Philips Semiconductors

Product data sheet

PCA9538

with interrupt and reset

2004 Oct 05

7

1

0

0

A1 A0

1

1

1

0

0

A1

A0

1

1

S0

A

A

A

COMMAND BYTE

acknowledge

from slave

R/W

acknowledge

from slave

A

P

NA

acknowledge

from slave

acknowledge

from master

S

DATA

DATA

R/W

first byte

at this moment master-transmitter

becomes master-receiver and

slave-receiver becomes

slave-transmitter

last byte

SW02178

no acknowledge

from master

1

slave address

data from register

data from register

slave address

Figure 8. READ from register

1

1

1

0

0

A1

A0

READ FROM

PORT

DATA INTO

PORT

SDA

S

1A

A

DATA 1

DATA 4

slave address

data from port

data from port

start condition

R/W

acknowledge

from slave

acknowledge

from master

stop

condition

DATA 4

DATA 2

P

DATA 3

SW02179

no acknowledge

from master

NA

INT

12

SCL

34

5

6

7

8

9

NOTES:

1. This figure assumes the command byte has previously been programmed with 00h.

2. Transfer of data can be stopped at any moment by a stop condition.

Figure 9. READ input port register