PCF8576D Datasheet, PDF (18/41 Pages) NXP Semiconductors – Universal LCD driver for low multiplex rates

Philips Semiconductors
Universal LCD driver for low
multiplex rates
Product specification
PCF8576D
6.14 Input bank selector
The input bank selector loads display data into the display
RAM in accordance with the selected LCD drive
configuration. The BANK SELECT command can be used
to load display data in bit 2 in static drive mode or in
bits 2 and 3 in 1 : 2 mode. The input bank selector
functions are independent of the output bank selector.
6.15 Blinker
The PCF8576D has a very versatile display blinking
capability. The whole display can blink at a frequency
selected by the BLINK command. Each blink frequency is
a multiple integer value of the clock frequency; the ratio
between the clock frequency and blink frequency depends
on the blink mode selected, as shown in Table 3.
An additional feature allows an arbitrary selection of LCD
segments to be blinked in the static and 1 : 2 drive modes.
This is implemented without any communication
overheads by the output bank selector which alternates
the displayed data between the data in the display RAM
bank and the data in an alternative RAM bank at the blink
frequency. This mode can also be implemented by the
BLINK command.
In the 1 : 3 and 1 : 4 drive modes, where no alternative
RAM bank is available, groups of LCD segments can be
blinked by selectively changing the display RAM data at
fixed time intervals.
The entire display can be blinked at a frequency other than
the nominal blink frequency by sequentially resetting and
setting the display enable bit E at the required rate using
the MODE SET command.
Table 3 Blinking frequencies
Off
2 Hz
BLINK MODE
1 Hz
0.5 Hz
NORMAL OPERATING MODE
RATIO
−
-f7-^C---6-^L--8-^K-
1--f-^C-5---L3---^K-6-
3--f-^C-0---L7---^K-2-
NOMINAL BLINK FREQUENCY
blinking off
2 Hz
1 Hz
0.5 Hz
Note
1. Blink modes 0.5, 1 and 2 Hz, and nominal blink frequencies 0.5, 1 and 2 Hz correspond to an oscillator frequency
(f_CLK) of 1536 Hz at pin CLK. The oscillator frequency range is given in Chapter 11.
2004 Dec 22
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