Hara Systems OSTSen-9250 User Manual

OSTSen-9250 v1.0 1 of 9 Hara Systems Inc.

OSTSen-9250 User Guide

Ver 1.0

Hara Systems Inc.

OSTSen-9250 v1.0 2 of 9 Hara Systems Inc.

1. OSTSen-9250 Overview

OSTSen-9250 is a motion tracking module, which is based on InvenSense MPU-

9250. The MPU-9250 is a multi-chip(MCM) consisting of two dies integrated into a
single QFN package. One die houses the 3-Axis gyroscope and the 3-Axis
accelerometer. The other die houses the AK8963 3-Axis magnetometer from Asahi
Kasei Microdevices Corporation. Hence, the MPU-9250 is a 9-axis Motion Tracking
device that combines a 3-Axis gyroscope, 3-Axis accelerometer and a Digital Motion
Processor™(DMP) all in a small 3x3x1mm package available as a pin-compatible
upgrade from the MPU-6515. With its dedicated I2C sensor bus, the MPU-9250
directly provides complete 9-Axis MotionFusion™ output. The MPU-9250 Motion
Tracking device, with its 9-axis integration, on-chip Motion Fusion™, and run-time
calibration firmware, enables manufacturers to eliminate the costly and complex
selection, qualification, MPU-9250 is also designed to interface with multiple non­inertial digital sensors, such as pressure sensors, on its auxiliary I2C port.

MPU-9250 features three 16-bit analog-to-digital converters(ADCs) for digitalizing
the gyroscope outputs, three 16-bit ADCs for digitalizing the magnetometer outputs.
For precision tracking of both fast and slow motions, the parts feature a user­programmable gyroscope full-scale range of ±250, ±500, ±1000, and
±2000°/sec(dps), a user-programmable accelerometer full-scale range of ±2g, ±4g,
±8g and ±16g, and a magnetometer full-scale range of ±4800uT.

Other industry-leading features include programmable digital filters, a precision
clock with 1% drift from -40°C to 85°C, an embedded temperature sensor, and
programmable interrupts. The device features I2C and SPI serial interfaces, a VDD
operating range of 2.4V to 3.6V, and separate digital IO supply, VDDIO from 1.71V to
VDD.

Communication with all register of the device is performed using either I2C at
400kHz or SPI at 1MHz. For application requiring faster communications, the sensor
and interrupt registers may be read using SPI at 20MHz.

By leveraging its patented and volume-proven CMOS-MEMS fabrication platform,
which integrates MEMS wafers with companion CMOS electronics through wafer­level bonding, InvenSense has driven the package size down to a footprint and
thickness of 3x3x1mm, to provide a very small yet high performance low cost
package. The device provides high robustness by supporting 10,000g shock
reliability.

2. Application

· Location based services, points of interest, and dead reckoning

· Handset and portable gaming

· Motion-based game controllers

· 3D remote controls for Internet connected DTVs and set top boxes, 3D mice

· Wearable sensors for health, fitness and sports

3. Features of MPU9250

3.1 Gyroscope Features

The triple-axis MEMS gyroscope in the MPU-9250 includes a wide range of features:

· Digital-output X-, Y-, and Z-Axis angular rate sensors (gyroscopes) with a user-

programmable full-scale range of ±250, ±500, ±1000, and ±2000°/sec and

integrated 16-bit ADCs

· Digitally-programmable low-pass filter

OSTSen-9250 v1.0 3 of 9 Hara Systems Inc.

· Gyroscope operating current: 3.2mA

· Sleep mode current: 8uA

· Factory calibrated sensitivity scale factor

· Self-test

3.2 Accelerometer Features

The triple-axis MEMS accelerometer in MPU-9250 includes a wide range of features:

· Digital-output triple-axis accelerometer with a programmable full scale range of ±2g,

±4g, ±8g and ±16g and integrated 16-bit ADCs

· Accelerometer normal operating current: 450uA

· Low power accelerometer mode current: 8.4uA at 0.98Hz, 19.8uA at 31.25Hz

· Sleep mode current: 8uA

· User-programmable interrupts

· Wake-on-motion interrupt for low power operation of application processor

· Self-test

3.3 Magnetometer Features

The triple-axis MEMS magnetometer in MPU-9250 includes a wide range of features:

· 3-axis silicon monolithic Hall-effect magnetic sensor with a magnetic concentrator

· Wide dynamic measurement range and high resolution with low current

consumption

· Output data resolution is 14 bit (0.6μT/LSB)

· Full scale measurement range is ±4800 μT

· Magnetometer normal operating current: 280uA at 8Hz repetition rate

· Self-test function with internal magnetic source to confirm magnetic sensor

operation on end products

3.4 Additional Features

The MPU-9250 includes the following additional features:

· Auxiliary master I2C bus for reading data from external sensors (e.g., pressure

sensor)

· 3.5mA operating current when all 9 motion sensing axes and the DMP are enabled

· VDD supply voltage range of 2.4 ~ 3.6v

· VDDIO reference voltage for auxiliary I2C devices

· Smallest and thinnest QFN package for portable devices: 3x3x1mm

· Minimal cross-axis sensitivity between the accelerometer, gyroscope and

magnetometer axes

· 512 byte FIFO buffer enables the application processor to read the data in bursts

· Digital-output temperature sensor

· User-programmable digital filters for gyroscope, accelerometer, and temp sensor

· 10,000 g shock tolerant

· 400kHz Fast Mode I2C for communicating with all registers

· 1MHz SPI serial interface for communication with all registers

· 20MHz SPI serial interface for reading sensor and interrupt registers

· MEMS structure hermetically sealed and bonded at wafer level

· RoHS and Green compliant