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

KiberGus 2010-03-24 17:23

Re: N900 will not allow USB OTG!
 
Quote:

Originally Posted by zimon (Post 580480)
Is this device capable to be gateway to any kind of USB-device or just between mass storage USB-device and something else?

Say, can one connect USB DVB-T dongle through this, and it would work if N900 just had drivers?

No. /*This message must be more than 10 symbols. This comment fixes it.*/

impatient 2010-03-24 17:37

Re: N900 will not allow USB OTG!
 
Quote:

Originally Posted by v13 (Post 577850)
I've tested something similar and transferred files from a camera to N900 but this is the one that acts as USB host (in both ends).

This is what I used but I don't know if it is related to this thread.

Thats not the one I have as mine has a sd and cf card slot on it and a little B&W lcd screen but the technical descriptions sounds about right. I have used it with SD card to portable HDD and pendisk to portable HDD, I shall try it on the n900 and see if I can find a link to the manufacturer tonight. I remeber the description on the box and in the instructions told you nothing as to what its capabilities actually was, even in the maplin catalogue it was badly described, they just called it a card reader with transfer capabilities or something similar. I think had people known what it was, more would have bought it.

impatient 2010-03-24 17:40

Re: N900 will not allow USB OTG!
 
Quote:

Originally Posted by zimon (Post 580480)
Is this device capable to be gateway to any kind of USB-device or just between mass storage USB-device and something else?

Say, can one connect USB DVB-T dongle through this, and it would work if N900 just had drivers?

Mass storage mode only.

impatient 2010-03-24 17:44

Re: N900 will not allow USB OTG!
 
Quote:

Originally Posted by donaggio (Post 578755)
Yes, but with such a device you can copy image files from a camera to N900 (or the other way round), while with proper host mode support you could just attach a camera to the micro-USB port and browse your images from the device itself.

At least this is what I was hoping for when I started the MRAWViewer project, before knowing that N900 lacked USB host mode!

It seems pretty quick though, just to copy a whole SD card or whatever. You can browse it once its using up some of the many GB available on the N900, I am sure browsing/editing will be quicker as a result.
I still have my fingers crossed we can get USB OTG working though.

joerg_rw 2010-03-26 13:07

Re: N900 will not allow USB OTG!
 
Quote:

Originally Posted by impatient (Post 580665)
I still have my fingers crossed we can get USB OTG working though.

It seems quite clear we never will get true OTG, as the hw isn't capable to do the fancy negotiating involved in that (aiui), and we even got the wrong (B type instead of AB) receptacle. What we *might* get eventually is USB-hostmode, probably enabled manually via some widget or setting

jOERG

johnel 2010-03-26 13:19

Re: N900 will not allow USB OTG!
 
Quote:

Originally Posted by joerg_rw (Post 583165)
It seems quite clear we never will get true OTG, as the hw isn't capable to do the fancy negotiating involved in that (aiui). What we *might* get eventually is USB-hostmode, probably enabled manually via some widget or setting

jOERG

OK so hardware switching of OTG is out of the question.

Is it beyond the realms of writing a software interface that pretends the n900 is in "host" mode and then connect a device to the USB port?

You start the software then tell it what you are connecting (e.g. keyboard or camera), plug the device in, click the "connected" button on the widget and then process the received data accordingly?

This is obviously grossly simplified - I imagine custom kernel and USB modules would be needed but surely something like this is possible?

joerg_rw 2010-03-30 22:42

Re: N900 will not allow USB OTG!
 
While doing this http://people.openmoko.org/joerg/n900/ I was able to identify N1140 USB Battery Charger chip as bq24150a -> http://www.ti.com/lit/gpn/bq24150. In this datasheet it's stated:
""To support USB OTG device, bq24150/1 provides VBUS
(approximately 5.05 V) by boosting the battery voltage.""
:D

So if PMU GAIA really misses this charge pump capacitor, maybe that's because we actually don't need it, and it's been Nokia's idea to use bq24150 for this.

Edit:: Nota bene this perfectly solves the "perpetuum mobile" problem - switching battery charger to VBUS-supply mode implies N900 will not start to charge from own powersupply

cheers
jOERG


result: http://talk.maemo.org/showthread.php...339#post649339

McLightning 2010-04-01 19:24

Re: N900 will not allow USB OTG!
 
is it still not possible?
i mean usb host

pelago 2010-04-01 22:33

Re: N900 will not allow USB OTG!
 
You would hear if it was. It'd be pretty big news.

blue_led 2010-04-07 18:01

Re: N900 will not allow USB OTG!
 
N1140 ( bq24150a ) USB Battery Charger chip pin D4 ( OTG [ input ] ) is hardwired to D4280 ( ISP1707 ) pin F2 [ CHRG_DET ]
according to cips specifications, isp1707 signaling external power ( charger attached ) on vbus and BQ24150 receiving this signal will start boost vbus !!! when external power is applied ?!!

this is a MONUMENTAL stupidity ..... or a smart idea but having bad implementation . the signal should be negated . if is not power on vbus you ( bq chip ) can boost vbus :D this hardwired signal should act as a protection -> if power is applied, don't boost vbus by mistake.
a regular host device put power on vbus all the time like any computer so if exist power on vbus from external charger ( accessory charger adapter ) a device attached to n900 will use that, else BQ chip will put power on vbus .

host mode limitation is software based


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