PD2435 Datasheet, PDF (7/11 Pages) OSRAM GmbH – 4-Character 5 x 7 Dot Matrix Alphanumeric Programmable Display™ with Built-in CMOS Control Functions

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.
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)
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.
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.
D7 D6 D5 D4 D3 D2 D1 D0 Operation
0 0 X X X X 0 0 Blank
0 0 X X X X 0 1 25% brightness
0 0 X X X X 1 0 50% brightness
0 0 X X X X 1 1 Full 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.
Control Word Format
D7
Clear
D6
Lamp
test
D5
Blink
D4
Attribute
enable
D3
D2
Attributes
D1
D0
Brightness
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%
D4 Attribute enable
0 Disable above Attributes
1 Enable above Attributes
D5 Blink
0 Blink Attribute Disabled
1 Blink Entire Display
D6 Lamp test
0 Standard Operation
1 Display All Dots at 50% Brightness
D7 Clear
0 Standard Operation
1 Clear Entire Display
 2001 OSRAM Opto Semiconductors Inc.• San Jose, CA
www.infineon.com/opto • 408-456-4000
OSRAM Opto Semiconductors GmbH & Co. OHG • Regensburg, Germany
www.osram-os.com • [phone]
7
PD2535/6/7, PD3535/6/7, PD4435/6/7
July 5, 2001-14