MC68HC705P9 Datasheet, PDF (123/160 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Freescale Semiconductor, Inc.
Serial Input/Output Port (SIOP)
Timing
10.4.2 Data Movement
Connecting the SIOP data register of a master MCU with the SIOP of a
slave MCU forms a 16-bit circular shift register. During an SIOP transfer,
the master shifts out the contents of its SIOP data register on its
PB5/SDO pin. At the same time, the slave MCU shifts out the contents
of its SIOP data register on its PB5/SDO pin. Figure 10-4 shows how the
master and slave exchange the contents of their data registers.
SDO
SDO
SIOP SHIFT REGISTER
SDI
SIOP SHIFT REGISTER
SIOP IN
MASTER MODE
SCK
SDI
SIOP IN
SLAVE MODE
SCK
Figure 10-4. Master/Slave SIOP Shift Register Operation
10.5 Timing
t_SCK
t_SCKL
SCK
t_V
SDO
SDI
t_HO
MSB
BIT 1
t_H
t_S
MSB
VALID
DATA
Figure 10-5. SIOP Timing
LSB
LSB
MC68HC705P9 — Rev. 4.0
MOTOROLA
Serial Input/Output Port (SIOP)
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Technical Data
123