PCF8576C View Datasheet(PDF) - NXP Semiconductors.
Part Name
Description
MFG CO.
'PCF8576C' PDF : 57 Pages View PDF
NXP Semiconductors
PCF8576C
Universal LCD driver for low multiplex rates
7.14 Bank selector
7.14.1 Output bank selector
The output bank selector (see Table 12), selects one of the four rows per display RAM
address for transfer to the display register. The actual row selected depends on the LCD
drive mode in operation and on the instant in the multiplex sequence.
• In 1:4 multiplex mode: all RAM addresses of row 0 are selected, followed sequentially
by the contents of row 1, row 2, and then row 3.
• In 1:3 multiplex mode: rows 0, 1, and 2 are selected sequentially.
• In 1:2 multiplex mode: rows 0 and 1 are selected.
• In the static mode: row 0 is selected.
The PCF8576C includes a RAM bank switching feature in the static and 1:2 multiplex
drive modes. In the static drive mode, the bank-select command may request the contents
of row 2 to be selected for display instead of the contents of row 0. In 1:2 multiplex drive
mode, the contents of rows 2 and 3 may be selected instead of rows 0 and 1. This
enables preparation of display information in an alternative bank and the ability to switch
to it once it has been assembled.
7.14.2 Input bank selector
The input bank selector (see Table 12) loads display data into the display RAM based on
the selected LCD drive configuration. Using the bank-select command, display data can
be loaded in row 2 into static drive mode or in rows 2 and 3 into 1:2 multiplex drive mode.
The input bank selector functions independently of the output bank selector.
7.15 Blinker
The display blinking capabilities of the PCF8576C are very versatile. The whole display
can be blinked at frequencies selected by the blink-select command. The blinking
frequencies are integer fractions of the clock frequency; the ratios between the clock and
blinking frequencies depend on the mode in which the device is operating (see Table 7).
Table 7. Blink frequencies
Blinking mode
off
1
Normal-power mode
ratio
-
fblink
=
-----f--c--l--k-----
92160
2
fblink
=
------f--c---l-k-------
184320
3
fblink
=
------f--c---l-k-------
368640
Power-saving mode
ratio
-
fblink
=
-----f--c--l--k-----
15360
fblink
=
-----f--c--l--k-----
30720
fblink
=
-----f--c--l--k-----
61440
Blink frequency
blinking off
2 Hz
1 Hz
0.5 Hz
An additional feature is for an arbitrary selection of LCD segments to be blinked. This
applies to the static and 1:2 multiplex drive modes and can be implemented without any
communication overheads. Using 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-select command (see Table 13).
PCF8576C
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 10 — 22 July 2010
© NXP B.V. 2010. All rights reserved.
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