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.
• 3V - This is the 3.3V output from the voltage regulator, you can grab up to 100mA from this if you like.
• GND - This is the common ground for power and logic.

I2C Logic Pins

The I2C address is 0x29.

• 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 connectors to dev boards with STEMMA QT connectors or to other things with various associated accessories.

On LED and LED Jumper

• on LED - On the front of the breakout, right above the STEMMA QT connector on the left, is the on LED. It is labeled on on the silk. This green LED lights up when the board is powered.

• LED jumper - On the back of the board is a jumper labeled LED. To disable the on LED, cut the trace between the two pads. To enable it again, bridge the two pads together with solder.

LTR-303 Interrupt Pin

• INT - This is the interrupt pin, available only on the LTR-303. The alert and IRQ capabilities enable you to have a pin trigger when the reading goes above or below threshold values.