July 2009 Doc ID 15094 Rev 3 1/38
38
LIS331DLH
MEMS digital output motion sensor
ultra low-power high performance 3-axes “nano” accelerometer
Features
Wide supply voltage, 2.16 V to 3.6 V
Low voltage compatible IOs, 1.8 V
Ultra low-power mode consumption
down to 10 µA
±2g/±4g/±8g dynamically selectable full-scale
I2C/SPI digital output interface
16 bit data output
2 independent programmable interrupt
generators for free-fall and motion detection
Sleep to wake-up function
6D orientation detection
Embedded self-test
10000 g high shock survivability
ECOPACK® RoHS and “Green” compliant (see
Section 8)
Applications
Motion activated functions
Free-fall detection
Intelligent power saving for handheld devices
Pedometer
Display orientation
Gaming and virtual reality input devices
Impact recognition and logging
Vibration monitoring and compensation
Description
The LIS331DLH is an ultra low-power high
performance three axes linear accelerometer
belonging to the “nano” family, with digital I2C/SPI
serial interface standard output.
The device features ultra low-power operational
modes that allow advanced power saving and
smart sleep to wake-up functions.
The LIS331DLH has dynamically user selectable
full scales of ±2g/±4g/±8g and it is capable of
measuring accelerations with output data rates
from 0.5 Hz to 1 kHz.
The self-test capability allows the user to check
the functioning of the sensor in the final
application.
The device may be configured to generate
interrupt signal by inertial wake-up/free-fall events
as well as by the position of the device itself.
Thresholds and timing of interrupt generators are
programmable by the end user on the fly.
The LIS331DLH is available in small thin plastic
land grid array package (LGA) and it is
guaranteed to operate over an extended
temperature range from -40 °C to +85 °C.
LGA 16
(3x3x1 mm)
Table 1. Device summary
Order codes Temperature range [°C] Package Packaging
LIS331DLH -40 to +85 LGA 16 Tray
LIS331DLHTR -40 to +85 LGA 16 Tape and reel
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Contents LIS331DLH
2/38 Doc ID 15094 Rev 3
Contents
1 Block diagram and pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.2 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2 Mechanical and electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1 Mechanical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.3 Communication interface characteristics . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.3.1 SPI - serial peripheral interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.3.2 I2C - inter IC control interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.4 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.5 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.5.1 Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.5.2 Zero-g level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.5.3 Self-test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.5.4 Sleep to wake-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3 Functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.1 Sensing element . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.2 IC interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.3 Factory calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4 Application hints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.1 Soldering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5 Digital interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.1 I2C serial interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.1.1 I2C operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.2 SPI bus interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.2.1 SPI read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.2.2 SPI write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.2.3 SPI read in 3-wires mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
LIS331DLH Contents
Doc ID 15094 Rev 3 3/38
6 Register mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
7 Register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
7.1 WHO_AM_I (0Fh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
7.2 CTRL_REG1 (20h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
7.3 CTRL_REG2 (21h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
7.4 CTRL_REG3 [Interrupt CTRL register] (22h) . . . . . . . . . . . . . . . . . . . . . . 27
7.5 CTRL_REG4 (23h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
7.6 CTRL_REG5 (24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . h) 28
7.7 HP_FILTER_RESET (25h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
7.8 REFERENCE (26 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . h) 29
7.9 STATUS_REG (27h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
7.10 OUT_X_L (28h), OUT_X_H (29) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
7.11 OUT_Y_L (2Ah), OUT_Y_H (2Bh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
7.12 OUT_Z_L (2Ch), OUT_Z_H (2Dh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
7.13 INT1_CFG (30h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
7.14 INT1_SRC (31h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
7.15 INT1_THS (32h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
7.16 INT1_DURATION (33h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
7.17 INT2_CFG (34h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
7.18 INT2_SRC (35h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
7.19 INT2_THS (36h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
7.20 INT2_DURATION (37h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
8 Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
List of tables LIS331DLH
4/38 Doc ID 15094 Rev 3
List of tables
Table 1. Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Table 2. Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Table 3. Mechanical characteristics @ Vdd = 2.5 V, T = 25 °C unless otherwise noted . . . . . . . . . . 7
Table 4. Electrical characteristics @ Vdd = 2.5 V, T = 25 °C unless otherwise noted . . . . . . . . . . . . 8
Table 5. SPI slave timing values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Table 6. I2C slave timing values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Table 7. Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Table 8. Serial interface pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 9. Serial interface pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 10. SAD+Read/Write patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 11. Transfer when master is writing one byte to slave . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 12. Transfer when master is writing multiple bytes to slave:. . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Table 13. Transfer when master is receiving (reading) one byte of data from slave: . . . . . . . . . . . . . 17
Table 14. Transfer when Master is receiving (reading) multiple bytes of data from slave . . . . . . . . . 17
Table 15. Register address map. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Table 16. WHO_AM_I register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Table 17. CTRL_REG1 register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Table 18. CTRL_REG1 description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Table 19. Power mode and low-power output data rate configurations . . . . . . . . . . . . . . . . . . . . . . . 24
Table 20. Normal-mode output data rate configurations and low-pass cut-off frequencies . . . . . . . . 24
Table 21. CTRL_REG2 register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Table 22. CTRL_REG2 description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Table 23. High-pass filter mode configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Table 24. High-pass filter cut-off frequency configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Table 25. CTRL_REG3 register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Table 26. CTRL_REG3 description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Table 27. Data signal on INT 1 and INT 2 pad . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Table 28. CTRL_REG4 register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Table 29. CTRL_REG4 description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Table 30. CTRL_REG5 register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Table 31. CTRL_REG5 description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Table 32. Sleep to wake configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Table 33. REFERENCE register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Table 34. REFERENCE description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Table 35. STATUS_REG register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Table 36. STATUS_REG description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Table 37. INT1_CFG register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Table 38. INT1_CFG description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Table 39. Interrupt 1 source configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Table 40. INT1_SRC register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Table 41. INT1_SRC description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Table 42. INT1_THS register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Table 43. INT1_THS description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Table 44. INT1_DURATION register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Table 45. INT2_DURATION description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Table 46. INT2_CFG register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Table 47. INT2_CFG description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Table 48. Interrupt mode configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
LIS331DLH List of tables
Doc ID 15094 Rev 3 5/38
Table 49. INT2_SRC register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Table 50. INT2_SRC description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Table 51. INT2_THS register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Table 52. INT2_THS description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Table 53. INT2_DURATION register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Table 54. INT2_DURATION description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Table 55. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
List of figures LIS331DLH
6/38 Doc ID 15094 Rev 3
List of figures
Figure 1. Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Figure 2. Pin connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Figure 3. SPI slave timing diagram (2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Figure 4. I2C Slave timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Figure 5. LIS331DLH electrical connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Figure 6. Read and write protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 7. SPI read protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 8. Multiple bytes SPI read protocol (2 bytes example) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure 9. SPI write protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure 10. Multiple bytes SPI write protocol (2 bytes example) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 11. SPI read protocol in 3-wires mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 12. LGA16: mechanical data and package dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
LIS331DLH Block diagram and pin description
Doc ID 15094 Rev 3 7/38
1 Block diagram and pin description
1.1 Block diagram
Figure 1. Block diagram
1.2 Pin description
Figure 2. Pin connection
CHARGE
AMPLIFIER
Y+
Z+
Y-
Z-
a
X+
X-
I
2
C
SPI
CS
SCL/SPC
SDA/SDO/SDI
SDO/SA0
CONTROL LOGIC
&
INTERRUPT GEN.
INT 1
CLOCK
TRIMMING
CIRCUITS
REFERENCESELF TEST
CONTROL LOGIC
A/D
CONVERTER
INT 2
MUX
(TOP VIEW)
DIRECTION OF THE
DETECTABLE
ACCELERATIONS
1
5
9
13
(BOTTOM VIEW)
Y
1
X
Z
Pin 1 indicator
Block diagram and pin description LIS331DLH
8/38 Doc ID 15094 Rev 3
Table 2. Pin description
Pin# Name Function
1 Vdd_IO Power supply for I/O pins
2 NC Not connected
3 NC Not connected
4SCL
SPC
I2C serial clock (SCL)
SPI serial port clock (SPC)
5 GND 0V supply
6
SDA
SDI
SDO
I2C serial data (SDA)
SPI serial data input (SDI)
3-wire interface serial data output (SDO)
7SDO
SA0
SPI serial data output (SDO)
I2C less significant bit of the device address (SA0)
8CS
SPI enable
I2C/SPI mode selection (1: I2C mode; 0: SPI enabled)
9 INT 2 Inertial interrupt 2
10 Reserved Connect to GND
11 INT 1 Inertial interrupt 1
12 GND 0 V supply
13 GND 0 V supply
14 Vdd Power supply
15 Reserved Connect to Vdd
16 GND 0 V supply
LIS331DLH Mechanical and electrical specifications
Doc ID 15094 Rev 3 9/38
2 Mechanical and electrical specifications
2.1 Mechanical characteristics
Table 3. Mechanical characteristics @ Vdd = 2.5 V, T = 25 °C unless otherwise noted (1)
Symbol Parameter Test conditions Min. Typ.(2) Max. Unit
FS Measurement range(3)
FS bit set to 00 ±2.0
g
FS bit set to 01 ±4.0
FS bit set to 11 ±8.0
So Sensitivity
FS bit set to 00
12 bit representation 0.911.1
mg/digit
FS bit set to 01
12 bit representation 1.822.2
FS bit set to 11
12 bit representation 3.5 3.9 4.3
TCSo Sensitivity change vs
temperature FS bit set to 00 ±0.01 %/°C
Ty O f f Typical zero-g level offset
accuracy(4),(5) FS bit set to 00 ±20 mg
TCOff Zero-g level change vs
temperature Max delta from 25 °C ±0.1 mg/°C
An Acceleration noise density FS bit set to 00 218 µg/
Vst Self-test
output change(6),(7),(8)
FS bit set to 00
X axis 120 300 550 LSb
FS bit set to 00
Y axis 120 300 550 LSb
FS bit set to 00
Z axis 140 350 750 LSb
Top Operating temperature range -40 +85 °C
Wh Product weight 20 mgram
1. The product is factory calibrated at 2.5 V. The operational power supply range is from 2.16 V to 3.6 V.
2. Typical specifications are not guaranteed
3. Verified by wafer level test and measurement of initial offset and sensitivity
4. Typical zero-g level offset value after MSL3 preconditioning
5. Offset can be eliminated by enabling the built-in high pass filter
6. The sign of “Self-test output change” is defined by CTRL_REG4 STsign bit (Table 28), for all axes.
7.
Self-test output changes with the power supply. “Self-test output change” is defined as
OUTPUT[LSb]
(CTRL_REG4 ST bit=1)
- OUTPUT[LSb](CTRL_REG4 ST bit=0). 1LSb=4g/4096 at 12bit representation, ±2 g Full-scale
8. Output data reach 99% of final value after 1/ODR+ 1 ms when enabling self-test mode, due to device filtering
Hz
Mechanical and electrical specifications LIS331DLH
10/38 Doc ID 15094 Rev 3
2.2 Electrical characteristics
Table 4. Electrical characteristics @ Vdd = 2.5 V, T = 25 °C unless otherwise noted (1)
Symbol Parameter Test conditions Min. Typ.(2) Max. Unit
Vdd Supply voltage 2.16 2.5 3.6 V
Vdd_IO I/O pins supply voltage(3) 1.71 Vdd+0.1 V
Idd Current consumption
in normal mode 250 µA
IddLP Current consumption
in low-power mode 10 µA
IddPdn Current consumption in
power-down mode A
VIH Digital high level input
voltage 0.8*Vdd_IO V
VIL Digital low level input voltage 0.2*Vdd_IO V
VOH High level output voltage 0.9*Vdd_IO V
VOL Low level output voltage 0.1*Vdd_IO V
ODR Output data rate
in normal mode
DR bit set to 00 50
Hz
DR bit set to 01 100
DR bit set to 10 400
DR bit set to 11 1000
ODRLP
Output data rate
in low-power mode
PM bit set to 010 0.5
Hz
PM bit set to 011 1
PM bit set to 100 2
PM bit set to 101 5
PM bit set to 110 10
BW System bandwidth(4) ODR/2 Hz
Ton Turn-on time(5) ODR = 100 Hz 1/ODR+1ms s
Top Operating temperature range -40 +85 °C
1. The product is factory calibrated at 2.5 V. The operational power supply range is from 2.16 V to 3.6 V.
2. Typical specification are not guaranteed
3. It is possible to remove Vdd maintaining Vdd_IO without blocking the communication busses, in this condition the
measurement chain is powered off.
4. Refer to Table 20 for filter cut-off frequency
5. Time to obtain valid data after exiting power-down mode
LIS331DLH Mechanical and electrical specifications
Doc ID 15094 Rev 3 11/38
2.3 Communication interface characteristics
2.3.1 SPI - serial peripheral interface
Subject to general operating conditions for Vdd and Top.
Figure 3. SPI slave timing diagram (2)
1. Values are guaranteed at 10 MHz clock frequency for SPI with both 4 and 3 wires, based on characterization results, not
tested in production
2. Measurement points are done at 0.2·Vdd_IO and 0.8·Vdd_IO, for both Input and output port
3. When no communication is on-going, data on CS, SPC, SDI and SDO are driven by internal pull-up resistors
Table 5. SPI slave timing values
Symbol Parameter
Value (1)
Unit
Min Max
tc(SPC) SPI clock cycle 100 ns
fc(SPC) SPI clock frequency 10 MHz
tsu(CS) CS setup time 6
ns
th(CS) CS hold time 8
tsu(SI) SDI input setup time 5
th(SI) SDI input hold time 15
tv(SO) SDO valid output time 50
th(SO) SDO output hold time 9
tdis(SO) SDO output disable time 50
SPC
CS
SDI
SDO
t
su(CS)
t
v(SO)
t
h(SO)
t
h(SI)
t
su(SI)
t
h(CS)
t
dis(SO)
t
c(SPC)
MSB IN
MSB OUT LSB OUT
LSB IN
(3)
(3)
(3)
(3)
(3)
(3)
(3)
(3)
Mechanical and electrical specifications LIS331DLH
12/38 Doc ID 15094 Rev 3
2.3.2 I2C - inter IC control interface
Subject to general operating conditions for Vdd and top.
Figure 4. I2C Slave timing diagram (a)
Table 6. I2C slave timing values
Symbol Parameter
I2C standard mode (1) I2C fast mode (1)
Unit
Min Max Min Max
f(SCL) SCL clock frequency 0 100 0 400 KHz
tw(SCLL) SCL clock low time 4.7 1.3
µs
tw(SCLH) SCL clock high time 4.0 0.6
tsu(SDA) SDA setup time 250 100 ns
th(SDA) SDA data hold time 0.01 3.45 0.01 0.9 µs
tr(SDA) tr(SCL) SDA and SCL rise time 1000 20 + 0.1Cb (2) 300
ns
tf(SDA) tf(SCL) SDA and SCL fall time 300 20 + 0.1Cb (2) 300
th(ST) START condition hold time 4 0.6
µs
tsu(SR) Repeated START condition
setup time 4.7 0.6
tsu(SP) STOP condition setup time 4 0.6
tw(SP:SR) Bus free time between STOP
and START condition 4.7 1.3
1. Data based on standard I2C protocol requirement, not tested in production
2. Cb = total capacitance of one bus line, in pF
a. Measurement points are done at 0.2·Vdd_IO and 0.8·Vdd_IO, for both port
SDA
SCL
t
f(SDA)
t
su(SP)
t
w(SCLL)
t
su(SDA)
t
r(SDA)
t
su(SR)
t
h(ST)
t
w(SCLH)
t
h(SDA)
t
r(SCL)
t
f(SCL)
t
w(SP:SR)
START
REPEATED
START
STOP
STAR
T
LIS331DLH Mechanical and electrical specifications
Doc ID 15094 Rev 3 13/38
2.4 Absolute maximum ratings
Stresses above those listed as “absolute maximum ratings” may cause permanent damage
to the device. This is a stress rating only and functional operation of the device under these
conditions is not implied. Exposure to maximum rating conditions for extended periods may
affect device reliability.
Note: Supply voltage on any pin should never exceed 6.0 V
Table 7. Absolute maximum ratings
Symbol Ratings Maximum value Unit
Vdd Supply voltage -0.3 to 6 V
Vdd_IO I/O pins Supply voltage -0.3 to 6 V
Vin Input voltage on any control pin
(CS, SCL/SPC, SDA/SDI/SDO, SDO/SA0) -0.3 to Vdd_IO +0.3 V
APOW Acceleration (any axis, powered, Vdd = 2.5 V) 3000 g for 0.5 ms
10000 g for 0.1 ms
AUNP Acceleration (any axis, unpowered) 3000 g for 0.5 ms
10000 g for 0.1 ms
TOP Operating temperature range -40 to +85 °C
TSTG Storage temperature range -40 to +125 °C
ESD Electrostatic discharge protection
4 (HBM) kV
1.5 (CDM) kV
200 (MM) V
This is a mechanical shock sensitive device, improper handling can cause permanent
damages to the part
This is an ESD sensitive device, improper handling can cause permanent damages to
the part
Mechanical and electrical specifications LIS331DLH
14/38 Doc ID 15094 Rev 3
2.5 Terminology
2.5.1 Sensitivity
Sensitivity describes the gain of the sensor and can be determined e.g. by applying 1 g
acceleration to it. As the sensor can measure DC accelerations this can be done easily by
pointing the axis of interest towards the center of the earth, noting the output value, rotating
the sensor by 180 degrees (pointing to the sky) and noting the output value again. By doing
so, ±1 g acceleration is applied to the sensor. Subtracting the larger output value from the
smaller one, and dividing the result by 2, leads to the actual sensitivity of the sensor. This
value changes very little over temperature and also time. The sensitivity tolerance describes
the range of Sensitivities of a large population of sensors.
2.5.2 Zero-g level
Zero-g level offset (TyOff) describes the deviation of an actual output signal from the ideal
output signal if no acceleration is present. A sensor in a steady state on a horizontal surface
will measure 0 g in X axis and 0 g in Y axis whereas the Z axis will measure 1 g. The output
is ideally in the middle of the dynamic range of the sensor (content of OUT registers 00h,
data expressed as 2’s complement number). A deviation from ideal value in this case is
called Zero-g offset. Offset is to some extent a result of stress to MEMS sensor and
therefore the offset can slightly change after mounting the sensor onto a printed circuit
board or exposing it to extensive mechanical stress. Offset changes little over temperature,
see “Zero-g level change vs. temperature”. The Zero-g level tolerance (TyOff) describes the
standard deviation of the range of Zero-g levels of a population of sensors.
2.5.3 Self-test
Self-test allows to check the sensor functionality without moving it. The self-test function is
off when the self-test bit (ST) of CTRL_REG4 (control register 4) is programmed to ‘0‘.
When the self-test bit of CTRL_REG4 is programmed to ‘1‘ an actuation force is applied to
the sensor, simulating a definite input acceleration. In this case the sensor outputs will
exhibit a change in their DC levels which are related to the selected full scale through the
device sensitivity. When 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
Table 3, then the sensor is working properly and the parameters of the interface chip are
within the defined specifications.
2.5.4 Sleep to wake-up
The “sleep to wake-up” function, in conjunction with low-power mode, allows to further
reduce the system power consumption and develop new smart applications.
LIS331DLH may be set in a low-power operating mode, characterized by lower date rates
refreshments. In this way the device, even if sleeping, keep on sensing acceleration and
generating interrupt requests.
When the “sleep to wake-up” function is activated, LIS331DLH is able to automatically
wake-up as soon as the interrupt event has been detected, increasing the output data rate
and bandwidth.
With this feature the system may be efficiently switched from low-power mode to full-
performance depending on user-selectable positioning and acceleration events, thus
ensuring power saving and flexibility.
LIS331DLH Functionality
Doc ID 15094 Rev 3 15/38
3 Functionality
The LIS331DLH is a “nano”, low-power, digital output 3-axis linear accelerometer packaged
in a LGA package. The complete device includes a sensing element and an IC interface
able to take the information from the sensing element and to provide a signal to the external
world through an I2C/SPI serial interface.
3.1 Sensing element
A proprietary process is used to create a surface micro-machined accelerometer. The
technology allows to carry out suspended silicon structures which are attached to the
substrate in a few points called anchors and are free to move in the direction of the sensed
acceleration. To be compatible with the traditional packaging techniques a cap is placed on
top of the sensing element to avoid blocking the moving parts during the moulding phase of
the plastic encapsulation.
When an acceleration is applied to the sensor the proof mass displaces from its nominal
position, causing an imbalance in the capacitive half-bridge. This imbalance is measured
using charge integration in response to a voltage pulse applied to the capacitor.
At steady state the nominal value of the capacitors are few pF and when an acceleration is
applied the maximum variation of the capacitive load is in the fF range.
3.2 IC interface
The complete measurement chain is composed by a low-noise capacitive amplifier which
converts the capacitive unbalancing of the MEMS sensor into an analog voltage that is
finally available to the user by an analog-to-digital converter.
The acceleration data may be accessed through an I2C/SPI interface thus making the
device particularly suitable for direct interfacing with a microcontroller.
The LIS331DLH features a Data-Ready signal (RDY) which indicates when a new set of
measured acceleration data is available thus simplifying data synchronization in the digital
system that uses the device.
The LIS331DLH may also be configured to generate an inertial Wake-Up and Free-Fall
interrupt signal accordingly to a programmed acceleration event along the enabled axes.
Both Free-Fall and Wake-Up can be available simultaneously on two different pins.
3.3 Factory calibration
The IC interface is factory calibrated for sensitivity (So) and Zero-g level (TyOff).
The trimming values are stored inside the device in a non volatile memory. Any time the
device is turned on, the trimming parameters are downloaded into the registers to be used
during the active operation. This allows to use the device without further calibration.
Application hints LIS331DLH
16/38 Doc ID 15094 Rev 3
4 Application hints
Figure 5. LIS331DLH electrical connection
The device core is supplied through Vdd line while the I/O pads are supplied through
Vdd_IO line. Power supply decoupling capacitors (100 nF ceramic, 10 µF Aluminum) should
be placed as near as possible to the pin 14 of the device (common design practice).
All the voltage and ground supplies must be present at the same time to have proper
behavior of the IC (refer to Figure 5). It is possible to remove Vdd maintaining Vdd_IO
without blocking the communication bus, in this condition the measurement chain is
powered off.
The functionality of the device and the measured acceleration data is selectable and
accessible through the I2C or SPI interfaces.When using the I2C, CS must be tied high.
The functions, the threshold and the timing of the two interrupt pins (INT 1 and INT 2) can be
completely programmed by the user through the I2C/SPI interface.
4.1 Soldering information
The LGA package is compliant with the ECOPACK®, RoHS and “Green” standard.
It is qualified for soldering heat resistance according to JEDEC J-STD-020C.
Leave “pin 1 indicator” unconnected during soldering.
Land pattern and soldering recommendations are available at www.st.com.
CS
10µF
Vdd
100nF
GND
Vdd_IO
SDO/SA0
SDA/SDI/SDO
INT 1
SCL/SPC
Digital signal from/to signal controller.Signal’s levels are defined by proper selection of Vdd_IO
1
5
8
13
TOP VIEW
6
9
1416
9
5
INT 2
LIS331DLH Digital interfaces
Doc ID 15094 Rev 3 17/38
5 Digital interfaces
The registers embedded inside the LIS331DLH may be accessed through both the I2C and
SPI serial interfaces. The latter may be SW configured to operate either in 3-wire or 4-wire
interface mode.
The serial interfaces are mapped onto the same pads. To select/exploit the I2C interface, CS
line must be tied high (i.e. connected to Vdd_IO).
5.1 I2C serial interface
The LIS331DLH I2C is a bus slave. The I2C is employed to write data into registers whose
content can also be read back.
The relevant I2C terminology is given in the table below.
There are two signals associated with the I2C bus: the serial clock line (SCL) and the serial
data line (SDA). The latter is a bidirectional line used for sending and receiving the data
to/from the interface. Both the lines are connected to Vdd_IO through a pull-up resistor
embedded inside the LIS331DLH. When the bus is free both the lines are high.
The I2C interface is compliant with fast mode (400 kHz) I2C standards as well as with the
normal mode.
Table 8. Serial interface pin description
Pin name Pin description
CS SPI enable
I2C/SPI mode selection (1: I2C mode; 0: SPI enabled)
SCL
SPC
I2C serial clock (SCL)
SPI serial port clock (SPC)
SDA
SDI
SDO
I2C serial data (SDA)
SPI serial data input (SDI)
3-wire interface serial data output (SDO)
SA0
SDO
I2C less significant bit of the device address (SA0)
SPI serial data output (SDO)
Table 9. Serial interface pin description
Term Description
Transmitter The device which sends data to the bus
Receiver The device which receives data from the bus
Master The device which initiates a transfer, generates clock signals and terminates a
transfer
Slave The device addressed by the master
Digital interfaces LIS331DLH
18/38 Doc ID 15094 Rev 3
5.1.1 I2C operation
The transaction on the bus is started through a START (ST) signal. A START condition is
defined as a HIGH to LOW transition on the data line while the SCL line is held HIGH. After
this has been transmitted by the Master, the bus is considered busy. The next byte of data
transmitted after the start condition contains the address of the slave in the first 7 bits and
the eighth bit tells whether the Master is receiving data from the slave or transmitting data to
the slave. When an address is sent, each device in the system compares the first seven bits
after a start condition with its address. If they match, the device considers itself addressed
by the Master.
The Slave ADdress (SAD) associated to the LIS331DLH is 001100xb. SDO/SA0 pad can be
used to modify less significant bit of the device address. If SA0 pad is connected to voltage
supply, LSb is ‘1’ (address 0011001b) else if SA0 pad is connected to ground, LSb value is
‘0’ (address 0011000b). This solution permits to connect and address two different
accelerometers to the same I2C lines.
Data transfer with acknowledge is mandatory. The transmitter must release the SDA line
during the acknowledge pulse. The receiver must then pull the data line LOW so that it
remains stable low during the HIGH period of the acknowledge clock pulse. A receiver which
has been addressed is obliged to generate an acknowledge after each byte of data
received.
The I2C embedded inside the LIS331DLH behaves like a slave device and the following
protocol must be adhered to. After the start condition (ST) a slave address is sent, once a
slave acknowledge (SAK) has been returned, a 8-bit sub-address (SUB) is transmitted: the
7 LSb represent the actual register address while the MSB enables address auto increment.
If the MSb of the SUB field is ‘1’, the SUB (register address) is automatically increased to
allow multiple data read/write.
The slave address is completed with a Read/Write bit. If the bit was ‘1’ (Read), a repeated
START (SR) condition must be issued after the two sub-address bytes; if the bit is ‘0’ (Write)
the Master will transmit to the slave with direction unchanged. Table explains how the
SAD+Read/Write bit pattern is composed, listing all the possible configurations.
Table 10. SAD+Read/Write patterns
Command SAD[6:1] SAD[0] = SA0 R/W SAD+R/W
Read 001100 0 1 00110001 (31h)
Write 001100 0 0 00110000 (30h)
Read 001100 1 1 00110011 (33h)
Write 001100 1 0 00110010 (32h)
Table 11. Transfer when master is writing one byte to slave
Master ST SAD + W SUB DATA SP
Slave SAK SAK SAK
LIS331DLH Digital interfaces
Doc ID 15094 Rev 3 19/38
Data are transmitted in byte format (DATA). Each data transfer contains 8 bits. The number
of bytes transferred per transfer is unlimited. Data is transferred with the Most Significant bit
(MSb) first. If a receiver can’t receive another complete byte of data until it has performed
some other function, it can hold the clock line, SCL LOW to force the transmitter into a wait
state. Data transfer only continues when the receiver is ready for another byte and releases
the data line. If a slave receiver doesn’t acknowledge the slave address (i.e. it is not able to
receive because it is performing some real time function) the data line must be left HIGH by
the slave. The Master can then abort the transfer. A LOW to HIGH transition on the SDA line
while the SCL line is HIGH is defined as a STOP condition. Each data transfer must be
terminated by the generation of a STOP (SP) condition.
In order to read multiple bytes, it is necessary to assert the most significant bit of the sub-
address field. In other words, SUB(7) must be equal to 1 while SUB(6-0) represents the
address of first register to be read.
In the presented communication format MAK is Master acknowledge and NMAK is no
master acknowledge.
5.2 SPI bus interface
The LIS331DLH SPI is a bus slave. The SPI allows to write and read the registers of the
device.
The Serial Interface interacts with the outside world with 4 wires: CS, SPC, SDI and SDO.
Table 12. Transfer when master is writing multiple bytes to slave:
Master ST SAD + W SUB DATA DATA SP
Slave SAK SAK SAK SAK
Table 13. Transfer when master is receiving (reading) one byte of data from slave:
Master ST SAD + W SUB SR SAD + R NMAK SP
Slave SAK SAK SAK DATA
Table 14. Transfer when Master is receiving (reading) multiple bytes of data from slave
Master ST SAD+W SUB SR SAD+R MAK MAK NMAK SP
Slave SAK SAK SAK DATA DATA DATA
Digital interfaces LIS331DLH
20/38 Doc ID 15094 Rev 3
Figure 6. Read and write protocol
CS is the serial port enable and it is controlled by the SPI master. It goes low at the start of
the transmission and goes back high at the end. SPC is the serial port clock and it is
controlled by the SPI master. It is stopped high when CS is high (no transmission). SDI and
SDO are respectively the serial port data input and output. Those lines are driven at the
falling edge of SPC and should be captured at the rising edge of SPC.
Both the read register and write register commands are completed in 16 clock pulses or in
multiple of 8 in case of multiple bytes read/write. Bit duration is the time between two falling
edges of SPC. The first bit (bit 0) starts at the first falling edge of SPC after the falling edge
of CS while the last bit (bit 15, bit 23, ...) starts at the last falling edge of SPC just before the
rising edge of CS.
bit 0: RW bit. When 0, the data DI(7:0) is written into the device. When 1, the data DO(7:0)
from the device is read. In latter case, the chip will drive SDO at the start of bit 8.
bit 1: MS bit. When 0, the address will remain unchanged in multiple read/write commands.
When 1, the address is auto incremented in multiple read/write commands.
bit 2-7: address AD(5:0). This is the address field of the indexed register.
bit 8-15: data DI(7:0) (write mode). This is the data that is written into the device (MSb first).
bit 8-15: data DO(7:0) (read mode). This is the data that is read from the device (MSb first).
In multiple read/write commands further blocks of 8 clock periods will be added. When MS
bit is ‘0’ the address used to read/write data remains the same for every block. When MS bit
is ‘1’ the address used to read/write data is increased at every block.
The function and the behavior of SDI and SDO remain unchanged.
5.2.1 SPI read
Figure 7. SPI read protocol
CS
SPC
SDI
SDO
RW
AD5 AD4 AD3 AD2 AD1 AD0
DI7DI6DI5DI4DI3DI2DI1DI0
DO7DO6DO5DO4DO3DO2DO1DO0
MS
CS
SPC
SDI
SDO
RW
DO7 DO6 DO5 DO4 DO3 DO2 DO1 DO0
AD5 AD4 AD3 AD2 AD1 AD0
MS
LIS331DLH Digital interfaces
Doc ID 15094 Rev 3 21/38
The SPI Read command is performed with 16 clock pulses. Multiple byte read command is
performed adding blocks of 8 clock pulses at the previous one.
bit 0: READ bit. The value is 1.
bit 1: MS bit. When 0 do not increment address, when 1 increment address in multiple
reading.
bit 2-7: address AD(5:0). This is the address field of the indexed register.
bit 8-15: data DO(7:0) (read mode). This is the data that will be read from the device (MSb
first).
bit 16-... : data DO(...-8). Further data in multiple byte reading.
Figure 8. Multiple bytes SPI read protocol (2 bytes example)
5.2.2 SPI write
Figure 9. SPI write protocol
The SPI Write command is performed with 16 clock pulses. Multiple byte write command is
performed adding blocks of 8 clock pulses at the previous one.
bit 0: WRITE bit. The value is 0.
bit 1: MS bit. When 0 do not increment address, when 1 increment address in multiple
writing.
bit 2 -7: address AD(5:0). This is the address field of the indexed register.
bit 8-15: data DI(7:0) (write mode). This is the data that is written inside the device (MSb
first).
bit 16-... : data DI(...-8). Further data in multiple byte writing.
CS
SPC
SDI
SDO
RW
DO7DO6DO5DO4DO3DO2DO1DO0
AD5 AD4 AD3 AD2 AD1 AD0
DO15 DO14 DO13 DO12 DO11 DO10 DO9 DO8
MS
CS
SPC
SDI
RW DI7 DI6 DI5 DI4 DI3 DI2 DI1 DI0
AD5 AD4 AD3 AD2 AD1 AD0MS
Digital interfaces LIS331DLH
22/38 Doc ID 15094 Rev 3
Figure 10. Multiple bytes SPI write protocol (2 bytes example)
5.2.3 SPI read in 3-wires mode
3-wires mode is entered by setting to ‘1’ bit SIM (SPI serial interface mode selection) in
CTRL_REG4.
Figure 11. SPI read protocol in 3-wires mode
The SPI read command is performed with 16 clock pulses:
bit 0: READ bit. The value is 1.
bit 1: MS bit. When 0 do not increment address, when 1 increment address in multiple
reading.
bit 2-7: address AD(5:0). This is the address field of the indexed register.
bit 8-15: data DO(7:0) (read mode). This is the data that is read from the device (MSb first).
Multiple read command is also available in 3-wires mode.
CS
SPC
SDI
RW
AD5 AD4 AD3 AD2 AD1 AD0
DI7 DI6 DI5 DI4 DI3 DI2 DI1 DI0 DI15 DI14 DI13 DI12 DI11 DI10 DI9 DI8
MS
CS
SPC
SDI/O
RW DO7 DO6 DO5 DO4 DO3 DO2 DO1 DO0
AD5 AD4 AD3 AD2 AD1 AD0
MS
LIS331DLH Register mapping
Doc ID 15094 Rev 3 23/38
6 Register mapping
The table given below provides a listing of the 8 bit registers embedded in the device and
the related addresses:
Registers marked as Reserved must not be changed. The writing to those registers may
cause permanent damages to the device.
Table 15. Register address map
Name Type
Register address
Default Comment
Hex Binary
Reserved (do not modify) 00 - 0E Reserved
WHO_AM_I r 0F 000 1111 00110010 Dummy register
Reserved (do not modify) 10 - 1F Reserved
CTRL_REG1 rw 20 010 0000 00000111
CTRL_REG2 rw 21 010 0001 00000000
CTRL_REG3 rw 22 010 0010 00000000
CTRL_REG4 rw 23 010 0011 00000000
CTRL_REG5 rw 24 010 0100 00000000
HP_FILTER_RESET r 25 010 0101 Dummy register
REFERENCE rw 26 010 0110 00000000
STATUS_REG r 27 010 0111 00000000
OUT_X_L r 28 010 1000 output
OUT_X_H r 29 010 1001 output
OUT_Y_L r 2A 010 1010 output
OUT_Y_H r 2B 010 1011 output
OUT_Z_L r 2C 010 1100 output
OUT_Z_H r 2D 010 1101 output
Reserved (do not modify) 2E - 2F Reserved
INT1_CFG rw 30 011 0000 00000000
INT1_SOURCE r 31 011 0001 00000000
INT1_THS rw 32 011 0010 00000000
INT1_DURATION rw 33 011 0011 00000000
INT2_CFG rw 34 011 0100 00000000
INT2_SOURCE r 35 011 0101 00000000
INT2_THS rw 36 011 0110 00000000
INT2_DURATION rw 37 011 0111 00000000
Reserved (do not modify) 38 - 3F Reserved
Register mapping LIS331DLH
24/38 Doc ID 15094 Rev 3
The content of the registers that are loaded at boot should not be changed. They contain the
factory calibration values. Their content is automatically restored when the device is
powered-up.
LIS331DLH Register description
Doc ID 15094 Rev 3 25/38
7 Register description
The device contains a set of registers which are used to control its behavior and to retrieve
acceleration data. The registers address, made of 7 bits, is used to identify them and to
write the data through serial interface.
7.1 WHO_AM_I (0Fh)
Device identification register.
This register contains the device identifier that for LIS331DLH is set to 32h.
7.2 CTRL_REG1 (20h)
PM bits allow to select between power-down and two operating active modes. The device is
in power-down mode when PD bits are set to “000” (default value after boot). Table 19
shows all the possible power mode configurations and respective output data rates. Output
data in the low-power modes are computed with low-pass filter cut-off frequency defined by
DR1, DR0 bits.
DR bits, in the normal-mode operation, select the data rate at which acceleration samples
are produced. In low-power mode they define the output data resolution. Table 20 shows all
the possible configuration for DR1 and DR0 bits.
Table 16. WHO_AM_I register
00110010
Table 17. CTRL_REG1 register
PM2 PM1 PM0 DR1 DR0 Zen Yen Xen
Table 18. CTRL_REG1 description
PM2 - PM0 Power mode selection. Default value: 000
(000: Power-down; Others: refer to Table 19)
DR1, DR0 Data rate selection. Default value: 00
(00:50 Hz; Others: refer to Table 20)
Zen Z axis enable. Default value: 1
(0: Z axis disabled; 1: Z axis enabled)
Ye n Y axis enable. Default value: 1
(0: Y axis disabled; 1: Y axis enabled)
Xen X axis enable. Default value: 1
(0: X axis disabled; 1: X axis enabled)