FMT1000-series
Motion Tracking Module with Output of Orientation,
Inertial Motion Data and Magnetic Field
Features
Description
Complete module providing many user-configurable
outputs
Incorporates Fairchild‟s highly accurate Inertial
Measurement Unit FIS1100
The FMT1000-series is a product group of turn-key
industrial grade Motion Tracker modules intended for
integration of motion intelligence on unmanned systems,
heavy industry, machine automation and agriculture.
Roll/Pitch Accuracy (Dynamic): 3.0 deg
Industry-leading signal processing pipeline
TM
(AttitudeEngine ) with vibration-rejection
Short time to market with turn-key solution
Heading Accuracy: 3.0 deg
Minimal requirements on host processor
No knowledge of inertial sensors signal processing
required for best performance
®
Drivers and examples on ARM mbed
TM
Low Power (45 mW at 3.0 V)
PLCC28-compatible PCB (12.1 x 12.1 x 2.6 mm)
Applications
Light Industrial and Robotics
VR/AR
GNSS Augmentation and Dead Reckoning
The high data rates of up to 1 kHz and orientation
accuracy of 3.0º RMS makes it an excellent choice for
applications in control and stabilization, and navigation
e.g. unmanned vehicles.
Calibration and testing has already been performed on
each individual unit ensuring high quality of the product
delivered and its performance.
The FMT1000-series has three products (see below)
with distinctive capabilities and outputs.
Product
Output
FMT1010
IMU
FMT1020
VRU
FMT1030
AHRS
Motion Data
●
●
●
Magnetic Field
●
●
●
Agriculture and Heavy Machinery
Miniature Aerial Vehicles (Drones)
Image Stabilization and Platform Stabilization
Roll/Pitch
●
●
Pedestrian Dead-Reckoning
Heading
Tracking
●
●
Related Resources
With output of 3D orientation, 3D rate of turn, 3D
accelerations, and 3D magnetic field directly from the
module, the FMT1000-series can be integrated with
minimal hardware and software development. The
output is configurable in terms of data selection, output
format, output data rate and communication protocol,
reducing the load on the host processor.
Referenced Yaw
●
FMT1000 Product Folder
FEBFMT1030 User Guide
FCS MT Manager User Guide
FCS MFM User Guide
Figure 1.
© 2015 Fairchild Semiconductor Corporation
FMT1000-series • Rev. 1.0
FMT1000-series Module
www.fairchildsemi.com
FMT1000-series — Motion Tracking Module With Output of Orientation, Inertial Motion Data and Magnetic Field
November 2015
1
General Information............................................................................................................. 3
1.1
1.2
1.3
1.4
1.5
1.6
1.7
ORDERING INFORMATION ............................................................................................................................... 3
BLOCK DIAGRAM .......................................................................................................................................... 3
TYPICAL APPLICATION ................................................................................................................................... 4
PIN CONFIGURATION ..................................................................................................................................... 4
PIN MAP ...................................................................................................................................................... 5
PIN DESCRIPTIONS ....................................................................................................................................... 6
PERIPHERAL INTERFACE SELECTION ............................................................................................................... 7
1.7.1
Peripheral Interface Architecture ...................................................................................................... 7
1.7.2
Xbus Protocol ................................................................................................................................... 8
1.7.3
MTSSP Synchronous Serial Protocol ............................................................................................... 8
2
1.7.4
I C .................................................................................................................................................. 11
1.7.5
SPI ................................................................................................................................................. 12
1.7.6
UART Half Duplex .......................................................................................................................... 13
1.7.7
UART Full Duplex with RTS/CTS Flow Control .............................................................................. 13
1.8 RECOMMENDED EXTERNAL COMPONENTS .................................................................................................... 14
2
FMT1000-Series Architecture ............................................................................................ 15
2.1
FMT1000-SERIES CONFIGURATIONS ........................................................................................................... 15
2.1.1
FMT1010 IMU ................................................................................................................................ 15
2.1.2
FMT1020 VRU ............................................................................................................................... 15
2.1.3
FMT1030 AHRS ............................................................................................................................. 15
2.2 SIGNAL PROCESSING PIPELINE .................................................................................................................... 15
2.2.1
Strap-down Integration ................................................................................................................... 15
TM
2.2.2
XKF3 Sensor Fusion Algorithm ................................................................................................... 15
2.2.3
Frames of reference used in FMT1000-Series ............................................................................... 16
3
3D Orientation and Performance Specifications ................................................................ 17
3.1
3.2
4
3D ORIENTATION SPECIFICATIONS ............................................................................................................... 17
SENSORS SPECIFICATIONS .......................................................................................................................... 17
Sensor Calibration ............................................................................................................. 19
5
System and Electrical Specifications ................................................................................. 19
5.1
5.2
5.3
5.4
5.5
6
INTERFACE SPECIFICATIONS ........................................................................................................................ 19
SYSTEM SPECIFICATIONS ............................................................................................................................ 19
ELECTRICAL SPECIFICATIONS....................................................................................................................... 20
ABSOLUTE MAXIMUM RATINGS ..................................................................................................................... 20
COMPLIANCE .............................................................................................................................................. 20
FMT1000-Series Settings and Outputs.............................................................................. 21
6.1
6.2
6.3
6.4
7
MESSAGE STRUCTURE ................................................................................................................................ 21
OUTPUT SETTINGS ..................................................................................................................................... 22
MTDATA2.................................................................................................................................................. 23
SYNCHRONIZATION AND TIMING .................................................................................................................... 24
Magnetic Interference........................................................................................................ 25
7.1
7.2
8
MAGNETIC FIELD MAPPING .......................................................................................................................... 25
ACTIVE HEADING STABILIZATION (AHS) ........................................................................................................ 25
Package and Handling ...................................................................................................... 26
8.1
8.2
8.3
8.4
PACKAGE DRAWING .................................................................................................................................... 26
MOUNTING CONSIDERATIONS....................................................................................................................... 27
PACKAGING ................................................................................................................................................ 28
REFLOW SPECIFICATION .............................................................................................................................. 28
© 2015 Fairchild Semiconductor Corporation
FMT1000-series • Rev. 1.0
www.fairchildsemi.com
2
FMT1000-series — Motion Tracking Module With Output of Orientation, Inertial Motion Data and Magnetic Field
Table of Contents
1.1
Ordering Information
Part Number
Output
Package
Packing
Method
FMT1010T
IMU; inertial data
FMT28_028, JEDEC-PLCC-28 Compatible
Tray of 20
FMT1020T
VRU; inertial data, roll/pitch
(referenced), yaw (unreferenced)
FMT28_028, JEDEC-PLCC-28 Compatible
Tray of 20
FMT1030T
AHRS; inertial data, roll/pitch/yaw
FMT28_028, JEDEC-PLCC-28 Compatible
Tray of 20
FMT1010R
IMU; inertial data
FMT28_028, JEDEC-PLCC-28 Compatible
Reel of 250
FMT1020R
VRU; inertial data, roll/pitch
(referenced), yaw (unreferenced)
FMT28_028, JEDEC-PLCC-28 Compatible
Reel of 250
FMT1030R
AHRS; inertial data, roll/pitch/yaw
FMT28_028, JEDEC-PLCC-28 Compatible
Reel of 250
Note:
1. Other packaging methods available on request. Contact Fairchild for more information.
1.2
Block Diagram
Figure 2.
© 2015 Fairchild Semiconductor Corporation
FMT1000-series • Rev. 1.0
FMT1000-Series Module Block Diagram
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3
FMT1000-series — Motion Tracking Module With Output of Orientation, Inertial Motion Data and Magnetic Field
1 General Information
Typical Application
Figure 3.
1.4
FMT1000-series — Motion Tracking Module With Output of Orientation, Inertial Motion Data and Magnetic Field
1.3
Typical Application
Pin Configuration
Figure 4.
© 2015 Fairchild Semiconductor Corporation
FMT1000-series • Rev. 1.0
Pin Assignment
www.fairchildsemi.com
4
Pin Map
The pin map depends on the peripheral selection. See section 1.7 on how to set the peripherals.
Pin #
PSEL: I C
PSEL: SPI
PSEL:
UART Half Duplex
PSEL:
UART Full Duplex
1
DNC
DNC
DNC
DNC
2
DNC
DNC
DNC
DNC
2
3
DNC
DNC
DNC
DNC
4
GND
GND
GND
GND
5
VDD
VDD
VDD
VDD
6
nRST
nRST
nRST
nRST
7
VDDIO
VDDIO
VDDIO
VDDIO
8
GND
GND
GND
GND
9
DNC
SPI_NCS
DNC
DNC
10
ADD2
(2)
SPI_MOSI
DNC
DNC
11
ADD1
SPI_MISO
DNC
DNC
12
ADD0
SPI_SCK
DNC
DNC
13
GND
GND
GND
GND
14
PSEL0
PSEL0
PSEL0
PSEL0
15
PSEL1
PSEL1
PSEL1
PSEL1
16
SYNC_IN
SYNC_IN
SYNC_IN
SYNC_IN
17
DNC
DNC
DNC
DNC
18
DNC
DNC
DNC
DNC
19
DNC
DNC
DNC
DNC
20
DNC
DNC
DNC
DNC
21
DNC
DNC
DE
22
DRDY
DRDY
nRE
RTS
23
I2C_SDA
DNC
UART_RX
UART_RX
24
I2C_SCL
DNC
UART_TX
UART_TX
25
GND
GND
GND
GND
26
DNC
DNC
DNC
DNC
27
DNC
DNC
DNC
DNC
28
DNC
DNC
DNC
DNC
(3)
CTS
Notes:
2
2. I C addresses, see Table 3: List of I2C Addresses
3. CTS cannot be left unconnected if the interface is set to UART full duplex. If HW flow control is not used, connect
to GND.
S
© 2015 Fairchild Semiconductor Corporation
FMT1000-series • Rev. 1.0
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5
FMT1000-series — Motion Tracking Module With Output of Orientation, Inertial Motion Data and Magnetic Field
1.5
Pin Descriptions
Name
Type
Description
Power Interface
VDD
Power
Power supply voltage for sensing elements.
VDDIO
Power
Digital I/O supply voltage.
Controls
PSEL0
PSEL1
These pins determine the signal interface. See table below. Note that when the
Selection Pins PSEL0/PSEL1 is not connected, its value is 1. When PSEL0/PSEL1 is connected
to GND, its value is 0.
Active low reset pin. Only drive with an open drain output or momentary (tactile)
switch to GND. During normal operation this pin must be left floating, because this
line is also used for internal resets. This pin has a weak pull-up to VDDIO.
nRST
ADD2
ADD1
2
Selection Pins I C address selection lines.
ADD0
Signal Interface
I2C_SDA
I2C_SCL
2
2
I C Interface
SPI_nCS
SPI_MOSI
SPI_MISO
I C serial data.
2
I C serial clock.
SPI chip select (active low).
SPI Interface
SPI_SCK
SPI serial data input (slave).
SPI serial data output (slave).
SPI serial clock.
RTS
Hardware flow control in UART full duplex mode (Ready-to-Send).
CTS
Hardware flow control in UART full duplex mode (Clear-to-Send).
nRE
DE
UART
Interface
Receiver control signal in UART half duplex mode.
Transmitter control signal in UART half duplex mode.
UART_RX
Receiver data input.
UART_TX
Transmitter data output.
SYNC_IN
DRDY
Sync Interface SYNC_IN accepts a trigger which sends out the latest available data message
Data Ready
© 2015 Fairchild Semiconductor Corporation
FMT1000-series • Rev. 1.0
2
Data ready pin indicates that data is available (SPI / I C).
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FMT1000-series — Motion Tracking Module With Output of Orientation, Inertial Motion Data and Magnetic Field
1.6
Peripheral Interface Selection
1.7.1
The FMT1000-series modules are designed to be used
as a peripheral device in embedded systems. The
module
supports
Universal
Asynchronous
Receiver/Transmitter (UART), inter-integrated circuit
2
(I C) and the Serial Peripheral Interface (SPI) protocols.
2
The I C and SPI protocols are well suited for
communications between integrated circuits with onboard peripherals. The FMT1000-series modules have
four modes of peripheral interfacing. Only one mode can
be used at a time and is determined by the state of
peripheral selection pins PSEL0 and PSEL1 at startup.
Table 1 specifies how the PSEL lines select the
peripheral interface. Note that the module has internal
pull-ups. Not connecting PSEL results in a value of 1,
connecting PSEL to a GND results in a value of 0.
Examples for communication on embedded systems are
available at https://developer.mbed.org/teams/FairchildSemiconductor
Table 1.
Peripheral Interface Architecture
At its core the module uses the proprietary Xbus
protocol. This protocol is available on all interfaces,
2
UART (asynchronous serial port interfaces) and I C and
2
SPI buses. The I C and SPI buses differ from UART in
that they are synchronous and have a master-slave
relation in which the slave cannot send data by itself.
This makes the Xbus protocol not directly transferable to
these buses. For this the MTSSP protocol is introduced
that provides a way to exchange standard Xbus protocol
2
messages over the I C and SPI buses.
Figure 5 shows how MTSSP is fitted in the module's
(simplified) communication architecture. The module
has generic Input- and Output-Queues for Xbus protocol
2
messages. For I C and SPI these messages are
translated by the MTSSP layer. For the UART
connection these messages are transported as-is.
Peripheral Interface Selection
Interface
PSEL0
PSEL1
IC
1
1
2
SPI
0
1
UART Half-Duplex
1
0
UART Full-Duplex
0
0
Figure 5.
© 2015 Fairchild Semiconductor Corporation
FMT1000-series • Rev. 1.0
FMT Module Architecture
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7
FMT1000-series — Motion Tracking Module With Output of Orientation, Inertial Motion Data and Magnetic Field
1.7
Communication is always initiated and driven by the
Master; the Master either writes data to the module or
the Master reads data from the module. The Master
sends messages to the module in order to control it.
These messages are reduced Xbus messages. A
reduced Xbus message is equal to a normal Xbus
message with the exception that preamble and BusID
are removed to save bandwidth. The calculation of the
checksum is done by assuming a BusID value of 0xFF
(master device).
Xbus Protocol
The Xbus protocol is a proprietary protocol that allows
straightforward interfacing with the FMT1000-series.
Information about the Xbus protocol can be found in the
Low-Level Communication Protocol Documentation.
Section 6 provides a short introduction on the Xbus
protocol. It is advised to go read this short introduction
first before proceeding to the MTSSP explanation.
1.7.3
MTSSP Synchronous Serial Protocol
2
The communication protocol used for both I C and SPI
is called MTSSP (MT Synchronous Serial Protocol).
The module needs time to process the control
messages it receives and will generate an acknowledge
message when ready. In order to get these
acknowledge messages at the Master the Master needs
to read them.
Data Flow
MTSSP communication happens according the masterslave model. The FMT1000-series module will always
fulfill the slave-role while the user/integrator of the
module is always the Master.
Figure 6.
The following diagram shows data flow between Master
and module:
Data Flows within MTSSP
Data Ready Signal
again. The Master can change the behavior of the
DRDY signal.
The Data Ready Signal (DRDY) is a notification line
driven by the module. Its default behavior is to indicate
the availability of new data in either the notification- or
the measurement pipe. By default, the line is idle low
and will go high when either pipe contains an item.
When both pipes are empty the DRDY line will go low
The polarity can be changed to idle high, the output type
can be switched between push-pull and open drain. The
state of a specific pipe can be ignored. For example, it
can be configured that the presence of data in the
notification pipe won't influence the state of the DRDY
pin.
Opcodes
The following opcodes are defined.
Table 2.
2
Opcodes for SPI and I C
Opcode
Name
Read/Write
0x01
ProtocolInfo
Read
Status of the protocol behaviour, protocol version
0x02
ConfigureProtocol
Write
Tweak the Protocol, e.g. the behaviour of the DRDY pin,
behaviour of the pipes
0x03
ControlPipe
Write
Used to send control messages to the module
0x04
PipeStatus
Read
Provides status information for the read pipes
0x05
NotificationPipe
Read
Used to read non-measurement data: errors acknowledgements
and other notifications from the module
0x06
MeasurementPipe
Read
All measurement data generated by the module will be available
in the measurement pipe
© 2015 Fairchild Semiconductor Corporation
FMT1000-series • Rev. 1.0
Description
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8
FMT1000-series — Motion Tracking Module With Output of Orientation, Inertial Motion Data and Magnetic Field
1.7.2
The ProtocolInfo opcode allows the Master to read the active protocol configuration. The format of the message is as
follows (All data is little endian, byte aligned):
struct MtsspInfo
{
uint8_t m_version;
uint8_t m_drdyConfig;
};
m_version
7
6
5
4
3
2
1
0
VERSION [7:0]
m_drdyConfig
Bits 7:4
Reserved for future use
Bit 3
MEVENT: Measurement pipe DRDY event enable
0: Generation of DRDY event is disabled
1: Generation of DRDY event is enabled
Bit 2
NEVENT: Notification pipe DRDY event enable
0: Generation of DRDY event is disabled
1: Generation of DRDY event is enabled
Bit 1
OTYPE: Output type of DRDY pin
0: Push/pull
1: Open drain
Bit 0
POL: Polarity of DRDY signal
0: Idle low
1: Idle high
ConfigureProtocol (0x02)
The ProtocolInfo opcode allows the Master to change the active protocol configuration. The format of the message is
as follows (All data is little endian, byte aligned):
struct MtsspConfiguration
{
uint8_t m_drdyConfig;
};
m_drdyConfig
Bits 7:4
Reserved for future use
Bit 3
MEVENT: Measurement pipe DRDY event enable
0: Generation of DRDY event is disabled
1: Generation of DRDY event is enabled
Bit 2
NEVENT: Notification pipe DRDY event enable
0: Generation of DRDY event is disabled
1: Generation of DRDY event is enabled
Bit 1
OTYPE: Output type of DRDY pin
0: Push/pull
1: Open drain
Bit 0
POL: Polarity of DRDY signal
0: Idle high
1: Idle low
© 2015 Fairchild Semiconductor Corporation
FMT1000-series • Rev. 1.0
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9
FMT1000-series — Motion Tracking Module With Output of Orientation, Inertial Motion Data and Magnetic Field
ProtocolInfo (0x01)
The ControlPipe opcode allows the Master to write messages to the control pipe. The bytes following the opcode are
interpreted as a single (reduced) Xbus message
PipeStatus (0x04)
The PipeStatus opcode allows the Master to retrieve the status of the module's Notification- and Measurement pipes.
The format of the message is as follows (All data is little endian, byte aligned):
struct MtsspConfiguration
{
uint16_t m_notificationMessageSize;
uint16_t m_measurementMessageSize;
};
NotificationPipe (0x05)
The NotificationPipe opcode is used to read from the notification pipe. The read data is a single reduced Xbus
message
MeasurementPipe (0x06)
The MeasurementPipe opcode is used to read from the measurement pipe. The read data is a single reduced Xbus
message
© 2015 Fairchild Semiconductor Corporation
FMT1000-series • Rev. 1.0
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10
FMT1000-series — Motion Tracking Module With Output of Orientation, Inertial Motion Data and Magnetic Field
ControlPipe (0x03)
2
IC
2
2
The FMT1000-series supports the I C transport layer. The FMT1000-series module acts as an I C Slave. The Master
is defined as the user of the FMT1000-series module.
2
The I C slave address is determined by the ADD0, ADD1 and ADD2 pins. These pins are pulled-up internally so
when left unconnected the address selection defaults to ADD[0..2] = 111.
Table 3.
2
List of I C Addresses
2
Table 4.
I C Address
ADD0
ADD1
ADD2
0x1D
0
0
0
0x1E
1
0
0
0x28
0
1
0
0x29
1
1
0
0x68
0
0
1
0x69
1
0
1
0x6A
0
1
1
0x6B (default)
1
1
1
2
Implemented I C Bus Protocol Features
Feature
Slave Requirement
FMT1000-Series
7-Bit Slave Address
Mandatory
Yes
10-Bit Slave Address
Optional
No
Mandatory
Yes
N/A
N/A
Acknowledge
Arbitration
(4)
Clock Stretching
Optional
Yes
Device ID
Optional
No
General Call Address
Optional
No
Software Reset
Optional
No
N/A
N/A
START Condition
Mandatory
Yes
STOP Condition
Mandatory
Yes
Synchronization
N/A
N/A
START byte
Note:
2
4. The FMT1000-series module relies on the I C clock stretching feature to overcome fluctuations in processing
time, the Master is required to support this feature
Reading from the module
Reading from the module should start by first writing an opcode that tells the module what the Master needs to read.
2
Based on the opcode the module will prepare the related data to be transmitted. The Master then can do an I C read
transfer to retrieve the data. Starting the read transfer after the opcode write can also be done using a repeated start
condition as is shown in Figure 7.
It is up to the Master to determine how many bytes need to be read. The Master should use the PipeStatus (0x04)
opcode of the MTSSP protocol for this.
If the master reads more bytes than necessary the FMT1000-series will restart sending the requested data from the
beginning.
The following diagram shows a read message transfer using a repeated start:
Figure 7.
© 2015 Fairchild Semiconductor Corporation
FMT1000-series • Rev. 1.0
2
Read Message Transfer using a Repeated Start (I C)
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11
FMT1000-series — Motion Tracking Module With Output of Orientation, Inertial Motion Data and Magnetic Field
1.7.4
Figure 8.
1.7.5
2
Full Write Transfer and Full Read Transfer (I C)
The module uses SPI mode 3; Data is captured on the
rising clock edge and data is latched/propagated on the
falling clock edge. (CPOL=1 and CPHA=1);
SPI
The FMT1000-series supports the SPI transport layer.
The FMT1000-series module acts as an SPI Slave. The
Master is defined as the user of the FMT1000-series
module.
Data is clocked-out MSB first. The module uses an 8-bit
data format
SPI Configuration
Data Transfer
The FMT1000-series supports 4-wire mode SPI. The
four lines used are:
There is a single type of SPI transfer used for all
communications. The diagram below shows the basic
transfer.
Chipselect (SPI_nCS)
Serial Clock (SPI_SCK)
Master data in, slave data out (SPI_MISO)
Master data out, slave data in (SPI_MOSI)
Figure 9.
SPI Basic Transfer
A transfer is started selecting the Slave by pulling the
SPI_nCS low. The SPI_nCS line is to be kept low for the
duration of the transfer. The Slave will interpret the
rising edge of the SPI_nCS line as the end of the
transfer.
The second- to fourth byte transmitted are the fill words.
These fill words are needed to give the Slave some time
to prepare the remainder of the transfer. In principal, the
Slave is free to choose the value of the fill word; and its
value should therefore be ignored by the Master.
However, the first 4 bytes transmitted by the FMT1000series module are always 0xFA, 0xFF, 0xFF, 0xFF.
The Master places the data it needs to transmit on the
SPI_MOSI line. The Slave will place its data on the
SPI_MISO line.
Following the first four words are the actual data of the
transfer. It is the responsibility of the Master to
determine how many bytes need to be transferred. The
Master should use the PipeStatus (0x04) opcode of the
MTSSP protocol for this.
The first byte transmitted by the Master is the opcode
which identifies what kind of data is transmitted by the
Master and what kind of data the Master wants to read
from the Slave (See MTSSP).
Timing
The following timing constraints apply to the SPI transport layer.
Figure 10.
© 2015 Fairchild Semiconductor Corporation
FMT1000-series • Rev. 1.0
SPI Timing
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12
FMT1000-series — Motion Tracking Module With Output of Orientation, Inertial Motion Data and Magnetic Field
The following diagram shows a read message transfer using a full write transfer for the opcode followed by a read
transfer to get the data:
Symbol
Timing Specifications
Parameter
Min. Max. Unit
T1
Slave select to first
complete word delay
4
μs
T2
Byte time
4
μs
T3
Consecutive SPI transfer
guard time
3
μs
Max. SPI bitrate
1.7.6
2
Figure 11.
Note that in this mode the UART of the FMT1000-series
itself is still operating full duplex.
Mbit
1.7.7
The FMT1000-series module can be configured to
communicate over UART in half duplex mode. The
UART frame configuration is 8 data bits, no parity and 1
stop bit (8N1). In addition to the RX and TX pins, the
control lines nRE and DE are used. These control
outputs are used to drive the TX signal on a shared
medium and to drive the signal of the shared medium on
the RX signal.
The CTS signal is an input for the FMT. The FMT
checks the state of the CTS line at the start of every
byte it transmits. If CTS is low the byte will be
transmitted. Otherwise transmission is postponed until
CTS is lowered. When during the transmission of a byte
the CTS signal is raised, then the transmission of that
byte is completed before postponing further output. This
byte will not be retransmitted. This behavior is shown in
the following image:
A typical use case for this mode is to directly drive a
RS485 transceiver where the shared medium is the
RS485 signal and nRE and DE lines control the buffers
inside the transceiver.
When the FMT is transmitting data on its TX pin it will
raise both the nRE and DE lines, else it will pull these
lines low.
Data Transmit Behavior Under CTS
The RTS signal is an output for the FMT. If the RTS line
is high, the FMT is busy and unable to receive new
data. Otherwise the FMT‟s UART is idle and ready to
receive. After receiving a byte the DMA controller of the
Figure 13.
UART Full Duplex with RTS/CTS Flow
Control
The FMT1000-series module can be configured to
communicate over UART in full duplex mode with
RTS/CTS flow control. The UART frame configuration is
8 data bits, no parity and 1 stop bit (8N1). In addition to
the RX and TX signals for data communication the RTS
and CTS signals are used for hardware flow control.
UART Half Duplex
Figure 12.
Behavior of the nRE and DE Lines
FMT will transfer the byte to its receive FIFO. The RTS
signal will be asserted during this transfer. So with every
byte received the RTS line is raised shortly like shown in
the following image:
FRTS Behavior Under Data Reception
This communication mode can be used without hardware flow control. In this case the CTS line needs to be tied low
(GND) to make the FMT transmit.
© 2015 Fairchild Semiconductor Corporation
FMT1000-series • Rev. 1.0
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13
FMT1000-series — Motion Tracking Module With Output of Orientation, Inertial Motion Data and Magnetic Field
Table 5.
Recommended External Components
Description
Component
Typical value
I C Pull-up Resistor
Rpu
2.7 kΩ
2
Notes:
2
5. Rpu is only needed when the FMT1000-series is configured for I C interface.
2
6. RPSEL is only required when interface is not I C.
Figure 14.
© 2015 Fairchild Semiconductor Corporation
FMT1000-series • Rev. 1.0
External Components
2
(I C Interface)
Figure 15.
External Components
(UART Interface)
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14
FMT1000-series — Motion Tracking Module With Output of Orientation, Inertial Motion Data and Magnetic Field
1.8
This section discusses the FMT1000-series architecture
including the various configurations and the signal
processing pipeline.
7.2) the drift in unreferenced yaw can be limited to 1 deg
after 60 minutes, even in magnetically disturbed
environments.
2.1
2.1.3
FMT1000-Series Configurations
The FMT1000-series is fully-tested, self-contained
modules that can 3D output orientation data (Euler
angles (roll, pitch, and yaw), rotation matrix (DCM) and
quaternions), orientation and velocity increments (∆q
and ∆v) and sensors data (acceleration, rate of turn,
magnetic field). The FMT1000-series module is
available as an Inertial Measurement Unit (IMU),
Vertical Reference Unit (VRU) and Attitude and Heading
Reference System (AHRS). Depending on the product,
output options may be limited to sensors data and/or
unreferenced yaw.
2.2
2.2.1
FMT1010 IMU
2.2.2
XKF3
TM
Sensor Fusion Algorithm
XKF3 is a sensor fusion algorithm, based on Extended
Kalman Filter framework that uses 3D inertial sensor
data (orientation and velocity increments) and 3D
magnetometer, also known as „9D‟ to optimally estimate
3D orientation with respect to an Earth fixed frame.
XKF3 takes the orientation and velocity increments
together with the magnetic field updates and fuses this
to produce a stable orientation (roll, pitch and yaw) with
respect to the earth fixed frame.
The XKF3 sensor fusion algorithm can be processed
with filter profiles. These filter profiles contain predefined
filter parameter settings suitable for different user
application scenarios.
FMT1020 VRU
The FMT1020 is a 3D vertical reference unit (VRU). Its
TM
orientation algorithm (XKF3 ) outputs 3D orientation
data with respect to a gravity referenced frame: drift-free
roll, pitch and unreferenced yaw. In addition, it outputs
calibrated sensor data: 3D acceleration, 3D rate of turn
and 3D earth-magnetic field data. All modules of the
FMT1000-series are also capable of outputting data
generated by the strap down integration algorithm (the
AttitudeEngine outputting orientation and velocity
increments ∆q and ∆v). The 3D acceleration is also
available as so-called free acceleration which has
gravity subtracted. Although the yaw is unreferenced,
though still superior to gyroscope integration. With the
feature Active Heading Stabilization (AHS, see section
© 2015 Fairchild Semiconductor Corporation
FMT1000-series • Rev. 1.0
Strap-down Integration
The optimized strap-down algorithm (AttitudeEngine)
performs high-speed dead-reckoning calculations at
1 kHz allowing accurate capture of high frequency
motions. This approach ensures a high bandwidth.
Orientation and velocity increments are calculated with
full coning and sculling compensation. At an output data
rate of up to 100 Hz, no information is lost, yet the
output data rate can be configured low enough for
systems with limited communication bandwidth. These
orientation and velocity increments are suitable for any
3D motion tracking algorithm. Increments are internally
time-synchronized with the magnetometer data.
The FMT1010 module is an Inertial Measurement Unit
(IMU) that outputs 3D rate of turn, 3D acceleration and
3D magnetic field. The FMT1000-series also outputs
coning and sculling compensated orientation increments
and velocity increments (∆q and ∆v) from its
TM
AttitudeEngine . Advantages over a gyroscopeaccelerometer combo-sensor are the inclusion of
synchronized magnetic field data, on-board signal
processing and the easy-to-use communication
protocol. Moreover, the testing and calibration
performed by Fairchild result in a robust and reliable
sensor module, that can be integrated within a short
time frame. The signal processing pipeline and the suite
of output options allow access to the highest possible
accuracy at any bandwidth, limiting the load on the
application processor.
2.1.2
Signal Processing Pipeline
The FMT1000-series is a self-contained module, so all
calculations and processes such as sampling, coning
and sculling compensation and the XKF3 sensor fusion
algorithm run on board.
All FMT1000-series feature the Fairchild FIS1100 (an
accelerometer/gyroscope
combo-sensor),
a
magnetometer, a high-accuracy crystal and a low-power
MCU. The MCU coordinates the synchronization and
timing of the various sensors, it applies calibration
models (e.g. temperature modules) and output settings
and runs the sensor fusion algorithm. The MCU also
generates output messages according to the proprietary
XBus communication protocol. The messages and the
data output are fully configurable, so that the FMT1000series limits the load, and thus power consumption, on
the application processor.
2.1.1
FMT1030 AHRS
The FMT1030 supports all features of the FMT1010 and
FMT1020, and in addition is a full gyro-enhanced
Attitude and Heading Reference System (AHRS). It
outputs drift-free roll, pitch and true/magnetic North
referenced yaw and sensors data: 3D acceleration, 3D
rate of turn, as well as 3D orientation and velocity
increments (∆q and ∆v), and 3D earth-magnetic field
data. Free acceleration is also available for the
FMT1030 AHRS.
The following filter profiles are available:
General – suitable for most applications. Supported
by the FMT1030 module.
Dynamic – assumes that the motion is highly
dynamic. Supported by the FMT1030 module.
High_mag_dep – heading corrections rely on the
magnetic field measured. To be used when
magnetic field is homogeneous. Supported by the
FMT1030 module.
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15
FMT1000-series — Motion Tracking Module With Output of Orientation, Inertial Motion Data and Magnetic Field
2 FMT1000-Series Architecture
Low_mag_dep – heading corrections are less dependent on the magnetic field measured. Heading is still based
on magnetic field, but more distortions are expected with less trust being placed on magnetic measurements.
Supported by the FMT1030 module.
VRU_general – Roll and pitch are the referenced to the vertical (gravity), yaw is determined by stabilized deadreckoning, referred to as Active Heading Stabilization (AHS) which significantly reduces heading drift, see also
section 7.2. Consider using VRU_general in environments that have a heavily disturbed magnetic field. The
VRU_general filter profile is the only filter profile available for the FMT1020 VRU, also supported by the
FMT1030 module
2.2.3
Frames of reference used in FMT1000-Series
The FMT1000-series module uses a right-handed coordinate system as the basis of the sensor of frame.
The following data is outputted in corresponding reference coordinate systems:
Table 6.
Frames of Reference used for FMT1000-Series Output
Data
Symbol
Acceleration
Reference Coordinate System
ax, ay, az
Sensor-fixed
Rate of Turn
ωx, ωy, ωz
Sensor-fixed
Magnetic Field
mx, my, mz
Sensor-fixed
Free Acceleration
Velocity Increment
Orientation Increment
ax, ay, az
Local Tangent Plane (LTP), default ENU
∆vx, ∆vy, ∆vz
Local Tangent Plane (LTP), default ENU
∆q0, ∆q1, ∆q2, ∆q3
Local Tangent Plane (LTP), default ENU
Euler angles, quaternions or rotation
Local Tangent Plane (LTP), default ENU
matrix
Local Tangent Plane (LTP) is a local linearization of the Ellipsoidal Coordinates (Latitude, Longitude, Altitude) in the
WGS-84 Ellipsoid.
Orientation
z
x
y
Figure 16.
Default Sensor fixed Coordinate System for the FMT1000-Series Module
Figure 1: Default sensor fixed coordinate system for the
It is straightforward to apply a rotation matrix
to the FMT,module
so that the velocity and orientation increments, free
FMT1000-series
acceleration and the orientation output is output using that coordinate frame. The default reference coordinate system
is East-North-Up (ENU) and the FMT1000-series has predefined output options for North-East-Down (NED) and
North-West-Up (NWU). Any arbitrary alignment can be entered. These orientation resets have effect on all outputs
that are by default outputted with an ENU reference coordinate system.
© 2015 Fairchild Semiconductor Corporation
FMT1000-series • Rev. 1.0
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16
FMT1000-series — Motion Tracking Module With Output of Orientation, Inertial Motion Data and Magnetic Field
3.1
3D Orientation Specifications
Table 7.
Orientation Specifications
Group
Parameter
Roll/pitch
Yaw (heading)
Typ.
Unit
Static
±2.0
deg
Allow filter initialization of at least 60 sec
Dynamic
±3.0
deg
Allow filter initialization of at least 60 sec
Static/dynamic,
Magnetic field referenced
±3.0
deg
FMT1030 AHRS only in a homogenous
magnetic field and a filter profile using
magnetic field as reference.
VRU_general filter profile
(unreferenced yaw)
5-10
deg after
60 min
Output data rate orientation
3.2
0-100
Comments
Active Heading Stabilization (AHS) feature.
See section 7.2 for more information.
Hz
Accuracy and latency independent of
output data rate. Output data rate may be
any integer divider of 100 Hz or may be
triggered by an external pulse (SYNC_IN)
Unit
Comments
Sensors Specifications
Table 8.
Gyroscope Specifications
Parameter
Full Range
Min.
Typ.
±2000
deg/s
Non-Linearity
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