ST STM32L4+ Series Reference Manual page 1938

Serial audio interface (SAI)
53.6.4 SAI configuration register 2 (SAI_ACR2)
Address offset: 0x008
Reset value: 0x0000 0000
31 30 29
Res. Res. Res. Res.
15 14 13
COMP[1:0] CPL
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Bits 31:16 Reserved, must be kept at reset value.
Bits 15:14 COMP[1:0]: Companding mode.
These bits are set and cleared by software. The µ-Law and the A-Law log are a part of the CCITT
G.711 recommendation, the type of complement that will be used depends on CPL bit.
The data expansion or data compression are determined by the state of bit MODE[0].
The data compression is applied if the audio block is configured as a transmitter.
The data expansion is automatically applied when the audio block is configured as a receiver.
Refer to
00: No companding algorithm
01: Reserved.
10: µ-Law algorithm
11: A-Law algorithm
Note: Companding mode is applicable only when Free protocol mode is selected.
Bit 13 CPL: Complement bit.
This bit is set and cleared by software.
It defines the type of complement to be used for companding mode
0: 1's complement representation.
1: 2's complement representation.
Note: This bit has effect only when the companding mode is µ-Law algorithm or A-Law algorithm.
Bits 12:7 MUTECNT[5:0]: Mute counter.
These bits are set and cleared by software. They are used only in reception mode.
The value set in these bits is compared to the number of consecutive mute frames detected in
reception. When the number of mute frames is equal to this value, the flag MUTEDET will be set and
an interrupt will be generated if bit MUTEDETIE is set.
Refer to
1938/2301
28 27 26 25
Res. Res. Res.
12 11 10 9
MUTECNT[5:0]
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Section : Companding mode
Section : Mute mode for more details.
24 23 22 21
Res. Res. Res. Res.
8 7 6 5
MUTE
MUTE
VAL
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for more details.
RM0432 Rev 6
20 19 18 17
Res. Res. Res. Res.
4 3 2
F
TRIS FTH[2:0]
FLUSH
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RM0432
16
Res.
1 0
rw