Datasheet

PD243X, PD353X, PD443X
2006-01-23 9
There are five registers within the display. Four of these registers
are used to hold the ASCII/attribute code of the four display char-
acters. The fifth register is the Control Word, which is used to blink,
blank, clear, or dim the entire display, or to change the presenta-
tion (attributes) of individual characters.
Adressing
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 loca-
tions. 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 at-
tribute to be assigned to that digit. The attributes are discussed in
the next section. If Bit D7 is set to a one, that character will be dis-
played using the attribute. If bit D7 is cleared, the character will dis-
play 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 display, from 0%
to 100%. The table below shows the correspondence of these bits
to the brightness.
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 character
location is set, the character will take on one of the following dis-
play attributes.
Control Word Format
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)
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
IDCW5163
Enable
Attribute
Blink
Test
Lamp
Clear Attributes Brightness
D7 D6 D5 D4 D3 D2 D1 D0
D1 D0 Brightness
0% (blank)00
25%01
1 50%0
1 100%1
Attributes
Display cursor instead
1
0
0
D3
0 Display blinking cursor
of character
Blink character
0
1
D2
instead of character
1
with cursor
Alternate character1
Disable above attributes
Attribute EnableD4
0
Enable above attributes1
Blink entire display
Blink attribute disabled
Blink
D5
1
0
Standard operation
1
D6
0
Display all dots at 50% brightness
Lamp Test
Clear entire display
Standard operation0
1
ClearD7