The default I2C address is 0x49.
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 3V microcontroller like a Feather RP2040, use 3V, or for a 5V microcontroller like Arduino, use 5V.
- GND - This is common ground for power and logic.
I2C Logic Pins
The default I2C address is 0x49.
- 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 four address jumpers, labeled A0, A1, A2 and A3, above the breakout pads along the bottom of the board. These jumpers allow you to chain up to 16 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 16, 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 0x49. The other address options can be calculated by "adding" the A0/A1/A2/A3 to the base of 0x49.
A0 sets the lowest bit with a value of 1, A1 sets the next bit with a value of 2, A2 sets the next bit with a value of 4 and A3 sets the next bit with a value of 8. The final address is 0x49 + A3 + A2 + A1 + A0 which would be 0x58.
If only A0 is cut, the address is 0x49 + 1 = 0x4A
If only A1 is cut, the address is 0x49 + 2 = 0x4B
If only A2 is cut, the address is 0x49 + 4 = 0x4D
If only A3 is cut, the address is 0x49 + 8 = 0x51
The table below shows all possible addresses, and whether the pin(s) should be high (closed) or low (open).
Interrupt Pin and LED
- INT - This is the interrupt output pin. It can be configured to pulse low whenever rotation or push-buttoning is detected so you do not have to spam-read the I2C port to detect motion.
- Interrupt LED - On the back of the board below the STEMMA QT port on the left is the interrupt LED. It is the red LED and turns on whenever an interrupt is detected.
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 ATtiny816 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.
Power LED
- Power LED - On the back of the board, above the STEMMA connector on the right, is the power LED, labeled on. It is the green LED.
ANO Encoder Pins
On the front of the board is the outline of the ANO encoder on the board silk. This lets you know how you should place the ANO encoder on the board for soldering. The pins on the encoder are keyed so it only fits onto the breakout one way. Please note that the encoder is NOT included! You'll need to pick one up from the shop and solder it to the board.
- ENCA - This is the rotary encoder A pin (yellow square)
- ENCB - This is the rotary encoder B pin (purple square)
- SW1 - This pin is the select button, pin 1 in the seesaw firmware (aqua square)
- SW2 - This pin is the up button, pin 2 in the seesaw firmware (red square)
- SW3 - This pin is the left button, pin 3 in the seesaw firmware (blue square)
- SW4 - This pin is the down button, pin 4 in the seesaw firmware (white square)
- SW5 - This pin is the right button, pin 5 in the seesaw firmware (green square)
- COMA - Common pin A (pink square)
- COMB - Common pin B (orange square).
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