I am currently working on an audio application on STM32F7-discovery.
The example application is recording in stereo from the 2 MEMS microphones regardless of the parameters sent to :
I am now using my own application , but the behavior is the same , always stereo.
I suspected that it was because the codec initialization code in wm8994.c was turning on both channels when the input device specified is : INPUT_DEVICE_DIGITAL_MICROPHONE_2
So i changed the initialization of INPUT_DEVICE_DIGITAL_MICROPHONE_2 to only initialize the right channel and disable the left one In order to get a mono output from the wm8994.
I have indeed the left channel constantly at 0 so it is disabled , but the samples are still received.
I would like to receive only the RIGHT channel samples, is this even possible ? I assumed that it is but maybe not..
I don't know if this is a DMA configuration error or another setting that i cannot find in the wm8994 datasheet.
If i understand correctly the two MEMS microphones share the same clock and data line the wm8994 is reading at both rising and falling edge on the data line , where each microphone alternately "send" it's PDM sample.
I looked for a way to read only on one edge on the wm8994 but without success so far.
My apologies if i missed something obvious, for now I only take the odd samples from the received buffer but i believe that a much cleaner solution is possible ?
Thanks in advance for any help !