pcf8534a NXP Semiconductors, pcf8534a Datasheet - Page 6

• Manufacturer Part Number: pcf8534a
• Description: Universal Lcd Driver For Low Multiplex Rates
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCF8534A_3
Product data sheet
7.1 Power-on reset
7.2 LCD bias generator
7.3 LCD voltage selector
The host microprocessor or microcontroller maintains the 2-line I
channel with the PCF8534A.
Biasing voltages for the multiplexed LCD waveforms are generated internally, removing
the need for an external bias generator. The internal oscillator is selected by connecting
pin OSC to V
power supplies (pins V
At power-on the PCF8534A resets to a default starting condition:
Do not transfer data on the I
complete.
Fractional LCD biasing voltages are obtained from an internal voltage divider comprising
three series resistors connected between pins V
switched out of the circuit to provide the
configuration.
The LCD voltage selector coordinates the multiplexing of the LCD based on the selected
LCD drive configuration. The operation of the voltage selector is controlled by mode set
commands from the command decoder.
Fig 4.
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All backplane outputs are set to V
All segment outputs are set to V
The selected drive mode is: 1:4 multiplex with
Blinking is switched off
Input and output bank selectors are reset
The I
The data pointer and the subaddress counter are cleared (set to logic 0)
The display is disabled
V
V
DD
SS
2
Typical system configuration
C-bus interface is initialized
CONTROLLER
PROCESSOR/
MICRO-
MICRO-
SS
HOST
. The only other connections required to complete the system are the
R
2C
Rev. 03 — 10 November 2008
t
r
b
DD
, V
SS
2
C-bus after a power-on for 1 ms to enable the reset action to
and V
OSC
SDA
SCL
LCD
LCD
LCD
A0
) and the LCD panel selected for the application.
1
2
PCF8534A
Universal LCD driver for low multiplex rates
bias voltage level for the 1:2 multiplex
A1
V
DD
A2
LCD
V
1
LCD
SA0
3
and V
bias
V
SS
60 segment drives
SS
4 backplanes
. The center resistor is
2
C-bus communication
PCF8534A
© NXP B.V. 2008. All rights reserved.
LCD PANEL
(up to 240
elements)
001aah616
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