TCA9543A_15 Datasheet, PDF (11/32 Pages) Texas Instruments – TCA9543A Low Voltage 2-Channel I2C Bus Switch With Interrupt Logic And Reset

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9 Detailed Description
TCA9543A
SCPS206A – MARCH 2014 – REVISED FEBRUARY 2015
9.1 Overview
The TCA9543A is a 2-channel, bidirectional translating I²C switch. The master SCL/SDA signal pair is directed to
two channels of slave devices, SC0/SD0-SC1/SD1. Either individual downstream channel can be selected as
well as both channels. The TCA9543A also supports interrupt signals in order for the master to detect an
interrupt on the INT output terminal that can result from any of the slave devices connected to the INT1-INT0
input terminals.
The device offers an active-low RESET input which resets the state machine and allows the TCA9543A to
recover should one of the downstream I²C buses get stuck in a low state. The state machine of the device can
also be reset by cycling the power supply, V_CC, also known as a power-on reset (POR). Either using the RESET
function or causing a POR will cause both channels to be deselected.
The connections of the I²C data path are controlled by the same I²C master device that is switched to
communicate with multiple I²C slaves. After the successful acknowledgment of the slave address (hardware
selectable by A0 and A1 terminals), a single 8-bit control register is written to or read from to determine the
selected channels and state of the interrupts.
The TCA9543A may also be used for voltage translation, allowing the use of different bus voltages on each
SCn/SDn pair such that 1.8-V, 2.5-V, or 3.3-V parts can communicate with 5-V parts. This is achieved by using
external pull-up resistors to pull the bus up to the desired voltage for the master and each slave channel.
9.2 Functional Block Diagram
6
SC0
TCA9543A
10
SC1
5
SD0
9
SD1
7
GND
14
VCC
3
RESET
Switch Control Logic
Power-On
Reset
12
SCL
13
SDA
INT0 ⁴
INT1 ⁸
Input Filter
I²C Bus
Control
1 _A0
2 _A1
Interrupt Logic
Output Filter
11
INT
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