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TCA9555_16 Datasheet, PDF (25/46 Pages) Texas Instruments – Low-Voltage 16-Bit I2C and SMBus I/O Expander with Interrupt Output and Configuration Registers
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10 Application and Implementation
TCA9555
SCPS200D – JULY 2009 – REVISED JULY 2016
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
10.1 Application Information
Applications of the TCA9555 has this device connected as a slave to an I2C master (processor), and the I2C bus
may contain any number of other slave devices. The TCA9555 is typically be in a remote location from the
master, placed close to the GPIOs to which the master needs to monitor or control.
IO Expanders such as the TCA9555 are typically used for controlling LEDs (for feedback or status lights),
controlling enable or reset signals of other devices, and even reading the outputs of other devices or buttons.
10.2 Typical Application
Figure 34 shows an application in which the TCA9555 can be used to control multiple subsystems, and even
read inputs from buttons.
VCC
(5 V)
VCC
10 kΩ 10 kΩ
SCL
Master
Controller SDA
INT
GND
10 kΩ 10 kΩ
24 Ω 2 kΩ
VCC
22
SCL
23
SDA
1
INT
P00 4
5
P01
P02 6
7
P03
8
P04
9
P05
TCA9555
3 A2
2 A1
21 A0
P06 10
P07 11
P10 13
P11 14
P12 15
P13 16
P14 17
P15 18
P16 19
GND P17 20
12
Keypad
Subsystem 1
(e.g., Temperature
Sensor)
INT
Subsystem 2
(e.g., Counter)
RESET
A
ENABLE
B
VCC
Controlled Switch
(e.g., CBT Device)
ALARM
Subsystem 3
(e.g., Alarm)
A. Device address is configured as 0100100 for this example.
B. P00, P02, and P03 are configured as outputs.
C. P01, P04–P07, and P10–P17 are configured as inputs.
D. Pin numbers shown are for the PW package.
Figure 34. Typical Application
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