Datasheet

Data Sheet
BMA456
Page 31
BST-BMA456-DS000-01 | Version 1.1 | October 2017 Bosch Sensortec
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BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
4.6. Interrupt Features
Global Configuration
The configuration of the interrupt feature engine is described in the Register FEATURES_IN.
In order to reconfigure the features, the user must perform a burst read of the whole content from the
Register FEATURES_IN, followed by a modification of the content, and finally a burst write of the
modified content to the Register FEATURES_IN. The content of the successive bytes read or written
in burst mode correspond to the single bytes 0x00 to 0x3F described in FEATURES_IN.
Make sure sensor is initialized properly before the feature configuration is performed (see description
in chapter 4.2.)
The output of the interrupt features can be read out of the status registers listed below.
Interrupt feature status registers
Feature
Output status
Step Detector/Counter
INT_STATUS_0.step_counter_out
Activity Recognition
INT_STATUS_0.activity_type_out
Tilt on wrist
INT_STATUS_0.wrist_tilt_out
Double Tap / Tap
INT_STATUS_0.wakeup_out
Any Motion / No Motion
INT_STATUS_0.any_no_motion_out
Error Interrupt
INT_STATUS_0.error_int_out
Additionally, the Step counter numeric value is stored in the registers: STEP_COUNTER_0,
STEP_COUNTER_1, STEP_COUNTER_2 and STEP_COUNTER_3.
The Error Interrupt signals that the sensor stopped after a fatal error. The Device reinitialization must
be done.
The Features (algorithms) have as input data the acceleration samples, which are acquired at 50Hz.
Minimum Bandwidth Settings
If Performance mode is enabled (ACC_CONF.acc_perf_mode is 0b1, so continuous mode is used),
then the features are functioning correctly, regardless to the ODR and the Bandwidth that the Host
would set.
If Performance Mode is disabled (ACC_CONF.acc_perf_mode is 0b0) (device in low power mode),
then the minimum ODR setting must comply with the following restrictions:
1. The ODR must be set to minimum 50 Hz for the most features except Double Tap/Tap
2. The ODR must be set to minimum 200 Hz for the use of Double Tap/ Tap feature
If the minimum requirements are not met, the corresponding flag from the register
INTERNAL_STATUS is set.