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W541C250
- 4 -
Publication Release Date: Feb 2002
Revision A2
PAD DESCRIPTION
SYMBOL
XIN
I/O
I
FUNCTION
Input pin for oscillator.
Connected to crystal or resistor to generate system clock by code option.
External 15~20pF capacitor uses to get accurate freq in crystal mode.
XOUT
O
Output pin for oscillator.
Connected to crystal or resistor to generate system clock by code option.
20PF capacitor is built in internal for crystal mode.
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
4-bit port for input only.
RE0
RE3
O Output port only.
This port provides high sink current to drive LEDs.
MFP
O
Output pin only.
This pin can output modulating or nonmodulating frequency, or Timer 1
clock output specified by mode register 1 (MR1).
INT
I
External interrupt pin with pull-high resistor.
RES
I
System reset pin with pull-high resistor.
SEG0
SEG23
O
LCD segment output pins.
Can also be used as DC output ports specified by code option.
COM0
COM3
O
LCD common signal output pins.
Static
COM0
COM1
COM2
COM3
Used
Not Used
1/2 Duty
Not Used
Not Used
Not Used
Not Used
1/3 Duty
Not Used
1/4 Duty
Used
Used
Used
Used
Used
Used
Used
Used
Used
The LCD alternating frequency can be selected by code option.
DH1, DH2
I
Connection terminals for voltage doubler (halver) capacitor.
V
DD1
, V
DD2
V
DD3
I
Positive (+) supply voltage terminal.
Refer to Functional Description.
V
DD
I
Positive power supply (+).
V
SS
I
Negative power supply (-).