On 01/27/2014 08:06 PM, Jean-Francois Moine wrote:
On Mon, 27 Jan 2014 18:17:54 +0200
Jyri Sarha <jsarha@xxxxxx> wrote:
Support for S16_LE could maybe be added if the tda998x specific codec
would fiddle with CTS_N predivider-setting (K select) according to the
used sample width. But it appears Cobox plays all the sample formats
fine without this change, so the question is if playing around with
CTS_N predivider would break already working support there (something to
be tested).
Jyri,
Setting
cts_n = CTS_N_M(3) | CTS_N_K(1);
instead of K(3) in the I2S sequence of tda998x_configure_audio() in the
tda998x driver works fine for me with S16_LE and S24_LE.
Does this solve your problem?
With that setting S16_LE works, but S32_LE does not. S24_LE does not
really work at all on BBB, or it works but because the 8 most
significant bits are zero the audio output is attenuated by 48 dB.
On the other hand S24_3LE does work, but then the problem is the clock
rate support. On BBB the McASP IP is the bit clock master and provides
the bit clock by simple divider from 24.576MHz oscillator. With 24 bit
samples neither 44100 or 48000Hz sample rate can be supported (on the
other hand 32kHz could be supported 24576000 % (24*2*32000) = 0).
The BBB HW price has squeezed so low that it can only implement the most
basic use cases.
I would suggest to leave the CTS_N_K to the current setting (3), unless
we can change the CTS_N_K on the fly according to the used sample format.
Best regards,
Jyri
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