
Preliminary W742E81A/W742C81A
Publication Release Date: April 2000
Revision A1
- 5 -
4. PIN DESCRIPTION
SYMBOL
I/O
FUNCTION
XIN2
I
Input pin for sub-oscillator.
Connected to 32.768 KHz crystal only.
XOUT2
O
Output pin for sub-oscillator with internal oscillation capacitor. Connected
to 32.768 KHz crystal only.
XIN1
I
Input pin for main-oscillator.
Connected to 3.58 MHz or 400 KHz crystal or RC to generate system
clock.
XOUT1
O
Output pin for main-oscillator.
Connected to 3.58 MHz or 400 KHz crystal or RC to generate system
clock.
RA0
RA3
I/O
Input/Output port.
Input/output mode specified by port mode 1 register (PM1).
RB0
RB3
I/O
Input/Output port.
Input/output mode specified by port mode 2 register (PM2).
RC0
RC3
I
4-bit port for input only.
Each pin has an independent interrupt capability.
RD0
RD3
I/O
Input/Output port.
Input/output mode specified by port mode 5 register (PM5).
RE0
RE3
RF0
RF3
MFP
O Output port only. With high sink current capacity for the LED application.
O Output port only.
O
Output pin only.
This pin can output modulating or nonmodulating frequency, or Timer 1
specified frequency. It can be selected by bit 0 of BUZCR (BUZCR.0).
DTMF
O
This pin can output dual-tone multifrequency signal for dialling.
RES
I
System reset pin with pull-high resistor.
SEG0
SEG39
COM0
COM3
O
LCD segment output pins.
O
LCD common signal output pins.
The LCD alternating frequency can be selected by code option.
DH1, DH2
I
Connection terminals for voltage doubler (halver) capacitor.
V
DD1
V
DD2
I
Positive (+) supply voltage terminal.
Refer to Functional Description.
V
DD
I
Positive power supply (+).
V
SS
I
Negative power supply (-).