- Vin - this is the power pin. Since the sensor 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 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
All pins going into the breakout have level shifting circuitry to make them 3-5V logic level safe. Use whatever logic level is on Vin!
- SCK - This is the SPI Clock pin, its an input to the chip and can use 3 - 5V logic.
- SDO - this is the Serial Data Out / Microcontroller In Sensor Out pin, for data sent from the BMP3xx to your processor. Logic level is 3.3V output, so can be read by 5V microcontrollers.
- SDA - this is the Serial Data In / Microcontroller Out Sensor In pin, for data sent from your processor to the BMP3xx. Its an input to the chip and can use 3 - 5V logic. (SDI on original version)
- CS - this is the Chip Select pin, drop it low to start an SPI transaction. Its an input to the chip and can use 3 - 5V logic.
- INT - this is the Interrupt pin. The BMP3xx can send an output signal to tell you when data is read (we don't use this in our libraries but it is available for your use). The logic level is 3.3V output, so it can be read by 5V microcontrollers.
If you want to connect multiple BMP3xx sensors to one microcontroller, have them share the SDI, SDO and SCK pins. Then assign each one a unique CS pin.
- SCK - this is also the I2C clock pin, connect to your microcontroller's I2C clock line.
- SDA - this is also the I2C data pin, connect to your microcontroller's I2C data line. (SDI on original version)
- STEMMA QT - These connectors allow you to connectors to dev boards with STEMMA QT connectors or to other things with various associated accessories
Leave the CS and SDO pins disconnected for I2C use.