BST-BMI160-DS000-06 | Revision 0.7 | December 2014 Bosch Sensortec
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Note: Specifications within this document are preliminary and subject to change without notice.
that for a certain filter configuration, the ODR has to be 4 times higher than in the normal filter
mode. Conversely, for a certain filter configuration, the filter bandwidth will be 4 times smaller
than the bandwidth achieved for the same ODR in the normal filter mode. For example, for
ODR=50Hz we will have a 3dB cutoff frequency of 5.06Hz.
2.4.1.2 Accelerometer data processing for low power mode
When low power mode is used, the undersampling mode must be enabled (acc_us=0b1). In this
configuration mode, the accelerometer regularly changes between a suspend power mode
phase where no measurement is performed and a normal power mode phase, where data is
acquired. The period of the duty cycle for changing between suspend and normal mode will be
determined by the output data rate (acc_odr). The output data rate can be configured in one of
12 different valid ODR configurations going from 0.78Hz up to 1600Hz.
The samples acquired during the normal mode phase will be averaged and the result will be the
output data. The number of averaged samples can be determined by the parameter acc_bwp
through the following formula:
averaged samples = 2
(Val(acc_bwp))
skipped samples = (1600/ODR)-averaged samples
A higher number of averaged samples will result in a lower noise level of the signal, but since
the normal power mode phase is increased, the power consumption will also rise. This
relationship can be observed in chapter Power Consumption.
Note: When undersampling (acc_us=0b1 in Register (0x40) ACC_CONF) and the use of pre-
filtered data for interrupts or FIFO is configured an error code is flagged in Register (0x02)
ERR_REG. Pre-filtered data for interrupts are configured through int_motion_src=0b1 or
int_tap_src=0b1 in Register (0x58-0x59) INT_DATA. Pre-filtered data for the FIFO are
configured through acc_fifo_filt_data=0b0 in Register (0x45) FIFO_DOWNS.
2.4.2 Data Processing Gyroscope
The gyroscope digital filter can be configured through the parameters: gyr_bwp and gyr_odr in
GYR_CONF for the gyroscope. There is no undersampling option for the gyroscope data
processing. The gyroscope data can only be processed in normal power mode.
There are three data processing modes defined by gyr_bwp. Normal mode, OSR2, OSR4. For
details see chapter 2.11.13.
2.4.2.1 Gyroscope data processing for normal power mode
When the filter mode is set to normal (gyr_bwp=0b010), the gyroscope data is sampled at
equidistant points in the time, defined by the gyroscope output data rate parameter (gyr_odr).
The output data rate can be configured in one of eight different valid ODR configurations going
from 25Hz up to 3200Hz.
Note: Lower ODR values than 25Hz are not allowed. If they are used they result in an error
code in Register (0x02) ERR_REG.
The filter bandwidth as configured by gyr-odr shows a 3db cutoff frequency shown in the
following table:
3dB Cutoff frequency [Hz]