I2C connections are awesome to use with for Arduino or similar microcontroller boards. Controlling a bunch of devices by using only two pins is really great, but there is a small problem. Some I2C boards have fixed I2C addresses. Sadly you cannot use more than one I2C device together if they have the same I2C address.
So what happens if you find a great sensor operated over I2C and you want to use more than one of that sensor. The best solution is TCA9548A I2C Multiplexer which lets you use up to 8 devices over I2C which have the same address.
Using TCA9548A I2C Multiplexer is pretty simple. The multiplexer itself is operated on I2C line with the default address 0x70 (the address is selectable between 0x70 and 0x77). After wiring the SDA and SCL pins of your microcontroller to the multiplexer, you just write a byte, selecting the multiplexed output line and the rest of the I2C packets are set to send to that line. In theory you can use 8 of these multiplexers on the same address and use 64 devices having the same I2C address.
The TCA9548A chip onboard is 3,3V and 5V compliant, so it can be used with both logical levels.
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Adafruit Product Page: https://www.adafruit.com/products/2717