LSM6DSL - iNEMO inertial module: always-on 3D accelerometer and 3D gyroscope Milano, October 19 th -20 th 2016
LSM6DSL - iNEMO inertial module:
always-on 3D accelerometer and
3D gyroscope
Milano, October 19th-20th 2016
Summary• XL/Gyro filtering chain
• Embedded digital features:
• Free-fall
• Wake-up
• 6D/4D orientation detection
• Single-tap and double-tap sensing
• Activity/Inactivity recognition
• Embedded Android functions:
• Pedometer functions (step counter and step detector)
• Significant Motion detection
• Relative Tilt
• Mode 2: Sensor Hub mode
• FIFO
2
XL Filtering Chain
SLOPE
FILTER
HPCF_XL[1:0]
00
01
10
11
SPI/
I2C
1
0
HP_SLOPE_XL_EN
LPF2_XL_EN
0
1
INPUT_COMPOSITE
0
1
LPF1_BW_SEL
0
1
Digital
HP Filter
HPCF_XL[1:0]
Digital
LP Filter
LPF2
HPCF_XL[1:0]
S/D Tap
6D / 4D0
1
LOW_PASS_ON_6D
1
0
SLOPE_FDS
Wake-up
Activity /
Inactivity
Free-fall
Smart
functions
FIFO
ADC
Digital
LP Filter
Analog
Anti-aliasing
LP Filter
ODR_XL[3:0]
LPF1ODR/2*
ODR/4**
3
* The cut-off value of this LPF1 output is
ODR/2 when the XL is in HP mode. It’s
equal to 740Hz in LP/NM mode
** The cut-off value of this LPF1 output is
always ODR/4 (in both HP mode and
LP/NM mode)
Slope Filter 4
ACCELERATION
SLOPE
Slope(tn) = [ acc(tn) - acc(tn-1) ] / 2
acc(tn)
acc(tn-1)
5
ADCDigital
HP Filter
HP_EN_G
Analog
Anti-aliasing
LP Filter
0
1
LPF1_SEL_G
Digital
LP Filter
FTYPE[1:0]
LPF1
0
1
SPI/I2C
FIFODigital
LP Filter
ODR_G[3:0]
LPF2
Gyroscope Filtering Chain
Free-fall detection 6
Z
0g
Y
X
+ FF Threshold
- FF Threshold
FREE-
FALL
ZONE
FF Interrupt
FF Duration
• Recognize when the device is in free-fall
• Configurable parameters:
• FF Threshold
• FF Duration
Wake-up 7
+ WK Threshold
- WK Threshold
WK Interrupt
WK Duration
ACCELERATION
SLOPE
Slope(tn) = [ acc(tn) - acc(tn-1) ] / 2
acc(tn)
acc(tn-1)
• Recognize when the device is moved
• Configurable parameters:
• WK Threshold
• WK Duration
6D/4D orientation detection 8
X
YZ
X
YZ
X
YZ
X
Y
Z
X
Y
Z
X
YZ
(a)
(c)
(e)
(b)
(d)
(f)
• Detect the orientation of the device in space, enabling easy
implementation of energy-saving procedures and automatic image
rotation for mobile devices
• Configurable parameters:
• 6D Threshold (50°, 60°, 70°, 80°)
• 6D/4D detection mode
Single-tap and double-tap sensing 9
+ Tap Threshold
(a)
(b)
Slope
- Tap Threshold
Interrupt
SHOCK
QUIET DURATION
SHOCK
QUIET
Interrupt
QUIET QUIET
SHOCKSHOCK
SINGLE
TAP
DOUBLE
TAP
• Generate interrupt signal when the device is single/double tapped in any
direction (recommended XL ODR >= 400Hz)
• Configurable parameters:
• Tap Threshold
• Shock time
• Quiet time (Double tap)
• Duration time (Double tap)
Activity/Inactivity recognition 10
Interrupt
Slope
WAKE_DURSLEEP_DUR
INACTIVITY
STATUS
+ WK Threshold
ACTIVITY
STATUS
- WK Threshold
• Automatically decrease the accelerometer sampling rate to 12.5 Hz,
increasing the accelerometer ODR and bandwidth as soon as the
wake-up interrupt event has been detected
• Configurable parameters:
• WK Threshold
• Sleep Duration
• WK Duration
Pedometer functions:
Step counter & Step detector11
t
Amplitude
Actual THS
Minimum THS
Detected step
• A specific IP block dedicated to pedometer functions: the step detector
and the step counter. Pedometer functions work at 26 Hz (XL only)
• Configurable parameters:
• Number of debounce steps
• Debounce restart time
• Pedo Full-scale (2g / 4g)
• Minimum Threshold
Significant Motion Detection 12
• The Significant Motion function generates an interrupt when a
‘significant motion’, that could be due to a change in user location, is
detected. Significant Motion function works at 26 Hz (XL only)
• Configurable parameters:
• Number of steps to be performed before an SMD interrupt is generated
Relative Tilt 13
35º35º
START
POSITION
#0
FINAL
POSITION
#0
35º
START
POSITION
#1
35º
TILT
DETECTION
INTERRUPT
• The Tilt function allows detecting when an activity change occurs (e.g.
when phone is in a front pocket and the user goes from sitting to
standing or standing to sitting). Tilt algo works at 26Hz (XL only)
• First Tilt interrupt: tilt angle > 35° for a period of time >= 2 sec
• Next Tilt interrupts: as soon as tilt angle > 35° (no need to wait 2 sec)
Mode 2 - Sensor Hub mode (1/2) 14
LSM6DSL Ext Sensor
SDx
SCx
INT2
SDA
SCL
Data Ready
I2C MASTER I2C SLAVEExternal trigger is optional
1.5 kOhmR
Vdd_IO
1.5 kOhmR
Vdd_IO
External pull-up is optional
I2C / SPI
to HOST
• In Sensor Hub mode (Mode 2) up to 4 external sensors can be
connected to the I2C master interface
• External sensor data can also be stored in FIFO
• Magnetometer hard-iron / soft-iron correction
Mode 2 - Sensor Hub mode (2/2) 15
• I2C interface pass-through mode
LSM6DSL
SDx
SCx
INT2
Ext Sensor
SDA
SCL
1.5 kOhmR
Vdd_IO
1.5 kOhmR
Vdd_IO
SDA
SCL
PASS_THROUGH_MODE bit
10 kOhmR
Vdd_IO
10 kOhmR
Vdd_IOMCU
SDA
SCL
FIFO (1/2) 16
• LSM6DSL embeds an 4 kbyte first-in first-out buffer (FIFO) allowing to
limit intervention by the host processor and facilitate post-processing
data for event recognition
• The FIFO can be configured to store the following data:
• Gyroscope sensor data
• Accelerometer sensor data
• External sensors (connected to sensor hub interface) data
• Step counter and timestamp data
• Temperature sensor data
• Five different FIFO operating modes:
• Bypass mode (FIFO disabled)
• FIFO mode
• Continuous mode
• Continuous-to-FIFO mode
• Bypass-to-Continuous mode
FIFO (2/2) 17
• All data sets can be stored in FIFO at different ODRs, by setting the
decimation factors
• FIFO status signals:
• FIFO overrun events
• FIFO full status
• FIFO empty status
• FIFO threshold status
• Number of unread samples stored in the FIFO
• Stop on watermark
• ‘High part of data only’ mode
Thank You!
18