Thread (4 messages) 4 messages, 2 authors, 2017-01-25

custom audio card on beaglebone

From: crazyiop at gmail.com <hidden>
Date: 2017-01-25 10:30:30

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 [off-list ref] wrote:
quoted
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 ?

Thanks!!
Jonathan.
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