Customer modified the definition of OSR in fsl_micfil.h from 0 to 8 as below to let PDM clock worked at 3.072MHz when recording by 48KHz sampling rate.
#define MICFIL_CTRL2_OSR_DEFAULT (8 << MICFIL_CTRL2_CICOSR_SHIFT)
Customer also set “MICFIL Quality Select” to 1 and all “CH? Gain” to 15 , but recording SNR becomes to very low.
Read back MICFIL Control register 2:
root@imx8mmevk:/usr# /unit_tests/memtool -32 0x30080004 1
Reading 0x1 count starting at address 0x30080004
How to improve recording quality?