SCDQ5541P/Q/R, SCDQ5542P/Q/R, SCDQ5543P/Q/R, SCDQ5544P/Q/R

2010-04-13

10

Row Strobe Example

The user can activate four Control functions. These include: LED

Brightness Level, Lamp Test, IC Power Down, or Display Clear.

OPCODEs and five bit words are used to initiate these functions.

The OPCODEs and Control Words for the Character Address and

Loading Column Data are shown in Instruction Set Table.

The user can select seven specific LED brightness levels. These

brightness levels (in percentages of full brightness of the display)

include: 100% (F0HEX), 53% (F1HEX), 40% (F2HEX), 27%

(F3HEX), 20% (F4HEX), 13% (F5HEX), and 6.6% (F6HEX). The

brightness levels are controlled by changing the duty factor of the

row strobe pulse.

The SCDQ554X offers a unique Display Power Down feature

which reduces I

display is set to 0% brightness and the internal multiplex clock is

stopped. When in the Power Down mode data may still be written

into the RAM. The display is reactivated by loading a new right-

ness Level Control Word into the display.

The Lamp Test is enabled by loading F8HEX into the serial shift

register. This Control Word sets all of the LEDs to a 53% bright-

ness level. Operation of the Lamp Test has no affect on the RAM

and is cleared by loading a Brightness Control Word.

The Software Clear (C0HEX) clears the Address Register and the

RAM. The display is blanked and the Character Address Register

will be set to Character 0. The internal counter and the Control

Word Register are unaffected. The Software Clear will remain

active until the next data input cycle is initiated.

Electrical & Mechanical Considerations

Interconnect Considerations

Optimum product performance can be had when the following

electrical and mechanical recommendations are adopted. The

SCDQ554XX’s IC is constructed in a high speed CMOS process,

consequently high speed noise on the SERIAL DATA, SERIAL

DATA CLOCK, and LOAD lines may cause incorrect data to be

written into the serial shift register. Adhere to transmission line ter-

mination procedures when using fast line drivers and long cables

(>10 cm).

Good digital grounds (pin 1) and power supply decoupling (pin 2)

will insure that I

erate localized ground bounce. Therefore it is recommended that

each display package use a 0.1 µF and 20 µF capacitor between

V

IDXX5182

Row 0

Row 1

Row 2

Row 3

Row 4

01 2 3 4

Columns

Load Row 0

Load

4

Row 4

Columns

1

0

2 3

Row 3

Row 1

Row 0

Row 2

Load Row 1

Columns

Row 4

1

0

2

4

3

Load Row 2

Row 2

Row 1

Row 3

Row 0

Row 4

0

Columns

2

13 4

Load Row 3

Row 0

Row 3

Row 1

Row 2

Row 4

Columns

01 2

4

3

Row 2

Row 1

Row 3

Row 0

Load Row 4

Row

Display Brightness

Op code

D7 D6 D5

Control Word

D4

D3

D2

D1

D0

Hex

Operation

Level

11

1

10

0

0

0

F0

100%

11

1

10

0

0

1

F1

53%

11

1

10

0

1

0

F2

40%

11

1

10

0

1

1

F3

27%

11

1

10

1

0

0

F4

20%

11

1

10

1

0

1

F5

13%

11

1

10

1

1

0

F6

6.6%

Power Down

Op code

D7 D6 D5

Control Word

D4

D3

D2

D1

D0

Hex

Operation

Level

11

1

11

1

1

1

FF

0%

brightness

Lamp Test

Op code

D7 D6 D5

Control Word

D4

D3

D2

D1

D0

Hex

Operation

Level

11

1

10

B

B

B

Lamp Test

(OFF)

11

1

11

0

0

0

F8

Lamp Test

(ON)

Software Clear

Op code

D7 D6 D5

Control Word

D4

D3

D2

D1

D0

Hex

Operation

Level

11

0

00

0

0

0

C0

CLEAR