Aceinna IMU383 Series User manual

IMU383 Series User’s Manual
Document Number: 7430-1398-01
1
IMU383 SERIES USER MANUAL
Document Part Number: 7430-1398-01

IMU383 Series User’s Manual
Document Number: 7430-1398-01
2
ACEINNA, Inc.
email: [email protected], website: www.aceinna.com

IMU383 Series User’s Manual
Document Number: 7430-1398-01
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Revision history
Date
Document
Revision
Associated FW
Version
Description
Author(s)
Aug 22, 2019
Rev. A
v1.1.x
Draft release of IMU383 manual
Joseph Motyka
Dec 9, 2019
Rev. B
v1.1.x
Updates to manual to describe fault
detection and settings
Joseph Motyka
Dec 18, 2019
Rev. C
v1.1.x
Fixed links to and formatting of
tables and figures.
Joseph Motyka
April 7, 2020
Rev. D
v1.1.6 / v25
Updates to manual for FW version
1.1.6, fix errors and formatting
Andrey Bondarev
Rishit Borad

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Table of Contents
1. Introduction ..............................................................................................................................9
1.1. Manual overview...............................................................................................................9
1.2. Overview of the IMU383 Series Inertial Measurement Unit ............................................9
2. Interface..................................................................................................................................11
2.1. Electrical interface...........................................................................................................11
2.1.1. Connector...................................................................................................................11
2.1.2. Power and ground pins...............................................................................................12
2.1.3. Serial interface............................................................................................................12
2.1.3.1. SPI com synchronization input..........................................................................12
2.1.4. Reserved –factory use only .......................................................................................13
2.2. Mechanical interface .......................................................................................................13
3. Theory of operation................................................................................................................14
3.1. Default coordinate system...............................................................................................15
3.1.1. Advanced settings ......................................................................................................16
3.2. Data processing chain......................................................................................................16
3.2.1. Sensor fault detection.................................................................................................16
3.2.1.1. Configuration field settings for sensor enable and sensor output select............17
3.2.1.2. User Settings......................................................................................................17
3.2.2. Advanced settings ......................................................................................................17
Note on filter settings..........................................................................................................18
3.2.3. Built-In test.................................................................................................................18
4. SPI port interface definition....................................................................................................20
4.1. SPI register map ..............................................................................................................20
4.2. SPI register read methodology ........................................................................................22
4.2.1. SPI Polled mode read.................................................................................................22
4.2.2. SPI Burst-mode read ..................................................................................................23
4.2.3. Output data scaling.....................................................................................................26
4.2.4. System information registers......................................................................................26
4.2.5. Diagnostic status register............................................................................................27
4.2.6. Sensors status registers...............................................................................................28
4.2.7. Hardware and software version..................................................................................28
4.3. SPI register write methodology.......................................................................................29
4.4. Unit configuration registers.............................................................................................30
4.4.1. Data-Ready and Self-test registers.............................................................................30

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4.4.2. Output data rate..........................................................................................................31
4.4.3. Rate-Sensor scaling and Low-Pass filter....................................................................31
4.4.4. Axis orientation settings.............................................................................................33
4.4.5. Saving the configuration to EEPROM.......................................................................34
4.4.6. Sensor control registers..............................................................................................34
4.4.7. Fault detection control registers.................................................................................35
4.5. Suggested operation conditions.......................................................................................36
4.5.1. Startup timing.............................................................................................................36
4.5.2. SPI timing...................................................................................................................36
4.6. Signal synchronization....................................................................................................37
Method 1- Using the sensor sampling indicator (Pin 1).....................................................38
Method 2- Using the Timestamp registers in the Extended Burst Message........................38
4.7. Bootloader.......................................................................................................................38
5. UART interface definition......................................................................................................39
5.1. General settings...............................................................................................................39
5.2. Number formats...............................................................................................................39
5.3. Packet format...................................................................................................................40
5.3.1. Packet header..............................................................................................................40
5.3.2. Packet type .................................................................................................................40
5.3.3. Payload length............................................................................................................41
5.3.4. Payload.......................................................................................................................41
5.3.5. 16-bit CRC-CCITT ....................................................................................................41
5.3.6. Messaging overview...................................................................................................41
6. Standard UART commands and messages.............................................................................44
6.1. Link test...........................................................................................................................44
6.1.1. Ping command............................................................................................................44
6.1.3. Echo command...........................................................................................................44
6.1.4. Echo response.............................................................................................................44
6.2. Interactive commands......................................................................................................45
6.2.1. Get Packet request......................................................................................................45
6.2.2. Error response ............................................................................................................45
6.3. Output packets (Polled)...................................................................................................45
6.3.1. Identification data packet ...........................................................................................46
6.3.2. Version data packet....................................................................................................46
6.3.3. Test 0 (Detailed BIT and status) packet.....................................................................47

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6.4. Output packets (polled or continuous) ............................................................................47
6.4.1. Scaled sensor data packet 0........................................................................................48
6.4.2. Scaled sensor data packet 1 (default IMU data packet)..............................................49
7. Advanced UART commands..................................................................................................51
7.1. Configuration fields.........................................................................................................51
7.1.1. Packet rate divider......................................................................................................52
7.1.2. Unit baudrate..............................................................................................................52
7.1.3. Continuous packet type field......................................................................................52
7.1.4. Digital filter settings...................................................................................................52
7.1.5. Orientation field .........................................................................................................53
7.1.6. Sensor enable setting and Output select setting .........................................................54
7.1.7. Fault-Detection status fields.......................................................................................56
7.1.8. Fault-Detection Enable/Disable .................................................................................56
7.2. Read/Write of configuration fields..................................................................................56
7.2.1. Write Fields command ...............................................................................................56
7.2.2. Write Fields response.................................................................................................57
7.2.3. Set Fields command...................................................................................................58
7.2.4. Set Fields response.....................................................................................................58
7.2.5. Read Fields command................................................................................................59
7.2.6. Read Fields response..................................................................................................59
7.2.7. Get Fields command...................................................................................................60
7.2.8. Get Fields response ....................................................................................................60
8. Advanced UART Port BIT.....................................................................................................62
8.1. Built In Test (BIT) and Status fields ...............................................................................62
8.2. Master BIT and Status (BITstatus) field .........................................................................62
8.3. hardwareBIT field ...........................................................................................................63
8.4. softwareDataBIT field.....................................................................................................63
8.5. hardwareStatus field........................................................................................................64
8.6. sensorStatus field.............................................................................................................64
9. Bootloader ..............................................................................................................................65
9.1. Updating firmware over UART interface........................................................................65
9.1.1. Jump to BootLoader command ..................................................................................65
9.1.2. Write APP command..................................................................................................65
9.1.3. Jump to Application command...................................................................................66
9.2. Updating firmware using the SPI interface .....................................................................66

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9.2.1. Boot mode registers....................................................................................................66
9.2.2. Boot mode status register (0x78)................................................................................67
9.2.3. Boot command register (0x7A)..................................................................................68
9.2.4. Boot data register (0x7C)...........................................................................................69
9.2.5. Boot loading sequence................................................................................................70
10. Warranty and support information..........................................................................................71
10.1. Customer service.............................................................................................................71
10.2. Contact directory.............................................................................................................71
10.3. Return procedure.............................................................................................................71
10.3.1. Authorization..............................................................................................................71
10.3.2. Identification and protection ......................................................................................71
10.3.3. Sealing the container..................................................................................................72
10.3.4. Marking......................................................................................................................72
10.4. Warranty..........................................................................................................................72
Appendix A: Installation and operation of NAV-VIEW ...............................................................73
NAV-VIEW Computer requirements.........................................................................................73
Install NAV-VIEW ....................................................................................................................73
Setting up NAV-VIEW..............................................................................................................73
Data recording............................................................................................................................74
Data playback.............................................................................................................................74
Raw data console........................................................................................................................75
Packet statistics view..................................................................................................................76
Unit configuration......................................................................................................................77
Advanced configuration.............................................................................................................78
Bit configuration ........................................................................................................................79
Read unit configuration..............................................................................................................80
Appendix B: Sample Packet-Parser Code......................................................................................84
Overview....................................................................................................................................84
Code listing ................................................................................................................................85
Appendix C: Sample Packet Decoding..........................................................................................91

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About this Manual
The following symbols are used to provide additional information.
X NOTE
Note provides additional information about the topic.
☑EXAMPLE
This symbol indicates an example that will help the reader understand the terminology.
PIMPORTANT
This symbol defines items that have significant meaning to the user
WARNING
The user should pay particular attention to this symbol. It means there is a chance that physical
harm could happen to either the person or the equipment.
This manual uses the following paragraph heading formats:
1 Heading 1
1.1 Heading 2
1.1.1 Heading 3
1.1.1.1 Heading 4
Normal

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1. Introduction
1.1. Manual overview
This manual describes ACEINNA’s IMU383 IMU Inertial Measurement Unit. The IMU383 will
be referred to as “the unit” frequently in this document.
Table 1 below highlights the content in each section and suggests how to use this manual.
Table 1: Manual content
Manual Section
Who Should Read?
Section 1:
Manual Overview
All customers should read Sections 1.1 and 1.2.
Section 2:
Interface
Customers designing the electrical and mechanical interface to
the IMU383 series products should read Section 2.
Section 3:
Theory of Operation
All customers should read Section 3.
Section 4:
SPI Port Interface
Customers designing the software interface to the IMU383
series products SPI Port should review Section 4.
Section 5-8:
UART Port Interface
Customers designing the software Interface To the IMU383
series products UART Port should review Sections 5, 6, 7, 0.
Section 9:
IMU383 Bootloader
Customers that intend to update Aceinna firmware in the unit
should read Section 9.
Section 10:
Warranty and Support Information
All customers should read Section 10.
Appendix A:
Installation and Operation of NAV-
VIEW
All customers should read Appendix A.
Appendix B:
Sample Packet-Parser Code
All customers that intend to create scripts to interface with
serial messages should read Appendix B
Appendix C:
Sample Packet Decoding
All customers that intend to create scripts to interface with
serial messages should read Appendix C
1.2. Overview of the IMU383 Series Inertial Measurement Unit
This manual describes the use of ACEINNA’s IMU383 and is intended to be used as a detailed
technical reference and operating guide. ACEINNA’s IMU383 Series products combine the latest
in high-performance commercial MEMS (Micro-electromechanical Systems) sensors and digital
signal processing techniques to provide a small, cost-effective alternative to existing IMU systems.

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The IMU383 Series is ACEINNA’s fifth generation of MEMS-based Inertial Systems, building on
over a decade of field experience, and encompassing thousands of deployed units and millions of
operational hours in a wide range of land, marine, airborne, and instrumentation applications. It is
designed for OEM applications.
At the core of the IMU383 Series is a trio of rugged 6-DOF (Degrees of Freedom) MEMS inertial
sensor clusters. Each 6-DOF MEMS inertial sensor cluster includes three axes of MEMS angular
rate sensing and three axes of MEMS linear acceleration sensing. These sensors are based on
rugged, field proven silicon bulk micromachining technology. Each sensor within the cluster is
individually factory calibrated for temperature and non-linearity effects during ACEINNA’s
manufacturing and test process using automated thermal chambers and rate tables.
The differentiating feature of the IMU383 Series is the trio of redundant 6-DOF MEMS sensor
clusters. This redundancy has two direct benefits:
1) Combining multiple sensor reading improves the noise characteristics of the output signal
2) Using more than one sensor enables the unit to operate through a single sensor-chip failure by
detecting and voting out the failed part. Failures include stuck or railed readings as well as
sustained inconsistency between the three sensor sets.
Another unique feature of the IMU383 Series is the extensive field configurability of the units. This
field configurability allows the IMU383 Series of Inertial Systems to satisfy a wide range of
applications and performance requirements with a single mass-produced hardware platform. The
basic configurability includes parameters such as baud rate (UART), clock speed (SPI), packet
type, and output data rate, and the advanced configurability includes the defining of custom axes.
The IMU383 Series module is packaged in a lightweight, rugged, unsealed metal enclosure that is
designed for cost-sensitive commercial and OEM applications. The unit can be configured to output
data over a SPI Port or a low level UART serial port. The port choice is user controlled by
grounding the appropriate pin on the connector. ACEINNA’s NAV-VIEW 3.X Windows
application supports using the unit low level UART data port. NAV-VIEW 3.X is a powerful
Windows-based operating tool that provides complete field configuration, diagnostics, charting of
sensor performance, and data logging with playback.

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2. Interface
2.1. Electrical interface
2.1.1. Connector
The unit main connector is a SAMTEC FTM-110-02-F-DV-P. The pin assignment defined in
Figure 1
Figure 1: IMU383 interface connector
Table 2: Interface connector pin definition IMU383
Pin
Pin Description (IMU383)
1
Inertial-Sensor Sampling Indicator (sampling
upon rising edge)
2
Synchronization Input (1 kHz Pulse used to
synchronize SPI Comm). If used, this clock
should be 1kHz +/- 0.1%
3
SPI Clock (SCLK) / UART TX
4
SPI Data Output (MISO) / UART RX
5
SPI Data Input (MOSI)
6
SPI Chip Select (SS)
7
Data Ready (SPI Communication Data Ready) /
SPI-UART Port Select
8
External Reset (NRST)

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9
Reserved –factory use only
10
Power VIN (3-5 VDC)
11
Power VIN (3-5 VDC)
12
Power VIN (3-5 VDC)
13
Power GND
14
Power GND
15
Power GND
16
Reserved –factory use only
17
Reserved
18
Reserved –factory use only
19
Reserved
20
Reserved –factory use only
2.1.2. Power and ground pins
Power is applied to the unit on pins 10 through 15. Pins 13-15 are ground; Pins 10-12 accepts 3 to
5 VDC unregulated input. Note that these are redundant power ground input pairs.
WARNING
Do not reverse the power leads or damage may occur. Do not add greater than 5.5 volts on the
power pins or damage may occur. This system has no reverse voltage or over-voltage protection.
2.1.3. Serial interface
The user can select between SPI and UART communication interface by controlling the logic level
on connector pin 7 at system startup. If pin 7 is left floating, then the unit is configured for SPI
communications on pins 3-6. Pin 7 is set as an output and used as the DATA READY signal for
SPI communications. Additionally, the user can synchronize the output data on the SPI port by
providing a 1 kHz input pulse on Pin 2. For the complete SPI interface definition, please refer to
Section 4.
If the connector pin 7 is grounded, then the unit will configure itself for serial communication via
pins 3 and 4. This is a standard UART asynchronous data port. For the complete UART interface
definition, please refer to following Sections 5, 6, 7, 0.
2.1.3.1. SPI com synchronization input
Pin 2 can be used to force synchronization of unit data processing to external 1 kHz signal. See
Section 4.10 for a more complete description.

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2.1.4. Reserved –factory use only
During normal operation of the unit no connection should be made to the Reserved –factory use
only pins.
2.2. Mechanical interface
The IMU383 mechanical interface is defined by the outline drawing in Figure 2.
Figure 2: Outline drawing
NOTES UNLESS OTHERWISE STATED:
1) MATING CONNECTOR SAMTEC CLM-110-02
2) DIMENSION TO CENTROID OF PIN ONE

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3. Theory of operation
This section of the manual covers detailed theory of operation for the IMU383.
Figure 3 shows the IMU383 Series hardware block diagram. At the core of the IMU383 Series is a
rugged 6-DOF (Degrees of Freedom) MEMS inertial sensor cluster. The 6-DOF MEMS inertial
sensor cluster includes three axes of MEMS angular rate sensing and three axes of MEMS linear
acceleration sensing. These sensors are based on rugged, field proven silicon bulk micromachining
technology.
Each sensor within the cluster is individually factory calibrated using ACEINNA’s automated
manufacturing process. Sensor errors are compensated for temperature bias, scale factor, non-
linearity and misalignment effects using a proprietary algorithm on the data collected during
manufacturing. Accelerometer and rate gyro sensor bias shifts over temperature (-40 0C to +85 0C)
are compensated and verified using calibrated thermal chambers and rate tables.
The 6-DOF inertial sensor cluster data is fed into a high-speed signal processing chain, which
provides the sensor compensation, digital filtering, and sensor fault detection. Measurement data
packets are available at fixed continuous output rates or on a polled basis from the SPI port or the
UART port. The SPI port outputs data via registers, and the user can perform polled reads of each
register, or a block burst read of a set of predefined registers. Output data over the SPI port can be
synchronized to an external 1 kHz pulse. The complete SPI interface is defined in Section 4. The
UART port outputs data packets are asynchronous and defined in following Sections 5, 6, 7, 0.
Figure 3: Series hardware block diagram
Figure 4 shows the software block diagram. The 6-DOF inertial sensor cluster data is fed into a
high speed 200Hz signal processing chain. These 6-DOF signals pass through one or more of the
processing blocks and these signals are converted into output measurement data as shown.
Measurement data packets are available at fixed continuous output rates or on a polled basis.
As shown in the software block diagram, the IMU383 Series has a unit setting and profile block
which configures the unit to user and application specific needs. This feature is one of the more
powerful features in the IMU383 Series architecture as it allows the IMU383 Series to work in a
wide range of commercial applications by settings different modes of operation for the IMU383
Series.

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Figure 4: IMU383 Series software block diagram
3.1. Default coordinate system
The IMU383 Series Inertial System default coordinate frame is shown in Figure 5. As with many
elements of the IMU383 Series, the coordinate system is configurable with either NAV-VIEW or
by sending the appropriate serial commands over the UART port. These configurable elements are
known as Advanced Settings. This section of the manual describes the default coordinate system
settings of the IMU383 Series when it leaves the factory.
Figure 5: IMU383 default coordinate frame

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The axes form an orthogonal SAE right-handed coordinate system. Acceleration is positive when
it is oriented towards the positive side of the coordinate axis. For example, with a IMU383 Series
product sitting on a level table, it will measure zero g along the x- and y-axes and -1 g along the z-
axis. Normal Force acceleration is directed upward, and thus will be defined as negative for the
IMU383 Series z-axis.
The angular rate sensors are aligned with the same axes. The rate sensors measure angular rotation
rate around a given axis. The rate measurements are labeled by the appropriate axis. The direction
of a positive rotation is defined by the right-hand rule. With the thumb of your right hand pointing
along the axis in a positive direction, your fingers curl around in the positive rotation direction. For
example, if the IMU383 Series product is sitting on a level surface and you rotate it clockwise on
that surface, this will be a positive rotation around the z-axis. The x- and y-axis rate sensors would
measure zero angular rates, and the z-axis sensor would measure a positive angular rate.
3.1.1. Advanced settings
The IMU383 Series Inertial Navigation Units have a number of advanced settings that can be
changed. All units support baud rate1, continuous output packet type, output rate, sensor low pass
filtering, and custom axes configuration. The units can be configured using NAV-VIEW, as
described in Appendix A, or directly with serial commands as described in following Sections 5,
6, 7, 0.
3.2. Data processing chain
The unit provides inertial rate and acceleration data in 6-DOF (six degrees of freedom). The unit
signal processing chain consists of the 6-DOF sensor cluster, programmable low-pass filters, and a
signal processing component for sensor error compensation. The unit has a UART input/output
port and a SPI input/output port.
After passing through a digitally controlled programmable low-pass filter, the rate and acceleration
sensor signals are obtained at 200 Hz. The factory calibration data, stored in EEPROM, is used by
the processor to remove temperature bias, misalignment, scale factor errors, and non-linarites from
the sensor data. Additionally, any advanced user settings such as axes rotation are applied to the
IMU data. Finally, sensor fault detection is performed on the sensor signals and the individual
sensor signals are combined to form a signal with reduced noise characteristics.
The 200Hz IMU data is continuously maintained inside the unit and is available at 200Hz on the
SPI output port registers. Digital IMU data is output over the UART port at a selectable fixed rate
(100, 50, 25, 20, 10, 5 or 2 Hz) or on as-requested basis using the GP, ‘Get Packet’ command. The
digital IMU data is available in several measurement packet formats including Scaled Sensor Data
(‘S1’ Packet). In the Scaled Sensor Data (‘S1’ Packet), data is output in scaled engineering units.
See section 6of the manual for full packet descriptions.
3.2.1. Sensor fault detection
New for the IMU383 is the incorporation of triple-redundant accelerometer and gyro sensors, which
enables sensor fault detection. The fault detection routine incorporated into the firmware
continually monitors the output of the three sensor chips. If an outlier is detected in the output, the
1
Note: certain combinations of baud-rate, packet-type, and output data rate are invalid because the time to transmit the data exceeds a
limit on the permissible message length. The IMU383 limits the output packet width to 80% of the time between data packets. For
instance, if the packet isoutput every 10 milliseconds (100 Hz) then the packet width must be less than 8 milliseconds or the combination
is not allowed. This prevents messages from overlapping and causing communication problems. For this reason, 57.6 kbps and higher
baud-rates are suggested.

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routine continues to monitor the sensors until the part is deemed failed. The Fault Tolerant Time
Interval (FTTI) for such a failure is set to 300 msec, however the actual detection time could be
changed if needed. Contact the factory for more information.
3.2.1.1. Configuration field settings for sensor enable and sensor output select
The same mechanism that enables the firmware to vote out a failed or underperforming sensor also
enables the user to turn on or off a sensor chip or exclude an enabled sensor from the output, if
desired (more information in Section 7.1.6 below)
3.2.1.2. User Settings
Selecting which sensors are included in the output can be accomplished using either the write-field
or set-field command (WF or SF) over UART interface. Using the SF command will cause the
setting to take effect immediately, but this value is not stored in non-volatile memory; the WF
command will require a unit-reset before the output is modified but is stored in non-volatile
memory. Several example commands follow:
To get the values for fields 0x42 and 0x43 stored in RAM, use the Get-Field (GF) command:
5555 4746 05 02 0042 0043 a0d0
To set the value for field 0x43 stored in RAM to 0x1 (output sensor #1 only), use the Set-Field (SF)
command:
5555 5346 05 01 0043 0001 236d
To change the value for field 0x42 in EEPROM to 0x1 (enable sensor #1 only), use the Write-Field
(WF) command:
5555 5746 05 01 0042 0001 1b30
Also the same settings can be changed over SPI interface. See Section 4.3 for details.
3.2.2. Advanced settings
The unit advanced settings are described in the table below. All of the advanced settings are
accessible through NAV-VIEW under the Configuration Menu, Unit Configuration settings. For a
full definition of the SPI port please see Section 4.
Table 3: Advanced UART port settings
Setting
Default
Comments
Baud Rate
230400
57600, 115200, and 230400 are available baud rate
Packet Type
S0
S1 also available
Packet Rate
100Hz
This setting sets the rate at which selected Packet Type, packets
are output. If polled mode is desired, then select Quiet. If Quiet is
selected, the unit will only send measurement packets in response
to GP commands.
Orientation
See Figure 5
To configure the axis orientation, select the desired measurement
for each axis: NAV-VIEW will show the corresponding image of
the unit, so it easy to visualize the mode of operation. Refer to
7.1.5 section for twenty four possible orientation settings.

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Setting
Default
Comments
Filter Settings
(unfiltered, 2,
5, 10, 20, 25,
40 50 Hz).
25 Hz
The low pass filters are set to a default of 25 Hz for the
accelerometers, and 25 Hz for the angular rate sensors. There is
one filter setting for all three angular rate sensors. There is one
filter setting for all three accelerometers. Setting either to zero
disables the low-pass filter.
BIT
See Section 8.1.
Note on filter settings
Generally, there is no reason to change the low-pass filter settings on the unit or other IMU383
Series Inertial Systems. However, when an IMU383 Series product is installed in an environment
with a lot of vibration, it can be helpful to reduce the vibration-based signal energy and noise prior
to further processing on the signal. Installing the unit in the target environment and reviewing the
data with NAV-VIEW can be helpful to determine if changing the filter settings would be helpful.
Although the filter settings can be helpful in reducing vibration-based noise inthe signal, low cutoff
filter settings (e.g., 5Hz) also reduce the bandwidth of the signal, which can wash out the signals
containing the dynamics of a target. Therefore, caution should be used when changing the filter
settings.
3.2.3. Built-In test
The unit Built-In Test capability allows users of the unit to monitor health, diagnostic, and system
status information of the unit in real-time. The Built-In Test information consists of a BIT word (2
bytes) transmitted in every measurement packet over UART interface. In addition, there is a
diagnostic packet ‘T0 ’that can be requested via the Get Packet ‘GP ’command which contains a
complete set of status for each hardware and software subsystem in the unit. See Standard UART
Port Commands section for details on the ‘T0 ’packet.
The BIT word, which is contained within each measurement packet, is detailed below. The LSB
(Least Significant Bit) is the Error byte, and the MSB (Most Significant Bit) is a Status byte with
programmable alerts. Internal health and status are monitored and communicated in both hardware
and software. The ultimate indication of a fatal problem is the masterFail flag.
The masterStatus flag is asserted as a result of any associated alert signals. See section 0for details.
The table below shows the definitions for BIT alerts in the unit.
Table 4: Default BIT status definition
BITstatus Field
Bits
Meaning
Category
masterFail
0
0 = normal, 1 = fatal error has occurred
BIT
HardwareError
1
0 = normal, 1= internal hardware error
BIT
Reserved
2
N/A
N/A
softwareError
3
0 = normal, 1 = internal software error
BIT
Reserved
4:7
N/A
N/A

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BITstatus Field
Bits
Meaning
Category
masterStatus
8
0 = nominal, 1 = Alert, Sensor Over Range
Status
hardwareStatus
9
Enabled
Status
Reserved
10
N/A
N/A
softwareStatus
11
Enabled
Status
sensorStatus
12
0 = nominal, 1 = Sensor Over Range
Status
Reserved
13:15
N/A
N/A
sensorStatus indication is always enabled and flag on sensor over-range. The over-range only
applies to the rotational rate sensors. Because instantaneous acceleration levels due to vibration can
exceed the accelerometer sensor range in many applications, none of the IMU383 Series products
trigger over-range on accelerometer readings.

IMU383 Series User’s Manual
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Document Number: 7430-1398-01
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4. SPI port interface definition
The IMU383 has the option to communicate via SPI interface. This section of the user’s manual
defines the unit register map, register control capabilities, and the data register reading and writing
methodologies.
The unit operates as a slave device. The master device must be configured to communicate with
the unit using the following settings:
•Data transferred in 16-bit word-length and MSB-first
•fCLK ≤1.2 MHz
•CPOL = 1 (clock polarity) and CPHA = 1 (clock phase)
Additional operational requirements are described in Section 4.5.
4.1. SPI register map
The table below describes the IMU383 register map. In the following tables the phrasing
“<address1> to <address2>” means all addresses in the inclusive range from <address1> through
<address2> and the phrasing “<read-address>/<write-address>” means that the register is read
from the <read-address> and written to the <write-address>.
NOTE: Sensor data scaling is specific to the message or register being read. Please see scaling
information for each sensordata read operation. Specifically, the sensor data inthe SPIS0_BURST,
the SPI S1_BURST, the UART S0 message and the UART S1 message are scaled differently than
the scaling for reading the individual SPI sensor data registers.
Table 5: SPI register map2
Name
Read/
Write
Register
Address
Default
Function
Reserved
N/A
0x00
N/A
N/A
Fault detection enable
R/W
0x01
0x18
Enabling of fault detection mechanism
functions.
See section 4.4.7.
Fault detection disable
R/W
0x02
0x00
Disabling of fault detection mechanism
functions.
See section 4.4.7.
Fault detect key
R/W
0x03
0x00
Key to enable changing of fault detect
algorithm settings. See section 4.4.7.
Reserved
N/A
0x04 to
0x19
N/A
N/A
Sensor control, chip 1
R/W
0x1A
0xFF (All
ON)
Control of active sensors for Sensor
Chip 1
2
Register and data-packet availability is based on the features of the DMU383ZA..