TCA9548A I2C 8 CHANNEL MULTIPLEXER MODULE

You just found the perfect I2C sensor, and you want to wire up two, three, or more of them to your Arduino. When you realize “Oh no, this chip has a fixed I2C address, and from what I know about I2C; you cannot have two devices with the same address on the same SDA/SCL pins”. Are you out of luck? You would be if you don’t have this cool CJMCU TCA9548A I2C 8 Channel Multiple extensions development board.

The CJMCU TCA9548A I2C 8 Channel Multiple extensions development board is interesting in that it has an I2C address (0x70 by default) – and you basically send it a command to tell it which I2C multiplexed output you want to talk to, then you can address the board you want to address.

• • 5-V Tolerant Inputs.
  • Supports Hot Insertion.
  • Low Standby Current.
  • Power Up With All Switch Channels Deselected.
  • Active-Low Reset Input.
  • I2C Bus and SMBus Compatible.
  • 1-to-8 Bidirectional Translating Switches.
  • Latch-Up Performance Exceeds 100 mA Per JESD 78, Class II.

Connections:

• • Vin – this is the power pin. Since the sensor chip uses 3-5 VDC. To power, the board, give it the same power as the logic level of your microcontroller – e.g. for a 5V micro like Arduino, use 5V.
  • GND – common ground for power and logic.
  • SCL – this is the I2C clock pin for the chip itself, connect to your microcontrollers I2C clock line.
  • 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).

Package Includes:

• • 1 x CJMCU TCA9548A I2C 8 Channel Multiple extensions development board.