Philips Semiconductors
Product specification
Universal LCD driver for low multiplex
rates
PCF8576
The host microprocessor/microcontroller maintains the
2-line I2C-bus communication channel with the PCF8576.
The internal oscillator is selected by connecting pin OSC
to pin VSS. The appropriate biasing voltages for the
multiplexed LCD waveforms are generated internally.
The only other connections required to complete the
system are to the power supplies (VDD, VSS and VLCD) and
the LCD panel chosen for the application.
6
FUNCTIONAL DESCRIPTION
The PCF8576 is a versatile peripheral device designed to
interface to any microprocessor/microcontroller to a wide
variety of LCDs. It can directly drive any static or
multiplexed LCD containing up to four backplanes and up
to 40 segments. The display configurations possible with
the PCF8576 depend on the number of active backplane
outputs required; a selection of display configurations is
given in Table 1.
All of the display configurations given in Table 1 can be
implemented in the typical system shown in Fig.3.
Table 1 Selection of display configurations
14-SEGMENTS
ALPHANUMERIC
NUMBER OF
7-SEGMENTS NUMERIC
DOT MATRIX
INDICATOR
SYMBOLS
INDICATOR
SYMBOLS
BACKPLANES SEGMENTS
DIGITS
CHARACTERS
4
3
2
1
160
120
80
20
15
10
5
20
15
10
5
10
8
20
8
160 dots (4 × 40)
120 dots (3 × 40)
80 dots (2 × 40)
40 dots (1 × 40)
5
10
12
40
2
handbook, full pagewidth
V
DD
t
r
R
2C
B
V
V
DD
LCD
5
12
SDA
SCL
OSC
HOST
MICRO-
1
2
6
17 to 56 40 segment drives
LCD PANEL
PROCESSOR/
MICRO-
CONTROLLER
PCF8576
(up to 160
elements)
4 backplanes
13 to 16
10 11
A0 A1 A2 SA0 V
7
8
9
R
MBK277
OSC
SS
V
SS
Fig.3 Typical system configuration.
7
1998 Feb 06
NXP [ NXP ]
