I have the Adafruit Microphone working, but I’m not able to get the MVC Volume control to work.
This document describes how it works, but apparently I’m doing something wrong.
Reset Mixer Controls
$alsactl init tegrasndt210ref
Verify that I2S4 is mapped to ADMAIF1
amixer -c tegrasndt210ref sget "ADMAIF1 Mux" amixer -c tegrasndt210ref sget “I2S4 Mux”
Make sure that the 'MVC1 Channels" is set to 0 so that it acts on all 8-channels.
amixer -c tegrasndt210ref sget ‘MVC1 Channels’
I use the following to verify that the audio is working from the Mic.
$ arecord -D hw:tegrasnd210ref,0 -r 44100 -f S32_LE -c 1 -d 10 test.wav
It does, but it’s really quiet.
The following wasn’t successful in connecting up MVC1 to the audio input, and adjusting the volume of it.
$amixer -c tegrasndt210ref cset name=‘I2S4 Mux’ MVC1
$amixer -c tegrasndt210ref cset name=‘MVC1 Mux’ ADMAIF1
$amixer -c tegrasndt210ref cset name=‘MVC1 Vol’ 12000
Where I use the same arecord command line to test it, and the above doesn’t change the volume regardless of whether I use a volume of 0 (max attenuation) or 16,000 (max gain)