Chapter 37
Serial Peripheral Interface (SPI)
37.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances see the chip configuration information.
The serial peripheral interface (SPI) module provides for full-duplex, synchronous, serial
communication between the MCU and peripheral devices. These peripheral devices can
include other microcontrollers, analog-to-digital converters, shift registers, sensors, and
memories, among others.
The SPI runs at a baud rate up to the bus clock divided by two in master mode and up to
the bus clock divided by four in slave mode. Software can poll the status flags, or SPI
operation can be interrupt driven.
NOTE
For the actual maximum SPI baud rate, refer to the Chip
Configuration details and to the device’s Data Sheet.
The SPI also includes a hardware match feature for the receive data buffer.
The SPI includes an internal DMA interface to support continuous SPI transmission
through an on-chip DMA controller instead of through the CPU. This feature decreases
CPU loading, allowing CPU time to be used for other work.
37.1.1 Features
The SPI includes these distinctive features:
• Master mode or slave mode operation
• Full-duplex or single-wire bidirectional mode
KL25 Sub-Family Reference Manual, Rev. 3, September 2012
Freescale Semiconductor, Inc. 655
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