17.4 SPI0 Control Registers
17.4.1 SPI0CFG: SPI0 Configuration
Bit
7
6
5
4
3
2
1
0
Name
SPIBSY
MSTEN
CKPHA
CKPOL
SLVSEL
NSSIN
SRMT
RXE
Access
R
RW
RW
RW
R
R
R
R
Reset
0
0
0
0
0
1
1
1
SFR Page = 0x0, 0x20; SFR Address: 0xA1
Bit
Name
Reset
Access Description
7
SPIBSY
0
R
SPI Busy.
This bit is set to logic 1 when a SPI transfer is in progress (master or slave mode).
6
MSTEN
0
RW
Master Mode Enable.
Value
Name
Description
0
MASTER_DISABLED
Disable master mode. Operate in slave mode.
1
MASTER_ENABLED
Enable master mode. Operate as a master.
5
CKPHA
0
RW
SPI0 Clock Phase.
Value
Name
Description
0
DATA_CEN-
TERED_FIRST
Data centered on first edge of SCK period.
1
DATA_CEN-
TERED_SECOND
Data centered on second edge of SCK period.
4
CKPOL
0
RW
SPI0 Clock Polarity.
Value
Name
Description
0
IDLE_LOW
SCK line low in idle state.
1
IDLE_HIGH
SCK line high in idle state.
3
SLVSEL
0
R
Slave Selected Flag.
This bit is set to logic 1 whenever the NSS pin is low indicating SPI0 is the selected slave. It is cleared to logic 0 when NSS
is high (slave not selected). This bit does not indicate the instantaneous value at the NSS pin, but rather a de-glitched ver-
sion of the pin input.
2
NSSIN
1
R
NSS Instantaneous Pin Input.
This bit mimics the instantaneous value that is present on the NSS port pin at the time that the register is read. This input is
not de-glitched.
1
SRMT
1
R
Shift Register Empty.
This bit will be set to logic 1 when all data has been transferred in/out of the shift register, and there is no new information
available to read from the transmit buffer or write to the receive buffer. It returns to logic 0 when a data byte is transferred to
the shift register from the transmit buffer or by a transition on SCK.
0
RXE
1
R
RX FIFO Empty.
This bit indicates when the RX FIFO is empty. If a read is performed when RXE is set, the last byte will be returned.
EFM8UB3 Reference Manual
Serial Peripheral Interface (SPI0)
silabs.com
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