PCF8562 Просмотр технического описания (PDF) - Philips Electronics

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PCF8562

Universal LCD driver for low multiplex rates

Philips Electronics 

Philips Semiconductors

Universal LCD driver

for low multiplex rates

Preliminary specification

PCF8562

The PCF8562 includes a RAM bank switching feature in the static and 1 : 2 drive modes. In the static drive mode, the

BANK SELECT command may request the contents of bit 2 to be selected for display instead of the contents of bit 0. In

1 : 2 mode, the contents of bits 2 and 3 may be selected instead of bits 0 and 1. This allows display information to be

prepared in an alternative bank and then selected for display when it is assembled.

6.14 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 can be used to load display data in bit 2 in static drive mode or in bits 2 and 3 in

1 : 2 mode. The input bank selector functions are independent of the output bank selector.

6.15 Blinker

The PCF8562 has a very versatile display blinking capability. The whole display can blink at a frequency selected by the

BLINK command. Each blink frequency is a multiple integer value of the clock frequency; the ratio between the clock

frequency and blink frequency depends on the blink mode selected, as shown in Table 3.

An additional feature allows an arbitrary selection of LCD segments to be blinked 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 command.

In the 1 : 3 and 1 : 4 drive modes, where no alternative RAM bank is available, groups of LCD segments can be blinked

by selectively changing the display RAM data at fixed time intervals.

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.

Table 3 Blinking frequencies

BLINK MODE

Off

2 Hz

1 Hz

0.5 Hz

NORMAL OPERATING MODE

RATIO

−

-f7-C--6--L--8-K-

-1f--C-5---L3---K-6-

-f--C----L---K--

3072

NOMINAL BLINK FREQUENCY

blinking off

2 Hz

1 Hz

0.5 Hz

Note

1. Blink modes 0.5, 1 and 2 Hz, and nominal blink frequencies 0.5, 1 and 2 Hz correspond to an oscillator frequency

(fCLK) of 1536 Hz at pin CLK. The oscillator frequency range is given in Chapter 11.

November 22, 2004

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