Pin Description

Pin Name

I/O

Options

Description

PA0~PA2

PA3/PFD

PA4/TMR

PA5/INT

PA6~PA7

I/O

Pull-high

Wake-up

PA3 or PFD

Bidirectional 8-bit input/output port. Each individual bit on this port can be

configured as a wake-up input by configuration option. Software instruc-

tions determine if the pin is a CMOS output or Schmitt trigger input. Config-

uration options determine which pin on this port have pull-high resistors.

The PFD, TMR and external interrupt input are pin-shared with PA3, PA4,

and PA5 respectively.

PB0/AN0~

PB7/AN7

I/O

Pull-high

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

CMOS output or Schmitt trigger input with or without pull-high resistor.

Configuration options determine which pin on this port have pull-high resis-

tors. PB is pin-shared with the A/D input pins. The A/D inputs are selected

via software instructions Once selected as an A/D input, the I/O function

and pull-high resistor functions are disabled automatically.

PC0~PC4

I/O

Pull-high

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

CMOS output or Schmitt trigger input with or without pull-high resistor.

Configuration options determine which pin on this port have pull-high resis-

tors.

PD0/PWM

I/O

Pull-high

PD0 or PWM

Bidirectional 1-bit input/output port. Software instructions determine the

CMOS output or Schmitt trigger input with or without pull-high resistor. One

configuration option determines which pin on this port has pull-high resis-

tor. PD0 is pin-shared with the PWM output selected via configuration op-

tion.

OSC1

OSC2

I

O

Crystal or RC

OSC1, OSC2 are connected to an external RC network or external crystal

(determined by configuration option) for the internal system clock. For ex-

ternal RC system clock operation, OSC2 is an output pin for 1/4 system

clock.

RES

I

¾

Schmitt trigger reset input, active low.

VDD

¾¾

Positive power supply

VSS

¾¾

Negative power supply, ground

VREF

I

¾

A/D Converter Reference Input voltage pins. Connect this pin to the de-

sired A/D reference voltage.

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.

HT46R53/HT46R54

Rev. 1.40

3

July 12, 2005