Tactical Grade,
Ten Degrees of Freedom Inertial Sensor
Data Sheet
ADIS16488A
FEATURES
Triaxial, digital gyroscope, ±450°/sec dynamic range
±0.05° orthogonal alignment error
5.1°/hr in-run bias stability
0.26°/√hr angular random walk
0.01% nonlinearity
Triaxial, digital accelerometer, ±18 g
Triaxial, delta angle and delta velocity outputs
Triaxial, digital magnetometer, ±2.5 gauss
Digital pressure sensor, 300 mbar to 1100 mbar
Fast start-up time, ~500 ms
Factory-calibrated sensitivity, bias, and axial alignment
Calibration temperature range: −40°C to +85°C
SPI-compatible serial interface
Embedded temperature sensor
Programmable operation and control
Automatic and manual bias correction controls
4 FIR filter banks, 120 configurable taps
Digital input/output: data-ready alarm indicator,
external clock
Alarms for condition monitoring
Power-down/sleep mode for power management
Optional external sample clock input: up to 2.4 kHz
Single command self test
Single-supply operation: 3.0 V to 3.6 V
2000 g shock survivability
Operating temperature range: −55°C to +105°C (CML)
APPLICATIONS
Platform stabilization and control
Navigation
Personnel tracking
Instrumentation
Robotics
GENERAL DESCRIPTION
The ADIS16488A iSensor® device is a complete inertial system
that includes a triaxis gyroscope, a triaxis accelerometer, triaxis
magnetometer, and pressure sensor. Each inertial sensor in the
ADIS16488A combines industry-leading iMEMS® technology
with signal conditioning that optimizes dynamic performance.
The factory calibration characterizes each sensor for sensitivity,
bias, alignment, and linear acceleration (gyroscope bias). As a
result, each sensor has its own dynamic compensation formulas that
provide accurate sensor measurements.
The ADIS16488A 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 SPI and register structure provide a simple interface for
data collection and configuration control.
The ADIS16488A uses the same footprint and connector system as
the ADIS16375, ADIS16480, and ADIS16485, which greatly
simplifies the upgrade process. The ADIS16488A is packaged in
a module that is approximately 47 mm × 44 mm × 14 mm and
includes a standard connector interface.
FUNCTIONAL BLOCK DIAGRAM
CONTROLLER
CLOCK
TRIAXIAL
GYRO
TRIAXIAL
ACCEL
POWER
MANAGEMENT
CS
SCLK
DIN
DOUT
GND
VDD
TEMP
VDD
DIO1 DIO2 DIO3 DIO4
VDDRTC
RST
SPI
TRIAXIAL
MAGN
PRESSURE
SELF T EST I/O ALARMS
OUTPUT
DATA
REGISTERS
USER
CONTROL
REGISTERS
CALIBRATION
AND
FILTERS
ADIS16488A
11855-001
Figure 1.
Rev. C Document Feedback
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700 ©2014–2015 Analog Devices, Inc. All rights reserved.
Technical Support www.analog.com
ADIS16488A Data Sheet
Rev. C | Page 2 of 35
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
General Description ......................................................................... 1
Functional Block Diagram .............................................................. 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 3
Timing Specifications .................................................................. 5
Absolute Maximum Ratings ............................................................ 7
Thermal Resistance ...................................................................... 7
ESD Caution .................................................................................. 7
Pin Configuration and Function Descriptions ............................. 8
Typical Performance Characteristics ............................................. 9
Theory of Operation ...................................................................... 10
Register Structure ....................................................................... 10
SPI Communication ................................................................... 10
Device Configuration ................................................................ 11
Reading Sensor Data .................................................................. 11
User Registers .................................................................................. 12
Output Data Registers .................................................................... 15
Inertial Sensor Data Format ...................................................... 15
Rotation Rate (Gyroscope) ........................................................ 15
Acceleration ................................................................................. 16
Delta Angles ................................................................................ 16
Delta Velocity .............................................................................. 17
Magnetometers ........................................................................... 17
Barometer .................................................................................... 18
Internal Temperature ................................................................. 18
Status/Alarm Indicators ............................................................. 18
Firmware Revision ..................................................................... 19
Product Identification ................................................................ 20
Digital Signal Processing ............................................................... 21
Gyroscopes/Accelerometers ..................................................... 21
Averaging/Decimation Filter .................................................... 21
Magnetometer/Barometer ......................................................... 21
FIR Filter Banks .......................................................................... 22
Calibration ....................................................................................... 24
Gyroscopes .................................................................................. 24
Accelerometers ........................................................................... 25
Magnetometers ........................................................................... 25
Barometers .................................................................................. 27
Restoring Factory Calibration .................................................. 27
Point of Percussion Alignment ................................................. 27
Alarms .............................................................................................. 28
Static Alarm Use ......................................................................... 28
Dynamic Alarm Use .................................................................. 29
System Controls .............................................................................. 30
Global Commands ..................................................................... 30
Memory Management ............................................................... 30
General-Purpose Input/Output................................................ 31
Power Management ................................................................... 31
Applications Information .............................................................. 33
Mounting Best Practices ............................................................ 33
Evaluation Tools ......................................................................... 34
Power Supply Considerations ................................................... 34
Outline Dimensions ....................................................................... 35
Ordering Guide .......................................................................... 35
REVISION HISTORY
8/15—Rev. B to Rev. C
Changes to Table 72, Table 73, and Table 74 ............................... 24
Changes to Table 82, Table 83, and Table 84 ............................... 25
2/15—Rev. A to Rev. B
Change to Features Section ............................................................. 1
Changes to t2 Parameter, Table 2, and Figure 2 ............................ 5
Added Table 3; Renumbered Sequentially .................................... 5
Changes to Figure 4 .......................................................................... 6
Change to Dual Memory Structure Section ................................ 11
Change to Table 72, Table 73, and Table 74 ................................ 24
Change to Table 82, Table 83, and Table 84 ................................ 25
5/14—Rev. 0 to Rev. A
Changes to Table 71, Table 72, and Table 73 ............................... 23
Changes to Table 81, Table 82, and Table 83 ............................... 24
1/14—Revision 0: Initial Version
Data Sheet ADIS16488A
SPECIFICATIONS
TC = 25°C, VDD = 3.3 V, angular rate = 0°/sec, dynamic range = ±450°/sec ± 1 g, 300 mbar to 1100 mbar, unless otherwise noted.
Table 1.
Parameter Test Conditions/Comments Min Typ Max Unit
GYROSCOPES
Dynamic Range
±450
±480
Sensitivity
x_GYRO_OUT and x_GYRO_LOW (32-bit)
3.052 × 10
−7
Repeatability1 −40°C ≤ TC ≤ +85°C ±1 %
Sensitivity Temperature Coefficient −40°C ≤ TC ≤ +85°C, 1 σ ±35 ppm/°C
Misalignment Axis to axis ±0.05 Degrees
Axis to frame (package) ±1.0 Degrees
Nonlinearity Best fit straight line, FS = 450°/sec 0.01 % of FS
Bias Repeatability1, 2 −40°C ≤ TC ≤ +85°C, 1 σ ±0.2 °/sec
In-Run Bias Stability
1 σ
5.1
Angular Random Walk 1 σ 0.26 °/√hr
Bias Temperature Coefficient −40°C ≤ TC ≤ +85°C, 1 σ ±0.0025 °/sec/°C
Linear Acceleration Effect on Bias Any axis, 1 σ (CONFIG[7] = 1) 0.009 °/sec/g
Output Noise No filtering 0.135 °/sec rms
Rate Noise Density f = 10 Hz to 40 Hz, no filtering 0.0059 °/sec/√Hz rms
3 dB Bandwidth 330 Hz
Sensor Resonant Frequency
18
ACCELEROMETERS Each axis
Dynamic Range ±18 g
Sensitivity x_ACCL_OUT and x_ACCL_LOW (32-bit) 1.221 × 10−8 g/LSB
Repeatability1 −40°C ≤ TC ≤ +85°C ±0.5 %
Sensitivity Temperature Coefficient −40°C ≤ TC ≤ +85°C, 1 σ ±25 ppm/°C
Misalignment Axis to axis ±0.035 Degrees
Axis to frame (package)
±1.0
Nonlinearity Best fit straight line, ±10 g 0.1 % of FS
Best fit straight line, ±18 g 0.5 % of FS
Bias Repeatability1, 2 −40°C ≤ TC ≤ +85°C, 1 σ ±16 mg
In-Run Bias Stability 1 σ 0.07 mg
Velocity Random Walk 1 σ 0.029 m/sec/√hr
Bias Temperature Coefficient −40°C ≤ TC ≤ +85°C ±0.1 mg/°C
Output Noise
No filtering
1.29
Noise Density f = 10 Hz to 40 Hz, no filtering 0.063 mg/√Hz rms
3 dB Bandwidth 330 Hz
Sensor Resonant Frequency 5.5 kHz
MAGNETOMETER
Dynamic Range ±2.5 gauss
Sensitivity
0.1
Initial Sensitivity Tolerance
±2
Sensitivity Temperature Coefficient ADIS16488BMLZ, −40°C ≤ TC ≤ +85°C, 1 σ 275 ppm/°C
ADIS16488CMLZ, −40°C ≤ TC ≤ +85°C, 1 σ 60 ppm/°C
Misalignment Axis to axis 0.35 Degrees
Axis to frame (package) 1.0 Degrees
Nonlinearity
Best fit straight line
0.5
Initial Bias Error 0 gauss stimulus ±15 mgauss
Bias Temperature Coefficient ADIS16488BMLZ, −40°C ≤ TC ≤ +85°C, 1 σ 0.3 mgauss/°C
ADIS16488CMLZ, −40°C ≤ TC ≤ +85°C, 1 σ 0.03 mgauss/°C
Output Noise No filtering 0.22 mgauss rms
Noise Density f = 2 Hz to 5 Hz, no filtering 0.042 mgauss/√Hz
3 dB Bandwidth
330
Rev. C | Page 3 of 35
ADIS16488A Data Sheet
Parameter Test Conditions/Comments Min Typ Max Unit
BAROMETER
Pressure Range 300 1100 mbar
Extended 10 1200 mbar
Sensitivity BAROM_OUT and BAROM_LOW (32-bit) 6.1 × 10−7 mbar/LSB
Error with Supply 0.04 %/V
Total Error
4.5
Relative Error3 −40°C ≤ TC ≤ +85°C 2.5 mbar
Nonlinearity4 Best fit straight line, FS = 1100 mbar 0.1 % of FS
−40°C ≤ TC ≤ +85°C 0.2 % of FS
Linear-g Sensitivity ±1 g, 1 σ 0.005 mbar/g
Noise 0.025 mbar rms
TEMPERATURE SENSOR
Scale Factor
Output = 0x0000 at 25°C (±5°C)
0.00565
LOGIC INPUTS5
Input High Voltage, VIH 2.0 V
Input Low Voltage, VIL 0.8 V
CS Wake-Up Pulse Width 20 µs
Logic 1 Input Current, IIH VIH = 3.3 V 10 µA
Logic 0 Input Current, I
IL
V
IL
= 0 V
All Pins Except RST 10 µA
RST Pin 0.33 mA
Input Capacitance, CIN 10 pF
DIGITAL OUTPUTS
Output High Voltage, VOH ISOURCE = 0.5 mA 2.4 V
Output Low Voltage, V
OL
I
SINK
= 2.0 mA
0.4
FLASH MEMORY Endurance6 100,000 Cycles
Data Retention7 TJ = 85°C 20 Years
FUNCTIONAL TIMES8 Time until data is available
Power-On Start-Up Time 500 ms
Reset Recovery Time9 500 ms
Sleep Mode Recovery Time
500
Flash Memory
Update Time 375 ms
Test Time 50 ms
Automatic Self Test Time Using internal clock, 100 SPS 12 ms
CONVERSION RATE 2.46 kSPS
Initial Clock Accuracy
0.02
Temperature Coefficient 40 ppm/°C
Sync Input Clock 0.710 2.4 kHz
POWER SUPPLY, VDD Operating voltage range 3.0 3.6 V
Power Supply Current11 Normal mode, VDD = 3.3 V, µ ± σ 245 mA
Sleep mode, VDD = 3.3 V
12.2
Power-down mode, VDD = 3.3 V 45 µA
POWER SUPPLY, VDDRTC Operating voltage range 3.0 3.6 V
Real-Time Clock Supply Current Normal mode, VDDRTC = 3.3 V 13 µA
1 The repeatability specifications represent analytical projections based on the following drift contributions and conditions: temperature hysteresis (−40°C to +85°C),
electronics drift (high temperature operating life test: +110°C, 500 hours), drift from temperature cycling (JESD22, Method A104-C, Method N, 500 cycles, −55°C to +85°C), rate
random walk (10-year projection), and broadband noise.
2 Bias repeatability describes a long-term behavior over a variety of conditions. Short-term repeatability relates to the in-run bias stability and noise density specifications.
3 The relative error assumes that the initial error, at 25°C, is corrected in the end application.
4 Specification assumes a full scale (FS) of 1000 mbar.
5 The digital input/output signals use a 3.3 V system.
6 Endurance is qualified as per JEDEC Standard 22, Method A117, measured at −40°C, +25°C, +85°C, and +125°C.
7 The data retention specification assumes a junction temperature (TJ) of 85°C per JEDEC Standard 22, Method A117. Data retention lifetime decreases with TJ.
8 These times do not include thermal settling and internal filter response times, which may affect overall accuracy.
9 The RST line must be in a low state for at least 10 μs to assure a proper reset initiation and recovery.
10 Device functions at clock rates below 0.7 kHz, but at reduced performance levels.
11 Supply current transients can reach 600 mA during initial start up or reset recovery.
Rev. C | Page 4 of 35
Data Sheet ADIS16488A
TIMING SPECIFICATIONS
TC = 25°C, VDD = 3.3 V, unless otherwise noted.
Table 2.
Normal Mode
Parameter Description Min1 Typ Max1 Unit
fSCLK Serial clock 0.01 15 MHz
tSTALL 2 Stall period between data 2 µs
tCLS Serial clock low period 31 ns
t
CHS
Serial clock high period
31
ns
tCS Chip select to clock edge 32 ns
tDAV DOUT valid after SCLK edge 10 ns
t
DSU
DIN setup time before SCLK rising edge
2
ns
tDHD DIN hold time after SCLK rising edge 2 ns
tDR, tDF DOUT rise/fall times, ≤100 pF loading 3 8 ns
tDSOE CS assertion to data out active 0 11 ns
tHD SCLK edge to data out invalid 0 ns
tSFS Last SCLK edge to CS deassertion 32 ns
tDSHI CS deassertion to data out high impedance 0 9 ns
t1 Input sync pulse width 5 µs
t2 Input sync to data invalid 490 µs
t3 Input sync period 417 µs
1 Guaranteed by design and characterization, but not tested in production.
2 See Table 3 for exceptions to the stall time rating
Table 3. Register Specific Stall Times
Register Function Minimum Stall Time (μs)
FNCTIO_CTRL Configure DIOx functions 15
FLTR_BNK0 Enable/select FIR filter banks 10
FLTR_BNK1 Enable/select FIR filter banks 10
NULL_CFG Configure autonull bias function 10
GLOB_CMD[1] Self-test 12,000
GLOB_CMD[2] Flash memory test 50,000
GLOB_CMD[3] Flash memory update 375,000
GLOB_CMD[6] Factory calibration restore 75,000
GLOB_CMD[7] Software reset 120,000
Rev. C | Page 5 of 35
ADIS16488A Data Sheet
Timing Diagrams
CS
SCLK
DOUT
DIN
1 2 3 4 5 6 15 16
R/W A5A6 A4 A3 A2 D2
MSB DB14
D1 LSB
DB13 DB12 DB10DB11 DB2 LSBDB1
tCS
tDSHI
tDR
tSFS
tDF
tDAV tHD
tCHS tCLS
tDSOE
tDHD
tDSU
11855-002
Figure 2. SPI Timing and Sequence
CS
SCLK
t
STALL
11855-003
Figure 3. Stall Time and Data Rate
t
3
t
2
t
1
SYNC
CLO CK (CLKIN)
DATA
READY
OUTPUT
REGISTERS DAT A VALI D DATA VALID
11855-004
Figure 4. Input Clock Timing Diagram
Rev. C | Page 6 of 35
Data Sheet ADIS16488A
ABSOLUTE MAXIMUM RATINGS
Table 4.
Parameter Rating
Acceleration
Any Axis, Unpowered
2000 g
Any Axis, Powered 2000 g
VDD to GND −0.3 V to +3.6 V
Digital Input Voltage to GND −0.3 V to VDD + 0.2 V
Digital Output Voltage to GND −0.3 V to VDD + 0.2 V
Operating Temperature Range
ADIS16488BMLZ
−40°C to +105°C
ADIS16488CMLZ −55°C to +105°C
Storage Temperature Range1 −65°C to +150°C
Barometric Pressure 2 bar
1 Extended exposure to temperatures that are lower than −55°C or higher
than +105°C can 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.
THERMAL RESISTANCE
Table 5. Package Characteristics
Package Type θJA θJC
Device
Weight
24-Lead Module (ML-24-6) 22.8°C/W 10.1°C/W 48 g
ESD CAUTION
Rev. C | Page 7 of 35
ADIS16488A Data Sheet
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
1
DIO3
SCLK
DIN
DIO1
DIO2
VDD
GND
GND
DNC
DNC
DNC
VDDRTC
DIO4
DOUT
CS
RST
VDD
VDD
GND
DNC
DNC
DNC
DNC
DNC
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
ADIS16488A
TOP VIEW
(No t t o Scal e)
NOTES
1. THIS REPRESENTATION DISPLAYS THE TOP VI EW PI NOUT
FO R THE M ATI NG SO CKE T CO NNE CTOR.
2. T HE ACTUAL CONNECTOR P INS ARE NOT V ISIBLE FRO M
THE TOP VI EW .
3. M ATING CO NNE CTOR: S AM TEC CLM-112- 02 OR EQUI VALENT.
4. DNC = DO NO T CO NNE CT TO T HE S E P INS.
11855-005
Figure 5. Mating Connector Pin Assignments
PIN 1
PIN 23
PIN 1 PIN 2
11855-006
Figure 6. Axial Orientation (Top Side Facing Up)
Table 6. Pin Function Descriptions
Pin No. Mnemonic Type Description
1
DIO3
Input/output
Configurable Digital Input/Output.
2 DIO4 Input/output Configurable Digital Input/Output.
3 SCLK Input SPI Serial Clock.
4 DOUT Output SPI Data Output. Clocks output on SCLK falling edge.
5 DIN Input SPI Data Input. Clocks input on SCLK rising edge.
6
CS
Input
SPI Chip Select.
7 DIO1 Input/output Configurable Digital Input/Output.
8 RST Input Reset.
9 DIO2 Input/output Configurable Digital Input/Output.
10, 11, 12 VDD Supply Power Supply.
13, 14, 15 GND Supply Power Ground.
16 to 22, 24
DNC
Not applicable
Do Not Connect. Do not connect to these pins.
23 VDDRTC Supply Real-Time Clock Power Supply.
Rev. C | Page 8 of 35
Data Sheet ADIS16488A
TYPICAL PERFORMANCE CHARACTERISTICS
100
1
10
0.01 0.1 110 100 1000 10000
ROOT ALLAN VARIANCE ( °/Hou r)
INTEGRATION PERIOD (Seconds)
+1σ
–1σ
AVERAGE
11855-007
Figure 7. Gyroscope Allan Variance, 25°C
0.001
0.00001
0.0001
0.01 0.1 110 100 1000 10000
ROOT ALLAN VARIANCE (g)
INTEGRATION PERIOD (Seconds)
+1σ
–1σ
AVERAGE
11855-008
Figure 8. Accelerometer Allan Variance, 25°C
0.3
–0.3
–0.2
–0.1
0
0.1
0.2
–50 –40 –30 –20 –10 010 20 30 40 50 60 70 80
90 100 110
BIAS E RROR (°/ sec)
TEMPERATURE (°C)
11855-209
+3σ
–3σ
AVERAGE
Figure 9. Gyroscope Bias Error vs. Temperature
0.8
–0.8
–0.6
–0.4
–0.2
0
0.2
0.4
0.6
–50 –40 –30 –20 –10 010 20 30 40 50 60 70 80 90 100 110
SENSITIVIT Y ERROR (% FS)
TEMPERATURE (°C)
11855-210
+3σ
–3σ
AVERAGE
Figure 10. Gyroscope Scale (Sensitivity) Error vs. Temperature
Rev. C | Page 9 of 35
ADIS16488A Data Sheet
Rev. C | Page 10 of 35
THEORY OF OPERATION
The ADIS16488A is an autonomous sensor system that self
starts when it has a valid power supply. After running through its
initialization process, it begins sampling, processing, and
loading calibrated sensor data into the output registers, which
are accessible using the SPI port. The SPI port typically connects to
a compatible port on an embedded processor, using the connec-
tions as shown in Figure 11.
The four SPI signals facilitate synchronous, serial data communi-
cation. Connect the reset line (RST) to VDD or do not connect
it to anything for normal operation. The factory default
configuration provides users with a data ready signal on the
DIO2 pin, which pulses high when new data is available in the
output data registers.
SYSTEM
PROCESSOR
SPI MASTER
SCLK
CS
DIN
DOUT
SCLK
SS
MOSI
MISO
+3.3V
IRQ DIO2
VDD
I/O LINES ARE COMPATIBLE WITH
3.3V LOGIC LEVELS
10
6
3
5
4
9
11 12 23
13 14 15
ADIS16488A
11855-009
Figure 11. Electrical Connection Diagram
Table 7. Generic Master Processor Pin Names and Functions
Mnemonic Function
SS Slave select
IRQ Interrupt request
MOSI Master output, slave input
MISO Master input, slave output
SCLK Serial clock
Embedded processors typically use control registers to configure
their serial ports for communicating with SPI slave devices,
such as the ADIS16488A. Table 8 provides a list of settings
describing the SPI protocol of the ADIS16488A. The initializa-
tion routine of the master processor typically establishes these
settings using firmware commands to write them into its serial
control registers.
Table 8. Generic Master Processor SPI Settings
Processor Setting Description
Master The ADIS16488A operates as a slave
SCLK ≤ 15 MHz Maximum serial clock rate
SPI Mode 3 CPOL = 1 (polarity), and CPHA = 1 (phase)
MSB-First Mode Bit sequence
16-Bit Mode Shift register/data length
REGISTER STRUCTURE
The register structure and SPI port provide a bridge between
the sensor processing system and an external, master processor.
It contains both output data and control registers. The output
data registers include the latest sensor data, a real-time clock, error
flags, alarm flags, and identification data. The control registers
include sample rate, filtering, input/output, alarms, calibration,
and diagnostic configuration options. All communication
between the ADIS16488A and an external processor involves
either reading or writing to one of the user registers.
DSP OUTPUT
REGISTERS
CONTROL
REGISTERS
TRIAXIS
GYRO
TRIAXIS
MAGN
BARO
TEMP
SENSOR
CONTROLLER
TRIAXIS
ACCEL
SPI
11855-010
Figure 12. Basic Operation
The register structure uses a paged addressing scheme that is
composed of 13 pages, with each page containing 64 register
locations. Each register is 16 bits wide, with each byte having its
own unique address within the memory map of that page. The
SPI port has access to one page at a time, using the bit sequence
shown in Figure 13.
Select the page to activate for SPI access by writing its code to
the PAGE_ID register. Read the PAGE_ID register to determine
which page is currently active. Table 9 displays the PAGE_ID
contents for each page, together with their basic functions. The
PAGE_ID register is located at Address 0x00 on every page.
Table 9. User Register Page Assignments
Page PAGE_ID Function
0 0x00 Output data, clock, identification
1 0x01 Reserved
2 0x02 Calibration
3 0x03 Control: sample rate, filtering, input/output,
alarms
4 0x04 Serial number
5 0x05 FIR Filter Bank A, Coefficient 0 to Coefficient 59
6 0x06 FIR Filter Bank A, Coefficient 60 to Coefficient 119
7 0x07 FIR Filter Bank B, Coefficient 0 to Coefficient 59
8 0x08 FIR Filter Bank B, Coefficient 60 to Coefficient 119
9 0x09 FIR Filter Bank C, Coefficient 0 to Coefficient 59
10 0x0A FIR Filter Bank C, Coefficient 60 to Coefficient 119
11 0x0B FIR Filter Bank D, Coefficient 0 to Coefficient 59
12 0x0C FIR Filter Bank D, Coefficient 60 to Coefficient 119
SPI COMMUNICATION
If the previous command was a read request, the SPI port supports
full duplex communication, which enables external processors to
write to DIN while reading DOUT (see Figure 13). Figure 13
provides a guideline for the bit coding on both DIN and DOUT.
Data Sheet ADIS16488A
Rev. C | Page 11 of 35
R/W R/W
A6 A5 A4 A3 A2 A1 A0 DC7 DC6 DC5 DC4 DC3 DC2 DC1 DC0
D0D1D2D3D4D5D6D7D8D9D10D11D12D13D14D15
CS
SCLK
DIN
DOUT
A6 A5
D13D14D15
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.
11855-015
Figure 13. SPI Communication Bit Sequence
DEVICE CONFIGURATION
The SPI provides write access to the control registers, one byte at
a time, using the bit assignments shown in Figure 13. Each register
has 16 bits, where Bits[7:0] represent the lower address (listed in
Table 10) and Bits[15:8] represent the upper address. Write to
the lower byte of a register first, followed by a write to its upper
byte (the only register that changes with a single write to its
lower byte is the PAGE_ID register).
For a write command, the first bit in the DIN sequence is set to 1.
Address Bits[A6:A0] represent the target address, and Data
Command Bits[DC7:DC0] represent the data being written to the
location. Figure 14 provides an example of writing 0x03 to
Address 0x00 (PAGE_ID [7:0]) using DIN = 0x8003. This write
command activates the control page for SPI access.
SCLK
CS
DIN
DIN = 1000 0000 0000 0011 = 0x8003, WRITES 0x03 TO ADDRESS 0x00
11855-011
Figure 14. SPI Sequence for Activating the Control Page (DIN = 0x8003)
Dual Memory Structure
Writing configuration data to a control register updates its SRAM
contents, which are volatile. After optimizing each relevant control
register setting in a system, use the manual flash update command,
which is located in GLOB_CMD[3] on Page 3 of the register map.
Activate the manual flash update command by turning to Page 3
(DIN = 0x8003) and setting GLOB_CMD[3] = 1 (DIN = 0x8208,
then DIN = 0x8300). For a flash memory update, ensure that the
power supply is within specification for the entire processing time
(see Table 1). Table 10 provides a memory map for all of the user
registers, which includes a column of flash backup information. A
yes in this column indicates that a register has a mirror location in
flash and, when backed up properly, automatically restores itself
during startup or after a reset. Figure 15 provides a diagram of
the dual memory structure that supports all device operations
and stores critical user settings.
NONVOLATILE
FLASH MEMORY
(NO SPI ACCESS)
MANUAL
FLASH
BACKUP
START-UP
RESET
VOLATILE
SRAM
SPI ACCESS
11855-012
Figure 15. SRAM and Flash Memory Diagram
READING SENSOR DATA
The ADIS16488A automatically starts up and activates Page 0
for data register access. Write 0x00 to the PAGE_ID register
(DIN = 0x8000) to activate Page 0 for data access after accessing
any other page.
A single register read requires two 16-bit SPI cycles. The first
cycle requests the contents of a register using the bit assignments in
Figure 13, and then the register contents follow DOUT during
the second sequence.
The first bit in a DIN command is zero, followed by either the
upper or lower address for the register. The last eight bits are
don’t care, but the SPI requires the full set of 16 SCLKs to
receive the request.
Figure 16 includes two register reads in succession, which starts
with DIN = 0x1A00, to request the contents of the Z_GYRO_OUT
register, and follows with 0x1800, to request the contents of the
Z_GYRO_LOW register.
DIN
DOUT
0x1A00 0x1800 NEXT
ADDRESS
Z_GYRO_OUT Z_GYRO_LOW
11855-013
Figure 16. SPI Read Example
Figure 17 provides an example of the four SPI signals when reading
PROD_ID in a repeating pattern. This is an effective pattern to use
for troubleshooting the SPI interface setup and communications
because the contents of PROD_ID are predefined and stable.
SCLK
CS
DIN
DOUT
DOUT = 0100 0000 0110 1000 = 0x4068 = 16,488 (PROD_ID)
DIN = 0111 1110 0000 0000 = 0x7E00
11855-014
Figure 17. SPI Read Example, Second 16-Bit Sequence
ADIS16488A Data Sheet
USER REGISTERS
Table 10. User Register Memory Map (N/A = Not Applicable)
Name R/W1 Flash PAGE_ID Address Default Register Description Format
PAGE_ID R/W No 0x00 0x00 0x00 Page identifier N/A
Reserved N/A N/A 0x00 0x02 to 0x04 N/A Reserved N/A
SEQ_CNT R No 0x00 0x06 N/A Sequence counter Table 57
SYS_E_FLAG R No 0x00 0x08 0x0000 Output, system error flags Table 48
DIAG_STS R No 0x00 0x0A 0x0000 Output, self test error flags Table 49
ALM_STS R No 0x00 0x0C 0x0000 Output, alarm error flags Table 50
TEMP_OUT R No 0x00 0x0E N/A Output, temperature Table 46
X_GYRO_LOW
R
No
0x00
0x10
N/A
Output, x-axis gyroscope, low word
Table 15
X_GYRO_OUT R No 0x00 0x12 N/A Output, x-axis gyroscope, high word Table 11
Y_GYRO_LOW R No 0x00 0x14 N/A Output, y-axis gyroscope, low word Table 16
Y_GYRO_OUT R No 0x00 0x16 N/A Output, y-axis gyroscope, high word Table 12
Z_GYRO_LOW R No 0x00 0x18 N/A Output, z-axis gyroscope, low word Table 17
Z_GYRO_OUT R No 0x00 0x1A N/A Output, z-axis gyroscope, high word Table 13
X_ACCL_LOW R No 0x00 0x1C N/A Output, x-axis accelerometer, low word Table 22
X_ACCL_OUT R No 0x00 0x1E N/A Output, x-axis accelerometer, high word Table 18
Y_ACCL_LOW R No 0x00 0x20 N/A Output, y-axis accelerometer, low word Table 23
Y_ACCL_OUT R No 0x00 0x22 N/A Output, y-axis accelerometer, high word Table 19
Z_ACCL_LOW R No 0x00 0x24 N/A Output, z-axis accelerometer, low word Table 24
Z_ACCL_OUT
R
No
0x00
0x26
N/A
Output, z-axis accelerometer, high word
Table 20
X_MAGN_OUT R No 0x00 0x28 N/A Output, x-axis magnetometer, high word Table 39
Y_MAGN_OUT R No 0x00 0x2A N/A Output, y-axis magnetometer, high word Table 40
Z_MAGN_OUT R No 0x00 0x2C N/A Output, z-axis magnetometer, high word Table 41
BAROM_LOW R No 0x00 0x2E N/A Output, barometer, low word Table 45
BAROM_OUT R No 0x00 0x30 N/A Output, barometer, high word Table 43
Reserved
N/A
N/A
0x00
0x32 to 0x3E
N/A
Reserved
N/A
X_DELTANG_LOW R No 0x00 0x40 N/A Output, x-axis delta angle, low word Table 29
X_DELTANG_OUT R No 0x00 0x42 N/A Output, x-axis delta angle, high word Table 25
Y_DELTANG_LOW R No 0x00 0x44 N/A Output, y-axis delta angle, low word Table 30
Y_DELTANG_OUT R No 0x00 0x46 N/A Output, y-axis delta angle, high word Table 26
Z_DELTANG_LOW
R
No
0x00
0x48
N/A
Output, z-axis delta angle, low word
Table 31
Z_DELTANG_OUT R No 0x00 0x4A N/A Output, z-axis delta angle, high word Table 27
X_DELTVEL_LOW R No 0x00 0x4C N/A Output, x-axis delta velocity, low word Table 36
X_DELTVEL_OUT R No 0x00 0x4E N/A Output, x-axis delta velocity, high word Table 32
Y_DELTVEL_LOW R No 0x00 0x50 N/A Output, y-axis delta velocity, low word Table 37
Y_DELTVEL_OUT R No 0x00 0x52 N/A Output, y-axis delta velocity, high word Table 33
Z_DELTVEL_LOW
R
No
0x00
0x54
N/A
Output, z-axis delta velocity, low word
Table 38
Z_DELTVEL_OUT R No 0x00 0x56 N/A Output, z-axis delta velocity, high word Table 34
Reserved N/A N/A 0x00 0x58 to 0x76 N/A Reserved N/A
TIME_MS_OUT R/W Yes 0x00 0x78 N/A Factory configuration time: minutes/seconds Table 125
TIME_DH_OUT R/W Yes 0x00 0x7A N/A Factory configuration date/time: day/hour Table 126
TIME_YM_OUT R/W Yes 0x00 0x7C N/A Factory configuration date: year/month Table 127
PROD_ID R Yes 0x00 0x7E 0x4068 Output, product identification (16,488) Table 54
Reserved N/A N/A 0x01 0x00 to 0x7E N/A Reserved N/A
PAGE_ID R/W No 0x02 0x00 0x00 Page identifier N/A
Reserved N/A N/A 0x02 0x02 N/A Reserved N/A
X_GYRO_SCALE R/W Yes 0x02 0x04 0x0000 Calibration, scale, x-axis gyroscope Table 72
Y_GYRO_SCALE
R/W
Yes
0x02
0x06
0x0000
Calibration, scale, y-axis gyroscope
Table 73
Z_GYRO_SCALE R/W Yes 0x02 0x08 0x0000 Calibration, scale, z-axis gyroscope Table 74
X_ACCL_SCALE R/W Yes 0x02 0x0A 0x0000 Calibration, scale, x-axis accelerometer Table 82
Y_ACCL_SCALE R/W Yes 0x02 0x0C 0x0000 Calibration, scale, y-axis accelerometer Table 83
Rev. C | Page 12 of 35
Data Sheet ADIS16488A
Name R/W1 Flash PAGE_ID Address Default Register Description Format
Z_ACCL_SCALE R/W Yes 0x02 0x0E 0x0000 Calibration, scale, z-axis accelerometer Table 84
XG_BIAS_LOW R/W Yes 0x02 0x10 0x0000 Calibration, offset, gyroscope, x-axis, low word Table 68
XG_BIAS_HIGH R/W Yes 0x02 0x12 0x0000 Calibration, offset, gyroscope, x-axis, high word Table 65
YG_BIAS_LOW R/W Yes 0x02 0x14 0x0000 Calibration, offset, gyroscope, y-axis, low word Table 69
YG_BIAS_HIGH
R/W
Yes
0x02
0x16
0x0000
Calibration, offset, gyroscope, y-axis, high word
Table 66
ZG_BIAS_LOW R/W Yes 0x02 0x18 0x0000 Calibration, offset, gyroscope, z-axis, low word Table 70
ZG_BIAS_HIGH R/W Yes 0x02 0x1A 0x0000 Calibration, offset, gyroscope, z-axis, high word Table 67
XA_BIAS_LOW R/W Yes 0x02 0x1C 0x0000 Calibration, offset, accelerometer, x-axis, low word Table 79
XA_BIAS_HIGH R/W Yes 0x02 0x1E 0x0000 Calibration, offset, accelerometer, x-axis, high word Table 76
YA_BIAS_LOW R/W Yes 0x02 0x20 0x0000 Calibration, offset, accelerometer, y-axis, low word Table 80
YA_BIAS_HIGH
R/W
Yes
0x02
0x22
0x0000
Calibration, offset, accelerometer, y-axis, high word
Table 77
ZA_BIAS_LOW R/W Yes 0x02 0x24 0x0000 Calibration, offset, accelerometer, z-axis, low word Table 81
ZA_BIAS_HIGH R/W Yes 0x02 0x26 0x0000 Calibration, offset, accelerometer, z-axis, high word Table 78
HARD_IRON_X R/W Yes 0x02 0x28 0x0000 Calibration, hard iron, magnetometer, x-axis Table 85
HARD_IRON_Y R/W Yes 0x02 0x2A 0x0000 Calibration, hard iron, magnetometer, y-axis Table 86
HARD_IRON_Z R/W Yes 0x02 0x2C 0x0000 Calibration, hard iron, magnetometer, z-axis Table 87
SOFT_IRON_S11 R/W Yes 0x02 0x2E 0x0000 Calibration, soft iron, magnetometer, S11 Table 89
SOFT_IRON_S12 R/W Yes 0x02 0x30 0x0000 Calibration, soft iron, magnetometer, S12 Table 90
SOFT_IRON_S13 R/W Yes 0x02 0x32 0x0000 Calibration, soft iron, magnetometer, S13 Table 91
SOFT_IRON_S21 R/W Yes 0x02 0x34 0x0000 Calibration, soft iron, magnetometer, S21 Table 92
SOFT_IRON_S22 R/W Yes 0x02 0x36 0x0000 Calibration, soft iron, magnetometer, S22 Table 93
SOFT_IRON_S23
R/W
Yes
0x02
0x38
0x0000
Calibration, soft iron, magnetometer, S23
Table 94
SOFT_IRON_S31 R/W Yes 0x02 0x3A 0x0000 Calibration, soft iron, magnetometer, S31 Table 95
SOFT_IRON_S32 R/W Yes 0x02 0x3C 0x0000 Calibration, soft iron, magnetometer, S32 Table 96
SOFT_IRON_S33 R/W Yes 0x02 0x3E 0x0000 Calibration, soft iron, magnetometer, S33 Table 97
BR_BIAS_LOW R/W Yes 0x02 0x40 0x0000 Calibration, offset, barometer, low word Table 100
BR_BIAS_HIGH R/W Yes 0x02 0x42 0x0000 Calibration, offset, barometer, high word Table 99
Reserved
N/A
N/A
0x02
0x44 to 0x72
N/A
Reserved
N/A
USER_SCR_1 R/W Yes 0x02 0x74 0x0000 User Scratch Register 1 Table 121
USER_SCR_2 R/W Yes 0x02 0x76 0x0000 User Scratch Register 2 Table 122
USER_SCR_3 R/W Yes 0x02 0x78 0x0000 User Scratch Register 3 Table 123
USER_SCR_4 R/W Yes 0x02 0x7A 0x0000 User Scratch Register 4 Table 124
FLSHCNT_LOW R Yes 0x02 0x7C N/A Diagnostic, flash memory count, low word Table 116
FLSHCNT_HIGH R Yes 0x02 0x7E N/A Diagnostic, flash memory count, high word Table 117
PAGE_ID R/W No 0x03 0x00 0x0000 Page identifier N/A
GLOB_CMD W No 0x03 0x02 N/A Control, global commands Table 115
Reserved N/A N/A 0x03 0x04 N/A Reserved N/A
FNCTIO_CTRL R/W Yes 0x03 0x06 0x000D Control, input/output pins, functional definitions Table 118
GPIO_CTRL
R/W
Yes
0x03
0x08
0x00X0
2
Control, input/output pins, general purpose
Table 119
CONFIG R/W Yes 0x03 0x0A 0x00C0 Control, clock, and miscellaneous correction Table 75
DEC_RATE R/W Yes 0x03 0x0C 0x0000 Control, output sample rate decimation Table 56
NULL_CNFG R/W Yes 0x03 0x0E 0x070A Control, automatic bias correction configuration Table 71
SLP_CNT R/W No 0x03 0x10 N/A Control, power-down/sleep mode Table 120
Reserved N/A N/A 0x03 0x12 to 0x14 N/A Reserved N/A
FILTR_BNK_0 R/W Yes 0x03 0x16 0x0000 Filter selection Table 58
FILTR_BNK_1 R/W Yes 0x03 0x18 0x0000 Filter selection Table 59
Reserved N/A N/A 0x03 0x1A to 0x1E N/A Reserved N/A
ALM_CNFG_0 R/W Yes 0x03 0x20 0x0000 Alarm configuration Table 111
ALM_CNFG_1 R/W Yes 0x03 0x22 0x0000 Alarm configuration Table 112
ALM_CNFG_2
R/W
Yes
0x03
0x24
0x0000
Alarm configuration
Table 113
Reserved N/A N/A 0x03 0x26 N/A Reserved N/A
XG_ALM_MAGN R/W Yes 0x03 0x28 0x0000 Alarm, x-axis gyroscope threshold setting Table 101
YG_ALM_MAGN R/W Yes 0x03 0x2A 0x0000 Alarm, y-axis gyroscope threshold setting Table 102
Rev. C | Page 13 of 35
ADIS16488A Data Sheet
Name R/W1 Flash PAGE_ID Address Default Register Description Format
ZG_ALM_MAGN R/W Yes 0x03 0x2C 0x0000 Alarm, z-axis gyroscope threshold setting Table 103
XA_ALM_MAGN R/W Yes 0x03 0x2E 0x0000 Alarm, x-axis accelerometer threshold Table 104
YA_ALM_MAGN R/W Yes 0x03 0x30 0x0000 Alarm, y-axis accelerometer threshold Table 105
ZA_ALM_MAGN R/W Yes 0x03 0x32 0x0000 Alarm, z-axis accelerometer threshold Table 106
XM_ALM_MAGN
R/W
Yes
0x03
0x34
0x0000
Alarm, x-axis magnetometer threshold
Table 107
YM_ALM_MAGN R/W Yes 0x03 0x36 0x0000 Alarm, y-axis magnetometer threshold Table 108
ZM_ALM_MAGN R/W Yes 0x03 0x38 0x0000 Alarm, z-axis magnetometer threshold Table 109
BR_ALM_MAGN R/W Yes 0x03 0x3A 0x0000 Alarm, barometer threshold setting Table 110
Reserved N/A N/A 0x03 0x3C to 0x76 N/A Reserved N/A
FIRM_REV R Yes 0x03 0x78 N/A Firmware revision Table 51
FIRM_DM
R
Yes
0x03
0x7A
N/A
Firmware programming date: day/month
Table 52
FIRM_Y R Yes 0x03 0x7C N/A Firmware programming date: year Table 53
Reserved N/A N/A 0x03 0x7E N/A Reserved N/A
Reserved N/A N/A 0x04 0x00 to 0x18 N/A Reserved N/A
SERIAL_NUM R Yes 0x04 0x20 N/A Serial number Table 55
Reserved N/A N/A 0x04 0x22 to 0x7F N/A Reserved N/A
PAGE_ID R/W No 0x05 0x00 0x0000 Page identifier N/A
FIR_COEF_Axxx R/W Yes 0x05 0x02 to 0x7E N/A FIR Filter Bank A, Coefficient 0 through Coefficient 59 Table 60
PAGE_ID R/W No 0x06 0x00 0x0000 Page identifier N/A
FIR_COEF_Axxx R/W Yes 0x06 0x02 to 0x7E N/A FIR Filter Bank A, Coefficient 60 through
Coefficient 119
Table 60
PAGE_ID
R/W
No
0x07
0x00
0x0000
Page identifier
N/A
FIR_COEF_Bxxx R/W Yes 0x07 0x02 to 0x7E N/A FIR Filter Bank B, Coefficient 0 through Coefficient 59 Table 61
PAGE_ID R/W No 0x08 0x00 0x0000 Page identifier N/A
FIR_COEF_Bxxx R/W Yes 0x08 0x02 to 0x7E N/A FIR Filter Bank B, Coefficient 60 through
Coefficient 119
Table 61
PAGE_ID R/W No 0x09 0x00 0x0000 Page identifier N/A
FIR_COEF_Cxxx R/W Yes 0x09 0x02 to 0x7E N/A FIR Filter Bank C, Coefficient 0 through Coefficient 59 Table 62
PAGE_ID R/W No 0x0A 0x00 0x0000 Page identifier N/A
FIR_COEF_Cxxx R/W Yes 0x0A 0x02 to 0x7E N/A FIR Filter Bank C, Coefficient 60 through
Coefficient 119
Table 62
PAGE_ID R/W No 0x0B 0x00 0x0000 Page identifier N/A
FIR_COEF_Dxxx R/W Yes 0x0B 0x02 to 0x7E N/A FIR Filter Bank D, Coefficient 0 through Coefficient 59 Table 63
PAGE_ID R/W No 0x0C 0x00 0x0000 Page identifier N/A
FIR_COEF_Dxxx R/W Yes 0x0C 0x02 to 0x7E N/A FIR Filter Bank D, Coefficient 60 through
Coefficient 119
Table 63
1 R is read only, W is write only, R/W is read and write, and N/A means not applicable.
2 The GPIO_CTRL[7:4] bits reflect the logic levels on the DIOx lines and do not have a default setting.
Rev. C | Page 14 of 35
Data Sheet ADIS16488A
Rev. C | Page 15 of 35
OUTPUT DATA REGISTERS
After the ADIS16488A completes its start-up process, the
PAGE_ID register contains 0x0000, which sets Page 0 as the
active page for SPI access. Page 0 contains the output data, real-
time clock, status, and product identification registers.
INERTIAL SENSOR DATA FORMAT
The gyroscope, accelerometer, delta angle, delta velocity, and
barometer output data registers use a 32-bit, twos complement
format. Each output uses two registers to support this resolution.
Figure 18 provides an example of how each register contributes
to each inertial measurement. In this case, X_GYRO_OUT is the
most significant word (upper 16 bits), and X_GYRO_LOW is the
least significant word (lower 16 bits). In many cases, using the
most significant word registers alone provides sufficient resolution
for preserving key performance metrics.
X-AXIS GYROSCOPE DATA
01515 0
X_GYRO_OUT X_GYRO_LOW
11855-016
Figure 18. Gyroscope Output Format Example, DEC_RATE > 0
The arrows in Figure 19 represent the direction of the motion,
which produces a positive output response in the output register
of each sensor. The accelerometers respond to both dynamic and
static forces associated with acceleration, including gravity. When
lying perfectly flat, as shown in Figure 19, the z-axis accelerometer
output is 1 g, and the x and y accelerometers are 0 g.
ROTATION RATE (GYROSCOPE)
The registers that use the x_GYRO_OUT format are the primary
registers for the gyroscope measurements (see Table 11, Table 12,
and Table 13). When processing data from these registers, use a
16-bit, twos complement data format. Table 14 provides
x_GYRO_OUT digital coding examples.
Table 11. X_GYRO_OUT (Page 0, Base Address = 0x12)
Bits Description
[15:0] X-axis gyroscope data; twos complement,
±450°/sec range, 0°/sec = 0x0000, 1 LSB = 0.02°/sec
Table 12. Y_GYRO_OUT (Page 0, Base Address = 0x16)
Bits Description
[15:0] Y-axis gyroscope data; twos complement,
±450°/sec range, 0°/sec = 0x0000, 1 LSB = 0.02°/sec
Table 13. Z_GYRO_OUT (Page 0, Base Address = 0x1A)
Bits Description
[15:0] Z-axis gyroscope data; twos complement,
±450°/sec range, 0°/sec = 0x0000, 1 LSB = 0.02°/sec
Table 14. x_GYRO_OUT Data Format Examples
Rotation Rate Decimal Hex Binary
+450°/sec +22,500 0x57E4 0101 0111 1110 0100
+0.04/sec +2 0x0002 0000 0000 0000 0010
+0.02°/sec +1 0x0001 0000 0000 0000 0001
0°/sec 0 0x0000 0000 0000 0000 0000
−0.02°/sec −1 0xFFFF 1111 1111 1111 1111
−0.04°/sec −2 0xFFFE 1111 1111 1111 1110
−450°/sec −22,500 0xA81C 1010 1000 0001 1100
The registers that use the x_GYRO_LOW naming format provide
additional resolution for the gyroscope measurements (see
Table 15, Table 16, and Table 17). The MSB has a weight of
0.01°/sec, and each subsequent bit has ½ the weight of the
previous one.
Table 15. X_GYRO_LOW (Page 0, Base Address = 0x10)
Bits Description
[15:0] X-axis gyroscope data; additional resolution bits
Table 16. Y_GYRO_LOW (Page 0, Base Address = 0x14)
Bits Description
[15:0] Y-axis gyroscope data; additional resolution bits
Table 17. Z_GYRO_LOW (Page 0, Base Address = 0x18)
Bits Description
[15:0] Z-axis gyroscope data; additional resolution bits
PIN 1
PIN 23
a
Y
m
Y
g
Y
Y-AXIS
g
X
X-AXIS
a
X
m
X
Z-AXIS
a
Z
m
Z
g
Z
11855-017
Figure 19. Inertial Sensor Direction Reference Diagram
ADIS16488A Data Sheet
ACCELERATION
The registers that use the x_ACCL_OUT format are the primary
registers for the accelerometer measurements (see Table 18,
Table 19, and Table 20). When processing data from these
registers, use a 16-bit, twos complement data format. Table 21
provides x_ACCL_OUT digital coding examples.
Table 18. X_ACCL_OUT (Page 0, Base Address = 0x1E)
Bits Description
[15:0] X-axis accelerometer data; twos complement,
±18 g range, 0 g = 0x0000, 1 LSB = 0.8 mg
Table 19. Y_ACCL_OUT (Page 0, Base Address = 0x22)
Bits Description
[15:0] Y-axis accelerometer data; twos complement,
±18 g range, 0 g = 0x0000, 1 LSB = 0.8 mg
Table 20. Z_ACCL_OUT (Page 0, Base Address = 0x26)
Bits Description
[15:0] Z-axis accelerometer data; twos complement,
±18 g range, 0 g = 0x0000, 1 LSB = 0.8 mg
Table 21. x_ACCL_OUT Data Format Examples
Acceleration Decimal Hex Binary
+18 g +22,500 0x57E4 0101 0111 1110 0100
+1.6 mg +2 0x0002 0000 0000 0000 0010
+0.8 mg +1 0x0001 0000 0000 0000 0001
0 mg 0 0x0000 0000 0000 0000 0000
−0.8 mg −1 0xFFFF 1111 1111 1111 1111
−1.6 mg −2 0xFFFE 1111 1111 1111 1110
−18 g −22,500 0xA81C 1010 1000 0001 1100
The registers that use the x_ACCL_LOW naming format provide
additional resolution for the accelerometer measurements (see
Table 22, Table 23, and Table 24). The MSB has a weight of 0.4 mg,
and each subsequent bit has ½ the weight of the previous one.
Table 22. X_ACCL_LOW (Page 0, Base Address = 0x1C)
Bits Description
[15:0] X-axis accelerometer data; additional resolution bits
Table 23. Y_ACCL_LOW (Page 0, Base Address = 0x20)
Bits Description
[15:0] Y-axis accelerometer data; additional resolution bits
Table 24. Z_ACCL_LOW (Page 0, Base Address = 0x24)
Bits Description
[15:0] Z-axis accelerometer data; additional resolution bits
DELTA ANGLES
The x_DELTANG_OUT registers are the primary output registers
for the delta angle calculations. When processing data from these
registers, use a 16-bit, twos complement data format (see Table 25,
Table 26, and Table 27). Table 28 provides x_DELTANG_OUT
digital coding examples.
The delta angle outputs represent an integration of the gyro-
scope measurements and use the following formula for all three
axes (x-axis displayed):
( )
∑
−
=−++ +×=∆ 1
0
1,,
,2
1D
d
dDnxdDnx
S
Dnx f
ωωθ
where:
D is the decimation rate = DEC_RATE + 1.
fs is the sample rate.
d is the incremental variable in the summation formula.
ωx is the x-axis rate of rotation (gyroscope).
n is the sample time, prior to the decimation filter.
When using the internal sample clock, fS is equal to 2460 SPS.
When using the external clock option, fS is equal to the frequency
of the external clock, which is limited to a minimum of 2 kHz,
to prevent overflow in the x_DELTANG_xxx registers at high
rotation rates. See Table 56 and Figure 20 for more information
on the DEC_RATE register (decimation filter).
The x_DELTANG_LOW registers (see Table 29, Table 30, and
Table 31) provide additional resolution bits for the delta angle and
combine with the x_DELTANG_OUT registers to provide a 32-bit,
twos complement number. The MSB in the x_DELTANG_LOW
registers have a weight of ~0.011° (720°/216), and each subsequent
bit carries a weight of ½ of the previous one.
Table 25. X_DELTANG_OUT (Page 0, Base Address = 0x42)
Bits Description
[15:0] X-axis delta angle data; twos complement,
±720° range, 0° = 0x0000, 1 LSB = 720°/215 = ~0.022°
Table 26. Y_DELTANG_OUT (Page 0, Base Address = 0x46)
Bits Description
[15:0] Y-axis delta angle data; twos complement,
±720° range, 0° = 0x0000, 1 LSB = 720°/215 = ~0.022°
Table 27. Z_DELTANG_OUT (Page 0, Base Address = 0x4A)
Bits Description
[15:0]
Z-axis delta angle data; twos complement,
±720° range, 0° = 0x0000, 1 LSB = 720°/215 = ~0.022°
Table 28. x_DELTANG_OUT Data Format Examples
Angle (°) Decimal Hex Binary
+720 × (215 − 1)/215 +32,767 0x7FFF 0111 1111 1110 1111
+1440/215 +2 0x0002 0000 0000 0000 0010
+720/215 +1 0x0001 0000 0000 0000 0001
0 0 0x0000 0000 0000 0000 0000
−720/2
15
−1
0xFFFF
1111 1111 1111 1111
−1440/215 −2 0xFFFE 1111 1111 1111 1110
−720 −32,768 0x8000 1000 0000 0000 0000
Table 29. X_DELTANG_LOW (Page 0, Base Address = 0x40)
Bits Description
[15:0] X-axis delta angle data; additional resolution bits
Rev. C | Page 16 of 35
Data Sheet ADIS16488A
Table 30. Y_DELTANG_LOW (Page 0, Base Address = 0x44)
Bits Description
[15:0] Y-axis delta angle data; additional resolution bits
Table 31. Z_DELTANG_LOW (Page 0, Base Address = 0x48)
Bits Description
[15:0] Z-axis delta angle data; additional resolution bits
DELTA VELOCITY
The registers that use the x_DELTVEL_OUT format are the
primary registers for the delta velocity calculations. When
processing data from these registers, use a 16-bit, twos
complement data format (see Table 32, Table 33, and Table 34).
Table 35 provides x_DELTVEL_OUT digital coding examples.
The delta velocity outputs represent an integration of the
accelerometer measurements and use the following formula for
all three axes (x-axis displayed):
( )
∑
−
=−+
+
+×
=∆
1
0
1,,
,
2
1
D
d
d
Dnx
dDnx
S
Dn
x
aa
f
V
where:
D is the decimation rate = DEC_RATE + 1.
fS is the sample rate.
d is the incremental variable in the summation formula.
ax is the x-axis linear acceleration.
n is the sample time, prior to the decimation filter.
When using the internal sample clock, fS is equal to 2460 SPS.
When using the external clock option, fS is equal to the frequency
of the external clock, which is limited to a minimum of 2 kHz,
to prevent overflow in the x_DELTVEL_xxx registers at high
rotation rates. See Table 56 and Figure 20 for more information
on the DEC_RATE register (decimation filter).
Table 32. X_DELTVEL_OUT (Page 0, Base Address = 0x4E)
Bits Description
[15:0] X-axis delta velocity data; twos complement, ±200 m/sec
range, 0 m/sec = 0x0000
1 LSB = 200 m/sec ÷ 2
15
= ~6.104 mm/sec
Table 33. Y_DELTVEL_OUT (Page 0, Base Address = 0x52)
Bits Description
[15:0] Y-axis delta velocity data; twos complement, ±200 m/sec
range, 0 m/sec = 0x0000
1 LSB = 200 m/sec ÷ 2
15
= ~6.104 mm/sec
Table 34. Z_DELTVEL_OUT (Page 0, Base Address = 0x56)
Bits Description
[15:0] Z-axis delta velocity data; twos complement, ±200 m/sec
range, 0 m/sec = 0x0000
1 LSB = 200 m/sec ÷ 215 = ~6.104 mm/sec
Table 35. x_DELTVEL_OUT, Data Format Examples
Velocity (m/sec) Decimal Hex Binary
+200 × (215 − 1)/215 +32,767 0x7FFF 0111 1111 1111 1111
+400/215 +2 0x0002 0000 0000 0000 0010
+200/215 +1 0x0001 0000 0000 0000 0001
0 0 0x0000 0000 0000 0000 0000
−200/215 −1 0xFFFF 1111 1111 1111 1111
−400/215 −2 0xFFFE 1111 1111 1111 1110
−200 −32,768 0x8000 1000 0000 0000 0000
The x_DELTVEL_LOW registers (see Table 36, Table 37, and
Table 38) provide additional resolution bits for the delta velocity and
combine with the x_DELTVEL_OUT registers to provide a 32-bit,
twos complement number. The MSB in the x_DELTVEL_LOW
registers have a weight of ~3.052 mm/sec (200 m/sec ÷ 216), and each
subsequent bit carries a weight of ½ of the previous one.
Table 36. X_DELTVEL_LOW (Page 0, Base Address = 0x4C)
Bits Description
[15:0] X-axis delta velocity data; additional resolution bits
Table 37. Y_DELTVEL_LOW (Page 0, Base Address = 0x50)
Bits Description
[15:0] Y-axis delta velocity data; additional resolution bits
Table 38. Z_DELTVEL_LOW (Page 0, Base Address = 0x54)
Bits Description
[15:0] Z-axis delta velocity data; additional resolution bits
MAGNETOMETERS
The registers that use the x_MAGN_OUT format are the primary
registers for the magnetometer measurements. When processing
data from these registers, use a 16-bit, twos complement data
format. Ta ble 39, Table 40, and Tabl e 41 provide the numerical
format for each register, and Table 42 provides x_MAGN_OUT
digital coding examples.
Table 39. X_MAGN_OUT (Page 0, Base Address = 0x28)
Bits Description
[15:0] X-axis magnetometer data; twos complement,
±3.2767 gauss range, 0 gauss = 0x0000,
1 LSB = 0.1 mgauss
Table 40. Y_MAGN_OUT (Page 0, Base Address = 0x2A)
Bits Description
[15:0] Y-axis magnetometer data; twos complement,
±3.2767 gauss range, 0 gauss = 0x0000,
1 LSB = 0.1 mgauss
Table 41. Z_MAGN_OUT (Page 0, Base Address = 0x2C)
Bits Description
[15:0] Z-axis magnetometer data; twos complement,
±3.2767 gauss range, 0 gauss = 0x0000,
1 LSB = 0.1 mgauss
Rev. C | Page 17 of 35
ADIS16488A Data Sheet
Table 42. x_MAGN_OUT Data Format Examples
Magnetic Field Decimal Hex Binary
+3.2767 gauss +32,767 0x7FFF 0111 1111 1111 1111
+0.2 mgauss +2 0x0002 0000 0000 0000 0010
+0.1 mgauss +1 0x0001 0000 0000 0000 0001
0 gauss 0 0x0000 0000 0000 0000 0000
−0.1 mgauss −1 0xFFFF 1111 1111 1111 1111
−0.2 mgauss −2 0xFFFE 1111 1111 1111 1110
−3.2768 gauss −32,768 0x8000 1000 0000 0000 0000
BAROMETER
The BAROM_OUT register (see Table 43) and BAROM_LOW
register (see Table 45) provide access to the barometric pressure
data. These two registers combine to provide a 32-bit, twos
complement format. Some applications can use BAROM_OUT
by itself. For cases where the finer resolution available from
BAROM_LOW is valuable, combine them in the same manner
as the gyroscopes (see Figure 18). When processing data from
the BAROM_OUT register alone, use a 16-bit, twos complement
data format. Table 43 provides the numerical format for BAROM_
OUT, and Table 44 provides digital coding examples.
Table 43. BAROM_OUT (Page 0, Base Address = 0x30)
Bits Description
[15:0] Barometric pressure; twos complement, ±1.31 bar range,
0 bar = 0x0000, 40 µbar/LSB
Table 44. BAROM_OUT Data Format Examples
Pressure (Bar)
Decimal
Hex
Binary
+0.00004 × (215 − 1) +32,767 0x7FFF 0111 1111 1110 1111
+0.00008
+2
0x0002
0000 0000 0000 0010
+0.00004 +1 0x0001 0000 0000 0000 0001
0 0 0x0000 0000 0000 0000 0000
−0.00004 −1 0xFFFF 1111 1111 1111 1111
−0.00008 −2 0xFFFE 1111 1111 1111 1110
−0.00004 × 215 −32,768 0x8000 1000 0000 0000 0000
The BAROM_LOW register provides additional resolution for
the barometric pressure measurement. The MSB has a weight of
20 μbar, and each subsequent bit carries a weight of ½ of the
previous one.
Table 45. BAROM_LOW (Page 0, Base Address = 0x2E)
Bits Description
[15:0] Barometric pressure; additional resolution bits
INTERNAL TEMPERATURE
The TEMP_OUT register provides an internal temperature
measurement for observing relative temperature changes inside
the ADIS16488A (see Table 46). Table 47 provides TEMP_OUT
digital coding examples. Note that this temperature reflects a
higher temperature than that of ambient temperature, due to
self heating.
Table 46. TEMP_OUT (Page 0, Base Address = 0x0E)
Bits Description
[15:0] Temperature data; twos complement, 0.00565°C per LSB,
25°C = 0x0000
Table 47. TEMP_OUT Data Format Examples
Temperature (°C) Decimal Hex Binary
+85 +10,619 0x297B 0010 1001 0111 1011
+25 + 0.0113 +2 0x0002 0000 0000 0000 0010
+25 + 0.00565
+1
0x0001
0000 0000 0000 0001
+25 0 0x0000 0000 0000 0000 0000
+25 − 0.00565 −1 0xFFFF 1111 1111 1111 1111
+25 − 0.0113 −2 0xFFFE 1111 1111 1111 1110
−40 −11,504 0xD310 1101 0011 0001 0000
STATUS/ALARM INDICATORS
The SYS_E_FLAG register in Table 48 provides the system error
flags and new data bits for the magnetometer and barometer
outputs. The new data flags trigger data collection of the
magnetometer and barometer (x_MAGN_OUT and BAROM_xxx
registers) because they update at a fixed rate that is not dependent
on the DEC_RATE setting.
Reading the SYS_E_FLAG register clears all of its error flags and
returns each bit to a zero value, with the exception of Bit 7. If
SYS_E_FLAG[7] is high, use the software reset (GLOB_CMD[7]
(see Table 115) to clear this condition and restore normal
operation. If any bit in the SYS_E_FLAG register is associated
with an error condition that remains after reading this register,
this bit automatically returns to an alarm value of 1.
Table 48. SYS_E_FLAG (Page 0, Base Address = 0x08)
Bits Description (Default = 0x0000)
[15] Watch dog timer flag (1 = timed out)
[14:10] Not used
9 New data flag, barometer (1 = new, unread data)1
8 New data flag, magnetometer (1 = new, unread data)2
7 Processing overrun (1 = error)
6 Flash memory update, result of GLOB_CMD[3] = 1
(1 = failed update, 0 = update successful)
5
Inertial self-test failure (1 = DIAG_STS ≠ 0x0000)
4 Sensor overrange (1 = at least one sensor overranged)
3 SPI communication error
(1 = error condition, when the number of SCLK pulses
is not equal to a multiple of 16)
[2:1] Not used
0 Alarm status flag (1 = ALM_STS ≠ 0x0000)
1 This flag restores to zero after reading the contents on BAROM_OUT.
2 This flag restores to zero after reading one x_MAGN_OUT register.
Rev. C | Page 18 of 35
Data Sheet ADIS16488A
The DIAG_STS register in Table 49 provides the flags for the
internal self test function, which is from GLOB_CMD[1] (see
Table 115). Note that the flag of the barometer, DIAG_STS[11],
updates only after start-up and reset operations and that reading
the DIAG_STS register causes all of its bits to restore to 0. The
bits only return to 1 if the error condition persists.
Table 49. DIAG_STS (Page 0, Base Address = 0x0A)
Bits Description (Default = 0x0000)
[15:12] Not used
11 Self test failure, barometer (1 = failed at start-up)
10 Self test failure, z-axis magnetometer (1 = failure)
9 Self test failure, y-axis magnetometer (1 = failure)
8 Self test failure, x-axis magnetometer (1 = failure)
[7:6]
Not used
5 Self test failure, z-axis accelerometer (1 = failure)
4 Self test failure, y-axis accelerometer (1 = failure)
3 Self test failure, x-axis accelerometer (1 = failure)
2 Self test failure, z-axis gyroscope (1 = failure)
1 Self test failure, y-axis gyroscope (1 = failure)
0 Self test failure, x-axis gyroscope (1 = failure)
The ALM_STS register in Table 50 provides the alarm bits for
the programmable alarm levels of each sensor. Note that reading
the ALM_STS register causes all of its bits to restore to 0. The
bits only return to 1 if the error condition persists.
Table 50. ALM_STS (Page 0, Base Address = 0x0C)
Bits
Description (Default = 0x0000)
[15:12] Not used
11
Barometer alarm flag (1 = alarm is active)
10 Z-axis magnetometer alarm flag (1 = alarm is active)
9 Y-axis magnetometer alarm flag (1 = alarm is active)
8 X-axis magnetometer alarm flag (1 = alarm is active)
[7:6] Not used
5 Z-axis accelerometer alarm flag (1 = alarm is active)
4
Y-axis accelerometer alarm flag (1 = alarm is active)
3 X-axis accelerometer alarm flag (1 = alarm is active)
2 Z-axis gyroscope alarm flag (1 = alarm is active)
1 Y-axis gyroscope alarm flag (1 = alarm is active)
0 X-axis gyroscope alarm flag (1 = alarm is active)
FIRMWARE REVISION
The FIRM_REV register (see Table 51) provides the firmware
revision for the internal firmware. This register uses a binary
coded decimal (BCD) format, where each nibble represents a
digit. For example, if FIRM_REV = 0x1234, the firmware
revision is 12.34. The tens digit is equal to 1, the ones digit is
equal to 2, the tenths digit is equal to 3, and the hundredths
digit is equal to 4.
Table 51. FIRM_REV (Page 3, Base Address = 0x78)
Bits Description
[15:12] Firmware revision BCD code, tens digit
Numerical format = 4-bit binary, range = 0 to 9
[11:8] Firmware revision BCD code, ones digit
Numerical format = 4-bit binary, range = 0 to 9
[7:4]
Firmware revision BCD code, tenths digit
Numerical format = 4-bit binary, range = 0 to 9
[3:0] Firmware revision BCD code, hundredths digit
Numerical format = 4-bit binary, range = 0 to 9
The FIRM_DM register (see Table 52) contains the month and
day of the factory configuration date. FIRM_DM[15:12] and
FIRM_DM[11:8] contain digits that represent the month of the
factory configuration in a BCD format. For example, November
is the 11th month in a year and is represented by FIRM_DM[15:8] =
0x11.
FIRM_DM[7:4] and FIRM_DM[3:0] contain digits that represent
the day of factory configuration in a BCD format. For example,
the 27th day of the month is represented by FIRM_DM[7:0] = 0x27.
Table 52. FIRM_DM (Page 3, Base Address = 0x7A)
Bits Description
[15:12] Factory configuration month BCD code, tens digit,
numerical format = 4-bit binary, range = 0 to 2
[11:8] Factory configuration month BCD code, ones digit,
numerical format = 4-bit binary, range = 0 to 9
[7:4] Factory configuration day BCD code, tens digit
Numerical format = 4-bit binary, range = 0 to 3
[3:0]
Factory configuration day BCD code, ones digit
Numerical format = 4-bit binary, range = 0 to 9
The FIRM_Y register (see Table 53) contains the year of the
factory configuration date. For example, the year, 2013, is
represented by FIRM_Y = 0x2013.
Table 53. FIRM_Y (Page 3, Base Address = 0x7C)
Bits Description
[15:12] Factory configuration year BCD code, thousands digit,
numerical format = 4-bit binary, range = 0 to 9
[11:8]
Factory configuration year BCD code, hundreds digit,
numerical format = 4-bit binary, range = 0 to 9
[7:4] Factory configuration year BCD code, tens digit,
numerical format = 4-bit binary, range = 0 to 3
[3:0] Factory configuration year BCD code, ones digit,
numerical format = 4-bit binary, range = 0 to 9
Rev. C | Page 19 of 35
ADIS16488A Data Sheet
PRODUCT IDENTIFICATION
The PROD_ID register (see Table 54) contains the binary
equivalent of the device number (16,488 = 0x4068), and the
SERIAL_NUM register (see Tabl e 55) contains a lot-specific
serial number.
Table 54. PROD_ID (Page 0, Base Address = 0x7E)
Bits Description (Default = 0x4068)
[15:0] Product identification = 0x4068
Table 55. SERIAL_NUM (Page 4, Base Address = 0x20)
Bits Description
[15:0] Lot-specific serial number
Rev. C | Page 20 of 35
Data Sheet ADIS16488A
DIGITAL SIGNAL PROCESSING
GYROSCOPES/ACCELEROMETERS
Figure 20 provides a signal flow diagram for all of the compo-
nents and settings that influence the frequency response for
the accelerometers and gyroscopes. The sample rate for each
accelerometer and gyroscope is 9.84 kHz. Each sensor has
its own averaging/decimation filter stage, which reduces the
update rate to 2.46 kSPS. When using the external clock option
(FNCTIO_CTRL[7:4], see Table 118), the input clock drives a
four-sample burst at a sample rate of 9.84 kSPS, which feeds
into the 4× averaging/decimation filter. This results in a data
rate that is equal to the input clock frequency.
AVERAGING/DECIMATION FILTER
The DEC_RATE register (see Table 56) provides user control for
the final filter stage (see Figure 20), which averages and decimates
the accelerometers, gyroscopes, delta angle, and delta velocity data.
The output sample rate is equal to 2460/(DEC_RATE + 1).
When using the external clock option (FNCTIO_CTRL[7:4], see
Table 118), replace the 2460 number in this relationship with the
input clock frequency. For example, turn to Page 3 (DIN = 0x8003),
and set DEC_RATE = 0x18 (DIN = 0x8C18, then DIN = 0x8D00)
to reduce the output sample rate to 98.4 SPS (2460 ÷ 25).
Table 56. DEC_RATE (Page 3, Base Address = 0x0C)
Bits Description (Default = 0x0000)
[15:11] Don’t care
[10:0] Decimation rate, binary format, maximum = 2047, see
Figure 20 for impact on sample rate
MAGNETOMETER/BAROMETER
When using the internal sampling clock, the magnetometer
output registers (x_MAGN_OUT) update at a rate of 102.5 SPS
and the barometer output registers (BAROM_xxx) update at a
rate of 51.25 SPS. When using the external clock, the magnet-
ometers update at a rate of 1/24th of the input clock frequency
and the barometers update at a rate that is 1/48th of the input
clock frequency.
The update rates for the magnetometer and barometers do not
change with the DEC_RATE register settings. SYS_E_FLAG[9:8]
(see Table 48) offers new data indicator bits that indicate fresh,
unread data is in the x_MAGN_OUT and BAROM_xxx registers.
The SEQ_CNT register provides a counter function to help
determine when there is new data in the magnetometer and
barometer registers.
When SEQ_CNT = 0x0001, there is new data in the magne-
tometer and barometer output registers. During initialization, the
SEQ_CNT register helps to synchronize read loops for new data in
both magnetometer and barometer outputs. When beginning a
continuous read loop, read SEQ_CNT, then subtract this value
from the maximum value shown (range) in Table 57 to predict
the number of internal sample cycles until both magnetometer
and barometer registers contain new data samples.
Table 57. SEQ_CNT (Page 0, Base Address = 0x06)
Bits Description
[15:11] Don’t care
[6:0] Binary counter: range = 1 to 48/(DEC_RATE + 1)
MEMS
SENSOR 330Hz ÷4
2.46kHz, fs
GYROSCOPE
2-PO LE: 404Hz , 757Hz
ACCELEROMETER
1-PO LE: 330Hz
4×
AVERAGE
DECIMATION
FILTER
SELECTABLE
FIR FILTER BANK
FILTR_BNK_0
FILTR_BNK_1
AVERAGE/DECIMATION FILTER
D = DEC_RAT E [ 10: 0] + 1
1
4
4
÷D
1
D
D
FIR
FILTER
BANK
fs
INTERNAL
CLOCK
9.84kHz
DIOx
OPTIONAL INPUT CLOCK
FNCTIO_CT RL[7] = 1
fs < 2400Hz
NOTES
1. WHEN F NCTI O_CTRL[7] = 1, EACH CL OCK PULSE O N THE DE S IG NATED DI Ox L INE (FNCT IO_CTRL [ 5: 4] ) S TART S A 4- S AM P LE BURST,
AT A SAMPL E RATE OF 9.84kHz. THE S E FO UR S AM P LES FEE D INT O THE 4x AV E RAGE/DECI M ATI ON FIL TER, WHI CH P RODUCES A
DATA RATE T HAT I S E QUAL TO THE I NP UT CL OCK FRE QUENCY .
11855-018
Figure 20. Sampling and Frequency Response Signal Flow
Rev. C | Page 21 of 35
ADIS16488A Data Sheet
FIR FILTER BANKS
The ADIS16488A provides four configurable, 120-tap FIR filter
banks. Each coefficient is 16 bits wide and occupies its own
register location for each page. When designing a FIR filter for
these banks, use a sample rate of 2.46 kHz and scale the coefficients
so that their sum equals 32,768. For filter designs that have less
than 120 taps, load the coefficients into the lower portion of the
filter and start with Coefficient 1. To prevent adding phase delay
to the response, ensure that all unused taps are equal to zero.
The FILTR_BNK_x registers provide three bits per sensor,
which configure the filter bank (A, B, C, D) and turn filtering
on and off. For example, turn to Page 3 (DIN = 0x8003), then
write 0x0057 to FILTR_BNK_0 (DIN = 0x9657, DIN = 0x9700)
to set the x-axis gyroscope to use the FIR filter in Bank D, to set
the y-axis gyroscope to use the FIR filter in Bank B, and to
enable these FIR filters in both x- and y-axis gyroscopes. Note
that the filter settings update after writing to the upper byte;
therefore, always configure the lower byte first. In cases that
require configuration to only the lower byte of either
FILTR_BNK_0 or FILTR_BNK_1, complete the process by
writing 0x00 to the upper byte.
Table 58. FILTR_BNK_0 (Page 3, Base Address = 0x16)
Bits Description (Default = 0x0000)
15 Don’t care
14 Y-axis accelerometer filter enable (1 = enabled)
[13:12]
Y-axis accelerometer filter bank selection:
00 = Bank A, 01 = Bank B, 10 = Bank C, 11 = Bank D
11 X-axis accelerometer filter enable (1 = enabled)
[10:9] X-axis accelerometer filter bank selection:
00 = Bank A, 01 = Bank B, 10 = Bank C, 11 = Bank D
8 Z-axis gyroscope filter enable (1 = enabled)
[7:6]
Z-axis gyroscope filter bank selection:
00 = Bank A, 01 = Bank B, 10 = Bank C, 11 = Bank D
5 Y-axis gyroscope filter enable (1 = enabled)
[4:3] Y-axis gyroscope filter bank selection:
00 = Bank A, 01 = Bank B, 10 = Bank C, 11 = Bank D
2
X-axis gyroscope filter enable (1 = enabled)
[1:0] X-axis gyroscope filter bank selection:
00 = Bank A, 01 = Bank B, 10 = Bank C, 11 = Bank D
Table 59. FILTR_BNK_1 (Page 3, Base Address = 0x18)
Bits Description (Default = 0x0000)
[15:12] Don’t care
11 Z-axis magnetometer filter enable (1 = enabled)
[10:9] Z-axis magnetometer filter bank selection:
00 = Bank A, 01 = Bank B, 10 = Bank C, 11 = Bank D
8 Y-axis magnetometer filter enable (1 = enabled)
[7:6] Y-axis magnetometer filter bank selection:
00 = Bank A, 01 = Bank B, 10 = Bank C, 11 = Bank D
5 X-axis magnetometer filter enable (1 = enabled)
[4:3] X-axis magnetometer filter bank selection:
00 = Bank A, 01 = Bank B, 10 = Bank C, 11 = Bank D
2 Z-axis accelerometer filter enable (1 = enabled)
[1:0] Z-axis accelerometer filter bank selection:
00 = Bank A, 01 = Bank B, 10 = Bank C, 11 = Bank D
Filter Memory Organization
Each filter bank uses two pages of the user register structure.
See Table 60, Table 61, Table 62, and Table 63 for the register
addresses in each filter bank.
Table 60. Filter Bank A Memory Map
Page PAGE_ID Address Register
5 0x05 0x00 PAGE_ID
5 0x05 0x02 to 0x07 Not used
5 0x05 0x08 FIR_COEF_A000
5 0x05 0x0A FIR_COEF_A001
5 0x05 0x0C to 0x7C FIR_COEF_A002 to
FIR_COEF_A058
5 0x05 0x7E FIR_COEF_A059
6 0x06 0x00 PAGE_ID
6 0x06 0x02 to 0x07 Not used
6
0x06
0x08
FIR_COEF_A060
6 0x06 0x0A FIR_COEF_A061
6 0x06 0x0C to 0x7C FIR_COEF_A062 to
FIR_COEF_A118
6 0x06 0x7E FIR_COEF_D119
Table 61. Filter Bank B Memory Map
Page PAGE_ID Address Register
7 0x07 0x00 PAGE_ID
7
0x07
0x02 to 0x07
Not used
7 0x07 0x08 FIR_COEF_B000
7 0x07 0x0A FIR_COEF_B001
7 0x07 0x0C to 0x7C FIR_COEF_B002 to
FIR_COEF_B058
7
0x07
0x7E
FIR_COEF_B059
8 0x08 0x00 PAGE_ID
8 0x08 0x02 to 0x07 Not used
8 0x08 0x08 FIR_COEF_B060
8 0x08 0x0A FIR_COEF_B061
8 0x08 0x0C to 0x7C FIR_COEF_B062 to
FIR_COEF_B118
8 0x08 0x7E FIR_COEF_B119
Rev. C | Page 22 of 35
Data Sheet ADIS16488A
Rev. C | Page 23 of 35
Table 62. Filter Bank C Memory Map
Page PAGE_ID Address Register
9 0x09 0x00 PAGE_ID
9 0x09 0x02 to 0x07 Not used
9 0x09 0x08 FIR_COEF_C000
9 0x09 0x0A FIR_COEF_C001
9 0x09 0x0C to 0x7C FIR_COEF_C002 to
FIR_COEF_C058
9 0x09 0x7E FIR_COEF_C059
10 0x0A 0x00 PAGE_ID
10 0x0A 0x02 to 0x07 Not used
10 0x0A 0x08 FIR_COEF_C060
10 0x0A 0x0A FIR_COEF_C061
10 0x0A 0x0C to 0x7C FIR_COEF_C062 to
FIR_COEF_C118
10 0x0A 0x7E FIR_COEF_C119
Table 63. Filter Bank D Memory Map
Page PAGE_ID Address Register
11 0x0B 0x00 PAGE_ID
11 0x0B 0x02 to 0x07 Not used
11 0x0B 0x08 FIR_COEF_D000
11 0x0B 0x0A FIR_COEF_D001
11 0x0B 0x0C to 0x7C FIR_COEF_D002 to
FIR_COEF_D058
11 0x0B 0x7E FIR_COEF_D059
12 0x0C 0x00 PAGE_ID
12 0x0C 0x02 to 0x07 Not used
12 0x0C 0x08 FIR_COEF_D060
12 0x0C 0x0A FIR_COEF_D061
12 0x0C 0x0C to 0x7C FIR_COEF_D062 to
FIR_COEF_D118
12 0x0C 0x7E FIR_COEF_D119
Default Filter Performance
The FIR filter banks have factory-programmed filter designs. They
are all low-pass filters that have unity dc gain. Table 64 provides
a summary of each filter design, and Figure 21 shows the frequency
response characteristics. The phase delay is equal to ½ of the total
number of taps.
Table 64. FIR Filter Descriptions, Default Configuration
FIR Filter Bank Taps −3 dB Frequency (Hz)
A 120 310
B 120 55
C 32 275
D 32 63
NO FIR
FILTERING
0
–10
–20
MAGNITUDE (dB)
–30
–40
–50
–60
–70
–80
–90
–100 0 200 400 600 800 1000 1200
FREQUENCY (Hz)
ADCB
11855-019
Figure 21. FIR Filter Frequency Response Curves
ADIS16488A Data Sheet
Rev. C | Page 24 of 35
CALIBRATION
The ADIS16488A factory calibration produces correction
formulas for the gyroscopes, accelerometers, magnetometers, and
barometers, and then programs them into the flash memory. In
addition, there are a series of user configurable calibration
registers for in-system tuning.
GYROSCOPES
The user calibration for the gyroscopes includes registers for
adjusting bias and sensitivity, as shown in Figure 22.
X-AXIS
GYRO
FACTORY
CALIBRATION
AND
FILTERING
X_GYRO_OUT X_GYRO_LOW
XG_BIAS_HIGH XG_BIAS_LOW
1 + X_GYRO_SCALE
11855-020
Figure 22. User Calibration Signal Path, Gyroscopes
Manual Bias Correction
The xG_BIAS_HIGH registers (see Table 65, Table 66, and
Table 67) and xG_BIAS_LOW registers (see Table 68, Table 69,
and Table 70) provide a bias adjustment function for the output
of each gyroscope sensor.
Table 65. XG_BIAS_HIGH (Page 2, Base Address = 0x12)
Bits Description (Default = 0x0000)
[15:0] X-axis gyroscope offset correction, upper word
twos complement, 0°/sec = 0x0000, 1 LSB = 0.02°/sec
Table 66. YG_BIAS_HIGH (Page 2, Base Address = 0x16)
Bits Description (Default = 0x0000)
[15:0] Y-axis gyroscope offset correction, upper word;
twos complement, 0°/sec = 0x0000, 1 LSB = 0.02°/sec
Table 67. ZG_BIAS_HIGH (Page 2, Base Address = 0x1A)
Bits Description (Default = 0x0000)
[15:0] Z-axis gyroscope offset correction, upper word;
twos complement, 0°/sec = 0x0000, 1 LSB = 0.02°/sec
Table 68. XG_BIAS_LOW (Page 2, Base Address = 0x10)
Bits Description (Default = 0x0000)
[15:0] X-axis gyroscope offset correction, lower word;
twos complement, 0°/sec = 0x0000,
1 LSB = 0.02°/sec ÷ 216 = ~0.000000305°/sec
Table 69. YG_BIAS_LOW (Page 2, Base Address = 0x14)
Bits Description (Default = 0x0000)
[15:0] Y-axis gyroscope offset correction, lower word;
twos complement, 0°/sec = 0x0000,
1 LSB = 0.02°/sec ÷ 216 = ~0.000000305°/sec
Table 70. ZG_BIAS_LOW (Page 2, Base Address = 0x18)
Bits Description (Default = 0x0000)
[15:0] Z-axis gyroscope offset correction, lower word
twos complement, 0°/sec = 0x0000,
1 LSB = 0.02°/sec ÷ 216 = ~0.000000305°/sec
Bias Null Command
The continuous bias estimator (CBE) accumulates and
averages data in a 64-sample FIFO. The average time (tA)
for the bias estimates relies on the sample time base setting in
NULL_CNFG[3:0] (see Table 71). Using the bias null command in
GLOB_CMD[0] (see Table 115), load the correction factors of the
CBE into the gyroscope offset correction registers (see Table 65,
Table 66, Table 67, Tabl e 68, Table 69, and Table 70). O n / of f
controls for the sensors, provided by NULL_CNFG[13:8],
update when issuing a bias null command. The factory default
configuration for NULL_CNFG enables the bias null command
for the gyroscopes, disables the bias null command for the accel-
erometers, and establishes the average time to ~26.64 seconds.
Table 71. NULL_CNFG (Page 3, Base Address = 0x0E)
Bits Description (Default = 0x070A)
[15:14] Not used
13 Z-axis acceleration bias correction enable (1 = enabled)
12 Y-axis acceleration bias correction enable (1 = enabled)
11 X-axis acceleration bias correction enable (1 = enabled)
10 Z-axis gyroscope bias correction enable (1 = enabled)
9 Y-axis gyroscope bias correction enable (1 = enabled)
8 X-axis gyroscope bias correction enable (1 = enabled)
[7:4] Not used
[3:0] Time base control (TBC), range: 0 to 13 (default = 10);
tB = 2TBC/2460, time base
tA = 64 × tB, average time
Turn to Page 3 (DIN = 0x8003) and set GLOB_CMD[0] = 1
(DIN = 0x8201, then DIN = 0x8300) to update the user offset
registers with the correction factors of the CBE. Ensure that the
inertial platform is stable during the entire average time for optimal
bias estimates.
Manual Sensitivity Correction
The x_GYRO_SCALE registers enable sensitivity adjustment
(see Table 72, Table 73, and Table 74).
Table 72. X_GYRO_SCALE (Page 2, Base Address = 0x04)
Bits Description (Default = 0x0000)
[15:0] X-axis gyroscope scale correction; twos complement,
0x0000 = unity gain, 1 LSB = 1 ÷ 215 = ~0.003052%
Table 73. Y_GYRO_SCALE (Page 2, Base Address = 0x06)
Bits Description (Default = 0x0000)
[15:0] Y-axis gyroscope scale correction; twos complement,
0x0000 = unity gain, 1 LSB = 1 ÷ 215 = ~0.003052%
Table 74. Z_GYRO_SCALE (Page 2, Base Address = 0x08)
Bits Description (Default = 0x0000)
[15:0] Z-axis gyroscope scale correction; twos complement,
0x0000 = unity gain, 1 LSB = 1 ÷ 215 = ~0.003052%
Data Sheet ADIS16488A
Rev. C | Page 25 of 35
Linear Acceleration on Effect on Gyroscope Bias
MEMS gyroscopes typically have a bias response to linear
acceleration that is normal to their axis of rotation. The
ADIS16488A offers an optional compensation function for this
effect; the factory default setting (0x00C0) for the CONFIG
register enables this function. To turn it off, turn to Page 3 (DIN
= 0x8003) and set CONFIG[7] = 0 (DIN = 0x8A40, DIN =
0x8B00). Note that this also keeps the point of percussion
alignment function enabled.
Table 75. CONFIG (Page 3, Base Address = 0x0A)
Bits Description (Default = 0x00C0)
[15:8] Not used
7 Linear-g compensation for gyroscopes (1 = enabled)
6 Point of percussion alignment (1 = enabled)
[5:2] Not used
1 Real-time clock, daylight savings time
(1: enabled, 0: disabled)
0 Real-time clock control
(1: relative/elapsed timer mode, 0: calendar mode)
ACCELEROMETERS
The user calibration for the accelerometers includes registers for
adjusting bias and sensitivity, as shown in Figure 23.
X-AXIS
ACCL
FACTORY
CALIBRATION
AND
FILTERING
X_ACCL_OUT X_ACCL_LOW
XA_BIAS_HIGH XA_BIAS_LOW
1 + X_ACCL_SCALE
11855-021
Figure 23. User Calibration Signal Path, Gyroscopes
Manual Bias Correction
The xA_BIAS_HIGH (see Table 76, Table 77, and Table 78) and
xA_BIAS_LOW (see Table 79, Table 80, and Table 81) registers
provide a bias adjustment function for the output of each accel-
erometer sensor. The xA_BIAS_HIGH registers use the same
format as x_ACCL_OUT registers. The xA_BIAS_LOW
registers use the same format as x_ACCL_LOW registers.
Table 76. XA_BIAS_HIGH (Page 2, Base Address = 0x1E)
Bits Description (Default = 0x0000)
[15:0] X-axis accelerometer offset correction, high word,
twos complement, 0 g = 0x0000, 1 LSB = 0.8 mg
Table 77. YA_BIAS_HIGH (Page 2, Base Address = 0x22)
Bits Description (Default = 0x0000)
[15:0] Y-axis accelerometer offset correction, high word,
twos complement, 0 g = 0x0000, 1 LSB = 0.8 mg
Table 78. ZA_BIAS_HIGH (Page 2, Base Address = 0x26)
Bits Description (Default = 0x0000)
[15:0] Z-axis accelerometer offset correction, high word,
twos complement, 0 g = 0x0000, 1 LSB = 0.8 mg
Table 79. XA_BIAS_LOW (Page 2, Base Address = 0x1C)
Bits Description (Default = 0x0000)
[15:0] X-axis accelerometer offset correction, low word,
twos complement, 0 g = 0x0000,
1 LSB = 0.8 mg ÷ 216 = ~0.0000122 mg
Table 80. YA_BIAS_LOW (Page 2, Base Address = 0x20)
Bits Description (Default = 0x0000)
[15:0] Y-axis accelerometer offset correction, low word,
twos complement, 0 g = 0x0000,
1 LSB = 0.8 mg ÷ 216 = ~0.0000122 mg
Table 81. ZA_BIAS_LOW (Page 2, Base Address = 0x24)
Bits Description (Default = 0x0000)
[15:0] Z-axis accelerometer offset correction, low word;,
twos complement, 0 g = 0x0000,
1 LSB = 0.8 mg ÷ 216 = ~0.0000122 mg
Manual Sensitivity Correction
The x_ACCL_SCALE registers enable sensitivity adjustment
(see Table 82, Table 83, Table 84).
Table 82. X_ACCL_SCALE (Page 2, Base Address = 0x0A)
Bits Description (Default = 0x0000)
[15:0] X-axis accelerometer scale correction,
twos complement, 0x0000 = unity gain,
1 LSB = 1 ÷ 215 = ~0.003052%
Table 83. Y_ACCL_SCALE (Page 2, Base Address = 0x0C)
Bits Description (Default = 0x0000)
[15:0] Y-axis accelerometer scale correction,
twos complement, 0x0000 = unity gain,
1 LSB = 1 ÷ 215 = ~0.003052%
Table 84. Z_ACCL_SCALE (Page 2, Base Address = 0x0E)
Bits Description (Default = 0x0000)
[15:0] Z-axis accelerometer scale correction,
twos complement, 0x0000 = unity gain,
1 LSB = 1 ÷ 215 = ~0.003052%
MAGNETOMETERS
The user calibration registers enable both hard iron and soft
iron correction, as shown in the following relationship:
H
H
H
M
M
M
S
SS
S
S
S
SS
S
M
M
M
Z
Y
X
Z
Y
X
ZC
YC
XC
1
1
1
33
3231
23
22
21
1312
11
where the MX, MY, and MZ variables represent the magnetometer
data prior to application of the user correction formula, and the
MXC, MYC, and MZC represent the magnetometer data after the
application of the user correction formula.
ADIS16488A Data Sheet
Hard Iron Correction
Table 85, Table 86, and Table 87 describe the register format for
the hard iron correction factors: HX, HY, and HZ. These registers
use a twos complement format. Table 88 provides some numerical
examples for converting the digital codes for these registers into
their decimal equivalent.
Table 85. HARD_IRON_X (Page 2, Base Address = 0x28)
Bits Description (Default = 0x0000)
[15:0] X-axis magnetometer hard iron correction factor, HX,
twos complement, ±3.2767 gauss range,
0.1 mgauss/LSB, 0 gauss = 0x0000 (see Table 88)
Table 86. HARD_IRON_Y (Page 2, Base Address = 0x2A)
Bits Description (Default = 0x0000)
[15:0] Y-axis magnetometer hard iron correction factor, HY,
twos complement, ±3.2767 gauss range,
0.1 mgauss/LSB, 0 gauss = 0x0000 (see Table 88)
Table 87. HARD_IRON_Z (Page 2, Base Address = 0x2C)
Bits Description (Default = 0x0000)
[15:0] Z-axis magnetometer hard iron correction factor, Hz,
twos complement, ±3.2767 gauss range,
0.1 mgauss/LSB, 0 gauss = 0x0000 (see Table 88)
Table 88. HARD_IRON_x Numerical Examples
Magnetic Field Decimal Hex Binary
+3.2767 gauss +32,767 0x7FFF 0111 1111 1111 1111
+0.2 mgauss
+2
0x0002
0000 0000 0000 0010
+0.1 mgauss +1 0x0001 0000 0000 0000 0001
0 gauss 0 0x0000 0000 0000 0000 0000
−0.1 mgauss −1 0xFFFF 1111 1111 1111 1111
−0.2 mgauss −2 0xFFFE 1111 1111 1111 1110
−3.2768 gauss −32,768 0x8000 1000 0000 0000 0000
Soft Iron Correction Matrix
The soft iron correction matrix contains correction factors for
both sensitivity (S11, S22, S33) and alignment (S12, S13, S21, S23, S31,
S32). The registers that represent each soft iron correction factor
are in Table 89 (S11), Tabl e 90 (S12), Table 91 (S13), Table 92 (S21),
Table 93 (S22), Table 94 (S23), Table 95 (S31), Table 96 (S32), and
Table 97 (S33). Table 98 offers some numerical examples for
converting between the digital codes and their effect on the
magnetometer output, in terms of percent change.
Table 89. SOFT_IRON_S11 (Page 2, Base Address = 0x2E)
Bits Description (Default = 0x0000)
[15:0] Magnetometer soft iron correction factor, S11,
twos complement format, see Table 98 for examples
Table 90. SOFT_IRON_S12 (Page 2, Base Address = 0x30)
Bits Description (Default = 0x0000)
[15:0] Magnetometer soft iron correction factor, S12,
twos complement format, see Table 98 for examples
Table 91. SOFT_IRON_S13 (Page 2, Base Address = 0x32)
Bits Description (Default = 0x0000)
[15:0] Magnetometer soft iron correction factor, S13,
twos complement format, see Table 98 for examples
Table 92. SOFT_IRON_S21 (Page 2, Base Address = 0x34)
Bits Description (Default = 0x0000)
[15:0]
Magnetometer soft iron correction factor, S
21
, twos
complement format, see Table 98 for examples
Table 93. SOFT_IRON_S22 (Page 2, Base Address = 0x36)
Bits Description (Default = 0x0000)
[15:0] Magnetometer soft iron correction factor, S22,
twos complement format, see Table 98 for examples
Table 94. SOFT_IRON_S23 (Page 2, Base Address = 0x38)
Bits Description (Default = 0x0000)
[15:0] Magnetometer soft iron correction factor, S23,
twos complement format, see Table 98 for examples
Table 95. SOFT_IRON_S31 (Page 2, Base Address = 0x3A)
Bits Description (Default = 0x0000)
[15:0] Magnetometer soft-iron correction factor, S31,
twos complement format, see Table 98 for examples
Table 96. SOFT_IRON_S32 (Page 2, Base Address = 0x3C)
Bits Description (Default = 0x0000)
[15:0] Magnetometer soft iron correction factor, S32,
twos complement format, see Table 98 for examples
Table 97. SOFT_IRON_S33 (Page 2, Base Address = 0x3E)
Bits Description (Default = 0x0000)
[15:0] Magnetometer soft iron correction factor, S33,
twos complement format, see Table 98 for examples
Table 98. Soft Iron Correction, Numerical Examples
Delta (%) Decimal Hex Binary
+100 – 1/216 +32,767 0x7FFF 0111 1111 1111 1111
+200/2
15
+2
0x0002
0000 0000 0000 0010
+100/215 +1 0x0001 0000 0000 0000 0001
0 0 0x0000 0000 0000 0000 0000
−100/215 −1 0xFFFF 1111 1111 1111 1111
−200/215 −2 0xFFFE 1111 1111 1111 1110
−100 −32,768 0x8000 1000 0000 0000 0000
Rev. C | Page 26 of 35
Data Sheet ADIS16488A
BAROMETERS
The BR_BIAS_HIGH register (see Table 99) and BR_BIAS_LOW
register (Table 100) provide an offset control function and use
the same format as the output registers, BAROM_OUT and
BAROM_LOW.
Table 99. BR_BIAS_HIGH (Page 2, Base Address = 0x42)
Bits Description (Default = 0x0000)
[15:0] Barometric pressure bias correction factor, high word,
twos complement, ±1.3 bar measurement range,
0 bar = 0x0000, 1 LSB = 40 µbar
Table 100. BR_BIAS_LOW (Page 2, Base Address = 0x40)
Bits Description (Default = 0x0000)
[15:0]
Barometric pressure bias correction factor, low word,
twos complement, ±1.3 bar measurement range,
0 bar = 0x0000, 1 LSB = 40 µbar ÷ 216 = ~0.00061 µbar
RESTORING FACTORY CALIBRATION
Turn to Page 3 (DIN = 0x8003) and set GLOB_CMD[6] = 1
(DIN = 0x8240, DIN = 0x8300) to execute the factory calibration
restore function. This function resets each user calibration register
to 0, resets all sensor data to 0, and automatically updates the
flash memory within 72 ms. See Table 115 for more information
on GLOB_CMD.
POINT OF PERCUSSION ALIGNMENT
CONFIG[6] offers a point of percussion alignment function
that maps the accelerometer sensors to the corner of the package
identified in Figure 24. To activate this feature, turn to Page 3
(DIN = 0x8003), then set CONFIG[6] = 1 (DIN = 0x8A40,
DIN = 0x8B00). See Table 75 for more information on the
CONFIG register.
PIN 1
PIN 23
POINT OF PERCUSSION
ALI GNME NT REFERENCE P OI NT.
SEE CONFIG[6].
11855-022
Figure 24. Point of Percussion Reference Point
Rev. C | Page 27 of 35
ADIS16488A Data Sheet
ALARMS
Each sensor has an independent alarm function that provides
controls for alarm magnitude, polarity, and enabling a dynamic
rate-of-change option. The ALM_STS register (see Table 50)
contains the alarm output flags and the FNCTIO_CTRL register
(see Table 118) provides an option for configuring one of the
digital input/output lines as an alarm indicator.
STATIC ALARM USE
The static alarm setting compares the output of each sensor
with the trigger settings in the xx_ALM_MAGN registers (see
Table 101 through Table 110) of that sensor.
Table 101. XG_ALM_MAGN (Page 3, Base Address = 0x28)
Bits Description (Default = 0x0000)
[15:0] X-axis gyroscope alarm threshold settings,
twos complement, 0°/sec = 0x0000, 1 LSB = 0.02°/sec
Table 102. YG_ALM_MAGN (Page 3, Base Address = 0x2A)
Bits Description (Default = 0x0000)
[15:0] Y-axis gyroscope alarm threshold settings,
twos complement, 0°/sec = 0x0000, 1 LSB = 0.02°/sec
Table 103. ZG_ALM_MAGN (Page 3, Base Address = 0x2C)
Bits Description (Default = 0x0000)
[15:0] Z-axis gyroscope alarm threshold settings,
twos complement, 0°/sec = 0x0000, 1 LSB = 0.02°/sec
Table 104. XA_ALM_MAGN (Page 3, Base Address = 0x2E)
Bits Description (Default = 0x0000)
[15:0] X-axis accelerometer alarm threshold settings,
twos complement, 0 g = 0x0000, 1 LSB = 0.8 mg
Table 105. YA_ALM_MAGN (Page 3, Base Address = 0x30)
Bits
Description (Default = 0x0000)
[15:0] Y-axis accelerometer alarm threshold settings,
twos complement, 0 g = 0x0000, 1 LSB = 0.8 mg
Table 106. ZA_ALM_MAGN (Page 3, Base Address = 0x32)
Bits Description (Default = 0x0000)
[15:0] Z-axis accelerometer alarm threshold settings,
twos complement, 0 g = 0x0000, 1 LSB = 0.8 mg
Table 107. XM_ALM_MAGN (Page 3, Base Address = 0x34)
Bits Description (Default = 0x0000)
[15:0] X-axis magnetometer alarm threshold settings,
twos complement, 0 gauss = 0x0000,
1 LSB = 0.1 mgauss
Table 108. YM_ALM_MAGN (Page 3, Base Address = 0x36)
Bits Description (Default = 0x0000)
[15:0] Y-axis magnetometer alarm threshold settings,
twos complement, 0 gauss = 0x0000,
1 LSB = 0.1 mgauss
Table 109. ZM_ALM_MAGN (Page 3, Base Address = 0x38)
Bits Description (Default = 0x0000)
[15:0] Z-axis magnetometer alarm threshold settings,
twos complement, 0 gauss = 0x0000,
1 LSB = 0.1 mgauss
Table 110. BR_ALM_MAGN (Page 3, Base Address = 0x3A)
Bits Description (Default = 0x0000)
[15:0] Z-axis barometer alarm threshold settings,
twos complement, 0 bar = 0x0000, 1 LSB = 40 µbar
Static Alarm Polarity Controls
The alarm polarity settings, located in the ALM_CNFG_x
registers (see Table 111 to Table 113), establish the relationship
for the condition that causes the corresponding alarm flag to be
active. For example, when ALM_CNFG_0[13] = 1, the alarm
flag for the x-axis accelerometer (ALM_STS[3], see Table 50)
becomes active (equal to 1) when X_ACCL_OUT is greater
than XA_ALM_MAGN.
Table 111. ALM_CNFG_0 (Page 3, Base Address = 0x20)
Bits Description (Default = 0x0000)
15 X-axis accelerometer alarm (1 = enabled)
14 Not used
13 X-axis accelerometer alarm polarity (1 = greater than)
12 X-axis accelerometer dynamic enable (1 = enabled)
11 Z-axis gyroscope alarm (1 = enabled)
10 Not used
9 Z-axis gyroscope alarm polarity (1 = greater than)
8 Z-axis gyroscope dynamic enable (1 = enabled)
7 Y-axis gyroscope alarm (1 = enabled)
6
Not used
5 Y-axis gyroscope alarm polarity (1 = greater than)
4 Y-axis gyroscope dynamic enable (1 = enabled)
3 X-axis gyroscope alarm (1 = enabled)
2 Not used
1 X-axis gyroscope alarm polarity (1 = greater than)
0
X-axis gyroscope dynamic enable (1 = enabled)
Rev. C | Page 28 of 35
Data Sheet ADIS16488A
Table 112. ALM_CNFG_1 (Page 3, Base Address = 0x22)
Bits Description (Default = 0x0000)
15 Y-axis magnetometer alarm (1 = enabled)
14 Not used
13 Y-axis magnetometer alarm polarity (1 = greater than)
12 Y-axis magnetometer dynamic enable (1 = enabled)
11 X-axis magnetometer (1 = enabled)
10 Not used
9 X-axis magnetometer alarm polarity (1 = greater than)
8 X-axis magnetometer dynamic enable (1 = enabled)
7 Z-axis accelerometer alarm (1 = enabled)
6
Not used
5 Z-axis accelerometer alarm polarity (1 = greater than)
4 Z-axis accelerometer dynamic enable (1 = enabled)
3 Y-axis accelerometer alarm (1 = enabled)
2 Not used
1 Y-axis accelerometer alarm polarity (1 = greater than)
0
Y-axis accelerometer dynamic enable (1 = enabled)
Table 113. ALM_CNFG_2 (Page 3, Base Address = 0x24)
Bits Description (Default = 0x0000)
[15:8] Not used
7 Barometer alarm (1 = enabled)
6 Not used
5 Barometer alarm polarity (1 = greater than)
4 Barometer dynamic enable (1 = enabled)
3 Z-axis magnetometer alarm (1 = enabled)
2 Not used
1 Z-axis magnetometer alarm polarity (1 = greater than)
0 Z-axis magnetometer dynamic enable (1 = enabled)
DYNAMIC ALARM USE
The dynamic alarm setting provides the option to compare the
change in the output of each sensor over a period of 48.7 ms with
that sensor’s xx_ALM_MAGN register.
Alarm Example
Table 114 offers an alarm configuration example, which sets the
z-axis gyroscope alarm to trip when Z_GYRO_OUT > 131.1°/sec
(0x199B).
Table 114. Alarm Configuration Example
DIN Description
0xAC9B Set ZG_ALM_MAGN[7:0] = 0x9B
0xAD19 Set ZG_ALM_MAGN[15:8] = 0x19
0xA000 Set ALM_CNFG_0[7:0] = 0x00
0xA103 Set ALM_CNFG_0[15:8] = 0x03
Rev. C | Page 29 of 35
ADIS16488A Data Sheet
SYSTEM CONTROLS
The ADIS16488A provides a number of system level controls for
managing its operation, which include reset, self test, calibration,
memory management, and input/output configuration.
GLOBAL COMMANDS
The GLOB_CMD register (see Tabl e 115) provides trigger bits for
several operations. Write 1 to the appropriate bit in GLOB_CMD to
start a function. After the function completes, the bit restores to 0.
Table 115. GLOB_CMD (Page 3, Base Address = 0x02)
Bits Description Execution Time
[15:8] Not used Not applicable
7 Software reset 120 ms
6 Factory calibration restore 75 ms
[5:4] Not used Not applicable
3 Flash memory update 375 ms
2
Flash memory test
50 ms
1 Self test 12 ms
0 Bias null See Table 71
Software Reset
Turn to Page 3 (DIN = 0x8003) and then set GLOB_CMD[7] = 1
(DIN = 0x8280, DIN = 0x8300) to reset the operation, which
removes all data, initializes all registers from their flash settings,
and starts data collection. This function provides a firmware
alternative to the RST pin (see Table 6, Pin 8).
Automatic Self-Test
Turn to Page 3 (DIN = 0x8003) and then set GLOB_CMD[1] = 1
(DIN = 0x8202, then DIN = 0x8300) to run an automatic self
test routine, which executes the following steps:
1. Measure the output on each sensor.
2. Activate the self test on each sensor.
3. Measure the output on each sensor.
4. Deactivate the self test on each sensor.
5. Calculate the difference with self test on and off.
6. Compare the difference with internal pass/fail criteria.
7. Report the pass/fail results for each sensor in DIAG_STS.
After waiting 12 ms for this test to complete, turn to Page 0
(DIN = 0x8000) and read DIAG_STS using DIN = 0x0A00.
Using an external clock can extend this time. When using an
external clock of 100 Hz, this time extends to 35 ms. Note that
100 Hz is too slow for optimal sensor performance.
MEMORY MANAGEMENT
The data retention of the flash memory depends on temperature
and the number of write cycles. Figure 25 characterizes the
dependence on temperature, and the FLSHCNT_LOW and
FLSHCNT_HIGH registers (see Table 116 and Table 117)
provide a running count of flash write cycles. The flash updates
every time GLOB_CMD[6], GLOB_CMD[3], or GLOB_CMD[0]
is set to 1.
Table 116. FLSHCNT_LOW (Page 2, Base Address = 0x7C)
Bits Description
[15:0] Binary counter; number of flash updates, lower word
Table 117. FLSHCNT_HIGH (Page 2, Base Address = 0x7E)
Bits Description
[15:0] Binary counter; number of flash updates, upper word
600
450
300
150
030 40
RETE NTI ON (Y ears)
JUNCTION TEM P E RATURE (°C)
55 70 85 100 125 135 150
11855-023
Figure 25. Flash Memory Retention
Flash Memory Test
Turn to Page 3 (DIN = 0x8003), and then set GLOB_CMD[2] = 1
(DIN = 0x8204, DIN = 0x8300) to run a checksum test of the
internal flash memory, which compares a factory programmed
value with the current sum of the same memory locations. The
result of this test loads into SYS_E_FLAG[6]. Turn to Page 0
(DIN = 0x8000) and use DIN = 0x0800 to read SYS_E_FLAG.
GENERAL-PURPOSE INPUT/OUTPUT
There are four general-purpose input/output pins: DIO1, DIO2,
DIO3, and DIO4. The FNCTIO_CTRL register controls the basic
function of each input/output pin, which provides a number of
useful functions. Each input/output pin only supports one function
at a time. In cases where a single pin has two different assignments,
the enable bit for the lower priority function automatically resets to
zero and is disabled. The priority is (1) data ready, (2) sync clock
input, (3) alarm indicator, and (4) general purpose, where 1
identifies the highest priority and 4 indicates the lowest priority.
Rev. C | Page 30 of 35
Data Sheet ADIS16488A
Table 118. FNCTIO_CTRL (Page 3, Base Address = 0x06)
Bits Description (Default = 0x000D)
[15:12] Not used
11 Alarm indicator: 1 = enabled, 0 = disabled
10 Alarm indicator polarity: 1 = positive, 0 = negative
[9:8] Alarm indicator line selection:
00 = DIO1, 01 = DIO2, 10 = DIO3, 11 = DIO4
7 Sync clock input enable: 1 = enabled, 0 = disabled
6 Sync clock input polarity:
1 = rising edge, 0 = falling edge
[5:4] Sync clock input line selection:
00 = DIO1, 01 = DIO2, 10 = DIO3, 11 = DIO4
3 Data-ready enable: 1 = enabled, 0 = disabled
2 Data ready polarity: 1 = positive, 0 = negative
[1:0] Data ready line selection:
00 = DIO1, 01 = DIO2, 10 = DIO3, 11 = DIO4
Data-Ready Indicator
FNCTIO_CTRL[3:0] provide some configuration options for
using one of the DIOx lines as a data ready indicator signal,
which can drive the interrupt control line of a processor. The
factory default assigns DIO2 as a positive polarity, data ready
signal. Use the following sequence to change this assignment to
DIO1 with a negative polarity: turn to Page 3 (DIN = 0x8003)
and set FNCTIO_CTRL[3:0] = 1000 (DIN = 0x8608, then DIN =
0x8700). The timing jitter on the data ready signal is ±1.4 µs.
Input Sync/Clock Control
FNCTIO_CTRL[7:4] provide some configuration options for
using one of the DIOx lines as an input synchronization signal
for sampling inertial sensor data. For example, use the following
sequence to establish DIO4 as a positive polarity, input clock pin
and keep the factory default setting for the data ready function:
turn to Page 3 (DIN = 0x8003) and set FNCTIO_CTRL[7:0] =
0xFD (DIN = 0x86FD, then DIN = 0x8700). Note that this
command also disables the internal sampling clock, and no
data sampling occurs without the input clock signal. When
selecting a clock input frequency, consider the 330 Hz sensor
bandwidth because undersampling the sensors can degrade
noise and stability performance.
General-Purpose Input/Output Control
When FNCTIO_CTRL does not configure a DIOx pin,
GPIO_CTRL provides register controls for general-purpose use
of the pin. GPIO_CTRL[3:0] provides input/output assignment
controls for each line. When the DIOx lines are inputs, monitor
their level by reading GPIO_CTRL[7:4]. When the DIOx lines
are used as outputs, set their level by writing to GPIO_CTRL[7:4].
For example, use the following sequence to set DIO1 and
DIO3 as high and low output lines, respectively, and set DIO2
and DIO4 as input lines. Turn to Page 3 (DIN = 0x8003) and set
GPIO_CTRL[7:0] = 0x15 (DIN = 0x8815, then DIN = 0x8900).
Table 119. GPIO_CTRL (Page 3, Base Address = 0x08)
Bits Description (Default = 0x00X0)1
[15:8] Don’t care
7 General-Purpose input/output Line 4 (DIO4) data level
6 General-Purpose input/output Line 3 (DIO3) data level
5 General-Purpose input/output Line 2 (DIO2) data level
4 General-Purpose input/output Line 1 (DIO1) data level
3 General-Purpose input/output Line 4 (DIO4) direction
control (1 = output, 0 = input)
2 General-Purpose input/output Line 3 (DIO3) direction
control (1 = output, 0 = input)
1 General-Purpose input/output Line 2 (DIO2) direction
control (1 = output, 0 = input)
0 General-Purpose input/output Line 1 (DIO1) direction
control (1 = output, 0 = input)
1 The GPIO_CTRL[7:4] bits reflect the logic levels on the DIOx lines and do not
have a default setting.
POWER MANAGEMENT
The SLP_CNT register (see Table 120) provides controls for
both power-down mode and sleep modes. The trade-off between
power-down mode and sleep mode is between idle power and
recovery time. Power-down mode offers the best idle power
consumption but requires the most time to recover. In addition,
all volatile settings are lost during power-down but are preserved
during sleep mode.
For timed sleep mode, turn to Page 3 (DIN = 0x8003), write the
amount of sleep time to SLP_CNT[7:0] and then, set SLP_CNT[8]
= 1 (DIN = 0x9101) to start the sleep period.
For a timed power-down period, change the last command to set
SLP_CNT[9] = 1 (DIN = 0x9102).
To p ower down or sleep for an indefinite period, set
SLP_CNT[7:0] = 0x00 first, then set either SLP_CNT[8] or
SLP_CNT[9] to 1. Note that the command takes effect when the
CS line goes high.
To awaken the device from sleep or power-down mode, use one of
the following options to restore normal operation:
• Assert CS from high to low.
• Pulse RST low, then high again.
• Cycle the power.
For example, set SLP_CNT[7:0] = 0x64 (DIN = 0x9064), then
set SLP_CNT[8] = 1 (DIN = 0x9101) to start a sleep period of
100 seconds. If the sleep mode and power-down mode bits are
both set high, the normal sleep mode bit (SLP_CNT[8]) takes
precedence.
Table 120. SLP_CNT (Page 3, Base Address = 0x10)
Bits Description
[15:10] Not used
9 Power-down mode
8 Normal sleep mode
[7:0] Programmable time bits; 1 sec/LSB; 0x00 = indefinite
Rev. C | Page 31 of 35
ADIS16488A Data Sheet
General-Purpose Registers
The USER_SCR_x registers (see Table 121, Tabl e 122, Table 123,
and Table 124) provide four 16-bit registers for storing data.
Table 121. USER_SCR_1 (Page 2, Base Address = 0x74)
Bits Description
[15:0]
User defined
Table 122. USER_SCR_2 (Page 2, Base Address = 0x76)
Bits Description
[15:0] User defined
Table 123. USER_SCR_3 (Page 2, Base Address = 0x78)
Bits Description
[15:0] User defined
Table 124. USER_SCR_4 (Page 2, Base Address = 0x7A)
Bits Description
[15:0] User defined
Real-Time Clock Configuration/Data
The VDDRTC power supply pin (see Table 6, Pin 23) provides
a separate supply for the real-time clock (RTC) function. This
enables the RTC to keep track of time, even when the main supply
(VDD) is off.
Configure the RTC function by selecting one of two modes in
CONFIG[0] (see Table 75). The real-time clock data is available
in the TIME_MS_OUT register (see Table 125), TIME_DH_OUT
register (see Table 126), and TIME_YM_OUT register (see
Table 127). When using the elapsed timer mode, the time data
registers start at 0x0000 when the device starts up (or resets)
and begin keeping time in a manner that is similar to a stop-
watch.
When using the clock/calendar mode, write the current time to
the real-time registers in the following sequence: seconds (TIME_
MS_OUT[5:0]), minutes (TIME_ MS_OUT[13:8]), hours
(TIME_DH_OUT[5:0]), day (TIME_DH_OUT[12:8]), month
(TIME_YM_OUT[3:0]), and year (TIME_YM_OUT[14:8]). The
updates to the timer only become active after a write is completed
correctly to the TIME_YM_OUT[14:8] byte.
The real-time clock registers reflect the newly updated
values only after the next seconds tick of the clock that
follows the write to TIME_YM_OUT[14:8] (year). Writing to
TIME_YM_OUT[14:8] activates all timing values; therefore,
always write to this location last when updating the timer, even
if the year information does not require updating.
Write the current time to each time data register after setting
CONFIG[0] = 1 (DIN = 0x8003, DIN = 0x8A01). Note that
CONFIG[1] provides a bit for managing daylight savings time.
After the CONFIG and TIME_xx_OUT registers are configured,
set GLOB_CMD[3] = 1 (DIN = 0x8003, DIN = 0x8204, DIN =
0x8300) to back up these settings in flash, and use a separate
3.3 V source to supply power to the VDDRTC function. Note
that access to time data in the TIME_xx_OUT registers requires
normal operation (VDD = 3.3 V and full startup), but the timer
function only requires that VDDRTC = 3.3 V when the remainder
of the ADIS16488A is turned off.
Table 125. TIME_MS_OUT (Page 0, Base Address = 0x78)
Bits Description
[15:14] Not used
[13:8] Minutes, binary data, range = 0 to 59
[7:6] Not used
[5:0] Seconds, binary data, range = 0 to 59
Table 126. TIME_DH_OUT (Page 0, Base Address = 0x7A)
Bits Description
[15:13] Not used
[12:8] Day, binary data, range = 1 to 31
[7:6] Not used
[5:0] Hours, binary data, range = 0 to 23
Table 127. TIME_YM_OUT (Page 0, Base Address = 0x7C)
Bits Description
[15] Not used
[14:8] Year, binary data, range = 0 to 99, relative to 2000 A.D.
[7:4] Not used
[3:0] Month, binary data, range = 1 to 12
Rev. C | Page 32 of 35
Data Sheet ADIS16488A
APPLICATIONS INFORMATION
MOUNTING BEST PRACTICES
Figure 26. Mounting Example
For best performance, follow these simple rules when installing
the ADIS16488A into a system:
1. Eliminate opportunity for translational force (x- and y-axis
direction, per Figure 6) application on the electrical connector.
2. Isolate mounting force to the four corners, on the portion
of the package surface that surrounds the mounting holes.
3. Use uniform mounting forces on all four corners. The
suggested torque setting is 40 inch-ounces (0.285 N-m).
These three rules help prevent irregular force profiles, which
can warp the package and introduce bias errors in the sensors.
Figure 26 provides an example that leverages washers to set the
package off the mounting surface and uses 2.85 mm pass-through
holes and backside washers/nuts for attachment. Figure 27 and
Figure 28 provide some details for mounting hole and connector
alignment pin drill locations.
For more information on mounting the ADIS16488A, see the
AN-1295 Application Note.
Figure 27. Suggested PCB Layout Pattern, Connector Down
Rev. C | Page 33 of 35
ADIS16488A Data Sheet
Rev. C | Page 34 of 35
0.4334 [11.0]
0.0240 [0.610]
0.019685
[0.5000]
(TYP)
0.054 [1.37]
0.0394 [1.00]
0.0394 [1.00] 0.1800
[4.57]
NONPLATED
THRU HOLE 2×
0.022± DIA (TYP)
0.022 DIA THRU HOLE (TYP)
NONPLATED THRU HOLE
11855-026
Figure 28. Suggested Layout and Mechanical Design When Using Samtec
P/N CLM-112-02-G-D-A for the Mating Connector
EVALUATION TOOLS
Breakout Board, ADIS16IMU1/PCBZ
The ADIS16IMU1/PCBZ (sold separately) provides a breakout
board function for the ADIS16488A, which means that it provides
access to the ADIS16488A through larger connectors that support
standard 1 mm ribbon cabling. It also provides four mounting
holes for attachment of the ADIS16488A to the breakout board.
PC-Based Evaluation, EVAL-ADIS
The EVAL-ADIS provides the system support PC-based evaluation
of the ADIS16488A.
POWER SUPPLY CONSIDERATIONS
The ADIS16488A has approximately 24 μF of capacitance across
the VDD and GND pins. Whereas this capacitor bank provides a
large amount of localized filtering, it also presents an opportunity
for excessive charging current when the VDD voltage ramps too
quickly. Use the following relationship to help determine the
appropriate VDD voltage profile, with respect to any current-limit
functions that can cause the power supply to lose regulation and
potentially introduce unsafe conditions for the ADIS16488A.

d
t
dV
Cti
In addition to managing the initial voltage ramp, take note of the
transient current demand that the ADIS16488A requires during its
start-up/self initialization process. When VDD reaches 2.85 V, the
ADIS16488A begins its start-up process. Figure 29 offers a broad
perspective that shows when to expect the spikes in current,
whereas Figure 30 provides more detail on the current/time
behavior during the peak transient condition, which typically
occurs approximately 350 ms after VDD reaches 2.85 V.
11855-129
CH1 2.00V
CH4 100mA Ω1M POINTS
1.00ms 1.00MS/s CH1 2.72V
T 9.800%
1
4
T
VDD
CURRENT
Figure 29. Transient Current Demand, Start Up
11855-128
CH4 100mA Ω1M POINTS
1.00ms 1.00MS/s CH1 2.72V
T 9.800%
4
T
CURRENT
Figure 30. Transient Current Demand, Peak Demand
Data Sheet ADIS16488A
Rev. C | Page 35 of 35
OUTLINE DIMENSIONS
12-07-2012-E
BOTTOM VIEW
FRONT VIEW
44.254
44.000
43.746
42.854
42.600
42.346
1.942
1.642
1.342
47.254
47.000
46.746
14.254
14.000
13.746
39.854
39.600
39.346 20.10
19.80
19.50
Ø 2.40 BSC
(4 PLACES)
15.00
BSC
8.25
BSC
2.20 BSC
(8 PLACES)
DETAIL A
PIN 1
DETAIL B
5.50
BSC
5.50
BSC
1.00 BSC
2.84 BSC
6.50 BSC
DETAIL A
DETAIL B
1.00 BSC
PITCH 0.30 SQ BSC
3.454
3.200
2.946
Figure 31. 24-Lead Module with Connector Interface [MODULE]
(ML-24-6)
Dimensions shown in millimeters
ORDERING GUIDE
Model1 Temperature Range Package Description Package Option
ADIS16488BMLZ −40°C to +105°C 24-Lead Module with Connector Interface [MODULE] ML-24-6
ADIS16488CMLZ −55°C to +105°C 24-Lead Module with Connector Interface [MODULE] ML-24-6
1 Z = RoHS Compliant Part.
©2014–2015 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D11855-0-8/15(C)
Mouser Electronics
Authorized Distributor
Click to View Pricing, Inventory, Delivery & Lifecycle Information:
Analog Devices Inc.:
ADIS16488BMLZ ADIS16488CMLZ