Philips Semiconductors

Product data sheet

PCA9552

2004 Oct 01

9

Bus transactions

A1

A0

12

SCL

WRITE TO

REGISTER

DATA OUT

FROM PORT

3

4

567

8

SDA

S0

A

A

A

11

0

0

A2

DATA 1

slave address

data to register

start condition

R/W

acknowledge

from slave

acknowledge

from slave

acknowledge

from slave

DATA 1 VALID

SW02000

9

B0

00

0

AI

B3

B2

B1

command byte

Figure 10. WRITE to register

0

0

A2

A1

A0

1

1

0

0

A0

1

1

S0

A

A

A

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

SW01099

no acknowledge

from master

1

slave address

data from register

data from register

slave address

auto-increment

register address

if AI = 1

A1

A2

AI B3

B0

0

0

B1

B2

0

Figure 11. READ from register

11

0

0

A2

A1

A0

READ FROM

PORT

DATA INTO

PORT

SDA

S1

A

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

SW01096

no acknowledge

from master

NA

DATA 1

NOTE:

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

Figure 12. READ input port register