PCF8545ATTSLASHA datasheet(36/72 Pages) NXP

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PCF8545

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Product data sheet

Rev. 1 — 13 November 2013

36 of 72

NXP Semiconductors

PCF8545

Universal LCD driver for multiplex rates up to 1:8

Bus interfaces

9.1 Control byte and register selection

After initiating the communication over the bus and sending the slave address (I2C-bus,

see Section 9.2) or subaddress (SPI-bus, see Section 9.3), a control byte follows. The

purpose of this byte is to indicate both, the content for the following data bytes (RAM, or

command) and to indicate that more control bytes will follow.

Typical sequences could be:

• Slave address/subaddress - control byte - command byte - command byte - command

byte - end

• Slave address/subaddress - control byte - RAM byte - RAM byte - RAM byte - end

• Slave address/subaddress - control byte - command byte - control byte - RAM byte -

end

In this way, it is possible to send a mixture of RAM and command data in one access or

alternatively, to send just one type of data in one access.

Table 25.

Control byte description

Bit

Symbol

Value

Description

7CO

continue bit

last control byte

control bytes continue

6 to 5

RS[1:0]

command register

RAM data

10, 11

unused

4 to 0

unused

Fig 25. Control byte format

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