I want to use ST MEMS microphone (MP45DT02) on STM324xG_EVAL board, I used an extension board and attached the digital microphone to the board. It works very well when I use 16 KHz for AudioFreq, I mean:
#define DEFAULT_AUDIO_IN_FREQ I2S_AUDIOFREQ_16K
But I want to have 8 KHz frequency for my final audio output and when I use I2S_AUDIOFREQ_8K in my code, the Input clock frequency for microphone become about 500 KHz and so because of microphone ‘s Input clock frequency characteristic (1-3.25MHz),it doesn’t work.
How can I have 8 KHz for my final audio output?
The wondering matter is that Discovery Board works with 500 KHz for microphone ‘s Input clock frequency and I know the frequency of the PDM data output from the microphone (which is the clock input to the
microphone) must be a multiple of the final audio output needed from the system.