38B5 Group User’s Manual
1-4
HARDWARE
PIN DESCRIPTION
Table 1 Pin description (1)
Pin
Name
Function
VCC, VSS
Power source
Apply voltage of 4.0–5.5 V to VCC
, and 0 V to VSS.
VEE
Pull-down
Apply voltage supplied to pull-down resistors of ports P0, P1, and P3.
power source
VREF
Reference
Reference voltage input pin for A-D converter.
voltage
AVSS
Analog power
Analog power source input pin for A-D converter.
source
Connect to VSS.
______
RESET
Reset input
Reset input pin for active “L.”
XIN
Clock input
Input and output pins for the main clock generating circuit.
Feedback resistor is built in between XIN pin and XOUT pin.
Connect a ceramic resonator or quartz-crystal oscillator between the XIN and XOUT pins to set the
oscillation frequency.
When an external clock is used, connect the clock source to the XIN pin and leave the XOUT pin open.
The clock is used as the oscillating source of system clock.
P00/FLD8–
I/O port P0
8-bit I/O port.
FLD automatic display
P07/FLD15
I/O direction register allows each pin to be individually programmed as either
pins
input or output.
At reset, this port is set to input mode.
A pull-down resistor is built in between port P0 and the VEE pin.
CMOS compatible input level.
High-breakdown-voltage P-channel open-drain output structure.
At reset, this port is set to VEE level.
P10/FLD16– Output port P1
8-bit output port.
FLD automatic display
P17/FLD23
A pull-down resistor is built in between port P1 and the VEE pin.
pins
High-breakdown-voltage P-channel open-drain output structure.
At reset, this port is set to VEE level.
P20/BUZ02/
I/O port P2
8-bit I/O port with the same function as port P0.
FLD automatic display
FLD0–
Low-voltage input level.
pins
P27/FLD7
High-breakdown-voltage P-channel open-drain output structure.
Buzzer output pin (P20)
P30/FLD24– Output port P3
8-bit output port.
FLD automatic display
P37/FLD31
A pull-down resistor is built in between port P3 and the VEE pin.
pins
High-breakdown-voltage P-channel open-drain output structure.
At reset, this port is set to VEE level.
P40/INT0,
I/O port P4
7-bit I/O port with the same function as port P0.
Interrupt input pins
P41/INT1,
CMOS compatible input level
In the mask option type P,
P42/INT3
N-channel open-drain output structure.
INT3 cannot be used.
P43/BUZ01
Buzzer output pin
P44/PWM1
PWM output pin
(Timer output pin)
P45/T1OUT,
Timer output pin
P46/T3OUT
P47/INT2
Input port P4
1-bit input port.
Interrupt input pin
CMOS compatible input level.
Function except a port function
XOUT
Clock output