HD404339 Datasheet, PDF (53/80 Pages) Hitachi Semiconductor – 4-bit HMCS400-Series microcomputer with large-capacity memory

Table 10
SMR
Bit 3
1
Serial Interface Operating Modes
PMRA
Bit 1
0
1
Bit 0
0
1
0
1
Operating Mode
Continuous clock output mode
Transmit mode
Receive mode
Transmit/receive mode
HD404339 Series
STS wait state
(Octal counter = 000,
transmit clock disabled)
MCU reset
SMR write
STS instruction
SMR write (IFS ← 1)
Transmit clock wait state
(Octal counter = 000)
Transmit clock
8 transmit clocks or STS instruction (IFS ← 1)
External clock mode
Transfer state
(Octal counter = 000)
SMR write
STS wait state
(Octal counter = 000,
transmit clock disabled)
MCU reset
Continuous clock output state
(PMRA 0, 1 = 00)
SMR write
STS instruction
Transmit clock
Transmit clock wait state
(Octal counter = 000)
Transmit clock
STS instruction (IFS ← 1)
8 transmit clocks or
SMR write (IFS← 1)
Transfer state
(Octal counter = 000)
Internal clock mode
Figure 39 Serial Interface State Transitions
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