TCA9543A_15 Datasheet, PDF (16/32 Pages) Texas Instruments – TCA9543A Low Voltage 2-Channel I2C Bus Switch With Interrupt Logic And Reset

TCA9543A
SCPS206A – MARCH 2014 – REVISED FEBRUARY 2015
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9.6.4 Interrupt Handling
The TCA9543A provides two interrupt inputs (one for each channel) and one open-drain interrupt output (see
Table 2). When an interrupt is generated by any device, it is detected by the TCA9543A and the interrupt output
is driven low. The channel does not need to be active for detection of the interrupt. A bit also is set in the control
register.
Bit 4 and Bit 5 of the control register correspond to the INT0 and INT1 inputs of the TCA9543A, respectively.
Therefore, if an interrupt is generated by any device connected to channel 1, the state of the interrupt inputs is
loaded into the control register when a read is accomplished. Likewise, an interrupt on any device connected to
channel 0 would cause bit 4 of the control register to be set on the read. The master then can address the
TCA9543A and read the contents of the control register to determine which channel contains the device
generating the interrupt. The master then can reconfigure the TCA9543A to select this channel, and locate the
device generating the interrupt and clear it.
It should be noted that more than one device can provide an interrupt on a channel, so it is up to the master to
ensure that all devices on a channel are interrogated for an interrupt.
The interrupt inputs may be used as general-purpose inputs if the interrupt function is not required.
If unused, interrupt input(s) must be connected to V_CC through a pull-up resistor.
Table 2. Control Register Read (Interrupt)⁽¹⁾
D7
D6
INT1
INT0
D3
0
X
X
X
X
1
0
X
X
X
X
1
0
0
0
0
0
D2
B1
B0
COMMAND
X
X
X
No interrupt on channel 0
Interrupt on channel 0
X
X
X
No interrupt on channel 1
Interrupt on channel 1
0
0
0
No channel selected; power-up/reset default state
(1) Two interrupts can be active at the same time.
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