The little chip in the middle of the PCB is the actual LIS3DH sensor that does all the motion sensing. We add all the extra components you need to get started, and 'break out' all the other pins you may want to connect to onto the PCB. For more details you can check out the schematics in the Downloads page.
The sensor on the breakout requires 3V power. Since many customers have 5V microcontrollers like Arduino, we tossed a 3.3V regulator on the board. Its ultra-low dropout so you can power it from 3.3V-5V just fine.
- Vin - this is the power pin. Since the 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
- SCL - I2C clock pin, connect to your microcontrollers I2C clock line. Has a 10K pullup already on it.
- SDA - I2C data pin, connect to your microcontrollers I2C data line. Has a 10K pullup already on it.
- To use I2C, keep the CS pin either disconnected or tied to a high (3-5V) logic level.
- SDO - When in I2C mode, this pin can be used for address selection. When connected to GND or left open, the address is 0x18 - it can also be connected to 3.3V to set the address to 0x19
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!
- SCL - this is the SPI Clock pin, its an input to the chip
- SDA - this is the Serial Data In / Master Out Slave In pin, for data sent from your processor to the LIS3DH
- SDO - this is the Serial Data Out / Master In Slave Out pin, for data sent from the LIS3DH to your processor. It's 3.3V logic level out
- CS - this is the Chip Select pin, drop it low to start an SPI transaction. Its an input to the chip
If you want to connect multiple LIS3DH's to one microcontroller, have them share the SDI, SDO and SCK pins. Then assign each one a unique CS pin.