The default I2C address is 0x40.

Power Pins

• VIN - this is the power pin. Since the ADC chip uses 2.5-5 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.
  
• Ref+ - this is the positive reference input pin. By default it is not connected and the ADC will use the internal 2.048V reference voltage.
• GND - common ground for power and logic.
• Ref- - this is the negative reference input pin.

I2C Logic Pins

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

ADC Inputs

• A0-A3 - The 4 inputs to the ADC. These inputs can get up to 2k samples per second (you'll need 1MHz I2C speed support for max speed rate), and 24-bits of resolution.

Address Jumpers

On the back of the board are two address jumpers, labeled A0 and A1. These jumpers allow you to chain up to 4 of these boards on the same pair of I2C clock and data pins. To do so, you solder the jumpers "closed" by connecting the two pads:

Other Pins

• DRDY - This is the data ready pin. It is an output pin that is active low.
• !RST - This is the reset pin. To reset the board, pull this pin low.

Power LED and Jumper

• Power LED - In the upper left corner, above the STEMMA connector, on the front of the board, is the power LED, labeled on. It is the green LED.
• LED jumper - In the upper right corner on the back of the board is a jumper for the power LED. If you wish to disable the power LED, cut the trace on this jumper.