PCF8533 View Datasheet(PDF) - NXP Semiconductors.
Part Name
Description
MFG CO.
'PCF8533' PDF : 45 Pages View PDF
NXP Semiconductors
PCF8533
Universal LCD driver for low multiplex rates
Once the display RAM of the first PCF8533 has been written, the second PCF8533 is
selected by sending the device-select command again. This time however the command
matches the second device's hardware subaddress. Next the load-data-pointer command
is sent to select the preferred display RAM address of the second PCF8533.
This last step is very important because during writing data to the first PCF8533, the data
pointer of the second PCF8533 is incremented. In addition, the hardware subaddress
should not be changed whilst the device is being accessed on the I2C-bus interface.
7.13 Output bank selector
The output bank selector (see Table 13) selects one of the four rows per display RAM
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.
• 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
The SYNC signal resets these sequences to the following starting points: bit 3 for
1:4 multiplex, bit 2 for 1:3 multiplex, bit 1 for 1:2 multiplex, and bit 0 for static mode.
The PCF8533 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.
7.14 Input bank selector
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.
7.15 Blinker
The PCF8533 has a very versatile display blinking capability. The whole display can blink
at a frequency selected by the blink-select command. Each blink frequency is a fraction of
the clock frequency. The ratio between the clock frequency and blink frequency depends
on the blink mode selected, as shown in Table 7.
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.
PCF8533_4
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 04 — 5 March 2010
© NXP B.V. 2010. All rights reserved.
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