 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

8

July 5, 2001-14

*“Cursor”= all dots in a single character space lit to half brightness

X=Don't care

B=Depends on the selected brightness.

Attributes are non-destructive. If a character with bit D7 set is

replaced by a cursor (Control Word bit D4 is set, and D3=D2=0)

the character will remain in memory and can be revealed again

by clearing D4 in the Control Word.

Blink (D5): The entire display can be caused to blink at a rate of

approximately 2.0 Hz by setting bit D5 in the Control Word. This

blinking is independent of the state of D7 in all character locations.

To synchronize the blink rate in a bank of these devices, it is

necessary to tie all devices' clocks and resets together as

described in a later section of this data sheet.

D7

D6

D5

D4

D3

D2

D1

D0

Operation

0000X

X

B

B

Disable highlight

attribute

000100B

B

Display cursor*

instead of

character

000101B

B

Blink single

character

000110B

B

Display blinking

cursor* instead

of character

000111B

B

Alternate charac-

ter with cursor*

Lamp Test (D6): When the Lamp Test bit is set, all dots in the

entire display are lit at half brightness. When this bit is cleared,

the display returns to the characters that were showing before

the lamp test.

Clear Data (D7): When D7 is set (D7=1) in the Control Word, all

(display) memory bits are reset to zero and the display goes blank.

A second control word must be written into the chip with D7

reset (D7=0) to set up attributes and brightness levels.

The SMC-4740 oscillator is designed to drive up to 16 displays

with input loading of 15 pF each.

The general requirements for cascading 16 displays are:

1. Determine the correct address for each display.

2. Tie CE0 to ground and use CE1 from an address.

3. Select one of the displays to provide the clock for the

other displays.

4. Tie CLKSEL to ground on other displays.

5. Use RST to synchronize the blinking between the displays.

D7

D6

D5

D4

D3

D2

D1

D0

Operation

0

0

1

X

X

X

B

B

Blinking display

D7

D6

D5

D4

D3

D2

D1

D0

Operation

0

1

0

XXXXX

Lamp test

D7

D6

D5

D4

D3

D2

D1

D0

Operation

1

0

XXXXXX

Clear

Figure 6. Cascading Diagram

WR

RD

RST CLK I/O CLKSEL

D0-D7 A0-A2

CE0

CE1

Programmable Display

WR

RD

RST CLK I/O CLKSEL

D0-D7 A0-A2

CE0

CE1

Programmable Display

14 More Displays

in between

Address Decode Chip 1 to 14

Address

Data I/O

RST

RD

WR

A4

A5

A6

Address

Decoder