LSM9DS0 Datasheet, PDF (22/74 Pages) STMicroelectronics – iNEMO inertial module 3D accelerometer, 3D gyroscope, 3D magnetometer

Functionality
4
Functionality
LSM9DS0
The LSM9DS0 is a system-in-package featuring a 3D digital accelerometer, a 3D digital
magnetometer, and a 3D digital gyroscope.
The device includes specific sensing elements and two IC interfaces capable of measuring
both the acceleration/magnetometer and angular rate applied to the module and to provide
a signal to external applications through an SPI/I²C serial interface.
The various sensing elements are manufactured using specialized micromachining
processes, while the IC interfaces are developed using a CMOS technology that allows the
design of a dedicated circuit which is trimmed to better match the sensing element
characteristics.
The LSM9DS0 may also be configured to generate an inertial wake-up and free-fall interrupt
signal according to a programmed acceleration event along the enabled axes.
4.1
4.1.1
4.1.2
Self-test
Accelerometer
The self-test allows the linear acceleration sensor functionality to be tested without moving
it. The self-test function is off when the self-test bit (ST) is programmed to ‘0’. When the self-
test bit is programmed to ‘1’ an actuation force is applied to the sensor, simulating a definite
input acceleration. In this case the sensor outputs exhibit a change in their DC levels which
are related to the selected full scale through the device sensitivity. When the self-test is
activated, the device output level is given by the algebraic sum of the signals produced by
the acceleration acting on the sensor and by the electrostatic test-force. If the output signals
change within the amplitude specified inside Section 2.1: Sensor characteristics, then the
sensor is working properly and the parameters of the interface chip are within the defined
specifications.
Gyroscope
The self-test allows to test the mechanical and electric part of the sensor, allowing the
seismic mass to be moved by means of an electrostatic test-force. When the ST is activated
by the IC, an actuation force is applied to the sensor, emulating a definite Coriolis force. In
this case the sensor output will exhibit an output change.
When the ST is active, the device output is given by the algebraic sum of the signals
produced by the velocity acting on the sensor and by the electrostatic test-force.
For polarity please refer to Table 31: Self-test mode configuration.
4.2
4.2.1
Linear acceleration main digital blocks
FIFO
The LSM9DS0 embeds 32 slots of data FIFO for each of the three output channels: X, Y
and Z. This allows consistent power saving for the system, since the host processor does
not need to continuously poll data from the sensor, but it can wake up only when needed
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