XC912BC32CFU8 Motorola Semiconductor Products, XC912BC32CFU8 Datasheet - Page 214

• Manufacturer Part Number: XC912BC32CFU8
• Description: M68HC12B Family Data Sheet
• Manufacturer: Motorola Semiconductor Products

Serial Interface
14.3 Serial Peripheral Interface (SPI)
Data Sheet
214
÷
SP0BR SPI BAUD RATE REGISTER
2
÷
4
INTERRUPT
REQUEST
÷
SPI
8
SAME AS E RATE
MCU P CLOCK
÷
16
DIVIDER
SELECT
÷
32
SP0SR SPI STATUS REGISTER
The serial peripheral interface (SPI) allows the MCU to communicate
synchronously with peripheral devices and other microprocessors. The SPI system
in the MCU can operate as a master or as a slave. The SPI is also capable of
interprocessor communications in a multiple master system.
When the SPI is enabled, all pins that are defined by the configuration as inputs will
be inputs regardless of the state of the DDRS bits for those pins. All pins that are
defined as SPI outputs will be outputs only if the DDRS bits for those pins are set.
Any SPI output whose corresponding DDRS bit is cleared can be used as a
general-purpose input.
A bidirectional serial pin is possible using the DDRS as the direction control.
SPI CONTROL
Figure 14-11. Serial Peripheral Interface Block Diagram
÷
64
÷
128
÷
256
SP0DR SPI DATA REGISTER
Serial Interface
SHIFT CONTROL LOGIC
8-BIT SHIFT REGISTER
INTERNAL BUS
MSTR
SPE
READ DATA BUFFER
SP0CR1 SPI CONTROL REGISTER 1
CLOCK
LOGIC
CLOCK
SWOM
LSBF
SP0CR2 SPI CONTROL REGISTER 2
S
M
M
S
S
M
CONTROL
LOGIC
M68HC12B Family — Rev. 8.0
PIN
MISO
MOSI
SCK
PS7
PS4
PS5
PS6
SS
MOTOROLA