Inertial Measurement Unit (IMU) module - 10-axis module incorporating: Gyroscope, Accelerometer, Magnetometer(aka Compass), and Barometric sensor (Temperature/Altimeter); - Based on the InvenSense 9-axis chip MPU-9250 (Gyro, Acc., Mag.), and the MEAS MS5611-01BA03 Pressure sensor; - 4-wire, SPI interface topology, with individual Chip Select (Slave Select) for each chip; - If you want to use I2C interface, 2-wire, please refer to the datasheet for design adjustments; More information about SPI and I2C interfaces: - http://www.byteparadigm.com/applications/introduction-to-i2c-and-spi-protocols/ - https://learn.sparkfun.com/tutorials/serial-peripheral-interface-spi/all - https://learn.sparkfun.com/tutorials/i2c PCB considerations: - 2 layers board; - 8 mils trace width for power; - 6 mils for all other traces; - 6 mils minimum clearance for copper to copper; - Via with 13 mils hole and 7 mils annular ring; - All vias below components have solder mask to prevent short circuit when reflowing/soldering SMD components; - MPU-9250 and MS5611-01BA03 footprint based on the available reference design and documentation from each company respectively; - The NC pins of the MPU-9250 are NOT internally connected, so can be used for PCB trace routing; - The CSBn pins of the MS5611-01BA03 are connected internally; MODULE Pins description: - 1 - VDD - Power supply - (range 2.4V to 3.6V) - 2 - GND (0V). SPI Interface: 3 - SDO(MISO) - Master Input Slave Output; 4 - SCLK - Clock input reference for the SPI communication; 5 - SDI(MOSI) - Master Output Slave Input; 6 - CSn(SS) - Chip Select (Slave Select) - Digital input to enable the MPU-9250 to transmit and receive through the SPI bus; 7 - CSBn(SS) - Chip Select (Slave Select) - Digital input to enable the MS5611-01BA03 to transmit and receive through the SPI bus; MISC. 8 - INT - MPU-9250 pin, Interrupt digital output (totem pole or open-drain); Technical documents/information about the chips: - Invensense MPU9250: http://www.invensense.com/mems/gyro/mpu9250.html - MEMS MS5611-01BA03 Pressure Sensor: http://www.meas-spec.com/product/pressure/MS5611-01BA03.aspx