4
MITSUBISHI MICROCOMPUTERS
4570 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
Clock input
Clock output
Output port D
I/O port P0
I/O port P1
Input port P2
I/O port P3
Input port P4
Carrier wave output
for remote control
Interrupt input
Timer output
Voltage drop
detection circuit
enable
Input/Output
—
—
Input
I/O
Input
Output
Output
I/O
I/O
I/O
I/O
Input
Output
Input
Output
Input
Function
Connected to a plus power supply.
Connected to a 0 V power supply.
Connect CNV
SS
to V
SS
and apply “L” (0V) to CNV
SS
certainly.
An N-channel open-drain I/O pin for a system reset. A pull-up transistor and a
capacitor are built-in this pin. When the watchdog timer causes the system to be
reset or the low-supply voltage is detected, the
RESET
pin outputs “L” level.
I/O pins of the clock generating circuit. Connect a ceramic resonator between X
IN
pin and X
OUT
pin. A feedback resistor is built-in between them.
Each pin of port D has an independent 1-bit wide output function. Port D
9
is also
used as T
OUT
output pin. The output structure is N-channel open-drain.
4-bit I/O port. It can be used as an input port when the output latch is set 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.
4-bit I/O port. It can be used as an input port when the output latch is set 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.
2-bit input port. Port P2
1
is also used as the INT input pin.
4-bit I/O port. It can be used as an input port when the output latch is set to “1.”
The output structure is N-channel open-drain.
4-bit input port. Every pin of the ports has a key-on wakeup function and a pull-up
function. Both functions can be switched by software.
Carrier wave output pin for remote control transmit. The output structure is the
CMOS circuit.
INT input pin accepts an external interrupt and has a key-on wakeup function. INT
input pin is also used as port P2
1
.
T
OUT
output pin has the function to output the timer 2 underflow signal divided by
2. T
OUT
output pin is also used as port D
9
.
VDCE pin is used to control the operation/stop of the voltage drop detection circuit.
The circuit is operating when “H” level is input to the VDCE pin. It is stopped when
“L” level is input to this pin.
X
IN
X
OUT
D
0
–D
9
P0
0
–P0
3
P1
0
–P1
3
P2
0
, P2
1
P3
0
–P3
3
P4
0
–P4
3
CARR
INT
T
OUT
VDCE