Precision, Miniature MEMs IMU
ADIS16475
Data Sheet
FEATURES
GENERAL DESCRIPTION
Triaxial, digital gyroscope
±125°/sec, ±500°/sec, ±2000°/sec range models
2°/hr in-run bias stability (ADIS16475-1)
0.15°/√hr angle random walk (ADIS16475-1 and
ADIS16475-2)
±0.1° axis to axis misalignment error
Triaxial, digital accelerometer, ±8 g
3.6 μg in-run bias stability
Triaxial, delta angle and delta velocity outputs
Factory calibrated sensitivity, bias, and axial alignment
Calibration temperature range: −40°C to +85°C
SPI compatible data communications
Programmable operation and control
Automatic and manual bias correction controls
Data ready indicator for synchronous data acquisition
External sync modes: direct, pulse, scaled, and output
On demand self test of inertial sensors
On demand self test of flash memory
Single-supply operation (VDD): 3.0 V to 3.6 V
2000 g mechanical shock survivability
Operating temperature range: −40°C to +105°C
The ADIS16475 is a precision, miniature MEMS inertial measurement unit (IMU) that includes a triaxial gyroscope and a triaxial
accelerometer. Each inertial sensor in the ADIS16475 combines
with signal conditioning that optimizes dynamic performance.
The factory calibration characterizes each sensor for sensitivity,
bias, alignment, linear acceleration (gyroscope bias), and point
of percussion (accelerometer location). As a result, each sensor
has dynamic compensation formulas that provide accurate
sensor measurements over a broad set of conditions.
The ADIS16475 provides a simple, cost effective method for
integrating accurate, multiaxis inertial sensing into industrial
systems, especially when compared with the complexity and
investment associated with discrete designs. All necessary motion
testing and calibration are part of the production process at the
factory, greatly reducing system integration time. Tight orthogonal
alignment simplifies inertial frame alignment in navigation
systems. The serial peripheral interface (SPI) and register
structure provide a simple interface for data collection and
configuration control.
The ADIS16475 is available in a 44-ball, ball grid array (BGA)
package that is approximately 11 mm × 15 mm × 11 mm.
APPLICATIONS
Navigation, stabilization, and instrumentation
Unmanned and autonomous vehicles
Smart agriculture and construction machinery
Factory/industrial automation, robotics
Virtual/augmented reality
Internet of Moving Things
FUNCTIONAL BLOCK DIAGRAM
DR
SELF TEST
RST
VDD
POWER
MANAGEMENT
I/O
OUTPUT
DATA
REGISTERS
TRIAXIAL
GYROSCOPE
TRIAXIAL
ACCELEROMETER
CONTROLLER
TEMPERATURE
SENSOR
CALIBRATION
AND
FILTERS
GND
CS
SCLK
SPI
USER
CONTROL
REGISTERS
DIN
DOUT
ADIS16475
SYNC
15436-001
CLOCK
Figure 1.
Rev. D
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ADIS16475
Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
Device Configuration ................................................................ 16
Applications ...................................................................................... 1
User Register Memory Map.......................................................... 17
General Description ......................................................................... 1
User Register Defintions ............................................................... 19
Functional Block Diagram .............................................................. 1
Gyroscope Data .......................................................................... 19
Revision History ............................................................................... 2
Delta Angles ................................................................................ 22
Specifications .................................................................................... 3
Delta Velocity ............................................................................. 24
Timing Specifications .................................................................. 5
Calibration .................................................................................. 25
Absolute Maximum Ratings ....................................................... 7
Applications Information ............................................................. 32
Thermal Resistance ...................................................................... 7
Assembly and Handling Tips ................................................... 32
ESD Caution.................................................................................. 7
Power Supply Considerations .................................................. 33
Pin Configuration and Function Descriptions ............................ 8
Serial Port Operation ................................................................. 33
Typical Performance Characteristics ........................................... 10
Digital Resolution of Gyroscopes and Accelerometers ........ 33
Theory of Operation ...................................................................... 12
Evaluation Tools......................................................................... 34
Introduction ................................................................................ 12
Tray Drawing .............................................................................. 36
Inertial Sensor Signal Chain ..................................................... 12
Packaging and Ordering Information ......................................... 37
Register Structure ....................................................................... 13
Outline Dimensions ................................................................... 37
Serial Peripheral Interface (SPI) ............................................... 14
Ordering Guide .......................................................................... 37
Data Ready (DR) ........................................................................ 14
Reading Sensor Data .................................................................. 15
REVISION HISTORY
4/2020—Rev. C to Rev. D
Change to Logic Inputs Parameter, Table 1 ................................. 4
Changes to Endnote 1, Table 3 ....................................................... 7
4/2019—Rev. B to Rev. C
Changes to Serial Peripheral Interface (SPI) Section ................ 14
Changes to Figure 32 ..................................................................... 15
Changes to Table 10 and Gyroscope Data Section .................... 19
Changes to Acceleration Data Section ........................................ 20
Added Accelerometer Data Formatting Section ........................ 21
Deleted Accelerometer Resolution Section ................................ 21
Added Serial Port Operation Section, Maximum Throughput
Section, Serial Port SCLK Underrun/Overrun Conditions Section,
and Digital Resolution of Gyroscopes and Accelerometers Section
.....................................................................................................................33
Moved Gyroscope Data Width (Digital Resolution) Section... 33
Moved Accelerometer Data Width (Digital Resolution) Section . 33
Moved Figure 52 and Figure 53.................................................... 35
Added Tray Drawing Section ....................................................... 36
Added Figure 54 ............................................................................. 36
1/2019—Rev. A to Rev. B
Changes to Table 1 ........................................................................... 3
Changes to Table 2 ........................................................................... 5
Changes to Figure 5 ..........................................................................6
Changes to Figure 11 ..................................................................... 10
Added Figure 12 and Figure 13; Renumbered Sequentially..... 10
Added Figure 14, Figure 15, Figure 16, and Figure 17 .............. 11
Changes to Figure 18, Figure 19, and Figure 20 ........................ 12
Changes to Figure 22 and Figure 23 ............................................ 13
Added Gyroscope Data Width (Digital Resolution) Section ... 19
Changes to Gyroscope Measurement Range/Scale Factor Section,
Table 11, Table 12, Table 13, Table 17, Table 21, and Table 25 20
Added Accelerometer Data Width (Digital Resolution)
Section .............................................................................................. 21
Change to Calibration, Accelerometer Bias (XA_BIAS_LOW
and XA_BIAS_HIGH) Section..................................................... 26
Change to Filter Control Register (FILT_CTRL) Section ........ 27
Changes to Direct Sync Mode Section and to Pulse Sync Mode
Section .............................................................................................. 28
Changes to Sensor Self Test Section ............................................ 30
11/2017—Rev. 0 to Rev. A
Changes to Table 1 ............................................................................3
Deleted Endnote 1, Table 1; Renumbered Sequentially...............4
Added Endnote 2, Table 1; Renumbered Sequentially ................4
10/2017—Revision 0: Initial Version
Rev. D | Page 2 of 37
Data Sheet
ADIS16475
SPECIFICATIONS
Case temperature (TC) = 25°C, VDD = 3.3 V, angular rate = 0°/sec, dynamic range = ±2000°/sec ± 1 g, unless otherwise noted.
Table 1.
Parameter
GYROSCOPES
Dynamic Range
Sensitivity
Error over Temperature
Repeatability 1
Misalignment Error
Nonlinearity 2
Bias
Repeatability1
In-Run Bias Stability
Angular Random Walk
Error over Temperature
Linear Acceleration Effect
Vibration Rectified Error (VRE)
Output Noise
Rate Noise Density
3 dB Bandwidth
Sensor Resonant Frequency
ACCELEROMETERS 3
Dynamic Range
Sensitivity
Error over temperature
Repeatability1
Misalignment Error
Nonlinearity
Bias
Repeatability1
In-Run Bias Stability
Velocity Random Walk
Error over Temperature
Test Conditions/Comments
Min
ADIS16475-1
ADIS16475-2
ADIS16475-3
ADIS16475-1, 16-bit
ADIS16475-2, 16-bit
ADIS16475-3, 16-bit
ADIS16475-1, 32-bit
ADIS16475-2, 32-bit
ADIS16475-3, 32-bit
−40°C ≤ TC ≤ +85°C, 1 σ
−40°C ≤ TC ≤ +85°C, 1 σ
Axis to axis, −40°C ≤ TC ≤ +85°C, 1 σ
ADIS16475-1, full scale (FS) = 125°/sec
ADIS16475-2, FS = 500°/sec
ADIS16475-3, FS = 2000°/sec
±125
±500
±2000
Typ
Max
Unit
160
40
10
10,485,760
2,621,440
655,360
±0.3
±0.3
±0.1
0.2
0.2
0.25
°/sec
°/sec
°/sec
LSB/°/sec
LSB/°/sec
LSB/°/sec
LSB/°/sec
LSB/°/sec
LSB/°/sec
%
%
Degrees
% FS
% FS
% FS
0.7
2
2.5
7
0.15
0.15
0.3
±0.2
0.01
0.0005
0.07
0.08
0.17
0.003
0.003
0.007
550
66
°/sec
°/hr
°/hr
°/hr
°/√hr
°/√hr
°/√hr
°/sec
°/sec/g
°/sec/g2
°/sec rms
°/sec rms
°/sec rms
°/sec/√Hz rms
°/sec/√Hz rms
°/sec/√Hz rms
Hz
kHz
32-bit data format
−40°C ≤ TC ≤ +85°C, 1 σ
−40°C ≤ TC ≤ +85°C, 1 σ
Axis to axis, −40°C ≤ TC ≤ +85°C, 1 σ
Best fit straight line, ±2 g
Best fit straight line, ±8 g, x-axis
Best fit straight line, ±8 g, y-axis and z-axis
262,144,000
±0.1
±0.1
±0.05
0.25
0.5
1.5
g
LSB/g
%
%
Degrees
% FS
% FS
% FS
−40°C ≤ TC ≤ +85°C, 1 σ
1σ
1σ
−40°C ≤ TC ≤ +85°C, 1 σ
1.4
3.6
0.012
±1
mg
μg
m/sec/√hr
mg
−40°C ≤ TC ≤ +85°C, 1 σ
ADIS16475-1, 1 σ
ADIS16475-2, 1 σ
ADIS16475-3, 1 σ
ADIS16475-1, 1 σ
ADIS16475-2, 1 σ
ADIS16475-3, 1 σ
−40°C ≤ TC ≤ +85°C, 1 σ
Any direction, 1 σ
Random vibration, 2 grms, 50 Hz to 2 kHz
ADIS16475-1, 1 σ, no filtering
ADIS16475-2, 1 σ, no filtering
ADIS16475-3, 1 σ, no filtering
ADIS16475-1, f = 10 Hz to 40 Hz
ADIS16475-2, f = 10 Hz to 40 Hz
ADIS16475-3, f = 10 Hz to 40 Hz
Each axis
±8
Rev. D | Page 3 of 37
ADIS16475
Parameter
Output Noise
Noise Density
3 dB Bandwidth
Sensor Resonant Frequency
TEMPERATURE SENSOR
Scale Factor
LOGIC INPUTS 4
Input Voltage
High, VIH
Low, VIL
RST Pulse Width
Input Current
Logic 1, IIH
Logic 0, IIL
All Pins Except RST
RST Pin
Input Capacitance, CIN
DIGITAL OUTPUTS
Output Voltage
High, VOH
Low, VOL
FLASH MEMORY
Data Retention 6
FUNCTIONAL TIMES 7
Power-On Start-Up Time
Reset Recovery Time 8
Factory Calibration Restore
Flash Memory Backup
Flash Memory Test Time
Self Test Time 9
CONVERSION RATE
Initial Clock Accuracy
Sync Input Clock
POWER SUPPLY, VDD
Power Supply Current 10
Data Sheet
Test Conditions/Comments
No filtering
f = 10 Hz to 40 Hz, no filtering
Min
Y-axis and z-axis
X-axis
Typ
0.6
23
600
2.4
2.2
Output = 0x0000 at 0°C (±5°C)
0.1
Max
°C/LSB
2.0
0.8
V
V
µs
10
µA
10
µA
mA
pF
1
VIH = 3.3 V
VIL = 0 V
0.33
10
ISOURCE = 0.5 mA
ISINK = 2.0 mA
Endurance 5
TJ = 85°C
Time until data is available
2.4
0.4
10000
20
252
193
142
72
32
14
2000
3
GLOB_CMD, Bit 7 = 1 (see Table 113)
GLOB_CMD, Bit 1 = 1 (see Table 113)
GLOB_CMD, Bit 3 = 1 (see Table 113)
GLOB_CMD, Bit 4 = 1 (see Table 113)
GLOB_CMD, Bit 2 = 1 (see Table 113)
Operating voltage range
Normal mode, VDD = 3.3 V
1.9
3.0
44
Unit
mg rms
μg/√Hz rms
Hz
kHz
kHz
2.1
3.6
55
V
V
Cycles
Years
ms
ms
ms
ms
ms
ms
SPS
%
kHz
V
mA
Bias repeatability provides an estimate for long-term drift in the bias, as observed during 500 hours of high temperature operating life (HTOL) at 105°C.
This measurement is based on the deviation from a best fit linear model.
All specifications associated with the accelerometers relate to the full-scale range of ±8 g, unless otherwise noted.
4
The digital input/output signals use a 3.3 V system.
5
Endurance is qualified as per JEDEC Standard 22, Method A117, measured at −40°C, +25°C, +85°C, and +125°C.
6
The data retention specification assumes a junction temperature (TJ) of 85°C per JEDEC Standard 22, Method A117. Data retention lifetime decreases with TJ.
7
These times do not include thermal settling and internal filter response times, which may affect overall accuracy.
8
The RST line must be in a low state for at least 10 μs to ensure a proper reset initiation and recovery.
9
The self test time can extend when using external clock rates lower than 2000 Hz.
10
Power supply current transients can reach 100 mA during initial startup or reset recovery.
1
2
3
Rev. D | Page 4 of 37
Data Sheet
ADIS16475
TIMING SPECIFICATIONS
TA = 25°C, VDD = 3.3 V, unless otherwise noted.
Table 2.
Parameter
fSCLK
tSTALL
tREADRATE
tCS
Description
Serial clock
Stall period between data
Read rate
Chip select to SCLK edge
tDAV
tDSU
tDHD
tSCLKR, tSCLKF
tDR, tDF
tSFS
t1
DOUT valid after SCLK edge
DIN setup time before SCLK rising edge
DIN hold time after SCLK rising edge
SCLK rise/fall times
DOUT rise/fall times
CS high after SCLK edge
Input sync positive pulse width; pulse sync mode, MSC_CTRL =
101 (binary, see Table 105)
Input sync to data ready valid transition
Direct sync mode, MSC_CTRL = 001 (binary, see Table 105)
Pulse sync mode, MSC_CTRL = 101 (binary, see Table 105)
Data invalid time
Input sync period 2
tSTDR
tNV
t2
1
2
Min
0.1
16
24
200
Normal Mode
Typ
Max
2
Burst Read Mode
Min 1
Typ
Max
0.1
1
N/A
200
25
25
25
50
25
50
5
5
12.5
12.5
5
5
0
5
12.5
12.5
0
5
256
256
20
256
256
20
477
477
Timing Diagrams
tSCLKR
tSCLKF
tCS
tSFS
1
2
3
4
5
6
15
16
SCLK
tDAV
DB14
tDR
DB13
tDSU
DIN
R/W
A6
DB12
DB11
tDHD
A5
DB10
DB2
DB1
LSB
tDF
A4
A3
A2
D2
D1
15436-002
MSB
DOUT
LSB
Figure 2. SPI Timing and Sequence Diagram
tREADRATE
tSTALL
15436-003
CS
SCLK
Figure 3. Stall Time and Data Rate Timing Diagram
Rev. D | Page 5 of 37
ns
ns
ns
ns
ns
ns
µs
µs
µs
µs
µs
N/A means not applicable.
This specification is rounded up from the cycle time that comes from the maximum input clock frequency (2100 Hz).
CS
Unit
MHz
µs
µs
ns
ADIS16475
Data Sheet
t2
tSTDR
t1
DR
tNV
15436-004
SYNC
Figure 4. Input Clock Timing Diagram, Pulse Sync Mode, Register MSC_CTRL, Bits[4:2] = 101 (Binary)
t2
t1
SYNC
tNV
tSTDR
15436-005
DR
Figure 5. Input Clock Timing Diagram, Direct Sync Mode, Register MSC_CTRL, Bits[4:2] = 001 (Binary)
Rev. D | Page 6 of 37
Data Sheet
ADIS16475
ABSOLUTE MAXIMUM RATINGS
THERMAL RESISTANCE
Table 3.
Parameter
Mechanical Shock Survivability
Any Axis, Unpowered
Any Axis, Powered
VDD to GND
Digital Input Voltage to GND
Digital Output Voltage to GND
Calibration Temperature Range
Operating Temperature Range
Storage Temperature Range1
Barometric Pressure
1
Thermal performance is directly linked to printed circuit board
(PCB) design and operating environment. Careful attention to
PCB thermal design is required.
Rating
2000 g
2000 g
−0.3 V to +3.6 V
−0.3 V to VDD + 0.2 V
−0.3 V to VDD + 0.2 V
−40°C to +85°C
−40°C to +105°C
−65°C to +150°C
2 bar
The ADIS16475 is a multichip module that includes many
active components. The values in Table 4 identify the thermal
response of the hottest component inside of the ADIS16475,
with respect to the overall power dissipation of the module.
This approach enables a simple method for predicting the
temperature of the hottest junction, based on either ambient or
case temperature.
Extended exposure to temperatures that are lower than −40°C or higher
than +105°C may adversely affect the accuracy of the factory calibration.
Stresses at or above those listed under Absolute Maximum
Ratings may cause permanent damage to the product. This is a
stress rating only; functional operation of the product at these
or any other conditions above those indicated in the
operational section of this specification is not implied.
Operation beyond the maximum operating conditions for
extended periods may affect product reliability.
For example, when the ambient temperature is 70°C, the
hottest junction temperature (TJ) inside of the ADIS16475 is
76.7°C.
TJ = θJA × VDD × IDD + 70°C
TJ = 158.2°C/W × 3.3 V × 0.044 A + 70°C
TJ = 93°C
Table 4. Package Characteristics
Package Type
ML-44-13
θJA1
158.2°C/W
θJC2
106.1°C/W
Device Weight
1.3 g
θJA is the natural convection junction to ambient thermal resistance
measured in a one cubic foot sealed enclosure.
θJC is the junction to case thermal resistance.
3
Thermal impedance values come from direct observation of the hottest
temperature inside of the ADIS16475 when it is attached to an FR4-08 PCB
that has two metal layers and has a thickness of 0.063 inches.
1
2
ESD CAUTION
Rev. D | Page 7 of 37
ADIS16475
Data Sheet
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
ADIS16475
A
B
C
D
E
F
G
H
J
K
1
2
PIN A1
3
4
5
6
7
PIN K8
Figure 7. Pin Assignments, Package Level View
Figure 6. Pin Assignments, Bottom View
Table 5. Pin Function Descriptions
Pin No.
A1
A2
A3
A4
A5
A6
A7
A8
B3
B4
B5
B6
C2
C3
C6
C7
D3
D6
E2
E3
E6
E7
F1
F3
F6
F8
G2
G3
G6
G7
H1
H3
H6
H8
Mnemonic
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
GND
DNC
GND
VDD
GND
VDD
GND
VDD
GND
GND
GND
RST
GND
GND
GND
CS
DIN
GND
VDD
DOUT
SCLK
GND
15436-007
BOTTOM VIEW OF PACKAGE
15436-006
PIN A8
8
Type
Supply
Supply
Supply
Supply
Supply
Supply
Supply
Supply
Supply
Supply
Supply
Supply
Supply
Not applicable
Supply
Supply
Supply
Supply
Supply
Supply
Supply
Supply
Supply
Input
Supply
Supply
Supply
Input
Input
Supply
Supply
Output
Input
Supply
Rev. D | Page 8 of 37
Description
Power Ground
Power Ground
Power Ground
Power Ground
Power Ground
Power Ground
Power Ground
Power Ground
Power Ground
Power Ground
Power Ground
Power Ground
Power Ground
Do Not Connect
Power Ground
Power Supply
Power Ground
Power Supply
Power Ground
Power Supply
Power Ground
Power Ground
Power Ground
Reset
Power Ground
Power Ground
Power Ground
SPI, Chip Select
SPI, Data Input
Power Supply
Power Supply
SPI, Data Output
SPI, Serial Clock
Power Ground
Data Sheet
Pin No.
J2
J3
J4
J5
J6
J7
K1
K3
K6
K8
ADIS16475
Mnemonic
GND
SYNC
VDD
VDD
DR
GND
GND
GND
VDD
GND
Type
Supply
Input
Supply
Supply
Output
Supply
Supply
Supply
Supply
Supply
Rev. D | Page 9 of 37
Description
Power Ground
Sync (External Clock)
Power Supply
Power Supply
Data Ready
Power Ground
Power Ground
Power Ground
Power Supply
Power Ground
ADIS16475
Data Sheet
TYPICAL PERFORMANCE CHARACTERISTICS
X-AXIS
Y-AXIS
Z-AXIS
X-AXIS
Y-AXIS
Z-AXIS
ALLAN DEVIATION (µg)
100
10
0.1
1
10
100
1000
10000 100000
INTEGRATION PERIOD (Seconds)
0.001
GYROSCOPE SENSITIVITY ERROR (%)
1
1
10
100
1000
10000 100000
INTEGRATION PERIOD (Seconds)
10000 100000
0.3
0.2
0.1
µ + 1σ
0
–0.1
–0.2
µ – 1σ
µ
–0.3
–0.4
–40
–20
0
20
40
60
80
100
AMBIENT TEMPERATURE (°C)
0.5
1000
GYROSCOPE SENSITIVITY ERROR (%)
X-AXIS
Y-AXIS
Z-AXIS
100
10
1
0.01
0.1
1
10
100
1000
10000 100000
INTEGRATION PERIOD (Seconds)
Figure 10. Gyroscope Allan Deviation, TC = 25°C, ADIS16475-3
0.4
0.3
0.2
µ + 1σ
0.1
0
–0.1
µ
–0.2
µ – 1σ
–0.3
–0.4
–0.5
–60
15436-010
ALLAN DEVIATION (Degrees/hour)
1000
Figure 12. ADIS16475-1 Gyroscope Sensitivity Error vs. Ambient Temperature
Figure 9. Gyroscope Allan Deviation vs. TC = 25°C, ADIS16475-2
0.1
0.001
100
0.4
–0.5
–60
15436-009
ALLAN DEVIATION (Degrees/hour)
10
0.1
10
0.5
X-AXIS
Y-AXIS
Z-AXIS
0.01
1
Figure 11. Accelerometer Allan Deviation, TC = 25°C
100
0.1
0.001
0.1
INTEGRATION PERIOD (Seconds)
Figure 8. Gyroscope Allan Deviation, TC = 25°C, ADIS16475-1
1000
0.01
15436-112
0.01
–40
–20
0
20
40
60
AMBIENT TEMPERATURE (°C)
80
100
15436-113
0.1
0.001
15436-011
1
15436-008
ALLAN DEVIATION (Degrees/hour)
1000
Figure 13. ADIS16475-2 Gyroscope Sensitivity Error vs. Ambient Temperature
Rev. D | Page 10 of 37
ADIS16475
0.5
0.4
0.4
GYROSCOPE BIAS ERROR (°/sec)
0.5
0.3
0.2
0.1
0
µ + 1σ
–0.1
–0.2
µ
–0.3
µ – 1σ
–0.4
–20
0
20
40
60
80
100
Figure 14. ADIS16475-3 Gyroscope Sensitivity Error vs. Ambient Temperature
0
–0.1
µ
–0.2
µ – 1σ
–0.3
–0.5
–60
0.5
0.4
0.4
0.2
µ + 1σ
0.1
0
–0.1
µ – 1σ
µ
–0.2
–0.3
–20
0
20
40
60
80
100
Figure 16. ADIS16475-2 Gyroscope Bias Error vs. Ambient Temperature
0.5
0.3
–40
AMBIENT TEMPERATURE (°C)
GYROSCOPE BIAS ERROR (°/sec)
GYROSCOPE BIAS ERROR (°/sec)
0.1
15436-116
–40
AMBIENT TEMPERATURE (°C)
0.3
0.2
µ + 1σ
0.1
0
µ
–0.1
µ – 1σ
–0.2
–0.3
–0.4
–0.4
–40
–20
0
20
40
60
AMBIENT TEMPERATURE (°C)
80
100
–0.5
–60
15436-115
–0.5
–60
µ + 1σ
0.2
Figure 15. ADIS16475-1 Gyroscope Bias Error vs. Ambient Temperature
–40
–20
0
20
40
60
AMBIENT TEMPERATURE (°C)
80
100
15436-117
–0.5
–60
0.3
–0.4
15436-114
GYROSCOPE SENSITIVITY ERROR (%)
Data Sheet
Figure 17. ADIS16475-3 Gyroscope Bias Error vs. Ambient Temperature
Rev. D | Page 11 of 37
ADIS16475
Data Sheet
THEORY OF OPERATION
INTRODUCTION
External Clock Options
When using the factory default configuration for all user
configurable control registers, the ADIS16475 initializes itself
and automatically starts a continuous process of sampling,
processing, and loading calibrated sensor data into its output
registers at a rate of 2000 SPS.
The ADIS16475 provides three different modes of operation
that support the device using an external clock to control the
internal processing rate (fSM in Figure 19 and Figure 20) through
the SYNC pin. The MSC_CTRL register (see Table 105) provides
the configuration options for these external clock modes in
Bits[4:2].
MEMS
SENSORS
BARTLETT
WINDOW
FIR
FILTER
AVERAGING
DECIMATING
FILTER
CALIBRATION
OUTPUT
DATA
REGISTERS
Gyroscope Data Sampling
ADC
TO
BARTLETT
WINDOW
FIR FILTER
fSG = 4100Hz
fSM = 2000Hz
15436-015
The three gyroscopes produce angular rate measurements around
three orthogonal axes (x, y, and z). Figure 19 shows the data
sampling plan for each gyroscope when the ADIS16475 operates
in internal clock mode (default, see Register MSC_CTRL,
Bits[4:2] in Table 105). Each gyroscope has an analog-to-digital
converter (ADC) and sample clock (fSG) that drives data sampling
at a rate of 4100 Hz (±5%). The internal processor reads and
processes this data from each gyroscope at a rate of 2000 Hz (fSM).
INTERNAL
DATA
REGISTER
Figure 19. Gyroscope Data Sampling
Accelerometer Data Sampling
The three accelerometers produce linear acceleration measurements
along the same orthogonal axes (x, y, and z) as the gyroscopes.
Figure 20 shows the data sampling plan for each accelerometer
when the ADIS16475 operates in internal clock mode (default,
see Register MSC_CTRL, Bits[4:2] in Table 105).
ADC
1 2
a(n)
2n= 1
÷2
2 × fSM = 4000Hz
Figure 20. Accelerometer Data Sampling
TO
BARTLETT
WINDOW
FIR FILTER
15436-016
MEMS
ACCELEROMETER
The inertial sensor calibration function for the gyroscopes and the
accelerometers has two components: factory calibration and
user calibration (see Figure 21).
FROM
BARTLETT
WINDOW
FIR FILTER
FACTORY
CALIBRATION
USER
CALIBRATION
TO
AVERAGING
DECIMATING
FILTER
Figure 21. Inertial Sensor Calibration Processing
The factory calibration of the gyroscope applies the following
correction formulas to the data of each gyroscope:
Figure 18. Signal Processing Diagram, Inertial Sensors
MEMS
GYROSCOPE
Inertial Sensor Calibration
15436-014
Figure 18 provides the basic signal chain for the inertial sensors
in the ADIS16475. This signal chain produces an update rate
of 2000 SPS in the output data registers when it operates in
internal clock mode (default, see Register MSC_CTRL, Bits[4:2]
in Table 105).
15436-017
INERTIAL SENSOR SIGNAL CHAIN
ω XC m11 m12
ωYC = m21 m22
ωZC m31 m32
l11 l12
l21 l22
l31 l32
m13 ω X bX
m23 × ωY + bY +
m33 ωZ bZ
l13 a XC
l23 × aYC
l33 aZC
where:
ωXC, ωYC, and ωZC are the gyroscope outputs (post calibration).
m11, m12, m13, m21, m22, m23, m31, m32, and m33 provide scale and
alignment correction.
ωX, ωY, and ωZ are the gyroscope outputs (precalibration).
bX, bY, and bZ provide bias correction.
l11, l12, l13, l21, l22, l23, l31, l32, and l33 provide linear g correction
aXC, aYC, and aZC are the accelerometer outputs (post calibration).
All of the correction factors in this relationship come from
direct observation of the response of each gyroscope at multiple
temperatures over the calibration temperature range (−40°C ≤
TC ≤ +85°C). These correction factors are stored in the flash
memory bank, but they are not available for observation or
configuration. Register MSC_CTRL, Bit 7 (see Table 105)
provides the only user configuration option for the factory
calibration of the gyroscopes: an on/off control for the linear g
compensation. See Figure 44 for more details on the user
calibration options available for the gyroscopes.
Rev. D | Page 12 of 37
Data Sheet
ADIS16475
p32
FROM
MEMS
SENSOR
2
p13 ω XC
2
p23 × ω YC
0 ω2ZC
1 N
ω(n)
Nn = 1
1 N
ω(n)
Nn = 1
TO
FACTORY
CALIBRATION
Figure 22. Bartlett Window FIR Filter Signal Path
where:
aXC, aYC, and aZC are the accelerometer outputs (post calibration).
m11, m12, m13, m21, m22, m23, m31, m32, and m33 provide scale and
alignment correction.
aX, aY, and aZ are the accelerometer outputs (precalibration).
bX, bY, and bZ provide bias correction.
p12, p13, p21, p23, p31, and p32 provide a point of percussion
alignment correction (see Figure 47).
ω2XC, ω2YC, and ω2ZC are the square of the gyroscope outputs
(post calibration).
All of the correction factors in this relationship come from
direct observation of the response of each accelerometer at
multiple temperatures over the calibration temperature range
(−40°C ≤ TC ≤ +85°C). These correction factors are stored
in the flash memory bank, but they are not available for
observation or configuration. MSC_CTRL, Bit 6 (see Table 105)
provides the only user configuration option for the factory
calibration of the accelerometers: an on/off control for the point of
percussion, alignment function. See Figure 45 for more details
on the user calibration options available for the accelerometers.
Averaging/Decimating Filter
The second digital filter averages multiple samples together to
produce each register update. In this type of filter structure, the
number of samples in the average is equal to the reduction in
the update rate for the output data registers. The DEC_RATE
register (see Table 109) provides the configuration controls for
this filter.
FROM
USER
CALIBRATION
1 N
ω(n)
N nΣ
=1
÷N
TO OUTPUT
REGISTERS
Figure 23. Averaging/Decimating Filter Diagram
REGISTER STRUCTURE
All communication between the ADIS16475 and an external
processor involves either reading the contents of an output
register or writing configuration/command information to a
control register. The output data registers include the latest
sensor data, error flags, and identification information. The
control registers include sample rate, filtering, calibration, and
diagnostic options. Each user accessible register has two bytes
(upper and lower), each of which has its own unique address.
See Table 8 for a detailed list of all user registers, along with
their addresses.
TRIAXIAL
GYROSCOPE
TRIAXIAL
ACCELLEROMETER
TEMPERATURE
SENSOR
SENSOR
SIGNAL
PROCESSING
OUTPUT
REGISTERS
CONTROLLER
CONTROL
REGISTERS
Figure 24. Basic Operation of the ADIS16475
Rev. D | Page 13 of 37
15436-020
p12
0
15436-019
0
p21
p31
m13 a X bX
m23 × aY + bY +
m33 aZ bZ
The Bartlett window finite impulse response (FIR) filter
(see Figure 22) contains two averaging filter stages in a cascade
configuration. The FILT_CTRL register (see Table 101) provides
the configuration controls for this filter.
SPI
a XC m11 m12
aYC = m21 m22
a m31 m32
ZC
Bartlett Window FIR Filter
15436-018
The factory calibration of the accelerometer applies the following
correction formulas to the data of each accelerometer:
ADIS16475
Data Sheet
DATA READY (DR)
The SPI provides access to the user registers (see Table 8).
Figure 25 shows the most common connections between the
ADIS16475 and a SPI master device, which is often an embedded
processor that has a SPI-compatible interface. In this example,
the SPI master uses an interrupt service routine to collect data
every time the data ready (DR) signal pulses.
The factory default configuration provides users with a DR
signal on the DR pin (see Table 5), which pulses when the output
data registers are updating. Connect the DR pin to a pin on the
embedded processor, which triggers data collection, on the
second edge of this pulse. The MSC_CTRL register, Bit 0 (see
Table 105), controls the polarity of this signal. In Figure 26,
Register MSC_CTRL, Bit 0 = 1, which means that data
collection must start on the rising edges of the DR pulses.
Additional information on the ADIS16475 SPI can be found in
the Serial Port Operation section of this data sheet.
I/O LINES ARE COMPATIBLE WITH
3.3V LOGIC LEVELS
+3.3V
VDD
15436-022
SERIAL PERIPHERAL INTERFACE (SPI)
DR
ACTIVE
INACTIVE
Figure 26. Data Ready When Register MSC_CTRL, Bit 0 = 1 (Default)
SCLK
SCLK
MOSI
DIN
MISO
DOUT
DR
15436-021
IRQ
During the start-up and reset recovery processes, the DR signal
may exhibit some transient behavior before data production
begins. Figure 27 shows an example of the DR behavior during
startup, and Figure 28 and Figure 29 provide examples of the
DR behavior during recovery from reset commands.
ADIS16475
TIME THAT VDD > 3V
VDD
Figure 25. Electrical Connection Diagram
PULSING INDICATES
DATA PRODUCTION
Table 6. Generic SPI Master Pin Names and Functions
Mnemonic
SS
SCLK
MOSI
MISO
IRQ
Function
Slave select
Serial clock
Master output, slave input
Master input, slave output
Interrupt request
DR
START-UP TIME
Figure 27. Data Ready Response During Startup
SOFTWARE RESET COMMAND
GLOB_CMD[7] = 1
Embedded processors typically use control registers to configure
their serial ports for communicating with SPI slave devices such
as the ADIS16475. Table 7 provides a list of settings that describe
the SPI protocol of the ADIS16475. The initialization routine
of the master processor typically establishes these settings using
firmware commands to write them into the control registers.
DR PULSING
RESUMES
DR
RESET RECOVERY TIME
Figure 28. Data Ready Response During Reset
(Register GLOB_CMD, Bit 7 = 1) Recovery
Table 7. Generic Master Processor SPI Settings
Processor Setting
Master
SCLK ≤ 2 MHz1
SPI Mode 3
MSB First Mode
16-Bit Mode
1
15436-023
CS
Description
ADIS16475 operates as slave
Maximum serial clock rate
CPOL = 1 (polarity), CPHA = 1 (phase)
Bit sequence, see Figure 30 for coding
Shift register and data length
15436-024
SS
RST PIN
RELEASED
RST
DR PULSING
RESUMES
DR
A burst mode read requires this value to be ≤1 MHz (see Table 2 for more
information).
RESET RECOVERY TIME
Figure 29. Data Ready Response During Reset (RST = 0) Recovery
Rev. D | Page 14 of 37
15436-025
SYSTEM
PROCESSOR
SPI MASTER
Data Sheet
ADIS16475
CS
DIN
R/W
D15
DOUT
A6
A5
A4
A3
A2
A1
A0
DC7
D14
D13
D12
D11
D10
D9
D8
D7
DC6 DC5
D6
DC4
D5
DC3 DC2
D4
D3
R/W
DC1 DC0
D2
D1
D0
D15
A6
A5
D14
D13
NOTES
1. DOUT BITS ARE PRODUCED ONLY WHEN THE PREVIOUS 16-BIT DIN SEQUENCE STARTS WITH R/W = 0.
2. WHEN CS IS HIGH, DOUT IS IN A THREE-STATE, HIGH IMPEDANCE MODE, WHICH ALLOWS MULTIFUNCTIONAL USE OF THE LINE
FOR OTHER DEVICES.
15436-026
SCLK
Figure 30. SPI Communication Bit Sequence
CS
1
2
3
11
SCLK
0x6800
DIAG_STAT
DOUT
XGYRO_OUT
15436-027
DIN
CHECKSUM
Figure 31. Burst Read Sequence
CS
SCLK
DIN
DOUT HIGH-Z
HIGH-Z
DOUT = 0100 0000 0101 1011 = 0x405B = 16475 (PROD_ID)
15436-028
DIN = 0x7200 = 0111 0010 0000 0000
Figure 32. SPI Signal Pattern Showing a Read of the PROD_ID Register
Burst Read Function
Reading a single register requires two 16-bit cycles on the SPI:
one to request the contents of a register and another to receive
those contents. The 16-bit command code (see Figure 30) for a
read request on the SPI has three parts: the read bit (R/W = 0),
either address of the register, [A6:A0], and eight don’t care bits,
[DC7:DC0]. Figure 33 shows an example that includes two register
reads in succession. This example starts with DIN = 0x0C00 to
request the contents of the Z_GYRO_LOW register, and
follows with 0x0E00 to request the contents of the Z_GYRO_OUT
register. The sequence in Figure 33 also shows full duplex mode
of operation, which means that the ADIS16475 can receive
requests on DIN while also transmitting data out on DOUT
within the same 16-bit SPI cycle.
The burst read function provides a way to read a batch of
output data registers, using a continuous stream of bits, at a
rate of up to 1 MHz (SCLK). This method does not require a
stall time between each 16-bit segment (see Figure 3). As shown
in Figure 31, start this mode by setting DIN = 0x6800, and then
read each of the registers in the sequence out of DOUT while
keeping CS low for the entire 176-bit sequence.
DIN
DOUT
0x0C00
0x0E00
NEXT
ADDRESS
Z_GYRO_LOW
Z_GYRO_OUT
15436-029
READING SENSOR DATA
Figure 33. SPI Read Example
Figure 32 provides an example of the four SPI signals when
reading the PROD_ID register (see Table 121) in a repeating
pattern. This pattern can be helpful when troubleshooting the
SPI interface setup and communications because the signals are
the same for each 16-bit sequence, except during the first cycle.
The sequence of registers (and checksum value) in the burst read
response depends on which sample clock mode that the ADIS16475
is operating in (Register MSC_CTRL, Bits[4:2], see Table 105). In
all clock modes, except when operating in scaled sync mode
(Register MSC_CTRL, Bits[4:2] = 010), the burst read response
includes the following registers and value: DIAG_STAT,
X_GYRO_OUT, Y_GYRO_OUT, Z_GYRO_OUT, X_ACCL_
OUT, Y_ACCL_OUT, Z_ACCL_OUT, TEMP_OUT, DATA_
CNTR, and the checksum value. In these cases, use the following
formula to verify the checksum value, treating each byte in the
formula as an independent, unsigned, 8-bit number:
Checksum = DIAG_STAT, Bits[15:8] + DIAG_STAT, Bits[7:0] +
X_GYRO_OUT, Bits[15:8] + X_GYRO_OUT, Bits[7:0] +
Y_GYRO_OUT, Bits[15:8] + Y_GYRO_OUT, Bits[7:0] +
Z_GYRO_OUT, Bits[15:8] + Z_GYRO_OUT, Bits[7:0] +
X_ACCL_OUT, Bits[15:8] + X_ACCL_OUT, Bits[7:0] +
Y_ACCL_OUT, Bits[15:8] + Y_ACCL_OUT, Bits[7:0] +
Z_ACCL_OUT, Bits[15:8] + Z_ACCL_OUT, Bits[7:0] +
TEMP_OUT, Bits[15:8] + TEMP_OUT, Bits[7:0] +
DATA_CNTR, Bits[15:8] + DATA_CNTR, Bits[7:0]
Rev. D | Page 15 of 37
ADIS16475
Data Sheet
When operating in scaled sync mode (Register MSC_CTRL,
Bits[4:2] = 010), the burst read response includes the following
registers and value: DIAG_STAT, X_GYRO_OUT,
Y_GYRO_OUT, Z_GYRO_OUT, X_ACCL_OUT,
Y_ACCL_OUT, Z_ACCL_OUT, TEMP_OUT, TIME_STAMP,
and the checksum value. In this case, use the following formula
to verify the checksum value, treating each byte in the formula
as an independent, unsigned, 8-bit number.
Checksum = DIAG_STAT, Bits[15:8] + DIAG_STAT, Bits[7:0] +
X_GYRO_OUT, Bits[15:8] + X_GYRO_OUT, Bits[7:0] +
Y_GYRO_OUT, Bits[15:8] + Y_GYRO_OUT, Bits[7:0] +
Z_GYRO_OUT, Bits[15:8] + Z_GYRO_OUT, Bits[7:0] +
X_ACCL_OUT, Bits[15:8] + X_ACCL_OUT, Bits[7:0] +
Y_ACCL_OUT, Bits[15:8] + Y_ACCL_OUT, Bits[7:0] +
Z_ACCL_OUT, Bits[15:8] + Z_ACCL_OUT, Bits[7:0] +
TEMP_OUT, Bits[15:8] + TEMP_OUT, Bits[7:0] +
TIME_STAMP, Bits[15:8] + TIME_STAMP, Bits[7:0]
Memory Structure
Figure 35 provides a functional diagram for the memory
structure of the ADIS16475. The flash memory bank contains
the operational code, unit specific calibration coefficients, and
user configuration settings. During initialization (power
application or reset recover), this information loads from the
flash memory into the static random access memory (SRAM),
which supports all normal operation, including register access
through the SPI port. Writing to a configuration register using
the SPI updates the SRAM location of the register, but does not
automatically update its settings in the flash memory bank. The
manual flash memory update command (Register GLOB_CMD,
Bit 3, see Table 113) provides a convenient method for saving
all of these settings to the flash memory bank at one time. A yes
in the flash backup column of Table 8 identifies the registers
that have storage support in the flash memory bank.
MANUAL
FLASH
BACKUP
Each configuration register contains 16 bits (two bytes). Bits[7:0]
contain the low byte, and Bits[15:8] contain the high byte of
each register. Each byte has its own unique address in the user
register map (see Table 8). Updating the contents of a register
requires writing to both of its bytes in the following sequence:
low byte first, high byte second. There are three parts to coding
a SPI command (see Figure 30) that write a new byte of data to
a register: the write bit (R/W = 1), the address of the byte, [A6:A0],
and the new data for that location, [DC7:DC0]. Figure 34 shows a
coding example for writing 0x0004 to the FILT_CTRL register
(see Table 101). In Figure 34, the 0xDC04 command writes 0x04 to
Address 0x5C (lower byte) and the 0xDD00 command writes
0x00 to Address 0x5D (upper byte).
CS
DIN
0xDC04
0xDD00
15436-030
SCLK
Figure 34. SPI Sequence for Writing 0x0004 to FILT_CTRL
Rev. D | Page 16 of 37
NONVOLATILE
FLASH MEMORY
VOLATILE
SRAM
SPI ACCESS
(NO SPI ACCESS)
START-UP
RESET
Figure 35. SRAM and Flash Memory Diagram
15436-031
DEVICE CONFIGURATION
Data Sheet
ADIS16475
USER REGISTER MEMORY MAP
Table 8. User Register Memory Map (N/A Means Not Applicable)
Name
Reserved
DIAG_STAT
X_GYRO_LOW
X_GYRO_OUT
Y_GYRO_LOW
Y_GYRO_OUT
Z_GYRO_LOW
Z_GYRO_OUT
X_ACCL_LOW
X_ACCL_OUT
Y_ACCL_LOW
Y_ACCL_OUT
Z_ACCL_LOW
Z_ACCL_OUT
TEMP_OUT
TIME_STAMP
Reserved
DATA_CNTR
X_DELTANG_LOW
X_DELTANG_OUT
Y_DELTANG_LOW
Y_DELTANG_OUT
Z_DELTANG_LOW
Z_DELTANG_OUT
X_DELTVEL_LOW
X_DELTVEL_OUT
Y_DELTVEL_LOW
Y_DELTVEL_OUT
Z_DELTVEL_LOW
Z_DELTVEL_OUT
Reserved
XG_BIAS_LOW
XG_BIAS_HIGH
YG_BIAS_LOW
YG_BIAS_HIGH
ZG_BIAS_LOW
ZG_BIAS_HIGH
XA_BIAS_LOW
XA_BIAS_HIGH
YA_BIAS_LOW
YA_BIAS_HIGH
ZA_BIAS_LOW
ZA_BIAS_HIGH
Reserved
FILT_CTRL
RANG_MDL
MSC_CTRL
UP_SCALE
R/W
N/A
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
N/A
R
R
R
R
R
R
R
R
R
R
R
R
R
N/A
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
N/A
R/W
R
R/W
R/W
Flash Backup
N/A
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
N/A
No
No
No
No
No
No
No
No
No
No
No
No
No
N/A
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
N/A
Yes
No
Yes
Yes
Address
0x00, 0x01
0x02, 0x03
0x04, 0x05
0x06, 0x07
0x08, 0x09
0x0A, 0x0B
0x0C, 0x0D
0x0E, 0x0F
0x10, 0x11
0x12, 0x13
0x14, 0x15
0x16, 0x17
0x18, 0x19
0x1A, 0x1B
0x1C, 0x1D
0x1E, 0x1F
0x20, 0x21
0x22, 0x23
0x24, 0x25
0x26, 0x27
0x28, 0x29
0x2A, 0x2B
0x2C, 0x2D
0x2E, 0x2F
0x30, 0x31
0x32, 0x33
0x34, 0x35
0x36, 0x37
0x38, 0x39
0x3A, 0x3B
0x3C to 0x3F
0x40, 0x41
0x42, 0x43
0x44, 0x45
0x46, 0x47
0x48, 0x49
0x4A, 0x4B
0x4C, 0x4D
0x4E, 0x4F
0x50, 0x51
0x52, 0x53
0x54, 0x55
0x56, 0x57
0x58 to 0x5B
0x5C, 0x5D
0x5E, 0x5F
0x60, 0x61
0x62, 0x63
Default
N/A
0x0000
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
0x0000
0x0000
0x0000
0x0000
0x0000
0x0000
0x0000
0x0000
0x0000
0x0000
0x0000
0x0000
N/A
0x0000
N/A 1
0x00C1
0x07D0
DEC_RATE
R/W
Yes
0x64, 0x65
0x0000
Rev. D | Page 17 of 37
Register Description
Reserved
Output, system error flags
Output, x-axis gyroscope, low word
Output, x-axis gyroscope, high word
Output, y-axis gyroscope, low word
Output, y-axis gyroscope, high word
Output, z-axis gyroscope, low word
Output, z-axis gyroscope, high word
Output, x-axis accelerometer, low word
Output, x-axis accelerometer, high word
Output, y-axis accelerometer, low word
Output, y-axis accelerometer, high word
Output, z-axis accelerometer, low word
Output, z-axis accelerometer, high word
Output, temperature
Output, time stamp
Reserved
New data counter
Output, x-axis delta angle, low word
Output, x-axis delta angle, high word
Output, y-axis delta angle, low word
Output, y-axis delta angle, high word
Output, z-axis delta angle, low word
Output, z-axis delta angle, high word
Output, x-axis delta velocity, low word
Output, x-axis delta velocity, high word
Output, y-axis delta velocity, low word
Output, y-axis delta velocity, high word
Output, z-axis delta velocity, low word
Output, z-axis delta velocity, high word
Reserved
Calibration, offset, gyroscope, x-axis, low word
Calibration, offset, gyroscope, x-axis, high word
Calibration, offset, gyroscope, y-axis, low word
Calibration, offset, gyroscope, y-axis, high word
Calibration, offset, gyroscope, z-axis, low word
Calibration, offset, gyroscope, z-axis, high word
Calibration, offset, accelerometer, x-axis, low word
Calibration, offset, accelerometer, x-axis, high word
Calibration, offset, accelerometer, y-axis, low word
Calibration, offset, accelerometer, y-axis, high word
Calibration, offset, accelerometer, z-axis, low word
Calibration, offset, accelerometer, z-axis, high word
Reserved
Control, Bartlett window FIR filter
Measurement range (model specific) identifier
Control, input/output and other miscellaneous options
Control, scale factor for input clock, pulse per second (PPS)
mode
Control, decimation filter (output data rate)
ADIS16475
Name
NULL_CNFG
GLOB_CMD
Reserved
FIRM_REV
FIRM_DM
FIRM_Y
PROD_ID
SERIAL_NUM
USER_SCR_1
USER_SCR_2
USER_SCR_3
FLSHCNT_LOW
FLSHCNT_HIGH
1
Data Sheet
R/W
R/W
W
N/A
R
R
R
R
R
R/W
R/W
R/W
R
R
Flash Backup
Yes
No
N/A
No
No
No
No
No
Yes
Yes
Yes
No
No
Address
0x66, 0x67
0x68, 0x69
0x6A to 0x6B
0x6C, 0x6D
0x6E, 0x6F
0x70, 0x71
0x72, 0x73
0x74, 0x75
0x76, 0x77
0x78, 0x79
0x7A, 0x7B
0x7C, 0x7D
0x7E, 0x7E
Default
0x070A
N/A
N/A
N/A
N/A
N/A
0x405B
N/A
N/A
N/A
N/A
N/A
N/A
See Table 102 for the default value in this register, which is model specific.
Rev. D | Page 18 of 37
Register Description
Control, bias estimation period
Control, global commands
Reserved
Identification, firmware revision
Identification, date code, day and month
Identification, date code, year
Identification, device number
Identification, serial number
User Scratch Register 1
User Scratch Register 2
User Scratch Register 3
Output, flash memory write cycle counter, lower word
Output, flash memory write cycle counter, upper word
Data Sheet
ADIS16475
USER REGISTER DEFINTIONS
Status/Error Flag Indicators (DIAG_STAT)
GYROSCOPE DATA
Table 9. DIAG_STAT Register Definition
The gyroscopes in the ADIS16475 measure the angular rate of
rotation around three orthogonal axes (x, y, and z). Figure 36
shows the orientation of each gyroscope axis, along with the
direction of rotation that produces a positive response in each
of their measurements.
Access
R
Flash Backup
No
Table 10. DIAG_STAT Bit Assignments
Bits
[15:8]
7
6
5
4
3
2
1
0
Description
Reserved.
Clock error. A 1 indicates that the internal data sampling
clock (fSM, see Figure 19 and Figure 20) does not
synchronize with the external clock, which only applies
when using scaled sync mode (Register MSC_CTRL,
Bits[4:2] = 010, see Table 105). When this error occurs,
adjust the frequency of the clock signal on the SYNC pin
to operate within the appropriate range.
Memory failure. A 1 indicates a failure in the flash memory
test (Register GLOB_CMD, Bit 4, see Table 113), which
involves a comparison between a cyclic redundancy
check (CRC) calculation of the present flash memory and
a CRC calculation from the same memory locations at
the time of initial programming (during the production
process). If this error occurs, repeat the same test. If this
error persists, replace the ADIS16475 device.
Sensor failure. A 1 indicates failure of at least one sensor,
at the conclusion of the self test (Register GLOB_CMD,
Bit 2, see Table 113). If this error occurs, repeat the same
test. If this error persists, replace the ADIS16475. Motion
during the execution of this test can cause a false failure.
Standby mode. A 1 indicates that the voltage across
VDD and GND is
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