TCA9539_15 Datasheet, PDF (25/42 Pages) Texas Instruments – Low Voltage 16-Bit I2C and SMBus Low-Power I/O Expander

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9 Application and Implementation
TCA9539
SCPS202B – OCTOBER 2009 – REVISED OCTOBER 2015
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.
9.1 Application Information
Applications of the TCA9539 will have this device connected as a slave to an I²C master (processor), and the I²C
bus may contain any number of other slave devices. The TCA9539 will 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 TCA9539 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.
9.2 Typical Application
Figure 34 shows an application in which the TCA9539 can be used.
V_CC
(5 V)
V_CC
10 kΩ
SCL
Master
Controller SDA
INT
GND
10 kΩ
10 kΩ
10 kΩ
24 Ω 2 kΩ
V_CC
22
SCL
23
SDA
1
3 ^INT
RESET
P00 ⁴
P01 ⁵
P02 ⁶
P03 ⁷
P04 ⁸
P05 ⁹
100 kΩ
100 kΩ 100 kΩ
Subsystem 1
(e.g., Temperature
Sensor)
INT
Subsystem 2
(e.g., Counter)
RESET
A
ENABLE
B
TCA9539
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
V_CC
Controlled Switch
(e.g., CBT Device)
ALARM
Subsystem 3
(e.g., Alarm)
A. Device address is configured as 1110100 for this example.
B. P00, P02, and P03 are configured as outputs.
C. P01 and P04 to P17 are configured as inputs.
D. Pin numbers shown are for the PW package.
Figure 34. Application Schematic
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