Serial peripheral interface (SPI)
RM0090
910/1731
DocID018909 Rev 11
Bit
10
RXONLY:
Receive only
This bit combined with the BIDImode bit selects the direction of transfer in 2-line
unidirectional mode. 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: This bit is not used in I
2
S mode.
When disabling the SPI, follow the procedure described in
.
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.