MITSUBISHI MICROCOMPUTERS
4250 Group
SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER
MULTIFUNCTION
Pin
G
0
G
1
D
2
INT
T
OUT
C
Multifunction
Pin
INT (Note 2)
T
OUT
(Note 2)
C (Note 2)
G
0
G
1
D
2
D
3
Multifunction
D
3
K
K (Note 2)
Notes 1: Pins except above have just single function.
2: The I/O of ports D
2
, D
3
and G
0
, and the input of port G
1
can be used even when ports C and K and pins INT and T
OUT
are
selected.
CONNECTIONS OF UNUSED PINS
Pin
F
0
, F
1
G
0
/INT, G
1
/T
OUT
G
2
, G
3
S
0
–S
3
Connection
Connect to V
SS
pin.
Open or connect to V
SS
pin. (Note 1)
Connect to V
SS
pin. (Note 2)
D
0
, D
1
D
2
/C, D
3
/K
Pin
Connection
Connect to V
SS
pin.
Open or connect to V
SS
pin. (Note 3)
Notes 1: When pins G
0
/INT, G
1
/T
OUT
, G
2
and G
3
are connected to V
SS
pin, turn off their pull-up transistors (Pull-up control register
PU0=“!0
2
”) and also invalidate the key-on wakeup functions of pins G
1
/T
OUT
, G
2
and G
3
(Key-on wakeup contorl register
K0=“!!0!
2
”) by software. When the POF instruction is executed while these pins are connected to V
SS
and the key-on
wakeup functions are left valid, the system returns from RAM back-up state by recognizing the return condition immediately
after going into the RAM back-up state. When these pins are open, turn on their pull-up transistors (Pull-up control register
PU0=“!1
2
”) by software.
2: When ports S
0
–S
3
are connected to V
SS
pin, invalidate the key-on wakeup functions (Key-on wakeup contorl register
K0=“!!!0
2
”) by software. When the POF instruction is executed while these pins are connected to V
SS
and the key-on
wakeup functions are left valid, the system returns from RAM back-up state by recognizing the return condition immediately
after going into the RAM back-up state.
3: When ports D
2
/C and D
3
/K are connected to V
SS
pin, turn off their pull-up transistors (register PU0=“0!
2
”) by software.
When these pins are open, turn on their pull-up transistors (register PU0=“1!
2
”) by software.
(Note when connecting to V
SS
and V
DD
)
• Connect the unused pins to V
SS
or V
DD
at the shortest distance and use the thick wire against noise.
5
RENESAS [ RENESAS TECHNOLOGY CORP ]
