Pad Description

Pad No.

Pad Name

I/O

Function

1

LOWC

B

For the supply voltage detector, open the pin when not in use.

2

VSS

I

Power supply GND

3

SC

B

Common point, NMOS open drain

4

RF

O

Connect reference resistor, PMOS open drain

5

RS

O

Connect sensor resistor, PMOS open drain

6

VDD

¾

Positive power supply

7

PSW

I

Pull-low input pin, push switch to turn power on or off

8

TEST2

I

Pull-low test pin, for production test, floating LCD displays

the real time value, when connected to VDD, LCD displays

the highest value.

9

CLFH

I

Floating for °C, connect to VDD for °F

10

OSCI

I

For system oscillator in

11

OSCO

O

For system oscillator out

12

BZ1

O

Buzzer output 1

13

BZ2

O

Buzzer output 2

14~16

COM1~COM3

O

LCD backplane drive, 3-level voltage out

17~19

SA1~SA3

O

LCD segment drive

20~22

SB1~SB3

O

LCD segment drive

23~25

SC1~SC3

O

LCD segment drive

26

SD1

O

LCD segment drive

27

VEE

O

Generate negative voltage (-1.5V)

28

CAP

O

For negative voltage, NMOS output

29

C512

O

For negative voltage, inverter output

30

TV

B

Test pin for IC

31

TEST1

I

Test pin for IC

32

TIM

I

Test pin for IC

33

TS816

I

Test pin for IC

HT7500

3

August 8, 2000