User's Manual

UMXXX
mentioned above); the double tap event is detected when a first tap is detected,
and a second tap is detected after the programmed “quiet” time window but before
the maximum “duration” time window; for a reliable detection of short duration shock
events, it is suggested to configure the device to use a high sampling rate (e.g.
400Hz). If more than one axis is enabled, and they are over their respective
threshold, the highest priority axis is used; the priority can be configured.
• Activity/Inactivity event: uses the same data as selected for the wake-up event; if
inactivity is detected (data below the programmed threshold for the programmed
duration), the device automatically goes to low-power mode and reduces the
accelerometer sampling rate down to 12.5Hz to minimize power consumption; if
activity is detected (wake-up event) the device automatically returns to the
programmed accelerometer operating mode and sampling rate. This feature may
be configured to put the gyroscope in power-down or sleep mode when the
accelerometer is in low-power mode.
• Stationary/Motion event: is a particular case of Activity/Inactivity event; event
detection is the same but the device does not change in power mode or sampling
rate.
Single/double tap recognition may be used to enable user interaction in addition to the use
of the button present in the BlueNRG-2 sensor node. The on-board LED can be used to
give feedback to the user.
LSM6DSO INTERRUPT GENERATION AND ADVANCED FUNCTIONS
Specific digital processing blocks enable advanced functions and algorithms: pedometer
functions with step detector and step counter, tilt detection, significant motion detection.
These functions require the output data rate to be 26 Hz or higher.
• Pedometer functions: step detector and step counter. An interrupt is generated
whenever a step is detected and the corresponding counter is incremented by 1
(max value is 65535). Optionally the interrupt can be generated only if at least one
step is detected in a configurable time interval. In order to avoid false detections, N
consecutive steps must be detected before the first interrupt is generated (de-
bounce functionality), when this happens the counter is incremented by N. the
parameter N is configurable. Two additional blocks can be enabled to enhance the
rejection of false-positives: the first block enable the step detection only is statistical
data matches the walking pattern; the second block adapts the embedded
algorithm to slow pace walking patterns. STMicroelectronics provides the software
tools to generate specific pedometer configurations based on data logs. The step
counter is not reset to 0 when the accelerometer is configured to power-down