This sensor has 4 mounting holes and 2 header breakout strips.

Power Pins:

• Vin - this is the power pin. Since the sensor uses 3.3V, we have included an onboard voltage regulator 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 micro 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

Logic pins:

• SCL - this is the I2C clock pin, connect to your microcontrollers I2C clock line. There is a 10K pullup on this pin and it is level shifted so you can use 3 - 5VDC. If UART mode is selected, this pin acts as RX.
• SDA - this is the I2C data pin, connect to your microcontrollers I2C data line. There is a 10K pullup on this pin and it is level shifted so you can use 3 - 5VDC. If UART mode is selected, this pin acts as TX.
• RST - this is the reset pin. When it is pulled to ground the sensor resets itself. This pin is level shifted so you can use 3-5VDC logic.

Solder closed the UART SELECT jumper to switch the sensor into UART mode.

UART Logic pins:

• TX - this is the UART transmit pin, connect to your microcontrollers UART RX line. There is a 10K pullup on this pin and it is level shifted so you can use 3 - 5VDC. If I2C mode is selected, this pin acts as SCL.
• RX - this is the UART receive pin, connect to your microcontrollers UART TX line. There is a 10K pullup on this pin and it is level shifted so you can use 3 - 5VDC. If I2C mode is selected, this pin acts as SDA.