Preliminary W541E20X

Publication Release Date: June 2003

- 5 -

Revision A2

PIN DESCRIPTION

SYMBOL

I/O

FUNCTION

XIN

I

Input pin for oscillator.

Connected to crystal or resistor to generate system clock by code option.

External 10~20pF 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

−RA2,

RA3 (DATA)

I/O

Input/Output port.

Input/output mode specified by port mode 1 register (PM1). When used as

output port, can provide high sink current for driving LED.

RB0

−RB3

I/O

Input/Output port.

Input/output mode specified by port mode 2 register (PM2). When used as

output port, can provide high sink current for driving LED.

RC0

−RC3

I/O

Input/Output port.

Input/output mode specified by port mode 4 register (PM4). Each pin has

an independent interrupt capability in input mode.

RD0

−RD3

I/O

Input/Output port.

Input/output mode specified by port mode 5 register (PM5).

RE0/DOUT,

RE1/CLKO,

RE2/DIN,

RE3/CLKI

I/O

Special input/output port.

This port can be configured by software to act as the output of internal

port RT or the serial I/O port. When used as output port, can provide high

sink current for driving LED.

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

(MODE)

1

I

External interrupt pin.

and floating input pin.

RES

1

I

System reset pin.

used to reset this chip. It is a low active and floating input pin.

I

Positive power supply (+).

I

Negative power supply (-).

Note: There are internal pull-high resistors in these pins of W741C20X.