pca9539 datasheet

DB, DBQ, DGV, DW, OR PW PACKAGE
(TOP VIEW)
INT
A1
RESET
P00
P01
P02
P03
P04
P05
P06
P07
GND
V
CC
SDA
SCL
A0
P17
P16
P15
P14
P13
P12
P11
P10
24
23
22
21
20
19
18
17
16
15
14
13
1
2
3
4
5
6
7
8
9
10
11
12
24 23 22 21 20
7 8 9 10 11
1
2
3
4
5
6
18
17
16
15
14
13
RGE PACKAGE
(TOP VIEW)
A1 INT
P10
P11 SDA
P06 P07
GND
V
CC
19
SCL
12
P12
P00
P01
P02
P03
P04
P05
A0
P17
P16
P15
P14
P13
RESET
PCA9539
www.ti.com SCPS130G –AUGUST 2005–REVISED JUNE 2014
4 Description (Continued)
The system master can reset the PCA9539 in the event of a time-out or other improper operation by asserting a
low in the RESET input. The power-on reset puts the registers in their default state and initializes the I
2
C/SMBus
state machine. Asserting RESET causes the same reset/initialization to occur without de-powering the part.
The PCA9539 open-drain interrupt (INT) output is activated when any input state differs from its corresponding
Input Port register state and is used to indicate to the system master that an input state has changed.
INT can be connected to the interrupt input of a microcontroller. By sending an interrupt signal on this line, the
remote I/O can inform the microcontroller if there is incoming data on its ports without having to communicate via
the I
2
C bus. Thus, the PCA9539 can remain a simple slave device.
The device outputs (latched) have high-current drive capability for directly driving LEDs. The device has low
current consumption.
The PCA9539 is identical to the PCA9555, except for the removal of the internal I/O pullup resistor, which greatly
reduces power consumption when the I/Os are held low, replacement of A2 with RESET, and a different address
range.
Two hardware pins (A0 and A1) are used to program and vary the fixed I
2
C address and allow up to four devices
to share the same I
2
C bus or SMBus.
5 Pin Configuration and Functions
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