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Fun with resistors (home/car dock mode + more)

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By TheBeano, Senior Member on 26th October 2010, 09:39 PM
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20th January 2011, 10:47 AM |#51  
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Quote:
Originally Posted by jonagpa

I am not sure why you wanted me to do this, I guess I could post the result here but I am not sure is it may contain something I should not share. Let me know what you think, thanks

Search for FSA9480, these are messages from the USB switch chip that detects resistors on the ID pin and connects the USB socket to various things.

If you have rooted the phone you can do "su" from the adb shell prompt and then "dmesg -c" to clear the log, then plug the USB plug in.
20th January 2011, 05:54 PM |#52  
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Quote:
Originally Posted by TheBeano

Search for FSA9480, these are messages from the USB switch chip that detects resistors on the ID pin and connects the USB socket to various things.

If you have rooted the phone you can do "su" from the adb shell prompt and then "dmesg -c" to clear the log, then plug the USB plug in.

Did that and this is what I found after searching for FSA9480

these 2 I found together
<4>[56279.087054] [FSA9480]FSA INTR = dev1 : 0x4, dev2 : 0x0, Attach : 0x1
<4>[56279.087068] [FSA9480_Enable_AP_USB] Enable AP USB

THis one I found further down
<7>[56279.120401] fsa9480 I2C Codec 7-0025: legacy resume

how should I proceed from here?
21st January 2011, 04:17 AM |#53  
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Quote:
Originally Posted by drhowardfine

FWIW, I tried the Home Dock mode with the 133K resistor across pins 4 & 5.

It worked, and launched the Desk Home App.

I looked at the USB data lines with a scope, hoping to find L & R audio on them, but NO joy.

So it appears all the dock will do is charge the phone and start the Desk Home App. I'm surprised Samsung made no provision for audio out for a simple speaker dock. (Video would have been nice too, but I don't see how they'd do it with only 2 available pins)

I assume the car dock mode will have the same results - only charge and launch an app. Maybe I'll get a chance to try next week.

There are some Captivate ROMs that let the Captivate play audio out through the dock output. It is highly dependent on the ROM though.

If we could probe the traces on the dock's PCB itself, that would be a better shot at learning more about the switching process.
21st January 2011, 07:45 AM |#54  
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Quote:
Originally Posted by jonagpa

Did that and this is what I found after searching for FSA9480

these 2 I found together
<4>[56279.087054] [FSA9480]FSA INTR = dev1 : 0x4, dev2 : 0x0, Attach : 0x1
<4>[56279.087068] [FSA9480_Enable_AP_USB] Enable AP USB

THis one I found further down
<7>[56279.120401] fsa9480 I2C Codec 7-0025: legacy resume

how should I proceed from here?

Anyone else know what I should do next?
21st January 2011, 10:59 AM |#55  
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Quote:
Originally Posted by jonagpa

Did that and this is what I found after searching for FSA9480

these 2 I found together
<4>[56279.087054] [FSA9480]FSA INTR = dev1 : 0x4, dev2 : 0x0, Attach : 0x1
<4>[56279.087068] [FSA9480_Enable_AP_USB] Enable AP USB

THis one I found further down
<7>[56279.120401] fsa9480 I2C Codec 7-0025: legacy resume

how should I proceed from here?

These are the values that you get when you plug in USB without a resistor (dev1=0x4, dev2=0x0), so it is not detecting a resistor on the ID pin. Something could be wrong with your plug wiring.
21st January 2011, 07:53 PM |#56  
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Quote:
Originally Posted by TheBeano

These are the values that you get when you plug in USB without a resistor (dev1=0x4, dev2=0x0), so it is not detecting a resistor on the ID pin. Something could be wrong with your plug wiring.

well, I guess I have been doing this all wrong. I was under the impression that by just putting a resistor on pin 4 and 5 the app would be called. i am not actually plugged into anything while I am trying resistors. So I need to build that board you had in one of your pics with the variable resistor?
22nd January 2011, 12:14 AM |#57  
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Quote:
Originally Posted by jonagpa

well, I guess I have been doing this all wrong. I was under the impression that by just putting a resistor on pin 4 and 5 the app would be called. i am not actually plugged into anything while I am trying resistors. So I need to build that board you had in one of your pics with the variable resistor?

If you're getting that event in the log without anything else connected to the plug other than the resistors then you are on the right pins, but either the resistor value is wrong, the connection isn't steady or you aren't holding the resistor onto the pins for long enough (needs at least two seconds of solid contact). It should work fine without anything else connected to the plug other than the resistor(s). It's definitely easier to experiment with the Sparkfun breakout board and a variable resistor and soldered or breadboard connections.
23rd January 2011, 02:49 AM |#58  
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Some notes about the UART:

The UART device is /dev/ttySAC2 but you need to create a device node for it as described in this file from the kernel source:
Documentation/arm/Samsung-S3C24XX/Overview.txt

So use this command (root required):
Code:
mknod ttySAC2 c 204 66
The UART is switched between the MODEM (radio) and PDA (CPU) by the device /sys/devices/virtual/sec/switch/uart_sel

You can see what the current state is with this command:
Code:
cat /sys/class/sec/switch/uart_sel
    [UART Switch] Current UART owner = PDA
You can change the state with:
Code:
   echo PDA> /sys/class/sec/switch/uart_sel
or
   echo MODEM> /sys/class/sec/switch/uart_sel
You can tell when it's connected to MODEM because it will respond to AT commands, e.g.
Code:
ATI0
 Manufacturer: SAMSUNG

 Model: I9000

 Revision: I9000XXJPP

 IMEI: ***************
The baud rate is set to 115200 at boot time, I don't know how to change it as yet.
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23rd January 2011, 08:01 PM |#59  
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will the Home Dock mode work with 1K ?
31st January 2011, 07:55 PM |#60  
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going a bit offtopic on this q.

Is this 301k resistor samsung specific, or is it in any way built into the base of android-phones and could work with htc-phones aswell? have anyone tried it?

asking becuase i only find posts about this in samsung-parts of the forum, and it could solve a few bricked htc-phones across the world. not mine though, it isnt bricked...yet.
1st February 2011, 04:06 AM |#61  
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Quote:
Originally Posted by robe42

Is this 301k resistor samsung specific, or is it in any way built into the base of android-phones and could work with htc-phones aswell? have anyone tried it?

It is specific to Samsung. You could look through the device driver source code of other phones and look for a similar switching arrangement though, but I imagine the guys that did the bootloader unlock for HTC have done that already.
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