custom audio card on beaglebone

anish singh anish198519851985 at gmail.com
Wed Jan 25 18:35:44 EST 2017


On Wed, Jan 25, 2017 at 2:30 AM, <crazyiop at gmail.com> 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 at gmail.com> wrote:
> >
> > > root at 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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