Power + Data using OTG

General chit-chat on the Linx 7
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mbuckhurst
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Joined: December 23rd, 2014, 10:57 pm
Linx Tablet: Linx 7
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Windows Version: Windows 8.1

December 23rd, 2014, 11:17 pm

Firstly some disclaimers:

1) The manufacturing of these leads is seriously poor
2) There are definite differences between batches of the cables, so an identical cable may not work
3) I resoldered my microusb plug, so potentially I fixed a problem

The cable I used is a 4 USB port (3 data + 1 power) from Ebay, http://www.ebay.co.uk/itm/271641277647? ... EBIDX%3AIT you can purchase this in the UK or from Hong Kong, it only took a couple of days to arrive.

My cable arrived with the micro usb port case apart in transit, initially it worked for data or charge, but not both, but very quickly one of the cables broke of, I had to resolder all the cables back onto the micro usb plug, shortening them to get clean wire first. I don't think this is relevant but until I get a new replacement I can't test.

I had been experimenting with the BIOS and noticed there's an OTG option, that's disabled, I'd turned it on and off in the past, but under no circumstances would it allow charging using a standard OTG cable, hence the purchase of the 4 port cable that supposedly worked with a Galaxy S4.

I'd forgotten about this setting in the BIOS, until it was mentioned on the HUKD deal for the 8" (Soza), I'd not tried it before, anyway, setting this option to PCI, rebooting the tablet with the cable plugged in and set to charge, and a couple of devices connected, for the first time ever, I see activity on the data wires, into the OS and it's working, I've got it charging and can still see a wireless keyboard + USB memory chip, I suspect the charge may be slower, but it's stopped Windows complaining of low battery, so it seems to at least be recognised by the OS.

The exact method I followed:

1) Plug 4 port cable into USB on tablet, with the switch set to data and keyboard plugged into one of the data ports.
2) Boot to BIOS - Hold DEL key as soon as you see the LINX logo.
3) Navigate to the Chipset menu using the arrow keys on your keyboard
4) Using the down arrow select the South Bridge option (it goes white when selected)
5) Press Enter
6) Using the down arrow select USB Configuration
7) Press Enter
8) Using the down arrow select USB OTG Support
9) Press Enter and select PCI mode from the popup menu
10) Press Esc twice to get back to the main menu
11) Use the arrow keys to get to the Save & Exit menu
12) Select Save Changes and Exit

Initially I had the cable plugged in, set to charge, plus the USB devices in their sockets, booting the tablet had them recognised and working. I've since tested plugging in and out of the tablet, and in all cases if it's set to charge, it will charge and have data.

I've tried with a Playbook micro-usb charger and external battery pack (2.1A) and in all cases the tablet believes it's charging whilst still showing data devices.

Changing power sources disconnects the USB devices, which promptly reconnect once power is re-applied.

mike
Dann
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Linx Tablet: Linx Vision
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Windows Version: Windows 10 Pro

December 23rd, 2014, 11:47 pm

great first post! :)
Dann
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littlefeck
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Joined: December 31st, 2014, 1:06 am
Linx Tablet: Linx 7

December 31st, 2014, 1:19 am

thank you very much. i was tring this today. even made my own cable to try different resistor values from id sense to ground. the samsung cable uses 65k ohms so will try tomorrow and report back. i never even thought of the bios. cheers mike!

jamie
WeeblBull
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Joined: December 31st, 2014, 2:29 pm
Linx Tablet: Linx 7
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December 31st, 2014, 2:35 pm

Just thought I'd register and leave a quick note to say that it worked for me too! I bought the hub / fly lead OP linked to, changed the bios settings (PCI Mode and the option below it - can't remember what it says but it is literally directly below), set the cable to charge and all my USB devices worked a treat whilst the battery was being charged.

This has been a godsend as I was deliberating how much I'd be using the tablet without being able to connect devices and charge at the same time.

Cheers,
Paul
grandwazoo
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Joined: January 2nd, 2015, 3:17 am
Linx Tablet: Linx 10
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Windows Version: Windows 10 Home

January 2nd, 2015, 3:25 am

Yep, me too - can confirm it needs both BIOS options changing for it to work :)
colincliff
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Joined: December 28th, 2014, 6:33 pm
Linx Tablet: Linx 8
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Windows Version: Windows 10 Home

January 2nd, 2015, 8:42 am

Can anyone confirm how quickly this charges? I have the 8 inch and despite the tablet claiming that it is charging when plugged into a powered use hub it seems to be such a slow charge that it is still discharging all the time when in use.

I was hoping to be able to use this as a small desktop replacement when traveling with work connected to a monitor and keyboard etc for the day if needed but at the moment this wouldn't work
littlefeck
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Joined: December 31st, 2014, 1:06 am
Linx Tablet: Linx 7

January 2nd, 2015, 10:08 am

It does charge but remember the standard charger is only designed to charge the device and not power usb devices at the same time. When using the otg charging cable, all connected devices use the power from the adapter not the tablet. I have reservations if the included charger does in fact output the claimed 1.5 amps. Your best bet is to use a minimum of a 2 amp adapter and you will see dramatic improvement.
colincliff
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Posts: 14
Joined: December 28th, 2014, 6:33 pm
Linx Tablet: Linx 8
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Windows Version: Windows 10 Home

January 2nd, 2015, 11:26 am

thanks littlefeck - i'll try getting hold of a better usb adapter and post back any improvement.
K1lo

January 2nd, 2015, 4:25 pm

littlefeck wrote:I have reservations if the included charger does in fact output the claimed 1.5 amps. Your best bet is to use a minimum of a 2 amp adapter and you will see dramatic improvement.
That was my feeling on the subject also... but a silly part of my was worried about using a differently rated wall adaptor :shock:
littlefeck
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Joined: December 31st, 2014, 1:06 am
Linx Tablet: Linx 7

January 2nd, 2015, 7:40 pm

As long as the voltage is 5v youll be fine. if you had a 5 amp adapter it only means it can supply up to 5 amps. if the tablet only needs 1 amp then it will only take 1 amp. The wall adapter will not "push" more current providing the 5 volts is correct.
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