TC826 データシートの表示（PDF） - Microchip Technology

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TC826

Analog-to-Digital Converter with Bar Graph Display Output

Microchip Technology 

4.14 BAR Format

The TC826 powers up in the BAR mode. BAR/DOT is

pulled high internally. This display format is similar to a

thermometer display. All bars/LCD segments including

zero, below the bar/LCD segment equaling the input

signal level, are on. A half scale input signal, for exam-

ple, would be displayed with BAR 0 to BAR 20 on.

4.15 DOT Format

By connecting BAR/DOT to VSS through a 1MΩ resis-

tor, the DOT mode is selected. Only the BAR LCD seg-

ment equaling the input signal is on. The zero segment

is on for zero input.

This mode is useful for moving cursor or ‘needle’ appli-

cations.

4.16 LCD Displays

Most end products will use a custom LCD display for

final production. Custom LCD displays are low cost and

available from all manufacturers. The TC826 interfaces

to non-multiplexed LCD displays. A backplane driver is

included on-chip.

To speed initial evaluation and prototype work, a stan-

dard TC826 LCD display is available from Varitronix.

Varitronix Ltd. LCDs

4/F Liven House

61-63 King Yip Street

Kwun Tong, Kowloon

Hong Kong

Tel: (852)2389-4317

Fax: (852)2343-9555

USA Office:

VL Electronics / Varitronix

3250 Wilshire Blvd., Suite 901

Los Angeles, CA 90010

Tel: (213) 738-8700

Fax: (213) 738-5340

• Part No.: VBG-413-DP

Other standard LCD displays suitable for development

work are available in both linear and circular formats.

One manufacturer is:

UCE Inc.

24 Fitch Street

Norwalk, CT 06855

Tel: 203/838-7509

• Part No. 5040: 50 segment circular display with

3-digit numeric scale.

• Part No. 5020: 50 segment linear display.

TC826

4.17 LCD Backplane Driver (BP, Pin 15)

Additional drive electronics are not required to interface

the TC826 to an LCD display. The TC826 has an on-

chip backplane generator and driver. The backplane

frequency is:

FBP = FOSC/256

Figure 4-8 gives typical backplane driver rise/fall time

versus backplane capacitance.

FIGURE 4-8:

BACKPLANE DRIVE RISE/

FALL TIME VS.

CAPACITANCE

10

9 TA = 25°C

8 VS = 9V

7

6

5

4

3

2

1

0 1 2 3 4 5 6 7 8 0 10

Backplane Capacitance (X 100pf)

4.18 Flat Package Socket

Sockets suitable for prototype work are available. A

USA source is:

Nepenthe Distribution

2471 East Bayshore, Suite 520

Palo Alto, CA 94303

Tel: 415/856-9332

Telex: 910/373-2060

• ‘BQ’ Socket Part No.: IC51-064-042 BQ

© 2002 Microchip Technology Inc.

DS21477B-page 13

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