The default I2C address is 0x60.

Power Pins

  • VIN - this is the power pin. Since the clock generator chip may use 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.

Clock Out Pins

  • 0, 1, and 2 - These are the 3 independent clock generated outputs. They are square waves, from 0-3V.

Clock output 1 is also brought out to an SMA edge-launch connector on the other side of the PCB. You can purchase and solder on an edge-launch SMA connector if you want to pipe the signal into an RF cable.

Power LED and LED Jumper

  • Power LED - In the upper left corner, above the STEMMA connector, on the front of the board, is the power LED, labeled on. It is the green LED.
  • LED jumper - This jumper is located on the back of the board. Cut the trace on this jumper to cut power to the "on" LED.

This guide was first published on Aug 12, 2014. It was last updated on Jun 10, 2024.

This page (STEMMA QT Pinouts) was last updated on Mar 08, 2024.

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