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Ideapad K1 DIY Host Cable [Pinout] (Help Needed) !

36K views 22 replies 10 participants last post by  mjb32803 
#1 · (Edited by Moderator)
I'm tired of waiting for Lenovo host cable and that I cannot charge my tablet when I'm connected on the computer...
I want to add ports on the bottom like micro usb, standard dc connector and another one for usb host.
I know there space inside between the prop. connector and the right side. !

I'm compiling a Pinout but need someone that already have a host cable (some EU users receive one).
Please test each pin and post it here !!!
I will update a FULL pinout and pictures when completed

Update: The USB connector has every pins so I will use it !

Left Pic: TOP (Screen Side)
Right Pic: BOTTOM



01, 02, 33, 34: GND
07, 09, 11, 13, 28 : GND

17: +3V out when pin 30 grounded
18: +12V in (Charger)

04: Trigger Headphones when Grounded
30: Trigger USB Host ??? Output 3V on 17 when Grounded
31: Trigger USB Client (to PC) when Grounded

8, 10, 12, 14: Possibly Headphones Right, Left, Mic...

15: GND (Trigger ??)
20: GND(Trigger ??)

21: USB Client D-
23: USB Client D+
24: USB GND

There's no +5V out so maybe a trigger activate it !

Thanks for your help !
 
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#3 ·
Theory.

The connector is probably multi-use with solder connections based on use. From the looks of the printed circuit, pins 15, 20, and 31 are meant to be either soldered or unsoldered.

If pin 31 triggers usb client (and is currently grounding because that is a client cable), and grounding pin 30 triggers 3V on 17, perhaps pin 31 is keeping 17 from reaching 5V. Perhaps ungrounding 31, then grounding 30 will trigger host and give you 5V on 17 (can't have host and client at the same time)?
 
#5 ·
I wonder if the keyboard dock is actually using usb connections. My understanding is that the keyboard dock can be operated sans charger (it just won't be charging in use). If so, it may be possible that the keyboard is initiating the tablet into usb host mode. I don't know because I don't have a keyboard dock to test out.

By the way, does anyone know if the "proprietary" connector can be sourced from anywhere?
 
#8 · (Edited by Moderator)
#9 ·
Hi everyone I have looked at the spec USB chip smc USB3315, and also googled a lot about how does the OTG works.
And I came to the conclusion that grounding the ID pin of the USB3315 will activate OTG on K1. This what the datashee states:"ID pin of the USB cable. For non-OTG
applications this pin can be floated. For an A-Device ID is grounded. For a BDevice ID is floated."

Now the question is, which of all those pins is the ID pin ?
As soon as the ID pin is grounded I think that we will get the 5V on the VBUS pin which I think is the pin 24, labeled GND at the top of the post.

So the pin are
21: USB Client D-
23: USB Client D+
24: USB VBUS (+5V in OTG mode)

? : ID pin

If I find some extra time I will try to buy on ebay an extra USB data cable, and try to ground the unknown pin.
Or if Shaztech can try to ground pin 22, to see what happens....

Or if someone has bought the OTG cable and can measure the resitance between ground and all pins, we will apreciate a lot.
If pin is grounded the resitance should be 0.
 
#14 ·
Hi, Maybe this will help. I dismantled my K1 keyboard after loading a few USB diagnostic tools and discovering that it appears to be USB based.
The whole thing is held together with glue-tape. The top of the keyboard clips on around the edges and from the 'velcro' sound, clips are around each key as well. Not sure it will go back together without additional adhesives. Oh well. Ask any questions -- I'm not gluing it back together until I get a hub inside.


1. front tablet connector. L-R (USB wires, 2 unknown, 2 red/black power)
2. same just not as close.






4. circuit board adhesive taped to bottom of keyboard.
CON1 - dock wire connector
J13 - wires to power the white LED for CAPS LOCK
J14 - wires to keyboard

5. Hey, these are those wires for those connectors. QUICK NOTE: those black bits at the right of the picture are broken bits that held the top of the keyboard facia on. If you really want to open your keyboard, DO NOT pry off the top of the key facia. The bottom of the keyboard is held together with sticky tape, really strong sticky tape, but you can separate it. The base of the keyboard has wires that could be ripped in the prying. All mileage will vary, you have been warned.

 
#16 · (Edited by Moderator)
Hello alexsnow, hope this helps.

The R13 does not have markings. Probably a "0".
As for the bottom image of the K1 mount board. There is nothing there except pins through the board. no tracings. All tracings are what you see.

I did a little more testing one weekend before deciding that something more is needed besides just hooking up wires in the right order. The pin number used in the below diagram are from the circuit board and k1 mount. Not my own.



As per the keyboard dock
The P## are the larger sized pins; 8 in all. The S## are the tiny pins, 24 in all. The front pins are odd numbers and the back are even. Need to go buy some solid core wire to continue. ttfn.
The circuit board at the base of the connector has 4 wires coming off to the keyboard circuit board. Following the numbers theres #1: 5+V, #2: D+, #3: D-, #4: GND, #5: unused. What I can tell you is without resisters, there is barely enough juice coming from the K1 table along pings S04 and S24 to light a led, very dim. I suspect that the keyboard or any other device connected is designed to pull extra juice from P08 and create the full 5+ USB.

Did get one of those squid USB hubs from the local store, plenty of room to place the hub in the space behind the K1 mount and let the squid legs hang out on the side. The adapter is probably a plus to have or the battery will be drained quickly.

I really appreciate getting the ICS upgrade to the K1 from Khanning. Thank you
 
#17 · (Edited by Moderator)
Hello fwfr.ls. You are wrong. R13 is otg ID pullup resistor. P06 (blue)- +5v. S04 - otg ID pin. Pins D- D+ for the host and for the client are same. I connected id pin 68 kohm to GND and +5v appeared at one second and off. It works as a host (without +5v supply) if id pin unconnected. It works as a client if id pin connected to gnd. Interested near r13 via to the bottom side. where it is connected to. Intresting link http://4pda.ru/forum...=189536&st=2680
 
#18 ·
I went to that website and there is are two pictures that show a home made USB host/client switchable cable. The text next to the picture reads (compliments of google translate):

"The two thin white wires - switching USB host-client, when they are closed - USB client, are open - USB host. Two thick white wires - 12 for charging the tablet, do not have to always carry a charge, +12 V is at work and in the car, the USB does not have any relation. +5 V for USB comes from the tablet, and the key, which gives a voltage at pin terminal had opened "by hand", because has not yet figured out how it appears when you connect the "native" adapter. It is for this it is necessary to disassemble the tablet."

The problem I have is that I cannot seem to download the higher resolution photos to see HOW the two small white wires are connected? It seems they are very simple. If you have a way to post the pictures or can describe how the wires are connected that would be great.
 
#20 · (Edited by Moderator)
First post pins 19 - +5v host ; white - D-; Green D+; Next cable - +5v client; 31 - id pin; Cut the via near pin 31 from gnd and left unconnected. Short the +5v control switch inside tablet or correctly connect id pin. Waiting from fwfr.ls the bottom side of pcb board.
I used a needle and cut the circuit board trace from pin 31 (S4). Does pin 31 connect to ground through the hole that goes to the other side of the circuit board?
If I use a powered USB hub, I should not need +5 volt from the tablet.
How do I correctly connect the id pin (pin 31 yes?)
Is cutting pin 31 from ground all you need to do to activate usb host mode?
 
#21 ·
I have an after market USB data cable that does NOT ground pin 1. So far I have UN grounded pins 15, 20 and 30. These were the only ones that were grounded. All the connector pins are "floating" except for D+, D-, Data GND, and SHIELD GND.

Someone with a HOST cable... when you initially plug in the cable, do you get any message on the display? When I plug a host cable into my SGS3, I get a short popup that says "USB connector connected". Am just wondering if I should see the same type message on the tablet if the cable is configured correctly?
 
#22 · (Edited by Moderator)
Yup its now 2014 and im not sure anyone would still be interested in this anymore.

but who cares what anyone thinks....

For all of you that would like to build your own otg cable for the K1 i have attached an image of the official cable.

Sadly for some reason it doesnt work on my tablet :-( Ive also updated my K1 to K1_A301_21_03_120607 and running 4.0.3.

when i plug to my pc it works...but when i plug the otg nothing happens... tried a keyboard.... tried a usb key.... xbox 360 remote... nothing!

So for all of you who were once interested to get this cable, here is an image of the pinout!

Good luck!

https://www.dropbox.com/s/v8612v75d705v22/20140506_211340.jpg

https://dl.dropboxusercontent.com/u/11602860/20140506_230203.jpg
 

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