Entrada analógica

Se ha observado una sensibilidad escasa en la entrada analógica de esta tarjeta, lo que supone que algunas fuentes pueden tener un nivel muy bajo.

Podremos 'amplificar' la señal obtenida en system:capture, ver AQUI

Audioinjector I2S sound card by Flatmax.org

Manual setup method

http://www.flatmax.org/phpbb/viewtopic.php?f=5&t=3

• Ensure you have the latest kernel : sudo rpi-update

/boot/config.txt

• Make sure the default audio device tree is not loaded for PWM output (/boot/config.txt), this is because it uses the same I2S bus. (Comment out dtparam=audio=on)

• Make sure the Audio Injector device tree is loaded at boot time : dtoverlay=audioinjector-wm8731-audio

Reboot to force the correct device tree to load.

Service files:

alsactl --file /usr/share/doc/audioInjector/asound.state.RCA.thru.test restore

alsactl --file /usr/share/doc/audioInjector/asound.state.MIC.thru.test restore

$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: audioinjectorpi [audioinjector-pi-soundcard], device 0: AudioInjector audio wm8731-hifi-0 []
  Subdevices: 0/1
  Subdevice #0: subdevice #0

Ajustes de amixer ALSA:

Aqui aparecen algunas referencias a este tipo de controles amixer, aunque nuestra tarjeta tiene otro chip WM8731 (snd_soc_wm8731) https://wiki.analog.com/resources/tools-software/linux-drivers/sound/ssm2602#supported_devices

Yo los tengo así:

AJUSTE:                                    OBSERVACIONES:
'Master Playback ZC Switch'=off,off        ¿¿¿???
'Master Playback Volume'=121,121           0 dB
'Line Capture Switch'=on,on
'Mic Boost Volume'=0
'Mic Capture Switch'=off
'ADC High Pass Filter Switch'=off          subsonic?
'Capture Volume'=23,23                     0 dB
'Playback Deemphasis Switch'=off
'Output Mixer HiFi Playback Switch'=on     pone el DAC en la salida 
'Output Mixer Line Bypass Switch'=off      es un LineIn monitor 
'Output Mixer Mic Sidetone Switch'=off     ¿¿??
'Sidetone Playback Volume'=0               ¿¿??
'Store DC Offset Switch'=off               ¿¿??

firtro@rpi2fir:~ $ amixer -Dhw:audioinjectorpi scontents
Simple mixer control 'Master',0
  Capabilities: pvolume
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 127
  Mono:
  Front Left: Playback 121 [95%] [0.00dB]
  Front Right: Playback 121 [95%] [0.00dB]
Simple mixer control 'Master Playback ZC',0
  Capabilities: pswitch
  Playback channels: Front Left - Front Right
  Mono:
  Front Left: Playback [off]
  Front Right: Playback [off]
Simple mixer control 'Sidetone',0
  Capabilities: pvolume pvolume-joined
  Playback channels: Mono
  Limits: Playback 0 - 3
  Mono: Playback 0 [0%] [-15.00dB]
Simple mixer control 'Line',0
  Capabilities: cswitch
  Capture channels: Front Left - Front Right
  Front Left: Capture [on]
  Front Right: Capture [on]
Simple mixer control 'Mic',0
  Capabilities: cswitch cswitch-joined
  Capture channels: Mono
  Mono: Capture [off]
Simple mixer control 'Mic Boost',0
  Capabilities: volume volume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 1
  Mono: 0 [0%] [0.00dB]
Simple mixer control 'Playback Deemphasis',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]
Simple mixer control 'Capture',0
  Capabilities: cvolume
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 31
  Front Left: Capture 23 [74%] [0.00dB]
  Front Right: Capture 23 [74%] [0.00dB]
Simple mixer control 'ADC High Pass Filter',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]
Simple mixer control 'Input Mux',0
  Capabilities: enum
  Items: 'Line In' 'Mic'
  Item0: 'Line In'
Simple mixer control 'Output Mixer HiFi',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [on]
Simple mixer control 'Output Mixer Line Bypass',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]
Simple mixer control 'Output Mixer Mic Sidetone',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]
Simple mixer control 'Store DC Offset',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]
firtro@rpi2fir:~ $