
26
MITSUBISHI MICROCOMPUTERS
7477/7478 GROUP
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
Fig. 19 Block diagram of ports P0, P1
0
–P1
3
Direction register
Port latch
Interrupt control circuit
Tr1
Port P0
Data bus
Port P0
Tr2
Port P1
3
Data bus
T34M
7
T
1
Data bus
Tr3
Port P1
2
Data bus
T12M
3
T
0
Port P1
1
Tr4
Data bus
Tr5
Data bus
Port P1
0
Ports P1
0
– P1
3
Tr1 to Tr5 are pull-up transistors.
Pull-up control
register
Port latch
Pull-up control
register
Port latch
Port latch
Port latch
Direction register
Direction register
Direction register
Direction register