Nexus 7 POGO GPIO PINS on Side

peterpressure

Member
Jul 23, 2012
18
10
0
So similar to what was found on the Samsung Galaxy Nexus, does anyone know where the source file exists that explains what the 4 POGO pins on the left side of the Nexus 7 are for? I cannot figure them out with my multimeter or oscilloscope.

Samsung Galaxy POGO thread: http://forum.xda-developers.com/showthread.php?t=1614287
File on Samsung Galaxy Nexus was board-tuna-pogo.c but that is obviously not on the Nexus 7 because it is made by Asus and I assume they had a different file.


Close up of the POGO insternals from ifixit.com:
 

kpjimmy

Senior Member
Jan 20, 2009
4,990
1,115
253
47
San Antonio TX
My assumption is that there will be a dock of some sort that will be using those contacts.

I make this assumption from my old Nexus One where they also had contacts similar for charging. :confused:
 

OriginalFire

Member
Jul 6, 2012
40
10
0
I'm not entirely sure, but one of the pins could be for charging and another for ground. And possibly the other two are for audio out.

Just a guess lol

Sent from my HTC One X using xda app-developers app
 

tomascivinod

Senior Member
Sep 2, 2009
62
2
0
Sydney
Since there are 4 pins, I get the feeling it could be USB? 2 for data + 2 for power and since now Android has support for USB audio it wouldn't matter? I just wonder how you could do power and stereo audio since you would need a ground + 2 for audio and 2 for power...
 

khaytsus

Senior Member
Apr 8, 2008
7,263
1,176
243
Central Kentucky
Since there are 4 pins, I get the feeling it could be USB? 2 for data + 2 for power and since now Android has support for USB audio it wouldn't matter? I just wonder how you could do power and stereo audio since you would need a ground + 2 for audio and 2 for power...
Nope, ground is ground. Could use the negative terminal for ground, so could be + l r -
 

rmm200

Senior Member
Apr 15, 2011
1,063
263
0
Bend
One thing for sure, unlike the title of this topic, they are not GPIO pins.

My vote is for stereo audio, ground, and charging. Buy a dock from Asus and see.
 

peterpressure

Member
Jul 23, 2012
18
10
0
One thing for sure, unlike the title of this topic, they are not GPIO pins.

My vote is for stereo audio, ground, and charging. Buy a dock from Asus and see.
If Asus had one available I would buy it!

That said, here is what I found so far...

Top Pin (1): Ground
2: ???
3: ???
4: Data (minus) ???

Tried hot glueing wires into the pogo ports to conduct more tests, but quickly realized it was easier to just pop the back off and wire them directly to the board itself.








 

jb7890

New member
Jul 31, 2012
1
4
0
POGO connection product from ASUS

Here's the product that connects to the pins:

http://www.droid-life.com/2012/07/30/official-nexus-7-accessory-lineup-leaks-pogo-dock-incoming/

JB



So similar to what was found on the Samsung Galaxy Nexus, does anyone know where the source file exists that explains what the 4 POGO pins on the left side of the Nexus 7 are for? I cannot figure them out with my multimeter or oscilloscope.

Samsung Galaxy POGO thread: http://forum.xda-developers.com/showthread.php?t=1614287
File on Samsung Galaxy Nexus was board-tuna-pogo.c but that is obviously not on the Nexus 7 because it is made by Asus and I assume they had a different file.


Close up of the POGO insternals from ifixit.com:
 

peterpressure

Member
Jul 23, 2012
18
10
0
Here's the product that connects to the pins
Well, I am hellbent on beating Asus to the punch!

Protip: apply 5V between your pin 1 and 4 and watch dmesg.
Thank you for this tip! Great help.

I apply GND to pin 1 (top pin) and 5V to pin 4, dmesg (cat /proc/kmsg in Terminal Emulator) says the following upon +5volt insertion.

<4>[ 232.369780] INOK=L
<5>[ 232.370361] smb347_charger: [cable_type_detect] Reg3F : 0x03
<4>[ 232.370850] USBIN=0
<4>[ 232.371113] inok_isr_work_function -


When I remove +5volts it outputs the following:

<4>[ 241.459841] INOK=H
<4>[ 241.460260] ========================================================
<4>[ 241.460933] battery_callback usb_cable_state = 0
<4>[ 241.461296] ========================================================
<4>[ 241.461969] inok_isr_work_function -


But it never starts charging! ARGHHH!!!!
 

peterpressure

Member
Jul 23, 2012
18
10
0
Please do not clutter this thread with anything other than real findings related to the software or hardware involved with the POGO pins.

Ok, small update!

Turn the tablet off, and apply GND to Pin 1 (top pin) and +5Volts to Pin 4 (Bottom pin) and Voila!

IT IS CHARGING via the POGO pins! (but only when turned off)

When I turn the tablet on, it stops charging.

Pictures:

 

clockcycle

Senior Member
Dec 28, 2007
3,666
811
0
Miami, FL
tinkering rox!

Anticipation! I hope you find out the details and are able to make something nice out of it.

My suggestion would be to make something small/slender, that could be adapted to any standard folio type case for the N7 which would allow it to "dock" without taking it out of the casing and use what ever features are available via the POGO.

GL!

-CC
 

mippen

Member
Apr 23, 2007
38
1
0
Is it possible to see if the pins is routed anywhere on PCB?
What kind of hardware (text on chip etc) can be found close to pins?

Is there any direct connection to usb from the pins?
If possible, ohm measure would be interesting.
 

pokey9000

Senior Member
Apr 17, 2007
767
396
0
Austin
Is it possible to see if the pins is routed anywhere on PCB?
What kind of hardware (text on chip etc) can be found close to pins?

Is there any direct connection to usb from the pins?
If possible, ohm measure would be interesting.
The two middle pins don't have any of the voltages you'd need for USB host handshake. In fact they're high impedance at DC. I'm pretty sure they're AC coupled audio out.

---------- Post added at 12:56 PM ---------- Previous post was at 12:51 PM ----------

Ok, small update!

Turn the tablet off, and apply GND to Pin 1 (top pin) and +5Volts to Pin 4 (Bottom pin) and Voila!

IT IS CHARGING via the POGO pins! (but only when turned off)

When I turn the tablet on, it stops charging.
So the dock charging is implemented in the bootloader but not in the kernel. Expect an OS update around the time the dock is released.

BTW Bluetooth V2.0+EDR Audio Communications Module... Sounds fun
 

peterpressure

Member
Jul 23, 2012
18
10
0
My suggestion would be to make something small/slender, that could be adapted to any standard folio type case for the N7 which would allow it to "dock" without taking it out of the casing and use what ever features are available via the POGO.
Exactly!

Is it possible to see if the pins is routed anywhere on PCB?
What kind of hardware (text on chip etc) can be found close to pins?

Is there any direct connection to usb from the pins?
If possible, ohm measure would be interesting.
So this tablet is very easy to open. I kept looking inside but it is a multilayer PCB, so without further disassembly it would be hard to see.
I think we can figure it out via other means.

The two middle pins don't have any of the voltages you'd need for USB host handshake. In fact they're high impedance at DC. I'm pretty sure they're AC coupled audio out.
How can I test this with a sound device?

So the dock charging is implemented in the bootloader but not in the kernel. Expect an OS update around the time the dock is released.
I hope this is not the case! Seems ridiculous to require the user update the OS to use the dock, but who knows.

i got the same thing on the pogo pins only if its turned off but doesnt charge for long
I charged all the way from 0% to 100% via the pogo pins today (with the tablet off). Worked like a charm for me!
 

LouZiffer

Senior Member
Mar 16, 2010
117
43
0
How can I test this with a sound device?
The simplest test, assuming there is no detection going on to enable those pins (they're always enabled): Take any amplifier with a set of speakers, turn its volume all the way down, and turn it off. Run a wire from one of those supposed audio pins to a right or left input on the amp. Run another wire from the output/ground on that terminal to ground. Turn the amp on. Play sound on the tablet and gradually turn the volume up.

If the sound is reproduced by the amp, they're enabled and functional. If not, the tablet may need to be fully docked and receiving power before it enables the audio pins.
 
Last edited:
  • Like
Reactions: Seamus9999