PCA9671D datasheet(13/34 Pages) PHILIPS

13 / 34 page

PCA9671_1

Product data sheet

Rev. 01 — 20 December 2006

13 of 34

NXP Semiconductors

PCA9671

Remote 16-bit I/O expander for Fm+ I2C-bus with reset

8.3 Reading from a port (Input mode)

All ports programmed as input should be set to logic 1. To read, the master

(microcontroller) ﬁrst addresses the slave device after it receives the interrupt. By setting

the last bit of the byte containing the slave address to logic 1 the Read mode is entered.

The data bytes that follow on the SDA are the values on the ports.

If the data on the input port changes faster than the master can read, this data may be

lost.

Fig 16. Write mode (output)

A5 A4 A3 A2 A1 A0

SA6

slave address

START condition

R/W

acknowledge

from slave

002aac250

data to port 0

acknowledge

from slave

12345678

SCL

SDA

acknowledge

from slave

write to port

data output from port

tv(Q)

P05

data to port 1

data A0 and B0 valid

P16 output voltage

Itrt(pu)

IOH

P16 pull-up ouput current

P16

tv(Q)

DATA A0 AND B0 VALID

P05 output voltage

Itrt(pu)

IOH

P05 pull-up ouput current

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