0330.SB0.124 - Bosch Sensortec

Data sheet

BMC050

Electronic Compass

BMC050: Data sheet

Document revision

1.0

Document release date

October 28th, 2011

Document number

BST-BMC050-DS000-10

Technical reference code(s)

0 273 141 124

Notes

Data in this document are preliminary and subject to change without

notice. Product photos and pictures are for illustration purposes only and

may differ from the real product‟s appearance.

This document is confidential and under NDA.

Bosch Sensortec

Datasheet

BMC050 Electronic Compass

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third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.

Note: Specifications within this document are subject to change without notice. Not intended for publication.

BMC050

ELECTRONIC COMPASS WITH THREE-AXIS MAGNETIC FIELD SENSOR

AND THREE-AXIS ACCELEROMETER

Key features

Three-axis magnetic field sensor and three-axis accelerometer in one package

 Accelerometer can still be used independently from magnetometer operation

 Ultra-Small package LGA package (16 pins), footprint 3mm x 3mm, height

0.95mm

 Digital interface SPI (4-wire, 3-wire), I²C, 4 interrupt pins

(2 acceleration sensor, 2 magnetic sensor interrupt pins)

 Low voltage operation VDD supply voltage range: 1.62V to 3.6V

VDDIO interface voltage range: 1.2V to 3.6V

 Flexible functionality Acceleration ranges ±2g / ±4g / ±8g / ±16g

Acceleration Low-pass filter bandwidths 1 kHz - <8Hz

Magnetic field range typical ±1000µT

Magnetic field resolution of ~0.3µT

 On-chip interrupt controller Motion-triggered interrupt-signal generation for

- new data (separate for accelerometer and magnetometer)

- any-motion (slope) detection

- tap sensing (single tap / double tap)

- orientation recognition

- flat detection

- low-g/high-g detection

- magnetic Low-/High-Threshold detection

 Ultra-low power Low current consumption (190µA @ 10 Hz including

accelerometer and magnetic sensor in low power preset),

short wake-up time, advanced features for system power

management

 Temperature range -40 °C … +85 °C

 RoHS compliant, halogen-free

Typical applications

 Tilt-compensated electronic compass for map rotation, navigation and augmented reality

 6-axis orientation for gaming

 Display profile switching

 Menu scrolling, tap / double tap sensing

 Pedometer / step counting

 Free-fall detection

 Drop detection for warranty logging

 Advanced system power management for mobile applications

Datasheet

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third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.

Note: Specifications within this document are subject to change without notice. Not intended for publication.

General Description

The BMC050 is an integrated electronic compass solution for consumer market applications. It

comprises a leading edge triaxial, low-g acceleration sensor and an ultra-low power, high

precision triaxial magnetic field sensor. It allows measurements of acceleration and magnetic

field in three perpendicular axes. Performance and features of both sensing technologies are

carefully tuned and perfectly match the demanding requirements of all 6-axis mobile

applications such as electronic compass, navigation or augmented reality.

An evaluation circuitry (ASIC) converts the output of the micromechanical sensing structures

(MEMS) to digital results which can be read out over the industry standard digital interfaces.

Package and interfaces of the BMC050 have been designed to match a multitude of hardware

requirements. As the sensor features an ultra-small footprint and a flat package, it is ingeniously

suited for mobile applications.

The BMC050 offers ultra-low voltage operation (VDD voltage range from 1.62V to 3.6V, VDDIO

voltage range 1.2V to 3.6V) and can be programmed to optimize functionality, performance and

power consumption in customer specific applications. The programmable interrupt engine sets

new standards in terms of flexibility.

The BMC050 senses orientation, tilt, motion, shock, vibration and heading in cell phones,

handhelds, computer peripherals, man-machine interfaces, virtual reality features and game

controllers.

Datasheet

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third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.

Note: Specifications within this document are subject to change without notice. Not intended for publication.

Index of Contents

1. SPECIFICATION ........................................................................................................................ 7

1.1 COMPASS ELECTRICAL SPECIFICATION ................................................................................. 7

1.2 ACCELEROMETER SPECIFICATION ........................................................................................ 7

1.3 MAGNETOMETER SPECIFICATION ......................................................................................... 9

2. ABSOLUTE MAXIMUM RATINGS .......................................................................................... 12

3. BLOCK DIAGRAM ................................................................................................................... 13

4. FUNCTIONAL DESCRIPTION ................................................................................................. 14

4.1 POWER MANAGEMENT ....................................................................................................... 14

4.2 PROTOCOL SELECTION ...................................................................................................... 14

4.3 POWER MODES ................................................................................................................. 15

4.3.1 ACCELEROMETER POWER MODES ................................................................................................. 15

4.3.2 MAGNETOMETER POWER MODES .................................................................................................. 18

4.3.3 BMC050 OVERALL POWER CONSUMPTION .................................................................................... 21

4.4 SENSOR DATA .................................................................................................................. 21

4.4.1 ACCELERATION DATA ................................................................................................................... 21

4.4.2 TEMPERATURE DATA .................................................................................................................... 23

4.4.3 MAGNETIC FIELD DATA .................................................................................................................. 23

4.4.4 MAGNETIC FIELD DATA TEMPERATURE COMPENSATION................................................................... 25

4.5 SELF-TEST ....................................................................................................................... 26

4.5.1 ACCELEROMETER SELF-TEST ........................................................................................................ 26

4.5.2 MAGNETOMETER SELF-TEST ......................................................................................................... 26

4.6 ACCELEROMETER OFFSET COMPENSATION ......................................................................... 28

4.6.1 SLOW COMPENSATION .................................................................................................................. 29

4.6.2 FAST COMPENSATION ................................................................................................................... 30

4.6.3 MANUAL COMPENSATION .............................................................................................................. 31

4.6.4 INLINE CALIBRATION ..................................................................................................................... 31

4.7 NON-VOLATILE MEMORY .................................................................................................... 32

4.7.1 ACCELEROMETER NON-VOLATILE MEMORY .................................................................................... 32

4.7.2 MAGNETOMETER NON-VOLATILE MEMORY ..................................................................................... 32

4.8 ACCELEROMETER INTERRUPT CONTROLLER ....................................................................... 33

4.8.1 GENERAL FEATURES .................................................................................................................... 33

4.8.2 MAPPING (INTTYPE TO INT PIN#) .................................................................................................. 34

4.8.3 ELECTRICAL BEHAVIOR (INT PIN# TO OPEN-DRIVE OR PUSH-PULL) .................................................. 34

4.8.4 NEW DATA INTERRUPT .................................................................................................................. 35

4.8.5 ANY-MOTION (SLOPE) DETECTION ................................................................................................. 35

4.8.6 TAP SENSING ............................................................................................................................... 36

4.8.7 ORIENTATION RECOGNITION ......................................................................................................... 39

4.8.8 FLAT DETECTION .......................................................................................................................... 43

4.8.9 LOW-G INTERRUPT ....................................................................................................................... 43

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third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.

Note: Specifications within this document are subject to change without notice. Not intended for publication.

4.8.10 HIGH-G INTERRUPT .................................................................................................................... 44

4.9 MAGNETOMETER INTERRUPT CONTROLLER ........................................................................ 45

4.9.1 GENERAL FEATURES .................................................................................................................... 45

4.9.2 ELECTRICAL BEHAVIOR OF MAGNETIC INTERRUPT PINS ................................................................... 46

4.9.3 DATA READY / DRDY INTERRUPT .................................................................................................. 46

4.9.4 LOW-THRESHOLD INTERRUPT........................................................................................................ 47

4.9.5 HIGH-THRESHOLD INTERRUPT ....................................................................................................... 48

4.9.6 OVERFLOW .................................................................................................................................. 48

5. ACCELEROMETER REGISTER DESCRIPTION.................................................................... 49

5.1 GENERAL REMARKS .......................................................................................................... 49

5.2 REGISTER MAP ................................................................................................................. 50

5.3 CHIP ID ............................................................................................................................ 50

5.4 ACCELERATION DATA ........................................................................................................ 51

5.5 TEMPERATURE DATA ......................................................................................................... 53

5.6 STATUS REGISTERS .......................................................................................................... 53

5.7 G-RANGE SELECTION ......................................................................................................... 55

5.8 BANDWIDTHS .................................................................................................................... 55

5.9 POWER MODES ................................................................................................................. 55

5.10 SPECIAL CONTROL SETTINGS ........................................................................................... 56

5.11 INTERRUPT SETTINGS ...................................................................................................... 56

5.12 SELF-TEST ..................................................................................................................... 64

5.13 NON-VOLATILE MEMORY CONTROL (EEPROM CONTROL) .................................................. 65

5.14 INTERFACE CONFIGURATION ............................................................................................ 66

5.15 OFFSET COMPENSATION.................................................................................................. 67

6. MAGNETOMETER REGISTER DESCRIPTION ..................................................................... 69

6.1 GENERAL REMARKS .......................................................................................................... 69

6.2 REGISTER MAP ................................................................................................................. 69

6.3 CHIP ID ............................................................................................................................ 70

6.4 MAGNETIC FIELD DATA ...................................................................................................... 70

6.5 INTERRUPT STATUS REGISTER ........................................................................................... 73

6.6 POWER AND OPERATION MODES, SELF-TEST AND DATA OUTPUT RATE CONTROL REGISTERS .. 73

6.7 INTERRUPT AND AXIS ENABLE SETTINGS CONTROL REGISTERS ............................................. 75

6.8 NUMBER OF REPETITIONS CONTROL REGISTERS ................................................................. 77

7. DIGITAL INTERFACES ............................................................................................................ 79

7.1 SERIAL PERIPHERAL INTERFACE (SPI) ................................................................................ 80

7.2 INTER-INTEGRATED CIRCUIT (I²C) ...................................................................................... 84

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third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.

Note: Specifications within this document are subject to change without notice. Not intended for publication.

8. PIN-OUT AND CONNECTION DIAGRAM ............................................................................... 88

8.1 PIN-OUT ........................................................................................................................... 88

8.2 CONNECTION DIAGRAM 4-WIRE SPI ................................................................................... 90

8.3 CONNECTION DIAGRAM 3-WIRE SPI ................................................................................... 91

8.4 CONNECTION DIAGRAM I2C ................................................................................................ 92

9. PACKAGE ................................................................................................................................ 93

9.1 OUTLINE DIMENSIONS ....................................................................................................... 93

9.2 SENSING AXES ORIENTATION ............................................................................................. 94

9.3 ANDROID AXES ORIENTATION ............................................................................................. 95

9.4 LANDING PATTERN RECOMMENDATION ............................................................................... 97

9.5 MARKING .......................................................................................................................... 98

9.5.1 MASS PRODUCTION DEVICES ........................................................................................................ 98

9.5.2 ENGINEERING SAMPLES ................................................................................................................ 98

9.6 SOLDERING GUIDELINES .................................................................................................... 99

9.7 HANDLING INSTRUCTIONS ................................................................................................ 100

9.8 TAPE AND REEL SPECIFICATION ....................................................................................... 101

9.8.1 TAPE AND REEL DIMENSIONS....................................................................................................... 101

9.8.2 ORIENTATION WITHIN THE REEL ................................................................................................... 102

9.9 ENVIRONMENTAL SAFETY ................................................................................................ 103

9.9.1 HALOGEN CONTENT ................................................................................................................... 103

9.9.2 INTERNAL PACKAGE STRUCTURE ................................................................................................. 103

10. LEGAL DISCLAIMER........................................................................................................... 104

10.1 ENGINEERING SAMPLES................................................................................................. 104

10.2 PRODUCT USE .............................................................................................................. 104

10.3 APPLICATION EXAMPLES AND HINTS ............................................................................... 104

11. DOCUMENT HISTORY AND MODIFICATION ................................................................... 105

Datasheet

BMC050 Electronic Compass

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third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.

Note: Specifications within this document are subject to change without notice. Not intended for publication.

1. Specification

If not stated otherwise, the given values are over lifetime and full performance temperature and

voltage ranges, minimum/maximum values are ±3. The specifications are split into

accelerometer part and magnetometer part of BMC050.

1.1 Compass electrical specification

Table 1: Compass electrical parameter specification

COMPASS OPERATING CONDITIONS

Parameter

Symbol

Condition

Min

Typ

Max

Unit

Supply Voltage

Internal Domains

VDD

1.62

2.4

3.6

Supply Voltage

I/O Domain

VDDIO

1.2

1.8

3.6

Voltage Input

Low Level

VIL,a

SPI & I²C

0.3VDDIO

Voltage Input

High Level

VIH,a

SPI & I²C

0.7VDDIO

Voltage Output

Low Level

VOL,a

VDDIO = 1.62V

IOL = 3 mA, SPI & I²C

0.2VDDIO

VDDIO = 1.2V

IOL = 3 mA, SPI & I²C

0.23 VDDIO

Voltage Output

High Level

VOH,a

VDDIO = 1.62V

IOL = 2 mA, SPI & I²C

0.8VDDIO

VDDIO = 1.2V

IOL = 2 mA, SPI & I²C

0.62 VDDIO

1.2 Accelerometer specification

Table 2: Accelerometer parameter specification

ACCELEROMETER OPERATING CONDITIONS

Parameter

Symbol

Condition

Min

Typ

Max

Unit

Acceleration Range

gFS2g

Selectable

via serial digital interface

±2

gFS4g

±4

gFS8g

±8

gFS16g

±16

Supply Current in

Normal Mode

IDD,a

Nominal VDD supplies

TA=25°C, bw = 1kHz

139

µA

Supply Current in

Low-Power Mode

IDDlp,a

Nominal VDD supplies

TA=25°C, bw = 1kHz

sleep duration ≥ 25ms

µA

Supply Current in

Suspend Mode

IDDsm,a

Nominal VDD supplies

TA=25°C

0.5

µA

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Wake-Up Time

tw_up,a

from Low-Power Mode

or Suspend Mode,

bw = 1kHz

0.8

Start-Up Time

ts_up,a

POR, bw = 1kHz

Operating

Temperature

Same for accelerometer

and magnetometer

-40

+85

°C

ACCELEROMETER OUTPUT SIGNAL

Parameter

Symbol

Condition

Min

Typ

Max

Unit

Device Resolution

Dres,a

gFS2g

3.91

Sensitivity

S2g

gFS2g, TA=25°C

256

LSB/g

S4g

gFS4g, TA=25°C

128

LSB/g

S8g

gFS8g, TA=25°C

LSB/g

S16g

gFS16g, TA=25°C

LSB/g

Sensitivity

Temperature Drift

TCSa

gFS2g, -40°C ≤ TA ≤ +85°C

Nominal VDD supplies

±0.02

%/K

Zero-g Offset

Offa

gFS2g, TA=25°C

Nominal VDD supplies

±80

Zero-g Offset

Temperature Drift

TCOa

gFS2g, -40°C ≤ TA ≤ +85°C

Nominal VDD supplies

±1

mg/K

Bandwidth

bw8

1st order filter, selectable

via serial digital interface

bw16

bw31

bw63

bw125

125

bw250

250

bw500

500

bw1000

1000

Nonlinearity

NL,a

best fit straight line

±0.5

%FS

Output Noise

nrms,a

gFS2g, TA=25°C

Nominal VDD supplies

Normal mode

0.8

mg/Hz

Power Supply

Rejection Rate

PSRRa

TA=25°C

Nominal VDD supplies

mg/V

Temperature Sensor

Measurement Range

TA=25°C

Nominal VDD supplies

-40

+87.5

°C

Temperature Sensor

Slope

dTS

TA=25°C

Nominal VDD supplies

0.5

LSB/K

Temperature Sensor

Offset

OTS

TA=25°C

Nominal VDD supplies

±5

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ACCELEROMETER MECHANICAL CHARACTERISTICS

Parameter

Symbol

Condition

Min

Typ

Max

Unit

Cross Axis

Sensitivity

relative contribution

between any two of the

three axes

Alignment Error

EA,a

relative to package

outline

±0.5

1.3 Magnetometer specification

Table 3: Magnetometer parameter specification

MAGNETOMETER OPERATING CONDITIONS

Parameter

Symbol

Condition

Min

Typ

Max

Unit

Magnetic field

range

Brg,xy

TA=25°C, full active

measurement range

±1000

µT

Brg,z

2500

µT

Magnetometer

heading accuracy1

Amheading

30µT horizontal

geomagnetic field

component, TA=25°C

±2.5

degree

System heading

accuracy2

Asheading

30µT horizontal

geomagnetic field

component, TA=25°C

±3.5

degree

Supply Current in

Active Mode

(average)3

IDD,lp,m

Low power preset

Nominal VDD supplies

TA=25°C, ODR=10Hz

170

µA

IDD,rg,m

Regular preset

Nominal VDD supplies

TA=25°C, ODR=10Hz

0.5

IDD,eh,m

Enhanced regular preset

Nominal VDD supplies

TA=25°C, ODR=10Hz

0.8

IDD,ha,m

High accuracy preset

Nominal VDD supplies

TA=25°C, ODR=20Hz

4.9

Supply Current in

Suspend Mode

IDDsm,m

Nominal VDD/VDDIO

supplies, TA=25°C

µA

Peak supply current

in Active Mode

IDDpk,m

In measurement phase

Nominal VDD supplies

TA=25°C

Theoretical heading accuracy of the 3-axis magnetometer alone, assuming ideal

accelerometer and calibration with Bosch Sensortec eCompass software. Average value over

various device orientations (typical device usage).

Heading accuracy of the tilt-compensated 6-axis eCompass system, assuming calibration with

Bosch Sensortec eCompass software. Average value over various device orientations (typical

device usage).

For details on magnetometer current consumption calculation refer to chapter 4.3.2 and 4.3.3.

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Peak logic supply

current in active

mode

IDDIOpk,m

Only during

measurement phase

Nominal VDDIO supplies

TA=25°C

210

µA

POR time

tw_up,m

from OFF to suspend;

time starts when

VDD>1.5V and

VDDIO>1.1V

1.0

Start-Up Time

ts_up,m

from suspend to sleep

MAGNETOMETER OUTPUT SIGNAL

Parameter

Symbol

Condition

Min

Typ

Max

Unit

Device Resolution

Dres,m

TA=25°C (x,y,z)

0.3

µT

Sensitivity

After temperature

compensation

TA=25°C

Nominal VDD supplies

µT

sensor

output

per µT

applied

field

Sensitivity

Temperature Drift

TCSm

After temperature

compensation

-40°C ≤ TA ≤ +85°C

Nominal VDD supplies

±0.01

%/K

Zero-B offset

OFFm

TA=25°C

±10

µT

ODR (data output

rate), normal mode

odrlp

Low power preset

odrrg

Regular preset

odreh

Enhanced regular preset

odrha

High accuracy preset

ODR (data output

rate), forced mode

odrlp

Low power preset

>300

odrrg

Regular preset

100

odreh

Enhanced regular preset

odrha

High accuracy preset

Full-scale

Nonlinearity

NLm, FS

best fit straight line

%FS

Output Noise

nrms,lp,m,xy

Low power preset

x-, y-axis, TA=25°C

Nominal VDD supplies

1.0

µT

nrms,lp,m,z

Low power preset

z-axis, TA=25°C

Nominal VDD supplies

1.4

µT

nrms,rg,m

Regular preset

TA=25°C

Nominal VDD supplies

0.6

µT

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nrms,eh,m

Enhanced regular preset

TA=25°C

Nominal VDD supplies

0.5

µT

nrms,ha,m

High accuracy preset

TA=25°C

Nominal VDD supplies

0.3

µT

Power Supply

Rejection Rate

PSRRm

TA=25°C

Nominal VDD supplies

±0.5

µT/V

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2. Absolute maximum ratings

The absolute maximum ratings provided in Table 4 apply to both the accelerometer and

magnetometer part of BMC050.

Table 4: Absolute maximum ratings

Parameter

Condition

Min

Max

Unit

Voltage at Supply Pin

VDD Pin

-0.3

4.0

VDDIO Pin

-0.3

4.0

Voltage at any Logic Pad

Non-Supply Pin

-0.3

VDDIO +

0.3

Operating Temperature, TA

Active operation

-40

+85

°C

Passive Storage Temp. Range

≤ 65% rel. H.

-50

+150

°C

Mechanical Shock

Duration ≤ 200µs

10,000

Duration ≤ 1.0ms

2,000

Free fall onto hard

surfaces

1.8

ESD

HBM, at any Pin

CDM

500

Magnetic field

Any direction

> 7

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3. Block diagram

Figure 1 shows the basic building blocks of the BMC050:

Figure 1: Block diagram of BMC050

Gain &

Offset

Logic

Vref

C/U ADC

Regulator

NVM Osc

VDD GND

VDDIO

PS1

INT1

INT2

SDI

SDO

SCK

CSB1

Accelerometer

MEMS Accelerometer ASIC

X, Y

FlipCore

Drive &

Sense

Logic

Vref

Regulator

NVM Osc

VDD GND

VDDIO

PS2

INT3

DRDY

SDI

SDO

SCK

CSB2

FlipCores Magnetometer ASIC

Z Hall

element

Drive &

Sense

VDD

VDDIO

GND

PS1

INT1

INT2

SDI

SDO

SCK

CSB1

PS2

INT3

DRDY

CSB2

ADC

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4. Functional description

BMC050 is a SiP (system in package) integration of a triaxial accelerometer (Sensing element

and ASIC) and a triaxial geomagnetic sensor (Sensing element and ASIC) in one package. The

two ASICs act as two separate slave devices on the digital bus (with different I²C address in I²C

mode, or separate CSB lines in SPI mode, respectively), which allows an almost independent

operation of accelerometer and magnetometer parts in order to fit into a wide range of usage

scenarios.

Note: Default values for registers can be found in chapters 5 and 6.

4.1 Power management

The BMC050 has two distinct power supply pins which supply both the acceleration sensor part

and the magnetometer sensor part:

• VDD is the main power supply for all internal analog and digital functional blocks;

• VDDIO is a separate power supply pin, used for the supply of the digital interface as well as the

magnetic sensor‟s logic.

There are no limitations on the voltage levels of both pins relative to each other, as long as each

of them lies within its operating range. Furthermore, the device can be completely switched off

(VDD = 0V) while keeping the VDDIO supply on (VDDIO > 0V). To switch off the interface supply

(VDDIO = 0V) and keep the internal supply on (VDD > 0V) is safe only in normal mode of the

accelerometer part (magnetic sensor will switch to off mode automatically). If the accelerometer

part of the device is in low-power mode or suspend mode while VDDIO = 0V, there is a risk of

excess current consumption on the VDD supply (non-destructive).

It is absolutely prohibited to keep any interface at a logical high level when VDDIO is switched off.

Such a configuration will permanently damage the device (i.e. if VDDIO = 0  [SDI & SDO & SCK

& CSB1 & CSB2] ≠ high).

The device contains a power on reset (POR) generator for each of the sensor parts,

accelerometer part and magnetometer part. It resets the logic part and the register values of the

concerned ASIC after powering-on VDD and VDDIO. There is no limitation on the sequence of

switching on both supply voltages. In case the I²C interface is used, a direct electrical

connection between VDDIO supply and the PS pins (PS1 and PS2) is needed in order to ensure

reliable protocol selection (see chapter 4.2).

4.2 Protocol selection

The BMC050 acts as two separate slave devices (i.e. accelerometer part and magnetometer

part), on a digital interface (SPI or I²C) which is controlled by the external bus master (e.g. µC).

The master obtains measurement data and status information from the device through the

digital interface. In particular, the master can configure the interrupt controllers and read out the

interrupt status registers. Moreover, it can freely configure and use the interrupt pins (INT1,

INT2, INT3 and DRDY).

All pads are in input mode (no output driver active) during the start-up sequence until the

interface type is selected. The start-up sequence is run after power-up and after reset.

Datasheet

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Note: It is not possible to select mixed interfaces (I²C for accelerometer part and SPI for

magnetometer part or vice versa), because the digital interface uses shared pins.

Figure 2 illustrates the protocol selection:

Figure 2: Protocol selection

4.3 Power modes

The BMC050 features separately configurable power modes for the accelerometer and the

magnetometer part. The advantage is that different characteristics regarding optimum system

power saving of the two sensor types are exploited, and that the accelerometer part may also

be used alone in certain usage scenarios where no magnetic field data is required. In such an

example, the magnetometer part is able to suspend and save power during the time in which it

is not required.

In the following chapters, power modes for both accelerometer and magnetometer part are

described.

4.3.1 Accelerometer power modes

The BMC050 accelerometer part has four different power modes (see Figure 4). Besides normal

mode, which represents the fully operational state of the device, there are two special energy

saving modes: low-power mode and suspend mode.

Reset (both accelerometer

and magnetometer)

Protocol

select

I²C operation SPI operation

One or more

interrupts can be

configured via I²C

One or more

interrupts can be

configured via SPI

PS1=PS2=GND

PS1=PS2=VDDIO

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The possible transitions between the power modes are illustrated in Figure 3:

Low-Power

Mode

Suspend

Mode

Normal

Mode

Power off

Figure 3: Accelerometer power mode transition diagram

Power off mode is enabled when VDD and/or VDDIO are unpowered. In this state, the

accelerometer does not operate. Power on reset is performed after both supply voltages have

risen above their detection thresholds.

In normal mode, all parts of the electronic circuit are held powered-up and data acquisition is

performed continuously.

In contrast to this, in suspend mode the whole analog part, oscillators included, is powered

down. No data acquisition is performed, the only supported operations are reading registers

(latest acceleration data are kept) and writing to the (0x11) suspend bit or (0x14) softreset

In low-power mode, the device is periodically switching between a sleep phase and a wake-up

phase. The wake-up phase essentially corresponds to operation in normal mode with complete

power-up of the circuitry. During the sleep phase the analog part except the oscillators is

powered down. Low-power mode is entered (left) by writing “1” (“0”) to the (0x11) lowpower_en

bit.

During the wake-up phase the number of samples required by any enabled interrupt is

processed. If an interrupt is detected, the device stays in the wake-up phase as long as the

interrupt condition endures (non-latched interrupt), or until the latch time expires (temporary

interrupt), or until the interrupt is reset (latched interrupt). If no interrupt is detected, the device

enters the sleep phase.

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The duration of the sleep phase is set by the (0x11) sleep_dur bits as shown in the following

table:

Table 5: Sleep phase duration settings

(0x11)

sleep_dur

Sleep Phase Duration

tsleepa

0000b

0.5ms

0001b

0.5ms

0010b

0.5ms

0011b

0.5ms

0100b

0.5ms

0101b

0.5ms

0110b

1ms

0111b

2ms

1000b

4ms

1001b

6ms

1010b

10ms

1011b

25ms

1100b

50ms

1101b

100ms

1110b

500ms

1111b

The current consumption of the BMC050 accelerometer part can be calculated according to this

formula:

aactiveasleep

aDDaactiveaDDsmasleep

aDDlp tt

ItIt

,,,,

,





In this formula, the subfix “a” indicates that the current and time variables refer to the

accelerometer part of BMC050, to distinguish from the magnetometer part.

When making an estimation about the length of the wake-up phase tactive,a, the wake-up time,

tw_up,a, has to be considered. Therefore, tactive,a = tu,at + tw_up,a, where tu,at is given in Table 9.

During the wake-up phase all analog modules are held powered-up, while during the sleep

phase most analog modules are powered down. As a consequence, a wake-up time of less

than 1ms (typ. value 0.8ms) is needed to settle the analog modules in order to get reliable

acceleration data.

Table 6 gives an overview of the resulting average supply currents for the different sleep phase

durations and a selected bandwidth of 1000Hz, assuming no interrupt is active and thus only

one sample per wake-up phase is taken:

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Table 6: Accelerometer part average current consumption in low-power mode

Sleep phase duration

Average current consumption

0.5ms

100.5 µA

1ms

78.8 µA

2ms

55.0 µA

4ms

34.5 µA

6ms

25.2 µA

10ms

16.4 µA

25ms

7.4 µA

50ms

4.0 µA

100ms

2.3 µA

500ms

0.9 µA

0.7 µA

4.3.2 Magnetometer power modes

The BMC050 magnetometer part has four power modes:

Power off mode

In Power off mode, VDD and/or VDDIO are unpowered. The magnetometer part does not

operate in this mode. When only one of VDD or VDDIO is supplied, the magnetic sensor will still be

in Power off mode. Power on reset is performed after both VDD and VDDIO have risen above their

detection thresholds.

Suspend mode

Suspend mode is the default power mode of BMC050 magnetometer part after the chip is

powered. When VDD and VDDIO are turned on the POR (power on reset) circuits operate and

the device‟s registers are initialized. After POR becomes inactive, a start up sequence is

executed. In this sequence NVM content is downloaded to shadow registers located in the

device core. After the start up sequence the device is put in the Suspend mode. In this mode

only registers supplied directly by VDDIO which store I2C slave device address, power control

bit information and some others can be accessed by the user. No other registers can be

accessed in Suspend mode. All registers lose their content, except the control register (0x4B).

In particular, in this mode a Chip ID read (register 0x40) returns “0x00h” (I²C) or high-Z (SPI).

Sleep mode

The user puts device from suspend into Sleep mode by setting the Power bit to “1”, or from

active modes (normal or forced) by setting OpMode bits to “11”. In this state the user has full

access to the device registers. In particular, the Chip ID can be read. Setting the power control

bit to “0” (register 0x4B bit0) will bring the device back into Suspend mode. From the Sleep

mode the user can put the device back into Suspend mode or into Active mode.

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Active mode

The device can switch into Active mode from Sleep mode by setting OpMode bits (register

0x4C). In active mode the magnetic field measurements are performed. In active mode, all

registers are accessible.

In active mode, two operation modes can be distinguished:

 Normal mode: selected channels are periodically measured according to settings set in

user registers. After measurements are completed, output data is put into data registers

and the device waits for the next measurement period, which is set by programmed

output data rate (ODR). From normal mode, the user can return to sleep mode by setting

OpMode to “11” or by performing a soft reset (see chapter 6.6). Suspend mode can be

entered by setting power control bit to “0”.

 Forced mode (single measurement): When set by the host, the selected channels are

measured according to settings programmed in user registers. After measurements are

completed, output data is put into data registers, OpMode register value returns to “11”

and the device returns to sleep mode. The forced mode is useful to achieve

synchronized operation between host microcontroller and BMC050. Also, different data

output rates from the ones selectable in normal mode can be achieved using forced

mode.

Figure 4: Magnetometer power mode transition diagram

In Active Mode and normal operation, in principle any desired balance between output noise

and active time (hence power consumption) can be adjusted by the repetition settings for x/y-

axis and z-axis and the output data rate ODR. The average power consumption depends on the

ratio of high current phase time (during data acquisition) and low current phase time (between

data acquisitions). Hence, the more repetitions are acquired to generate one magnetic field data

point, the longer the active time ratio in one sample phase, and the higher the average current.

Thanks to longer internal averaging, the noise level of the output data reduces with increasing

number of repetitions.

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By using forced mode, it is possible to trigger new measurements at any rate. The user can

therefore trigger measurements in a shorter interval than it takes for a measurement cycle to

complete. If a measurement cycle is not allowed to complete, the resulting data will not be

written into the data registers. To prevent this, the manually triggered measurement intervals

must not be shorter than the active measurement time which is a function of the selected

number of repetitions. The maximum selectable read-out frequency in forced mode can be

calculated as follows:

µsnZµsnXYµs

fODR 980500145 1

max, 



Hereby nXY is the number of repetitions on X/Y-axis (not the register value) and nZ the number

of repetitions on Z-axis (not the register value) (see description of XY_REP and Z_REP

registers in chapter 6).

Although the repetition numbers for X/Y and Z axis and the ODR can be adjusted independently

and in a wide range, there are four recommended presets (High accuracy preset, Enhanced

regular preset, Regular preset, Low power preset) which reflect the most common usage

scenarios, i.e. required output accuracy at a given current consumption, of the BMC050

magnetometer part.

The three presets consist of the below register configurations, which are automatically set by

the BMC050 API or driver provided by Bosch Sensortec when a preset is selected. Table 7

shows the recommended presets and the resulting magnetic field output noise and

magnetometer part current consumption:

Table 7: Magnetometer presets in Active operation and normal mode:

Preset

X/Y rep

Z rep

ODR

ODRmax

(forced

mode)

RMS

Noise

x/y/z

Average

current

consumption

Low power

preset

10 Hz

>300 Hz

1.0/1.0/1.4

µT

170 µA

Regular preset

10 Hz

100 Hz

0.6/0.6/0.6

µT

0.5 mA

Enhanced

regular preset

10 Hz

60 Hz

0.5/0.5/0.5

µT

0.8 mA

High accuracy

preset

20 Hz

0.3/0.3/0.3

µT

4.9 mA

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4.3.3 BMC050 overall power consumption

Below, Table 8 shows the overall current consumption of BMC050 (sum of accelerometer and

magnetometer part) in typical scenarios such as a tilt-compensated electronic compass

application.

Table 8: BMC050 overall current consumption in typical usage scenarios:

Compass

preset

Acc. Active /

sleep

interval

Mag.

DOR

Acc. BW

/ DOR

Mag. avg.

current

Acc. avg.

current

Total

average

current

Low power

preset

8 / 50 ms

10 Hz

62.5 / 17

170 µA

20 µA

190 µA

Regular

preset

16 / 50 ms

10 Hz

31 / 15

0.5 mA

35 µA

0.54 mA

Enhanced

regular preset

16 / 50 ms

10 Hz

31 / 15

0.8 mA

35 µA

0.84 mA

High accuracy

preset

16 /25 ms

20 Hz

31 / 24

4.9 mA

55 µA

5.0 mA

4.4 Sensor data

4.4.1 Acceleration data

The width of acceleration data is 10 bits given in two´s complement representation. The 10 bits

for each axis are split into an MSB upper part (one byte containing bits 9 to 2) and an LSB lower

part (one byte containing bits 1 and 0 of acceleration and a (0x02, 0x04, 0x06) new_data flag).

Reading the acceleration data registers shall always start with the LSB part. The content of an

MSB register is updated by reading the corresponding LSB register (shadowing procedure). The

shadowing procedure can be disabled (enabled) by writing “1” (“0”) to the bit shadow_dis. With

disabled shadowing, the content of both MSB and LSB registers is updated by a new value

immediately. Unused bits of the LSB registers are fixed to 0. The (0x02, 0x04, 0x06) new_data

flag of each LSB register is set if the data registers are updated, it is reset if either the

corresponding MSB or LSB part is read.

Two different streams of acceleration data are available, unfiltered and filtered. The unfiltered

data is sampled with 2kHz. The sampling rate of the filtered data depends on the selected filter

bandwidth; it is twice the bandwidth. Which kind of data is stored in the acceleration data

registers depends on bit (0x13) data_high_bw. If (0x13) data_high_bw is “0” (“1”), then filtered

(unfiltered) data is stored in the registers. Both data streams are separately offset-compensated.

Both kinds of data can be processed by the interrupt controller.

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The bandwidth of filtered acceleration data is determined by setting the (0x10) bw bit as follows:

Table 9: Bandwidth configuration

Bandwidth

Update Time

tut

00xxx

01000

7.81Hz

64ms

01001

15.63Hz

32ms

01010

31.25Hz

16ms

01011

62.5Hz

8ms

01100

125Hz

4ms

01101

250Hz

2ms

01110

500Hz

1ms

01111

1000Hz

0.5ms

1xxxx

*) Note: Settings 00xxx result in a bandwidth of 7.81 Hz; settings 1xxxx result in a bandwidth of

1000 Hz. It is recommended to actively use the range from “01000b” to “01111b” only in order to

be compatible with future products.

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The BMC050‟s accelerometer part supports four different acceleration measurement ranges.

A measurement range is selected by setting the (0x0F) range bits as follows:

Table 10: Range selection

Range

Acceleration

measurement

range

Resolution

0011

±2g

3.91mg/LSB

0101

±4g

7.81mg/LSB

1000

±8g

15.62mg/LSB

1100

±16g

31.25mg/LSB

others

reserved

4.4.2 Temperature data

The width of temperature data is 8 bits given in two´s complement representation. Temperature

values are available in the (0x08) temp register.

The slope of the temperature sensor is 0.5K/LSB, its center temperature is 24°C [(0x08) temp =

0x00]. Therefore, the typical temperature measurement range is -40°C up to 87.5°C.

4.4.3 Magnetic field data

The representation of magnetic field data is different between X/Y-axis and Z-axis. The width of

X- and Y-axis magnetic field data is 13 bits each and stored in two‟s complement.

DATAX_LSB (0x42) contains 5-bit LSB part [4:0] of the 13 bit output data of the X-channel.

DATAX_MSB (0x43) contains 8-bit MSB part [12:5] of the 13 bit output data of the X-channel.

DATAY_LSB (0x44) contains 5-bit LSB part [4:0] of the 13 bit output data of the Y-channel.

DATAY_MSB (0x45) contains 8-bit MSB part [12:5] of the 13 bit output data of the Y-channel.

The width of the Z-axis magnetic field data is 15 bit word stored in two‟s complement.

DATAZ_LSB (0x46) contains 7-bit LSB part [6:0] of the 15 bit output data of the Z-channel.

DATAZ_MSB (0x47) contains 8-bit MSB part [14:7] of the 15 bit output data of the Z-channel.

For all axes, temperature compensation on the host is used to get ideally matching sensitivity

over the full temperature range. The temperature compensation is based on a resistance

measurement of the hall sensor plate. The resistance value is represented by a 14 bit unsigned

output word.

RHALL_LSB (0x48) contains 6-bit LSB part [5:0] of the 14 bit output data of the RHALL-

channel.

RHALL_MSB (0x49) contains 8-bit MSB part [13:6] of the 14 bit output data of the RHALL-

channel.

All signed register values are in two´s complement representation. Bits which are marked

“reserved” can have different values or can in some cases not be read at all (read will return

0x00 in I²C mode and high-Z in SPI mode).

Data register readout and shadowing is implemented as follows:

After all enabled axes have been measured, complete data packages consisting of DATAX,

DATAY, DATAZ and RHALL are updated at once in the data registers. This way, it is prevented

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that a following axis is updated while the first axis is still being read (axis mix-up) or that MSB

part of an axis is updated while LSB part is being read.

While reading from any data register, data register update is blocked. Instead, incoming new

data is written into shadow registers which will be written to data registers after the previous

read sequence is completed (i.e. upon stop condition in I²C mode, or CSB going high in SPI

mode, respectively). Hence, it is recommended to read out at all data at once (0x42 to 0x49 or

0x4A if status bits are also required) with a burst read.

Single bytes or axes can be read out, while in this case it is not assured that adjacent registers

are not updated during readout sequence.

The “Data ready status” bit (register 0x48 bit0) is set “1” when the data registers have been

updated but the data was not yet read out over digital interface. Data ready is cleared (set “0”)

directly after completed read out of any of the data registers and subsequent stop condition

(I²C) or lifting of CSB (SPI).

In addition, when enabled the “Data overrun” bit (register 0x4A bit7) turns “1” whenever data

registers are updated internally, but the old data was not yet read out over digital interface (i.e.

data ready bit was still high). The “Data overrun” bit is cleared when the interrupt status register

0x4A is read out. This function needs to be enabled separately by setting the “Data overrun En”

bit (register 0x4D bit7)).

Note: Please also see chapter 6 for detailed register descriptions.

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4.4.4 Magnetic field data temperature compensation

The raw register values DATAX, DATAY, DATAZ and RHALL are read out from the host

processor using the BMC050 API/driver which is provided by Bosch Sensortec. The API/driver

performs an off-chip temperature compensation and outputs x/y/z magnetic field data in

16 LSB/µT to the upper application layer:

Figure 5: Calculation flow of magnetic field data from raw BMC050 register data

The API/driver performs all calculations using highly optimized fixed-point C-code arithmetic.

For platforms that do not support C code, a floating-point formula is available as well.

BMC050

sensor

Hardware level

Software

driver level

BMC050

API / driver

(provided by

Bosch Sensortec)

Application

Software

application level

Magnetometer raw register data

(DATAX, DATAY, DATAZ, RHALL)

Temperature compensated

magnetic field data x/y/z in

(signed short int, 16 LSB/µT)

Config

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4.5 Self-test

4.5.1 Accelerometer self-test

This feature permits to check the BMC050‟s accelerometer part functionality by applying

electrostatic forces to the sensor core instead of external accelerations. By actually deflecting

the seismic mass, the entire signal path of the sensor can be tested. Activating the self-test

results in a static offset of the acceleration data; any external acceleration or gravitational force

applied to the sensor during active self-test will be observed in the output as a superposition of

both acceleration and self-test signal.

The self-test is activated individually for each axis by writing the proper value to the (0x32)

self_test_axis bits (“01b” for x-axis, “10b” for y-axis, “11b” for z-axis, “00b” to deactivate self-

test). It is possible to control the direction of the deflection through bit (0x32) self_test_sign. The

excitation occurs in positive (negative) direction if (0x32) self_test_sign = “0” (“1”).

In order to ensure a proper interpretation of the self-test signal it is recommended to perform the

self-test for both (positive and negative) directions and then to calculate the difference of the

resulting acceleration values. Table 11 shows the minimum differences for each axis. The

actually measured signal differences can be significantly larger.

Table 11: Self-test difference values

x-axis signal

y-axis signal

z-axis signal

resulting

minimum

difference signal

+0.8 g

+0.4 g

It is recommended to perform a reset of the device after self-test. If the reset cannot be

performed, the following sequence must be kept to prevent unwanted interrupt generation:

disable interrupts, change parameters of interrupts, wait for at least 600 s, enable desired

interrupts.

4.5.2 Magnetometer self-test

BMC050 supports two self-tests modes for the magnetometer part: Normal self-test and

advanced self-test.

Normal self test

During normal self-test, the following verifications are performed:

 FlipCore signal path is verified by generating signals on-chip. These are processed

through the signal path and the measurement result is compared to known thresholds.

 FlipCore (X and Y) bondwires to ASIC are checked for connectivity

 FlipCore (X and Y) bondwires and MEMS are checked for shorts

 Hall sensor connectivity is checked for open and shorted connections

 Hall sensor signal path and hall sensor element offset are checked for overflow.

To perform a self test, the sensor must first be put into sleep mode (OpMode = “11”). Self-test

mode is then entered by setting the bit “Self test” (register 0x4C bit0) to “1”. After performing self

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test, this bit is set back to “0”. When self-test is successful, the corresponding self-test result bits

are set to “1” (“X-Self-Test” register 0x42 bit0, “Y-Self-Test” register 0x44 bit0, “Z-Self-Test”

Advanced self test

Advanced self test performs a verification of the Z channel signal path functionality and

sensitivity. An on-chip coil wound around the hall sensor can be driven in both directions with a

calibrated current to generate a positive or negative field of around 100 µT.

Advanced self test is an option that is active in parallel to the other operation modes. The only

difference is that during the active measurement phase, the coil current is enabled. The

recommended usage of advanced self test is the following:

1. Set sleep mode

2. Disable X, Y axis

3. Set Z repetitions to desired level

4. Enable positive advanced self test current

5. Set forced mode, readout Z and R channel after measurement is finished

6. Enable negative advanced self test current

7. Set forced mode, readout Z and R channel after measurement is finished

8. Disable advanced self test current (this must be done manually)

9. Calculate difference between the two compensated field values. This difference should

be around 200 µT with some margins.

10. Perform a soft reset of manually restore desired settings

Please refer to the corresponding application note for the exact thresholds to evaluate

advanced self-test.

Below table describes how the advanced self-test is controlled:

Table 12: Magnetometer advanced self-test control

(0x4C)

Adv.ST <1:0>

Configuration

00b

Normal operation

(no self-test), default

01b

Reserved, do not use

10b

Negative on-chip magnetic

field generation

11b

Positive on-chip magnetic

field generation

The BMC050 API/driver provided by Bosch Sensortec provides a comfortable way to perform

both self-tests and to directly obtain the result without further calculations. It is recommended to

use this as a reference.

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4.6 Accelerometer offset compensation

Offsets in measured acceleration signals can have several causes but they are always

unwanted and disturbing in many cases. Therefore, the BMC050 offers an advanced set of four

digital offset compensation methods which are closely matched to each other. These are slow,

fast, and manual compensation, and inline calibration.

The compensation is performed for unfiltered and filtered acceleration data independently. It is

done by adding a compensation value to the acceleration data coming from the ADC. The result

of this computation is saturated if necessary to prevent any overflow errors (the smallest or

biggest possible value is set, depending on the sign). However, the public registers used to read

and write compensation values have only a width of 8 bits.

An overview of the offset compensation principle is given in Figure 6:

Figure 6: Principle of offset compensation

The meaning of both public and internal registers is the same for all acceleration measurement

ranges. Therefore, with measurement ranges other than ±2g, one or more lower significant bits

of the internal registers are lost when added to an acceleration value, or are set to zero when

the internal compensation value is computed. If a compensation value is too small or too big to

fit into the corresponding internal register, it is saturated to prevent an overflow error.

In a similar way the conversion of the internal register value to the public register value (10bit to

8bit) uses saturation.

bit_11

bit_12

bit_10

bit_9

bit_8

bit_7

bit_6

bit_5

bit_4

bit_3

bit_2

bit_1

bit_0

sign (msb)

62.5mg

31.3mg

15.6mg

7.8mg (lsb)

125mg

250mg

500mg

sign (msb)

62.5mg

31.3mg

15.6mg

7.8mg

3.9mg (lsb)

125mg

250mg

500mg

8bit – 10bit

conversion

sign (msb)

62.5mg

31.3mg

15.6mg

7.8mg

125mg

250mg

500mg

2gsign (msb)

62.5mg

31.3mg

15.6mg

7.8mg

3.9mg

125mg

250mg

500mg

sign (msb)

62.5mg

31.3mg

15.6mg

125mg

250mg

500mg

sign (msb)

62.5mg

31.3mg

125mg

250mg

500mg

acceleration data

range: ±2g ±16g

±4g ±8g

offset_filt_full_x/y/z

offset_unfilt_x/y/z

(10bit)

internal register

offset_filt_x/y/z

offset_unfilt_x/y/z

(8bit)

public register

add to

compute compensation value

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Summarized, in dependence to the measurement range which has been set, the compensation

value, which has been written into the public register will correct the data output according to

Figure 6.

e.g. ±2g range:

public register = 00000001b  add to acceleration data = ±7.8mg = +2LSB

public register = 00000010b  add to acceleration data = +15.6mg = +4LSB

public register = 00000101b  add to acceleration data = +39.1mg = +10LSB

The public registers are image registers of EEPROM registers. With each image update (see

chapter 4.7 for details) the contents of the non-volatile EEPROM registers are written to the

public registers. At any time the public register can be over-written by the user. After changing

the contents of the public registers by either an image update or manually, all 8bit values are

widened to 10bit values and stored in the corresponding internal registers. In the opposite

direction, if the value of an internal register changes due to the computation performed by a

compensation algorithm, it is converted to an 8bit value and stored in the public register.

For slow and fast offset compensation, the compensation target can be chosen by setting the

bits (0x37) offset_target_x, (0x37) offset_target_y, and (0x37) offset_target_z according to

Table 13:

Table 13: Offset target settings

(0x37)

offset_target_x/y/z

Target value

00b

01b

+1g

10b

-1g

11b

By writing “1” to the (0x36) offset_reset bit, all offset compensation registers are reset to zero.

4.6.1 Slow compensation

Slow compensation is a quasi-continuous process which regulates the acceleration value of

each axis towards the target value by comparing the current value with the target and adding or

subtracting a fixed value depending on the comparison.

The algorithm in detail: If an acceleration value is larger (smaller) than the target value (0x37)

offset_target_x/y/z for a number of samples (given by the parameter Offset Period, see Table

14), the internal offset compensation value (0x38, 0x39, 0x3A) offset_filt_x/y/z or (0x3B, 0x03C,

0x3D) offset_unfilt_x/y/z is decremented (incremented) by 4 LSB.

The public registers (0x38, 0x39, 0x3A) offset_filt_x/y/z and (0x3B, 0x03C, 0x3D)

offset_unfilt_x/y/z are not used for the computations but they are updated with the contents of

the internal registers (using saturation if necessary) and can be read by the user.

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The compensation period offset_period is set by the (0x37) cut_off bit as represented in Table

14:

Table 14: Compensation period settings

(0x37)

cut_off

Offset

Period

The slow compensation can be enabled (disabled) for each axis independently by setting the

bits (0x36) hp_x_en, hp_y_en, hp_z_en to “1” (“0”), respectively.

Slow compensation should not be used in combination with low-power mode. In low-power

mode the conditions (availability of necessary data) for proper function of slow compensation

are not fulfilled.

4.6.2 Fast compensation

Fast compensation is a one-shot process by which the compensation value is set in such a way

that when added to the raw acceleration, the resulting acceleration value of each axis equals

the target value.

The algorithm in detail: An average of 16 consecutive acceleration values is computed and the

difference between target value and computed value is written to (0x38, 0x39, 0x3A)

offset_filt_x/y/z or (0x3B, 0x3C, 0x3D) offset_unfilt_x/y/z The public registers (0x38, 0x39, 0x3A)

offset_filt_x/y/z and (0x3B, 0x3C, 0x3D) offset_unfilt_x/y/z are updated with the contents of the

internal registers (using saturation if necessary) and can be read by the user.

Fast compensation is triggered for each axis individually by setting the (0x36) cal_trigger bits as

shown in Table 15:

Table 15: Fast compensation axis selection

(0x36)

cal_trigger

Selected Axis

00b

none

01b

10b

11b

The register (0x36) cal_trigger keeps its non-zero value while the fast compensation procedure

is running. Slow compensation is blocked as long as fast compensation endures. Bit (0x36)

cal_rdy is “0” when (0x36) cal_trigger is not “00”.

Fast compensation should not be used in combination with low-power mode. In low-power

mode the conditions (availability of necessary data) for proper function of fast compensation are

not fulfilled.

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4.6.3 Manual compensation

As explained above, the contents of the public compensation registers (0x38, 0x39, 0x3A)

offset_filt_x/y/z and (0x3B, 0x3C, 0x3D) offset_unfilt_x/y/z can be set manually via the digital

interface. It is recommended to write into these registers immediately after a new data interrupt

in order not to disturb running offset computations.

Writing to the offset compensation registers is not allowed if slow compensation is enabled or if

the fast compensation procedure is running.

4.6.4 Inline calibration

For a given application, it is often desirable to calibrate the offset once and to store the

compensation values permanently. This can be achieved by using one of the aforementioned

offset compensation methods to determine the proper compensation values and then storing

these values permanently in the non-volatile memory (EEPROM). See chapter 4.7 for details of

the storing procedure.

Each time the device is reset, the compensation values are loaded from the non-volatile

memory into the image registers and used for offset compensation until they are possibly

overwritten using one of the other compensation methods.

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4.7 Non-volatile memory

4.7.1 Accelerometer non-volatile memory

The memory of the accelerometer part of BMC050 consists of three different kinds of registers:

hard-wired, volatile, and non-volatile. Non-volatile memory is implemented as EEPROM. Part of

it can be both read and written by the user. Access to non-volatile memory is only possible

through (volatile) image registers.

Altogether, there are eight registers (bytes) of EEPROM which are accessible by the customer.

The address range of the image registers range from 0x38 to 0x3F. While the addresses up to

0x3D are used for offset compensation (see 4.6 Offset Compensation), addresses 0x3E and

0x3F are general purpose registers not linked to any sensor-specific functionality.

The content of the EEPROM is loaded to the image registers after a reset (either POR or

softreset) or after a user request which is performed by writing “1” to bit (0x33) nvm_load. As

long as the image update is not yet complete, bit (0x33) nvm_load is “1”, otherwise it is “0”.

The image registers can be read and written like any other register.

Writing to the EEPROM is a three-step procedure:

1. Write the new contents to the image registers.

2. Write “1” to bit (0x33) nvm_prog_mode in order to unlock the EEPROM.

3. Write “1” to bit (0x33) nvm_prog_trig and keep “1” in bit (0x33) nvm_prog_mode in order

to trigger the write process.

Writing to the EEPROM always renews the entire EEPROM contents. It is possible to check the

write status by reading bit (0x33) nvm_rdy. While (0x33) nvm_rdy = “0”, the write process is still

enduring; if (0x33) nvm_rdy = “1”, then writing is completed. As long as the write process is

ongoing, no power mode change and no image update is allowed. It is forbidden to write to the

EEPROM while the image update is running, in low-power mode, and in suspend mode.

4.7.2 Magnetometer non-volatile memory

Some of the memory of the BMC050 magnetometer is non-volatile memory (NVM). This NVM is

pre-programmed in Bosch Sensortec fabrication line and can not be modified afterwards. It

contains trimming data which are required for sensor operation and sensor data compensation,

thus it is read out by the BMC050 API/driver during initialization.

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4.8 Accelerometer interrupt controller

Seven accelerometer based interrupt engines are integrated in the accelerometer part of

BMC050. Each interrupt can be independently enabled and configured. If the condition of an

enabled interrupt is fulfilled, the corresponding status bit is set to “1” and the selected interrupt

pin is activated. There are two interrupt pins for the accelerometer part, INT1 and INT2;

interrupts can be freely mapped to any of these pins. The pin state is a logic ´or´ combination of

all mapped interrupts.

The interrupt status registers are updated together with writing new data into the acceleration

data registers. If an interrupt is disabled, all active status bits and pins are immediately reset.

All time constants are based upon the typical frequency of the internal oscillator. This is

reflected by the bandwidths (bw) as specified in Table 9.

4.8.1 General features

An interrupt is cleared depending on the selected interrupt mode, which is common to all

interrupts. There are three different interrupt modes for the accelerometer part: non-latched,

latched, and temporary. The mode is selected by the (0x21) latch_int bits according to Table 16.

Table 16: Accelerometer interrupt mode selection

(0x21)

latch_int

Interrupt mode

0000b

non-latched

0001b

temporary, 250ms

0010b

temporary, 500ms

0011b

temporary, 1s

0100b

temporary, 2s

0101b

temporary, 4s

0110b

temporary, 8s

0111b

latched

1000b

non-latched

1001b

temporary, 500µs

1010b

temporary, 500µs

1011b

temporary, 1ms

1100b

temporary, 12.5ms

1101b

temporary, 25ms

1110b

temporary, 50ms

1111b

latched

An interrupt is generated if its activation condition is met. It can not be cleared as long as the

activation condition is fulfilled. In the non-latched mode the interrupt status bit and the selected

pin (the contribution to the ´or´ condition for INT1 and/or INT2) are cleared as soon as the

activation condition is no more valid. Exceptions to this behaviour are the new data, orientation,

and flat interrupts, which are automatically reset after a fixed time.

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In the latched mode an asserted interrupt status and the selected pin are cleared by writing “1”

to bit (0x21) reset_int. If the activation condition still holds when it is cleared, the interrupt status

is asserted again with the next change of the acceleration registers.

In the temporary mode an asserted interrupt and selected pin are cleared after a defined period

of time. The behaviour of the different interrupt modes is shown graphically in Figure 7:

Figure 7: Interrupt modes

Several interrupt engines can use either unfiltered or filtered acceleration data as their input. For

these interrupts, the source can be selected with the respective (0x1E) int_src_... bits, in details

these are (0x1E) int_src_data, (0x1E) int_src_tap, (0x1E) int_src_slope, (0x1E ) int_src_high,

and (0x1E) int_src_low. Setting the respective bits to “0” (“1”) selects filtered (unfiltered) data as

input. For the other interrupts, orientation recognition and flat detection, such a selection is not

possible. They always use filtered input data.

It is strongly recommended to set interrupt parameters prior to enabling the interrupt. Changing

parameters of an already enabled interrupt may cause unwanted interrupt generation and

generation of a false interrupt history. A safe way to change parameters of an enabled interrupt

is to keep the following sequence: disable the desired interrupt, change parameters, wait for at

least 600 s, enable the desired interrupt.

4.8.2 Mapping (inttype to INT Pin#)

The mapping of interrupts to the interrupt pins #05 or #06 is done by registers (0x19) to (0x1B).

Setting (0x19) int1_”inttyp” to “1” (“0”) maps (unmaps) “inttyp” to pin #5 (INT1), correspondingly

setting (0x1B) int2_”inttyp” to “1” (“0”) maps (unmaps) “inttyp” to pin #6 (INT2).

Note: “inttyp” to be replaced with the precise notation, given in the memory map in chapter 5.

Example: For flat interrupt (int1_flat): Setting (0x19) int1_flat to “1” maps int1_flat to pin #5

(INT1).

4.8.3 Electrical behavior (INT pin# to open-drive or push-pull)

Both interrupt pins can be configured to show desired electrical behaviour. The ´active´ level of

each pin is determined by the (0x20) int1_lvl and (0x20) int2_lvl bits.

internal signal from

interrupt engine

interrupt output

non-latched

temporary

latched

latch period

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If (0x20) int1_lvl = “1” (“0”) / (0x20) int2_lvl = “1” (“0”), then pin #05 (INT1) / pin #06 (INT2) is

active “1” (“0”). In addition to that, also the electric type of the interrupt pins can be selected. By

setting bits (0x20) int1_od / (0x20) int2_od to “0”, the interrupt pin output type becomes open-

drive, by setting the configuration bits to “1”, the output type becomes push-pull.

Remark: The states of both INT pins are not defined during the first 2 ms after power-up.

4.8.4 New data interrupt

This interrupt serves for synchronous reading of acceleration data. It is generated after storing a

new value of z-axis acceleration data in the data register. The interrupt is cleared automatically

when the next cycle of data acquisition starts. The interrupt status is “0” for at least 50µs.

The interrupt mode of the new data interrupt is fixed to non-latched.

It is enabled (disabled) by writing “1” (“0”) to bit (0x17) data_en. The interrupt status is stored in

bit (0x0A) data_int.

4.8.5 Any-motion (slope) detection

Any-motion detection uses the slope between successive acceleration signals to detect

changes in motion. An interrupt is generated when the slope (absolute value of acceleration

difference) exceeds a preset threshold. It is cleared as soon as the slope falls below the

threshold. The principle is clarified in Figure 8.

Figure 8: Principle of any-motion detection

slope_th

INT

slope

acceleration

acc(t0)

acc(t0−1/(2*bw))

slope(t0)=acc(t0)−acc(t0−1/(2*bw))

time

slope_dur

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The threshold is set with the value of register (0x28) slope_th. 1 LSB of (0x28) slope_th

corresponds to 1 LSB of acceleration data. Therefore, an increment of (0x28) slope_th is 3.91

mg in 2g-range (7.81 mg in 4g-range, 15.6 mg in 8g-range and 31.3 mg in 16g-range). And the

maximum value is 996 mg in 2g-range (1.99g in 4g-range, 3.98g in 8g-range and 7.97g in 16g-

range).

The time difference between the successive acceleration signals depends on the selected

bandwidth and equates to 1/(2*bandwidth) (Δt=1/(2*bw)). In order to suppress failure signals,

the interrupt is only generated (cleared) if a certain number N of consecutive slope data points

is larger (smaller) than the slope threshold given by (0x28) slope_th. This number is set by the

(0x27) slope_dur bits. It is N = (0x27) slope_dur + 1 for (0x27).

Example: (0x27) slope_dur = 00b, …, 11b = 1decimal, …, 4decimal

4.8.5.1 Enabling (disabling) for each axis

Any-motion detection can be enabled (disabled) for each axis separately by writing “1” (“0”) to

bits (0x16) slope_en_x, (0x16) slope_en_y, (0x16) slope_en_z. The criteria for any-motion

detection are fulfilled and the slope interrupt is generated if the slope of any of the enabled axes

exceeds the threshold (0x28) slope_th for [(0x27) slope_dur +1] consecutive times. As soon as

the slopes of all enabled axes fall or stay below this threshold for [(0x27) slope_dur +1]

consecutive times the interrupt is cleared unless interrupt signal is latched.

4.8.5.2 Axis and sign information of any motion interrupt

The interrupt status is stored in bit (0x09) slope_int. The any-motion interrupt supplies additional

information about the detected slope. The axis which triggered the interrupt is given by that one

of bits (0x0B) slope_first_x, (0x0B) slope_first_y, (0x0B) slope_first_z that contains a “1”. The

sign of the triggering slope is held in bit (0x0B) slope_sign. If (0x0B) slope_sign = “0” (“1”), the

sign is positive (negative).

4.8.5.3 Serial interface and dedicated wake-up mode

When serial interface is active, any-motion detection logic is enabled if any of the axis specific

(0x16) slope_en_... register bits are set. To disable the any-motion interrupt, clear all the axis

specific (0x16) slope_en_... bits.

4.8.6 Tap sensing

Tap sensing has a functional similarity with a common laptop touch-pad or clicking keys of a

computer mouse. A tap event is detected if a pre-defined slope of the acceleration of at least

one axis is exceeded. Two different tap events are distinguished: A „single tap‟ is a single event

within a certain time, followed by a certain quiet time. A „double tap‟ consists of a first such

event followed by a second event within a defined time frame.

Only one of the tap interrupts can be enabled at the same time. Single tap interrupt is enabled

(disabled) by writing “1” (“0”) to bit (0x16) s_tap_en. Double tap interrupt is enabled (disabled)

by writing “1” (“0”) to bit (0x16) d_tap_en. If one tries to enable both interrupts by writing “1” to

(0x16) s_tap_en and (0x16) d_tap_en, then only (0x16) d_tap_en keeps the value “1” and the

double tap interrupt is enabled.

The status of the single tap interrupt is stored in bit (0x09) s_tap_int, the status of the double tap

interrupt is stored in bit (0x09) d_tap_int.

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The slope threshold for detecting a tap event is set by bits (0x2B) tap_th. The meaning of

(0x2B) tap_th depends on the range setting. 1 LSB of (0x2B) tap_th corresponds to a slope of

62.5mg in 2g-range, 125mg in 4g-range, 250mg in 8g-range, and 500mg in 16g-range.

In Figure 9 the meaning of the different timing parameters is visualized:

Figure 9: Timing of tap detection

The parameters (0x2A) tap_shock and (0x2A) tap_quiet apply to both single tap and double tap

detection, while (0x2A) tap_dur applies to double tap detection only. Within the duration of

(0x2A) tap_shock any slope exceeding (0x2B) tap_th after the first event is ignored. Contrary to

this, within the duration of (0x2A) tap_quiet no slope exceeding (0x2B) tap_th must occur,

otherwise the first event will be cancelled.

4.8.6.1 Single tap detection

A single tap is detected and the single tap interrupt is generated after the combined durations of

(0x2A) tap_shock and (0x2A) tap_quiet, if the corresponding slope conditions are fulfilled. The

interrupt is cleared after a delay of 12.5 ms.

tap_shock tap_quiet tap_dur

tap_shock tap_quiet

time

12.5 ms

single tap detection

double tap detection

slope

time

12.5 ms

time

1st tap 2nd tap

tap_th

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4.8.6.2 Double tap detection

A double tap is detected and the double tap interrupt is generated if an event fulfilling the

conditions for a single tap occurs within the set duration in (0x2A) tap_dur after the completion

of the first tap event. The interrupt is cleared after a delay of 12.5 ms.

4.8.6.3 Selecting the timing of tap detection

For each of parameters (0x2A) tap_shock and (0x2A) tap_quiet two values are selectable. By

writing “0” (“1”) to bit (0x2A) tap_shock the duration of (0x2A) tap_shock is set to 50 ms (75 ms).

By writing “0” (“1”) to bit (0x2A) tap_quiet the duration of (0x2A) tap_quiet is set to 30 ms (20

ms).

The length of (0x2A) tap_dur can be selected by setting the (0x2A) tap_dur bits according to

Table 17:

Table 17: Selection of tap_dur

(0x2A)

tap_dur

length of tap_dur

000b

50 ms

001b

100 ms

010b

150 ms

011b

200 ms

100b

250 ms

101b

375 ms

110b

500 ms

111b

700 ms

4.8.6.4 Axis and sign information of tap sensing

The sign of the slope of the first tap which triggered the interrupt is stored in bit (0x0B) tap_sign

(“0” means positive sign, “1” means negative sign). The value of this bit persists after clearing

the interrupt.

The axis which triggered the interrupt is indicated by bits (0x0B) tap_first_x, (0x0B) tap_first_y,

and (0x0B) tap_first_z.

The bit corresponding to the triggering axis contains a “1” while the other bits hold a “0”. These

bits are cleared together with clearing the interrupt status.

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4.8.6.5 Tap sensing in low power mode

In low-power mode, a limited number of samples is processed after wake-up to decide whether

an interrupt condition is fulfilled. The number of samples is selected by bits (0x2B) tap_samp

according to Table 18.

Table 18: Meaning of (0x2B) tap_samp

(0x2B)

tap_samp

Number of

Samples

00b

01b

10b

11b

4.8.7 Orientation recognition

The orientation recognition feature informs on an orientation change of the sensor with respect

to the gravitational field vector „g‟. The measured acceleration vector components with respect

to the gravitational field are defined as shown in Figure 10.

Figure 10: Definition of vector components

Therefore, the magnitudes of the acceleration vectors are calculated as follows:

acc_x = 1g∙sin∙cos

acc_y = −1g∙sin∙sin

acc_z = 1g∙cos

→ acc_y/acc_x = −tan

Depending on the magnitudes of the acceleration vectors the orientation of the device in the

space is determined and stored in the three (0x0C) orient bits. These bits may not be reset in

the sleep phase of low-power mode. There are three orientation calculation modes with different

thresholds for switching between different orientations: symmetrical, high-asymmetrical, and

low-asymmetrical. The mode is selected by setting the (0x2C) orient_mode bits as given in

Table 19.

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Table 19: Orientation mode settings

(0x2C)

orient_mode

Orientation Mode

00b

symmetrical

01b

high-asymmetrical

10b

low-asymmetrical

11b

symmetrical

For each orientation mode the (0x0C) orient bits have a different meaning as shown in Table 20

to Table 22:

Table 20: Meaning of the (0x0C) orient bits in symmetrical mode

(0x0C)

orient

Name

Angle

Condition

x00

portrait upright

315° <  < 45°

|acc_y| < |acc_x| - „hyst‟

and acc_x - „hyst‟’ ≥ 0

x01

portrait upside down

135° <  < 225°

|acc_y| < |acc_x| - „hyst‟

and acc_x + „hyst‟ < 0

x10

landscape left

45° <  < 135°

|acc_y| ≥ |acc_x| + „hyst‟

and acc_y < 0

x11

landscape right

225° <  < 315°

|acc_y| ≥ |acc_x| + „hyst‟

and acc_y ≥ 0

Table 21: Meaning of the (0x0C) orient bits in high-asymmetrical mode

(0x0C)

orient

Name

Angle

Condition

x00

portrait upright

297° <  < 63°

|acc_y| < 2·|acc_x| - „hyst‟

and acc_x - „hyst‟ ≥ 0

x01

portrait upside down

117° <  < 243°

|acc_y| < 2·|acc_x| - „hyst‟

and acc_x + „hyst‟ < 0

x10

landscape left

63° <  < 117°

|acc_y| ≥ 2·|acc_x| + „hyst‟

and acc_y < 0

x11

landscape right

243° <  < 297°

|acc_y| ≥ 2·|acc_x| + „hyst‟

and acc_y ≥ 0

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Table 22: Meaning of the (0x0C) orient bits in low-asymmetrical mode

(0x0C)

orient

Name

Angle

Condition

x00

portrait upright

333° <  < 27°

|acc_y| < 0.5·|acc_x| - „hyst‟

and acc_x - „hyst‟ ≥ 0

x01

portrait upside down

153° <  < 207°

|acc_y| < 0.5·|acc_x| - „hyst‟

and acc_x + „hyst‟ < 0

x10

landscape left

27° <  < 153°

|acc_y| ≥ 0.5·|acc_x| + „hyst‟

and acc_y < 0

x11

landscape right

207° <  < 333°

|acc_y| ≥ 0.5·|acc_x| + „hyst‟

and acc_y ≥ 0

In the preceding tables, the parameter „hyst‟ stands for a hysteresis, which can be selected by

setting the (0x0C) orient_hyst bits. 1 LSB of (0x0C) orient_hyst always corresponds to 62.5 mg,

in any g-range (i.e. increment is independent from g-range setting). It is important to note that by

using a hysteresis ≠ 0 the actual switching angles become different from the angles given in the

tables since there is an overlap between the different orientations.

The most significant bit of the (0x0C) orient bits (which is displayed as an “x” in the above given

tables) contains information about the direction of the z-axis. It is set to “0” (“1”) if acc_z ≥ 0

(acc_z < 0).

Figure 11 shows the typical switching conditions between the four different orientations for the

symmetrical mode (i.e. without hysteresis):

-2

-1.5

-1

-0.5

0.5

1.5

0 45 90 135 180 225 270 315 360

phi

acc_y/acc_x

acc_x/sin(theta)

acc_y/sin(theta)

portrait upright landscape left portrait upside

down

landscape right portrait upright

-2

-1.5

-1

-0.5

0.5

1.5

0 45 90 135 180 225 270 315 360

acc_y/acc_x

acc_x/sin(theta)

acc_y/sin(theta)

portrait upright landscape left portrait upside

down

landscape right portrait upright

Figure 11: Typical orientation switching conditions w/o hysteresis

The orientation interrupt is enabled (disabled) by writing “1” (“0”) to bit (0x16) orient_en. The

interrupt is generated if the value of (0x0C) orient has changed. It is automatically cleared after

one stable period of the (0x0C) orient value. The interrupt status is stored in the (0x09)

orient_int bit.

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If temporary or latched interrupt mode is used, after the generation of the interrupt the changed

(0x0C) orient value is kept fixed as long as the interrupt persists (e. g. until the latch time

expires or the interrupt is reset). After clearing the interrupt, the (0x0C) orient is only updated

with the next following value change (i.e. with the next occurring interrupt). In order to ensure

the continuous availability of up-to-date orientation data it is therefore optimal to use the non-

latched interrupt. It is strongly advised against using latched interrupt mode or temporary

interrupt mode with latch times above 50 ms for orient recognition.

4.8.7.1 Orientation blocking

The change of the (0x0C) orient value and – as a consequence – the generation of the interrupt

can be blocked according to conditions selected by setting the value of the (0x2C)

orient_blocking bits as described by Table 23.

Table 23: Blocking conditions for orientation recognition

(0x2C)

orient_blocking

Conditions

00b

no blocking

01b

theta blocking

10b

theta blocking

acceleration slope in any axis > 0.2 g

11b

value of orient is not stable for at least 100 ms

theta blocking

acceleration slope in any axis > 0.4 g

The theta blocking is defined by the following inequality:

tan thetablocking





The parameter blocking_theta of the above given equation stands for the contents of the (0x2D)

orient_theta bits. Hereby it is possible to define a blocking angle between 0° and 44.8°. The

internal blocking algorithm saturates the acceleration values before further processing. As a

consequence, the blocking angles are strictly valid only for a device at rest; they can be different

if the device is moved.

Example:

To get a maximum blocking angle of 19° the parameter blocking_theta is determined in the

following way: (8 * tan(19°) )² = 7.588, therefore, blocking_value = 8dec = 001000b has to be

chosen.

In order to avoid unwanted generation of the orientation interrupt in a nearly flat position (z ~ 0,

sign change due to small movements or noise), a hysteresis of 0.2 g is implemented for the z-

axis, i. e. a after a sign change the interrupt is only generated after |z| > 0.2 g.

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4.8.8 Flat detection

The flat detection feature gives information about the orientation of the devices´ z-axis relative

to the g-vector, i. e. it recognizes whether the device is in a flat position or not.

The condition for the device to be in the flat position is

tan thetaparameter





Like blocking_theta, used with orientation recognition, the parameter_theta stands for a user-

defined setting. In this case the content of the (0x2E) flat_theta bits. The possible flat angles

also range from 0° to 44.8°. To ensure proper operation, parameter_theta has to be less than or

equal to blocking_theta.

The flat interrupt is enabled (disabled) by writing “1” (“0”) to bit (0x16) flat_en. The flat interrupt

is generated if the flat value has changed and the new value is stable for at least the time given

by the (0x2F) flat_hold_time bits. The flat value is stored in the (0x0C) flat bit if the interrupt is

enabled. This value is “1” if the device is in the flat position, it is “0” otherwise. The content of

the (0x0C) flat bit is changed only if the interrupt is generated. The interrupt is automatically

cleared after one sample period. Its status is stored in the (0x09) flat_int bit.

If temporary or latched interrupt mode is used, after the generation of the interrupt the changed

(0x0C) flat value is kept fixed as long as the interrupt persists (e. g. until the latch time expires

or the interrupt is reset). After clearing the interrupt, the (0x0C) flat value is only updated with

the next following value change (i.e. with the next occurring interrupt).

The meaning of the (0x2F) flat_hold_time bits can be seen from Table 24.

Table 24: Meaning of flat_hold_time

(0x2F)

flat_hold_time

Time

00b

01b

512 ms

10b

1024 ms

11b

2048 ms

4.8.9 Low-g interrupt

This interrupt is based on the comparison of acceleration data against a low-g threshold, which

is most useful for free-fall detection.

The interrupt is enabled (disabled) by writing “1” (“0”) to the (0x17) low_en bit. There are two

modes available, „single‟ mode and „sum‟ mode. In „single‟ mode, the acceleration of each axis

is compared with the threshold; in „sum‟ mode, the sum of absolute values of all accelerations

contents of the (0x24) low_mode bit: “0” means „single‟ mode, “1” means „sum‟ mode.

The low-g threshold is set through the (0x23) low_th register. 1 LSB of (0x23) low_th always

corresponds to an acceleration of 7.81 mg (i.e. increment is independent from g-range setting).

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A hysteresis can be selected by setting the (0x24) low_hy bits. 1 LSB of (0x24) low_hy always

corresponds to an acceleration difference of 125 mg in any g-range (as well, increment is

independent from g-range setting).

The low-g interrupt is generated if the absolute values of the acceleration of all axes (´and´

relation, in case of single mode) or their sum (in case of sum mode) are lower than the threshold

for at least the time defined by the (0x22) low_dur register. The interrupt is reset if the absolute

value of the acceleration of at least one axis (´or´ relation, in case of single mode) or the sum of

absolute values (in case of sum mode) is higher than the threshold plus the hysteresis for at

least one data acquisition. In bit (0x09) low_int the interrupt status is stored.

The relation between the content of (0x22) low_dur and the actual delay of the interrupt

generation is: delay [ms] = [(0x22) low_dur + 1] • 2 ms. Therefore, possible delay times range

from 2 ms to 512 ms.

4.8.10 High-g interrupt

This interrupt is based on the comparison of acceleration data against a high-g threshold for the

detection of shock or other high-acceleration events.

The high-g interrupt is enabled (disabled) per axis by writing “1” (“0”) to bits (0x17) high_en_x,

(0x17) high_en_y, and (0x17) high_en_z, respectively. The high-g threshold is set through the

(0x26) high_th register. The meaning of an LSB of (0x26) high_th depends on the selected g-

range: it corresponds to 7.81 mg in 2g-range, 15.63 mg in 4g-range, 31.25 mg in 8g-range, and

62.5 mg in 16g-range (i.e. increment depends from g-range setting).

A hysteresis can be selected by setting the (0x24) high_hy bits. Analogously to (0x26) high_th,

the meaning of an LSB of (0x24) high_hy is g-range dependent: it corresponds to an

acceleration difference of 125 mg in 2g-range, 250 mg in 4g-range, 500 mg in 8g-range, and

1000mg in 16g-range (as well, increment depends from g-range setting).

The high-g interrupt is generated if the absolute value of the acceleration of at least one of the

enabled axes (´or´ relation) is higher than the threshold for at least the time defined by the

(0x25) high_dur register. The interrupt is reset if the absolute value of the acceleration of all

enabled axes (´and´ relation) is lower than the threshold minus the hysteresis for at least the

time defined by the (0x25) high_dur register. In bit (0x09) high_int the interrupt status is stored.

The relation between the content of (0x25) high_dur and the actual delay of the interrupt

generation is delay [ms] = [(0x22) low_dur + 1] • 2 ms. Therefore, possible delay times range

from 2 ms to 512 ms.

4.8.10.1 Axis and sign information of high-g interrupt

The axis which triggered the interrupt is indicated by bits (0x0C) high_first_x, (0x0C)

high_first_y, and (0x0C) high_first_z. The bit corresponding to the triggering axis contains a “1”

while the other bits hold a “0”. These bits are cleared together with clearing the interrupt status.

The sign of the triggering acceleration is stored in bit (0x0C) high_sign. If (0x0C) high_sign = “0”

(“1”), the sign is positive (negative).

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4.9 Magnetometer interrupt controller

Four magnetometer based interrupt engines are integrated in the magnetometer part of

BMC050: Low-Threshold, High-Threshold, Overflow and Data Ready (DRDY). Each interrupt

can be enabled independently.

When enabled, an interrupt sets the corresponding status bit in the interrupt status register

(0x4A) when its condition is satisfied.

When the “Interrupt Pin Enable” bit (register 0x4E bit6) is set, any occurring activated interrupts

are flagged on the BMC050‟s INT3 output pin. By default, the interrupt pin is disabled (high-Z

status).

Low-Threshold, High-Threshold and Overflow interrupts are mapped to the INT3 pin when

enabled, Data Ready (DRDY) interrupt is mapped to the DRDY pin of BMC050 when enabled.

For High- and Low-Threshold interrupts each axis X/Y/Z can be enabled separately for interrupt

detection in the registers “High Int Z en”, “High Int Y en”, “High Int X en”, “Low Int Z en”, “Low Int

Y En” and “Low Int X En” in register 0x4D bit5-bit0. Overflow interrupt is shared for X, Y and Z

axis.

When the “Data Ready Pin En” bit (register 0x4E bit7) is set, the Data Ready (DRDY) interrupt

event is flagged on the BMC050‟s DRDY output pin (by default the “Data Ready Pin En” bit is

not set and DRDY pin is in high-Z state).

The interrupt status registers are updated together with writing new data into the magnetic field

data registers. The status bits for Low-/High-Threshold interrupts are located in register 0x4A,

the Data Ready (DRDY) status flag is located at register 0x48 bit0.

If an interrupt is disabled, all active status bits and pins are reset after the next measurement

was performed.

4.9.1 General features

An interrupt is cleared depending on the selected interrupt mode, which is common to all

interrupts. There are two different interrupt modes: non-latched and latched. All interrupts

(except Data Ready) can be latched or non-latched. Data Ready (DRDY) is always cleared after

readout of data registers ends.

A non-latched interrupt will be cleared on a new measurement when the interrupt condition is

not valid anymore, whereas a latched interrupt will stay high until the interrupts status register

(0x4A) is read out. After reading the interrupt status, both the interrupt status bits and the

interrupt pin are reset. The mode is selected by the “Interrupt latch” bit (register 0x4A bit1),

where the default setting of “1” means latched. Figure 12 shows the difference between the

modes for the example Low-Threshold interrupt.

INT3 and DRDY pin polarity can be changed by the “Interrupt polarity” bit (register 0x4E bit0)

and “DR polarity” (register 0x4E bit2), from the default high active (“1”) to low active (“0”).

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Figure 12: Interrupt latched and non-latched mode

4.9.2 Electrical behavior of magnetic interrupt pins

Both interrupt pins INT3 and DRDY are push/pull when the corresponding interrupt pin enable

bit is set, and are floating (High-Z) when the corresponding interrupt pin enable bit is disabled

(default).

4.9.3 Data ready / DRDY interrupt

This interrupt serves for synchronous reading of magnetometer data. It is generated after

storing a new set of values (DATAX, DATAY, DATAZ, RHALL) in the data registers:

Figure 13: Data acquisition and DRDY operation (DRDY in “high active” polarity)

The interrupt mode of the Data Ready (DRDY) interrupt is fixed to non-latched.

It is enabled (disabled) by writing “1” (“0”) to “Data Ready pin En” in register 0x4E bit7.

Low threshold

measurements

INT3 pin (non-latched)

INT3 pin (latched)

Readings of interrupt status register (0x4A)

Active measurement time

Preset time Measurement Data processing

Data write into

output registers

DRDY =’1’

Measurement phase start Data readout

Measurement Data processing

Inactive time

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DRDY pin polarity can be changed by the “DR polarity” bit (register 0x4E bit2), from the default

high active (“1”) to low active (“0”).

4.9.4 Low-threshold interrupt

When the data registers‟ (DATAX, DATAY and DATAZ) values drop below the threshold level

defined by the “Low Threshold register (0x4F), the corresponding interrupt status bits for those

axes are set (“Low Int X”, “Low Int Y” and “Low Int Z” in register 0x4A). This is done for each

axis independently. Please note that the X and Y axis value for overflow is -4096. However, no

interrupt is generated on these values. See chapter 4.9.6 for more information on overflow.

Hereby, one bit in “Low Threshold” corresponds to roughly 6µT (not exactly, as the raw

magnetic field values DATAX, DATAY and DATAZ are not temperature compensated).

The Low-threshold interrupt is issued on INT3 pin when one or more values of the data registers

DATAX, DATAY and DATAZ drop below the threshold level defined by the “Low Threshold”

generation:

Result = (DATAX < “Low Threshold” x 16) AND “Low Int X en” is “0” OR

(DATAY < “Low Threshold” x 16) AND “Low Int Y en” is “0” OR

(DATAZ < “Low Threshold” x 16) AND “Low Int Z en” is “0”

Note: Threshold interrupt enable bits (“Low INT [XYZ] en”) are active low and “1” (disabled) by

default.

Figure 14: Low-threshold interrupt function

Low threshold

measurements

INT3 pin (non-latched)

INT3 pin (latched) Read interrupt status

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4.9.5 High-threshold interrupt

When the data registers‟ (DATAX, DATAY and DATAZ) values exceed the threshold level

defined by the “High Threshold register (0x50), the corresponding interrupt status bits for those

axes are set (“High Int X”, “High Int Y” and “High Int Z” in register 0x4A). This is done for each

axis independently.

Hereby, one bit in “High Threshold” corresponds to roughly 6µT (not exactly, as the raw

magnetic field values DATAX, DATAY and DATAZ are not temperature compensated).

The High-threshold interrupt is issued on INT3 pin when one or more values of the data

registers DATAX, DATAY and DATAZ exceed the threshold level defined by the “High

Threshold” register (0x50), and when the axis where the threshold was exceeded is enabled for

interrupt generation:

Result = (DATAX > “High Threshold” x 16) AND “High Int X en” is “0” OR

(DATAY > “High Threshold” x 16) AND “High Int Y en” is “0” OR

(DATAZ > “High Threshold” x 16) AND “High Int Z en” is “0”

Note: Threshold interrupt enable bits (“High INT [XYZ] en”) are active low and “1” (disabled) by

default.

Figure 15: High-threshold interrupt function

4.9.6 Overflow

When a measurement axis had an overflow, the corresponding data register is saturated to the

most negative value. For X and Y axis, the data register is set to the value -4096. For the Z axis,

the data register is set to the value -16384.

The “Overflow” flag (register 0x4A bit6) indicates that the measured magnetic field raw data of

one or more axes exceeded maximum range of the device. The overflow condition can be

flagged on the INT3 pin by setting the bit “overflow int enable” (register 0x4D bit6, active high,

default value “0”). The channel on which overflow occurred can be determined by assessing the

DATAX/Y/Z registers.

High threshold

measurements

INT3 pin (non-latched)

INT3 pin (latched) Read interrupt status

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5. Accelerometer register description

5.1 General remarks

The entire communication with the device is performed by reading from and writing to registers.

Registers have a width of 8 bits; they are mapped to a common space of 64 addresses from

(0x00) up to (0x3F). Within the used range there are several registers which are either

completely or partially marked as „reserved‟. Any reserved bit is ignored when it is written and

no specific value is guaranteed when read. It is recommended not to use registers at all which

are completely marked as „reserved‟. Further-more it is recommended to mask out (logical and

with zero) reserved bits of registers which are partially marked as reserved.

Registers with addresses from (0x00) up to (0x0E) are read-only. Any attempt to write to these

registers is ignored. There are bits within some registers that connected with an action to be

done and, therefore, are intended for write-only access, e. g. (0x21) reset_int or the entire

(0x14) softreset register. Such bits always give “0” when read.

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5.2 Register map

5.3 Chip ID

Table 25: Chip identification number, register (0x00)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

0x3F 0x00

0x3E 0x00

0x3D 0x00

0x3C 0x00

0x3B 0x00

0x3A 0x00

0x39 0x00

0x38 0x00

0x37 0x00 reserved cut_off

0x36 0x00 offset_reset cal_rdy reserved hp_z_en hp_y_en hp_x_en

0x35 0x00

0x34 0x00 i2c_wdt_en i2c_wdt_sel spi3

0x33 0x04 nvm_load nvm_rdy nvm_prog_trig nvm_prog_mode

0x32 0x70 self_test_sign

0x31 0x00

0x30 0x00

0x2F 0x10

0x2E 0x08

0x2D 0x08

0x2C 0x18 reserved

0x2B 0x0A reserved

0x2A 0x04

tap_quiet tap_shock

0x29 0x00

0x28 0x14

0x27 0x00

0x26 0xC0

0x25 0x0F

0x24 0x81 low_mode

0x23 0x30

0x22 0x09

0x21 0x00 reset_int

0x20 0x05 int2_od int2_lvl int1_od int1_lvl

0x1F 0x00

0x1E 0x00 int_src_data int_src_tap reserved int_src_slope int_src_high int_src_low

0x1D 0x00

0x1C 0x00

0x1B 0x00 int2_flat int2_orient int2_s_tap int2_d_tap reserved int2_slope int2_high int2_low

0x1A 0x00 int2_data int1_data

0x19 0x00 int1_flat int1_orient int1_s_tap int1_d_tap reserved int1_slope int1_high int1_low

0x18 0x00

0x17 0x00 data_en low_en high_en_z high_en_y high_en_x

0x16 0x00 flat_en orient_en s_tap_en d_tap_en reserved slope_en_z slope_en_y slope_en_x

0x15 0x00

0x14 0x00

0x13 0x00 data_high_bw shadow_dis

0x12 0x00

0x11 0x00 suspend lowpower_en reserved reserved

0x10 0x1F

0x0F 0x03

0x0E 0x00

0x0D 0x00

0x0C 0x00 flat high_sign high_first_z high_first_y high_first_x

0x0B 0x00 tap_sign tap_first_z tap_first_y tap_first_x slope_sign slope_first_z slope_first_y slope_first_x

0x0A 0x00 data_int reserved

0x09 0x00 flat_int orient_int s_tap_int d_tap_int reserved slope_int high_int low_int

0x08 0x00

0x07 0x00

0x06 0x00 new_data_z

0x05 0x00

0x04 0x00 new_data_y

0x03 0x00

0x02 0x00 new_data_x

0x01 0x21

0x00 0x03

w/r

write only

read only

reserved

acc_z_lsb<1:0>

acc_x_lsb<1:0>

acc_y_lsb<1:0>

acc_x_msb<9:2>

acc_y_msb<9:2>

orient[2:0]

reserved

sleep_dur<3:0>

bw<4:0>

low_th<7:0>

softreset

reserved

low_dur<7:0>

reserved

cal_trigger<1:0>

offset_filt_x<7:0>

offset_target_z<1:0>

offset_filt_y<7:0>

offset_filt_z<7:0>

offset_target_y<1:0>

offset_target_x<1:0>

offset_unfilt_z<7:0>

offset_unfilt_y<7:0>

orient_theta<5:0>

reserved

offset_unfilt_x<7:0>

reserved

self_test_axis

acc_z_msb<9:2>

range<3:0>

reserved

tap_th<4:0>

flat_theta<5:0>

flat_hold_time<1:0>

reserved

orient_blocking<1:0>

orient_mode<1:0>

reserved

tap_samp<1:0>

reserved

high_th<7:0>

reserved

tap_dur<2:0>

reserved

orient_hyst<2:0>

Chip ID

high_dur<7:0>

slope_th<7:0>

low_hy<1:0>

slope_dur<1:0>

high_hy<1:0>

temp<7:0>

reserved

latch_int<3:0>

reserved

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5.4 Acceleration data

x-axis.

Table 26: LSB part of x-axis acceleration, register (0x02)

(0x02) Bit

Name

Description

Bit 7

acc_x_lsb <1>

Bit 1 of x-axis acceleration data

Bit 6

acc_x_lsb <0>

Bit 0 of x-axis acceleration data = x LSB

Bit 5

(fixed to 0)

Bit 4

(fixed to 0)

Bit 3

(fixed to 0)

Bit 2

(fixed to 0)

Bit 1

(fixed to 0)

Bit 0

new_data_x

New data flag of x-axis

Table 27: MSB part of x-axis acceleration, register (0x03)

(0x03)

Bit

Name

Description

Bit 7

acc_x_msb <9>

Bit 9 of x-axis acceleration data = x MSB

Bit 6

acc_x_msb <8>

Bit 8 of x-axis acceleration data

Bit 5

acc_x_msb <7>

Bit 7 of x-axis acceleration data

Bit 4

acc_x_msb <6>

Bit 6 of x-axis acceleration data

Bit 3

acc_x_msb <5>

Bit 5 of x-axis acceleration data

Bit 2

acc_x_msb <4>

Bit 4 of x-axis acceleration data

Bit 1

acc_x_msb <3>

Bit 3 of x-axis acceleration data

Bit 0

acc_x_msb <2>

Bit 2 of x-axis acceleration data

y-axis.

Table 28: LSB part of y-axis acceleration, register (0x04)

(0x04)

Bit

Name

Description

Bit 7

acc_y_lsb <1>

Bit 1 of y-axis acceleration data

Bit 6

acc_y_lsb <0>

Bit 0 of y-axis acceleration data = y LSB

Bit 5

(fixed to 0)

Bit 4

(fixed to 0)

Bit 3

(fixed to 0)

Bit 2

(fixed to 0)

Bit 1

(fixed to 0)

Bit 0

new_data_y

New data flag of y-axis

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Table 29: MSB part of y-axis acceleration, register (0x05)

(0x05)

Bit

Name

Description

Bit 7

acc_y_msb <9>

Bit 9 of y-axis acceleration data = y MSB

Bit 6

acc_y_msb <8>

Bit 8 of y-axis acceleration data

Bit 5

acc_y_msb <7>

Bit 7 of y-axis acceleration data

Bit 4

acc_y_msb <6>

Bit 6 of y-axis acceleration data

Bit 3

acc_y_msb <5>

Bit 5 of y-axis acceleration data

Bit 2

acc_y_msb <4>

Bit 4 of y-axis acceleration data

Bit 1

acc_y_msb <3>

Bit 3 of y-axis acceleration data

Bit 0

acc_y_msb <2>

Bit 2 of y-axis acceleration data

Table 30: LSB part of y-axis acceleration, register (0x06)

(0x06)

Bit

Name

Description

Bit 7

acc_z_lsb <1>

Bit 1 of z-axis acceleration data

Bit 6

acc_z_lsb <0>

Bit 0 of z-axis acceleration data = z LSB

Bit 5

(fixed to 0)

Bit 4

(fixed to 0)

Bit 3

(fixed to 0)

Bit 2

(fixed to 0)

Bit 1

(fixed to 0)

Bit 0

new_data_z

New data flag of z-axis

Table 31: MSB part of z-axis acceleration, register (0x07)

(0x07)

Bit

Name

Description

Bit 7

acc_z_msb <9>

Bit 9 of z-axis acceleration data = z MSB

Bit 6

acc_z_msb <8>

Bit 8 of z-axis acceleration data

Bit 5

acc_z_msb <7>

Bit 7 of z-axis acceleration data

Bit 4

acc_z_msb <6>

Bit 6 of z-axis acceleration data

Bit 3

acc_z_msb <5>

Bit 5 of z-axis acceleration data

Bit 2

acc_z_msb <4>

Bit 4 of z-axis acceleration data

Bit 1

acc_z_msb <3>

Bit 3 of z-axis acceleration data

Bit 0

acc_z_msb <2>

Bit 2 of z-axis acceleration data

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5.5 Temperature data

temperature = 24 °C  i.e. (0x08) temp = 00000000b

1 LSB increment of temperature sensor is 0.5 °C (0.9 °F).

Table 32: Temperature data, register (0x08)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Temp

<7>

Temp

<6>

Temp

<5>

Temp

<4>

Temp

<3>

Temp

<2>

Temp

<1>

Temp

<0>

5.6 Status registers

Table 33: Interrupt status, register (0x09)

(0x09)

Bit

Name

Description

Bit 7

flat_int

Flat interrupt status

Bit 6

orient_int

Orientation interrupt status

Bit 5

s_tap_int

Single tap interrupt status

Bit 4

d_tap_int

Double tap interrupt status

Bit 3

- reserved -

reserved

Bit 2

slope_int

Slope interrupt status

Bit 1

high_int

High-g interrupt status

Bit 0

low_int

Low-g interrupt status

Table 34: New data status, register (0x0A)

(0x0A) Bit

Name

Description

Bit 7

data_int

New data interrupt status

Bit 6

- reserved -

reserved

Bit 5

- reserved -

reserved

Bit 4

- reserved -

reserved

Bit 3

- reserved -

reserved

Bit 2

- reserved -

reserved

Bit 1

- reserved -

reserved

Bit 0

- reserved -

reserved

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interrupts. Here tap interrupt comprises both single and double tap interrupt.

Table 35: Tap and slope interrupts status, register (0x0B)

(0x0B) Bit

Name

Description

Bit 7

tap_sign

Sign of 1st tap that triggered the interrupt (“0”=positive,

“1”=negative)

Bit 6

tap_first_z

“1” indicates that z-axis is triggering axis of tap interrupt

Bit 5

tap_first_y

“1” indicates that y-axis is triggering axis of tap interrupt

Bit 4

tap_first_x

“1” indicates that x-axis is triggering axis of tap interrupt

Bit 3

slope_sign

Sign of slope that triggered the interrupt (“0”=positive,

“1”=negative)

Bit 2

slope_first_z

“1” indicates that z-axis is triggering axis of slope

interrupt

Bit 1

slope_first_y

“1” indicates that y-axis is triggering axis of slope

interrupt

Bit 0

slope_first_x

“1” indicates that x-axis is triggering axis of slope

interrupt

information for the high-g interrupt. Registers (0x0D) and (0x0E) are reserved.

Table 36: Flat and orientation Status, register (0x0C)

(0x0C) Bit

Name

Description

Bit 7

flat

flat detection (“1” if flat condition is fulfilled, “0”

otherwise)

Bit 6

orient <2>

orientation value of z-axis (“0“ if upward looking, “1“ if

downward looking)

Bit 5

orient <1>

orientation value of x-y plane (“00”=portrait upright,

“01”=portrait upside-down, “10”=landscape left,

“11”=landscape right)

Bit 4

orient <0>

Bit 3

high_sign

Sign of slope that triggered the interrupt (“0”=positive,

“1”=negative)

Bit 2

high_first_z

“1” indicates that z-axis is triggering axis of high-g

interrupt

Bit 1

high_first_y

“1” indicates that y-axis is triggering axis of high-g

interrupt

Bit 0

high_first_x

“1” indicates that x-axis is triggering axis of high-g

interrupt

Registers (0x0D) and (0x0E) are reserved.

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5.7 g-range selection

“0011b” (selects ±2g range), “0101b” (selects ±4g range), “1000b” (selects ±8g range), “1100b”

(selects ±16g range). All other settings are irregular; if such a setting is used, ±2g range is

selected. Default value of (0x0F) range (after reset) is “0011b”.

Table 37: g-range, register (0x0F)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

reserve

range

<3>

range

<2>

range

<1>

range

<0>

5.8 Bandwidths

for (0x10) bw are “00xxxb” (bandwidth = 7.81 Hz), “01000b” (bandwidth = 7.81 Hz), “01001b”

(bandwidth = 15.63 Hz), “01010b” (bandwidth = 31.25 Hz), “01011b” (bandwidth = 62.5 Hz),

“01100b” (bandwidth = 125 Hz), “01101b” (bandwidth = 250 Hz), “01110b” (bandwidth = 500

Hz), “01111b” (bandwidth = 1000 Hz), “1xxxxb” (bandwidth = 1000 Hz). Default value of (0x10)

bw (after reset) is “11111b”. It is recommended to actively use the range from “01000b” to

“01111b” only in order to be compatible with future products.

Table 38: Bandwidths, register (0x10)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

reserved

bw <4>

bw <3>

bw <2>

bw <1>

bw <0>

5.9 Power modes

(resets) suspend mode; default value of (0x11) suspend is “0”.

(0x11) lowpower_en = “1” (“0”) sets (resets) low-power mode, default value of (0x11)

lowpower_en is “0”.

The settings for (0x11) sleep_dur are “0000b” to “0101b” (sleep phase duration = 0.5 ms),

“0110b” (sleep phase duration = 1 ms), “0111b” (sleep phase duration = 2 ms), “1000b” (sleep

phase duration = 4 ms), “1001b” (sleep phase duration = 6 ms), “1010b” (sleep phase duration

= 10 ms), “1011b” (sleep phase duration = 25 ms), “1100b” (sleep phase duration = 50 ms),

“1101b” (sleep phase duration = 100 ms), “1110b” (sleep phase duration = 500 ms), “1111b”

(sleep phase duration = 1 s). Default value of (0x11) sleep_dur is “0000b”.

Table 39: Power modes, register (0x11)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

suspen

lowpowe

_en

reserve

sleep_

dur<3>

sleep_

dur<2>

sleep_

dur<1>

sleep_

dur<0>

reserve

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5.10 Special control settings

the data output format.

(0x13) data_high_bw = “0” (“1”) selects filtered (unfiltered) acceleration data to be written into

the data registers (0x02) to (0x07). Default value of (0x13) data_high_bw is “0”.

(0x13) shadow_dis = “0” (“1”) enables (disables) the shadowing procedure. Shadowing means

that the MSB register is updated by reading the corresponding LSB register. Default value of

(0x13) shadow_dis is “0”.

Table 40: Acceleration data acquisition & data output format, register (0x13)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

data_hig

_bw

shadow

_dis

reserved

reserve

performed after writing “0xB6h” to the softreset register. After that reset all registers return to

their default values. Reading (0x14) softreset returns 0x00.

5.11 Interrupt settings

Registers (0x16) and (0x17) contain the enable bits for the interrupts. Default value of each

enable bit is “0”.

Table 41: Interrupt setting, register (0x16)

(0x16) Bit

Name

Description

Bit 7

flat_en

“1” (“0”) enables (disables) flat interrupt

Bit 6

orient_en

“1” (“0”) enables (disables) orientation interrupt

Bit 5

s_tap_en

“1” (“0”) enables (disables) single tap interrupt

Bit 4

d_tap_en

“1” (“0”) enables (disables) double tap interrupt

Bit 3

- reserved -

reserved

Bit 2

slope_en_z

“1” (“0”) enables (disables) slope interrupt for z-axis

Bit 1

slope_en_y

“1” (“0”) enables (disables) slope interrupt for y-axis

Bit 0

slope_en_x

“1” (“0”) enables (disables) slope interrupt for x-axis

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Table 42: Interrupt setting, register (0x17)

(0x17) Bit

Name

Description

Bit 7

- reserved -

reserved

Bit 6

- reserved -

reserved

Bit 5

- reserved -

reserved

Bit 4

data_en

“1” (“0”) enables (disables) new data interrupt

Bit 3

low_en

“1” (“0”) enables (disables) low-g interrupt

Bit 2

high_en_z

“1” (“0”) enables (disables) high-g interrupt for z-axis

Bit 1

high_en_y

“1” (“0”) enables (disables) high-g interrupt for y-axis

Bit 0

high_en_x

“1” (“0”) enables (disables) high-g interrupt for x-axis

Registers (0x19) to (0x1B) contain the mapping of interrupts onto the interrupt pins. Default

value of each mapping bit is “0”.

Table 43: Interrupt mapping, register (0x19)

(0x19) Bit

Name

Description

Bit 7

int1_flat

“1” (“0”) maps (unmaps) flat interrupt to INT1 pin

Bit 6

int1_orient

“1” (“0”) maps (unmaps) orientation interrupt to INT1 pin

Bit 5

int1_s_tap

“1” (“0”) maps (unmaps) single tap interrupt to INT1 pin

Bit 4

int1_d_tap

“1” (“0”) maps (unmaps) double tap interrupt to INT1 pin

Bit 3

- reserved -

reserved

Bit 2

int1_slope

“1” (“0”) maps (unmaps) slope interrupt to INT1 pin

Bit 1

int1_high

“1” (“0) maps (unmaps) high-g interrupt to INT1 pin

Bit 0

int1_low

“1” (“0”) maps (unmaps) low-g interrupt to INT1 pin

Table 44: Interrupt mapping, register (0x1A)

(0x1A) Bit

Name

Description

Bit 7

int2_data

“1” (“0”) maps (unmaps) new data interrupt to INT2 pin

Bit 6

- reserved -

reserved

Bit 5

- reserved -

reserved

Bit 4

- reserved -

reserved

Bit 3

- reserved -

reserved

Bit 2

- reserved -

reserved

Bit 1

- reserved -

reserved

Bit 0

int1_data

“1” (“0”) maps (unmaps) new data interrupt to INT1 pin

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Table 45: Interrupt mapping, register (0x1B)

(0x1B) Bit

Name

Description

Bit 7

int2_flat

“1” (“0”) maps (unmaps) flat interrupt to INT2 pin

Bit 6

int2_orient

“1” (“0”) maps (unmaps) orientation interrupt to INT2 pin

Bit 5

int2_s_tap

“1” (“0”) maps (unmaps) single tap interrupt to INT2 pin

Bit 4

int2_d_tap

“1” (“0”) maps (unmaps) double tap interrupt to INT2 pin

Bit 3

- reserved -

reserved

Bit 2

int2_slope

“1” (“0”) maps (unmaps) slope interrupt to INT2 pin

Bit 1

int2_high

“1” (“0”) maps (unmaps) high-g interrupt to INT2 pin

Bit 0

int2_low

“1” (“0”) maps (unmaps) low-g interrupt to INT2 pin

Registers (0x1C) and (0x1D) are reserved.

source. Default value of each data source selection bit is “0”.

Table 46: Interrupt data source definition, register (0x1E)

(0x1E) Bit

Name

Description

Bit 7

- reserved -

reserved

Bit 6

- reserved -

reserved

Bit 5

int_src_data

“1” (“0”) selects unfiltered (filtered) data for the new data

interrupt

Bit 4

int_src_tap

“1” (“0”) selects unfiltered (filtered) data for the single tap

and

double tap interrupts

Bit 3

- reserved -

reserved

Bit 2

int_src_slope

“1” (“0”) selects unfiltered (filtered) data for the slope

interrupt

Bit 1

int_src_high

“1” (“0”) selects unfiltered (filtered) data for the high-g

interrupt

Bit 0

int_src_low

“1” (“0”) selects unfiltered (filtered) data for the low-g

interrupt

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pins. Default value of (0x20) int1_od and (0x20) int2_od is “0”. Default value of (0x20) int1_lvl

and (0x20) int2_lvl is “1”.

Table 47: Electrical behaviour of interrupt pin, register (0x20)

(0x20) Bit

Name

Description

Bit 7

- reserved -

reserved

Bit 6

- reserved -

reserved

Bit 5

- reserved -

reserved

Bit 4

- reserved -

reserved

Bit 3

int2_od

“0” selects push-pull, “1” selects open drive for INT2 pin

Bit 2

int2_lvl

“0” (“1”) selects active level “0” (“1”) for INT2 pin

Bit 1

int1_od

“0” selects push-pull, “1” selects open drive for INT1

Bit 0

int1_lvl

“0” (“1”) selects active level “0” (“1”) for INT1 pin

(0x21) reset_int resets any latched interrupt.

The settings for (0x21) latch_int are “0000b” (non-latched), “0001b” (temporary, 250 ms),

“0010b” (temporary, 500 ms), “0011b” (temporary, 1 s), ”0100b” (temporary, 2 s), ”0101b”

(temporary, 4 s), ”0110b” (temporary, 8 s), ”0111b” (latched), ”1000b” (non-latched), ”1001b”

(temporary, 500 s), ”1010b” (temporary, 500 s), ”1011b” (temporary, 1 ms), ”1100b”

(temporary, 12.5 ms), ”1101b” (temporary, 25 ms), ”1110b” (temporary, 50 ms), ”1111b”

(latched).

Default value of (0x21) latch_int is ”0000b”.

Table 48: Interrupt reset bit and interrupt mode selection, register (0x21)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

reset_int

reserved

latch_

int<3>

latch_

int<2>

latch_

int<1>

latch_

int<0>

time can be computed from the content of (0x22) low_dur according to:

delay [ms] = [(0x22) low_dur + 1] • 2 ms.

Possible delay times range from 2 ms to 512 ms. Default value of (0x22) low_dur is 0x09,

corresponding to a delay of 20 ms.

Table 49: Delay time definition for the low-g interrupt, register (0x22)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

low_

dur<7>

low_

dur<6>

low_

dur<5>

low_

dur<4>

low_

dur<3>

low_

dur<2>

low_

dur<1>

low_

dur<0>

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low_th corresponds to an actual acceleration of 7.81 mg. Therefore, the threshold ranges from 0

g to 1.992 g. Default value of (0x23) low_th is 0x30, corresponding to an acceleration of 375

mg.

Table 50: Threshold definition for the low-g interrupt, register (0x23)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

low_

th<7>

low_

th<6>

low_

th<5>

low_

th<4>

low_

th<3>

low_

th<2>

low_

th<1>

low_

th<0>

setting, and the high-g interrupt hysteresis setting. Setting (0x24) low_mode to ”0” (“1”) selects

´single´ mode (´sum´ mode). Default value is “0” (´single´ mode).

(0x24) low_hy sets the hysteresis of the low-g interrupt. An LSB of (0x24) low_hy corresponds

to an acceleration difference of 125 mg. Default value of (0x24) low_hy is “01b”.

(0x24) high_hy sets the hysteresis of the high-g interrupt. The meaning of an LSB of (0x24)

high_hy depends on the selected g-range. It corresponds to an acceleration difference of 125

mg in 2g-range, 250 mg in 4g-range, 500 mg in 8g-range, and 1000mg in 16g-range.

Default value of (0x24) high_hy is “10b”.

Table 51: Threshold definition for the low-g interrupt, register (0x24)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

high_

hy<1>

high_

hy<0>

reserved

low_

mode

low_

hy<1>

low_

hy<0>

time can be computed from the content of (0x25) high_dur according to

delay [ms] = [(0x22) high_dur + 1] • 2 ms. Possible delay times range from 2 ms to 512 ms.

Default value of (0x25) high_dur is 0x0F, corresponding to a delay of 32 ms.

Table 52: Delay time definition for the high-g interrupt, register (0x25)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

high_

dur<7>

high_

dur<6>

high_

dur<5>

high_

dur<4>

high_

dur<3>

high_

dur<2>

high_

dur<1>

high_

dur<0>

LSB of (0x26) high_th depends on the selected g-range. It corresponds to 7.81 mg in 2g-range,

15.63 mg in 4g-range, 31.25 mg in 8g-range, and 62.5 mg in 16g-range.

Default value of (0x26) high_th is 0xC0.

Table 53: Threshold definition for the high-g interrupt, register (0x26)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

high_

th<7>

high_

th<6>

high_

th<5>

high_

th<4>

high_

th<3>

high_

th<2>

high_

th<1>

high_

th<0>

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interrupt (any-motion detection). The number of samples is N = (0x27) slope_dur + 1.

Default value of (0x27) slope_dur is “00b”.

Table 54: Samples number definition for the slope interrupt, register (0x27)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

reserved

slope_

dur<1>

slope_

dur<0>

slope_th corresponds to an LSB of acceleration data. Its meaning therefore depends on the

selected g-range. Default value of (0x28) slope_th is 0x14.

Table 55: Samples number definition for the slope interrupt, register (0x28)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

slope_

th<7>

slope_

th<6>

slope_

th<5>

slope_

th<4>

slope_

th<3>

slope_

th<2>

slope_

th<1>

slope_

th<0>

(0x2A) tap_quiet = “0” (“1”) selects a quiet duration of 30 ms (20 ms). The default value of

(0x2A) tap_quiet is “0”.

(0x2A) tap_shock = “0” (“1”) selects a shock duration of 50 ms (75 ms). The default value of

(0x2A) tap_shock is “0”.

(0x2A) tap_dur selects the length of the time window for the second shock event (for double tap

detection). The settings for (0x2A) tap_dur are “000b” (50 ms), “001b” (100 ms), “010b” (150

ms), “011b” (200 ms), “100b” (250 ms), “101b” (375 ms), “110b” (500 ms), “111b” (700 ms). The

default value of (0x2A) tap_dur is “100b”.

Table 56: Tap Quiet duration and tap shock duration, register (0x2A)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

tap_

quiet

tap_

shock

reserved

tap_

dur<2>

tap_

dur<1>

tap_

dur<0>

up in low-power mode and the threshold definition for the single and double tap interrupts.

(0x2B) tap_samp selects the number of samples that are processed after wake-up in the low-

power mode. The settings for (0x2B) tap_samp are “00b” (2 samples), “01b” (4 samples), “10b”

(8 samples), and “11b” (16 samples). Default value of (0x2B) tap_samp is “00b”.

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The meaning of an LSB of (0x2B) tap_th depends on the selected g-range. It corresponds to an

acceleration difference of 62.5mg in 2g-range, 125mg in 4g-range, 250mg in 8g-range, and

500mg in 16g-range. Default value of (0x2B) tap_th is 0x0A.

Table 57: Samples number after wake-up and threshold tap interrupt, register (0x2B)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

tap_

samp<1>

tap_

samp<0>

reserved

tap_

th<4>

tap_

th<3>

tap_

th<2>

tap_

th<1>

tap_

th<0>

interrupt. (0x2C) orient_hyst sets the hysteresis of the orientation interrupt; 1 LSB always

corresponds to 62.5 mg, in any g-range (i.e. increment is independent from g-range setting).

Default value of (0x2C) orient_hyst is “001b”.

(0x2C) orient_blocking selects the kind of blocking that is used for the generation of the

orientation interrupt. The settings for (0x2C) orient_blocking are “00b” (no blocking), “01b” (theta

blocking), “10b” (theta blocking or slope in any axis > 0.2 g), and “11b” (orient value not stable

for at least 100 ms or theta blocking or slope in any axis > 0.4 g). Default value of (0x2C)

orient_blocking is “10b”.

(0x2C) orient_mode sets the thresholds for switching between the different orientations. The

settings for (0x2C) orient_mode are “00b” (symmetrical), “01b” (high-asymmetrical), “10b” (low-

asymmetrical), “11b” (symmetrical). Default value of (0x2C) orient_mode is “00b”.

Table 58: Hysteresis, Blocking for Orientation Interrupt, Register (0x2C)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

reserved

orient_

hyst<2

orient_

hyst<1

orient_

hyst<0

orient_

blocking<1>

orient_

blocking<0>

orient_

mode<1

orient_

mode<0

(0x2D) orient_theta defines a blocking angle between 0° and 44.8° as described in chapter

4.8.7.1. Default value of (0x2D) orient_theta is 0x08.

Table 59: Theta blocking angle, register (0x2D)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

reserved

orient_

theta<5>

orient_

theta<4>

orient_

theta<3>

orient_

theta<2>

orient_

theta<1>

orient_

theta<0>

flat_theta defines a blocking angle between 0° and 44.8° as described in chapter 4.8.8. Default

value of (0x2E) flat_theta is 0x08.

Table 60: Flat threshold angle, register (0x2E)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

reserved

flat_

theta<5>

flat_

theta<4>

flat_

theta<3>

flat_

theta<2>

flat_

theta<1>

flat_

theta<0>

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time a new flat value has to be at least stable for before the interrupt is generated. The settings

for (0x2F) flat_hold_time are “00b” (0), “01b” (512 ms), “10b” (1024 ms), “11b” (2048 ms).

Default value of (0x2F) flat_hold_time is “01b”.

Table 61: Flat threshold angle, register (0x2F)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

reserved

flat_hold_

time<1>

flat_hold_

time<0>

reserved

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5.12 Self-test

(0x32) self_test_sign sets the sign of the electrostatic excitation. The settings for (0x32)

self_test_sign are “0” (positive sign) and “1” (negative sign). Default value of (0x32)

self_test_sign is “0”.

(0x32) self_test_axis defines the axis which shall be excited. Only one axis can be excited at

the same time. The settings for (0x32) self_test_axis are “00b” (no self-test), “01” (x-axis), “10”

(y-axis), and “11” (z-axis). Default value of (0x32) self_test_axis is “00b”.

Table 62: Sensor self-test, register (0x32)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

reserved

self_test

_sign

self_test

_axis<1>

self_test

_axis<0>

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5.13 Non-volatile memory control (EEPROM control)

nvm_load is used to perform a user-defined image update. Writing “1” (0x33) nvm_load starts

the update procedure. The value “1” is kept as long as the update procedure runs, afterwards it

is reset to “0”.

(0x33) nvm_rdy contains the status of writing the EEPROM. (0x33) nvm_rdy is “0” as long as

writing the EEPROM endures, it is “1” if currently no write access is performed and, therefore, a

new write access can be initiated.

Writing “1”to (0x33) nvm_prog_trig triggers writing the EEPROM. The EEPROM can only be

written if it was unlocked before.

Writing “1”to (0x33) nvm_prog_mode unlocks the EEPROM.

Table 63: EEPROM control settings, register (0x33)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

reserved

nvm_load

nvm_rdy

nvm_prog

_trig

nvm_prog

_mode

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5.14 Interface configuration

enables the watchdog at the SDI pin (= SDA for I²C) if I²C is selected. Default value of (0x34)

i2c_wdt_en is “0”.

(0x34) i2c_wdt_sel selects the I²C data pad watchdog timer period. The settings for (0x34)

i2c_wdt_sel are “0” (1 ms) and “1” (50 ms). Default value of (0x34) i2c_wdt_sel is “0”.

(0x34) spi3 selects the SPI mode. The settings for (0x34) spi3 are “0” (4-wire SPI) and “1” (3-

wire SPI). Default value of (0x34) spi3 is “0”.

Table 64: EEPROM control settings, register (0x34)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

reserved

i2c_wdt

_en

i2c_wdt

_sel

spi3

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5.15 Offset compensation

compensation, and for slow offset compensation. Writing “1”to (0x36) offset_reset sets all offset

compensation registers (0x38 to 0x3D) to zero.

Default value of (0x36) offset_reset is “0”.

(0x36) cal_trigger starts the fast compensation process for the specified axis. The settings for

(0x36) cal_trigger are “00b” (no axis selected), “01b” (x-axis), “10b” (y-axis), “11b” (z-axis). A

non-zero value is kept until the fast compensation procedure is finished. Default value of (0x36)

cal_trigger is “00b”.

(0x36) cal_rdy indicates the state of the fast compensation. (0x36) cal_rdy is “0” when (0x36)

cal_trigger has a nonzero value, otherwise (0x36) cal_rdy is “1”.

Writing “1” (“0”) to (0x36) hp_z_en enables (disables) slow offset compensation for the z-axis.

Writing “1” (“0”) to (0x36) hp_y_en enables (disables) slow offset compensation for the y-axis.

Writing “1” (“0”) to (0x36) hp_x_en enables (disables) slow offset compensation for the x-axis.

Default value for each of (0x36) hp_x_en, (0x36) hp_y_en, and (0x36) hp_x_en is “0”,

respectively.

Table 65: Offset compensation, fast offset compensation, register (0x36)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

offset

_reset

cal_

trigger<1>

cal_

trigger<0>

cal_rdy

reserved

hp_z_en

hp_y_en

hp_x_en

compensation. (0x37) offset_target_z sets the target value for the offset compensation of the z-

axis.

(0x37) offset_target_y sets the target value for the offset compensation of the y-axis.

(0x37) offset_target_x sets the target value for the offset compensation of the x-axis.

The settings for (0x37) offset_target_x, (0x37) offset_target_y, and (0x37) offset_target_z are

“00b” (0 g), “01b” (+1 g), “10b” (-1 g), and “11b” (0 g). Default value of each of (0x37)

offset_target_x, (0x37) offset_target_y, and (0x37) offset_target_z is “00b”, respectively.

(0x37) cut_off defines the number of samples for comparison by the slow offset compensation.

The settings for (0x37) cut_off are “0” (8 samples) and “1” (16 samples). The default value of

(0x37) cut_off is “0”.

Table 66: Offset compensation, slow offset compensation, register (0x37)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

reserve

offset_ta

rget_z<

offset_ta

rget_z<

offset_ta

rget_y<

offset_ta

rget_y<

offset_ta

rget_x<

offset_ta

rget_x<

cut_off

each of the registers (0x38) to (0x3D) is added to the corresponding acceleration data; it can be

set either automatically by one of the implemented compensation algorithms or manually. These

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registers are image registers of registers in the EEPROM; the content of the EEPROM is copied

to them after every reset.

Table 67: Filtered data compensation for the x-axis, register (0x38)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

offset_

filt_x<7>

offset_

filt_x<6>

offset_

filt_x<5>

offset_

filt_x<4>

offset_

filt_x<3>

offset_

filt_x<2>

offset_

filt_x<1>

offset_

filt_x<0>

Table 68: Filtered data compensation for the y-axis, register (0x39)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

offset_

filt_y<7>

offset_

filt_y<6>

offset_

filt_y<5>

offset_

filt_y<4>

offset_

filt_y<3>

offset_

filt_y<2>

offset_

filt_y<1>

offset_

filt_y<0>

Table 69: Filtered data compensation for the z-axis, register (0x3A)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

offset_

filt_z<7>

offset_

filt_z<6>

offset_

filt_z<5>

offset_

filt_z<4>

offset_

filt_z<3>

offset_

filt_z<2>

offset_

filt_z<1>

offset_

filt_z<0>

Table 70: Unfiltered data compensation for the x-axis, register (0x3B)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

offset_

unfilt_x

<7>

offset_

unfilt_x

<6>

offset_

unfilt_x

<5>

offset_

unfilt_x

<4>

offset_

unfilt_x

<3>

offset_

unfilt_x

<2>

offset_

unfilt_x

<1>

offset_

unfilt_x

<0>

Table 71: Unfiltered data compensation for the x-axis, register (0x3C)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

offset_

unfilt_y

<7>

offset_

unfilt_y

<6>

offset_

unfilt_y

<5>

offset_

unfilt_y

<4>

offset_

unfilt_y

<3>

offset_

unfilt_y

<2>

offset_

unfilt_y

<1>

offset_

unfilt_y

<0>

Table 72: Unfiltered data compensation for the y-axis, register (0x3D)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

offset_

unfilt_z

<7>

offset_

unfilt_z

<6>

offset_

unfilt_z

<5>

offset_

unfilt_z

<4>

offset_

unfilt_z

<3>

offset_

unfilt_z

<2>

offset_

unfilt_z

<1>

offset_

unfilt_z

<0>

Registers (0x3E) and (0x3F) are image registers of registers in the EEPROM. They are not

linked to any sensor-specific functionality.

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6. Magnetometer register description

6.1 General remarks

The entire communication with the device‟s magnetometer part is performed by reading from

and writing to registers. Registers have a width of 8 bits; they are mapped to a common space

of 50 addresses from (0x40) up to (0x71). Within the used range there are several registers

which are marked as „reserved‟. Any reserved bit is ignored when it is written and no specific

value is guaranteed when read. Especially, in SPI mode the SDO pin may stay in high-Z state

when reading some of these registers.

Registers with addresses from (0x40) up to (0x4A) are read-only. Any attempt to write to these

registers is ignored.

6.2 Register map

0x71 N/A

0x70 N/A

0x6F N/A

0x6E N/A

0x6D N/A

0x6C N/A

0x6B N/A

0x6A N/A

0x69 N/A

0x68 N/A

0x67 N/A

0x66 N/A

0x65 N/A

0x64 N/A

0x63 N/A

0x62 N/A

0x61 N/A

0x60 N/A

0x5F N/A

0x5E N/A

0x5D N/A

0x5C N/A

0x5B N/A

0x5A N/A

0x59 N/A

0x58 N/A

0x57 N/A

0x56 N/A

0x55 N/A

0x54 N/A

0x53 N/A

0x52 0x00

0x51 0x00

0x50 0x00

0x4F 0x00

0x4E 0x07 Data Ready Pin En Interrupt Pin En Channel Z Channel Y Channel X DR Polarity Interrupt Latch Interrupt Polarity

0X4D 0x3F Data Overrun En Overflow Int En High Int Z en High Int Y en High Int X en Low Int Z en Low Int Y en Low Int X en

0x4C 0x06 Self Test

0x4B 0x01 Soft Reset '1' fixed '0' fixed '0' fixed '0' fixed '0' SPI3en Soft Reset '1' Power Control Bit

0x4A 0x00 Data Overrun Overflow High Int Z High Int Y High Int X Low Int Z Low Int Y Low Int X

0x49 N/A

0x48 N/A fixed '0' Data Ready Status

0x47 N/A

0x46 N/A Z-Self-Test

0x45 N/A

0x44 N/A fixed '0' fixed '0' Y-Self-Test

0x43 N/A

0x42 N/A fixed '0' fixed '0' X-Self-Test

0x41 N/A

0x40 0x32

w/r

w/r accessible

in suspend mode

read only

reserved

Chip ID = 0x32 (can only be read if power control bit ="1")

REPZ Number Of Repetitions (valid for Z) [7:0]

REPXY Number Of Repetitions (valid for XY) [7:0]

DATA X [12:5] MSB

DATA X [4:0] LSB

DATA Z [14:7] MSB

RHALL [5:0] LSB

DATA Y [12:5] MSB

DATA Y [4:0] LSB

High Threshold [7:0]

Low Threshold [7:0]

Adv. ST [1:0]

Data Rate [2:0]

DATA Z [6:0] LSB

Opmode [1:0]

RHALL [13:6] MSB

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6.3 Chip ID

This number can only be read if the power control bit (register 0x4B bit0) is enabled.

Table 73: Chip identification number, register (0x40)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

6.4 Magnetic field data

for the x-axis.

Table 74: LSB part of x-axis magnetic field, register (0x42)

(0x42) Bit

Name

Description

Bit 7

DATAX_lsb <4>

Bit 4 of x-axis magnetic field data

Bit 6

DATAX_lsb <3>

Bit 3 of x-axis magnetic field data

Bit 5

DATAX_lsb <2>

Bit 2 of x-axis magnetic field data

Bit 4

DATAX_lsb <1>

Bit 1 of x-axis magnetic field data

Bit 3

DATAX_lsb <0>

Bit 0 of x-axis magnetic field data = x LSB

Bit 2

(fixed to 0)

Bit 1

(fixed to 0)

Bit 0

SelfTestX

Self-test result flag for x-axis, default is “1”

Table 75: MSB part of x-axis magnetic field, register (0x43)

(0x43)

Bit

Name

Description

Bit 7

DATAX_msb <12>

Bit 12 of x-axis magnetic field data = x MSB

Bit 6

DATAX_msb <11>

Bit 11 of x-axis magnetic field data

Bit 5

DATAX_msb <10>

Bit 10 of x-axis magnetic field data

Bit 4

DATAX_msb <9>

Bit 9 of x-axis magnetic field data

Bit 3

DATAX_msb <8>

Bit 8 of x-axis magnetic field data

Bit 2

DATAX_msb <7>

Bit 7 of x-axis magnetic field data

Bit 1

DATAX_msb <6>

Bit 6 of x-axis magnetic field data

Bit 0

DATAX_msb <5>

Bit 5 of x-axis magnetic field data

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for the y-axis.

Table 76: LSB part of y-axis magnetic field, register (0x44)

(0x44) Bit

Name

Description

Bit 7

DATAY_lsb <4>

Bit 4 of y-axis magnetic field data

Bit 6

DATAY_lsb <3>

Bit 3 of y-axis magnetic field data

Bit 5

DATAY_lsb <2>

Bit 2 of y-axis magnetic field data

Bit 4

DATAY_lsb <1>

Bit 1 of y-axis magnetic field data

Bit 3

DATAY_lsb <0>

Bit 0 of y-axis magnetic field data = y LSB

Bit 2

(fixed to 0)

Bit 1

(fixed to 0)

Bit 0

SelfTestY

Self-test result flag for y-axis, default is “1”

Table 77: MSB part of y-axis magnetic field, register (0x45)

(0x43)

Bit

Name

Description

Bit 7

DATAY_msb <12>

Bit 12 of y-axis magnetic field data = y MSB

Bit 6

DATAY_msb <11>

Bit 11 of y-axis magnetic field data

Bit 5

DATAY_msb <10>

Bit 10 of y-axis magnetic field data

Bit 4

DATAY_msb <9>

Bit 9 of y-axis magnetic field data

Bit 3

DATAY_msb <8>

Bit 8 of y-axis magnetic field data

Bit 2

DATAY_msb <7>

Bit 7 of y-axis magnetic field data

Bit 1

DATAY_msb <6>

Bit 6 of y-axis magnetic field data

Bit 0

DATAY_msb <5>

Bit 5 of y-axis magnetic field data

for the z-axis.

Table 78: LSB part of z-axis magnetic field, register (0x44)

(0x44) Bit

Name

Description

Bit 7

DATAZ_lsb <6>

Bit 6 of z-axis magnetic field data

Bit 6

DATAZ_lsb <5>

Bit 5 of z-axis magnetic field data

Bit 5

DATAZ_lsb <4>

Bit 4 of z-axis magnetic field data

Bit 4

DATAZ_lsb <3>

Bit 3 of z-axis magnetic field data

Bit 3

DATAZ_lsb <2>

Bit 2 of z-axis magnetic field data

Bit 2

DATAZ_lsb <1>

Bit 1 of z-axis magnetic field data

Bit 1

DATAZ_lsb <0>

Bit 0 of z-axis magnetic field data = z LSB

Bit 0

SelfTestZ

Self-test result flag for z-axis, default is “1”

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Table 79: MSB part of z-axis magnetic field, register (0x45)

(0x45)

Bit

Name

Description

Bit 7

DATAZ_lsb <14>

Bit 14 of y-axis magnetic field data = z MSB

Bit 6

DATAZ_lsb <13>

Bit 13 of y-axis magnetic field data

Bit 5

DATAZ_lsb <12>

Bit 12 of y-axis magnetic field data

Bit 4

DATAZ_lsb <11>

Bit 11 of y-axis magnetic field data

Bit 3

DATAZ_lsb <10>

Bit 10 of y-axis magnetic field data

Bit 2

DATAZ_lsb <9>

Bit 9 of y-axis magnetic field data

Bit 1

DATAZ_lsb <8>

Bit 8 of y-axis magnetic field data

Bit 0

DATAZ_lsb <7>

Bit 7 of y-axis magnetic field data

Table 80: LSB part of hall resistance, register (0x46)

(0x46) Bit

Name

Description

Bit 7

RHALL_lsb <5>

Bit 5 of hall resistance

Bit 6

RHALL _lsb <4>

Bit 4 of hall resistance

Bit 5

RHALL _lsb <3>

Bit 3 of hall resistance

Bit 4

RHALL _lsb <2>

Bit 2 of hall resistance

Bit 3

RHALL _lsb <1>

Bit 1 of hall resistance

Bit 2

RHALL _lsb <0>

Bit 0 of hall resistance = RHALL LSB

Bit 1

(fixed to 0)

Bit 0

Data Ready Status

Data ready (DRDY) status bit

Table 81: MSB part of hall resistance, register (0x47)

(0x47)

Bit

Name

Description

Bit 7

RHALL_msb <13>

Bit 13 of hall resistance = RHALL MSB

Bit 6

RHALL_msb <12>

Bit 12 of hall resistance

Bit 5

RHALL_msb <11>

Bit 11 of hall resistance

Bit 4

RHALL_msb <10>

Bit 10 of hall resistance

Bit 3

RHALL_msb <9>

Bit 9 of hall resistance

Bit 2

RHALL_msb <8>

Bit 8 of hall resistance

Bit 1

RHALL_msb <7>

Bit 7 of hall resistance

Bit 0

RHALL_msb <6>

Bit 6 of hall resistance

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6.5 Interrupt status register

Table 82: Interrupt status, register (0x4A)

(0x4A)

Bit

Name

Description

Bit 7

Data overrun

Data overrun status flag

Bit 6

Overflow

Overflow status flag

Bit 5

High Int Z

High-Threshold interrupt z-axis status flag

Bit 4

High Int Y

High-Threshold interrupt y-axis status flag

Bit 3

High Int X

High-Threshold interrupt x-axis status flag

Bit 2

Low Int Z

Low-Threshold interrupt z-axis status flag

Bit 1

Low Int Y

Low-Threshold interrupt y-axis status flag

Bit 0

Low Int X

Low-Threshold interrupt x-axis status flag

6.6 Power and operation modes, self-test and data output rate control registers

selection. This special control register is also accessible in suspend mode.

Soft reset is executed when both bits (register 0x4B bit7 and bit1) are set “1”. Soft reset does

not execute a full POR sequence, but all registers are reset except for the “trim” registers above

sleep mode. When device is in the suspend mode, soft reset is ignored and the device remains

in suspend mode. The two “Soft Reset” bits are reset to “0” automatically after soft reset was

completed.

When SPI mode is selected, the “SPI3En” bit enables SPI 3-wire mode when set “1”. When

“SPI3En” is set “0” (default), 4-wire SPI mode is selected.

Setting the “Power Control bit” to “1” brings the device up from Suspend mode to Sleep mode,

when “Power Control bit” is set “0” the device returns to Suspend mode (see chapter 4.3.2 for

details of magnetometer power modes).

Table 83: Power control, soft reset and SPI mode control register (0x4B)

(0x4B)

Bit

Name

Description

Bit 7

Soft Reset ‘1’

One of the soft reset trigger bits.

Bit 6

(fixed to 0)

Bit 5

(fixed to 0)

Bit 4

(fixed to 0)

Bit 3

(fixed to 0)

Bit 2

SPI3en

Enable bit for SPI3 mode

Bit 1

Soft Reset ‘1’

One of the soft reset trigger bits.

Bit 0

Power Control bit

When set to “0”, suspend mode is selected

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The two “Adv. ST” bits control the on-chip advanced self-test (see chapter 4.5.2 for details of the

magnetometer advanced self-test).

The three “Data rate” bits control the magnetometer output data rate according to below Table

85.

The two “Opmode” bits control the operation mode according to below Table 86 (see chapter

4.3.2 for a detailed description of magnetometer power modes).

Table 84: Operation mode, output data rate and self-test control register (0x4C)

(0x4C)

Bit

Name

Description

Bit 7

Adv. ST <1>

Advanced self-test control bit 1

Bit 6

Adv. ST <0>

Advanced self-test control bit 0

Bit 5

Data rate <2>

Data rate control bit 2

Bit 4

Data rate <1>

Data rate control bit 1

Bit 3

Data rate <0>

Data rate control bit 0

Bit 2

Opmode <1>

Operation mode control bit 1

Bit 1

Opmode <0>

Operation mode control bit 0

Bit 0

Self Test

Normal self-test control bit

Three “Data rate” bits control the output data rate (ODR) of the BMC050 magnetometer part:

Table 85: Output data rate (ODR) setting (0x4C)

(0x4C)

Data rate <2:0>

Magnetometer output data rate

(ODR)

000b

10 (default)

001b

010b

011b

100b

101b

110b

111b

Two “Data rate” bits control the operation mode of the BMC050 magnetometer part:

Table 86: Operation mode setting (0x4C)

(0x4C)

Opmode <1:0>

Magnetometer operation mode4

00b

Normal mode

01b

Forced mode

10b

Reserved, do not use

11b

Sleep Mode

See chapter 4.3.2 for a detailed description of magnetometer power modes.

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6.7 Interrupt and axis enable settings control registers

details of magnetometer interrupt operation).

Table 87: Interrupt settings control register (0x4D)

(0x4D)

Bit

Name

Description

Bit 7

Data Overrun En

Enables data overrun indication in the “Data

Overrun” flag (active high, default is “0” disabled)

Bit 6

Overflow Int En

Activates mapping of Overflow flag status to the

INT3 pin

(active high, default is “0” disabled)

Bit 5

High Int Z En

Enables the z-axis detection for High-Threshold

interrupts (active low, default is “1” disabled)

Bit 4

High Int Y En

Enables the y-axis detection for High-Threshold

interrupts (active low, default is “1” disabled)

Bit 3

High Int X En

Enables the x-axis detection for High-Threshold

interrupts (active low, default is “1” disabled)

Bit 2

Low Int Z En

Enables the z-axis detection for Low-Threshold

interrupts (active low, default is “1” disabled)

Bit 1

Low Int Y En

Enables the y-axis detection for Low-Threshold

interrupts (active low, default is “1” disabled)

Bit 0

Low Int X En

Enables the x-axis detection for Low-Threshold

interrupts (active low, default is “1” disabled)

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chapter 4.9 for the details of magnetometer interrupt operation). If a magnetic measurement

channel is disabled, its last measured magnetic output values will remain in the data registers. If

the Z channel is disabled, the resistance measurement will also be disabled and the resistance

output value will be set to zero. If interrupts are set to trigger on an axis that has been disabled,

these interrupts will still be asserted based on the last measured value.

Table 88: Interrupt settings and axes enable bits control register (0x4E)

(0x4E)

Bit

Name

Description

Bit 7

Data Ready Pin En

Enables data ready status mapping on DRDY pin

(active high, default is “0” disabled)

Bit 6

Interrupt Pin En

Enables interrupt status mapping on INT3 pin

(active high, default is “0” disabled)

Bit 5

Channel Z

Enable z-axis and resistance measurement (active

low, default is “0” enabled)

Bit 4

Channel Y

Enable y-axis (active low, default is “0” enabled)

Bit 3

Channel X

Enable x-axis (active low, default is “0” enabled)

Bit 2

DR Polarity

Data ready (DRDY) pin polarity (“0” is active low,

“1” is active high, default is “1” active high)

Bit 1

Interrupt Latch

Interrupt latching (“0” means non-latched -

interrupt pin is on as long as the condition is

fulfilled, “1” means latched - interrupt pin is on until

interrupt status register 0x4A is read, default is „”1”

latched)

Bit 0

Interrupt Polarity

Interrupt pin INT3 polarity selection (“1” – is active

high, “0” is active low, default is “1” active high)

4.9 for the details of magnetometer interrupt operation and the threshold setting).

Table 89: Low-threshold interrupt threshold setting control register (0x4F)

(0x4F)

Bit

Name

Description

Bit 7

LowThreshold <7>

Bit 7 of Low-Threshold interrupt threshold setting

Bit 6

LowThreshold <6>

Bit 6 of Low-Threshold interrupt threshold setting

Bit 5

LowThreshold <5>

Bit 5 of Low-Threshold interrupt threshold setting

Bit 4

LowThreshold <4>

Bit 4 of Low-Threshold interrupt threshold setting

Bit 3

LowThreshold <3>

Bit 3 of Low-Threshold interrupt threshold setting

Bit 2

LowThreshold <2>

Bit 2 of Low-Threshold interrupt threshold setting

Bit 1

LowThreshold <1>

Bit 1 of Low-Threshold interrupt threshold setting

Bit 0

LowThreshold <0>

Bit 0 of Low-Threshold interrupt threshold setting

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4.9 for the details of magnetometer interrupt operation and the threshold setting).

Table 90: High-threshold interrupt threshold setting control register (0x4F)

(0x50)

Bit

Name

Description

Bit 7

HighThreshold <7>

Bit 7 of High-Threshold interrupt threshold setting

Bit 6

HighThreshold <6>

Bit 6 of High-Threshold interrupt threshold setting

Bit 5

HighThreshold <5>

Bit 5 of High-Threshold interrupt threshold setting

Bit 4

HighThreshold <4>

Bit 4 of High-Threshold interrupt threshold setting

Bit 3

HighThreshold <3>

Bit 3 of High-Threshold interrupt threshold setting

Bit 2

HighThreshold <2>

Bit 2 of High-Threshold interrupt threshold setting

Bit 1

HighThreshold <1>

Bit 1 of High-Threshold interrupt threshold setting

Bit 0

HighThreshold <0>

Bit 0 of High-Threshold interrupt threshold setting

6.8 Number of repetitions control registers

number of repetitions resulting out of the register configuration. The performed number of

repetitions nXY can be calculated from unsigned register value as nXY = 1+2xREPXY as shown

below, where b7-b0 are the bits 7 to 0 of register 0x51:

)(





202122232425262721 01234567

Table 91: X/y-axis repetitions control register (0x51)

Name

Description

Bit 7

REPXY <7>

Bit 7 of number of repetitions (valid for XY)

Bit 6

REPXY <6>

Bit 6 of number of repetitions (valid for XY)

Bit 5

REPXY <5>

Bit 5 of number of repetitions (valid for XY)

Bit 4

REPXY <4>

Bit 4 of number of repetitions (valid for XY)

Bit 3

REPXY <3>

Bit 3 of number of repetitions (valid for XY)

Bit 2

REPXY <2>

Bit 2 of number of repetitions (valid for XY)

Bit 1

REPXY <1>

Bit 1 of number of repetitions (valid for XY)

Bit 0

REPXY <0>

Bit 0 of number of repetitions (valid for XY)

Table 92: Numbers of repetition for x/y-axis depending on value of register (0x51)

(0x51) register

value (binary)

(0x51) register value

(hex)

Number of repetitions for x- and y-

axis each

00000000b

0x00h

00000001b

0x01h

00000010b

0x02h

00000011b

0x03h

…

11111111b

0xFFh

511

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number of repetitions resulting out of the register configuration. The performed number of

repetitions nZ can be calculated from unsigned register value as nZ = 1+REPZ as shown below,

where b7-b0 are the bits 7 to 0 of register 0x52:





202122232425262711 01234567 )(

Table 93: Z-axis repetitions control register (0x52)

(0x52)

Bit

Name

Description

Bit 7

REPZ <7>

Bit 7 of number of repetitions (valid for Z)

Bit 6

REPZ <6>

Bit 6 of number of repetitions (valid for Z)

Bit 5

REPZ <5>

Bit 5 of number of repetitions (valid for Z)

Bit 4

REPZ <4>

Bit 4 of number of repetitions (valid for Z)

Bit 3

REPZ <3>

Bit 3 of number of repetitions (valid for Z)

Bit 2

REPZ <2>

Bit 2 of number of repetitions (valid for Z)

Bit 1

REPZ <1>

Bit 1 of number of repetitions (valid for Z)

Bit 0

REPZ <0>

Bit 0 of number of repetitions (valid for Z)

Table 94: Numbers of repetition for z-axis depending on value of register (0x52)

(0x52) register

value (binary)

(0x52) register value

(hex)

Number of repetitions for z-axis

00000000b

0x00h

00000001b

0x01h

00000010b

0x02h

00000011b

0x03h

…

11111111b

0xFFh

256

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7. Digital interfaces

The BMC050 supports two serial digital interface protocols for communication as a slave with a

host device for each of the accelerometer and magnetometer part: SPI and I²C (accelerometer

part and magnetometer part only operate either both in I²C mode or either both in SPI mode,

mixed communication protocols are not possible because the interface pins are shared).

The active interface is selected by the state of the two “protocol select” pins, Pin#2 (PS1) and

Pin#3 (PS2): “0” (“1”) selects SPI (I²C). For details see chapter 4.2.

By default, SPI operates in the standard 4-wire configuration. It can be re-configured by

software to work in 3-wire mode instead of standard 4-wire mode for both the accelerometer

part and magnetometer part.

Both interfaces share the same pins. The mapping for each interface is given in the following

table:

Table 95: Mapping of the interface pins

Pin#

Name

use w/

SPI

use w/ I²C

Description

SDO

Accelerometer and

magnetometer part

I²C address

selection

SPI: Data Output (4-wire mode)

I²C: Used to set LSB of I²C address of

accelerometer part and magnetometer part

SDx

SDI

SDA

SPI: Data Input (4-wire mode) Data Input / Output

(3-wire mode)

I²C: Serial Data

CSB15

CSB1

Unused, do not

connect

SPI: Chip Select 1 for accelerometer part (enable)

CSB25

CSB2

Magnetometer part

I²C address

selection

SPI: Chip Select 2 for magnetometer part (enable)

I²C: Used to set bit1 of I²C address of

magnetometer part

SCx

SCK

SCL

SPI: Serial Clock

I²C: Serial Clock

note: CSB1 and CSB2 must be operated separately and cannot be tied together.

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The following table shows the electrical specifications of the interface pins:

Table 96: Electrical specification of the interface pins

Parameter

Symbol

Condition

Min

Typ

Max

Unit

Pull-up Resistance

CSB1

Rup, CSB1

Internal Pull-up

Resistance to VDDIO

120

190

k

Pull-up Resistance

CSB2

Rup, CSB2

Internal Pull-up

Resistance to VDDIO;

deactivated in I²C mode

100

120

k

Input Capacitance

Cin

I²C Bus Load

Capacitance (max.

drive capability)

CI2C_Load

400

7.1 Serial peripheral interface (SPI)

The timing specification for SPI of the BMC050 is given in the following table:

Table 97: SPI timing for BMC050 accelerometer and magnetometer part

Parameter

Symbol

Condition

Min

Max

Unit

Clock Frequency

fSPI

Max. Load on SDI or

SDO = 25pF

MHz

SCK Low Pulse

tSCKL

SCK High Pulse

tSCKH

SDI Setup Time

tSDI_setup

SDI Hold Time

tSDI_hold

SDO Output Delay

tSDO_OD

Load = 25pF

Load = 250pF,

VDDIO = 2.4V

CSB Setup Time

tCSB_setup

CSB Hold Time

tCSB_hold

The following figure shows the definition of the SPI timings given in Table 97:

Figure 16: SPI timing diagram

tSDI_hold

tSCKH

tCSB_hold

tCSB_setup

tSDI_setup

tSCKL

tSDO_OD

CSB

SCK

SDI

SDO

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The SPI interface of the BMC050 is compatible with two modes, “00” and “11”. The automatic

selection between [CPOL = “0” and CPHA = “0”] and [CPOL = “1” and CPHA = “1”] is done

based on the value of SCK after a falling edge of CSB.

Two configurations of the SPI interface are supported by the BMC050: 4-wire and 3-wire. The

same protocol is used by both configurations. The device operates in 4-wire configuration by

default. It can be switched to 3-wire configuration by writing “1” to (0x34) “spi3” for the

accelerometer part and writing “1” to (0x4B) “SPI3en” for the magnetometer part (after power

control bit was set). Pin SDI is used as the common data pin in 3-wire configuration.

For single byte read as well as write operations, 16-bit protocols are used. The BMC050 also

supports multiple-byte read operations.

Note: CSB1 and CSB2 pin are separate chip select lines for accelerometer and magnetometer

part, which must be operated separately. Tying them together is strictly forbidden, since this will

make the accelerometer and magnetometer outputs compete against each other.

In SPI 4-wire configuration CSB1 or CSB2 (chip select low active), SCK (serial clock), SDI

(serial data input), and SDO (serial data output) pins are used. The communication starts when

the CSB is pulled low by the SPI master and stops when CSB is pulled high. SCK is also

controlled by SPI master. SDI and SDO are driven at the falling edge of SCK and should be

captured at the rising edge of SCK.

The basic write operation waveform for 4-wire configuration is depicted in Figure 17. During the

entire write cycle SDO remains in high- impedance state.

CSB

SCK

SDI

R/W

AD6

AD5

AD4

AD3

AD2

AD1

AD0

DI5

DI4

DI3

DI2

DI1

DI0

DI7

DI6

SDO

tri-state

Figure 17: 4-wire basic SPI write sequence (mode “11”)

The basic read operation waveform for 4-wire configuration is depicted in Figure 18:

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Figure 18: 4-wire basic SPI read sequence (mode “11”)

The data bits are used as follows:

Bit0: Read/Write bit. When 0, the data SDI is written into the chip. When 1, the data SDO from

the chip is read.

Bit1-7: Address AD(6:0).

Bit8-15: when in write mode, these are the data SDI, which will be written into the address.

When in read mode, these are the data SDO, which are read from the address.

Multiple read operations are possible by keeping CSB low and continuing the data transfer.

Only the first register address has to be written. Addresses are automatically incremented after

each read access as long as CSB stays active low.

The principle of multiple read is shown in Figure 19:

Figure 19: SPI multiple read

In SPI 3-wire configuration CSB1 or CSB2 (chip select low active), SCK (serial clock), and

SDI (serial data input and output) pins are used. The communication starts when the CSB is

pulled low by the SPI master and stops when CSB is pulled high. SCK is also controlled by SPI

master. SDI is driven (when used as input of the device) at the falling edge of SCK and should

be captured (when used as the output of the device) at the rising edge of SCK.

The protocol as such is the same in 3-wire configuration as it is in 4-wire configuration. The

basic operation waveform (read or write access) for 3-wire configuration is depicted in Figure

20:

Start

RW Stop

10000010XXXXXXXXXXXXXXXXXXXXXXXX

CSB

Data byte

Data register - adress 03h

Data register - adress 04h

Control byte

Data byte

Data register - adress 02h

R/W

AD1

stat

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CSB

SCK

SDI

AD6

AD5

AD4

AD3

AD2

AD1

AD0

DI5

DI4

DI3

DI2

DI1

DI0

DI7

DI6

Figure 20: 3-wire basic SPI read or write sequence (mode “11”)

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7.2 Inter-Integrated Circuit (I²C)

The I²C bus uses SCL (= SCx pin, serial clock) and SDA (= SDx pin, serial data input and

output) signal lines. Both lines are connected to VDDIO externally via pull-up resistors so that they

are pulled high when the bus is free.

The I²C interface of the BMC050 is compatible with the I²C Specification UM10204 Rev. 03 (19

June 2007), available at http://www.nxp.com. The BMC050 supports I²C standard mode and

fast mode, only 7-bit address mode is supported.

The default I²C address of the BMC050‟s accelerometer part is 0011000b (0x18). It is used if

the SDO pin is pulled to “GND”. The alternative address 0011001b (0x19) is selected by pulling

the SDO pin to “VDDIO”.

The default I²C address of the BMC050‟s magnetometer part is 0x10. The five MSB are

hardwired to “00100”. In order to prevent bus conflicts bit0 can be inverted by setting „1‟ to SDO,

and the bit 1 can be inverted by setting „1‟ to the CSB line according to below Table:

Table 98: BMC050 I²C addresses

CSB2 pin

SDO pin

Accelerometer

part I²C address

Magnetometer part I²C

address

GND

0x18

0x10

GND

VDDIO

0x19

0x11

VDDIO

GND

0x18

0x12

VDDIO

0x19

0x13

The timing specification for I²C of the BMC050 is given in Table 99:

Table 99: I²C timings.

Parameter

Symbol

Condition

Min

Max

Unit

Clock Frequency

fSCL

400

kHz

SCL Low Period

tLOW

s

SCL High Period

tHIGH

SDA Setup Time

tSUDAT

SDA Hold Time

tHDDAT

Setup Time for a

repeated Start

Condition

tSUSTA

Hold Time for a Start

Condition

tHDSTA

Setup Time for a Stop

Condition

tSUSTO

Time before a new

Transmission can

start

tBUF

fully compliant to the I2C specification”UM10204 I2C-bus specification Rev.03 – 19 June 2007”

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Figure 21 shows the definition of the I²C timings given in Table 99:

Figure 21: I²C timing diagram

The I²C protocol works as follows:

START: Data transmission on the bus begins with a high to low transition on the SDA line while

SCL is held high (start condition (S) indicated by I²C bus master). Once the START signal is

transferred by the master, the bus is considered busy.

STOP: Each data transfer should be terminated by a Stop signal (P) generated by master. The

STOP condition is a low to HIGH transition on SDA line while SCL is held high.

ACK: Each byte of data transferred must be acknowledged. It is indicated by an acknowledge

bit sent by the receiver. The transmitter must release the SDA line (no pull down) during the

acknowledge pulse while the receiver must then pull the SDA line low so that it remains stable

low during the high period of the acknowledge clock cycle.

In the following diagrams these abbreviations are used:

S Start

P Stop

ACKS Acknowledge by slave

ACKM Acknowledge by master

NACKM Not acknowledge by master

RW Read / Write

A START immediately followed by a STOP (without SCK toggling from logic “1” to logic “0”) is

not supported. If such a combination occurs, the STOP is not recognized by the device.

I²C write access:

I²C write access can be used to write a data byte in one sequence.

HDDAT

BUF

LOW

HDSTA

SUST

HIGH

SUDAT

SUST

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The sequence begins with start condition generated by the master, followed by 7 bits slave

address and a write bit (RW = 0). The slave sends an acknowledge bit (ACK = 0) and releases

the bus. Then the master sends the one byte register address. The slave again acknowledges

the transmission and waits for the 8 bits of data which shall be written to the specified register

address. After the slave acknowledges the data byte, the master generates a stop signal and

terminates the writing protocol.

Example of an I²C write access:

Figure 22: Example of an I²C write access

I²C read access:

I²C read access also can be used to read one or multiple data bytes in one sequence.

A read sequence consists of a one-byte I²C write phase followed by the I²C read phase. The

two parts of the transmission must be separated by a repeated start condition (Sr). The I²C write

phase addresses the slave and sends the register address to be read. After slave

acknowledges the transmission, the master generates again a start condition and sends the

slave address together with a read bit (RW = 1). Then the master releases the bus and waits for

the data bytes to be read out from slave. After each data byte the master has to generate an

acknowledge bit (ACK = 0) to enable further data transfer. A NACKM (ACK = 1) from the master

stops the data being transferred from the slave. The slave releases the bus so that the master

can generate a STOP condition and terminate the transmission.

The register address is automatically incremented and, therefore, more than one byte can be

sequentially read out. Once a new data read transmission starts, the start address will be set to

the register address specified in the latest I²C write command. By default the start address is set

at 0x00. In this way repetitive multi-bytes reads from the same starting address are possible.

In order to prevent the I²C slave of the device to lock-up the I²C bus, a watchdog timer (WDT) is

implemented in the accelerometer part of BMC050. The WDT observes internal I²C signals and

resets the I²C interface if the bus is locked-up by the BMC050 accelerometer part. The activity

and the timer period of the WDT can be configured through the bits (0x34) i2c_wdt_en and

(0x34) i2c_wdt_sel.

Writing “1” (“0”) to (0x34) i2c_wdt_en activates (de-activates) the WDT. Writing “0” (“1”) to

(0x34) i2c_wdt_se selects a timer period of 1 ms (50 ms).

Example of an I²C multiple read accesses:

Start RW ACKS ACKS ACKS Stop

0 0 1 1 0 0 0 0 0 0 0 1 0 0 0 0 X X X X X X X X

Slave Adress

Control byte

Data byte

Data (0x09)

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Note: Specifications within this document are subject to change without notice. Not intended for publication.

Figure 23: Example of an I²C multiple read access

Start RW ACKS

dummy

ACKS Stop

00110000 X0000010

Start RW ACKS ACKM

ACKM

0 0 1 1 0 0 0 1 X X X X X X X X X X X X X X X X …

ACKM

…XXXXXXXX XXXXXXXX …

ACKM NACK Stop

…XXXXXXXX XXXXXXXX

Data byte

Read Data (0x04)

Read Data (0x05)

Data byte

Read Data (0x06)

Read Data (0x07)

Slave Adress

Read Data (0x03)

Read Data (0x02)

Control byte

Data byte

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Note: Specifications within this document are subject to change without notice. Not intended for publication.

8. Pin-out and connection diagram

8.1 Pin-out

Figure 24: Pin-out top view Figure 25: Pin-out bottom view

The arrows indicate the pin1 marking.

TOP VIEW

(pads not visible)

141516 13 12

87654

10 BOTTOM VIEW

(pads visible)

14 15 161312

8 7 6 5 4

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Note: Specifications within this document are subject to change without notice. Not intended for publication.

Table 100: Pin description

Name

I/O Type

Sensor

Description

Connect to

SPI 4W

SPI 3W

I²C

INT2

Out

Acc

Interrupt output #2

INT2 input or DNC if unused

PS1

Acc

Protocol select #1

GND

VDDIO

PS2

Mag

Protocol select #2

GND

VDDIO

INT3

Out

Mag

Interrupt output #3

INT3 input or DNC if unused

CSB17

Acc

Chip Select #1

CSB1

NC (float) or

VDDIO

CSB27

Mag

Chip Select #2

CSB2

GND for

default

address

GND

Supply

Mag+Ac

Ground

GND

Supply

Mag+Ac

Ground

GND

DRDY

Out

Mag

Data ready

DRDY input or DNC if unused

SDO

Out

Mag+Ac

SPI: Data out

SDO /

MISO

DNC

(float)

GND for

default

address

SDI

In/Out

Mag+Ac

SPI: Data in, I²C:

Data

SDI / MOSI

SDA

GND

Supply

Mag+Ac

Ground

GND

VDD

Supply

Mag+Ac

Supply voltage

VDD

VDDIO

Supply

Mag+Ac

I/O voltage

VDDIO

SCK

Mag+Ac

Serial clock

SCK

SCL

INT1

Out

Acc

Interrupt output #1

INT 1 input or DNC if unused

Note: CSB1 and CSB2 must be operated separately and cannot be tied together.

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8.2 Connection diagram 4-wire SPI

Figure 26: 4-wire SPI connection diagram

Note: the recommended value for C1, C2 is 100 nF. CSB1 and CSB2 must be operated

separately.

TOP VIEW

(pads not visible)

141516 13 12

87654

PS1

PS2

INT2

INT3

CSB1

CSB2

DRDY

SDO

SDI

SCK

INT1

VDDIO VDD

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8.3 Connection diagram 3-wire SPI

Figure 27: 3-wire SPI connection diagram

Note: the recommended value for C1, C2 is 100 nF. CSB1 and CSB2 must be operated

separately.

TOP VIEW

(pads not visible)

141516 13 12

87654

PS1

PS2

INT2

INT3

CSB1

CSB2

DRDY

SDI

SCK

INT1

VDDIO VDD

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Note: Specifications within this document are subject to change without notice. Not intended for publication.

8.4 Connection diagram I2C

Figure 28: I²C connection diagram

Note: the recommended value for C1, C2 is 100 nF.

TOP VIEW

(pads not visible)

141516 13 12

87654

PS1

PS2

INT2

INT3

SDA

SCK

INT1

DRDY

VDDIO VDD

VDDIO

SDO mag & accel

address bit 0

default

mag & accel

address bit 0

inverted

VDDIO

magnetic

address bit 1

default

magnetic

address bit 1

inverted

CSB2

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Note: Specifications within this document are subject to change without notice. Not intended for publication.

9. Package

9.1 Outline dimensions

The sensor housing is a standard LGA 3x3 16-lead package. Its dimensions are the following:

Figure 29: Package outline dimensions

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9.2 Sensing axes orientation

The magnetic and acceleration sensing axes of the BMC050 are matching.

If the sensor is accelerated in the indicated directions, the corresponding channel will deliver a

positive acceleration signal (dynamic acceleration). If the sensor is at rest and the force of

gravity is acting along the indicated directions, the output of the corresponding channel will be

negative (static acceleration). If a positive magnetic field is applied in the indicated directions,

the corresponding channel will deliver a positive acceleration signal.

Example: If the sensor is at rest or at uniform motion in a gravitational and magnetic field

according to the figure given below, the output signals are

 0 g for the X acceleration channel, 0 µT for the X magnetic channel

 0 g for the Y acceleration channel, 0 µT for the Y magnetic channel

 +1 g for the Z acceleration channel, -|B| for the Z magnetic channel

Figure 30: Orientation of sensing axes (acceleration and magnetic)

Please note that the planet‟s north pole is a magnetic south pole. This means that when the

BMC050‟s X axis points towards the north pole, the measured field will be negative.

The following table lists all corresponding output signals on X, Y, and Z while the sensor is at

rest or at uniform motion in a gravity field under assumption of a ±2g range setting and a top

down gravity and magnetic vector as shown above.

Table 101: Output signals depending on sensor orientation

Sensor Orientation

(gravity vector  =

acceleration vector ,

magnetic vector )

Output Signal X

0g / 0LSB

0 µT

+1g /

256LSB

-|B| µT

0g / 0LSB

0 µT

-1g / -

256LSB

+|B| µT

0g / 0LSB

0 µT

0g / 0LSB

0 µT

Output Signal Y

-1g / -

256LSB

+|B| µT

0g / 0LSB

0 µT

+1g /

256LSB

-|B| µT

0g / 0LSB

0 µT

0g / 0LSB

0 µT

0g / 0LSB

0 µT

Output Signal Z

0g / 0LSB

0 µT

0g / 0LSB

0 µT

0g / 0LSB

0 µT

0g / 0LSB

0 µT

+1g /

256LSB

-|B| µT

-1g / -

256LSB

+|B| µT

upright

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Note: Specifications within this document are subject to change without notice. Not intended for publication.

9.3 Android axes orientation

The Android coordinate system is shown in Figure 31. The origin is in the lower-left corner with

respect to the screen, with the X axis horizontal and pointing right, the Y axis vertical and

pointing up and the Z axis pointing outside the front face of the screen. In this system,

coordinates behind the screen have negative Z values.

Figure 31: Android coordinate system

Attitude terms are defined in the following way (see Figure 32):

 Heading / Azimuth – angle between the magnetic north direction and the Y axis, around

the Z axis (0° to 360°). 0° = North, 90° = East, 180° = South, 270° = West.

 Pitch – rotation around X axis (-180° to 180°), with positive values when the z-axis

moves toward the y-axis.

 Roll – rotation around Y axis (-90° to 90°), with positive values when the x-axis moves

toward the z-axis.

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Figure 32: Heading, pitch and roll in Android coordinate frame

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third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.

Note: Specifications within this document are subject to change without notice. Not intended for publication.

9.4 Landing pattern recommendation

For the design of the landing pattern, we recommend the following dimensioning:

Figure 33: Landing patterns relative to the device pins, dimensions are in mm

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Note: Specifications within this document are subject to change without notice. Not intended for publication.

9.5 Marking

9.5.1 Mass production devices

Table 102: Marking of mass production samples

Labeling

Name

Symbol

Remark

Product number

124

Sub-Con ID

Packaging sub-contractor identifier,

coded alphanumerically

Date code

YWW

Y: year, numerically coded:

9 = 2009, 0 = 2010, 1 = 2011, ...

WW: Calendar week, numerical code

Lot counter

CCC

Numerical counter

Pin 1 identifier



9.5.2 Engineering samples

Table 103: Marking of engineering samples

Labeling

Name

Symbol

Remark

Product number

050E

BMC050 Engineering sample

Sub-Con ID

Packaging sub-contractor identifier,

coded alphanumerically

Date code

YWW

Y: year, numerically coded:

9 = 2009, 0 = 2010, 1 = 2011, ...

WW: Calendar week, numerical code

Sample status

x = Numerical counter

Pin 1 identifier



050E

AYWW



124

AYWW

CCC



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third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.

Note: Specifications within this document are subject to change without notice. Not intended for publication.

9.6 Soldering guidelines

The moisture sensitivity level of the BMC050 sensors corresponds to JEDEC Level 1, see also:

 IPC/JEDEC J-STD-020C "Joint Industry Standard: Moisture/Reflow Sensitivity

Classification for non-hermetic Solid State Surface Mount Devices"

 IPC/JEDEC J-STD-033A "Joint Industry Standard: Handling, Packing, Shipping and Use of

Moisture/Reflow Sensitive Surface Mount Devices".

The sensor fulfils the lead-free soldering requirements of the above-mentioned IPC/JEDEC

standard, i.e. reflow soldering with a peak temperature up to 260°C.

Figure 34: Soldering profile

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9.7 Handling instructions

Micromechanical sensors are designed to sense acceleration with high accuracy even at low

amplitudes and contain highly sensitive structures inside the sensor element. The MEMS sensor

can tolerate mechanical shocks up to several thousand g. However, these limits might be

exceeded in conditions with extreme shock loads such as e.g. hammer blow on or next to the

sensor, dropping of the sensor onto hard surfaces etc.

We recommend avoiding g-forces beyond the specified limits during transport, handling and

mounting of the sensors in a defined and qualified installation process.

This device has built-in protections against high electrostatic discharges or electric fields (e.g.

2kV HBM); however, anti-static precautions should be taken as for any other CMOS component.

Unless otherwise specified, proper operation can only occur when all terminal voltages are kept

within the supply voltage range. Unused inputs must always be tied to a defined logic voltage

level.

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Note: Specifications within this document are subject to change without notice. Not intended for publication.

9.8 Tape and reel specification

9.8.1 Tape and reel dimensions

The following picture describes the dimensions of the tape used for shipping the BMC050

sensor device. The material of the tape is made of conductive polystyrene (IV).

Figure 35: Tape and reel dimensions in mm

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Note: Specifications within this document are subject to change without notice. Not intended for publication.

9.8.2 Orientation within the reel

Figure 36: Orientation of the BMC050 devices relative to the tape

124

AYWW

CCC



124

AYWW

CCC



124

AYWW

CCC



124

AYWW

CCC



124

AYWW

CCC



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Note: Specifications within this document are subject to change without notice. Not intended for publication.

9.9 Environmental safety

The BMC050 sensor meets the requirements of the EC restriction of hazardous substances

(RoHS) directive, see also:

Directive 2002/95/EC of the European Parliament and of the Council of 27 January 2003

on the restriction of the use of certain hazardous substances in electrical and electronic

equipment.

9.9.1 Halogen content

Results of chemical analysis indicate that the BMC050 contains less than 900ppm (by weight) of

Fluorine, Chlorine, Iodine and Bromine. Therefore the BMC050 can be regarded as halogen-

free. For more details on the analysis results please contact your Bosch Sensortec

representative.

9.9.2 Internal package structure

Within the scope of Bosch Sensortec‟s ambition to improve its products and secure the mass

product supply, Bosch Sensortec qualifies additional sources (e.g. 2nd source) for the LGA

package of the BMC050.

While Bosch Sensortec took care that all of the technical packages parameters are described

above are 100% identical for all sources, there can be differences in the chemical content and

the internal structural between the different package sources.

However, as secured by the extensive product qualification process of Bosch Sensortec, this

has no impact to the usage or to the quality of the BMC050 product.

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Note: Specifications within this document are subject to change without notice. Not intended for publication.

10. Legal disclaimer

10.1 Engineering samples

Engineering Samples are marked with an asterisk (*) or (e) or (E). Samples may vary from the

valid technical specifications of the product series contained in this data sheet. They are

therefore not intended or fit for resale to third parties or for use in end products. Their sole

purpose is internal client testing. The testing of an engineering sample may in no way replace

the testing of a product series. Bosch Sensortec assumes no liability for the use of engineering

samples. The Purchaser shall indemnify Bosch Sensortec from all claims arising from the use of

engineering samples.

10.2 Product use

Bosch Sensortec products are developed for the consumer goods industry. They may only be

used within the parameters of this product data sheet. They are not fit for use in life-sustaining

or security sensitive systems. Security sensitive systems are those for which a malfunction is

expected to lead to bodily harm or significant property damage. In addition, they are not fit for

use in products which interact with motor vehicle systems.

The resale and/or use of products are at the purchaser‟s own risk and his own responsibility.

The examination of fitness for the intended use is the sole responsibility of the Purchaser.

The purchaser shall indemnify Bosch Sensortec from all third party claims arising from any

product use not covered by the parameters of this product data sheet or not approved by Bosch

Sensortec and reimburse Bosch Sensortec for all costs in connection with such claims.

The purchaser must monitor the market for the purchased products, particularly with regard to

product safety, and inform Bosch Sensortec without delay of all security relevant incidents.

10.3 Application examples and hints

With respect to any examples or hints given herein, any typical values stated herein and/or any

information regarding the application of the device, Bosch Sensortec hereby disclaims any and

all warranties and liabilities of any kind, including without limitation warranties of non-

infringement of intellectual property rights or copyrights of any third party. The information given

in this document shall in no event be regarded as a guarantee of conditions or characteristics.

They are provided for illustrative purposes only and no evaluation regarding infringement of

intellectual property rights or copyrights or regarding functionality, performance or error has

been made.

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Note: Specifications within this document are subject to change without notice. Not intended for publication.

11. Document history and modification

Rev. No

Chapter

Description of modification/changes

Date

0.1

Document creation

2010-08-12

0.3

New revision

2011-03-07

0.4

New revision

2011-03-29

0.5

New revision

2011-06-15

0.6

New revision

2011-07-28

0.7

New revision

2011-10-13

1.0

Not longer under preliminary status

2011-10-28

Bosch Sensortec GmbH

Gerhard-Kindler-Strasse 8

72770 Reutlingen / Germany

contact@bosch-sensortec.com

www.bosch-sensortec.com

Modifications reserved | Printed in Germany

Specifications subject to change without notice

Document number: BST-BMC050-DS000-10

Revision_1.0_102011

Mouser Electronics

Authorized Distributor

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