The default I2C address is 0x34.

Power Pins

• VIN - this is the power pin. Since the keypad chip uses 3 VDC, we have included a voltage regulator on board that will take 3-5VDC and safely convert it down. 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.
• 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 connectors to dev boards with STEMMA QT connectors or to other things with various associated accessories.

GPIO Pins

• C0-C9 - GPIO or column pins in a keypad matrix. Column number corresponds with pin number
• R0-R7 - GPIO or row pins in a keypad matrix. Row number corresponds with pin number

Other Pins

• INT - Open-drain active-low interrupt output
• RST - Active-low reset input

Power LED

• Power LED - This LED is a green LED located on the front of the board. It is labeled on.