HD404356 Datasheet, PDF (65/100 Pages) Hitachi Semiconductor – 4-bit HMCS400-Series microcomputer

State
MCU reset
PMRA write
SMR write
PMRC write
SRL, SRU write
STS instruction
SCK pin (input)
SO pin
STS wait state
Transmit clock
wait state
Transfer state
Port selection
External clock selection
Output level control in
idle states
Data write for transmission
Undefined
LSB
HD404358 Series
Transmit clock
wait state
STS wait state
Dummy write for
state transition
Output level control in
idle states
MSB
,
_IFS
State
_{MCU reset}
PMRA write
SMR write
PMRC write
SRL, SRU write
STS instruction
SCK pin (output)
SO pin
STS wait state
External clock mode
Transmit clock
wait state
Transfer state
Port selection
Internal clock selection
Output level control in
idle states
Data write for transmission
Undefined
LSB
Flag reset at transfer completion
STS wait state
Output level control in
idle states
MSB
IFS
^{Internal clock mode}
Flag reset at transfer completion
Figure 53 Example of Serial Interface Operation Sequence
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