ST STM32G4 Series Reference Manual page 1772

Serial audio interface (SAI)
Bit Fields
FSPOL
FSOFF
FBOFF
SLOTSZ
NBSLOT
SLOTEN
NODIV
MCKDIV
Adjusting the bitstream clock rate
To properly program the SAI TDM interface, the user application must take into account the
settings given in
1. Adjust the bit clock frequency (F
PDM bitstream clock, using the following formula:
F
SCK_A
MICNBR can be 0,1,2 or 3 (0 = 2 microphones., see
2. Set the frame length (FRL) using the following formula
FRL
3. Configure the slot size (DS) to a multiple of (FRL+1).
1772/2083
Table 360. TDM settings (continued)
Values
1 FS is active High
0 FS is asserted on the first bit of slot 0
0 No offset on slot
0 Slot size = data size
To be adjusted according to the required data format, in accordance to the
X
slot size, and the frame length (FRL and DS). See
X To be adjusted according to NBSLOT
1 No need to generate a master clock MCLK
Depends on the frequency provided to sai_a_ker_ck input.
X
This parameter shall be adjusted to generate the proper bitstream clock
frequency. See
Table 360, and follow the below rules:
× (
= F MICNBR
PDM_CK
( × (
16 MICNBR
=
RM0440 Rev 1
Comments
Table 361.
) according to the required frequency for the
SCK_A
) ×
+ 1 2
Section
) ) 1
1
+ –
RM0440
Table 361.
39.5.17)