On 11/29/2012 09:28 PM, Frank Schäfer wrote:
Am 29.11.2012 03:15, schrieb Antti Palosaari:
On 11/29/2012 04:05 AM, Matthew Gyurgyik wrote:
On 11/28/2012 05:55 PM, Antti Palosaari wrote:
Very, very, good pics and sniffs!!
From the sniff you could see I2C addresses
50 (a0 >> 1) eeprom
0e (1c >> 1) demod
60 (c0 >> 1) tuner
EM2874, USB-bridge, clocked at 12MHz, crystal on other side of PCB.
There is also 32k serial eeprom for EM2874. This large serial eeprom
means (very likely) it uses custom firmware which is downloaded from
the eeprom.
LGDT3305, demodulator, clocked at 25MHz. Serial TS used between EM2874
and LGDT3305.
TDA18271HDC2 is tuner, clocked at 16MHz. Traditional IF used between
tuner and demod.
IR receiver is near antenna, which is a little bit long wires to
connect to the EM2874, looks weird but no harm.
Main GPIO sequence is that one:
000255: 000006 ms 000990 ms c0 00 00 00 80 00 01 00 <<< ff
000256: 000004 ms 000994 ms 40 00 00 00 80 00 01 00 >>> fe
000257: 000006 ms 001000 ms c0 00 00 00 80 00 01 00 <<< fe
000258: 000004 ms 001004 ms 40 00 00 00 80 00 01 00 >>> be
000259: 000139 ms 001143 ms c0 00 00 00 80 00 01 00 <<< be
000260: 000005 ms 001148 ms 40 00 00 00 80 00 01 00 >>> fe
There is some more GPIOs later, just test with trial and error to find
out all GPIOs.
Making that device working should be quite easy! There is a little
change for proprietary firmware for EM2874 which does some nasty
things, but that is very very unlikely.
Do we know any devices with a "real" proprietary firmware ??
I'm not talking about custom USB ID, endpoint configuration and minor
stuff like this...
I am not aware any such em28xx device. Default firmware seems to be just
enough for most cases. Normally there is 2k eeprom which is used to
store some basic configuration information, USB IDs and some other
properties.
I don't know how much expensive 32k eeprom is than 2k eeprom, but one
possibility is also it is just used because they have had a lot of
spare 32k eeproms to waste...
regards
Antti
Thanks for the information. That is way over my head. Is there same
basic reading someone could recommend so I can start to understand the
basics of all this?
In the mean time, I'm willing to do any testing necessary.
Maybe I could give hour or two for that if you could make tests I ask?
If someone else would like to hack with it, I am very happy too. Frank?
Seems like we have all we need, right ? A TDA18271 driver seems to be in
place, what about the LGDT3305 demodulator ?
I can try to put the puzzle together, but not before weekend.
Matthew, stay tuned but be patient. ;)
Good!
Yes, there is existing drivers for all the used chips. Just make correct
device profile (and hope there is no any nasty custom fw things).
regards
Antti
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http://palosaari.fi/
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