MC68HC705P9 Datasheet, PDF (113/156 Pages) Motorola, Inc – HCMOS Microcontroller Unit

SIOP
Operation
PB6/SDI
The PB6/SDI pin is the SIOP data input. Valid SDI data must be present
for an SDI setup time, t_S, before the rising edge of the serial clock and
must remain valid for an SDI hold time, t_H, after the rising edge of the
serial clock. (See Table 1 and Table 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 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 4. Master/Slave SIOP Shift Register Operation
7-siop_a
MOTOROLA
SIOP
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