HT49C50 datasheet(6/52 Pages) HOLTEK

6 / 52 page

Pin Description

Pin Name

I/O

Mask

Option

Description

PA0/BZ

PA1/BZ

PA2

PA3/PFD

PA4~PA7

I/O

Wake-up

Pull-high

or None

CMOS or

NMOS

PA0~PA7 constitute an 8-bit bidirectional input/output port

with Schmitt trigger input capability. Each bit on port can be

configured as a wake-up input by mask option. PA0~PA3 can be

configured as a CMOS output or NMOS input/output with or

without pull-high resistor by mask option. PA4~PA7 are al-

ways pull-high NMOS input/output. Of the eight bits,

PA0~PA1 can be set as I/O pins or buzzer outputs by mask op-

tion. PA3 can be set as an I/O pin or as a PFD output also by

mask option.

PB0/INT0

PB1/INT1

PB2/TMR0

PB3/TMR1

PB4~PB7

PB0~PB7 constitute an 8-bit Schmitt trigger input port. Each

bit on port are pull-high resistor. Of the eight bits, PB0 and PB1

can be set as input pins or as external interrupt control pins

(INT0) and (INT1) respectively, by software application. PB2

and PB3 can be set as an input pin or as a timer/event counter

input pin TMR0 and TMR1 also by software application.

PC0~PC3

I/O

Pull-high

or None

CMOS or

NMOS

PC0~PC3 constitute a 4-bit bidirectional input/output port

with a schmitt trigger input capability. On the port, such can be

configured as CMOS output or NMOS input/output with or

without pull-high resistor by mask option.

VSS

Negative power supply, GND

VLCD

LCD power supply

V1,V2,C1,C2

Voltage pump

SEG32/COM3

COM2~COM0

1/3 or 1/4

Duty

SEG32 can be set as a segment or as a common output driver for

LCD panel by mask option. COM2~COM0 are outputs for LCD

panel plate.

SEG31~SEG0

LCD driver outputs for LCD panel segments

OSC4

OSC3

Real time clock oscillators

VDD

¾¾

Positive power supply

OSC2

OSC1

Crystal or

OSC1 and OSC2 are connected to an RC network or a crystal

(by mask option) for the internal system clock. In the case of RC

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

RES

Schmitt trigger reset input, active low

HT49C50

August 18, 1999

HT49C50 Datasheet(PDF) 6 Page - Holtek Semiconductor Inc

HT49C50 Datasheet(HTML) 6 Page - Holtek Semiconductor Inc

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