Philips Semiconductors
Product data
Octal SMBus and I
2
C registered interface
PCA9556
SIMPLIFIED SCHEMATIC OF I/O0
DATA FROM
SHIFT REGISTER
CONFIGURATION
REGISTER
DATA FROM
SHIFT REGISTER
WRITE
CONFIGURATION
PULSE
WRITE PULSE
D
FF
C
K
Q
D
FF
I/O0
C
K
Q
ESD PROTECTION DIODE
Q
Q
OUTPUT PORT
REGISTER DATA
OUTPUT
PORT
REGISTER
INPUT PORT
REGISTER
D
FF
READ PULSE
C
K
Q
Q
V
SS
INPUT PORT
REGISTER DATA
DATA FROM
SHIFT REGISTER
WRITE POLARITY
PULSE
D
FF
C
K
Q
POLARITY
REGISTER DATA
Q
POLARITY
INVERSION
REGISTER
SW00795
NOTE:
On power–up or reset, all registers return to default values.
Figure 4. Simplified schematic of I/O0
2002 Mar 28
5