TCA9555_16 Datasheet, PDF (15/46 Pages) Texas Instruments – Low-Voltage 16-Bit I2C and SMBus I/O Expander with Interrupt Output and Configuration Registers

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9 Detailed Description
TCA9555
SCPS200D – JULY 2009 – REVISED JULY 2016
9.1 Overview
The TCA9555 is a 16-bit I/O expander for the two-line bidirectional bus (I²C) is designed for 1.65-V to 5.5-V V_CC
operation. It provides general-purpose remote I/O expansion for most microcontroller families via the I²C
interface.
One of the features of the TCA9555, is that the INT output 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 I²C bus. Thus, the TCA9555 can remain a
simple slave device.
9.2 Functional Block Diagram
TCA9555
1
INT
21
A0
2
A1
3
A2
22
SCL
23
SDA
Input
Filter
LP Filter
I²C Bus
Control
Interrupt
Logic
Shift
Register
16 Bits
I/O
Port
P07-P00
P17-P10
24
V_CC
GND
12
Power-On
Reset
Write Pulse
Read Pulse
Pin numbers shown are for the PW package.
All I/Os are set to inputs at reset.
Figure 22. Logic Diagram (Positive Logic)
9.3 Feature Description
9.3.1 5-V Tolerant I/O Ports
The TCA9555 features I/O ports which are tolerant of up to 5 V. This allows the TCA9555 to be connected to a
large array of devices. To minimize ICC, any inputs must be sure that the input voltage stays within V_IH and V_IL of
the device as described in the Electrical Characteristics table.
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