Pin Description

Pin Name

I/O

ROM Code

Option

Description

PB0/AN0

PB1/AN1

PB2/AN2

PB3/AN3

PB4/AN4

PB5/AN5

PB6/AN6

PB7/AN7

I/O

Pull-high

Bidirectional 8-bit input/output port. Software instructions determine the

CMOS output, Schmitt trigger input with or without pull-high resistor (deter-

mined by pull-high option: port option) or A/D input.

Once a PB line is selected as an A/D input (by using software control), the

I/O function and pull-high resistor are disabled automatically.

PA0~PA2

PA3/PFD

PA4/TMR

PA5/INT

PA6/SDA

PA7/SCL

I/O

Pull-high

Wake-up

PA3 or PFD

I/O or Serial Bus

Bidirectional 8-bit input/output port. Each bit can be configured as wake-up

input by ROM code option. Software instructions determine the CMOS out-

put or Schmitt trigger input with or without pull-high resistor (determined by

pull-high options: bit option). The PFD, TMR and INT are pin-shared with

ternal registers related to PA6 and PA7 can not be used.

VSS

¾¾

Negative power supply, ground.

PC0~PC4

I/O

Pull-high

Bidirectional 5-bit input/output port. Software instructions determine the

CMOS output, Schmitt trigger input with or without pull-high resistor (deter-

mine by pull-high option: port option).

PD0/PWM0

PD1/PWM1

I/O

Pull-high

I/O or PWM

Bidirectional 2-bit input/output port. Software instructions determine the

CMOS output, Schmitt trigger input with or without a pull-high resistor (de-

termined by pull-high option: port option). The PWM0/PWM1 output func-

tion are pin-shared with PD0/PD1 (dependent on PWM optios).

RES

I

¾

Schmitt trigger reset input. Active low.

VDD

¾¾

Positive power supply

OSC1

OSC2

I

O

Crystal

or RC

OSC1, OSC2 are connected to an RC network or a Crystal (determined by

ROM code option) for the internal system clock. In the case of RC opera-

tion, OSC2 is the output terminal for 1/4 system clock.

Absolute Maximum Ratings

Storage Temperature ............................-50°Cto125°C

Operating Temperature...........................-40°Cto85°C

Note: These are stress ratings only. Stresses exceeding the range specified under ²Absolute Maximum Ratings² may

cause substantial damage to the device. Functional operation of this device at other conditions beyond those

listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliabil-

ity.

HT46R23

Rev. 1.30

3

August 17, 2001