Re: custom audio card on beaglebone

[anish singh <anish198519851985@xxxxxxxxx>]

On Wed, Jan 25, 2017 at 2:30 AM, <crazyiop@xxxxxxxxx> wrote:

Hi Anish,

thanks for giving me some thougt.
Here is what I found:

On Sun, Jan 22, 2017 at 03:47:54PM -0800, anish singh wrote:
> On Sun, Jan 22, 2017 at 1:38 PM, jo <crazyiop@xxxxxxxxx> wrote:
>

> > root@beaglebone:~# aplay -v Pom\ Pom.wav
> > Playing WAVE 'Pom Pom.wav' : Signed 32 bit Little Endian, Rate 44100 Hz,
> > Stereo
> > ALSA <-> PulseAudio PCM I/O Plugin
> > Its setup is:
> >   stream       : PLAYBACK
> >   access       : RW_INTERLEAVED
> >   format       : S32_LE
> >   subformat    : STD
> >   channels     : 2
> >   rate         : 44100
> >   exact rate   : 44100 (44100/1)
> >   msbits       : 32
> >   buffer_size  : 22050
> >   period_size  : 5512
> >   period_time  : 125000
> >   tstamp_mode  : NONE
> >   period_step  : 1
> >   avail_min    : 5512
> >   period_event : 0
> >   start_threshold  : 22050
> >   stop_threshold   : 22050
> >   silence_threshold: 0
> >   silence_size : 0
> >   boundary     : 1445068800
> >
> > #nothing play and the above stay displayed -as is- until I ctrl-c
> >
>
> Possible that you have not turned on the mixer controls i.e.
> enabling the volume?
>
> Check sw_ptr and hw_ptr and see if those are increasing or not?
>
> Probe the I2S lines and see if there is any data?
>
>

So first, the above command in fact do finish after the length of the file (I
thought I took a much smaller test sample..)

The mixer control were all on and volume to the max.
I don't have a scope, but you made me realize that I'm clueless in front
of my problem without one... So I finnaly found an access to one. The measure
show that the input clock of the pll (mclk) is just non-existant.
I now know what to look for.

I tried to find a reference to those sw_ptr and hw_ptr somewhere,
without success, what are they and where can I find/probe them ?

# cat /proc/asound/card0/pcm0p/sub0/status
state: RUNNING
owner_pid   : 1440
trigger_time: 16024.849105290
tstamp      : 16175.605386326
delay       : 768
avail       : 1280
avail_max   : 2048
-----
hw_ptr      : 7236608
appl_ptr    : 7237376
 

Thanks!!
Jonathan.

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