TC820CPL Просмотр технического описания (PDF) - Microchip Technology
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TC820CPL Datasheet PDF : 28 Pages
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TC820
2.0 PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 2-1.
TABLE 2-1: PIN FUNCTION TABLE
Pin Number Pin Number
(40-PDIP) (44-PQFP)
Symbol
Description
1
40
L-E4 LCD segment driver for L ("logic LOW"), polarity, and "e" segment of most significant
digit (MSD).
2
41
AGD4 LCD segment drive for "a," "g," and "d" segments of MSD.
3
42
BC4P3 LCD segment drive for "b" and "c" segments of MSD and decimal point 3.
4
43
HFE3 LCD segment drive for H ("logic HIGH"), and "f" and "e" segments of third LSD.
5
44
AGD3 LCD segment drive for "a," "g," and "d" segments of third LSD.
6
1
BC3P2 LCD segment drive for "b" and "c" segments of third LSD and decimal point 2.
7
2
OFE2 LCD segment drive for "over range," and "f" and "e" segments of second LSD.
8
3
AGD2 LCD segment drive for "a," "g," and "d" segments of second LSD.
9
4
BC2P1 LCD segment drive for "b " and "c" segments of second LSD and decimal point 1.
10
5
PKFE1 LCD segment drive for "hold peak reading," and "f" and "e" segments of LSD.
11
6
AGD1 LCD segment drive for "a," "g," and "d" segments of LSD.
12
7
BC1BT LCD segment drive for "b" and "c" segments of LSD and "low battery."
13
8
BP3 LCD backplane #3.
14
9
BP2 LCD backplane #2.
15
10
BP1 LCD backplane #1.
—
11
VDISP Sets peak LCD drive signal: VPEAK = (VDD) – VDISP. VDISP may also be used to
compensate for temperature variation of LCD crystal threshold voltage.
16
12
DGND Internal logic digital ground, the logic "0" level. Nominally 4.7V below VDD.
17
13
ANNUNC Square-wave output at the backplane frequency, synchronized to BP1. ANNUNC can be
used to control display annunciators. Connecting an LCD segment to ANNUNC turns it
on; connecting it to its backplane turns it off.
18
14
LOGIC Logic mode control input. When connected to VDD, the converter is in Logic mode. The
LCD displays "OL" and the decimal point inputs control the HIGH and LOW annunciators.
When the "low" annunciator is on, the buzzer will also be on. When unconnected or con-
nected to DGND, the TC820 is in the Voltage/Frequency Measurement mode. This pin
has a 5µA internal pull-down to DGND.
19
15
RANGE/ Dual purpose input. In Range mode, when connected to VDD, the integration time
FREQ will be 200 counts instead of 2000 counts
20
16
DP0/LO Dual purpose input. Decimal point select input for voltage measurements. In logic mode,
connecting this pin to VDD will turn on the "low" LCD segment. There is an internal 5µA
pull-down to DGND in Volts mode only. Decimal point logic:
DP1
DPQ
Decimal Point Selected
0
0
None
0
1
DP1
1
0
DP2
1
1
DP3
21
17
DP1/HI Dual purpose input. Decimal point select input for voltage measurements. In Logic mode,
connecting this pin to VDD will turn on the "high" LCD segment. There is an internal 5µA
pull-down to DGND in Volts mode only.
22
18
BUZOUT Buzzer output. Audio frequency, 5kHz, output which drives a piezoelectric buzzer.
23
19
BUZIN Buzzer control input. Connecting BUZIN to VDD turns the buzzer on. BUZIN is logically
OR’ed (internally) with the "logic level low" input. There is an internal 5µA pull-down to
DGND.
24
20
FREQ/ Voltage or frequency measurement select input. When unconnected, or connected
VOLTS VOLTS to DGND, the A/D converter function is active. When connected to VDD, the
frequency counter function is active. This pin has an internal 5µA pull-down to DGND.
DS21476B-page 6
© 2002 Microchip Technology Inc.
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