pcf8534 NXP Semiconductors, pcf8534 Datasheet - Page 17

• Manufacturer Part Number: pcf8534
• Description: Universal Driver Multiplex Rates
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCF8534_0
Preliminary datasheet
6.14 Input bank selector
6.15 Blinker
The input bank selector loads display data into the display RAM in accordance with the
selected LCD drive configuration. Display data can be loaded in bit 2 in static drive mode
or in bits 2 and 3 in 1:2 drive mode by using the BANK SELECT command. The input
bank selector functions independently to the output bank selector.
The display blinking capabilities of the PCF8534 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, see
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 is 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 7.
Blinking mode
Off
2 Hz
1 Hz
0.5 Hz
Blinking frequencies
Rev. 00.05 — 20 February 2007
-
Normal operating mode
ratio
----------- -
1536
f
f
----------- -
3072
f
---------- -
CLK
768
CLK
CLK
Universal LCD driver for low multiplex rates
Normal blinking frequency
Blinking off
2 Hz
1 Hz
0.5 Hz
PCF8534
Table
© NXP B.V. 2007. All rights reserved.
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