The default I2C address is 0x64.

Power Pins

• VIN - this is the power pin. To power the board, give it the same power as the logic level of your microcontroller - e.g. for a 5V microcontroller like Arduino, use 5V. For a 3.3V microcontroller, use 3.3V.
• 3Vo - this is the 3.3V output from the voltage regulator, you can grab up to 100mA from this if you like.
• GND - common ground for power and logic.

I2C Logic Pins

• SCL - I2C clock pin, connect to your microcontroller I2C clock line. This pin is level shifted so you can use 3-5V logic, and there's a 10K pullup on this pin.
• SDA - I2C data pin, connect to your microcontroller I2C data line. This pin is level shifted so you can use 3-5V logic, and there's a 10K pullup on this pin.
• STEMMA QT - These connectors allow you to connect to dev boards with STEMMA QT connectors or to other things with various associated accessories.

Address Pin and Jumper

• ADDR - The address pin for setting the I2C address. You can chain up to two of these boards together on one I2C bus. Leave this pin low for default I2C address 0x64 or tie it high for I2C address 0x65.
• Addr Jumper - On the back of the board is the address jumper, labeled Addr. You can leave this jumper open (low) to keep the board on the default I2C address 0x64. Solder the jumper closed (high) to change the I2C address to 0x65.

Power LED and Jumper

• Power LED - In the upper left corner, above the STEMMA QT connector, on the front of the board, is the power LED, labeled on. It is a green LED.
• LED jumper - This jumper is located on the back of the board and is labeled LED on the board silk. Cut the trace on this jumper to cut power to the "on" LED.