Dock Pinout

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DayBlur

New member
Feb 13, 2010
3
0
My results

I plan on making a charging-only dock as well. Here's what I measured on the Google dock pins (my numbering).

1 - 5V
2 - CTL

(mic port)
3 - GND

There's about 5.2V (no load) at the dock between pins 1 and 3. The dock also measures 10kohm between pins 2 and 3. It seems pretty straight forward, and there don't seem to be any other interesting or unexpected voltage or resistance values between other pin combinations.

The phone does start charging fine when applying an external 5V on pins 1 and 3, but I have been unable to force it into the dock mode. I have connected an external 10k resistor between pins 2 and 3 both with and without power applied to the charging pins with no luck. Any ideas? I just played with it for a few minutes, but I'll post if I figure anything out when I get back to it.
 
D

diversificationied

Guest
When you manually put the charge on, does that affect the bluetooth settings?

I'm thinking maybe when it has a charge through the pins it activates bluetooth so it can pair with the docks bluetooth, and that activates the dock mode?
 

Red MacGregor

Senior Member
Feb 12, 2010
91
0
nexus dock

is pretty damn cool...

when i get a chance this weekend, i'm going to hook up a meter to the pin-outs and see what it's doing with the 3rd pin to force clock mode
 

dhendrix11

Senior Member
Aug 19, 2009
52
1
Ok so after reading some dock threads, I decided to contribute something useful to the discussion by taking my dock apart. Unfortunately, what I've found is bad news for a simple DIY dock. The middle pin looks to be a bit pattern toggled by the dock upon insertion of the phone.

P3040008.JPG


P3040023.JPG


P3040028.JPG


The bottom trace is the full signal toggling. The top trace is zoomed in on the left side of the bottom trace.
 

DayBlur

New member
Feb 13, 2010
3
0
Awesome, thanks for the info. I haven't been able to get back to additional testing or taking mine apart yet.

1. How hard was the dock to take apart? Did it just require peeling off the rubber bottom and removing screws, or something more destructive?

2. I was wondering if you could post or email a higher resolution image of your annotated board layout - I couldn't quite make out some of the text in the upper left.

3. Does that bit pattern ever change, and is it bi-directional? That delay in the middle makes it look to me like a challenge-response. My random guess is that the phone sends that first pattern when it gets power on the dock pins, and then the dock (if connected) responds with some kind of identifier (home/car/etc). It should be pretty easy to replicate such a static pattern/response with a simple microcontroller...

Thanks,
James
 

dhendrix11

Senior Member
Aug 19, 2009
52
1
Awesome, thanks for the info. I haven't been able to get back to additional testing or taking mine apart yet.

1. How hard was the dock to take apart? Did it just require peeling off the rubber bottom and removing screws, or something more destructive?

2. I was wondering if you could post or email a higher resolution image of your annotated board layout - I couldn't quite make out some of the text in the upper left.

3. Does that bit pattern ever change, and is it bi-directional? That delay in the middle makes it look to me like a challenge-response. My random guess is that the phone sends that first pattern when it gets power on the dock pins, and then the dock (if connected) responds with some kind of identifier (home/car/etc). It should be pretty easy to replicate such a static pattern/response with a simple microcontroller...

Thanks,
James

1. It was very easy to take the dock apart. Remove 4 screws under the rubber bottom and you get to the PCB. Remove 1 screw to take the pcb out. You can disconnect the wire harness that connects the PCB to the 3 dock pins very easily.

2. Original high res photo is in the attached zip file.

3. I hooked 5V between the pwr and gnd pins on the phone without the dock, and a 10k resistor from the middle pin to GND. Upon connecting the 5V, the phone outputs 9 pulses @ 25Hz. However, that doesn't really jive with the timing from my previous scope captures, so maybe I wasn't looking at the whole picture connected through the dock. I don't feel like taking my dock apart again tonight, but I'll see about some further investigation this weekend.

2010-03-04%2022.14.03.jpg
 

Attachments

  • P3040023.zip
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T

tiberiumx

Guest
Anyone have a logic analyzer? The transferred data could be captured and decoded. It probably wouldn't be too tough to code up a microcontroller to interact with it for a DIY dock if we knew what it was saying.

If anyone wants to send me a dock, I could hook it up to mine and try to get a binary dump. :)
 
Last edited:

rotohammer

Senior Member
Jan 2, 2007
1,386
1,066
New Jersey
The previous image of the waveform looks like it could be a "tone burst", or being square wave, its just 10101010101010101010.

It could be used to prevent bounce using a simple circuit on the recieving side like this:

Code:
                                               ________
in                                    out  ____|      |_______
>------||--+----/\/\/\/\------>
           |
           +---||----+
              +      |
                     |
                   GND
 
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dhendrix11

Senior Member
Aug 19, 2009
52
1
Here are some better scope captures. The 25Hz pulse train output from the phone only occurs if it's not connected to a dock. If there's a dock present, you get the bit patterns from my original post.

Next I have to figure out if this is bi-directional.

Connect%205v%20to%20Phone.jpg


Both%20Pulses.jpg


Pulse%201.jpg


Pulse%202.jpg
 

rashid11

Senior Member
Mar 4, 2010
144
11
N1 is prolly sending the bursts every few secs, so that when it is placed into a dock, the dock detects presence of N1.

This is where it could get interesting. Since N1 communicates to the dock via BT, it might need to know the dock's BT Device ID (MAC-address-like) - so that it doesn't end up pairing with a different dock that your coworker has in an adjacent cube . So may be what the dock sends back after detecting the N1 is in fact its BT ID ?
 

brotbuexe

Senior Member
Apr 16, 2009
493
130