mc9s12xs128 Freescale Semiconductor, Inc, mc9s12xs128 Datasheet - Page 436

• Manufacturer Part Number: mc9s12xs128
• Description: Hcs12 Microcontrollers 16-bit Automotive Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Serial Peripheral Interface (S12SPIV5)
For a detailed description of operating modes, please refer to
15.1.4
Figure 15-1
data registers, shifter logic, baud rate generator, master/slave control logic, and port control logic.
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Run mode
This is the basic mode of operation.
Wait mode
SPI operation in wait mode is a configurable low power mode, controlled by the SPISWAI bit
located in the SPICR2 register. In wait mode, if the SPISWAI bit is clear, the SPI operates like in
run mode. If the SPISWAI bit is set, the SPI goes into a power conservative state, with the SPI clock
generation turned off. If the SPI is configured as a master, any transmission in progress stops, but
is resumed after CPU goes into run mode. If the SPI is configured as a slave, reception and
transmission of data continues, so that the slave stays synchronized to the master.
Stop mode
The SPI is inactive in stop mode for reduced power consumption. If the SPI is configured as a
master, any transmission in progress stops, but is resumed after CPU goes into run mode. If the SPI
is configured as a slave, reception and transmission of data continues, so that the slave stays
synchronized to the master.
Block Diagram
gives an overview on the SPI architecture. The main parts of the SPI are status, control and
S12XS Family Reference Manual, Rev. 1.10
Section 15.4.7, “Low Power Mode
Freescale Semiconductor
Options”.