[clug] Panasonic TX37LZD81 source code

[David Tulloh]

>From my fairly limited experience they have always stashed a serial port
of some kind in a linux embedded device for development but hide it from
the outside.  It's the same PCB though so it's there... somewhere.

The port could be disguised as another plug type, like hdmi, this would
then run into a custom debugging breakout box which provides the serial
line along with other signals, probe points and logic analyser headers
etc.  If this is the case it's probably fairly easy to isolate the
serial lines.

Another option is that they haven't fitted the plug to the board, so you
would look for a nice clear area on the PCB with fairly large exposed
pads (probably 4) but no component, often labelled J# or P# (# being a
number).

If the PCB is fairly large I'd try looking near the central processor. 
This is often the biggest chip and probably has nearby flash chips.


Once you get a serial port it probably will be running a serial
console.  The devices I've played with are designed to be developed off
a NFS share, the flash chips don't have fancy load balancing hardware. 
So if you mess around in the boot loader you can get it to run off a
tftp and nfs server on your network.  Then you can mount the flash disk
and get at it's contents.

I wouldn't expect their cooperation in hacking on it, I'd also expect
all the interesting stuff (screen and tuner interaction) to be closed
source binaries running on the system.


David

Paul wrote:
>  we mentioned this at a CLUG meeting earlier this year, and I think
> the other question was how to interface to the code, ie did the TV
> have a secret USB or serial port somewhere?
> and we where trying to source the service manual to get more info..
>
> Paul
>
> On 3/03/2009 2:29 PM, Chris Smart wrote:
>> I know a few people have some similar TVs, not sure if it's this one
>> though. Anyway, here's a link to a post about the source code.
>> "http://jguk.org/2009/03/panasonic-tx37lzd81-tv-runs-gnulinux.html"
>>
>> And the link to the source:
>> "http://www.am-linux.jp/dl/EUIDTV6/"
>>
>> -c
>