IC Data Sheets
8
.
8
.4
Diagram
, PCA9555 (IC U29)
Figure
8
-4 Internal block diagram and pin configuration
Block Dia
g
ram
Pin Confi
g
uration
1
8
4
3
0_
3
0
8
_090205.ep
s
090205
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
INT
A1
A2
I/O0.0
I/O0.1
I/O0.2
I/O0.3
I/O0.4
I/O0.5
I/O0.6
I/O0.7
V
DD
SDA
SCL
A0
I/O1.7
I/O1.6
I/O1.5
I/O1.3
I/O1.4
I/O1.2
I/O1.1
I/O1.0
V
SS
PCA9555
POWER-ON
RESET
INPUT
FILTER
I
2
C/SMBUS
CONTROL
INPUT/
OUTPUT
PORTS
WRITE pulse
READ pulse
A0
A1
A2
SCL
SDA
V
DD
V
SS
8-BIT
I/O0.0
I/O0.1
I/O0.2
I/O0.3
I/O0.4
I/O0.5
I/O0.6
I/O0.7
NOTE: ALL I/Os ARE SET TO INPUTS AT RESET
V
INT
INT
8-BIT
INPUT/
OUTPUT
PORTS
I/O1.0
I/O1.1
I/O1.2
I/O1.3
I/O1.4
I/O1.5
I/O1.6
I/O1.7
WRITE pulse
READ pulse
LP FILTER