Philips Semiconductors
Product data
PCA9556
Octal SMBus and I2C registered interface
2002 Mar 28
7
SMBus Address
00
1
A2
A1
A0
slave address
su01048
fixed
programmable
R/W
Figure 6. PCA9556 address
SMBus Transactions
Data is transmitted to the PCA9556 registers using Write Byte transfers (see Figures 7 and 8). Data is read from the PCA9556 registers using
Read and Receive Byte transfers (see FIgures 9 and 10).
12
SCL
WRITE TO
PORT
DATA OUT
FROM PORT
3
4
567
8
SDA
S0
A
0
1
A2
A1
A0
DATA 1
slave address
data to port
start condition
R/W
acknowledge
from slave
acknowledge
from slave
acknowledge
from slave
tpv
DATA 1 VALID
SW00797
9
1
00
0
00
0
command byte
P
Figure 7. WRITE to output port register via Write Byte Protocol
12
SCL
3
4
567
8
SDA
S0
A
0
1
A2
A1
A0
DATA
slave address
data to register
start condition
R/W
acknowledge
from slave
acknowledge
from slave
acknowledge
from slave
SW00798
9
00
0
00
1
command byte
1/0
P
Figure 8. WRITE to I/O configuration or polarity inversion registers via Write Byte Protocol