USB OTG (USB host functionality) on Razr - Working!

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Karmarock

Senior Member
Dec 5, 2007
95
5
I'm assuming Razr support usb host functionality as the motorola multimedia dock has USB ports.

I connected a samsung micro usb male to usb A female cable to it with a USB key (checked with a pair of models), but couldn't reach its files.
The Razr couldn't see it.

Maybe I'm missing something as I'm new to android world, but USB host functionality right from the phone without too many adapters would be the first thing I would show to any Apple's slave to show what modern phone is expected to do.

Hope I wasn't wrong as USB host capability + Bluetooth 4.0 together with its fast response and good audio were the quite unique specs (at least on the same device) which lead me to invest on it!

Anyone found a solution to use a standard adaptor or are we tied to the motorola multimedia dock (or hopefully at least a smaller proprietary adaptor?)
Maybe something like the Xoom 'desktop hack' could be a solution or is there any simpler one? I don't know exactly if this hack gave also OTG functionality together with unblocking the desktop mode (couldn't understand from what I googled around).

[go directly to the post with the actual findings
http://xdaforums.com/showpost.php?p=20008351&postcount=31
I'll update this first post with a resume of the findings as soon as I'll have time to :)]
 
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tornado75

Senior Member
Feb 16, 2005
133
6
I have usb host cable from my old s2 ,i have tried but doesn't works any usb pendrive or usb mouse/keyboard. :(


Inviato dal mio XT910 usando Tapatalk
 

kholk

Retired Recognized Developer
May 20, 2007
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It's useless.
You need a powered USBHost cable, so you need to connect the 5V to an external battery or an external power supply, and TX/RX to the USB end of the device you are connecting to the phone.

Or, alternatvely, you need a powered USB Hub.


It won't just work. Motos don't give any output power from the USB.
 

fletch33

Senior Member
Jan 9, 2010
1,355
398
i have the proper nokia cable which works on the Xoom but it wil not work on the RAZR (i assume) until like the Xoom a custom kernel can be installed to access this feature.

dont see that coming anytime soon (least not Verizon RAZR)
 

kholk

Retired Recognized Developer
May 20, 2007
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Can't you all read what someone writes prior you?
USBOTG WORKS ONLY IF EXTERNALLY POWERED. HARDWARE LIMITATION.
 

Karmarock

Senior Member
Dec 5, 2007
95
5
Can't you all read what someone writes prior you?
USBOTG WORKS ONLY IF EXTERNALLY POWERED. HARDWARE LIMITATION.

If OTG functionality were just a matter of powering a device with an external source that would not be a big issue considering the avaiability of power reserve devices.
I think a step forward in understanding Razr's OTG capabilities will be given dismantling a multimedia docking station and playing with it as soon as it will be available.
 

kholk

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May 20, 2007
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@Karmarock

micro-usb-b.jpg

1 VCC Red +5 V
2 D− White Data −
3 D+ Green Data +
4 ID none Mode Identification
5 GND Black Ground

LapDock:
+5V and GND connected directly to the battery of the LapDock, TX+RX connected to the integrated USB HUB.

Docking Station:
+5V and GND connected directly to external power (5V AC), TX+RX connected to the integrated USB HUB.

Oh, in BOTH, for enabling the Host Mode, pins 4 and 5 are shortcircuited, exactly as the USB OTG specifications.
 
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Karmarock

Senior Member
Dec 5, 2007
95
5
Dismounted a micro usb male to USB female cable, to my surprise found it with connection 4 free.
Hence made the 4-5 bridge and checked again.
Yet no usb host connectivity with an external powered 2.5 HD.
The HD happened to charge the Razr.
Hence modified the cable disconnecting the +5V.
Now I should have an OTG cable with an external powered devices.
As soon as I'll find back my USB Y cable I'll check with it and some external devices to see if any of them is recognized right out of the box.

Yet I suspect that, like the Razr Upon USB connection let you choose between some differents kind of connections, maybe some settings has to trigger host mode.
Any idea?
 
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Karmarock

Senior Member
Dec 5, 2007
95
5
You've done something wrong, mine works fine in USBHost Mode.

What an incredible news! :eek:
There are quite a bunch of posts around about Razr USB host capability, but up to now (to my google capabilities) no one succeeded in connecting any external I/O!

I'm pretty sure about the wirings (at least according to pure guessing from your schematics) as I checked all of them with a tester.
The wiring I made is quite simple
on the micro USB side:
contacts 4 and 5 bridged
Data wires connected to its corresponding ones on the female USB.
Power and ground on the female USB taken from an male USB connected to a charger.
Anything wrong?

Now it comes the detail requests:
1) What does it happen when you connect your cable to the Razr. Does it recognize it in some way giving any notice?
2) Rooted is needed? (Mine is not yet rooted).
3) Any special setup/tweaking to have OTG working?
4) Where do you access the external I/O contenct? From a directory in \SDcard otherways where else? Can you name it?
5) What I/O have you succesfully connected? Any kind of memory stick works? Any kind of HD? Mouse? Keyboards?

Thanks in advance in the name of all of the Razr's users interested in usb host functionality!:D
 

Karmarock

Senior Member
Dec 5, 2007
95
5
You would have to connect ground from the charger to the phone also.

Thanks Pajn for the suggestion, actually updated the wirings but with no luck!
Are you currently using a cable like this to connect devices to your Razr?
If the following questions could be answered at least we would know what to expect when the wirings are correct!

Now it comes the detail requests:
1) What does it happen when you connect your cable to the Razr. Does it recognize it in some way giving any notice?
2) Rooted is needed? (Mine is not yet rooted).
3) Any special setup/tweaking to have OTG working?
4) Where do you access the external I/O contenct? From a directory in \SDcard otherways where else? Can you name it?
5) What I/O have you succesfully connected? Any kind of memory stick works? Any kind of HD? Mouse? Keyboards?

Thanks in advance in the name of all of the Razr's users interested in usb host functionality!:D

@Kholk
Some words about your experience are eagerly waited with great anticipation!
 

pajn

Senior Member
Aug 13, 2009
225
109
Thanks Pajn for the suggestion, actually updated the wirings but with no luck!
Are you currently using a cable like this to connect devices to your Razr?
If the following questions could be answered at least we would know what to expect when the wirings are correct!
To bad it didn't work :(
No I have not tested. I proposed it because it have to be so electrically. If you don't connect ground the phone have no possibility to read the signal.
IE. if you power to things from different sources you should always connect the ground.

I don't have a cable so I can't test myself :(
 

kholk

Retired Recognized Developer
May 20, 2007
2,293
3,829
Torino
What an incredible news! :eek:
There are quite a bunch of posts around about Razr USB host capability, but up to now (to my google capabilities) no one succeeded in connecting any external I/O!

I'm pretty sure about the wirings (at least according to pure guessing from your schematics) as I checked all of them with a tester.
The wiring I made is quite simple
on the micro USB side:
contacts 4 and 5 bridged
Data wires connected to its corresponding ones on the female USB.
Power and ground on the female USB taken from an male USB connected to a charger.
Anything wrong?

Now it comes the detail requests:
1) What does it happen when you connect your cable to the Razr. Does it recognize it in some way giving any notice?
2) Rooted is needed? (Mine is not yet rooted).
3) Any special setup/tweaking to have OTG working?
4) Where do you access the external I/O contenct? From a directory in \SDcard otherways where else? Can you name it?
5) What I/O have you succesfully connected? Any kind of memory stick works? Any kind of HD? Mouse? Keyboards?

Thanks in advance in the name of all of the Razr's users interested in usb host functionality!:D

The first try was with the Motorola LapDock, the second one with a custom USBOTG cable.

When you connect the RAZR to the USBOTG cable or to a LapDock, it says that a dock has been connected to the device (HD Multimedia Station or LapDock, both are recognized as docks, obviously).
So you have to connect something to your RAZR and it will be instantly recognized but the USB Device Connected notification is shown only in WebTop, not in Android.


The USBOTG cable HAS TO give power to the RAZR and to the devices you're connecting to it, otherwise the RAZR won't recognize the Dock Connected status.
Be sure your AC power is 5V with at least 1A, otherwise there won't be enough amperage for RAZR and the connected device and since the RAZR has got the priority, you'll only charge the device's battery and your connected USB device won't have the necessary power for working correctly.


ROOT is not needed for OTG USBHost operation as the device has been configured by Moto to work in USBHost Mode.
When you connect an external pendrive, the device will automatically create a device node and will automatically mount the connected pendrive/USBHDD in a directory created in /mnt.

I've successfully connected all the device I was able to use on ATRIX, including keyboards, mouses, an 8GB PenDrive and a 500GB external HDD.
I'm also about to see if I can do a modification to the ATRIX LapDock for including into it another USB HUB and a switchable (ON/OFF) 2.5 250GB SATA->USB HDD. If I'll success in this, I'll also post on xda-developers a thread with the instructions on how to do that.
 
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    @Karmarock

    micro-usb-b.jpg

    1 VCC Red +5 V
    2 D− White Data −
    3 D+ Green Data +
    4 ID none Mode Identification
    5 GND Black Ground

    LapDock:
    +5V and GND connected directly to the battery of the LapDock, TX+RX connected to the integrated USB HUB.

    Docking Station:
    +5V and GND connected directly to external power (5V AC), TX+RX connected to the integrated USB HUB.

    Oh, in BOTH, for enabling the Host Mode, pins 4 and 5 are shortcircuited, exactly as the USB OTG specifications.
    3
    Success at last!!!

    Used an external HUB and a new OTG cable [credits to Kholk].
    Didn't worked with the external power from the HUB (actually didn't recharge the Razr).
    Worked using Y wire.
    Could only access pendrives when connected to the HUB.
    Very strange as I supposed it should also work just connecting directly any memory stick to the OTG cable (powered with the Y cable)! Instead an USB HUB is required!
    Checked back and actually this configuration works also with the samsung cable (this confirms to me its a real OTG cable, I was so desperate that came to thinking it was just plain plug converter).
    So maybe I made 3 working OTG cables, but was checking the wrong configuration!

    To my great surprise the Razr dretects when the device is connected (just wait for a bunch of seconds) and lets you also explore it and unmount it even without using webtob (just select the option from the USB Icon that will appear in the upper bar).

    The good news (not to me as I wasted a lot of time soldering) is that this setup can be obtained with standard cables:
    -Any real OTG micro USB male to USB female
    -Any USB male to mini USB male Y cable with extra USB male just for power (standard for some external HDD)
    -An external USB Hub with female mini USB in.

    Before updating my first post will do some more experiments and let you know about the findings.
    3
    I successfully got OTG functionality working! It took a little modification of some standard USB cables, but here's how I did it:

    I ordered a USB OTG cable (Micro USB male to USB Female) from Ebay for $1.99, including shipping.
    I had a USB extension cable (USB Male to USB Female) that I purchased from the dollar store (for $1.00)
    I had another outdated USB cable (Mini USB) that I no longer used

    Cut the USB extension cable in half and strip all 4 wires inside (on both cut ends).
    Then cut off the Mini USB end of the Mini USB cable. Strip the 4 wires (mine was strictly a charging cable, so it only had 2-red and black).
    Connect the white and green (data) wires of both ends of the USB extension cable, being careful to insulate each wire from touching one another.
    Connect the red and black wires to each other as well, and connect the black and red wires from the third cable (JUST the black and red wires are needed).

    Voila! Now plug the OTG cable into your phone, and use the extension cable as a normal extension cable to connect your USB devices. Then take the extra cable (the one with just the black and red wires connected) and plug it into your USB wall charger. There you go! If you did everything right, this should work perfectly!

    I just wrote this entire post using my OTG setup with a hub, a USB mouse, and a USB keyboard.

    Sent from my DROID RAZR Maxx using XDA Premium
    1
    Dismounted a micro usb male to USB female cable, to my surprise found it with connection 4 free.
    Hence made the 4-5 bridge and checked again.
    Yet no usb host connectivity with an external powered 2.5 HD.
    The HD happened to charge the Razr.
    Hence modified the cable disconnecting the +5V.
    Now I should have an OTG cable with an external powered devices.
    As soon as I'll find back my USB Y cable I'll check with it and some external devices to see if any of them is recognized right out of the box.

    Yet I suspect that, like the Razr Upon USB connection let you choose between some differents kind of connections, maybe some settings has to trigger host mode.
    Any idea?