maemo.org - Talk

maemo.org - Talk (https://talk.maemo.org/index.php)
-   Nokia N900 (https://talk.maemo.org/forumdisplay.php?f=44)
-   -   N900 will not allow USB OTG! (https://talk.maemo.org/showthread.php?t=31921)

Mara 2009-09-23 20:27

Re: N900 will not allow USB OTG!
 
Personally I don't care much if the N900 does not have the USB OTG. In the past I did experiment with it when using N800. (You may remember the scripts and application entries I created to switch between the host and OTG modes?) Basically, it was just a one time interest and I rarely used it since then. (And the use was just experimenting... not that it was anything really useful.) When I changed to N810 I didn't even bother purchasing an adapter to make this work. I have had the N810 now about year and a half and I do not remember a single case where I was thinking "dang... I wish I had that adapter now..."

Not to say that for some this is a very important feature. But for 99% (?) of the folks it is not.

Also, you should not forget that the USB-OTG is not the same as full blown USB port that you see on PC's. OTG officially support 100mA current for the VBUS, where normal USB supports 500mA. Lots of devices need more than 100mA. In other words, many devices will not work with OTG port. (Like many memory card readers do not...) In that case you'd need external powered USB hub.

In my opinion the USB-OTG is more or less a niche. If it was supported and advertised feature on N900 box, guess how many unsatisfied customers there would be who say "my device doesn't work!", while they do not understand the difference between regular USB and USB-OTG?

thecursedfly 2009-09-23 21:40

Re: N900 will not allow USB OTG!
 
I understand and agree about the facts that many won't need it, and that if officially supported it would bring who knows how many complaints; thx also for the numbers. (I didn't know it was you who created the host mode script, nice work! ^^)

Personally I can't say it's something vital which I'll surely use everyday; it's a feature more that I knew previous models have, which I find cool and/because I imagine it can be very useful in many situations. Not to have that possibility lowers a bit the value for money I was earlier giving to the device, which made me post in search for a solution in this thread.
That doesn't mean I don't find it an exceptional device anymore; I could still find it interesting enough to get it.
But if it only had... ;)

Lets discuss back in search for a possible solution please... or wait for the device/some news... :p

Unless somebody has a prototype of the N900 and wants to share info or try dangerous (?) testmode scripts, both of which I don't really see happen, we can only wait for the N900 to be on the market.
Meanwhile, somebody can always have alternative ideas..

qole 2009-09-23 22:03

Re: N900 will not allow USB OTG!
 
Quote:

Originally Posted by thecursedfly (Post 332469)
... try dangerous (?) testmode scripts...

Sorry, where are these testmode scripts?

thecursedfly 2009-09-23 22:19

Re: N900 will not allow USB OTG!
 
Quote:

Originally Posted by qole (Post 332488)
Sorry, where are these testmode scripts?

I guess they still have to be coded by somebody capable of doing it.. (not pushing anybody! but maybe there's somebody capable and interested in doing it)

bocaJ 2009-09-23 23:03

Re: N900 will not allow USB OTG!
 
Anybody have experience puting together a bounty for this sort of thing? I'd chip in $20 to anyone who would develop a patch that gave the N900 full host mode or at least OTG capabilities without a hardware mod (aside from a special cable, perhaps).

BruceL 2009-09-23 23:05

Re: N900 will not allow USB OTG!
 
Quote:

Originally Posted by Mara (Post 331802)
Take a look at page 167 where they talk about emulating the VBUS signal... this may be more "clean" method of trying to get the controller into host mode?

Also, when I read the document it is apparent that the OMAP USB pins are not designed to be connected directly to the USB port. It needs some tranceiver chip between. I'm not sure if there are any other limitations on that tranceiver chip that prevent the host mode from working? (I don't think so, but you never know...)

So use an emulated VBUS to tell the chip to go into TESTMODE-Force_host?

I have only short bursts of time to work on things like this. Can someone read page 167-169 and figure out what this is saying and how to send a message on an emulated VBUS?

allnameswereout 2009-09-24 13:11

Re: N900 will not allow USB OTG!
 
Nobody interested in helping BruceL? The document is http://focus.ti.com/lit/ug/sprufd4b/sprufd4b.pdf

With USB OTG on microUSB the microUSB-B is always the EH, and the microUSB-A the OTG. The Nokia N900 has a microUSB-B connector; not microUSB-AB connector. Because of this it can only function as EH; not OTG. See http://en.wikipedia.org/wiki/USB_On-...TG_Micro_Plugs and http://en.wikipedia.org/wiki/Univers...-AB_Socket_OTG (the PDF linked to earlier mentions this as well). So you would either need to hack USB on both devices, or get a microUSB-AB plug on the Nokia N900. Or do you think grounding that one pin would work? Even so, you'd then have a microUSB-B to microUSB-B link.

Mara 2009-09-24 14:12

Re: N900 will not allow USB OTG!
 
Quote:

Originally Posted by allnameswereout (Post 332878)
Nobody interested in helping BruceL? The document is http://focus.ti.com/lit/ug/sprufd4b/sprufd4b.pdf

With USB OTG on microUSB the microUSB-B is always the EH, and the microUSB-A the OTG. The Nokia N900 has a microUSB-B connector; not microUSB-AB connector. Because of this it can only function as EH; not OTG. See http://en.wikipedia.org/wiki/USB_On-...TG_Micro_Plugs and http://en.wikipedia.org/wiki/Univers...-AB_Socket_OTG (the PDF linked to earlier mentions this as well). So you would either need to hack USB on both devices, or get a microUSB-AB plug on the Nokia N900. Or do you think grounding that one pin would work? Even so, you'd then have a microUSB-B to microUSB-B link.

I read a bit of those pages, and I don't really know how to "translate" it to simple commands. It seems the USB operation status is set by setting bits in a certain register, and it should do the trick. That register is also readable which should help on debugging/troubleshooting.

Also, the presence of Vbus normally tells if the device should be Host or Peripheral. But, this signal is not a direct input to USB controller. Tranceiver chip is the one to detect it which should output its status to the OMAP. After that it is purely a SW that does the rest. This is actually good news since it tells that there is no "hard wired" control to keep the USB controller in Peripheral mode. Just writing the correct bits to this USB register should make it into Host mode. :)

Sorry, I don't think I can figure out how to do this exactly, but for qwerty12 this should be a piece of cake... ;)

nilchak 2009-09-24 14:13

Re: N900 will not allow USB OTG!
 
Quote:

Originally Posted by qole (Post 332387)
Ok, so there are some of you out there who want USB host mode but don't have tablets at the moment.

That's puzzling to me!

If you don't currently have a tablet, what mobile device are you currently using that does have USB host mode? And what do you use it for?



I completely disagree with that statement.

Just assuming that I can pose for a moment that I don't have a Nokia Tablet (gave it to my wife :D), I have a Sharp Zaurus - which has USB Host mode.

And I want USB Host mode on the new device that I crave for - the N900.

And I use USB host mode for when I go on trips and take a lot of pictures and videos (large videos). WhenI get backt o the hotel room, I phug in my Camera and the portable HDD to the Zaurus - and copy all the media to the HDD as a backup and clean up the Camera media for the next day. In fact I do this for the whole group I go with - I am the chief Backup man.

Seriously now how do I do this with the N900 ?

timsamoff 2009-09-24 16:18

Re: N900 will not allow USB OTG!
 
Quote:

Originally Posted by nilchak (Post 332899)
Seriously now how do I do this with the N900 ?

I've been trying to follow this thread, but I often scratch my head at some of the use-cases that I'm hearing. In your case, removable media (SD, MMC, whatever) is so cheap now, why not take several with you and use the media itself as backup (i.e., for a 7-day trip, take 7 cards...)? And, if your camera uses microSD, why not just take the card from the camera and put it into the N900 to do the same thing? (If your camera uses regular SD, just slip a microSD card into an adapter.)

Yes, I know that there are valid reasons for USB Host mode, but in most cases, it just sounds like people want a way to (a) backup files, or (b) transfer/sync files. This can all be done via wifi, bluetooth, or USB (connected to a computer).

So... Maybe I'm missing something huge, but I just don't get the importance (for most normal users).

Tim


All times are GMT. The time now is 04:17.

vBulletin® Version 3.8.8