BMA423 datasheet(44/129 Pages) BOSCH

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Data Sheet

BMA423

Page 44

BST-BMA423-DS000-00 | Version 1.0 | August 2017

Bosch Sensortec

BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.

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/ BMA423 and BMM150

Structure and Concept

The BMA423 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 BMA423 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 BMA423 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 BMA423 autonomously triggers the

Application

Processor

BMA423

BMM150

I2C or SPI primary

interface

I2C auxiliary

interface

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