OM4085 Philips Semiconductors, OM4085 Datasheet - Page 5

• Manufacturer Part Number: OM4085
• Description: Universal LCD driver for low multiplex rates
• Manufacturer: Philips Semiconductors

Philips Semiconductors
FUNCTIONAL DESCRIPTION
The OM4085 is a versatile peripheral device designed to
interface any microprocessor to a wide variety of LCDs.
It can directly drive any static or multiplexed LCD
containing up to 4 backplanes and up to 24 segments.
The display configurations possible with the OM4085
depend on the number of active backplane outputs
required; a selection of display configurations is given in
Table 1.
Table 1
1997 Feb 25
handbook, full pagewidth
BACKPLANE
Universal LCD driver for low multiplex
rates
OUTPUTS
ACTIVE
4
3
2
1
Selection of display configurations
V DD
V SS
NUMBER OF
SEGMENTS
CONTROLLER
PROCESSOR/
MICRO-
MICRO-
HOST
96
72
48
24
R
2 C bus
t rise
7-SEGMENT NUMERIC
12 digits + 12 indicator
symbols
9 digits + 9 indicator
symbols
6 digits + 6 indicator
symbols
3 digits + 3 indicator
symbols
Fig.3 Typical system configuration.
OSC
SDA
SCL
1
2
6
7
A0
5
V DD
8
A1
OM4085
5
9
All of the display configurations given in Table 1 can be
implemented in the typical system shown in Fig.3.
The host microprocessor/microcontroller maintains the
two-line I
OM4085. The internal oscillator is selected by tying OSC
(pin 6) to V
multiplexed LCD waveforms are generated internally.
The only other connections required to complete the
system are to the power supplies (V
to the LCD panel chosen for the application.
A2
12
6 characters + 12 indicator
symbols
4 characters + 16 indicator
symbols
3 characters + 6 indicator
symbols
1 character + 10 indicator
symbols
V LCD
10
17 to 40
13 to 16
SA0
11
ALPHANUMERIC
V SS
2
C-bus communication channel with the
14-SEGMENT
24 segment drives
SS
4 backplanes
. The appropriate biasing voltages for the
LCD PANEL
(up to 96
elements)
MBH951
96 dots (4
72 dots (3
48 dots (2
24 dots
DD
Product specification
, V
DOT MATRIX
SS
OM4085
and V
24)
24)
24)
LCD
) and