Datasheet

SDA - this is the I2C data pin for the chip itself, connect to your microcontrollers I2C

data line.

RST - this is the reset pin, for resetting the multiplexer chip. Pulled high by default,

connect to ground to reset

A0 A1 A2 - these are the address selection pins for the multiplexer. By default the

multiplexer is at address 0x70 and these three pins are pulled low. Connect them to

Vin to set the address to 0x71 - 0x77.

A0 is the lowest-significant bit (if it is pulled high, it will increase the address by 1).

A1 is the 2nd-lowest-significant bit (if it is pulled high, it will increase the address by

2).

A2 is the 3rd-lowest-significant bit (if it is pulled high, it will increase the address by 4).

I2C Multiplexed-Side pins:

SDx and SCx: There are 8 sets of SDx and SCx pins, from SD0/SC0 to SD7/SC7.

These are the multiplexed pins. Each one is a completely seperate I2C bus set. So

you have have 8 I2C devices with identical addresses, as long as they are on one I2C

bus each.

These pins do not have any pullups installed, so if you are using a chip or breakout

without i2c pullups be sure to add them! Nicely, you can have Vin be 3.3V and have

these pins pulled up to 5V (that is, they are 5V compliant)

https://learn.adafruit.com/adafruit-tca9548a-1-to-8-i2c-multiplexer-

breakout

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