The default I2C address is 0x74.

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.
• 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.

Other Pins

• SYNC - The SYNC pin is an input that can trigger synchronous readings from the AS7331 with an external pulse.
• RDY - The data ready pin can be configured as push-pull or open drain in software to alert you when a sensor conversion is complete.

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 jumper "closed" by connecting the two pads.

The default I2C address is 0x74. The other address option can be calculated by “adding” A0 and/or A1 to the base of 0x74.


For example, if A1 is soldered closed and A0 is soldered closed, the address is 0x74 + 2 + 1 = 0x77.


If only A0 is soldered closed, the address is 0x74 + 1 = 0x75


If only A1 is soldered closed, the address is 0x74 + 2 = 0x76

The table below shows all possible addresses, and whether the jumper(s) should be high (closed) or low (open).

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.