ST STM32F405 Reference Manual page 954

Serial audio interface (SAI)
Bit 6 MUTEVAL: Mute value. This bit is set and cleared by software.This bit has to be written before
enabling the audio block: SAIxEN.
0: Bit value 0 is sent during the MUTE mode.
1: Last values are sent during the MUTE mode.
This bit has a meaning only when the audio block is a transmitter and when the number of slots is
lower or equal to 2 and if the MUTE bit is set.
If more slots are declared, the bit value sent during the transmission in mute mode will be equal to 0,
whatever the value of this MUTEVAL bit.
if the number of slot is lower or equal to 2 and MUTEVAL = 1, the mute value transmitted for each
slot will be the ones sent during the previous frame.
Refer to
Bit 5 MUTE: Mute. This bit is set and cleared by software.
0: No Mute mode.
1: Mute mode enabled.
This bit has a meaning only when the audio block is a transmitter. The MUTE value is linked to the
MUTEVAL value if the number of slots is lower or equal to 2, or equal to 0 if it is greater than 2.
Refer to
Bit 4 TRIS: Tristate management on data line. This bit is set and cleared by software.
0: SD output line is still driven by the SAI when a slot is inactive.
1: SD output line is released (HI-Z) at the end of the last data bit of the last active slot if the next one
is inactive.
This bit has a meaning only if the audio block is configured to be a transmitter.
This bit should be configured when SAI is disabled.
Refer to
Bit 3 FFLUSH: FIFO flush. This bit is set by software. It is always read low.
0: No FIFO flush.
1: FIFO flush.
Writing 1 to the bit triggers the FIFO Flush. All the internal FIFO pointers (read and write) are
cleared.
Data still present in the FIFO will be lost in such case (no more transmission or received data lost).
This bit should be configured when SAI is disabled.
Before flushing SAI, DMA stream/interruption must be disabled
Bits 2:0 FTH: FIFO threshold. This bit is set and cleared by software.
000: FIFO empty
001: ¼ FIFO
010: ½ FIFO
011: ¾ FIFO
100: FIFO full
101: Reserved
110: Reserved
111: Reserved
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Section 29.12.1 for more details.
Section 29.12.1 for more details.
Section 29.12.4 for more details.
RM0090 Rev 18
RM0090