MITSUBISHI MICROCOMPUTERS
4250 Group
SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER
PIN DESCRIPTION
Pin
V
DD
V
SS
CNV
SS
RESET
Name
Power supply
Ground
CNV
SS
Reset input
System clock input
System clock output
I/O port F
I/O port G
Input/Output
—
—
—
Input
Input
Output
I/O
I/O
Connected to a plus power supply.
Connected to a 0 V power supply.
Function
Connect CNV
SS
to V
SS
and apply “L” (0V) to CNV
SS
certainly.
Reset pulse input pin
I/O pins of the system clock generating circuit. Connect pins X
IN
and X
OUT
directly.
Then, pull up X
IN
pin through a resistor and pull down X
OUT
pin through a capacitor.
2-bit I/O port; for input use, set the latch of the specified bit to “1.” The output
structure is N-channel open-drain.
4-bit I/O port. For input use, set the latch of the specified bit to “1.” The output
structure is N-channel open-drain. Every pin of the ports has a key-on wakeup
function and a pull-up function. Both functions can be switched by software.
Ports G
0
and G
1
are also used as pins INT and T
OUT
, respectively.
X
IN
X
OUT
F
0
, F
1
G
0
–G
3
S
0
–S
3
I/O port S
I/O
4-bit I/O port. For input use, set the latch of the specified bit to “1.” The output
structure is N-channel open-drain. Every pin of the ports has a key-on wakeup
function which can be switched by software. Also, it is used to perform the logic
operation using register A.
Each pin of port D has an independent 1-bit wide I/O function. For input use, set
the latch of the specified bit to “1.” The output structure is N-channel open-drain.
Ports D
2
and D
3
are also used as ports C and K, respectively.
1-bit I/O port. For input use, set the latch of the specified bit to “1.” The output
structure is N-channel open-drain. Port C has a pull-up function which can be
switched by software. It is also used as port D
2
.
1-bit I/O port. For input use, set the latch of the specified bit to “1.” The output
structure is N-channel open-drain. Port K has a pull-up function which can be
switched by software. It is also used as port D
3
.
T
OUT
pin has the function to output the timer 1 underflow signal divided by 2. It is
also used as port G
1
.
INT pin accepts an external interrupt. It also accepts the input signal to return the
system from the RAM back-up state. It is also used as port G
0
.
D
0
–D
3
I/O port D
I/O
C
I/O port C
I/O
K
I/O port K
I/O
T
OUT
INT
Timer output
Interrupt input
Output
Input
4
ETC [ ETC ]
