The default I2C address is 0x60.

Power Pins

• VIN - This is the power pin for the ATtiny1616. To power the board, give it the same power as the logic level of your microcontroller - e.g. for a 3V microcontroller like a Feather RP2040 or most Single Board Computers, use 3V, or for a 5V microcontroller like Arduino, use 5V.
• 5Vin - This is the NeoPixel power input, available thru the pin (5V) or terminal block (5Vin) on the left side of the board. To power NeoPixels, you'll need to provide 10-30mA per pixel of clean 5V DC power on this pin.
• 5Vo - This is the NeoPixel power output, available thru the pin (5V) or terminal block (5Vo) on the right side of the board. The power provided on 5Vin is output to this pin for the connected NeoPixels.
• GND/G - This is common ground for power and logic.

I2C Logic Pins

The default I2C address is 0x60.

• SCL - I2C clock pin, connect to your microcontroller I2C clock line. There's a 10K pullup on this pin.
• SDA - I2C data pin, connect to your microcontroller I2C data line. There's a 10K pullup on this pin.
• STEMMA QT - These connectors allow you to connect to development boards with STEMMA QT / Qwiic connectors or to other things with various associated accessories.

Address Jumpers

On the back of the board are three address jumpers, labeled A0, A1, and A2 above the breakout pads along the bottom of the board. These jumpers allow you to chain up to 8 of these boards on the same pair of I2C clock and data pins. To do so, you cut the jumpers "open" by separating the two pads.

If you happen to need more than 8, it's possible to set the I2C address with a special address-change command that is saved to the onboard non-volatile EEPROM memory.

The default I2C address is 0x60. The other address options can be calculated by "adding" the A0/A1/A2 to the base of 0x60.

A0 sets the lowest bit with a value of 1, A1 sets the next bit with a value of 2 and A2 sets the next bit with a value of 4. The final address is 0x60 + A2 + A1 + A0 which would be 0x67.

• 
If only A0 is cut, the address is 0x60 + 1 = 0x61
• 
If only A1 is cut, the address is 0x60 + 2 = 0x62
• 
If only A2 is cut, the address is 0x60 + 4 = 0x64

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

NeoPixel Data Pin

• NEO - The NeoPixel data output pin connects to the data input pin on your NeoPixel strip. This pin is can be accessed along the bottom of the board (NEO), the center of the board below the terminal block (NEO) and via the terminal block (Sig.). It is connected to pin 15 in the seesaw firmware.

UPDI Pin

• UPDI - This is the single-pin Unified Program and Debug Interface. This pin is for external programming or on-chip-debugging for the ATtiny1616 running the seesaw firmware. We have a page in the ATtiny Breakouts with seesaw Learn Guide detailing how to reprogram these chips with your own firmware (at your own risk). We don't provide any support for custom builds of seesaw - we think this is cool and useful for the Maker community.

NeoPixel Activity LED

• NeoPixel Activity LED - On the front of the board, in the center to the right of the ATtiny1616, is the NeoPixel activity LED. It is a red LED. Whenever NeoPixel data is written out to the strip, it will light up. This is useful for debugging your setup

Power LED

• Power LED - On the front of the board, above the STEMMA connector on the left, is the power LED, labeled on. It is the green LED.