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Half-duplex communication of SPI
One clock line and one bidirectional data line
Enable this mode by setting BMEN of SPI_CTRL1 register
Control the data line to be input or output by setting BMOEN bit of
SPI_CTRL1 register
SCK pin is used as clock, MOSI pin is used in master device to
transmit data, and MISO pin is used in slave device to transmit data
Data transmitting and receiving process in different SPI modes
Table 101 Run Mode of SPI
Mode
Configure
Data pin
Full duplex mode of master device
BMEN=0
,
RXOMEN=0
MOSI transmits; MISO receives
Unidirectional receiving mode of
master device
BMEN=0
,
RXOMEN=1
MOSI is not used; MISO
receives
Bidirectional transmitting mode of
master device
BMEN=1
,
BMOEN=1
MOSI transmits; MISO is not
used
Bidirectional receiving mode of
master device
BMEN=1
,
BMOEN=0
MOSI is not used; MISO
receives
Full duplex mode of slave device
BMEN=0
,
RXOMEN=0
MOSI receives, and MISO
transmits
Unidirectional receiving mode of
slave device
BMEN=0
,
RXOMEN=1
MOSI receives, while MISO is
not used
Bidirectional transmitting mode of
slave device
BMEN=1
,
BMOEN=1
MOSI is not used, and MISO
transmits
Bidirectional receiving mode of
slave device
BMEN=1
,
BMOEN=0
MOSI receives, while MISO is
not used
Figure 90 Connection in Full Duplex Mode
Master device
SCK
MOSI
NSS
MISO
Slave device
SCK
MOSI
NSS
MISO