OTG Host mode while charging - Nexus 7 Q&A, Help & Troubleshooting

Hi,
OTG specifications tells it is possible by using a special resistor on id pin.
Does the N7 compatible ? with stock kernel ?
Sent from my Nexus S using xda app-developers app

I've tried a USB hub powered from the Asus charger. The hub "input" USB connector showed 5.17v (not tested with a load) - don't know if a USB hub should expose a voltage to the USB host and as hubs go this is as cheap as they get. Connected up to GNex (much prefer GooN!!) with OTG. There is no indication of charging taking place - Android System Info continues to report that the battery is discharging. Added two USB sticks and an SD card StickMount mounted them but no change re charging.

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[Q] usb otg gamepad question

I have an otg cable, yet none of my accessories work with it and my RAZR MAXX. My question is whether or not I need a powered hub when using the OTG cable. I have seen set ups of other android models using a SIXAXIS controller and otg cable, yet no hub. In this case, it the powered hub not needed since the controller itself is supplying its own power?
Thanks,
Neverused
USB controllers don't work?? I'm interested in this as well
Sent from my Xoom using xda app-developers app
Download USB Device Info:
https://play.google.com/store/apps/details?id=aws.apps.usbDeviceEnumerator
When you open the app you should see 0 devices under Android and Linux tabs. Now connect just your OTG cable nothing plugged into it and hit refresh, something should show up, usually under the Linux tab that identifies the USB host. Even if the USB host doesn't supply power this will still work as I have tested it on my Touchpad which has no OTG power.
If you saw something appear when you connected the OTG cable, than OTG is in the Razr M. Now try connecting your gamepad and refresh the device list. If its not showing up then there is either something wrong with OTG or you need external power. This program will ID any USB device connected, even those which Android doesn't support since its just matching the device against a list it has. Try getting a USB keyboard/mouse working ad those are universally supported on Android and would confirm if USB host works.
Questions go in the question forum too...
Here's a dumb question. I just ordered a female USB to male micro USB. I wanted to be able to yank pics off my camera and drop them on my phone. Would I need an OTG adapter or does that plane adapter work?
Sent from my XT907 using xda premium
agent888 said:
Here's a dumb question. I just ordered a female USB to male micro USB. I wanted to be able to yank pics off my camera and drop them on my phone. Would I need an OTG adapter or does that plane adapter work?
Sent from my XT907 using xda premium
Click to expand...
Click to collapse
An OTG cable has a extra pin in it that is tied to ground in a OTG cable which tells the hardware to switch to OTG mode. A regular USB cable will leave this pin open.
If I'm able to peel open this adapter that I got, and jump pin 4 to 5 should it work as an OTG cable?
Sent from my XT907 using xda premium
agent888 said:
If I'm able to peel open this adapter that I got, and jump pin 4 to 5 should it work as an OTG cable?
Sent from my XT907 using xda premium
Click to expand...
Click to collapse
Its possible, as shown here:
http://tech2.in.com/how-to/accessor...sb-otg-cable-for-an-android-smartphone/319982
For me I'd rather just buy an OTG cable, but if you have regular microUSB cables laying around, go for it.
Bought an OTG cable
Bought a simple OTG adapter from newegg. So far....plugged in a mouse and my camera. Both work flawlessly, my camera gives me the choice of either either MTP (?) that goes straight to gallery and image import, or Storage which prompts to a new usb mount. Have not tried a gamepad yet, I have 2 floating around somewhere but not sure what game to try.

What's the differences between OTG cable and the one that comes with the Nexus 7?

Sent from my Nexus 7 using xda premium
An OTG cable is not for charging/connecting your device to a computer. Instead of usb micro to a male usb, it's micro to female usb, so you can plug in peripherals and flash drives etc. to your device.
Sent from my SGH-I777 using xda premium
When a normal USB is plugged in, the Nexus is in "slave" mode. Receives instructions.
When an OTG cable is plugged it allows it to be in "master" mode. Can give instructions.
Sent from my Nexus 7
Stop... MUFFIN TIME!!!
There are basically 3 types of cables you can plug into the USB port of a Nexus 7:
1. A normal USB-to-microUSB cable, plugged into a computer or a USB charger. Either way it charges, and if it is hooked to a computer the N7 is in Client Mode and you can transfer files as well.
2. High-current chargers (like the one that comes with the Nexus 7). The data lines on these are shorted together; this tells the Nexus to accept higher current on the power lines for faster charging.
3. OTG cables have the normal 4 wires on the USB end - two for power, two for data - but on the microUSB end there is a fifth connection called USBID. Normally (as when using a normal 4-wire USB cable) the USBID pin is floating, i.e. not hooked to anything. On an OTG cable, the USBID pin is connected to the ground wire. This tells the N7 that an OTG device is plugged in, which causes it to do two things: it reverses the current on the power lines - because it needs to power whatever you have plugged into the OTG cable, like a USB card reader or keyboard - and it switches the USB interface from Client Mode (which it uses when it is plugged into a computer, because in that instance the N7 is a peripheral device) to Host Mode (because in that instance the OTG device is the peripheral and the N7 is the 'computer').
There is one other option for charging: the pogo pins on the side. (The 4 pins are 5V, stereo left, stereo right, and ground.) Providing power to the pogo pins (as when it is put in a dock) tells the N7 to accept high current on the pogo pins. Momentarily connecting 5V to the right stereo channel tells the N7 that external speakers are connected and it starts driving audio out the two center pogo pins. When this is happening the charging takes place through the dock, the USB connector can be used with a data cable or an OTG device, but no charging takes place through USB when the dock is connected. (An OTG device is still powered by the N7, but current never goes the other way.)
Mechanio said:
There are basically 3 types of cables you can plug into the USB port of a Nexus 7:
1. A normal USB-to-microUSB cable, plugged into a computer or a USB charger. Either way it charges, and if it is hooked to a computer the N7 is in Client Mode and you can transfer files as well.
2. High-current chargers (like the one that comes with the Nexus 7). The data lines on these are shorted together; this tells the Nexus to accept higher current on the power lines for faster charging.
3. OTG cables have the normal 4 wires on the USB end - two for power, two for data - but on the microUSB end there is a fifth connection called USBID. Normally (as when using a normal 4-wire USB cable) the USBID pin is floating, i.e. not hooked to anything. On an OTG cable, the USBID pin is connected to the ground wire. This tells the N7 that an OTG device is plugged in, which causes it to do two things: it reverses the current on the power lines - because it needs to power whatever you have plugged into the OTG cable, like a USB card reader or keyboard - and it switches the USB interface from Client Mode (which it uses when it is plugged into a computer, because in that instance the N7 is a peripheral device) to Host Mode (because in that instance the OTG device is the peripheral and the N7 is the 'computer').
There is one other option for charging: the pogo pins on the side. (The 4 pins are 5V, stereo left, stereo right, and ground.) Providing power to the pogo pins (as when it is put in a dock) tells the N7 to accept high current on the pogo pins. Momentarily connecting 5V to the right stereo channel tells the N7 that external speakers are connected and it starts driving audio out the two center pogo pins. When this is happening the charging takes place through the dock, the USB connector can be used with a data cable or an OTG device, but no charging takes place through USB when the dock is connected. (An OTG device is still powered by the N7, but current never goes the other way.)
Click to expand...
Click to collapse
Dont forget a "y cable", which can charge and preform host mode (otg) at the same time, only at a slower charging rate. This is providing you are using a kernel that supports this function. "Otg+host mode charging"
Sent from my Nexus 7 using xda premium

[Q] Pogo pins and OTG question [simultaneous charge & OTG?]

I'm wondering if anyone knows if it's possible to have simultaneous OTG & charging with the use of a pogo pin charger?
For instance, plug in a usb OTG into the main microUSB charging port, and use a pogo pin charger [either make one or buy when they are available], and have a flash drive, or hard drive plugged in, and charge at the same time with the pogo pin connector?
I used to have a Nexus 7, and via a custom kernel, and a OTG charging cable [basically a regular OTG with additional power wires & connector for charger]. But I think it would be simpler to use the pogo pin approach. The only thing I'm worried of however, the kernel might disable OTG while it charges via pogo, or perhaps disable charging while OTG is enabled. I guess in this case, we would need a modified kernel to achieve simultaneous OTG and charging.
Here is a link to one of the first Nexus 10 pogo charger cables and it makes this claim:
"You still can power Nexus 10 while the USB port is otherwise occupied for data uses. It is fun & convenient to have MagNector to free up the USB port and charge faster."
http://www.ebay.com/itm/MagNector-N...ader_Chargers_Sync_Cables&hash=item20ce4990a6
So if that statement is true than the answer to your question is Yes.
eBay item is no longer available..
However, I know how sellers often make unfounded claims like that. So while it's probably a good sign, I am not convinced it's true. If anyone is fortunate enough to have a pogo charger, could you test it out with a otg cable and let us know the results?
Or if you're a kernel hacker, maybe take a look at the kernel source code and tell me what you think?
Also if anyone has a link where I could read about pogo pins for the N10, I'd like to read it. I'm interested in trying to make one, if they don't make any low-cost ones in the near future.
:bump:
mvmacd said:
eBay item is no longer available..
However, I know how sellers often make unfounded claims like that. So while it's probably a good sign, I am not convinced it's true. If anyone is fortunate enough to have a pogo charger, could you test it out with a otg cable and let us know the results?
Or if you're a kernel hacker, maybe take a look at the kernel source code and tell me what you think?
Also if anyone has a link where I could read about pogo pins for the N10, I'd like to read it. I'm interested in trying to make one, if they don't make any low-cost ones in the near future.
Click to expand...
Click to collapse
The answer to the question is ye, you can charge and use otg. Btw, http://pogocable.com/ 20$ isn't a bad price...
lKBZl said:
The answer to the question is ye, you can charge and use otg. Btw, http://pogocable.com/ 20$ isn't a bad price...
Click to expand...
Click to collapse
Just wondering, have you actually tried it yet? I remember on the n7 it would disable pogo charging when you plugged in otg. I hope n10 is different.
Swiped from my Nexus 10 using xda-developers app
I got the pogo cable in today. I plugged the usb-otg cable into the Nexus 10 with a thumbdrive connected to it. Stickmount recognized the thumbdrive and I can read/write to it. I noticed that the battery runs down while the otg is plugged in though. Running Paranoidandroid 2.99 with whatever kernel comes with that.
bd177 said:
I got the pogo cable in today. I plugged the usb-otg cable into the Nexus 10 with a thumbdrive connected to it. Stickmount recognized the thumbdrive and I can read/write to it. I noticed that the battery runs down while the otg is plugged in though. Running Paranoidandroid 2.99 with whatever kernel comes with that.
Click to expand...
Click to collapse
Does it say "Charging (USB)" or "Charging (AC)" in Settings > Battery?
mvmacd said:
Does it say "Charging (USB)" or "Charging (AC)" in Settings > Battery?
Click to expand...
Click to collapse
It says "Charging (AC)"
I know it's not the original question, but it looks like that would be possible with a modified OTG USB cable. Sounds like you already have something similar.
I was thinking about this for using my n10 for larger video recording when away from wifi. Just need to hook a battery up to the OTG while its plugged into the thumb drive. It takes a charge off my laptop when connected via the otg usb, so it should work as well with the correct setup voltage/wiring .
I would also like to know the pin designation for the pogo plug. If you can do the same setup as the one above, with the pogo... There would be less chance of damage to the tablet on the go......
metaled222 said:
I know it's not the original question, but it looks like that would be possible with a modified OTG USB cable. Sounds like you already have something similar.
I was thinking about this for using my n10 for larger video recording when away from wifi. Just need to hook a battery up to the OTG while its plugged into the thumb drive. It takes a charge off my laptop when connected via the otg usb, so it should work as well with the correct setup voltage/wiring .
I would also like to know the pin designation for the pogo plug. If you can do the same setup as the one above, with the pogo... There would be less chance of damage to the tablet on the go......
Click to expand...
Click to collapse
I know a nonstandard OTG cable [a OTG charging cable, basically the same as a regular one, except it has female USB only connected to the charging pins] and a modded kernel allowed for simultaneous OTG + charge on the Nexus 7, but I'd rather not have to deal with that, as getting a separate pogo charger seems like a better option.
mvmacd said:
I know a nonstandard OTG cable [a OTG charging cable, basically the same as a regular one, except it has female USB only connected to the charging pins] and a modded kernel allowed for simultaneous OTG + charge on the Nexus 7, but I'd rather not have to deal with that, as getting a separate pogo charger seems like a better option.
Click to expand...
Click to collapse
It has to be a moded kernel to access the data in read/write mode? Nothing to do with charging, and correct?
What I was considering is a battery/usb hub combo. One that plugs into the micro usb port and the battery actually has a female usb port for the thumb drive (need root to write to the drive, but not to stream from it). Amazon carries lots of external batteries with micro usb connection and the female usb port.
I agree, the pogo would be much simpler and still allow data through the micro usb.
The pogo would be much better for portability for this type of use especially if it allows for faster charging. If no one has the pin layout, guess I'll wait to get mine and test them myself. 6 pins on the n10 itself so it's not a standard usb pin setup?
metaled222 said:
It has to be a moded kernel to access the data in read/write mode? Nothing to do with charging, and correct?
What I was considering is a battery/usb hub combo. One that plugs into the micro usb port and the battery actually has a female usb port for the thumb drive (need root to write to the drive, but not to stream from it). Amazon carries lots of external batteries with micro usb connection and the female usb port.
I agree, the pogo would be much simpler and still allow data through the micro usb.
The pogo would be much better for portability for this type of use especially if it allows for faster charging. If no one has the pin layout, guess I'll wait to get mine and test them myself. 6 pins on the n10 itself so it's not a standard usb pin setup?
Click to expand...
Click to collapse
No, on the Nexus 7, if you plug in a OTG cable [which basically grounds a certain pin, the only difference between micro OTG and micro to full size USB adapter], it disables charging through power pins, because it needs to send power to OTG device, for example, a flash drive. It needs +5V power.
So the kernel mod was to disable the output of power, so that it could instead receive power and charge, from the charger. [The charger also 100% powering the OTG device]
Even if you have an externally powered hard drive, it needs power to turn on, even if it uses a wall adapter for the actual power to run the device.
Here is the kernel I was talking about: http://mehrvarz.github.com/usb-host-mode-power-management-nexus7/
it was made by a rootzwiki user. some discussion here: http://forum.xda-developers.com/showthread.php?t=1934722
Check the images of the USB hub on the 1st link.
Just for the heck of it I plugged a USB cable connected to my PC into the Nexus 10 while the pogo was also connected. The Nexus 10 showed up on the PC as it normally does in the file explorer and I can transfer files back and forth as usual. I went to Settings -> Battery on the Nexus 10 and it showed "Charging AC". I then unplugged the pogo cable and the status changed to "Charging USB". Plugged the pogo back in and the status switched back to "Charging AC". Then to make sure the pogo was actually doing the charging, I watched 2 hours of Netflix with the screen set to full brightness. The battery went down only 2%, so I'm pretty sure the pogo was doing the charging.
Sv: [Q] Pogo pins and OTG question [simultaneous charge & OTG?]
Thanks for your test. However with Nexus 10 connected to pc it is not in otg/host mode. You need to connect for example an usb memory with a otg cable to test if charging work with host mode enabled. There seems to be some discussions going on claiming pogo charging is disabled in host mode on Nexus 10 as well. It would be really really stupid if that's the case and I can't for the world figure out how they could put this limitation in the kernel.
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Johan1976 said:
Thanks for your test. However with Nexus 10 connected to pc it is not in otg/host mode. You need to connect for example an usb memory with a otg cable to test if charging work with host mode enabled. There seems to be some discussions going on claiming pogo charging is disabled in host mode on Nexus 10 as well. It would be really really stupid if that's the case and I can't for the world figure out how they could put this limitation in the kernel.
Skickat från min HTC Desire via Tapatalk 2
Click to expand...
Click to collapse
Yes I tried that and the pogo would not charge.
EDIT: I bought a couple of OTG Y-cables on ebay (1 male micro usb end, 1 female micro usb end and a female usb end) to play around with when I saw they had a fix for the Nexus 7. I tried one on my Nexus 7 (PA rom and Timur kernel), connecting the female usb to a powered usb hub that has 16gb sdhc card plugged into it. Then connected the female micro usb end to a spare micro usb charging cable and the other end of the charging cable to the usb hub. The male micro usb end gets connected to the Nexus 7. I fired up the Nexus 7 while in the Asus pogo dock I bought for it and it charges the Nexus 7 while also allowing the OTG connection. I tried the same setup with my Nexus 10 (PA Rom, Ktoonez kernel) and pogo cable and it worked. The Nexus 10 charges through the pogo cable while the OTG works also. With the usb hub I'm using with the Nexus 10, I had to plug the charging cable into a charger wall wart. I don't think the old hub was putting out enough power to power the usb device. I let them both run over a day like this. Ran some RomToolBox app backups on both them and they both are charging on the pogo pins while doing so. If you go to system settings -> battery it shows "Charging AC" on both.
The galaxy nexus already has a custom kernel that supports OTG + charging (via a y-cable):
http://forum.xda-developers.com/showthread.php?t=1835720
In that thread (and the link in the OP there) there are discussions about porting that kernel to the nexus 7. Also, this modified kernel is (currently) for 4.1.2. Unfortunately I am not smart enough to do this myself (especially we are now dealing with the pogo cable and the USB); I do hope to let everyone -- especially the developers! -- knows about the possibility in view of the gnex kernel.
Is this an issue only with Disk Media over OTG, or is it with anything (controllers, etc.) over OTG?
If anyone is interested read my edit a couple of posts up.
Sv: [Q] Pogo pins and OTG question [simultaneous charge & OTG?]
It says AC charging even though it's not actually charging. Confirm this with for example battery monitor widget.
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Please help asap nexus 7 car install otg timurs usb not seeing usb power

I installed it in my dash and removing it is a pita it was working perfectly fine but for some reason it wasnt showings charge or turning off or on with the car it just stays on i tried restart nothing happens i tried unplugging usb from powergen and plugging back in no result
Also if i go to usb rom under fixed installation i am able to check box and uncheck also did nothing
I am using nexus 7, timurs usb rom, otg cable, original charging cable and powergen usb charger
Please help thanks
Anyone???
I'm also using Timur's kernel with USB ROM for my car installation. I know that it can be very picky on the order the USB plugs are added (data and power). It may seem simple but remove the the OTG cable from the tablet and remove both the data and power legs from the OTG as well. The follow the order listed by Timur on his website:
To activate charging, you must first connect your external power supply to your OTG Y-adapter - then plug the OTG adapter into your Nexus 7 - and then connect any slave devices.
Click to expand...
Click to collapse
Hopefully that should get you back up and working. I completely understand how frustrating it is to have everything plugged in and see that tablet isn't charging, especially when its difficult to get to the Nexus itself.
does anyone have a easy charging solution these car chargers dont work
and a good otg y cable
You could try using a power inverter which will give you a standard US plug from the cigarette lighter. From here, you could plug in a regular outlet adapter. I found this to work pretty well with my own set up and managed to get one pretty cheap at Walmart. As for a good OTG y cable, your best bet is probably to go on Amazon and find one with a lot of good reviews. They can vary in quality and some of the cheap ones I've gotten from China have flaked out after a short time and little use.
Sent from my Nexus 7 using xda app-developers app
Not seeing usb power
I had the same issue. I was using a 90 degree adapter into an OTG cable and my n7 wouldn't go into fixed install mode. Turns out my adapter cable was stopping the n7 from recognizing power. I removed the 90 degree adapter and plugged straight to otg and it worked as advertised. The issue was found during my bench testing on a 12v powersupply. I still have to find a 90 degree otg cable that will work.
So... try a different cable or if you have an adapter between the otg y cable, that may be the issue.

external battery with USB device?

I am using a Seek Thermal imager via the N10's USB OTG port. My battery is old and takes a dive when I use the imager. Roughly only an hour of use before it kills the battery. Obviously the thermal sensor draws power from the n10's battery.
I think I read somewhere that I cannot use the pogo plug to charge while using the otg. Is that correct? That would have been an ideal solution.
Would it be possible to use an external battery (14000mAh USB battery supply) and feed/splice it into the usb otg cable with the imager? What about a 4 port USB hub using the battery and thermal sensor plugged into the otg? Not sure since I don't think it works like a USB host and don't think you can back feed power via USB host port.
Any ideas? Could any of this work? Thanks for any suggestions!
Ed

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