PCA9673PW datasheet(11/33 Pages) PHILIPS

11 / 33 page

PCA9673_1

Product data sheet

Rev. 01 — 1 February 2007

11 of 33

NXP Semiconductors

PCA9673

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

ﬁrst data byte is acknowledged by the PCA9673, the second data byte P17 to P10 is sent

by the master. Once again, the PCA9673 acknowledges the receipt of the data. Each 8-bit

data is presented on the port lines after it has been acknowledged by the PCA9673.

The number of data bytes that can be sent successively is not limited. After every two

bytes, the previous data is overwritten.

The ﬁrst data byte in every pair refers to Port 0 (P07 to P00), whereas the second data

byte in every pair refers to Port 1 (P17 to P10). See Figure 15.

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 15. Correlation between bits and ports

002aab634

first byte

P06 P05 P04 P03 P02 P01 P00

P07

second byte

P16 P15 P14 P13 P12 P11 P10

P17

Fig 16. Write mode (output)

A5 A4 A3 A2 A1 A0

SA6

slave address

START condition

R/W

acknowledge

from slave

002aab632

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

td(rst)

P16 pull-up output current

INT

P16

tv(Q)

data A0 and B0 valid

P05 output voltage

Itrt(pu)

IOH

P05 pull-up output current

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