pca8576d NXP Semiconductors, pca8576d Datasheet - Page 18

• Manufacturer Part Number: pca8576d
• Description: Automotive 40 X 4 Lcd Segment Driver For Low Multiplex Rates Up To 1 4
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCA8576D
Product data sheet
7.13 Output bank selector
7.14 Input bank selector
7.15 Blinking
The storage arrangements described lead to extremely efficient data loading in cascaded
applications. When a series of display bytes are sent to the display RAM, automatic
wrap-over to the next PCA8576D occurs when the last RAM address is exceeded.
Subaddressing across device boundaries is successful even if the change to the next
device in the cascade occurs within a transmitted character (such as during the 14
display data byte transmitted in 1:3 multiplex mode).
The hardware subaddress must not be changed while the device is being accessed on the
I
The output bank selector (see
address for transfer to the display register. The actual row selected depends on the
particular LCD drive mode in operation and on the instant in the multiplex sequence.
The SYNC signal resets these sequences to the following starting points: row 3 for
1:4 multiplex, row 2 for 1:3 multiplex, row 1 for 1:2 multiplex and row 0 for static mode.
The PCA8576D 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 the 1:2 mode, the
contents of rows 2 and 3 may be selected instead of rows 0 and 1. This gives the
provision for preparing display information in an alternative bank and to be able to switch
to it, once it is assembled.
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 row 2 in static drive mode
or in rows 2 and 3 in 1:2 multiplex drive mode by using the bank-select command. The
input bank selector functions independently to the output bank selector.
The PCA8576D has a very versatile display blinking capability. The whole display can
blink at a frequency selected by the blink-select command (see
frequency is a fraction of the clock frequency; the ratio between the clock frequency and
blink frequency depends on the blink mode selected (see
An additional feature allows an arbitrary selection of LCD segments to blink 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-select command (see
2
C-bus interface.
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In 1:4 multiplex mode, all RAM addresses of row 0 are selected, these are followed by
the contents of row 1, 2, and then 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 static mode, row 0 is selected
All information provided in this document is subject to legal disclaimers.
Automotive 40 x 4 LCD segment driver for low multiplex rates
Rev. 1 — 4 April 2011
Table
13) selects one of the four rows per display RAM
Table
Table
14).
Table
6).
PCA8576D
14). Each blink
© NXP B.V. 2011. All rights reserved.
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