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The mode fault flag is cleared automatically by a read of the SPI Status Register (with
MODF set) followed by a write to SPI Control Register 1. If the mode fault flag is
cleared, the SPI becomes a normal master or slave again.
35.5.11 Low-power mode options
This section describes the low-power mode options.
35.5.11.1 SPI in Run mode
In Run mode, with the SPI system enable (SPE) bit in the SPI Control Register 1 clear,
the SPI system is in a low-power, disabled state. SPI registers can still be accessed, but
clocks to the core of this module are disabled.
35.5.11.2 SPI in Wait mode
SPI operation in Wait mode depends upon the state of the SPISWAI bit in SPI Control
Register 2.
• If C2[SPISWAI] is clear, the SPI operates normally when the CPU is in Wait mode.
• If C2[SPISWAI] is set, SPI clock generation ceases and the SPI module enters a
power conservation state when the CPU is in wait mode.
• If C2[SPISWAI] is set and the SPI is configured for master, any transmission
and reception in progress stops at Wait mode entry. The transmission and
reception resumes when the SPI exits Wait mode.
• If C2[SPISWAI] is set and the SPI is configured as a slave, any transmission and
reception in progress continues if the SPSCK continues to be driven from the
master. This keeps the slave synchronized to the master and the SPSCK.
If the master transmits data while the slave is in wait mode, the slave continues
to send data consistent with the operation mode at the start of wait mode (that is,
if the slave is currently sending its SPIx_DH:SPIx_DL to the master, it continues
to send the same byte. Otherwise, if the slave is currently sending the last data
received byte from the master, it continues to send each previously received data
from the master byte).
Freescale Semiconductor, Inc.
KL27 Sub-Family Reference Manual , Rev. 5, 01/2016
Chapter 35 Serial Peripheral Interface (SPI)
601
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