SCA3000 Series Datasheet by Murata Electronics

View All Related Products | Download PDF Datasheet
VTI ‘9 TECHNOLOGIES
Doc.Nr. 8257300A.07
Product Family Specification
SCA3000 Series
3-axis accelerometer
VTI ® TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 2/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
TABLE OF CONTENTS
1 General Description ........................................................................................................... 5
1.1 Introduction................................................................................................................................5
1.2 Functional Description..............................................................................................................5
1.2.1 Sensing element..................................................................................................................5
1.2.2 Interface IC...........................................................................................................................5
1.2.3 Factory calibration ..............................................................................................................6
1.2.4 Supported features .............................................................................................................6
1.2.5 Operation modes.................................................................................................................6
1.2.5.1 Measurement................................................................................................................................6
1.2.5.2 Motion Detection..........................................................................................................................6
1.2.6 Free-Fall Detection..............................................................................................................6
1.2.7 Interrupt................................................................................................................................7
1.2.8 Temperature output ............................................................................................................7
1.2.9 Output ring buffer................................................................................................................7
2 Reset and power up, Operation Modes, HW functions and Clock................................. 7
2.1 Reset and power up...................................................................................................................7
2.2 Measurement Mode ...................................................................................................................7
2.2.1 Description...........................................................................................................................7
2.2.1.1 Bypass measurement mode.......................................................................................................8
2.2.1.2 Narrow band measurement mode..............................................................................................8
2.2.1.3 Wide band measurement mode .................................................................................................8
2.2.2 Usage....................................................................................................................................8
2.2.2.1 Overflow condition ......................................................................................................................8
2.3 Motion Detection Mode .............................................................................................................9
2.3.1 Description...........................................................................................................................9
2.3.2 Usage..................................................................................................................................10
2.3.3 Examples............................................................................................................................10
2.4 Free-Fall Detection...................................................................................................................11
2.4.1 Description.........................................................................................................................11
2.4.2 Usage..................................................................................................................................11
2.4.3 Example..............................................................................................................................11
2.5 Ring Buffer ...............................................................................................................................12
2.5.1 Description.........................................................................................................................12
2.5.2 Usage..................................................................................................................................12
2.5.2.1 Overflow condition ....................................................................................................................12
2.5.3 Examples............................................................................................................................13
2.6 Temperature measurement.....................................................................................................13
2.6.1 Usage..................................................................................................................................13
2.7 Interrupt function (INT-pin) .....................................................................................................13
2.7.1 Usage..................................................................................................................................13
2.8 Clock .........................................................................................................................................14
VTI ® TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 3/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
3 Addressing Space............................................................................................................ 15
3.1 Register Description................................................................................................................15
3.2 Non-volatile memory ...............................................................................................................16
3.3 Output Registers......................................................................................................................16
3.4 Configuration Registers..........................................................................................................19
4 Serial Interfaces ...............................................................................................................24
4.1 SPI Interface .............................................................................................................................24
4.1.1 SPI frame format................................................................................................................24
4.1.2 SPI bus error conditioning ...............................................................................................25
4.1.3 Examples of SPI communication.....................................................................................25
4.1.3.1 Example of register read...........................................................................................................25
4.1.3.2 Example of decremented register read ...................................................................................26
4.1.3.3 Example of ring buffer read......................................................................................................26
4.2 I2C Interface..............................................................................................................................27
4.2.1 I2C frame format.................................................................................................................27
4.2.1.1 I2C write mode............................................................................................................................27
4.2.1.2 I2C read mode.............................................................................................................................27
4.2.1.3 Decremented register read .......................................................................................................27
4.2.2 Examples of I2C communication......................................................................................28
5 Electrical Characteristics ................................................................................................ 29
5.1 Absolute maximum ratings.....................................................................................................29
5.2 Power Supply ...........................................................................................................................29
5.3 Digital I/O Specification...........................................................................................................29
5.3.1 Digital I/O DC characteristics...........................................................................................29
5.3.2 Digital I/O level shifter.......................................................................................................29
5.3.3 SPI AC characteristics......................................................................................................30
5.3.4 I2C AC characteristics.......................................................................................................31
6 Package Characteristics.................................................................................................. 31
6.1 Dimensions...............................................................................................................................31
7 Application information................................................................................................... 32
7.1 Pin Description.........................................................................................................................32
7.2 Recommended circuit diagram ..............................................................................................32
7.3 Recommended PWB layout ....................................................................................................33
7.4 Assembly instructions ............................................................................................................35
7.5 Tape and reel specifications...................................................................................................35
8 Data sheet references...................................................................................................... 36
VTI ® TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 4/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
8.1 Offset.........................................................................................................................................36
8.1.1 Offset calibration error .....................................................................................................36
8.1.2 Offset temperature error...................................................................................................36
8.2 Sensitivity.................................................................................................................................37
8.2.1 Sensitivity calibration error..............................................................................................37
8.2.2 Sensitivity temperature error ...........................................................................................37
8.3 Linearity....................................................................................................................................38
8.4 Noise .........................................................................................................................................39
8.5 Bandwidth.................................................................................................................................39
8.6 Cross-axis sensitivity..............................................................................................................39
8.7 Turn-on time.............................................................................................................................40
9 Order Information............................................................................................................. 41
10 Document Change Control.............................................................................................. 42
11 Contact Information ......................................................................................................... 43
VTI 9 TECHNOLOGIES 7 Lqupass 7 Denmamn 7 Cumdma‘e SCK’SCL E Fmer Mappmg , E (EN DE7 and sm muse/5m 17 7 7 MUX 7 Lqupass 7 Denmamn Cahbvam" 5 ‘ 3 Fmar ‘29 MOSI w ‘ 7 Lqupass 7 Denmauan 7 959 i Fmer Oscmam Relevance Nam Mumn FveeiaH ng Camml INT 3 Vo‘aule de‘eclor de‘ecmr Buflev s clack Mammy \NT VTI Techno‘ogies Dy www.vh Ii DDc.Nr. 5257300A.u7 5/43 Rev,A.O7
SCA3000 Series
VTI Technologies Oy 5/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
1 General Description
1.1 Introduction
SCA3000 is a three axis accelerometer family targeted for products requiring high performance
with low power consumption. It consists of a 3D-MEMS sensing element and a signal conditioning
ASIC packaged into a plastic Molded Interconnection Device package (MID).
A block diagram of the SCA3000 product family is presented in Figure 1 below.
INT
DE-
MUX
1:3
Low-pass
Filter
Low-pass
Filter
Low-pass
Filter
Decimation
Decimation
Decimation
Coordinate
Mapping
and
Calibration
Oscillator
&
clock
Motion
detector Free fall
detector
Reference
SPI
&
I2C
i/f
Control
&
INT
SCK/SCL
MISO/SDA
MOSI
CSB
Ring
Buffer
C/V
Analog
calibration
&
ADC
Non-
Volatile
Memory
Temperature
sensor
Figure 1. SCA3000 Block Diagram.
This document, no. 8257300, describes the product specification (e.g. operation modes, user
accessible registers, electrical properties and application information) for the SCA3000 family. The
specification for an individual sensor is available in the corresponding data sheet.
1.2 Functional Description
1.2.1 Sensing element
The sensing element is manufactured using the proprietary bulk 3D-MEMS process, which enables
robust, stable and low noise & power capacitive sensors.
The sensing element consists of three acceleration sensitive masses. Acceleration will cause a
capacitance change that will be then converted into a voltage change in the signal conditioning
ASIC. Due to its mechanical construction, the element's measurement coordinates are rotated 45°
compared to the conventional orthogonal X,Y,Z coordinate system.
1.2.2 Interface IC
The sensing element is interfaced via a capacitance-to-voltage (CV) converter. Following
calibration in the analog domain, the signal is converted by a successive approximation type of
analog-to-digital converter (ADC). The ADC's signal is de-multiplexed into three signal processing
channels where it is low-pass filtered and decimated. After that, the signals are mapped into
orthogonal coordinates (X-Y-Z) and transferred to the output registers. Depending on the product,
the SCA3000 sensor supports either a fully digital serial SPI or I2C interface. In normal
measurement mode, acceleration data can be read via the serial bus. Other supported features are
a separate motion detection mode and parallel free-fall detection. In these modes, the sensor will
generate an interrupt when a pre-defined condition has been met.
The SCA3000 includes an internal oscillator, reference and non-volatile memory that enable the
sensor's autonomous operation within a system. The temperature sensor is used in some product
applications to enhance the temperature stability. In that case, temperature information can also be
read out from the device.
VTI ’9 TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 6/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
1.2.3 Factory calibration
Sensors are factory calibrated and the trimmed parameters are gain, offset and the frequency of
the internal oscillator. Calibration parameters will be read automatically from the internal non-
volatile memory during sensor startup.
1.2.4 Supported features
Features supported by individual SCA3000 products are listed in Table 1 below.
Table 1. SCA3000 devices’ summary.
Features SCA3000-D01 (SPI) /
SCA3000-D02 (I2C)
SCA3000-E01 (SPI) /
SCA3000-E02 (I2C) SCA3000-E04 SCA3000-E05
Supply
voltage 2.35 V – 3.6 V 2.35 V – 3.6 V 2.35 V – 3.6 V 2.35 V – 3.6 V
I/O voltage 1.7 V – 3.6 V 1.7 V – 3.6 V 1.7 V – 3.6 V 1.7 V – 3.6 V
Measuring
range ±2 g ±3 g ±6 g ±18 g
Resolution 0.75mg / 0.04° 1mg / 0.06° 2mg / 0.11° 6.25mg / 0.36°
Sensitivity 1333 counts/g 1000 counts/g 500 counts/g 160 counts/g
Output
buffer
User enabled,
64 sampl./axis
User enabled,
64 sampl./axis
User enabled,
64 sampl./axis
User enabled,
64 sampl./axis
Motion
detection User enabled User enabled User enabled User enabled
Free fall
detection User enabled User enabled User enabled User enabled
Interface SPI max 1.6 MHz (-D01) /
I2C fast mode (-D02)
SPI max 325 kHz (-E01) /
I2C std mode (-E02)
SPI max 325 kHz SPI max 325 kHz
Temperatu
re output Yes No No No
Clock Internal Internal Internal Internal
1.2.5 Operation modes
1.2.5.1 Measurement
The SCA3000 is in normal measurement mode by default after start up. The sensor offers
acceleration information via the SPI or I2C when the master requires it. The master can acquire one
axis acceleration or all three axis acceleration depending on the application. Measurement
resolution depends on the product type (see Table 1).
1.2.5.2 Motion Detection
Motion Detection (MD) mode is intended to be used to save system level power consumption. In
this mode, the SCA3000 activates the interrupt via the INT-pin when motion is detected. Sensitivity
levels can be configured via the SPI or I2C bus for each axis. Moreover, the detection condition can
be defined using sensitivity directions with AND / OR / mux logic. Once the interrupt has happened,
the detected direction can be read out from the corresponding status register.
Normal acceleration information is not available in MD mode.
1.2.6 Free-Fall Detection
Free-Fall Detection (FFD) is intended to be used to save system resources. This feature activates
the interrupt via the INT-pin when free-fall is detected. The minimum detectable distance depends
on the individual product. Normal acceleration information is available when the FFD is enabled.
VTI ® TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 7/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
1.2.7 Interrupt
The SCA3000 has a dedicated output pin (INT) to be used as the interrupt for the master controller.
Interrupt conditions can be activated and deactivated via the SPI or I2C bus. Once the interrupt has
happened, the interrupt source can be read out from the corresponding status register.
1.2.8 Temperature output
Some SCA3000 products provide 9-bit temperature information via the serial interface. See Table 1
for detailed product information.
1.2.9 Output ring buffer
In those applications where real time acceleration information is not needed, the ring buffer
memory can be used to buffer acceleration data. This will release µC resources for other tasks or
for example, to offer a power saving mode while SCA3000 samples acceleration data into its buffer
memory.
Acceleration data is sampled at a constant sample rate by the sensor. The buffer is a FIFO type
(First In First Out) where the oldest data is shifted out first. It has separate read and write address
pointers, so it can be read and written simultaneously. If the buffer overflows, the oldest data is lost
and the new data replaces the oldest samples.
Ring buffer logic can be configured to give an interrupt when the buffer is ½ or ¾ full. The entire
ring buffer content can be read by one read sequence.
2 Reset and power up, Operation Modes, HW functions and Clock
2.1 Reset and power up
The SCA3000 has an external active low reset pin. Power supplies must be within the specified
range before the reset can be released.
After releasing the reset, the SCA3000 will read configuration and calibration data from the non-
volatile memory to volatile registers. Then the SCA3000 will make a check sum calculation to the
read memory content. The STATUS register's CSME-bit="0" shows successful memory read
operation.
2.2 Measurement Mode
2.2.1 Description
The SCA3000 enters the measurement mode by default after power-on and the CV-converter will
start to feed data to the signal channel (Figure 1). Data will be reliable in the output registers after
the product specific turn-on time.
The SCA3000 can also be set to optional measurement modes. See component specific data
sheets for detailed functional parameters in all measurement modes. All available measurement
modes for the SCA3000 are described in Table 2 below.
VTI (9 TECHNOLOGIES m |
SCA3000 Series
VTI Technologies Oy 8/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
Table 2. Available measurement modes for SCA3000.
Available measurement
modes SCA3000-D01
SCA3000-D02 SCA3000-E01
SCA3000-E02 SCA3000-E04 SCA3000-E05
Default after power-on
or reset
Measurement
mode
Measurement
mode
Measurement
mode
Measurement
mode
Optional measurement
mode 1
Bypass
measurement
mode
Narrow band
measurement
mode
Narrow band
measurement
mode
Narrow band
measurement
mode
Optional measurement
mode 2 Not available Not available
Wide band
measurement
mode
Wide band
measurement
mode
2.2.1.1 Bypass measurement mode
In bypass measurement mode, the signal bandwidth of the SCA3000 is extended by bypassing the
low-pass filter in signal channel. As a result of a wider measurement bandwidth, the noise level is
higher.
2.2.1.2 Narrow band measurement mode
In narrow band measurement mode, the signal bandwidth of the SCA3000 is reduced by increasing
low-pass filtering in signal channel. In addition, the output data rate is halved due to decimation. As
a result of a narrower signal bandwidth, the noise level is lower.
2.2.1.3 Wide band measurement mode
In wide band measurement mode, the SCA3000 signal channel low-pass filtering pass band is
widened. As a result of a wider measurement bandwidth, the noise level is higher.
2.2.2 Usage
The optional measurement modes can be enabled by setting the bits called MODE_BITS in MODE
register to "010" or "001". See section 3.4 for MODE register details.
Acceleration data can be read from data output registers X_LSB, X_MSB, Y_LSB, Y_MSB, Z_LSB
and Z_MSB in all measurement modes. Each of these registers can be read one by one or using
the decrement register read, which is described in section 4.1.3.2 for SPI and 4.2.1.3 for I2C
interface. See section 3.3 for output register details.
2.2.2.1 Overflow condition
Since acceleration data registers have no limiter, the possible overflow needs to be detected using
bits [B7, B6, B5]. If bits [B7, B6, B5] are ‘011’ or ‘100’, data overflow has occurred (see Table 3).
This applies for all acceleration output registers (X_LSB … Z_MSB and BUF_DATA).
Table 3. Overflow bit patterns in acceleration data registers (X_LSB … Z_MSB and BUF_DATA).
Byte MSB byte LSB byte
Bit number
Acceleration data bit B7
Sign B6
d11 B5
d10 B4
d9 B3
d8 B2
d7 B1
d6 B0
d5 B7
d4 B6
d3 B5
d2 B4
d1 B3
d0 B2:B0
Data overflow on
positive acceleration 0 1 1 x x x x x x x x x x xxx
Data overflow on
negative
acceleration 1 0 0 x x x x x x x x x x xxx
x = ignore
In case of overflow, the output register value must be discarded. When an overflow is detected, the
bit pattern ‘0101 1111 1111 1xxx’ is used for positive accelerations and ‘1010 0000 0000 0xxx’ for
VTI ® TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 9/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
negative accelerations until a valid acceleration value is read. In Table 4 the maximum and
minimum acceleration register values that are in measuring range (for registers X_LSB … Z_MSB)
for SCA3000-D0x and SCA3000-E0x are presented.
Table 4. Maximum and minimum values in the SCA3000 measuring range.
SCA3000-D01
SCA3000-D02 SCA3000-E01
SCA3000-E02 SCA3000-E04 SCA3000-E05
First positive
acceleration value
out of range
[mg]
dec
bin
-
3072
0110 0000 0000 0xxx
-
3072
0110 0000 0000 0xxx
-
3072
0110 0000 0000 0xxx
-
3072
0110 0000 0000 0xxx
Maximum positive
acceleration value
in range
[mg]
dec
bin
2303.25 mg
3071
0101 1111 1111 1xxx
3071 mg
3071
0101 1111 1111 1xxx
6142 mg
3071
0101 1111 1111 1xxx
19193.75 mg
3071
0101 1111 1111 1xxx
Minimum negative
acceleration value
in range
[mg]
dec
bin
-2304 mg
-3072
1010 0000 0000 0xxx
-3072 mg
-3072
1010 0000 0000 0xxx
-6144 mg
-3072
1010 0000 0000 0xxx
-19200 mg
-3072
1010 0000 0000 0xxx
First negative
acceleration value
out of range
[mg]
dec
bin
-
-3073
1001 1111 1111 1xxx
-
-3073
1001 1111 1111 1xxx
-
-3073
1001 1111 1111 1xxx
-
-3073
1001 1111 1111 1xxx
2.3 Motion Detection Mode
2.3.1 Description
In MD mode, the ADC's data is not fed to the signal processing channel shown in Figure 1 but to
the MD block. It consists of a digital band-pass filter (BPF), threshold level programmable digital
comparator and a configurable trigger function.
BPF's -3 dB low-pass frequency is 25 Hz …60 Hz and -3 dB high-pass frequency is
0.05 Hz …1 Hz. See Figure 2 below.
Band Pass Filter's Response
for reference only
-20
-15
-10
-5
0
5
0.01 0.1 1 10 100 1000
Freq [Hz]
Attenuation [dB]
Lower limit
Upper limit
Figure 2. The MD band-pass filter's frequency response.
EEEEEEEEEEEE
SCA3000 Series
VTI Technologies Oy 10/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
The absolute value of programmable Threshold Level (TL) is 0 < |TL| < FS g (FS is sensor full
scale measuring range). NOTE: Due to power consumption optimization, the step size between
each step and axis is not the same, see section 3.4 for threshold level details.
The triggering condition can be defined using OR/AND logic:
1. Any sensing direction can be configured to trigger the interrupt (OR condition).
2. Any sensing direction can be configured to be required to trigger the interrupt (AND condition).
+TL
Acceleration exceeds
the threshold level
due to motion
-TL
Acceleration
X, Y or Z
T1 T2 T3 T4 T5 T6 T7 T8 Time
T1 T2 T3 T4 T5 T6 T7 T8 Time
INT output
"1"
"0"
Figure 3. Motion detector operation.
2.3.2 Usage
The MD mode can be enabled by setting the MODE bits in the MODE register to "011". The trigger
condition can be defined by setting REQ_Z, REQ_Y, REQ_X, EN_Z, EN_Y and EN_X bits in
MD_CTRL register and Z_TH, Y_TH and Z_TH bits in MD_Z_TH, MD_Y_TH and MD_X_TH
registers, respectively. See section 3.4 for the configuration register and section 2.7 for the
interrupt functionality details.
In MD mode, acceleration data is not available in registers X_LSB, X_MSB, Y_LSB, Y_MSB,
Z_LSB, Z_MSB and BUF_DATA.
2.3.3 Examples
A simple example of motion detection usage:
1. Write "00000011" (03h) into the MODE register (enable motion detection mode,
MODE_BITS = '011').
2. Acceleration data is not available when the SCA3000 is in motion detection mode.
3. The INT-pin is activated when motion is detected, see section 2.7 for detailed INT-pin
information.
In the next example, the motion detector is configured to give an interrupt on motion only in the X-
OR Y-axis direction:
1. Write "00000011" (03h) into MODE register (enable motion detection mode,
MODE_BITS = '011')
2. Write "00000000" (00h) into UNLOCK register
3. Write "01010000" (50h) into UNLOCK register
4. Write "10100000" (A0h) into UNLOCK register
5. Write "00000010" (02h) into CTRL_SEL register (to select indirect MD_CTRL register)
Unlock sequence for register lock
6. Write "00000011" (03h) into CTRL_DATA register (this data is written into MD_CTRL
register, enable trigger on Y-channel, EN_Y = '1', enable trigger on X-channel, EN_X = '1')
VTI ‘9 TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 11/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
7. Acceleration data is not available when the SCA3000 is in motion detection mode
8. The INT-pin is activated when motion is detected in the X- or Y-axis direction (Z-axis
direction is ignored), see section 2.7 for detailed INT-pin information.
2.4 Free-Fall Detection
2.4.1 Description
During free-fall in the gravitation field, all 3 orthogonal acceleration components are ideally equal to
zero. Due to practical non-idealities, detection must be done using Threshold Level (TL) greater
than 0.
When enabled, the Free-Fall Detection (FFD) will monitor 8 MSB's of the measured acceleration in
the X, Y and Z directions. If the measured acceleration stays within the TL longer than time TFF
(Figure 4 below), which corresponds approx 25 cm drop distance, the FFD will generate an
interrupt to the INT-pin.
T1 T2 T3 T4 T5 T6 T7 T8
+TL
TFF
-TL
Acceleration
X, Y and Z
Time
T1 T2 T3 T4 T5 T6 T7 T8 Time
INT output
"1"
"0"
Figure 4. Free Fall condition.
2.4.2 Usage
Free-fall detection can be enabled by setting FFD_EN bit in MODE register to "1". See section 3.4
for MODE register details.
Acceleration data is available in registers X_LSB, X_MSB, Y_LSB, Y_MSB, Z_LSB, Z_MSB and
BUF_DATA as in measurement mode. See section 3.3 for output register and section 2.7 for
interrupt functionality details.
2.4.3 Example
A simple example of free-fall detection usage:
1. Write "00010000" (10h) into the MODE register (enable free fall detection, FFD_EN = '1')
2. Acceleration data can be read normally
3. INT-pin is activated when free fall is detected, see section 2.7 for detailed INT-pin
information.
VTI ® TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 12/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
2.5 Ring Buffer
2.5.1 Description
The SCA3000's Ring Buffer is a 192 acceleration data samples long (64 samples of 11 bit three
axis data) internal memory to relax the real-time operation requirements of the host processor. The
following parameters are configurable:
1. Each measurement axis can be individually disabled. If measurement data from e.g. Y-axis
is not needed, available memory can be used for X- and Z-axis data.
2. Buffer data length can be changed from 11 to 8 bits. In 8-bit mode, data can be read out
using shorter read sequence.
3. Ring buffer's input sample rate can be the same as the sensor's data rate or divided by 2
or 4. When the divider is e.g. 2, only every 2nd acceleration data will be stored.
4. The Interrupt condition, when enabled, can be selected between two: interrupt in INT-pin
occurs when the buffer is 50% or 75% full.
2.5.2 Usage
The ring buffer can be enabled by setting BUF_EN bit in MODE register to "1". After enabling the
buffer, acceleration data can be read from BUF_DATA register using decrement register read,
which is described in section 4.1.3.2 for SPI and 4.2.1.3 for I2C interface.
Each measurement axis can be individually disabled by setting corresponding bits in BUF_X_EN,
BUF_Y_EN and BUF_Z_EN in OUT_CTRL register to "0".
Output data length can be changed from 11 bits to 8 bits by setting bit BUF_8BIT in MODE register
to "1". See section 3.3 for bit level descriptions.
The count of available data samples in output ring buffer can be read from BUF_COUNT register.
Register value is updated only when it is accessed over the SPI or I2C.
Data shift out order is X,Y,Z. In 11 bit mode two bytes must be read to get all 11 bits out. In that
case, the MSB byte is 1st. Examples:
1. 11 bits data length, X&Y&Z axis enabled:
X1_MSB, X1_LSB, Y1_MSB, Y1_LSB, Z1_MSB, Z1_LSB, X2_MSB, X2_LSB, ... latest
Z_LSB
2. 11 bits data length, Y&Z axis enabled:
Y1_MSB, Y1_LSB, Z1_MSB, Z1_LSB, Y2_MSB, Y2_LSB, Z2_MSB, Z2_LSB, Y3_MSB,
Y3_LSB, ..., latest Z_LSB
3. 8 bits data length, all axis enabled:
X1, Y1, Z1, X2, Y2, Z2,..., latest Z
4. 8 bits data length, X&Z axis enabled:
X1, Z1, X2, Z2, X3, Z3, ..., latest Z
5. 8 bits data length, Z axis enabled:
Z1, Z2, Z3, ... , latest Z
See section 2.7 for interrupt functionality details.
Acceleration data is available in X_LSB, X_MSB, Y_LSB, Y_MSB, Z_LSB and Z_MSB when the
ring buffer is enabled.
2.5.2.1 Overflow condition
Overflow is detected from data ring buffer in same way as from the output registers. See section
2.2.2.1 for details.
VTI $9 TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 13/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
2.5.3 Examples
A simple example of output ring buffer usage:
1. Write "10000000" (C0h) into MODE register (enable output ring buffer, BUF_EN = '1')
2. Acceleration data can be read normally
3. INT-pin is activated when buffer is ½ full, see section 2.7 for detailed INT-pin information.
In the next example, the output Ring Buffer is configured to sample only the Z-axis acceleration
data with 8 bit resolution and reduced data rate (only every second sample is stored into output
ring buffer). In addition, the SCA3000 is configured to give an interrupt when the output ring buffer
is ¾ full:
1. Write "11000000" (C0h) into the MODE register (enable output ring buffer, BUF_EN = '1',
set data length to 8 bits, BUF_8BIT = '1')
2. Write "00000000" (00h) into UNLOCK register
3. Write "01010000" (50h) into UNLOCK register
4. Write "10100000" (A0h) into UNLOCK register
5. Write "00001011" (0Bh) into CTRL_SEL register (to select indirect OUT_CTRL register)
Unlock sequence for register lock
6. Write "00000101" (03h) into CTRL_DATA register (this data is written into OUT_CTRL
register, store Z-axis data, BUF_Z_EN = '1', divide data rate by 2, BUF_RATE = '01')
7. Write "10000001" (81h) into INT_MASK register (set buffer interrupt level to ¾ full,
BUF_F_EN = '1', set INT-pin to active high, INT_ACT = '1')
8. Acceleration data can be read normally for all axis and with full resolution. The buffer data
can be read from BUF_DATA register
9. INT-pin is activated when the output ring buffer is ¾ full of Z-axis acceleration data, see
section 2.7 for detailed INT-pin information.
2.6 Temperature measurement
2.6.1 Usage
Nine bit temperature information is available in the TEMP_MSB and TEMP_LSB registers, if the
feature is enabled in the product (see Table 1). The TEMP_MSB register must be read before the
TEMP_LSB register in order to get valid temperature data. Registers are updated with the latest
temperature data when accessed. See section 3.3 for register details.
The temperature registers’ typical output at +23 °C is 256 counts and a 1 °C change in temperature
typically corresponds to a 1.8 LSB change in the SCA3000 temperature output. Temperature
information is converted to [°C] as follows
Equation 1
[]
C
LSB
LSBTemp
CCTemp dec
°
+°=°
8.1
256
23
where Temp[°C] is temperature in Celsius and Tempdec is the temperature from TEMP_MSB and
TEMP_LSB registers in decimal format.
2.7 Interrupt function (INT-pin)
2.7.1 Usage
The Motion Detector and Free Fall Detector will generate an interrupt to INT-pin when the
corresponding function is enabled and the interrupt condition is met. The SCA3000's ring buffer will
generate an interrupt when interrupt functionality has been enabled. Setting BUF_F_EN bit in
INT_MASK register "1" results in interrupt when the register is 75% full. Setting BUF_H_EN bit in
INT_MASK register "1" results in interrupt when the register is 50% full.
Setting INT_ALL bit in INT_MASK register will mask all interrupts.
VTI ® TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 14/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
The interrupt polarity (active high/low) can be configured with INT_MASK register's INT_ACT bit.
Once the interrupt has happened, the INT_STATUS register must be read to acknowledge the
interrupt.
1. If at least one of MD bits in INT_STATUS register is "1", motion has been detected.
2. If FFD bit in INT_STATUS register is "1", free-fall has been detected.
3. If BUF_FULL bit is "1", Ring Buffer is 75% full. Correspondingly, if BUF_HALF is "1", the
Ring Buffer is 50% full.
See section 3.3 for INT_STATUS register details.
2.8 Clock
The SCA3000 has an internal factory trimmed oscillator and clock generator. Internal frequencies
vary product by product.
VTI ‘9 TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 15/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
3 Addressing Space
The SCA3000 register contents and bit definitions are described in more detail in the following
sections.
3.1 Register Description
The SCA3000 addressing space is presented in Table 5 below.
Table 5. List of registers.
Addr. Name Description Mode
(R, W, RW, IA)
Reg.
type Locked
00h REVID ASIC revision ID number R Conf
01h Reserved -
02h STATUS Status register R Conf
03h Reserved -
04h X_LSB X-axis LSB frame R Output
05h X_MSB X-axis MSB frame R Output
06h Y_LSB Y-axis LSB frame R Output
07h Y_MSB Y-axis MSB frame R Output
08h Z_LSB Z-axis LSB frame R Output
09h Z_MSB Z-axis MSB frame R Output
0Ah ... 0Eh Reserved -
0Fh BUF_DATA Ring buffer output register R Output
10h ... 11h Reserved -
12h TEMP_LSB Temperature LSB frame R Output
13h TEMP_MSB Temperature MSB frame R Output
14h MODE Operating mode selection,
control and configuration for:
- mode selection
- output buffer
- free-fall detection
RW Conf
15h BUF_COUNT Count of unread data
samples in output buffer R Output
16h INT_STATUS Interrupt status register:
- output buffer is not full, ½
full or ¾ full
- free-fall detected / not
detected
- information of which axis
triggered motion
R Output
17h I2C_RD_SEL Register address for I2C read
operation RW Conf
18h CTRL_SEL Register address pointer for
indirect control registers RW Conf x
19h
...
1Dh
Reserved -
1Eh UNLOCK Unlock register RW Conf
1Fh ... 20h Reserved -
VTI ‘9 TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 16/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
Addr. Name Description Mode
(R, W, RW, IA)
Reg.
type Locked
21h INT_MASK HW interrupt mask register
(configures the operation of
INT-pin):
- interrupt when output
buffer is ¾ full
(enable / disable)
- interrupt when output
buffer is ½ full
(enable / disable)
- mask all interrupts on
INT-pin (enable / disable)
- INT-pin activity (INT
active low / INT active
high)
RW, NV Conf
22h CTRL_DATA Data to/from register which
address is in CTRL_SEL
(18h) register
RW, NV, IA Conf x
23h ... 3Fh Reserved -
Add. is the register address in hex format.
RW – Read / Write register, R – Read-only register, NV – Register mirrors NV-memory data (NV = non-volatile).
IA – indirect addressing used.
Registers whose read and write access is blocked by register lock is marked in "Locked" column.
3.2 Non-volatile memory
The SCA3000 has an internal non-volatile memory for calibration and configuration data. Memory
content will be programmed during production and is not user configurable. Initial configuration
values can be found in the following section 3.4.
3.3 Output Registers
The SCA3000 output registers (marked with 'Output' in Table 5) contents and bit definitions are
described in this section. Output registers contain information of measured acceleration and
temperature as well as information of the operating state and interrupts of SCA3000.
When reading the output values an MSB register must be read first because MSB register reading
latches the data in to all other acceleration output registers
Address: 04h
Register name: X_LSB, X-axis LSB frame
Bits Mode Initial
Value Name Description
7:0 R 00h DATA X-axis LSB frame
Address: 05h
Register name: X_MSB, X-axis MSB frame
Bits Mode Initial
Value Name Description
7:0 R 00h DATA X-axis MSB frame
Address: 06h
Register name: Y_LSB, Y-axis LSB frame
Bits Mode Initial
Value Name Description
7:0 R 00h DATA Y-axis LSB frame
VTI ’9 TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 17/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
Address: 07h
Register name: Y_MSB, Y-axis MSB frame
Bits Mode Initial
Value Name Description
7:0 R 00h DATA Y-axis MSB frame
Address: 08h
Register name: Z_LSB, Z-axis LSB frame
Bits Mode Initial
Value Name Description
7:0 R 00h DATA Z-axis LSB frame
Address: 09h
Register name: Z_MSB, Z-axis MSB frame
Bits Mode Initial
Value Name Description
7:0 R 00h DATA Z-axis MSB frame
Address: 0Fh
Register name: BUF_DATA, ring buffer output register
Bits Mode Initial
Value Name Description
7:0 R 00h DATA Ring buffer output register
Bit level description for acceleration data from X_LSB ... Z_MSB and BUF_DATA registers is
presented in Table 6 ... Table 9. Acceleration data is presented in 2's complement format. At 0 g
acceleration the output is ideally 00h.
Table 6. Bit level description for acceleration registers of SCA3000-D01 and SCA3000-D02.
Byte MSB byte LSB byte
Bit number
Acceleration [mg] B7
Sign B6
1536 B5
768 B4
384 B3
192 B2
96 B1
48 B0
24 B7
12 B6
6 B5
3 B4
1.5 B3
0.75
B2:B0
xxx
SCA3000-D01,-D02
[X_LSB…Z_MSB] s d11 d10 d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 xxx
SCA3000-D01,-D02
Ring buffer in 11-bit
mode [BUF_DATA] s d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 x x xxx
SCA3000-D01,-D02
Ring buffer in 8-bit
mode [BUF_DATA] s d6 d5 d4 d3 d2 d1 d0 x x x x x xxx
s = sign bit
x = not used bit
Table 7. Bit level description for acceleration registers of SCA3000-E01 and SCA3000-E02.
Byte MSB byte LSB byte
Bit number
Acceleration [mg] B7
Sign B6
2048 B5
1024 B4
512 B3
256 B2
128 B1
64 B0
32 B7
16 B6
8 B5
4 B4
2 B3
1
B2:B0
xxx
SCA3000-E01,-E02
[X_LSB…Z_MSB] s d11 d10 d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 xxx
SCA3000-E01,-E02
Ring buffer in 11-bit
mode [BUF_DATA] s d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 x x xxx
SCA3000-E01,-E02
Ring buffer in 8-bit
mode [BUF_DATA] s d6 d5 d4 d3 d2 d1 d0 x x x x x xxx
s = sign bit
x = not used bit
VTI ’9 TECHNOLOGIES |||]]
SCA3000 Series
VTI Technologies Oy 18/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
Table 8. Bit level description for acceleration registers of SCA3000-E04.
Byte MSB byte LSB byte
Bit number
Acceleration [mg] B7
Sign B6
4096 B5
2048 B4
1024 B3
512 B2
256 B1
128 B0
64 B7
32 B6
16 B5
8 B4
4 B3
2
B2:B0
xxx
SCA3000-E04
[X_LSB…Z_MSB] s d11 d10 d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 xxx
SCA3000-E04
Ring buffer in 11-bit
mode [BUF_DATA] s d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 x x xxx
SCA3000-E04
Ring buffer in 8-bit
mode [BUF_DATA] s d6 d5 d4 d3 d2 d1 d0 x x x x x xxx
s = sign bit
x = not used bit
Table 9. Bit level description for acceleration registers of SCA3000-E05.
Byte MSB byte LSB byte
Bit number
Acceleration [mg] B7
Sign B6
12800
B5
6400 B4
3200 B3
1600 B2
800 B1
400 B0
200 B7
100 B6
50 B5
25 B4
12.5 B3
6.25
B2:B0
xxx
SCA3000-E05
[X_LSB…Z_MSB] s d11 d10 d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 xxx
SCA3000-E05
Ring buffer in 11-bit
mode [BUF_DATA] s d9 d8 d7 d6 d5 d4 d3 d2 d1 d0 x x xxx
SCA3000-E05
Ring buffer in 8-bit
mode [BUF_DATA] s d6 d5 d4 d3 d2 d1 d0 x x x x x xxx
s = sign bit
x = not used bit
Address: 12h
Register name: TEMP_LSB, temperature LSB frame
Bits Mode Initial
Value Name Description
7:0 R 00h TEMP Temperature LSB frame
Address: 13h
Register name: TEMP_MSB, temperature MSB frame
Bits Mode Initial
Value Name Description
7:0 R 00h TEMP Temperature MSB frame
The bit level description for temperature data from TEMP_MSB and TEMP_LSB registers is
presented in Table 10. Temperature data is presented in unsigned format. The LSB bit (bit B5 or t0
in Table 10) weight is ~0.56°C. See section 2.6 for more detailed information of converting the data
to temperature in [°C].
Table 10. Bit level description for temperature registers [TEMP_MSB … TEMP_LSB].
Register TEMP_MSB TEMP_LSB
Bit number B7:B6 B5 B4 B3 B2 B1 B0 B7 B6 B5 B4:B0
Bit in temperature
register xx t8 t7 t6 t5 t4 t3 t2 t1 t0 xxxxx
x = not used bit
VTI ‘9 TECHNOLOGIES —
SCA3000 Series
VTI Technologies Oy 19/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
Address: 15h
Register name: BUF_COUNT, output ring buffer status
Bits Mode Initial
Value Name Description
7:0 R 00h COUNT
Count of available data samples in output ring buffer,
for more information see section 2.5.2.
Address: 16h
Register name: INT_STATUS, interrupt status register (all interrupts that are available in current
operation mode)
Bits Mode Initial
Value Name Description
7 R 0 BUF_FULL Output ring buffer is ¾ full
1 – Ring buffer is ¾ full
0 – Ring buffer is not full
6 R 0 BUF_HALF Output ring buffer is ½ full
1 – Ring buffer is ½ full
0 – Ring buffer is not full
5:4 Reserved
3 R 0 FFD Free-fall detection
1 – Free-fall detected (0 g acceleration)
0 – Free-fall not detected
2:0 R 000 MD Motion detector triggered channel indication
1xx – Trigger on Y-axis
x1x – Trigger on X-axis
xx1 – Trigger on Z-axis
3.4 Configuration Registers
SCA3000 configuration register (marked with 'Conf' in Table 5) contents and bit definitions are
described in this section. Configuration registers are used to configure SCA3000 operation and the
operation parameters.
Address: 00h
Register name: REVID, ASIC revision ID number tied in metal
Bits Mode Initial
Value Name Description
7:4 R 2h REVMAJ Major revision number
3:0 R 1h REVMIN Minor revision number
Address: 02h
Register name: STATUS, status register
Bits Mode Initial
Value Name Description
7:6 Reserved
5 R 0 LOCK Status of lock register
0 – Lock is closed
1 – Lock is open
4:2 Reserved
1 R 0 CSME EEPROM checksum error
1 – EEPROM checksum error
0 – No error
0 R 0 SPI_FRAME SPI frame error. Bit is reset, when next correct SPI
frame is received (only for products with SPI bus).
1 – SPI frame error
0 – No error
VTI ’9 TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 20/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
Address: 14h
Register name: MODE, operation mode selection
Bits Mode Initial
Value Name Description
7 RW 0 BUF_EN Output ring buffer
1 – Enabled
0 – Disabled (Buffer in power down)
6 RW 0 BUF_8BIT Output ring buffer data length
1 – Ring buffer is read in single 8 bit frame per
stored axis (8 bit mode)
0 – Ring buffer is read in two 8 bit frames per
stored axis (11 bit mode). Unused bits are
set to 0.
5 Reserved
4 RW 0 FFD_EN Free-fall detection
1 – Enabled
0 – Disabled (detection in power down)
3 Reserved
2:0 RW 000 MODE_BITS Selects SCA3000 series operation mode
000 – Normal measurement mode
010 – Optional measurement mode 1 (see Table 2)
001 – Optional measurement mode 2 (see Table 2)
011 – MD, Motion Detector
Other combinations are reserved
Address: 17h
Register name: I2C_RD_SEL, register address for I2C read operation
Bits Mode Initial
Value Name Description
7:0 W 00h ADDR Address of register to be read via I2C. Register is
used only for I2C read access.
Address: 18h
Register name: CTRL_SEL, Control register selector, UNLOCK REQUIRED
Bits Mode Initial
Value Name Description
7:5 RW 000 Reserved
4:0 RW 00000 SELECT Indirect control registers,
select register address for read / write access:
00001 – I2C_DISABLE
00010 – MD_CTRL (Motion Detector control)
00011 – MD_Y_TH (Motion Detector Y-
threshold)
00100 – MD_X_TH (Motion Detector X-
threshold)
00101 – MD_Z_TH (Motion Detector Z-
threshold)
01011 – OUT_CTRL (Output control)
Other combinations are reserved
CTRL_SEL register works as an address pointer for registers listed below. When this register is
written the content of selected register is available for reading/writing from/to register CTRL_DATA.
VTI ’9 TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 21/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
Address value: 00010
Register name: MD_CTRL, Motion Detector control (Indirect access via CTRL_SEL)
Bits Initial
Value Name Description Note
7:6 Reserved
5 0 REQ_Z 1 – Require trigger on Z-channel
0 – Not required
4 0 REQ_X 1 – Require trigger on X-channel
0 – Not required
3 0 REQ_Y 1 – Require trigger on Y-channel
0 – Not required
Bits 5:3 can be
used to build logical
AND operation
between channels.
Example:
X and Y = Require
X and Y, ignore Z
00 011 011
2 1 EN_Z 1 – Enable trigger on Z-channel
0 – Not required
1 1 EN_X 1 – Enable trigger on X-channel
0 – Not required
0 1 EN_Y 1 – Enable trigger on Y-channel
0 – Not required
Bits 2:0 can be
used to build logical
OR operation
between channels.
Example:
X or Y = Disable Z
00 000 011
Address value: 00011
Register name: MD_Y_TH, Motion Detector Y-threshold (Indirect access via CTRL_SEL)
Bits Initial
Value Name Description
7:0 10h or 08h Y_TH Threshold for Y-acceleration change when MD
is used.
Address value: 00100
Register name: MD_X_TH, Motion Detector X-threshold (Indirect access via CTRL_SEL)
Bits Initial
Value Name Description
7:0 10h or 08h X_TH Threshold for X-acceleration change when MD
is used.
Address value: 00101
Register name: MD_Z_TH, Motion Detector Z-threshold (Indirect access via CTRL_SEL)
Bits Initial
Value Name Description
7:0 10h or 08h Z_TH Threshold for Z-acceleration change when MD is
used.
Initial values for registers MD_X_TH, MD_Y_TH and MD_Z_TH vary with SCA3000 product types.
Initial value is:
10h for SCA3000-D01, SCA3000-D02, SCA3000-E01 and SCA3000-E02
08h for SCA3000-E04 and SCA3000-E05
The bit level descriptions for registers MD_X_TH, MD_Y_TH and MD_Z_TH are presented in,
Table 11 ...Table 14 below. The threshold levels are in unsigned format and they are absolute
values for the acceleration that triggers the motion detector interrupt. Values presented below are
typical threshold values and they are not factory calibrated.
VTI ’9 TECHNOLOGIES = = = =
SCA3000 Series
VTI Technologies Oy 22/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
Table 11. Bit level description for motion detector typical threshold levels (SCA3000-D01 and
SCA3000-D02).
Typical bit weights
Bit number B7 B6 B5 B4 B3 B2 B1 B0
SCA3000-D01, -D02
Acceleration [mg]
MD_X_TH, MD_TH_Z x x 1300 650 350 200 100 50
SCA3000-D01, -D02
Acceleration [mg]
MD_Y_TH x 1750 850 450 250 150 100 50
x = not used bit
Table 12. Bit level description for motion detector typical threshold levels (SCA3000-E01 and
SCA3000-E02).
Typical bit weights
Bit number B7 B6 B5 B4 B3 B2 B1 B0
SCA3000-E01, -E02
Acceleration [mg]
MD_X_TH, MD_TH_Z x x 2050 1050 550 300 150 100
SCA3000-E01, -E02
Acceleration [mg]
MD_Y_TH x 2700 1350 700 350 200 100 50
x = not used bit
Table 13. Bit level description for motion detector typical threshold levels (SCA3000-E04).
Typical bit weights
Bit number B7 B6 B5 B4 B3 B2 B1 B0
SCA3000-E04
Acceleration [mg]
MD_X_TH, MD_TH_Z x x 4100 2100 1100 600 300 200
SCA3000-E04
Acceleration [mg]
MD_Y_TH x 5400 2700 1400 700 400 200 100
x = not used bit
Table 14. Bit level description for motion detector typical threshold levels (SCA3000-E05).
Typical bit weights
Bit number B7 B6 B5 B4 B3 B2 B1 B0
SCA3000-E05
Acceleration [mg]
MD_X_TH, MD_TH_Z x x 11900 6100 3200 1700 900 600
SCA3000-E05
Acceleration [mg]
MD_Y_TH x 15600 7800 4100 2000 1200 600 300
x = not used bit
VTI ‘9 TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 23/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
Address value: 01011
Register name: OUT_CTRL, Output configuration (Indirect access via CTRL_SEL)
Bits Initial
Value Name Description
7:5 Reserved
4 1 BUF_X_EN Store X-axis acceleration data to ring buffer
1 – enabled
0 – disabled
3 1 BUF_Y_EN Store Y-axis acceleration data to ring buffer
1 – enabled
0 – disabled
2 1 BUF_Z_EN Store Z-axis acceleration data to ring buffer
1 – enabled
0 – disabled
1:0 00 BUF_RATE Additional data rate reduction after calibration
before data is loaded to ring buffer (no effect on
output registers data rate, see section 2.5.1)
11 – No rate reduction
10 – divide rate by 4
01 – divide rate by 2
00 – No rate reduction
Address: 1Eh
Register name: UNLOCK, Unlock register lock
Bits Mode Initial
Value Name Description
7:0 RW 00h KEY Lock can be opened by writing the following
sequence into this register:
00h, 50h, A0h Writing any other sequence closes the
lock. Lock state can be read from STATUS register.
Address: 21h
Register name: INT_MASK, HW interrupt mask register configures the operation of the INT pin.
Bits Mode Initial
Value Name Description
7 RW 0 BUF_F_EN Interrupt when output ring buffer is ¾ full
1 – Enabled
0 – Disabled
6 RW 1 BUF_H_EN Interrupt when output ring buffer is ½ full
1 – Enabled
0 – Disabled
5:2 Reserved
1 RW 0 INT_ALL Mask all interrupts (only effects on the INT-pin)
1 – Mask all interrupts (including free fall
detection and motion detector)
0 – Mask interrupts according to configured mode
0 RW 1 INT_ACT INT-pin signal activity
1 – INT active high (INT-pin high)
0 – INT active low (INT-pin low)
Address: 22h
Register name: CTRL_DATA, Control register data, UNLOCK REQUIRED
Bits Mode Initial
Value Name Description
7:0 RW 00h DATA Data bits [7:0] of selected 8-bit control register. Write
this register to actually perform the write operation to
selected location. See register CTRL_SEL for
information on register contents.
VTI ‘9 TECHNOLOGIES csn_\ I" scK ‘ 2 3 a 5 u 1 o w w u a v: m 15 w MDSI/MXMXMXAZXAIX‘DXRIM m1xon:xmsxonxouxmxonxma\ MISD \ PIE 007 006 006 004 DDS Do? Do! DOD 3mm“:
SCA3000 Series
VTI Technologies Oy 24/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
4 Serial Interfaces
Communication between the SCA3000 sensor and master controller is based on serial data
transfer and a dedicated interrupt line (INT-pin). Two different serial interfaces are available for the
SCA3000 sensor: SPI and I2C (Phillips specification V2.1). However, only one per product is
enabled by pre-programming in the factory. The SCA3000 acts as a slave on both the SPI and I2C
bus.
4.1 SPI Interface
SPI bus is a full duplex synchronous 4-wire serial interface. It consists of one master device and
one or more slave devices. The master is defined as a micro controller providing the SPI clock, and
the slave as any integrated circuit receiving the SPI clock from the master. The SCA3000 sensor
always operates as a slave device in master-slave operation mode. A typical SPI connection is
presented in Figure 5.
DATA OUT (MOSI)
DATA IN (MISO)
SERIAL CLOCK (SCK)
SS0
SS1
SS2
SS3
MASTER
MICROCONTROLLER
SI
SO
SCK
CS
SLAVE
SI
SO
SCK
CS
SI
SO
SCK
CS
SI
SO
SCK
CS
Figure 5. Typical SPI connection.
The data transfer uses the following 4-wire interface:
MOSI master out slave in µC SCA3000
MISO master in slave out SCA3000 µC
SCK serial clock µC SCA3000
CSB chip select (low active) µC SCA3000
4.1.1 SPI frame format
SCA3000 SPI frame format and transfer protocol is presented in Figure 6.
Figure 6. SPI frame format.
Each communication frame contains 16 bits. The first 8 bits in MOSI line contains info about the
operation (read/write) and the register address being accessed. The first 6 bits define the 6 bit
VTI ‘9 TECHNOLOGIES csa_| SCK Mug. nun I n1 n D=USh=X_MSB n n nIT]n n n D=U4h=X_LSB MIsD—.fll_lfl n n DI_I_I_I_I_I_I_I_I_I_II nI—In no tum—WW.— u. “”qu .u .. .m— g §§§§§3g§§ g §8§§§338§ 'j m m '3 m m a E 2 a E 3
SCA3000 Series
VTI Technologies Oy 25/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
address for the selected operation, which is defined by bit 7 (‘0’ = read ‘1’ = write), which is
followed by one zero bit. The later 8 bits in the MOSI line contain data for a write operation and are
‘don’t-care’ for a read operation. Bits from MOSI line are sampled in on the rising edge of SCK and
bits to MISO line are latched out on falling edge of SCK.
The first bits in the MISO line are the frame error bit (SPI_FRAME, bit 2) of the previous SPI frame
and odd parity bit (PAR, bit 8). Parity is calculated from data which is currently sent. Bit 7 is always
‘1’. The later 8 bits contain data for a read operation. During the write operation, these data bits are
previous data bits of the addressed register.
For write commands, data is written into the addressed register on the rising edge of CSB. If the
command frame is invalid as described in the section data will not be written into the register
(please see "error conditioning" in section 4.1.2).
For read commands, data is latched into the internal SPI output register (shift register) on the 8th
rising edge of SCK. The output register is shifted out MSB first over MISO output.
When the CSB is high state between data transfers, the MISO line is in the high-impedance state.
4.1.2 SPI bus error conditioning
While sending an SPI frame, if the CSB is raised to 1
- before sending 16 SCKs or
- the number of SCK pulses is not divisible by 8,
the frame error is activated and the frame is considered invalid. The status bit
STATUS.SPI_FRAME is set to indicate the frame error condition. During the next SPI, the frame
error bit is sent out as SPI_FRAME bit (see SPI_FRAME in MISO line in Figure 6).
STATUS.SPI_FRAME bit is reset, if correct frame is received.
When an invalid frame is received, the last command is simply ignored and the register contents
are left unchanged. If frame error happens while sending multiple samples in ring buffer mode, only
the last output value is considered invalid.
4.1.3 Examples of SPI communication
4.1.3.1 Example of register read
An example of 11 bit X-axis acceleration read command is presented in Figure 7. The master gives
the register address to be read via the MOSI line: '05' in hex format and '000101' in binary format,
register name is X_MSB (X-axis MSB frame). 7th bit is set to '0' to indicate the read operation.
The sensor replies to a requested operation by transferring the register content via MISO line. After
transferring the asked X_MSB register content, the master gives next register address to be read:
'04' in hex format and '000100' in binary format, register name is X_LSB (X-axis LSB frame). The
sensor replies to the requested operation by transferring the register content MSB first.
Figure 7. An example of SPI read communication.
VTI ‘9 TECHNOLOGIES csa‘l l— .z..................,..........,.“Hanan-m...... ... SCK : MDSI n n n I n I n n=USh=x_MSB Mlsufinlzlnflnflllllvlllll||!|||||||!||||l||!|||||||' 2 S x M53 )(_LSB Z_MSB Z_LSB E a ' ma w w m E- E 3: fl: 9: 3 u. :sa‘l l— .2“..,.......,.....,........=.,.n...z....1...»..........‘. SEK ; MUS, nnIIIIDn=DFh=EIUF_DATA MISC-\"Tnnonl‘llvllIIIIIIIIIIIIIIIIIIIIIIIIIIIIII— E Em BLIF_DATA m BLF_DATA m BLIF_DATA m BLIF_DATA m m In in §' g x1 22 v1 3% 21 3% x2 3 v: MODEBUF_BBIT I 1
SCA3000 Series
VTI Technologies Oy 26/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
4.1.3.2 Example of decremented register read
Figure 8 presents a decremented read operation where the content of four output registers is read
by one SPI frame. After normal register addressing and one register content reading, the µC keeps
the CSB line low and continues supplying the SCK pulses. After every 8 SCK pulses, the output
data address is decremented by one and the previous acceleration output register's content is
shifted out without parity bits. The parity bit in Figure 4 is calculated and transferred only for the first
data frame. From the X_LSB register address, the SCA3000 jumps to Z_MSB. Decremented
reading is possible only for registers X_LSB ... Z_MSB.
Figure 8. An example of decremented read operation.
4.1.3.3 Example of ring buffer read
An example of output ring buffer read by one SPI frame (ring buffer data length 8 bits) is presented
in Figure 9. The whole ring buffer read procedure is very similar to decremented read described
above. The output ring buffer is addressed (register name BUF_DATA). The SCA3000 sensor
continues shifting out the ring buffer content as long as µC continues supplying the SCK pulses.
Figure 9. An example of output ring buffer read operation.
VTI ® TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 27/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
4.2 I2C Interface
I2C is a 2-wire serial interface. It consists of one master device and one or more slave devices. The
master is defined as a micro controller providing the serial clock (SCL), and the slave as any
integrated circuit receiving the SCL clock from the master. The SCA3000 sensor always operates
as a slave device in master-slave operation mode. When using an SPI interface, a hardware
addressing is used (slaves have dedicated CSB signals), the I2C interface uses a software based
addressing (slave devices have dedicated bit patterns as addresses).
The SCA3000 is compatible to the Philips I2C specification V2.1. Main used features of the I2C
interface are:
- 10-bit addressing, SCA3000 I2C device address is 0x1F1
- Supports standard mode and fast mode
- Start / Restart / Stop
- Slave transceiver mode
- Designed for low power consumption
In addition to the Philips specification, the SCA3000 I2C interface supports multiple write and read
mode.
4.2.1 I2C frame format
4.2.1.1 I2C write mode
In I2C write mode, the first 8 bits after device address define the SCA3000 internal register address
to be written. If multiple data words are transferred by the master, the register address is
decreased automatically by one (see cases 1 and 2 in Figure 10).
4.2.1.2 I2C read mode
The read mode operates as described in Philips I2C specification. I2C read operation returns the
content of the register which address is defined in I2C_RD_SEL register. So when performing the
I2C read operation, the register address to be read has to be written into I2C_RD_SEL register
before actual read operation. Read operation starts from register address that has been written
earlier in I2C_RD_SEL register. Read data is acknowledged by I2C master. Automatic read
address change depends on the selected start address (see cases 3 and 4 in Figure 10).
- If address is some of registers between X_LSB Æ Z_MSB the register address is automatically
cycled as follows:
... ÆY_MSB Æ Y_LSB Æ X_MSB Æ X_LSB Æ Z_MSB Æ Z_LSB Æ Y_MSB Æ Y_LSB Æ ...
- If the start address is any other register, the read address is NOT automatically incremented or
decremented (the data transfer continues from the same address.) This enables the burst read
from output ring buffer (register BUF_DATA).
4.2.1.3 Decremented register read
Decremented reading is possible only for registers X_LSB ... Z_MSB. Refer to decremented read
with SPI interface section 4.1.3.2.
VTI 9/ TECHNOLOGIES i dew/me mm ‘5‘ WE s mum ° 5‘ regysm am mgxster my 3A Elms. Msanm SA a bus. MSB «m Hews: afldr 2m hyle AAAAAAAA ) CASE z ‘26 ‘5 bu wme {any numhev M by“: can be wrmen. \englh ‘5 determined by and candmnn generalefl by mzsl ‘ 4 regmemma ammo ‘ 4 regmemma mm M ‘ dew-:9 auav Islbyle a A dew-:9 addvznd byle SA mgxsteraddv m mu AAAAAAAA a bus. M33 «.3. a bus. Msa «m a bus. Msa «m cnsg a ‘26 x ml m mad “was: my SCAJDDO senes mglslev 5mm he wvmen «7 Emma mglslev dew-:9 mm m b e dew-:2 my 2nd byle new; addr ‘5: b :2 vegmey am. My w a M WW AH mm V b M E CASEA \zc ‘shll vead {any numhevquylescan hemmtlenglms detemuned by and unnambn amazed by maslev) Autumahc vegmer address changmg flenenfls an se‘ecled mu address m wzcjnfin (mated by adflrand aububn the «gum m mAA flex/me mm ‘5. hyle mm mm. mm mm am. mu 0 F 4 film“ 4 Malls mam. M Malls mam. E gm mam mm 5.3" mm m condmnn \zve Acknbwbugemm astev Acknnmedgemem ewes address. m hlls dew-:2 afldv 2m byle AAAAAAAA dew-:2 afldv m byte 23/43 v‘n Techno‘ogies 0y Rev.A.n7 www.v|\ li Doc,Nr. 5257SDDA.D7
SCA3000 Series
VTI Technologies Oy 28/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
4.2.2 Examples of I2C communication
Examples of I2C communication are presented below in Figure 10.
S 0 SA SA SA SA
device addr 1st byte
11110AA device addr 2nd byte
AAAAAAAA
register addr
8 bits, MSB first register data
8 bits, MSB first
CASE 1: I2C 8 bit write
S 0 SA SA SA SA
device addr 1st byte
11110AA device addr 2nd byte
AAAAAAAA register addr
8 bits, MSB first
register data, addr + 0
8 bits, MSB first
CASE 2: I2C 16 bit write (any number of bytes can be written, length is determined by end condition generated by master)
SA
register data, addr - 1
8 bits
,
MSB first
E
S 0 SA SA MA
device addr 1st byte
11110AA device addr 2nd byte
AAAAAAAA register data, addr
8 bits, MSB first
CASE 3: I2C 8 bit read, read address for SCA3000 series register should be written to I2C_RD_SEL register
CASE 4: I2C 16 bit read (any number of bytes can be read, length is determined by end condition generated by master).
Automatic register address changing depends on selected start address in I2C_RD_SEL (noted by addr and addr_x on the figure).
E
S = Start condition
RS = Repeated start condition
E = End condition
SA = Slave Acknowledgement
MA = Master Acknowledgement
AA = Device address, 10 bits
Read/write select bit
(0=write, 1=read)
RS device addr 1st byte
11110AA 1SA
S 0 SA SA MA
device addr 1st byte
11110AA device addr 2nd byte
AAAAAAAA register data, addr
8 bits, MSB first E
RS device addr 1st byte
11110AA 1SA MA
register data, addr_x
8 bits, MSB first
E
Figure 10. I2C frame format.
VTI ’9 TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 29/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
5 Electrical Characteristics
All voltages are reference to ground. Currents flowing into the circuit have positive values.
5.1 Absolute maximum ratings
The absolute maximum ratings of the SCA3000 are presented in Table 15 below.
Table 15. Absolute maximum ratings of the SCA3000
Parameter Value Unit
Supply voltage (Vdd) -0.3 to +3.6 V
Voltage at input / output pins -0.3 to (Vdd + 0.3) V
ESD (Human body model) ±2 kV
Storage temperature -40 ... +125 °C
Storage / operating temperature -40 ... +85 °C
Mechanical shock * > 10 000 g
Ultrasonic cleaning Not allowed
* 1 m drop on concrete may cause >>10000 g shock.
ULTRASONIC AGITATION NOT ALLOWED.
5.2 Power Supply
Please refer to the corresponding product datasheet.
5.3 Digital I/O Specification
5.3.1 Digital I/O DC characteristics
Table 16. DC characteristics of digital I/O pins.
No. Parameter Conditions Symbol Min Typ Max Unit
Input: CSB, MOSI, Xreset,
SCK_SCL has no pull up / pull down
1 Pull up current:
CSB VIN = 0 V IPU 10 50
µA
2 Pull down current:
MOSI VIN = Dvio IPD 10 50 µA
3 Pull up current
Xreset VIN = 0 V IPU 3 10
µA
4 Input high voltage VIH 0.7*Dvio V
5 Input low voltage VIL 0.3*Dvio V
6 Hysteresis VHYST 0.1*Dvio V
Output terminal: MISO_SDA, INT
7 Output high voltage I > -4 mA VOH 0.8*Dvio Dvio V
8 Output low voltage I < 4 mA VOL 0 0.2*Dvio V
9 Tristate leakage 0 < VMISO < 2.7 V ILEAK -2 2
µA
5.3.2 Digital I/O level shifter
All the SCA3000 products have an internal level shifter that can be used to interface e.g. a micro
controller using lower supply than the SCA3000. The level shifter is "programmed" by providing the
supply voltage of the interfaced device to the DVIO-pin. Please refer to the corresponding product
data sheet for details.
VTI ‘9 TECHNOLOGIES 1/T
SCA3000 Series
VTI Technologies Oy 30/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
5.3.3 SPI AC characteristics
The AC characteristics of the SCA3000 SPI interface are defined in Figure 11 and in Table 17.
CSB
SCK
MOSI
MISO
TLS1 TCH
THOL TSET
TVAL1 TVAL2 TLZ
TLS2 TLH
MSB in
MSB out
LSB in
LSB out
DATA out
DATA in
TCL
Figure 11. Timing diagram for SPI communication.
Table 17. AC characteristics of SPI communication.
Parameter Conditions Symbol Min Typ Max Unit
Terminal CSB, SCK
1 Time from CSB (10%)
to SCK (90%)1 T
LS1 T
per/2 ns
2 Time from SCK (10%)
to CSB (90%)1 TLS2 Tper/2 ns
Terminal SCK
3 SCK low time Load
capacitance at
MISO < 35 pF
TCL 0.80*
Tper/2 Tper/2 ns
4 SCK high time Load
capacitance at
MISO < 35 pF
TCH 0.80*
Tper/2 Tper/2 ns
5 SCK Frequency fsck =
1/Tper Product
specific MHz
Terminal MOSI, SCK
6 Time from changing
MOSI (10%, 90%) to
SCK (90%)1. Data
setup time
TSET Tper/4 ns
7 Time from SCK (90%)
to changing MOSI
(10%, 90%)1. Data
hold time
T
HOL T
per/4 ns
Terminal MISO, CSB
8 Time from CSB (10%)
to stable MISO (10%,
90%)
Load
capacitance at
MISO < 35 pF
TVAL1 Tper/4 ns
9 Time from CSB (90%)
to high impedance
state of MISO1.
Load
capacitance at
MISO < 35 pF
TLZ T
per/4 ns
Terminal MISO, SCK
10 Time from SCK (10%)
to stable MISO (10%,
90%)1.
Load
capacitance at
MISO < 35 pF
TVAL2 1.3· Tper/4 ns
010 . 4 0 8. «3 8,5 3: Ed , T 3.: 8d = 6.40 TECHNOLOGIES VTI ‘9 0.43 (18x)
SCA3000 Series
VTI Technologies Oy 31/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
Terminal MOSI, CSB
11 Time between SPI
cycles, CSB at high
level (90%)
T
LH 4 · Tper ns
Tper is SCK period
5.3.4 I2C AC characteristics
Please, see Phillips Semiconductors, The I2C bus specification, Version 2.1, January 2000, pp. 31-
33.
6 Package Characteristics
6.1 Dimensions
The package dimensions are presented in Figure 12 below (dimensions in millimeters [mm] with
±50 µm tolerance).
Figure 12. SCA3000 package dimensions.
VTI (9 TECHNOLOGIES Topview, pin 01 "may on lop sums:
SCA3000 Series
VTI Technologies Oy 32/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
7 Application information
7.1 Pin Description
SCA3000 pin numbers are presented in Figure 14 below and pin descriptions in Table 18.
Figure 13. SCA3000 sensing directions. Figure 14. SCA3000 pin numbers.
Table 18. SCA3000 pin descriptions.
Pin # Name SCA3000-D01, SCA3000-E01,
SCA3000-E04
SCA3000-D02, SCA3000-E02
1 NC Not connected Not connected
2 XRESET External reset, active low External reset, active low
3 INT Interrupt output Interrupt output
4 CLK Connect to ground Connect to ground
5 DVSS Digital ground Digital ground
6 DVDD Digital supply Digital supply
7 DVIO Digital I/O supply Digital I/O supply
8 CSB Chip select Not connected
9 NC Not connected Not connected
10 NC Not connected Not connected
11 SCK_SCL SPI serial clock (SCK) I2C serial clock (SCL)
12 MISO_SDA SPI data out (MISO) I2C data in / out (SDA)
13 MOSI SPI data in (MOSI) Not connected
14 AVDD Analog supply Analog supply
15 AVSS Analog ground Analog ground
16 AVSS Analog ground Analog ground
17 ATSTIO Not connected Not connected
18 NC Not connected Not connected
7.2 Recommended circuit diagram
1. Connect 100 nF SMD capacitor between each supply voltage and ground level.
2. Connect 1 µF capacitor between each supply voltage and ground level.
3. Use one regulator for analog and digital supply (AVDD and DVDD).
4. Use separate regulator for digital IO supply (DVIO).
5. Xreset is needed always in start up: when Xreset is low, raise power supplies inside
specification, then set Xreset high.
6. INT-pin is used with output buffer as well as in Free Fall and Motion Detection mode.
7. Serial interface (SPI or I2C) logical '1' level is determined by DVIO supply voltage level.
Recommended circuit diagram for the SCA3000 with SPI interface is presented in Figure 15 below.
VTI ‘9 TECHNOLOGIES AVEIELAAJDVDD‘ SCAMOLSP‘ NC Nfigl; msgr msnmsnu 16 MY wr Avss ‘5 cm Avss “ was won 0 mm) Mcsw W \ MCS‘ we we M‘SO,SDA 1; we (SE csa 5 ,m m / scw NC mi r7 W‘ r7 mfi N7 , : : [N‘ND ACND A»run,a¢,uvbu :* SCAEQOOJZC ; m m 3 my 3 msmrsna 16 m ; . W ms 15 5 cw ms M 8 W W U 7 mp WT m ‘ a WWW» 11 gm Toss WM 10 . m 7m m7 mnn
SCA3000 Series
VTI Technologies Oy 33/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
Recommended circuit diagram for the SCA3000 with I2C interface is presented in Figure 16 below.
Figure 15. Recommended circuit diagram for the SCA3000 with SPI interface.
Figure 16. Recommended circuit diagram for the SCA3000 with I2C interface.
7.3 Recommended PWB layout
General PWB layout recommendations for SCA3000 products (refer to Figure 15, Figure 16 and
Figure 17):
1. Locate 100 nF SMD capacitors right next to the SCA3000 package.
2. 1 µF capacitors can be located near the node where AVDD and DVDD are routed on separate
ways.
3. Use separate ground planes for AGND and DGND. Connect separate ground planes together
on PWB.
4. Use double sided PWB, connect the bottom side plane to DGND.
VTI ‘9 TECHNOLOGIES 7.25 Pitch _ _ oao - - - - - - - - 6.95 - - - - 0.551- - — 0551— >—<>—< o="" .9="" ‘1="" m="" n="" n="" u!="">
SCA3000 Series
VTI Technologies Oy 34/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
Recommended PWB pad layout for SCA3000 is presented in Figure 17 below (dimensions in
millimeters, [mm]).
Recommended PWB layout for the SCA3000 with SPI interface is presented in Figure 18 below
(circuit diagram presented in Figure 15 above).
Figure 17. Recommended PWB pad layout for SCA3000.
Figure 18. Recommended PWB layout for SCA3000 with SPI interface (not actual size, for
reference only).
VTI (9 TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 35/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
Recommended PWB layout for SCA3000 with I2C interface is presented in Figure 19 below (circuit
diagram presented in Figure 16 above).
Figure 19. Recommended PWB layout for SCA3000 with I2C interface (not actual size,
for reference only).
7.4 Assembly instructions
The Moisture Sensitivity Level (MSL) of the SCA3000 component is 3 according to the IPC/JEDEC
J-STD-020C. Please refer to the document "TN54 SCA3000 Assembly Instructions" for more
detailed information of SCA3000 assembly.
7.5 Tape and reel specifications
Please refer to the document "TN54 SCA3000 Assembly Instructions" for tape and reel
specifications.
VTI ‘6 TECHNOLOGIES @111
SCA3000 Series
VTI Technologies Oy 36/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
8 Data sheet references
8.1 Offset
SCA3000's offset will be calibrated in X = 0 g, Y = 0 g, and Z = +1 g (Z measuring axis is parallel to
earth’s gravitation) position, see Figure 20.
Z-axis in +1 g
position
Y
Earth’s
gravitation
X
Pin #1
Figure 20. SCA3000 offset (0 g) position.
8.1.1 Offset calibration error
Offset calibration error is the difference between the sensor's actual output reading and the nominal
output reading in calibration conditions. Error is calculated by
Equation 2
1000
=
Sens
OutputOutput
Offset axisX
raxisCalibEX ,
where OutputX-axisCalibEr is sensor’s X-axis calibration error in [mg], OutputX-axis is sensor’s X-axis
output reading [counts], Output is sensor’s nominal output in 0 g position and Sens sensor’s nominal
sensitivity [counts/g].
8.1.2 Offset temperature error
Offset temperature error is the difference between the sensor's output reading in different
temperatures and the sensor’s calibrated offset value at room temperature. Error is calculated by
Equation 3
1000
@@
@
=
Sens
OutputOutput
Offset RTaxisXTaxisX
TaxisTempErX ,
where OutputX-axisTempEr@T is sensor’s X-axis temperature error in [mg] in temperature T, OutputX-axis@T
is sensor’s X-axis output reading [counts] in temperature T, OutputX-axis@T X-axis output reading
[counts] at room temperature RT and Sens sensor’s nominal sensitivity [counts/g]. Sensor is in 0 g
position for every measurement point.
EEEEEEEEEEEE
SCA3000 Series
VTI Technologies Oy 37/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
8.2 Sensitivity
During sensitivity calibration, the sensor is placed in ±1 g positions having one of the sensor’s
measuring axis at a time parallel to the earth’s gravitation, see Figure 21.
Sensitivity is calculated by
Equation 4
g
OutputOutput
Sens gaxisYgaxisY
axisY 2
1@1@ +
=,
where SensY-axis is sensor’s Y-axis sensitivity in [counts/g], OutputY-axis@+1g sensor’s Y-axis output
reading [counts] in +1 g position and OutputY-axis@-1g is sensor’s Y-axis output reading [counts] in -1 g
position.
Pin #1
X
Y-axis in +1 g
position
Z
X Z
Y-axis in -1 g
position
Earth’s
gravitation
Pin #1
Figure 21. SCA3000 positions for Y-axis sensitivity measurement.
8.2.1 Sensitivity calibration error
Sensitivity calibration error is the difference between sensor’s measured sensitivity and the nominal
sensitivity at room temperature conditions. Error is calculated by
Equation 5
%100
=
Sens
SensSens
Sens axisY
raxisCalibEY ,
where SensY-axisCalibEr is sensor’s Y-axis sensitivity calibration error in [%], SensY-axis sensor’s Y-axis
sensitivity [counts/g] at room temperature conditions and Sens is sensor’s nominal sensitivity
[counts/g].
8.2.2 Sensitivity temperature error
Sensitivity temperature error is the difference between sensor’s sensitivity at different temperatures
and the calibrated sensitivity. Error is calculated by
Equation 6
%100
@
@@
@
=
RTaxisY
RTaxisYTaxisY
TaxisTempErY Sens
SensSens
Sens ,
where SensY-axisTempEr@T is sensor’s Y-axis sensitivity temperature error in [%] in temperature T, SensY-
axis@T is sensor’s measured Y-axis sensitivity [counts/g] at temperature T and SensY-axis@RT is sensor’s
measured Y-axis sensitivity [counts/g] at room temperature RT.
VTI ‘9 TECHNOLOGIES SCAaoou output at positive sensmvily ca‘ibralicn point \A N
SCA3000 Series
VTI Technologies Oy 38/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
8.3 Linearity
The linearity error characterization method described below is applied for those SCA3000 series
components that have measuring range ±3g or below.
Accurate input acceleration needed in linearity characterization is generated using centrifugal force
in centrifuge, see Figure 22. The RPM of the centrifuge is sweeped so that wanted input
acceleration values are applied in parallel to the sensor’s measuring axis.
Linearity error is the deviation from the straight line through sensor’s sensitivity calibration points,
see Figure 23.
Linearity error is calculated by
Equation 7
%100
@@
@
=
FSSens
OutputOutput
LinEr accaccaxisZ
accaxisZ ,
where LinErZ-axis@acc is sensor’s Z-axis linearity error [%FS] on input acceleration acc, OutputZ-axis@acc
is sensor’s measured Z-axis output [counts] on input acceleration acc, Output@acc is sensor’s
X
Y
Z
Centrifugal
acceleration
for Z-axis
Pin #1
Figure 22. Centrifugal acceleration applied for SCA3000 Z-axis.
Input acceleration [g] (centrifugal
acceleration in parallel to
SCA3000 measuring axis)
SCA3000 output at
positive sensitivity
calibration point
SCA3000 linearity
error in [g] at input
acceleration acc
+1
g
-1 g
Possible offset error is not
included into linearity error
SCA3000 output
readings
Sensor’s ideal
output
Acceleration reading
from SCA3000 [g]
acc
Figure 23. SCA3000’s linearity error at input acceleration acc.
VTI ‘9 TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 39/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
nominal output [counts] on input acceleration acc, Sens is sensor’s nominal sensitivity [counts/g] and
FS is sensor’s full scale measuring range [g] (for example for SCA3000-D01 ±2g FS = 2 g).
Sensor’s ideal output Output@acc (in Equation 7) is calculated from the straight line through
sensitivity calibration points (the red straight line in Figure 23). Nominal output is calculated by
Equation 8
222
111111
@
gggggg
acc
OutputOutput
g
OutputOutput
accoffset
g
OutputOutput
accOutput +++
+
+
=+
= ,
where Output@acc is sensor’s nominal output [counts] with input acceleration acc in [g], Output+1g is
sensor’s measured output [counts] at +1 g input acceleration and Output-1g is sensor’s measured
output at -1 g input acceleration. Possible offset term [counts] is included into nominal output,
because it is not included in to linearity error.
8.4 Noise
Output noise nX, nY and nZ in X,Y and Z directions is the measured standard deviation of the output
values when the sensor is in 0 g position at room temperature. Average noise/axis is calculated by
Equation 9
()
222
3
1
ZYX nnnn ++= ,
where n is sensor’s noise [g] per axis, nX is sensor’s X-axis noise [g], nY is sensor’s Y-axis noise [g]
and nZ is sensor’s Z-axis noise [g].
SCA3000 demo-kit design can be used as a reference design for noise measurements, refer to
“SCA3000 DEMO KIT User Manual 8259300”.
8.5 Bandwidth
Signal bandwidth is measured in a shaker by sweeping the piston movement frequency with
constant amplitude (Figure 24).
Z
Earth’s
gravitation
Shaker
movement
in parallel
to Z-axis
Y
X
Pin #1
Figure 24. SCA3000 movement in Z-axis bandwidth measurement.
8.6 Cross-axis sensitivity
Cross-axis sensitivity is sum of the alignment and the inherent sensitivity errors. Cross-axis
sensitivity of one axis is a geometric sum of the sensitivities in two perpendicular directions.
Cross-axis sensitivity [%] of X-axis is given by
VTI 3 TECHNOLOGIES 7 fl
SCA3000 Series
VTI Technologies Oy 40/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
Equation 10
%,100
22
+
±=
X
XZXY
XS
SS
Cross
where SXY is X-axis sensitivity to Y-axis acceleration [Count/g], SXZ is X-axis sensitivity to Z-axis
acceleration [Count/g] and SX is sensitivity of X-axis [Count/g].
Cross-axis sensitivity [%] of Y-axis is given by
Equation 11
%,100
22
+
±=
Y
YZYX
YS
SS
Cross
where SYX is Y-axis sensitivity to X-axis acceleration [Count/g], SYZ is Y-axis sensitivity to Z-axis
acceleration [Count/g] and SY is sensitivity of Y-axis [Count/g].
Cross-axis sensitivity [%] of Z-axis is given by
Equation 12
%,100
22
+
±=
Z
ZYZX
ZS
SS
Cross
where SZX is Z-axis sensitivity to X-axis acceleration [Count/g], SZY is Z-axis sensitivity to Y-axis
acceleration [Count/g] and SZ is sensitivity of Z-axis [Count/g].
Cross-axis sensitivity of SCA3000 family is measured in centrifuge over specified measurement
range during qualification. Correct mounting position of component is important during the
measurement of cross-axis sensitivity.
8.7 Turn-on time
Turn-on time is the time when the last of one X, Y, Z axis output readings stabilizes into its final
value after XRESET is pulled high. The final value limits in turn-on time measurements is defined to
be ±1 % of the sensor’s full scale measuring range (for example for SCA3000-D01 ±2g
FS = 2 g). Turn-on time definition for Z-axis is presented in Figure 25 below.
SCA3000 output
inside ±1% FS
limits
SCA3000
Z-axis output
Acceleration
Turn on time Time scale
XRESET rise up
SCA3000 starts
Figure 25. Turn-on time definition for one axis.
VTI ’9 TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 41/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
9 Order Information
Order code Description Packing Quantity
SCA3000-D01-1 3-Axis accelerometer with SPI interface, +/-2g, 100 pcs T&R 100
SCA3000-D01-10 3-Axis accelerometer with SPI interface, +/-2g, 1000 pcs T&R 1000
SCA3000-D01-25 3-Axis accelerometer with SPI interface, +/-2g, 2500 pcs T&R 2500
SCA3000-D02-1 3-Axis accelerometer with I2C interface, +/-2g, 100 pcs T&R 100
SCA3000-D02-10 3-Axis accelerometer with I2C interface, +/-2g, 1000 pcs T&R 1000
SCA3000-D02-25 3-Axis accelerometer with I2C interface, +/-2g, 2500 pcs T&R 2500
SCA3000-E01-1 3-Axis accelerometer with SPI interface, +/-3g, 100 pcs T&R 100
SCA3000-E01-10 3-Axis accelerometer with SPI interface, +/-3g, 1000 pcs T&R 1000
SCA3000-E01-25 3-Axis accelerometer with SPI interface, +/-3g, 2500 pcs T&R 2500
SCA3000-E02-1 3-Axis accelerometer with I2C interface, +/-3g, 100 pcs T&R 100
SCA3000-E02-10 3-Axis accelerometer with I2C interface, +/-3g, 1000 pcs T&R 1000
SCA3000-E02-25 3-Axis accelerometer with I2C interface, +/-3g, 2500 pcs T&R 2500
SCA3000-E04-1 3-Axis accelerometer with SPI interface, +/-6g, 100 pcs T&R 100
SCA3000-E04-10 3-Axis accelerometer with SPI interface, +/-6g, 1000 pcs T&R 1000
SCA3000-E04-25 3-Axis accelerometer with SPI interface, +/-6g, 2500 pcs T&R 2500
SCA3000-E05-1 3-Axis accelerometer with SPI interface, +/-18g, 100 pcs T&R 100
SCA3000-E05-10 3-Axis accelerometer with SPI interface, +/-18g, 1000 pcs T&R 1000
SCA3000-E05-25 3-Axis accelerometer with SPI interface, +/-18g, 2500 pcs T&R 2500
SCA3000-D01 PWB PWB assy, 3-Axis accelerometer with SPI interface, +/-2g Bulk 1
SCA3000-D02 PWB PWB assy, 3-Axis accelerometer with I2C interface, +/-2g Bulk 1
SCA3000-E01 PWB PWB assy, 3-Axis accelerometer with SPI interface, +/-3g Bulk 1
SCA3000-E02 PWB PWB assy, 3-Axis accelerometer with I2C interface, +/-3g Bulk 1
SCA3000-E04 PWB PWB assy, 3-Axis accelerometer with SPI interface, +/-6g Bulk 1
SCA3000-E05 PWB PWB assy, 3-Axis accelerometer with SPI interface, +/-18g Bulk 1
SCA3000-D01DEMO SCA3000-D01 DEMOKIT Bulk 1
VTI ‘9 TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 42/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
10 Document Change Control
Version Date Change Description
0.01 09.09.2005 Initial draft.
.... ...
0.08 20.09.2005 Draft release for schematic and layout design.
0.09 23.09.2005 FF and MD description added.
0.10 12.10.2005
Introduction and functional descriptions edited,
measurement mode, ring buffer, temperature measurement, interrupt, oscillator, reset and register
descriptions added. Register and bit names changed to be more descriptive.
0.11 13.10.2005 Typo etc minor corrections.
0.12 14.10.2005 Draft release.
0.13 01.11.2005 Register initial values and examples added.
0.14 09.11.2005 Language corrections.
0.15 26.01.2006 New product versions updated.
Output and ring buffer bit level definitions changed. This definition is valid from samples v0.3
onwards. Register level changes in temperature output.
0.16 15.02.2006
Updated:
- absolute maximum ratings,
- temperature output equation,
- I2C device address,
specification references
0.17 14.03.2006 Updated:
- recommended circuit diagrams, sections “Packing” and “Handling and storage” added
0.18 27.03.2006 Layout change
A 27.04.2006 Updated:
- recommended circuit diagrams,
- sections “Packing” and “Handling and storage”
- section “Specification references” updated and renamed to “Data sheet references”
MD threshold levels
A.01 27.06.2006
Updated:
- document name changed to "SCA3000 Product Family Specification"
- section "6.1 Package dimensions" updated
sections "7.4 Solder paste and stencil parameters" and "7.5 Reflow" updated to "7.4 Assembly
instructions"
- section "9.1 Packing and handling" updated to "7.5 Tape and reel specifications"
Contact information
A.02 30.6.2006 Order information added
A.03 11.9.2006 SCA3000-E04 information added
A.04 27.03.2007 Added:
- SCA3000-E04 wide band measurement mode,
- Typos corrected
- New product types: SCA3000-E05 and SCA3000-L01
A.05 01.06.2007
Added:
- New product type: SCA3000-D03
- I2C communication added for SCA3000-L01
A.06 30.10.2007 Corrections: typos, axis orientation
A.07 02.02.2009
Corrected recommended PWB layouts. Removed references to D03 and L01.
VTI ® TECHNOLOGIES
SCA3000 Series
VTI Technologies Oy 43/ 43
www.vti.fi Doc.Nr. 8257300A.07 Rev.A.07
11 Contact Information
Finland
(head office)
VTI Technologies Oy
P.O. Box 27
Myllynkivenkuja 6
FI-01621 Vantaa
Finland
Tel. +358 9 879 181
Fax +358 9 8791 8791
E-mail: sales@vti.fi
Germany
VTI Technologies Oy
Branch Office Frankfurt
Rennbahnstrasse 72-74
D-60528 Frankfurt am Main,
Germany
Tel. +49 69 6786 880
Fax +49 69 6786 8829
E-mail: sales.de@vti.fi
USA
VTI Technologies, Inc.
One Park Lane Blvd.
Suite 804 - East Tower
Dearborn, MI 48126
USA
Tel. +1 313 425 0850
Fax +1 313 425 0860
E-mail: sales@vtitechnologies.com
Japan
VTI Technologies Oy
Tokyo Office
Tokyo-to, Minato-ku 2-7-16
Bureau Toranomon 401
105-0001
Japan
Tel. +81 3 6277 6618
Fax +81 3 6277 6619
E-mail: sales.japan@vti.fi
China
VTI Technologies Shanghai Office
6th floor, Room 618
780 Cailun Lu
Pudong New Area
201203 Shanghai
P.R. China
Tel. +86 21 5132 0417
Fax +86 21 513 20 416
E-mail: sales.china@vti.fi
To find out your local sales
representative visit www.vti.fi

Products related to this Datasheet

ACCELEROMETER 2G SPI 18SMD
BOARD PWB W/SCA3000-D01
ACCELEROMETER 2G I2C 18SMD
BOARD PWB W/SCA3000-D02
ACCELEROMETER 3G SPI 18SMD
BOARD PWB W/SCA3000-E01
ACCELEROMETER 3G I2C 18SMD
BOARD PWB W/SCA3000-E02
SCA3000-D01 DEMOKIT
ACCELEROMETER 2G SPI 18SMD
ACCELEROMETER 2G I2C 18SMD
ACCELEROMETER 3G SPI 18SMD
ACCELEROMETER 3G I2C 18SMD
ACCELEROMETER 6G SPI 18SMD
BOARD PWB W/SCA3000-E04
ACCELEROMETER 6G SPI 18SMD
ACCELEROMETER 18G SPI 18SMD
ACCELEROMETER 18G SPI 18SMD
BOARD PWB W/SCA3000-E05
ACCELEROMETER 18G SPI 18SMD