if connected to a Cyberpower hub, but will
not boot when connected to an IOGear hub.

After further research I'm fairly certain that this is a hardware
issue: unlike the EVM, the beagle design does not include filter
capacitors on VBUS. If you probe VBUS when the USB OTG adapter cable
is connected you will see that it is not a clean 5V -- it has several
volts of AC noise. The Cyberpower hub has VBUS filtering -- as soon
as it is connected VBUS becomes a clean 5V signal. IOGear probably
doesn't filter VBUS, because the signal stays just as ugly as before
it was connected.

To test this theory I piggy-back soldered a 2.2UF ceramic capacitor to
D3. After this hardware mod my beagle works in all cases: naked
cable, IOGear hub, and Cyberpower hub.

I think the USB HW design should be given a closer look prior to
releasing the next rev. I believe it needs the addition of filter
caps on VBUS, and I also believe that it may be missing series
resistors on the DN and DP signals (same goes for USB host port).

Steve

Philip Balister

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Jun 25, 2008, 9:15:58 AM6/25/08
to beagl...@googlegroups.com
On Wed, Jun 25, 2008 at 12:13 AM, sakoman <sak...@gmail.com> wrote:
>
> I think the USB HW design should be given a closer look prior to
> releasing the next rev. I believe it needs the addition of filter
> caps on VBUS, and I also believe that it may be missing series
> resistors on the DN and DP signals (same goes for USB host port).

Can you post a photo of the mod? I'd like to try this.

Philip

Coley, Gerald

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Jun 25, 2008, 9:32:13 AM6/25/08
to beagl...@googlegroups.com
Is this under a DC powered mode or is the Beagle pulling power from the
hub?

Gerald


-----Original Message-----
From: beagl...@googlegroups.com [mailto:beagl...@googlegroups.com]
On Behalf Of sakoman
Sent: Tuesday, June 24, 2008 11:14 PM
To: Beagle Board
Subject: [beagleboard] Re: Issue 19 in beagleboard: Plugging in a usb
OTG cable will prevent Beagle from booting

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