MCCIRM Freescale Semiconductor / Motorola, MCCIRM Datasheet - Page 40

• Manufacturer Part Number: MCCIRM
• Description: MCCIRM Multi-Channel Communications Interface Reference Manual
• Manufacturer: Freescale Semiconductor / Motorola

SPI Submodule
4.2 Introduction
Reference Manual
40
The SPI submodule communicates with external peripherals and other
MCUs via a synchronous serial bus. The SPI (serial peripheral interface)
is fully compatible with the SPI systems found on other Motorola
devices, such as the M68HC11 and M68HC05 Families. The SPI can
perform full duplex 3-wire or half duplex 2-wire transfers. Serial transfer
of eight or 16 bits can begin with the most significant bit (MSB) or least
significant bit (LSB). The system can be configured as a master or slave
device.
Clock control logic allows a selection of clock polarity and a choice of two
clocking protocols to accommodate most available synchronous serial
peripheral devices. When the SPI is configured as a master, software
selects one of 254 different bit rates for the serial clock.
During an SPI transfer, data is simultaneously transmitted (shifted out
serially) and received (shifted in serially). A serial clock line synchronizes
shifting and sampling of the information on the two serial data lines. A
slave-select line allows individual selection of a slave SPI device. Slave
devices which are not selected do not interfere with SPI bus activities.
On a master SPI device, the slave-select line optionally can be used to
indicate a multiple-master bus contention.
Error-detection logic is included to support interprocessor interfacing. A
write-collision detector indicates when an attempt is made to write data
to the serial shift register while a transfer is in progress. A
multiple-master mode-fault detector automatically disables SPI output
drivers if more than one MCU simultaneously attempts to become bus
master.
Table 4-1
operation. All registers, bits, and fields referred to are discussed fully
later in this section or in
Freescale Semiconductor, Inc.
For More Information On This Product,
is a quick reference guide to the bits and fields involved in SPI
Go to: www.freescale.com
SPI Submodule
Section 3. Configuration and
Multichannel Communication Interface — Rev. 1.0
Control.
MOTOROLA