NXP Semiconductors K22F series, Reference Manual, Page: 1141 / 1407

SPIx_CTARn_SLAVE field descriptions
Field Description
31
Reserved
Always write the reset value to this field.
This field is reserved.
30–27
FMSZ Frame Size
The number of bits transfered per frame is equal to the FMSZ field value plus 1. Note that the minimum
valid value of frame size is 4.
26
CPOL
Clock Polarity
Selects the inactive state of the Serial Communications Clock (SCK).
NOTE: In case of Continuous SCK mode, when the module goes in low power mode(disabled), inactive
state of SCK is not guaranted.
0 The inactive state value of SCK is low.
1 The inactive state value of SCK is high.
25
CPHA
Clock Phase
Selects which edge of SCK causes data to change and which edge causes data to be captured. This bit is
used in both master and slave mode. For successful communication between serial devices, the devices
must have identical clock phase settings. In Continuous SCK mode, the bit value is ignored and the
transfers are done as if the CPHA bit is set to 1.
0 Data is captured on the leading edge of SCK and changed on the following edge.
1 Data is changed on the leading edge of SCK and captured on the following edge.
24–23
Reserved
This field is reserved.
This read-only field is reserved and always has the value 0.
22
Reserved
This field is reserved.
Reserved This field is reserved.
Chapter 45 Serial Peripheral Interface (SPI)
K22F Sub-Family Reference Manual, Rev. 4, 08/2016
NXP Semiconductors 1141