HD404339 Datasheet, PDF (55/80 Pages) Hitachi Semiconductor – 4-bit HMCS400-Series microcomputer with large-capacity memory

State
MCU reset
PMRA write
SMR write
PMRC write
SRL, SRU
write
STS
instruction
SCK pin
(input)
SO pin
,
_IFS
State
_{MCU reset}
PMRA write
SMR write
PMRC write
SRL, SRU
write
STS
instruction
SCK pin
(output)
SO pin
^IFS
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
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
Internal clock mode
HD404339 Series
Transmit clock
wait state
STS wait state
Dummy write for
state transition
Output level control in
idle states
MSB
Flag reset at transfer completion
STS wait state
Output level control in
idle states
MSB
Flag reset at transfer completion
Figure 41 Example of Serial Interface Operation Sequence
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