PCF8545ATTSLASHA datasheet(40/72 Pages) NXP

40 / 72 page

PCF8545

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Product data sheet

Rev. 1 — 13 November 2013

40 of 72

NXP Semiconductors

PCF8545

Universal LCD driver for multiplex rates up to 1:8

9.2.8.1

Status read out

Status read out for I2C-bus operation only. This command initiates the read-out of a fixed

value plus the slave address bit A0 from the PCF8545. The read-out function allows the

I2C master to confirm the existence of the device on the I2C-bus.

If a readout is made, the R/W bit must be logic 1 and then the next data byte following is

provided by the PCF8545 as shown in Figure 31.

In the unlikely case that the chip has entered the internal test mode, detection of this state

is possible by using the modified status read-out detailed in Table 29. The read out value

is modified to indicate that the chip has entered an internal test mode.

Fig 30. I2C-bus protocol write mode

Table 28.

Status read out value

Bit

Symbol

Value

Description

7 to 1

0101010

fixed value

read back value is 01010100

read back value is 01010101

(1) From PCF8545.

Fig 31. I2C-bus protocol read mode

PCF8545ATT/A 数据表(PDF) 40 Page - NXP Semiconductors