4
MITSUBISHI MICROCOMPUTERS
4570 Group
SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER
PIN DESCRIPTION
Name
Power supply
Ground
CNVSS
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
I/O
Input
Output
Input
Output
Input
Function
Connected to a plus power supply.
Connected to a 0 V power supply.
Connect CNVSS to VSS and apply “L” (0V) to CNVSS 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 XIN
pin and XOUT pin. A feedback resistor is built-in between them.
Each pin of port D has an independent 1-bit wide output function. Port D9 is also
used as TOUT 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 P21 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 P21.
TOUT output pin has the function to output the timer 2 underflow signal divided by
2. TOUT output pin is also used as port D9.
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.
Pin
VDD
VSS
CNVSS
RESET
XIN
XOUT
D0–D9
P00–P03
P10–P13
P20, P21
P30–P33
P40–P43
CARR
INT
TOUT
VDCE