© 2002 Microchip Technology Inc.

DS21474B-page 5

TC815

2.0

PIN DESCRIPTIONS

Thedescriptionsof the pins arelistedinTable2-1.

TABLE 2-1:

PIN FUNCTION TABLE

Pin Number

(64-Pin Plastic)

Quad Flat Package

Symbol

Description

1

NC

Logic Input. “0” (Digital Ground) for resistance measurement.

2OHM

Logic Input. “0” (Digital Ground) for 20mA full scale current measurement.

320mA

Audio frequency, 4kHz, output for continuity indication during resistance measurement.

4

BUZ

Audio frequency, 4kHz, output for continuity indication during resistance measurement. A

non-continuous 4kHz signal is output to indicate an input overrange during voltage or

current measurements.

5

XTAL1

32.768kHz Crystal Connection.

6

XTAL2

32.768kHz Crystal Connection.

temperature variation of LCD crystal threshold voltage.

8

BP1

LCD Backplane #1.

9

BP2

LCD Backplane #2.

10

BP3

LCD Backplane #3.

11

LO

Ω/A

LCD Annunciator segment drive for low ohms resistance measurement and current

measurement.

12

Ω/V

LCD Annunciator segment drive for resistance measurement and voltage measurement.

13

k/m/HOLD

LCD Annunciator segment drive for k (“kilo-ohms”), m (“milliamps” and

“millivolts”) and HOLD mode.

14

BCP0

(One’s digit)

LCD segment drive for “b,” “c” segments and decimal point of least significant digit (LSD).

15

ADG0

LCD segment drive for “a,” “g,” “d” segments of LSD.

16

FE0

LCD segment drive for “f” and “e” segments of LSD.

17

NC

No connection.

18

BCP1

LCD segment drive for “b,” “c” segments and decimal point of 2nd LSD.

19

AGD1

LCD segment drive for “a,” “g,” “d” segments of 2nd LSD (Ten’s digit).

20

FE1

LCD segment drive for “f” and “e” segments of 2nd LSD.

21

BCP2

LCD segment drive for “b,” “c” segments and decimal point of 3rd LSD

(Hundred’s digit).

22

AGD2

LCD segment drive for “a,” “g,” “d” segments of 3rd LSD.

23

FE2

LCD segment drive for “b,” “c” segments and decimal point of 3rd LSD.

24

BCP3

LCD segment drive for “b,” “c” segments and decimal point of MSD

(Thousand’s digit).

25

AC/-/AUTO

LCD annunciator drive signal for AC measurements, polarity, and auto-range operation.

26

-MEM/BATT

LCD annunciator drive signal for low battery indication and Memory

(Relative Measurement) mode.

27

Negative battery supply connection for internal digital circuits. Connect to negative terminal

of battery.

28

Positive battery supply connection.

29

ANALOG

COM

30

Ratiometric (Resistance measurement) reference high voltage.

31

Ratiometric (Resistance measurement) reference low voltage.

32

33

34

REFHI

Reference voltage for voltage and current measurement; nominally 163.85mV.