Figure 440. Slot Size Configuration With Fboff = 0 In Sai_Xslotr; Figure 441. First Bit Offset - ST STM32L4x6 Reference Manual

RM0351
It is possible to choose the position of the first data bit to transfer within the slots. This offset
is configured by FBOFF[4:0] bits in the SAI_xSLOTR register. 0 values will be injected in
transmitter mode from the beginning of the slot until this offset position is reached. In
reception, the bit in the offset phase is ignored. This feature targets the LSB justified
protocol (if the offset is equal to the slot size minus the data size).
It is mandatory to respect the following conditions to avoid bad SAI behavior:
FBOFF ≤ (SLOTSZ - DS),
DS ≤ SLOTSZ,
NBSLOT x SLOTSZ ≤ FRL (frame length),
The number of slots must be even when bit FSDEF in the SAI_xFRCR register is set.
In AC'97 and SPDIF protocol (bit PRTCFG[1:0] = 10 or PRTCFG[1:0] = 01), the slot size is
automatically set as defined in

Figure 440. Slot size configuration with FBOFF = 0 in SAI_xSLOTR

Section 39.3.9: AC'97 link
DocID024597 Rev 3

Figure 441. First bit offset

Serial audio interface (SAI)
controller.
1327/1693
1362