Serial peripheral interface/ inter-IC sound (SPI/I2S) RM0401
722/771 RM0401 Rev 3
Bit 11 DFF: Data frame format
0: 8-bit data frame format is selected for transmission/reception
1: 16-bit data frame format is selected for transmission/reception
Note: This bit should be written only when SPI is disabled (SPE = ‘0’) for correct operation.
It is not used in I
2
S mode.
Bit 10 RXONLY: Receive only mode enable
This bit enables simplex communication using a single unidirectional line to receive data
exclusively. Keep BIDIMODE bit clear when receive only mode is active.
This bit is also useful in a multislave system in which this particular slave is not accessed, the
output from the accessed slave is not corrupted.
0: full-duplex (Transmit and receive)
1: Output disabled (Receive-only mode)
Note: This bit is not used in I
2
S mode
Bit 9 SSM: Software slave management
When the SSM bit is set, the NSS pin input is replaced with the value from the SSI bit.
0: Software slave management disabled
1: Software slave management enabled
Note: This bit is not used in I
2
S mode and SPI TI mode
Bit 8 SSI: Internal slave select
This bit has an effect only when the SSM bit is set. The value of this bit is forced onto the
NSS pin and the IO value of the NSS pin is ignored.
Note: This bit is not used in I
2
S mode and SPI TI mode
Bit 7 LSBFIRST: Frame format
0: MSB transmitted first
1: LSB transmitted first
Note: This bit should not be changed when communication is ongoing.
It is not used in I
2
S mode and SPI TI mode
Bit 6 SPE: SPI enable
0: Peripheral disabled
1: Peripheral enabled
Note: When disabling the SPI, follow the procedure described in Section 25.3.10: Procedure
for disabling the SPI
.
This bit is not used in I
2
S mode.
Bits 5:3 BR[2:0]: Baud rate control
000: f
PCLK
/2
001: f
PCLK
/4
010: f
PCLK
/8
011: f
PCLK
/16
100: f
PCLK
/32
101: f
PCLK
/64
110: f
PCLK
/128
111: f
PCLK
/256
Note: These bits should not be changed when communication is ongoing.
They are not used in I
2
S mode.
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