Ventana Audio

The Advanced Linux Sound Architecture (ALSA) system is the current audio driver subsystem in Linux. For details on detecting and configuring ALSA devices see linux/audio

The audio hardware available on Ventana boards:

• ​Freescale SGTL5000 with line level input and output (standard board configuration) or (custom board configuration) headphone level output (custom board configuration) - 45mW max into 16ohme@3.3V load, and mic input
• tda1997x (HDMI Audio in)
• imxhdmisoc (HDMI Audio out)

For information regarding Audio / Video breakout adapters for Ventana see:

• Audio / Video breakout Adapters

Note that by default, Ventana family boards that have analog audio have a default strapping of ​line level audio (both input and output). However, there is an option to load Headphone level output/Mic level input on request. Please contact sales@… if you would like a special built with these loadings.

sgtl5000 (analog audio)

Note that by default, Ventana family boards that have analog audio have a default strapping of ​line level audio (both input and output).

However, there is an option to load Headphone level output and/or Mic level input on request. Please contact sales@… if you would like a special built with these loadings.

Line Level Audio Output

common amixer settings for Analog audio output (make sure to look at /proc/asound/cards to find the correct device number to use with the -c option below):

• Output (Line out)

  # unmute output
  amixer -c 0 sset Lineout on
  # set output level to max
  amixer -c 0 sset PCM 100%
  

• Input (Line in)

  # set capture mux
  amixer -c 0 sset "Capture Mux" LINE_IN
  amixer -c 0 sset "Line In Function" on
  # set capture gain
  amixer -c 0 sset "Capture" 8
  # enable it
  amixer -c 0 sset "Capture" cap
  

Headphone Level Audio Output

If you've ordered a board with HP level audio the following specifications apply:

• sgtl5000 can drive 45mW max into a 16ohm load at 3.3V (53mA)

common amixer settings for headphone level audio:

# Set zero cross detect gain
amixer -c 0 sset Headphone Playback ZC 60%
# unmute output
amixer -c 0 sset Headphone on
# set output level to max
amixer -c 0 sset PCM 100%

In addition, you will also have to make a change to your device tree file in the kernel. Below is a sample patch of what you will have to do (filename depends on product you've ordered)

arch/arm/boot/dts/imx6qdl-gw52xx.dtsi

@@ -109 +109 @@
                audio-codec = <&codec>;
                audio-routing =
                        "LINE_IN", "Line In Jack",
-                       "Line Out Jack", "LINE_OUT";
+                       "Headphone Jack", "HP_OUT";
                mux-int-port = <1>;
                mux-ext-port = <4>;
        };

The defaults for the analog audio (which are found by running 'amixer' with no args) are:

• Output Level (PCM) (0 - 192)
  • Front Left: Playback 192 [100%]
  • Front Right: Playback 192 [100%]
  • disabled
• Capture Mux (MIC_IN or LINE_IN)
  • MIC_IN
• Capture Gain (0-15):
  • Front Left: Capture 5 [33%]
  • Front Right: Capture 6 [40%]
  • disabled

HDMI (digital audio)

The imxhdmisoc audio (output only) device can be used to send digital audio to a connected (and unblanked) HDMI monitor that has speakers.

The tda1997xaudio audio (input only) device (on GW5400 models) can be used to capture digital audio from a connected (and unblanked) HDMI source that streams audio. Note that HDMI audio supports multiple sample-rates and the sample-rate available to capture depends on the incoming source stream. The source stream's audio sample rate can be found via sysfs /sys/bus/i2c/drivers/tda1997x/2-0048/audmode

ALSA utility (alsa-utils package) examples (arecord/aplay)

The alsa-utils package contains the arecord, aplay, amixer applications

aplay:

• playback pre-recorded sound to analog audio device (GW54xx/GW53xx/GW52xx)

  aplay -D sysdefault:CARD=sgtl5000audio /usr/share/sounds/alsa/Front_Center.wav
  

• playback pre-recorded sound to HDMI audio output device

  aplay -D sysdefault:CARD=imxhdmisoc /usr/share/sounds/alsa/Front_Center.wav
  

arecord:

• record 10 seconds of CD quality audio (16bit, 44.1KHz, stereo) from analog audio device to /tmp/foo.wav

  arecord -D sysdefault:CARD=sgtl5000audio -f cd -d 10 -t wav /tmp/foo.wav
  

  • make sure you have specified the capture gain and input device (see above)

Codecs

For Codec support (Encoder / Decoder) details please see:

• Ventana Codecs

Gstreamer examples

For GStreamer information and examples please see:

• GStreamer Audio Wiki Page