PCF8562_4

© NXP B.V. 2009. All rights reserved.

Product data sheet

Rev. 04 — 18 March 2009

18 of 36

NXP Semiconductors

PCF8562

Universal LCD driver for low multiplex rates

7.14 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 (see Section 7.17) can be used to load display data in row 2 in

static drive mode or in rows 2 and 3 in 1:2 mode. The input bank selector functions are

independent of the output bank selector.

7.15 Blinker

The PCF8562 has a very versatile display blinking capability. The whole display can blink

at a frequency selected by the blink-select command (see Table 13). 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 (see Table 6).

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 Section 7.17).

In the 1:3 and 1:4 drive modes, where no alternative RAM bank is available, groups of

LCD segments can blink selectively by changing the display RAM data at fixed time

intervals.

The entire display can blink 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 (see Section 7.17).

[1]

Blink modes 1, 2 and 3 and the nominal blink frequencies 0.5 Hz, 1 Hz and 2 Hz correspond to an oscillator

Table 6.

Blinking frequencies[1]

Blink mode

Normal operating mode ratio

Nominal blink frequency

off

-

blinking off

1

2 Hz

2

1 Hz

3

0.5 Hz

f

clk

768

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f

clk

1536

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f

clk

3072

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