Datasheet

Data Sheet
BMA456
Page 44
BST-BMA456-DS000-01 | Version 1.1 | October 2017 Bosch Sensortec
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Note: Specifications within this document are subject to change without notice.
4.8. Auxiliary Sensor Interface
The auxiliary interface allows to attach one auxiliary sensor (e.g. magnetometer) on dedicated auxiliary
sensor interface as shown in Figure…
6-DOF Solution w/ BMA456 and BMM150
Structure and Concept
The BMA456 controls the data acquisition of the auxiliary sensor and presents the data to the
application processor through the primary I2C or SPI interface. No other I2C master or slave devices
must be attached to the auxiliary sensor interface.
The BMA456 autonomously reads the sensor data from a compatible auxiliary sensor without
intervention of the application processor and stores the data in its data registers and FIFO. The initial
setup of the auxiliary sensor after power-on is done through indirect addressing.
The main benefits of the auxiliary sensor interface are
 Synchronization of sensor data of auxiliary sensor and accelerometer. This results in an
improved sensor data fusion quality.
 Usage of the BMA456 FIFO for auxiliary sensor data (BMM150 does not have a FIFO). This is
important for monitoring applications.
Interface Configuration
The configuration registers that control the auxiliary sensor interface operation, are only affecting the
interface to the auxiliary sensor, not the configuration of the sensor itself (this must be done in setup
mode).
There are three basis configurations of the auxiliary sensor interface:
 No auxiliary sensor access
 Setup mode: Auxiliary sensor access in manual mode
 Data mode: Auxiliary sensor access through hardware readout loop.
The setup of the auxiliary sensor itself must be done through the primary interface using indirect
addressing in setup mode. When collecting sensor data, the BMA456 autonomously triggers the
Application
Processor
BMA456
BMM150
I2C or SPI primary
interface
I2C auxiliary
interface