Philips Semiconductors

Product data sheet

PCA9538

with interrupt and reset

2004 Oct 05

6

Device address

1

1

1

0

0

A1

A0

SLAVE ADDRESS

FIXED

HARDWARE SELECTABLE

R/W

SW02175

Figure 5. PCA9538 address

Bus transactions

Data is transmitted to the PCA9538 registers using the write mode as shown in Figures 6 and 7. Data is read from the PCA9538 registers using

the read mode as shown in Figures 8 and 9. These devices do not implement an auto-increment function so once a command byte has been

sent, the register which was addressed will continue to be accessed by reads until a new command byte has been sent.

12

SCL

WRITE TO

PORT

DATA OUT

FROM PORT

3

4

567

8

SDA

S0

A

A

A

11

1

0

0A1

A0

DATA 1

slave address

data to port

start condition

R/W

acknowledge

from slave

acknowledge

from slave

acknowledge

from slave

DATA 1 VALID

SW02176

9

1

00

0

0

00

0

command byte

P

Figure 6. WRITE to output port register

12

SCL

3

4

567

8

SDA

S0

A

A

A

11

1

0

0A1

A0

DATA

slave address

data to register

start condition

R/W

acknowledge

from slave

acknowledge

from slave

acknowledge

from slave

SW02177

9

00

0

0

00

1

command byte

1/0

DATA TO

REGISTER

P

Figure 7. WRITE to configuration or polarity inversion registers