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Can you charge & USB Host mode simultaneously?

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nexus-fan

nexus-fan

Android

  • 141 posts

Posted 23 November 2012 - 12:51 PM #141

Very strange... because for anyone else it doesnt works...
when i unplug the charge cable for 2 min (N7 in sleep mode) i must restart the tablet
for using DAC. (even if i plug it again).
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GoldMembr

GoldMembr

Average Android

  • 7 posts

Posted 23 November 2012 - 02:11 PM #142

Hi GoldMembr,
yes it is possible. More on this coming very shortly.

Here a little survey for you Nexus 7 owners: on what system would you rather see USB host mode updates becoming available?

a. JB 4.1.x stock
b. JB 4.2 stock
c. CM10
d. CM10.1

Edit: damn smilies B)


That is awsome news. I vote for stock 4.1.2 and cm10.
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Timur

Timur

Android Master

Posted 23 November 2012 - 02:58 PM #143

Does anybody know how I can convert that IMG kernel file to a flashable zip so I can swap back and forth between Trinity kernel and this USB OTG+Charge kernel in Recovery instead of fastboot via computer?


Here an alternative: backup both installations in CWM. Then switch between kernels by selecting "advanced restore" and by then picking only to restore the boot partition of choice.

What DAC are you using?
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RWNube

RWNube

Android Beginner

  • 81 posts

Posted 23 November 2012 - 07:18 PM #144

Here an alternative: backup both installations in CWM. Then switch between kernels by selecting "advanced restore" and by then picking only to restore the boot partition of choice.

What DAC are you using?

Hm, it seems I'll have to migrate from TWRP, but that sounds like a good idea. I am using the Fiio E17, which works with Trinity kernel as well as this OTG + Charge kernel. I can use the Fiio E17 with the USB Charge setting (in the E17's menu options) enabled or disabled... on both kernels. This is cool because I know that the power draw from the E17 doesn't cause issues with the Nexus 7. In my car, I'll use the OTG + Charge cable, when I am traveling, I'll probably use Trinity kernel, as I won't need to provide power to anything and I can run on the DAC and Nexus 7 batteries.
It seems that the Galaxy Note II won't support the E17 :( I may be looking at the E18 down the road, but for now at least the Nexus 7 is gonna rock it in the rock and beyond! I'm using a Netbook in the car with infrastructure mode enabled to stream music to the Nexus 7.
If anybody is interested, check this out:
I made batch files to start and stop the infrastructure access point on the netbook. Remember, this requires Windows 7 (dunno about Windows 8).

P.S. Because of this kernel, I can now plug my 2TB My Passport Western Digital hard drive into the Nexus 7. I just have to ensure that I am providing power to the USB OTG Y-Cable and then I connect the Nexus 7. Stickmount allows me to access the entire contents of the drive. It is formatted as NTFS. I have Paragon installed, but it is frozen via Titanium Backup. All I know is that it mounts and I can stream content from the hard drive. I will likely pick up a power pack like this one: http://www.androidpo...for-just-53-50/

Thanks Timur, you da man!
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dmexs

dmexs

Member

  • 23 posts

Posted 24 November 2012 - 11:19 AM #145

Hi GoldMembr,
yes it is possible. More on this coming very shortly.

Here a little survey for you Nexus 7 owners: on what system would you rather see USB host mode updates becoming available?

a. JB 4.1.x stock
b. JB 4.2 stock
c. CM10
d. CM10.1

Edit: damn smilies B)


B and D. Is there any reason why one would want to stay with the older versions?

My current issue: I haven't done extensive testing yet but it seems when my N7 is doing intense work (i.e. Navigation via Google Maps) the battery drains (maybe only about 3%/hour). It says charging but says USB instead of AC. This is even though the car power supply I'm using is offering up 3A of 5V to my Y-cable. (I'm using a CNX-P2140 from carnetix/mp3car, on the secondary channel) However, when I plug the whole setup, Y-cable, harddrive and all in to the stock N7 charger, it charges much faster and the battery settings page says Charging AC. Any thoughts?

My current (pun not intended :)) is that perhaps the voltage on the car's power supply is running just a little under 5V, maybe due to running such a long length of wire from the trunk to the dash? I'm going to test the voltages on the stock charger and the car power supply and report back.
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goatcatcher

goatcatcher

Average Android

  • 5 posts

Posted 25 November 2012 - 01:44 AM #146

Very strange... because for anyone else it doesnt works...
when i unplug the charge cable for 2 min (N7 in sleep mode) i must restart the tablet
for using DAC. (even if i plug it again).


+1
When power is removed from the hub powering the DAC and the N7 (ie simulating ignition off in vehicle) and the tablet is put into sleep for any period of time, on wake and re-power of the hub the DAC is not re-connected until reboot. I've spent hours experimenting with the order of events, cables, timing etc, but this always happens.
Running Paranoid Android 2.52 with Shek H1 DAC.

@RWNube - can you confirm this doesn't happen for you?
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GoldMembr

GoldMembr

Average Android

  • 7 posts

Posted 25 November 2012 - 02:57 AM #147

My current issue: I haven't done extensive testing yet but it seems when my N7 is doing intense work (i.e. Navigation via Google Maps) the battery drains (maybe only about 3%/hour). It says charging but says USB instead of AC. This is even though the car power supply I'm using is offering up 3A of 5V to my Y-cable. (I'm using a CNX-P2140 from carnetix/mp3car, on the secondary channel) However, when I plug the whole setup, Y-cable, harddrive and all in to the stock N7 charger, it charges much faster and the battery settings page says Charging AC. Any thoughts?

My current (pun not intended :)) is that perhaps the voltage on the car's power supply is running just a little under 5V, maybe due to running such a long length of wire from the trunk to the dash? I'm going to test the voltages on the stock charger and the car power supply and report back.


The reason i chose Stock 4.1.2 and CM 10.0.0 is because of the issuse and restrictions people seem to be having with the upgraded JB 4.2 that are not present in JB 4.1.2

Edited by GoldMembr, 25 November 2012 - 02:59 AM.

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dmexs

dmexs

Member

  • 23 posts

Posted 25 November 2012 - 09:08 AM #148

The reason i chose Stock 4.1.2 and CM 10.0.0 is because of the issuse and restrictions people seem to be having with the upgraded JB 4.2 that are not present in JB 4.1.2


Oh, interesting. Which restrictions do you speak of?
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kevincat3556

kevincat3556

Android Lover

  • 177 posts

Posted 25 November 2012 - 02:34 PM #149

I have an idea. disconnect the +5v from the usb cable between the N7 and the usb device, and put the N7 +5v on to the charger, and use an external power source for the USB devices. but make sure the ground is shared. or rig a diode in the line
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Timur

Timur

Android Master

Posted 25 November 2012 - 03:00 PM #150

Hi. I just made a brand new "USB host mode power management" kernel available for download to your Nexus 7. It can be found here: http://mehrvarz.gith...ent-nexus7.html
This is for use with stock Android 4.2. The USB power management extension is fully rewritten and now supports automatic transitions of power modes. Such as from externally powered host mode to OTG host mode.
My impression is that 4.2 kernel is the best choice going forward. It has a great number of fixes added to it and seems to be very stable. Want to get an impression on the number of patches incorporated between 4.1 and now? Take a look at this: https://github.com/m...grouper/network
Move left to mid June and then follow the dotted pink line towards the right. My work is based on the Nov 2 branch "android-tegra3-grouper-3.1-jb-mr1".
I hope this will let you use your USB devices more smoothly.

Edited by Timur, 25 November 2012 - 03:08 PM.

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