Reverse engineering the Blu Studio 5.3 dock port

Okay. It seems that Blu Products isn't going to explain anything about the dock port on their Studio 5.3, so I am embarking on a project to reverse engineer it. I'll update my progress here.

Pictures of the dock port:






Pictures of the plug that fits it. It's the same 30-pin plug as found on the iPod and a bunch of other devices.







(Last 3 images from https://www.sparkfun.com/products/8295)


What I just ordered to work on this project:




(Again from https://www.sparkfun.com/products/8295)


Here's what I've figured out so far.

The cable from my iPod Nano 6th gen has pins 1, 15, 16, 23, 25 and 27. All others are missing. I haven't had time to analyze it all yet, but according to allpinouts.org, 1 is a ground, 15 and 16 are grounds and are tied together (internally on the iPod motherboard), 23 is USB +5v, and 25/27 are USB Data+/- OR, alternately, they are resistor-to-ground value-based signals.

My theory so far is that there is some internal resistance between the pins in this cable and other pins or ground; because plugging just the cable in--with it not being plugged into the USB port--disables the Blu's touchscreen and automatic screen rotation features and locks the screen in whatever position it's in when you plug in the cable. (Although interestingly, if you plug it in in landscape mode, you can use the screen rotation lock hardware button to put it back to portrait mode.) Plugging the other end of the cable into a USB port brings up the Recent Apps display (the thing that comes up when you hold the touchscreen home button down) and the phone says it's charging, but the touchscreen is still disabled. Not sure if it's actually charging or not; I'm gonna leave it plugged in for awhile and see. The phone does not show up as a new USB device when this (iPod) cable is plugged into the dock port.

Once I get the breakout board I'm gonna take the phone apart and see if I can trace where the pins in this dock port go. I'm also going to wire up a USB cable to the breakout board and see if I can get the phone to enumerate.

Hopefully I never toast my phone.

Edit for more pics from teardown:











Notice that this ribbon cable is 3 layers; those are little pieces of a paperclip holding them apart to show the layers.

Ok here's what I've figured out so far.

1. Make sure if you take your phone apart that you reconnect all the connectors inside the phone, or else you'll spend an hour trying to figure out why the dock port won't work at all before realizing what you did.

2. Onward to real research, here's what's been found so far.

Connecting pin 15 to 16 disables the touchscreen, but there is a threshold that must be met that I haven't found yet. If the 2 pins are directly tied together the touchscreen is disabled, and if there's a 3k resistor between them it is, too. But if there's a 100k resistor inline it doesn't disable the touchscreen.

Pin 1 appears to be a ground pin.
Pin 16 is USB ground
Pin 23 is USB +5 volts
It DOES charge when just Pins 16 and 23 are connected. My next step is to find which pins are the USB Data +/-. As can be seen below, it's non-standard.

Connecting Pin 27 to ground presses the hardware multifunction button (bottom middle of the front panel)
Pin 6 to ground presses hardware power key
Pin 29 to ground presses hardware volume down key
Pin 28 to ground is an oddball. Connecting it to ground through a 10k resistor seems to start the music player AND press the hardware volume up key
Connecting pin 9 to ground with a resistor less than 4k causes a white screen followed by a black screen and the phone freezing until the battery is removed.

Audio
Pin 3 - Audio Ground
Pin 4 - Audio Right
Pin 5 - Audio Left
The audio pins appear to be connected to the same lines as the headphone jack, only they don't have the hardware external speaker disable (or if they do I haven't found it yet). Apparently, the headphone hardware triggers a software signal of some kind that disables the external speaker. I confirmed that this is the case by plugging in a set of headphones, in which case these lines still give the audio output but the external speaker is disabled. Apparently this is something that can be controlled from within Android, because there were some bug reports awhile back about the external speaker not disabling when headphones were plugged in. So we need to find (or maybe someone can write?) an app that does nothing but disable the external speaker while leaving the headphone line active.

No luck yet on getting USB working. Still hoping someone here can help me out with knowing how to monitor what's going on by using adb?

Its seems like its a docking port for a keyboard. I found this for Pearl Simvalley SPX-5 site found at http://www.pearl.de/a-PX3502-4072.shtml.

Just got the PodBreakout board. To the soldering station I go. Send good karma my way.

I took the entire thing apart. Everything is under full-board metal shields as can be seen from the recent post-op pic. (You can also see the breakout board.) My phone still works, so I'm not prepared to go pulling the shields off just to see what's under them. I think that the only things would be the MediaTek CPU and some RAM and Flash chips anyway. Everything else is pretty tightly integrated.

Puppeto if you get ahold of one of those keyboards please keep us updated.

Behold the wonders of voiding your warranty:

ROM for texet 5200

wesblood said:

Hey you all can anyone please supply me with a link to obtain the actual stock rom for the blue studio 5.3 or even a custom rom would be of great help thanking you in advance

Sent from my BLU Studio 5.3 using xda app-developers app

Click to expand...

Click to collapse

There is a Russian device which seems to be identical to Blu Studio and is called Texet 5200 (accordng to some of the threads here in xda-developers).
There is a site for the device, I found the ROM for download easilly
XDA won't let me post URL cause I didn't write enogh posts yet ,
Just use google translate to browse through "texet dot ru". If you are having difficulty PM me)
There seem to be two ROM version, the original and a newer, lighter one from 28.08.2012.
I did not try it, use at your own risk.
If you do, please let us know how it went.
If you look in xda forums there is someone here that claims to have already installed those ROMs.
Good luck, Hope this helps