mc68hc912dg128 Freescale Semiconductor, Inc, mc68hc912dg128 Datasheet - Page 266

• Manufacturer Part Number: mc68hc912dg128
• Description: M68hc12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Multiple Serial Interface
14.5.4 Bidirectional Mode (MOMI or SISO)
Technical Data
266
When SPE=1
Bidirectional
SPC0=0
SPC0=1
Normal
Mode
Mode
SWOM enables open drain output. PS4 becomes GPIO.
Figure 14-6. Normal Mode and Bidirectional Mode
Serial Out
Serial Out
Serial Out
Serial Out
Serial In
Serial In
Serial In
Serial In
SPI
SPI
SPI
SPI
SWOM enables open drain output.
In bidirectional mode, the SPI uses only one serial data pin for external
device interface. The MSTR bit decides which pin to be used. The MOSI
pin becomes serial data I/O (MOMI) pin for the master mode, and the
MISO pin becomes serial data I/O (SISO) pin for the slave mode. The
direction of each serial I/O pin depends on the corresponding DDRS bit.
Freescale Semiconductor, Inc.
Master Mode
DDRS5
DDRS5
For More Information On This Product,
DDS5
DDS5
MSTR=1
Go to: www.freescale.com
Multiple Serial Interface
MOMI
MOMI
PS4
PS4
MO
MO
MI
MI
SWOM enables open drain output. PS5 becomes GPIO.
Serial Out
Serial Out
Serial Out
Serial Out
Serial In
Serial In
Serial In
Serial In
SPI
SPI
SPI
SPI
SWOM enables open drain output.
Slave Mode
DDRS4
DDRS4
MSTR=0
DDS4
DDS4
MC68HC912DG128 — Rev 3.0
SISO
SISO
PS5
PS5
SO
SO
SI
SI
MOTOROLA