
2002 Microchip Technology Inc.
DS21474B-page 5
TC815
2.0
PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 2-1.
TABLE 2-1:
PIN FUNCTION TABLE
Pin Number
(64-Pin Plastic)
Quad Flat Package
Symbol
Description
1
2
3
4
NC
OHM
20mA
BUZ
Logic Input. “0” (Digital Ground) for resistance measurement.
Logic Input. “0” (Digital Ground) for 20mA full scale current measurement.
Audio frequency, 4kHz, output for continuity indication during resistance measurement.
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.
32.768kHz Crystal Connection.
32.768kHz Crystal Connection.
Sets peak LCD drive signal: V
P
- V
DD
- V
DISP
. V
DISP
may also be used to compensate for
temperature variation of LCD crystal threshold voltage.
LCD Backplane #1.
LCD Backplane #2.
LCD Backplane #3.
LCD Annunciator segment drive for low ohms resistance measurement and current
measurement.
LCD Annunciator segment drive for resistance measurement and voltage measurement.
LCD Annunciator segment drive for k (“kilo-ohms”), m (“milliamps” and
“millivolts”) and HOLD mode.
LCD segment drive for “b,” “c” segments and decimal point of least significant digit (LSD).
5
6
7
XTAL1
XTAL2
V
DISP
8
9
10
11
BP1
BP2
BP3
LO
/A
12
13
/V
k/m/HOLD
14
BCP0
(One’s digit)
ADG0
FE0
NC
BCP1
AGD1
FE1
BCP2
15
16
17
18
19
20
21
LCD segment drive for “a,” “g,” “d” segments of LSD.
LCD segment drive for “f” and “e” segments of LSD.
No connection.
LCD segment drive for “b,” “c” segments and decimal point of 2nd LSD.
LCD segment drive for “a,” “g,” “d” segments of 2nd LSD (Ten’s digit).
LCD segment drive for “f” and “e” segments of 2nd LSD.
LCD segment drive for “b,” “c” segments and decimal point of 3rd LSD
(Hundred’s digit).
LCD segment drive for “a,” “g,” “d” segments of 3rd LSD.
LCD segment drive for “b,” “c” segments and decimal point of 3rd LSD.
LCD segment drive for “b,” “c” segments and decimal point of MSD
(Thousand’s digit).
LCD annunciator drive signal for AC measurements, polarity, and auto-range operation.
LCD annunciator drive signal for low battery indication and Memory
(Relative Measurement) mode.
Negative battery supply connection for internal digital circuits. Connect to negative terminal
of battery.
Positive battery supply connection.
Analog circuit ground reference point. Nominally 2.6V below V
CC
.
22
23
24
AGD2
FE2
BCP3
25
26
AC/-/AUTO
-MEM/BATT
27
V
SSD
28
29
V
CC
ANALOG
COM
RM
REFH
RM
REFL
C
REFL
C
REFH
REFHI
30
31
32
33
34
Ratiometric (Resistance measurement) reference high voltage.
Ratiometric (Resistance measurement) reference low voltage.
Reference capacitor negative terminal C
REF
0.1μf.
Reference capacitor positive terminal C
REF
0.1μf.
Reference voltage for voltage and current measurement; nominally 163.85mV.