 2001 OSRAM Opto Semiconductors Inc.• San Jose, CA

PD2535/6/7, PD3535/6/7, PD4435/6/7

www.infineon.com/opto • 408-456-4000

OSRAM Opto Semiconductors GmbH & Co. OHG • Regensburg, Germany

www.osram-os.com • +49-941-202-7178

7

July 5, 2001-14

There are five registers within the display. Four of these regis-

ters are used to hold the ASCII/attribute code of the four dis-

play characters. The fifth register is the Control Word, which is

used to blink, blank, clear, or dim the entire display, or to

change the presentation (attributes) of individual characters.

Addressing

The addresses within the display device are shown below. Digit

0 is the rightmost digit of the display, while digit 3 is on the left.

Although there is only one Control Word, it is duplicated at the

four address locations 0–3. Data can be read from any of these

locations. When one of these locations is written to, all of them

will change together.

Bit D7 of any of the display digit locations is used to allow an

attribute to be assigned to that digit. The attributes are dis-

cussed in the next section. If Bit D7 is set to a one, that charac-

ter will be displayed using the attribute. If bit D7 is cleared, the

character will display normally.

Address

Contents

A2

A1

A0

0

X

X

Control Word

1

0

0

Digit 0 (rightmost)

1

0

1

Digit 1

1

1

0

Digit 2

1

1

1

Digit 3 (leftmost)

Control Word

When address bit A2 is taken low, the Control Word is

accessed. The same Control Word appears in all four of the

lower address spaces of the display. Through the Control Word,

the display can be cleared, the lamps can be tested, display

brightness can be selected, and attributes can be set for any

characters which have been loaded with their most significant

bit (D7) set high.

Brightness (D0, D1): The state of the lower two bits of the

Control Word are used to set the brightness of the entire dis-

play, from 0% to 100%. The table below shows the correspon-

dence of these bits to the brightness.

X=don't care

Attributes (D2–D4): Bits D2, D3, and D4 control the visual

attributes (i.e., blinking) of those display digits which have been

written with bit D7 set high. In order to use any of the four

attributes, the Cursor Enable bit (D4 in the Control Word) must

be set. When the Cursor Enable bit is set, and bit D7 in a char-

acter location is set, the character will take on one of the fol-

lowing display attributes.

D7

D6

D5

D4

D3

D2

D1

D0

Operation

0

0

XXXX0

0

Blank

0

0

XXXX0

1

25% brightness

0

0

XXXX1

0

50% brightness

0

0

XXXX1

1

Full brightness

Control Word Format

D7

D6

D5

D4

D3

D2

D1

D0

Clear

Blink

Attributes

Brightness

Lamp

test

Attribute

enable

D7 Clear

0

Standard Operation

1

Clear Entire Display

D6 Lamp test

0

Standard Operation

1

Display All Dots at 50% Brightness

D5 Blink

0

Blink Attribute Disabled

1

Blink Entire Display

D4 Attribute enable

0

Disable above Attributes

1

Enable above Attributes

D3 D2 Attributes

0

0

Display Cursor instead

of Character

0

1

Blink Character

1

0

Display Blinking Cursor

instead of Character

1

1

Alternate Character

with Cursor

D1 D0 Brightness

0

0

0% (blank)

0

1

25%

1

0

50%

1

1

100%