@Andrew-Naumenko
true I had seen it. from that picture it is sure it is 16 bits per channel i2s (into 32 bit bclk total sample) wordclock.
but the fact you need to turn down volume so much is all the more strange knowing that both your omega2 and tda dac are EXACTLY same philips i2s mode format (and both 16 bits only).

@Denis-Mikhalsky
also you need to configure your pcm5102 to i2s mode format (not LJ) on a first trial . it should work perfectly.

Hi all
Does anyone know if the current driver in use stock in omega2 use LeftJustified or the RightJ or the philips format i2s (one bitclock delayed) i2s format ?
also it is 16 bit data per channel and 32 bit total word bitclock I think : meaning we need to use either simple 16 bit only dacs or else very wide accepting comptability multi-formats allowing (extensive format input accepting) dacs.
still it is a nice evolution from some weeks ago when i2s/sound was not featured at all.

In fact Andrew I suspect from your overdrive distortion and volume symptoms (without all checking the mt7688 doc and register) omega2 driver is probably left justified format when your dac tda1543 only strictly accept philips justified i2s (meaning 1 bck delayed msb left justified) . that would mean an error on your dac ms bit understanding. meaning it starts seemingly to correctly work only when volume is grossly reduced.

@Denis-Mikhalsky
I use b177 I get some correct sound (not perfect due to some incompatibilities with my standart dac) but that should work b177 is not the problem look else for the cause .

I think I got an idea for you to check later : pcm 5102 has a format pin for hardware configuring to adapt to the received i2s mode format. maybe you could change from one to another between LJustified and i2s justified but I do not think that is the problem of lack of sound (only proper decoding of bits without overdrive/distortions).

you need to update (oupgrade command) to late firmwares and activate (command line) i2s mode for the gpio . you need to use the 3 mentioned pins that are specific on the onion boards . there is a 2 bulletarticle tutorial.

http://community.onion.io/topic/1761/resolved-attaching-pcm5102-to-omega2-i2s

tell us your progress and trials.

@luz
Hi do you know any quite simple way so as to use a 24bit data out i2s driver (seems that the a max... .c offer that mode : s24) : using any recent omega2 firmware (mainly your works) but getting that option mode to activate s24 instead of 16bit data format ?
stream_name = "HiFi Playback",
SNDRV_PCM_FMTBIT_S24
SNDRV_PCM_FMTBIT_S32,

thanks a lot for all

Hi all,
I am inquiring about a maximum digital out volume level creating the distortion (overdrive) as the possible problem cause. amixer and alsamixer being provided I used them to see and reduce all playback devices I could find just to try easy fixes and inquiring tools. amixer itself verbose playing : aplay -v -D hw:0 -f cd /dev/zero seems to send data rawinterleaved S16LE as we need but as of now I had not the opportunity to test a small .wav so as to hear result so if anyone is interested please do test this command playing a wav file : aplay xxfile.wav -v -D hw:0 -f cd
is there any volume control register in MT7688 I don't think ? MUCH unfortunately -g parameter is not featured anymore in mpg123 which would have been heaven... note though that the key press of - and prolonged pressing reduces volume gradually (on other than omega2 devices) so if any has a trick to : there is still some volume command in mpg123.
actually I do not know if is only a overvolume distortion problem or if it also is a problem of unsigned format which should be signed...
to help answer that question installing a mpg321 package could provide to the ones's interested the software volume control (gain) as it seems to offer (and better fixedpoint processing efficiency).
thanks

Yes about sign : drivers which were used as bases of our omega simpleaudio driver seemed S16 as normal but if Andrew is sure it actually sends unsigned then that is the problem :
If the maxxxxxx driver actually uses the unsigned (weird unstandart and rare) 16bit format then we need to switch our firmware to builds using an asoc/alsa wm8960 or pcm5102 or whatever else is available as nearly ALL OTHER i2s drivers would provide us the usual/standart (i2s meaning signed) our DAC chips need.

"MCK lack" subject is not the problem here because I also use a i2s DAC chip that features an MCK generation builtin because MT7688 chip does not have any MCKout.

These 2 matter would make me much regret the former ar9331 soc chip...

happened recently to me too : constant slow flashing led and impossible to "establish connection" for the terminal tool only. otherwise the rest seems to work correctly. I do not know if problem will persist or was momentary. I would not reset it only for what is probably a momentary problem.

@luz
hi I understand most what is inside the MAX audio driver it is just I do not know how to mod my current firmware omega to put in the feature that would make it suiting all standart i2s dacs scenario.