Re: em28xx: msi Digivox ATSC board id [0db0:8810]

[Antti Palosaari <crope@iki.fi>]

On 11/29/2012 12:29 AM, Matthew Gyurgyik wrote:
> On 11/28/2012 03:47 PM, Frank Schäfer wrote:
>> Your device seems to use a EM2874 bridge.
> That is what appears on the chip.
>> Any chance to open the device and find out which demodulator it uses ?
> To my surprise it was easier to open than expected.
>
> I think this is the demodulator:
>
> 7th Generation
> VS8/QAM Receiver
> LG
> LGDT3305
> 1211
> PGU419.00A
>
> I took some pictures (of the entire card):
> http://pyther.net/a/digivox_atsc/ (SideA_1.jpg, SideA_2.jpg,
> SideB_1.jpg, SideB_2.jpg)
>> Are you able to compile a kernel on your own to test patches ? It's not
>> that hard... ;)
> I sure can! I've done some kernel bisects in the past.

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.

regards
Antti

-- 
http://palosaari.fi/