1998 Jul 30
18
Philips Semiconductors
Product specication
Universal LCD driver for low multiplex
rates
PCF8576C
6.16
Blinker
The display blinking capabilities of the PCF8576C are very
versatile. The whole display can be blinked at frequencies
selected by the BLINK command. The blinking frequencies
are integer multiples of the clock frequency; the ratios
between the clock and blinking frequencies depend on the
mode in which the device is operating, as shown in
Table 4.
An additional feature is for an arbitrary selection of LCD
segments to be blinked. This applies to the static and
1 : 2 LCD drive modes and can be implemented without
any communication overheads.
By means of the output bank selector, the displayed RAM
banks are exchanged with alternate RAM banks at the
blinking frequency. This mode can also be specified by the
BLINK command.
In the 1 : 3 and 1 : 4 multiplex modes, where no alternate
RAM bank is available, groups of LCD segments can be
blinked by selectively changing the display RAM data at
fixed time intervals.
If the entire display is to be blinked at a frequency other
than the nominal blinking frequency, this can be effectively
performed by resetting and setting the display enable bit E
at the required rate using the MODE SET command.
Table 4
Blinking frequencies
BLINKING MODE
NORMAL OPERATING
MODE RATIO
POWER-SAVING MODE
RATIO
NOMINAL BLINKING
FREQUENCY
Off
blinking off
2Hz
1Hz
0.5 Hz
f
clk
92160
----------------
f
clk
15360
----------------
f
clk
184320
--------------------
f
clk
30720
----------------
f
clk
368640
--------------------
f
clk
61440
----------------