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MITSUBISHI MICROCOMPUTERS
7641 Group
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
SCSGCLK
φ
P80/UTXD2/SRDY
P81/URXD2/SCLK
P83/RTS2/STXD
P82/CTS2/SRXD
Serial I/O internal
“1” clock select bit
“0”
Synchronous
clock select bit
“0”
P80 latch
“1”
SRDY output select bit
Synchronization
circuit
1/2
1/4
1/8
1/16
1/32
1/64
1/128
“1”
1/256
Data bus
Internal synchronous
“0”
clock selection bits
External clock
“0”
P81 latch
“1”
Serial I/O port select bit
Serial I/O counter (3)
SPI mode select bit
“0”
P83 latch
“1” Serial I/O port select bit
“1”
“0” SRXD input enable bit
Serial I/O shift register (8)
Serial I/O
interrupt request
Fig. 24 Block diagram of serial I/O
29