maemo.org - Talk - N900 will not allow USB OTG!

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- - N900 will not allow USB OTG! (https://talk.maemo.org/showthread.php?t=31921)

Re: N900 will not allow USB OTG!

Quote:

Originally Posted by TA-t3 (Post 335893)

Note that the N900 uses micro-USB, the Pandora mini-USB. The rules are different for the former and that's what causes this particular problem.

Not different - the latter is simply not allowed by the standard so it has no rules :) It's the same thing as with the N800's OTG, which isn't quite OTG certified either. USB OTG specifies "The USB On-The-Go standard introduces a new plug receptacle called Micro-AB. An OTG product must have a single Micro-AB receptacle and no other USB receptacles.". And this is just the connector, we haven't even started talking about the software/logic part of it which is also part of the certification process...

Re: N900 will not allow USB OTG!

Well yeah, some mini-usb combos were removed from the standard so in that sense it's not _now_ allowed by the standards..

As for powering a device via micro-USB: EU or someone forced the phone makers to agree on a common power charging standard. For some reason micro-USB was chosen as the plug to use. Well, anything is better than charging via an unreliable multi-connector, as most of them do, and presumably none of the others wanted to move to a "Nokia" connector, so micro-USB it is. Now, does that mean that because micro-USB is used as a power plug, _all_ USB handling has to go through it, with the limits the charging functionality causes? An additional mini-USB would, in this case, have been better. But that's not even in the standard anymore, according to e.g. the link I posted a couple of postings above (or even _allowed_, according to your quote.)

Of course the whole insane mess is only due to the USB consortium. OTG, host mode, etc. etc. --- none of that would be needed at all if the standard had been sane. Instead we're stuck with this rubbish.

Re: N900 will not allow USB OTG!

By the way: what exactly are the benefits of the OTG certification? What would the n900 miss if it wasn't otg certified, besides the logo?

/edit
ok, so the n900 couldn't be sold with any usb port if it wasn't certified, and anything besides micro-usb for charging isn't allowed anymore... so without the certified microusb the n900 would have been illegal or something?

Re: N900 will not allow USB OTG!

@Mandor,

The OMAP3430 does not support charging via the USB port, that's a function of the USB transceiver which I would speculate is the TWL4030.

Quote:

Originally Posted by Mandor (Post 335710)

@Frank :

Correct me if I am wrong but from what I understand (and again you should take that lightly) OMAP3430 does support charging through the USB port and does support USB OTG. So I really don't understand when I read Nokia had to sacrifice USB OTG in order to get USB charging. Both are there anyway, don't they ?

Frank

Re: N900 will not allow USB OTG!

The OMAP3 processor contains 3 USB controllers, an OTG, an EHCI (high speed only) and an OHCI controller (full and low speed). There are some USB related errata that limit USB implementations. See 3.1.3.

Quote:

Originally Posted by TA-t3 (Post 335872)

No, that's not correct. Both ports are USB2.0, but the fullsize port (the host port, USB A connector) is HS (High Speed) only, it cannot support the other two (lower) speeds. On the other hand it can provide 500mA.

The small-connector OTG port (USB mini-AB) is also USB2.0, but it can support all three speeds. It can also be configured to be host port. But this port cannot provide more than 100mA.

Edit: Found a link that describes it better than I can: http://pandorawiki.org/USB_reference

Frank

Re: N900 will not allow USB OTG!

Yep, and that is whey the Pandora and the Beagleboard both have the same USB setup. And the N900 could have too, if it wasn't for the one-port only rule (see post #374 above)

Re: N900 will not allow USB OTG!

Anyone want to compile these drivers and post the .ko files? The ehci and ohci stuff especially.

The hardware sounds very similar, although of course there's no guarantees of anything.

Re: N900 will not allow USB OTG!

Quote:

Originally Posted by attila77 (Post 335934)

Yes, but that is from that last update from may 2009. The Nokia N800 was made before that date. Or, do you mean there never was officially a thing as USB OTG using miniUSB connectors?

Anyway, from what we gathered, Igor is absolutely right that USB consortium is the one and only organisation we should be angry at, and devote our complaint at. Not Nokia.

If your device does not adhere USB standard, you are not allowed to call that feature USB. Those are simple trademark rules, and these are even important for open standards (like with Android's 'Java'). If Pandora does not adhere USB standard but calls the ports USB then they may be in shallow waters. Perhaps they can work around by calling it USB-compatible, but even that is strictly speaking incorrect.

[EDIT, without digging in the USB docs it is pretty clear what happened with Pandora on the bottom of wiki page:

Quote:

mini-A and mini-AB connectors have been removed from the present USB standard. This means that the above connectors may vanish from the market at some point (although there will probably be demand for them for some time). There are a lot of connectors available that were never standardized. It is recommended that you do not use them as they may lead to non-working connections. Stick to the cables and adapters mentioned above and look for a mention of "OTG" or "On The Go" and you should be on the safe side.

Then follow 3 links:

Quote:

USB 2.0 Standard (including present OTG spec)
Original OTG Specification defining mini-A and mini-AB and allowed connections
mini-A and mini-AB Deprecation Announcement

They do not link to the revision from may 2009.

The last link is from may 23 2007 and is of particular interest:

Quote:

Vendors of USB On-The-Go (OTG) products are directed to adopt the Micro-AB receptacle on all new OTG designs in lieu of the Mini-AB previously approved for this application. In addition, all Mini-A and Mini-AB connectors that are currently on the Integrators List will be removed.

and

Quote:

On-The-Go Supplement to the USB 2.0 Specification, Version 1.3 – Previous versions of the OTG specification contained protocol and mechanical definitions, in this new version the mechanical section is removed. The Mini-A and Mini-AB cables and connectors previously defined in the OTG Supplement no longer have a place in any USB current specification.

I don't know how this certification works though. Does a final product require a certification? Then final Pandora will not pass USB certification.[/EDIT]

Re: N900 will not allow USB OTG!

allnameswereout,

Thanks for digging through all those details. It's clear that the USB consortium is flat without any common sense. Maybe the Pandora wouldn't pass an USB certification, I don't know if there is one, but there are rules for what stickers you're allowed to use. Pandora has already, afaik, determined that they won't use the official sticker.

The Pandora has a full-size USB (host) connector plus a mini (OTG) connector, and this makes sense. And it's not the only one, my Beagleboard (bought just a few months ago) has exactly the same.

Re: N900 will not allow USB OTG!

I just received my Mobidapter but it seems that the microsd slot of the E51, even if positioned on the side of the device, is too deep, and the adapter can't reach its contacts:mad::mad::mad:

I'll have to find a solution for that :mad:
At present, they are 40 Eur thrown away.
Well, maybe I'll be able somewhat to attach a flat cable and use it with the N900 :confused: