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Tablet [Q] Asus Memopad 7 HD Powered USB OTG + charger

OP KrameX

17th November 2013, 05:55 AM   |  #1  
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Hi.

I made a powered USB-OTG cable following this schema from sonic_boom, and it works perfect, usb pendrives in fat32 format works fine, keyboard and mouse too even at same time using an usb hub. But tablet's battery doesn't charge.




So, I tryed to made an usb otg cable + charging enabled. following this schema:



I used the 100K ohm resistor to shorten pins 4 and 5, like the guide and others post says, and tablet effectively is charging, but usb devices aren't longer recognized...

(by the color bands, these two must be 100K ohms resistors, I used these two, the small... and the smaller xD):




I tryed diferent resistors: 60K, 40K, even 20K and 10K, and tablet is charging up the battery, but usb devices are no longer recognized anyways.

Now I'm not using resistor, so I've got an usb-otg cable without charging tablet battery.

The fact that charging usb-otg are charging but not recognizing usb devices: would be a tablet (kernel) problem? or may I need to use another resistor?

thanks.


P.D. I think this can be a solution:



In this schema, one charger is for tablet (host) and other can power USB devices... but it is a bit messy use two chargers... I would preffer to use only one


P.D 2. Reading a lot, I found that different actions can be triggered depending on the measure of the resistor and that values are specific from each brand. These info is in the Kernel.

How can I know what are the resistors values for asus memo pad 7hd?
what is the file in that these resistors value are stored in android system?


example:
Quote:
Originally Posted by TheBeano

We've already established that a resistor on the micro USB port can be used to force the Galaxy S into download mode, but the USB switching chip used on the phone has a lot of other capabilities that are triggered by different resistors between pin 4 and 5 of the plug.

Update 6 March 2011: Confirmed modes so far:
Desk Dock: 365K (also works with 1K)
Car Dock: 619K

Code:
RID_USB_OTG_MODE,	/* 0 0 0 0 0 	GND 		USB OTG Mode              */
RID_AUD_SEND_END_BTN,	/* 0 0 0 0 1 	2K		Audio Send_End Button*/
RID_AUD_REMOTE_S1_BTN,	/* 0 0 0 1 0 	2.604K		Audio Remote S1 Button */
RID_AUD_REMOTE_S2_BTN,	/* 0 0 0 1 1 	3.208K		Audio Remote S2 Button                         */
RID_AUD_REMOTE_S3_BTN,	/* 0 0 1 0 0 	4.014K		Audio Remote S3 Button */
RID_AUD_REMOTE_S4_BTN,	/* 0 0 1 0 1 	4.82K		Audio Remote S4 Button */
RID_AUD_REMOTE_S5_BTN,	/* 0 0 1 1 0 	6.03K		Audio Remote S5 Button */
RID_AUD_REMOTE_S6_BTN,	/* 0 0 1 1 1 	8.03K		Audio Remote S6 Button */
RID_AUD_REMOTE_S7_BTN,	/* 0 1 0 0 0 	10.03K		Audio Remote S7 Button */
RID_AUD_REMOTE_S8_BTN,	/* 0 1 0 0 1 	12.03K		Audio Remote S8 Button */
RID_AUD_REMOTE_S9_BTN,	/* 0 1 0 1 0 	14.46K		Audio Remote S9 Button */
RID_AUD_REMOTE_S10_BTN,	/* 0 1 0 1 1 	17.26K		Audio Remote S10 Button */
RID_AUD_REMOTE_S11_BTN,	/* 0 1 1 0 0 	20.5K		Audio Remote S11 Button */
RID_AUD_REMOTE_S12_BTN,	/* 0 1 1 0 1 	24.07K		Audio Remote S12 Button */
RID_RESERVED_1,		/* 0 1 1 1 0 	28.7K		Reserved Accessory #1 */
RID_RESERVED_2,		/* 0 1 1 1 1 	34K 		Reserved Accessory #2 */
RID_RESERVED_3,		/* 1 0 0 0 0 	40.2K		Reserved Accessory #3 */
RID_RESERVED_4,		/* 1 0 0 0 1 	49.9K		Reserved Accessory #4 */
RID_RESERVED_5,		/* 1 0 0 1 0 	64.9K		Reserved Accessory #5 */
RID_AUD_DEV_TY_2,	/* 1 0 0 1 1 	80.07K		Audio Device Type 2 */
RID_PHONE_PWD_DEV,	/* 1 0 1 0 0 	102K		Phone Powered Device */
RID_TTY_CONVERTER,	/* 1 0 1 0 1 	121K		TTY Converter */
RID_UART_CABLE,		/* 1 0 1 1 0 	150K		UART Cable */
RID_CEA936A_TY_1,	/* 1 0 1 1 1 	200K		CEA936A Type-1 Charger(1) */
RID_FM_BOOT_OFF_USB,	/* 1 1 0 0 0 	255K		Factory Mode Boot OFF-USB */
RID_FM_BOOT_ON_USB,	/* 1 1 0 0 1 	301K		Factory Mode Boot ON-USB */
RID_AUD_VDO_CABLE,	/* 1 1 0 1 0 	365K		Audio/Video Cable */
RID_CEA936A_TY_2,	/* 1 1 0 1 1 	442K		CEA936A Type-2 Charger(1) */
RID_FM_BOOT_OFF_UART,	/* 1 1 1 0 0 	523K		Factory Mode Boot OFF-UART */
RID_FM_BOOT_ON_UART,	/* 1 1 1 0 1 	619K		Factory Mode Boot ON-UART */
RID_AUD_DEV_TY_1_REMOTE,	/* 1 1 1 1 0 	1000.07K	Audio Device Type 1 with Remote(1) */
RID_AUD_DEV_TY_1_SEND = RID_AUD_DEV_TY_1_REMOTE ,		/* 1 1 1 1 0 	1002K		Audio Device Type 1 / Only Send-End(2) */
RID_USB_MODE,		/* 1 1 1 1 1 	Open		USB Mode, Dedicated Charger or Accessory Detach */

Last edited by KrameX; 17th November 2013 at 06:26 PM.
13th December 2013, 08:32 PM   |  #2  
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You can try this:

http://mehrvarz.github.io/usb-host-m...gement-nexus7/
4th March 2014, 08:28 AM   |  #3  
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litte help for HD7
hello from (old ?) france
please, would you telle me if the hd7 tablet needs to be rooted (or unretooded ? in mean, do i have to let the tablet as i received it or do i have to do something more for using the micri usb port with the hd7)
THANK YOU for you answer : i wait to build the cable as you proposed to do so.
jean
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7hd, memopad, usb otg charging, usb-otg
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