USB 2.0 OTG on N810 - Page 6 - maemo.org

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pearl62	2007-11-15 , 06:50
Posts: 54 \| Thanked: 6 times \| Joined on Feb 2006	#51

This may have been mentioned already, but just to clarify...

USB OTG is intended for single device connection only. It can certainly work with a USB memory dongle, as long the Mass Storage Class drivers are implemented in the N810. For that matter, any other USB device should also work as long as there are drivers implemented (some examples are Communications Device Class and Human Interface Device Class).

It differs from USB Host in that it specifically does not support hubs, and thus multiple devices.

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twaelti	2007-11-15 , 08:36
Posts: 883 \| Thanked: 980 times \| Joined on Jul 2007 @ Bern, Switzerland	#52

Originally Posted by LurkerN

the N810 is likely the first device to offer host mode using said standard.

The new Nokia N82 (released yesterday, available "now") has it, too.

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	dormant	2007-11-15 , 10:54
	Posts: 332 \| Thanked: 76 times \| Joined on Oct 2007 @ St. Augustine, Trinidad and Tobago	#53

Originally Posted by LurkerN

The N810 uses Micro, not Mini-USB (see Wikipedia)
I googled a bit and cannot find anyone selling Micro-A cables or adapters. This may be because the Micro-USB standard is quite recent, and the N810 is likely the first device to offer host mode using said standard.

Hang on. I was talking about the n800 at the time, which DOES use mini-USB cables.

__________________

N900
N800
LD-3W
two magic OTG USB adapters
crossed fingers

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muki	2007-11-15 , 11:31
Posts: 178 \| Thanked: 40 times \| Joined on Aug 2007 @ UK	#54

Excuse the repetition from another thread: hubs are not supported, so I'm wondering if that means that devices combining multiple devices, like a kb combined with a mouse, won't work. Maybe also effects things like external hd that also has an integrated hub?

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fanoush	2007-11-15 , 11:54
Posts: 2,152 \| Thanked: 1,490 times \| Joined on Jan 2006 @ Czech Republic	#55

Originally Posted by muki

Excuse the repetition from another thread: hubs are not supported

So, umm, what about linking that thread at least once? I already read two same comments by you, none has link to thread you are talking about.

As for hubs and other unsuported devices this is feature of linux kernel and is enabled in Nokia kernel. There is a white list of allowed USB devices, everything other is not allowed.

Code:

CONFIG_USB_OTG_WHITELIST:

 If you say Y here, the "otg_whitelist.h" file will be used as a
 product whitelist, so USB peripherals not listed there will be
 rejected during enumeration.  This behavior is required by the
 USB OTG specification for all devices not on your product's
 "Targeted Peripherals List".

This can be turned off when compiling own kernel.

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Newbies click here before posting. Thanks.

If you really need to PM me with troubleshooting question please consider posting it to the forum instead. It is OK to PM me a link to such post then. Thank you.

Last edited by fanoush; 2007-11-15 at 12:09.

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muki	2007-11-15 , 12:10
Posts: 178 \| Thanked: 40 times \| Joined on Aug 2007 @ UK	#56

Sry for missing the link, here you go: <other thread here>

Thanks for the info re kernel option. I thought OTG specification/implementation might be partly hw specific, hence the question (please, don't bother pointing me to USB specs, already been through that pain a few years back). So assuming the white list is there for a reason what, if any, would be the impact of turning this option off?

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fanoush	2007-11-15 , 12:49
Posts: 2,152 \| Thanked: 1,490 times \| Joined on Jan 2006 @ Czech Republic	#57

Originally Posted by muki

Sry for missing the link, here you go: <other thread here>

Umm, yes that is the first thread where you are talking about yet another thread. I was (and others may be too) interested in the original thread where you got the info from.

Originally Posted by muki

So assuming the white list is there for a reason what, if any, would be the impact of turning this option off?

The reason is quoted in kernel description in my previous post. Impact is obviously that untested devices will be allowed :-)

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muki	2007-11-15 , 13:06
Posts: 178 \| Thanked: 40 times \| Joined on Aug 2007 @ UK	#58

Hmmm, seems like you are determined to give me a hard time

Originally Posted by fanoush

Umm, yes that is the first thread where you are talking about yet another thread. I was (and others may be too) interested in the original thread where you got the info from.

The current thread of course! Specifically post #51.

Originally Posted by fanoush

The reason is quoted in kernel description in my previous post. Impact is obviously that untested devices will be allowed :-)

Never mind, I will seek the information elsewhere.

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muki	2007-11-15 , 13:24
Posts: 178 \| Thanked: 40 times \| Joined on Aug 2007 @ UK	#59

This wikipedia page says:

The USB OTG standard defines only one-to-one connection. Unlike standard USB, USB OTG does not use hubs. Connecting a USB hub between two OTG devices will lead to losing all USB OTG capabilities, locking one device as the host and the other as the peripheral until the hub is disconnected.

I read this as meaning that a hub *can* be used *but* still only one device can be used at a time. Any USB OTG expert please chip in if I am wrong.

PS: I don't have time to trawl the USB specs. I suppose the average user will simply want to know if it is at all possible to connect multiple devices.

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LurkerN	2007-11-15 , 17:25
Posts: 53 \| Thanked: 7 times \| Joined on Nov 2007	#60

Originally Posted by dormant

Hang on. I was talking about the n800 at the time, which DOES use mini-USB cables.

Oooops..... sorry

I have tunnel vision on the N810, at least until it is in my needy hands.

Yes, those cables from Lindy are indeed what you need. For something more versatile, you may want to check out this Gold-X Cable Kit. It has detachable connectors to create any standard USB cable possible (except, of course, the new Micro-USB). A bit of hackery will still be required to create the proper host cable for the N800, but it should be easier due to the Gold-X cable's design.