Multitech MultiConnect xDot Instruction Manual

xDot®Developer Guide
for Japan

XDOT GUIDE FOR JAPAN
2 xDot®Developer Guide for Japan
xDot Guide for Japan
Models: MTXDOT-JP1
Part Number: S000666, Version 4.2
Copyright
This publication may not be reproduced, in whole or in part, without the specific and express prior written permission signed by an executive officer of
Multi-Tech Systems, Inc. All rights reserved. Copyright © 2022 by Multi-Tech Systems, Inc.
Multi-Tech Systems, Inc. makes no representations or warranties, whether express, implied or by estoppels, with respect to the content, information,
material and recommendations herein and specifically disclaims any implied warranties of merchantability, fitness for any particular purpose and non-
infringement.
Multi-Tech Systems, Inc. reserves the right to revise this publication and to make changes from time to time in the content hereof without obligation of
Multi-Tech Systems, Inc. to notify any person or organization of such revisions or changes.
Trademarks and Registered Trademarks
MultiTech, the MultiTech logo, MultiConnect, Conduit, and xDot are registered trademarks and mCard and mDot is a trademark of Multi-Tech Systems, Inc.
All other products and technologies are the trademarks or registered trademarks of their respective holders.
Legal Notices
The MultiTech products are not designed, manufactured or intended for use, and should not be used, or sold or re-sold for use, in connection with
applications requiring fail-safe performance or in applications where the failure of the products would reasonably be expected to result in personal injury or
death, significant property damage, or serious physical or environmental damage. Examples of such use include life support machines or other life
preserving medical devices or systems, air traffic control or aircraft navigation or communications systems, control equipment for nuclear facilities, or
missile, nuclear, biological or chemical weapons or other military applications (“Restricted Applications”). Use of the products in such Restricted
Applications is at the user’s sole risk and liability.
MULTITECH DOES NOT WARRANT THAT THE TRANSMISSION OF DATA BY A PRODUCT OVER A CELLULAR COMMUNICATIONS NETWORK WILL BE
UNINTERRUPTED, TIMELY, SECURE OR ERROR FREE, NOR DOES MULTITECH WARRANT ANY CONNECTION OR ACCESSIBILITY TO ANY CELLULAR
COMMUNICATIONS NETWORK. MULTITECH WILL HAVE NO LIABILITY FOR ANY LOSSES, DAMAGES, OBLIGATIONS, PENALTIES, DEFICIENCIES, LIABILITIES,
COSTS OR EXPENSES (INCLUDING WITHOUT LIMITATION REASONABLE ATTORNEYS FEES) RELATED TO TEMPORARY INABILITY TO ACCESS A CELLULAR
COMMUNICATIONS NETWORK USING THE PRODUCTS.
The MultiTech products and the final application of the MultiTech products should be thoroughly tested to ensure the functionality of the MultiTech
products as used in the final application. The designer, manufacturer and reseller has the sole responsibility of ensuring that any end user product into
which the MultiTech product is integrated operates as intended and meets its requirements or the requirements of its direct or indirect customers.
MultiTech has no responsibility whatsoever for the integration, configuration, testing, validation, verification, installation, upgrade, support or maintenance
of such end user product, or for any liabilities, damages, costs or expenses associated therewith, except to the extent agreed upon in a signed written
document. To the extent MultiTech provides any comments or suggested changes related to the application of its products, such comments or suggested
changes is performed only as a courtesy and without any representation or warranty whatsoever.
Contacting MultiTech
Sales Support
[email protected] [email protected]
[phone] [phone]
Website
www.multitech.com
Knowledge Base
For immediate access to support information and resolutions for MultiTech products, visit http://www.multitech.com/kb.go.
Support Portal
To create an account and submit a support case directly to our technical support team, visit: https://support.multitech.com.
Warranty
To read the warranty statement for your product, visit https://www.multitech.com/legal/warranty.
World Headquarters
Multi-Tech Systems, Inc.
2205 Woodale Drive, Mounds View, MN 55112
USA

CONTENTS
xDot®Developer Guide for Japan 3
Contents
Chapter 1 – Product Overview ................................................................................................................................. 7
Overview ....................................................................................................................................................................... 7
What's New in Firmware Version 4.1 ........................................................................................................................... 7
LoRaWAN 1.0.4 Support and Regional Parameters RP2 1.0.3.................................................................................. 7
Changes to Wake Pin.................................................................................................................................................. 7
Improved Boot Time from Sleep Mode..................................................................................................................... 7
AT Command Additions and Modifications ................................................................................................................ 7
Documentation Overview ............................................................................................................................................. 7
Related Documentation.............................................................................................................................................. 8
mbed Documentation ................................................................................................................................................... 8
Programming the xDot Microcontroller ..................................................................................................................... 8
General mBed Links .................................................................................................................................................... 8
xDot Platform ............................................................................................................................................................. 9
EUI and Networking ...................................................................................................................................................... 9
Configuration Persistence............................................................................................................................................. 9
Differential and Compressed Upgrade Files ................................................................................................................. 9
Product Build Options ................................................................................................................................................. 10
Chapter 2 – Getting Started ................................................................................................................................... 11
Getting Started with the xDot Developer Kit.............................................................................................................. 11
COM Port Enumeration by Operating System ............................................................................................................ 11
Linux.......................................................................................................................................................................... 11
Windows ................................................................................................................................................................... 11
Mac ........................................................................................................................................................................... 12
Updating Firmware Using the xDot Bootloader ......................................................................................................... 12
Chapter 3 – FOTA ................................................................................................................................................... 14
External Flash Components for FOTA ......................................................................................................................... 14
FOTA (FUOTA) Overview............................................................................................................................................. 14
FOTA Stages .............................................................................................................................................................. 15
Potential Problems.................................................................................................................................................... 17
Troubleshooting FOTA .............................................................................................................................................. 17
Chapter 4 – Mechanical Drawings with Pinouts ..................................................................................................... 20
xDot............................................................................................................................................................................. 20
Chapter 5 – Specifications and Pin Information...................................................................................................... 21
MTXDOT Specifications............................................................................................................................................... 21
Japanese Models (MTXDOT-JP1) .............................................................................................................................. 22
Battery Draw Down..................................................................................................................................................... 23
Electrical and Timing Characteristics ........................................................................................................................ 23

CONTENTS
4 xDot®Developer Guide for Japan
Measuring the Power Draw ...................................................................................................................................... 24
Pin Information .......................................................................................................................................................... 25
Pin Information ......................................................................................................................................................... 25
Pull-Up/Down............................................................................................................................................................ 27
LoRa........................................................................................................................................................................... 27
Crystals/Oscillator ..................................................................................................................................................... 27
Sleep Wake and Deep Sleep Wake Pins ................................................................................................................... 27
Interrupt Limitations................................................................................................................................................. 28
xDot Pinout Design Notes ........................................................................................................................................... 29
Serial Pinout Notes.................................................................................................................................................... 29
Serial Settings.............................................................................................................................................................. 29
LoRa ............................................................................................................................................................................ 29
Throughput Rates...................................................................................................................................................... 29
Range ........................................................................................................................................................................ 29
Resetting the xDot ...................................................................................................................................................... 31
Chapter 6 – Antennas ............................................................................................................................................ 32
Antenna System ......................................................................................................................................................... 32
U.FL and Trace Antenna Options ............................................................................................................................... 32
LoRa Antenna.............................................................................................................................................................. 33
LoRa Antenna Specifications .................................................................................................................................... 33
RSMA-to-U.FL Coaxial Cables ..................................................................................................................................... 34
Coaxial Cable Specifications ..................................................................................................................................... 34
Ethertronics Chip Antenna.......................................................................................................................................... 35
Antenna Specifications ............................................................................................................................................. 35
Stackup Information.................................................................................................................................................... 35
Developer Board Layer Stackup................................................................................................................................ 35
Stackup Table............................................................................................................................................................ 36
Impedance ................................................................................................................................................................ 36
Chip Antenna Design Guidelines................................................................................................................................. 38
Antenna Pad Layout.................................................................................................................................................. 39
PCB Layout ................................................................................................................................................................ 39
Antenna Matching Network........................................................................................................................................ 40
915 ............................................................................................................................................................................ 40
868 ............................................................................................................................................................................ 41
OEM Integration ......................................................................................................................................................... 41
FCC & IC Information to Consumers ......................................................................................................................... 41
FCC Grant Notes........................................................................................................................................................ 41
Host Labeling............................................................................................................................................................... 42
Chapter 7 – Safety Information .............................................................................................................................. 43
Handling Precautions .................................................................................................................................................. 43
Radio Frequency (RF) Safety ....................................................................................................................................... 43

CONTENTS
xDot®Developer Guide for Japan 5
Sécurité relative aux appareils à radiofréquence (RF).............................................................................................. 43
Interference with Pacemakers and Other Medical Devices ...................................................................................... 44
Potential interference............................................................................................................................................... 44
Precautions for pacemaker wearers ........................................................................................................................ 44
Device Maintenance ................................................................................................................................................... 44
User Responsibility...................................................................................................................................................... 45
Chapter 8 – Regulatory Information....................................................................................................................... 46
EMC, Safety, and Radio Equipment Directive (RED) Compliance .............................................................................. 46
47 CFR Part 15 Regulation Class B Devices ................................................................................................................. 46
FCC Interference Notice ............................................................................................................................................. 46
FCC Notice................................................................................................................................................................... 46
Industry Canada Class B Notice................................................................................................................................... 47
Chapter 9 – Environmental Notices........................................................................................................................ 48
Waste Electrical and Electronic Equipment Statement .............................................................................................. 48
WEEE Directive.......................................................................................................................................................... 48
Instructions for Disposal of WEEE by Users in the European Union ........................................................................ 48
REACH Statement ....................................................................................................................................................... 48
Registration of Substances........................................................................................................................................ 48
Restriction of the Use of Hazardous Substances (RoHS) ............................................................................................ 49
Information on HS/TS Substances According to Chinese Standards ......................................................................... 50
Information on HS/TS Substances According to Chinese Standards (in Chinese) ...................................................... 51
Chapter 10 – Labels................................................................................................................................................ 52
Label Examples............................................................................................................................................................ 52
Chapter 11 – Developer Kit Overview .................................................................................................................... 53
xDot Developer Kit ..................................................................................................................................................... 53
Developer Kit Package Contents............................................................................................................................... 53
Firmware Updates..................................................................................................................................................... 53
Programming Devices in Production ........................................................................................................................ 53
xDot Developer Kit Mechanical Drawings................................................................................................................... 54
Micro Developer Board LEDs ...................................................................................................................................... 55
Chapter 12 – Developer Board Schematics............................................................................................................. 56
Assembly Diagrams and Schematics ........................................................................................................................... 56
Assembly Diagrams................................................................................................................................................... 56
Schematics ................................................................................................................................................................ 58
Chapter 13 – Design Considerations....................................................................................................................... 62
Noise Suppression Design........................................................................................................................................... 62
PC Board Layout Guideline ......................................................................................................................................... 62
Electromagnetic Interference .................................................................................................................................... 62
Electrostatic Discharge Control................................................................................................................................... 63

CONTENTS
6 xDot®Developer Guide for Japan
Chapter 14 – Mounting xDots and Programming External Targets ......................................................................... 64
Mounting the Device on Your Board .......................................................................................................................... 64
Stencil........................................................................................................................................................................ 64
Solder Profile............................................................................................................................................................... 64
Setpoints (Celsius)..................................................................................................................................................... 65
xDot Packing ............................................................................................................................................................... 65
In-System Programming of xDot................................................................................................................................. 66
Schematic Example ................................................................................................................................................... 66
Recommended Programming Hardware for Production.......................................................................................... 67
JTAG/SWD Connector .............................................................................................................................................. 67
Appendix A – Appendix A Release Note Archive .................................................................................................... 68
What's New in Firmware Version 3.2 ......................................................................................................................... 68
LoRaWAN Version 1.0.3 Class B Support .................................................................................................................. 68
Russian Channel Plan Support .................................................................................................................................. 68
AT Command Additions and Modifications .............................................................................................................. 68
What's New in Firmware Version 3.3 ......................................................................................................................... 68
LoRaWAN Version 1.0.4 Changes ............................................................................................................................. 68
Pin Output Changes .................................................................................................................................................. 69
AT Command Additions and Modifications .............................................................................................................. 69
What's New in Firmware Version 4.0 ......................................................................................................................... 70
Configuration Persistence......................................................................................................................................... 70
FOTA Enhancements................................................................................................................................................. 70
AT Command Additions and Modifications .............................................................................................................. 70
Index...................................................................................................................................................................... 72

PRODUCT OVERVIEW
xDot®Developer Guide for Japan 7
Chapter 1 – Product Overview
Overview
The MultiConnect xDot (MTXDOT) is a LoRaWANTM, low-power RF device, capable of two way communication over
long distances, deep into buildings, or within noisy environments*using the unlicensed ISM bands in North
America, Europe and worldwide. The xDot is a compact surface-mount device with an mbed enabled processor and
enhanced security. The xDot features an integrated ARM®Cortex®-M3 processor and mbedTM compatible software
library for developers to control, monitor and bring edge intelligence to their Internet of Things (IoT) applications.
*Actual distance depends on conditions, configuration, antennas, desired throughput, and usage frequency. In
dense urban environments, a typical range is 1-2 miles.
What's New in Firmware Version 4.1
The new release includes the following changes:
LoRaWAN 1.0.4 Support and Regional Parameters RP2 1.0.3
Changes to Wake Pin
Improved boot time from Sleep Mode
New and updated AT Commands
LoRaWAN 1.0.4 Support and Regional Parameters RP2 1.0.3
Adds AS923-4, extending support to Israel.
Changes to Wake Pin
Ability to set trigger for WAKE pin as rising, falling, or either.
Improved Boot Time from Sleep Mode
Reduced xDot boot time waking from deep sleep by moving scan for external flash to start of fragmentation
session instead of at boot.
AT Command Additions and Modifications
Note: For AT Command details, refer to S000768 xDot AT Command Reference Guide .
Changed AT+ERASE=1 so that it only erases the area of external flash used for FOTA if present on xDot.
Added AT+ERASE=2 erase configuration in the EEPROM for xDot.
Changed AT+WP added trigger parameter and mode parameter to set pullup/pulldown.
Added AT+DUTY set duty cycle maximum or per band.
For an archive of release notes, go to Appendix A.
Documentation Overview
This manual is one part of xDot documentation. Refer to the Related Documentation and mbed sections for
additional information needed to program your xDot and integrate your application with the MultiConnect Conduit
gateway.
This document includes:

PRODUCT OVERVIEW
8 xDot®Developer Guide for Japan
xDot device information: including mechanical drawings, specifications, safety and regulatory information,
and other device specific content.
Developer Kit information: including design considerations, schematics, and installation and operation
information.
This current version of this manual is available at www.multitech.com/support.
Related Documentation
xDot AT Command Guide: Includes details on the AT commands available for xDots.
MultiTech Developer Site: Application notes, LoRa information, and documentation for related products
such as the MultiConnect Conduit (MTCDT) gateway and the LoRa accessory card (MTAC-LORA) are available
on the MultiTech developer site. This site includes information on using the Conduit with xDots. Go to:
www.multitech.net
Processor Datasheet: ST ARM®Cortex®-M3 processor (STM32L151CCU6) datasheet is available on the ST
website: http://www.st.com/resource/en/datasheet/stm32l151cc.pdf
mbed Documentation
ARM mbed is a free, open-source platform and operating system for embedded devices using the ARM Cortex-M
microcontrollers. The mbed website provides free software libraries, hardware designs, and online tools for rapid
prototyping of products. The platform includes a standards-based C/C++ SDK, a microcontroller HDK, and
supported development boards, an online compiler and online developer collaboration tools.
Note: To send and receive data, you need a LoRaWAN 1.0 gateway, such as MultiTech's Conduit (MTCDT) with
an MTAC-LORA accessory card installed.
Programming the xDot Microcontroller
Note: To program an xDot application, you need the xDot Developer kit, which includes an xDot mounted on a
developer board.
Use the ARM mbed ecosystem to program the microcontroller. Compile in the cloud or locally, copy the resulting
binary file to the mbed USB drive, and reset the xDot.
On the xDot mbed page, MultiTech supplies source code for non-RF portions of the xDot. To comply with FCC and
ETSI certification, some portions of the software is available only as binary libraries.
MultiTech offers both development and stable release versions of the library.
Development version: libmxDot-dev-mbed6
Stable release version: libmxDot-mbed6
You can use either the mbed online compiler or offline tools.
Online: Use the mbed-os library in your mbed application
Offline: Use mbed-cli tools to create, manage, and build your mbed 6.0 application.
General mBed Links
Explore mbed: https://os.mbed.com/
Getting Started with mbed: https://os.mbed.com/docs/mbed-os/#gettingstarted
mbed Handbook: https://os.mbed.com/docs/mbed-os

PRODUCT OVERVIEW
xDot®Developer Guide for Japan 9
mbed online compiler documentation: https://os.mbed.com/docs/mbed-os/latest/quick-start/online-with-
the-online-compiler.html
mbed cli documentation: https://os.mbed.com/docs/mbed-os/latest/quick-start/offline-with-mbed-cli.html
mbed workspace tools documentation: https://os.mbed.com/docs/mbed-os/v6.1/build-tools/index.html
xDot Platform
The xDot mbed page includes the xDot library, firmware, and test cases
https://developer.mbed.org/platforms/MTS-xDot-L151CC/
EUI and Networking
xDots have an Extended Unique Identifier (EUI). To query the device for the EUI, AT+DI:
AT+DI=<8-BYTE-HEX-MSB>
AT+DI=001122AABBCCDDEE
For information on setting up xDots as part of a LoRa network, go to www.multitech.net.
Configuration Persistence
To safeguard your configuration, the device offers configuration persistence in the form of configuration
redundancy and wear leveling.
Note: These features change the configuration storage and make the firmware update a one way process. The
configuration is not backward compatible to any version less than 4.0.x. Once a device is flashed with 4.0.x
firmware, the configuration is converted to a new format. Any versions earlier than 4.0.x cannot parse this new
format.
Redundancy
In case of data loss or corruption, your device stores multiple copies of the configuration and can fall back to the
last good copy.
Wear Leveling
Wear leveling writes across the entire flash sector and skips bad sections on write failure. Frequently saved session
parameters have more flash space available to extend the expected life of the flash system on your device.
Differential and Compressed Upgrade Files
Differenital and compressed upgrade files can be used to reduce the size of firmware upgrades sent over-the-air
(FOTA). Smaller files reduce the time required to deliver an update. Smaller FOTA sessions increase end-device
battery life.
Creating Differential and Compressed Files
To package application firmware binaries for Dot devices with compression or deltas, use the mtsmultitool utility.
The output is a binary file that can be sent to the bootloader over serial YMODEM or FOTA.
For more details on the utility, see: https://pypi.org/project/mtsmultitool/ .
The utility requries Python v3.8 installed. To install the utility, open a command prompt and enter: pip install
mtsmultitool

PRODUCT OVERVIEW
10 xDot®Developer Guide for Japan
Product Build Options
Product Description Package Quantity
Japan
MTXDOT-JP1-A00 AS923 MHz LoRa Module w/LBT UFL/TRC (JP) 1 or 100
Developer Kits
MTMDK-XDOT-JP1-A00 MultiConnect xDot Micro Developer Kit - Includes a AS923 w/LTB MHz xDot
Note:
The complete product code may end in .Rx. For example, MTXDOT-JP1-A00.Rx, where R is revision
and x is the revision number.

GETTING STARTED
xDot®Developer Guide for Japan 11
Chapter 2 – Getting Started
Getting Started with the xDot Developer Kit
Getting started depends on what you want to do. By default, xDot ships with firmware that supports AT
Commands that use the serial I/O. For AT Commands, refer to the separate MultiConnect Dots AT Command
Reference Guide.
Two serial interfaces are available through the USB interface, one is used to send AT commands to the xDot and
the other is for debug messages. Refer to Chapter 4, Specifications and Pin Information for information on which
pins are available out of the box.
Before starting your project development, make sure you have the latest firmware for the Developer Kit and xDot.
Go to the xDot mbed page for firmware. https://developer.mbed.org/platforms/MTS-xDot-L151CC/
To send commands to the xDot:
1. Plug the developer board into a USB port.
2. Open communications software, such as TeraTerm, Putty, or Minicom.
3. Set the following:
Baud rate = 115,200
Data bits = 8
Parity = N
Stop bits = 1
Flow control = Off
To develop using Mbed, the xDot Mbed page includes libraries and test cases. Refer to mbed Documentation for
details and links.
For help setting up a MultiConnect®Conduit®to send data to and from an xDot, refer to Related Documentation .
COM Port Enumeration by Operating System
xDots create an AT Commands port and a debug port.
Linux
The following COM ports are created on Linux systems:
/dev/ttyACMx
/dev/ttyACMy
Where x and y may be 0 and 1, 3 and 4, etc.
The COM port with lower number is the AT command port and COM port with the higher number is the debug
port.
Windows
On Windows systems, COM ports appear in the Device Manager:
Debug Port: Mbed Serial Port

GETTING STARTED
12 xDot®Developer Guide for Japan
AT Command Port: XR21V1410 USB UART
You may need to install a driver for the debug port to function properly. Go to:
https://developer.Mbed.org/handbook/Windows-serial-configuration
Mac
On Mac systems, COM ports appear in the Device Manager as:
/dev/cu.usbmodemx
Where x is a string of numbers and possibly letters, ending in a number.
The COM port with lower number is the AT command port and COM port with the higher number is the debug
port.
Updating Firmware Using the xDot Bootloader
The xDot bootloader allows firmware upgrades either via YMODEM through command or debug serial ports at
115,200 bps.
For firmware versions 3.3.5 and lower:
To enter the bootloader, enter the characters xdt on either serial port upon processor reset. The bootloader allows
250ms for x and then 500 ms each for d and t. If these timers expire before receiving the proper character or
another character is received, the bootloader jumps to the application code.
For firmware versions 4.0. and higher:
To enter the bootloader, enter the characters m t s on the AT command port with 250ms between characters. Any
single character on the debug port enters the bootloader for all versions of the bootloader. If these timers expire
before receiving the proper character or another character is received, the bootloader jumps to the application
code.
The bootloader includes an option to upgrade application code via YMODEM or jump to the application
code. During the YMODEM file transfer, the new application is programmed directly into the STM32L151CC
flash memory.
Since the new application is directly programmed into the STM32L151CC flash memory and the xDot has no
on board memory to back up the old application, recovery from failed download is the responsibility of the
host system.
The Mbed build process creates two files when building for the bootloader. The
name_of_program_application.bin file is the application with the correct offset that can be transferred via
YMODEM onto the xDot using the bootloader. The name_of_program.bin file is the entire program with the
bootloader than can be flashed on using jtag (this file cannot be transferred onto the xdot via YMODEM).
To build xDot firmware with the bootloader, you must include the bootloader.bin file in the Mbed-os directory
along with an Mbed_app.json file that includes directives describing the space used for the bootloader and the
location where the bootloader.bin file resides.
Note: For an application to run at the correct offset, it needs location where it will reside so the vector
table is correct.
Mbed-os version 5.5.4, includes hooks that allow you to easily add a boot loader for the xDot. Go to
https://docs.Mbed.com/docs/Mbed-os-handbook/en/latest/advanced/bootloader/ for details.

GETTING STARTED
xDot®Developer Guide for Japan 13
For the bootloader, create a file with the following content. (Actual size may vary, but needs to
accommodate the bootloader size.) Name the file Mbed_app.json and place it in the root directory.
{
"target_overrides": {
"XDOT_L151CC": {
"target.restrict_size": "0x8000"
}
}
}
For the application, create a file with the following content. Name it Mbed_app.json and place it in the root
directory.
{
"target_overrides": {
"XDOT_L151CC": {
"target.bootloader_img": "bootloader_location/bootloader.bin"
}
}
}

FOTA
14 xDot®Developer Guide for Japan
Chapter 3 – FOTA
External Flash Components for FOTA
AT firmware on the xDot supports FOTA when a compatible external flash component or block device is connected
to the xDot. In this configuration, multicast and fragmentation sessions are managed by the xDot. Messages for
multicast (port 200) and fragmentation (port 201) are handled by the xDot and are not passed through to the AT
terminal.
File space is statically allocated. There is no traditional file system. The xDot will reserve space for new application
firmware, a backup of the current application, and an upgrade result file. A total of 436 KB (0x6A000 bytes) of free
space is required.
External Flash Component Requirements
For a flash component or block device to work with the xDot, it must meet the following criteria:
Work with MBed OS DataFlashBlockDevice or SPIFBlockDevice classes
Maximum 4 KB sector erase size
Maximum 512 byte page size
SPIF type components must support Serial Flash Discoverable Parameters (SFDP)
External Flash Components Tested for Compatibility
Part Number Type Manufacturer Density Page Size Erase Size
MX25R8035 SPIF Macronix 8 MB 512 bytes 4 KB
AT45DB041E DATAFLASH Adesto 4 MB 256 bytes 2 KB
Host MCU
When no external flash component is present, fragmentation messages (port 201) must be handled by a host MCU
implementing the Fragmented Data Block Transport.
FOTA (FUOTA) Overview
This requires xDot firmware Version 4.0 or higher and a Conduit®with AEP (mPower) 5.2 or higher.
Firmware Over the Air (FOTA) also known as Firmware Upgrade Over the Air (FUOTA) is a way to upgrade Dot end
devices using multicast and file fragmentation packages defined in the LoRaWAN specification. FOTA allows the

FOTA
xDot®Developer Guide for Japan 15
Conduit to update the firmware on many Dots at once using multicast and error correction packets. FOTA is still in
its early stages of revision and does have potential problems, which are included in this topic.
Note: FOTA is enabled by default.
To start the FOTA process, the Conduit sends two setup downlinks to the Dot. First, the Conduit then sends a
multicast session setup request to the Dot. The Dot responds with a multicast session setup answer. The Conduit
sends a fragmentation setup request. The Dot responds by sending back a fragmentation setup answer. Once
setup is complete, the Dot waits until the start of the multicast session. At the start of the session, the Dot
switches to class C with the specified data rate and frequency to receive the file fragments sent by the Conduit.
After the file fragments are sent, the Conduit starts sending parity fragments. At any point when the Dot is able to
reconstruct the firmware file, the CRC is calculated and the CRC message id sent in Class A. This could happen any
time after the last fragment is sent to after the last parity is sent.
For details on the FOTA AT Commands, go to xDot AT Command Reference Guide (S000768).
FOTA Stages
A FOTA session has four stages: 1) session setup, 2) fragmentation, 3) parity, and 4) verification.
Session Setup
For a multicast session to work with class A devices, a start time must be agreed upon by the network server and
each device. This requires the devices to synchronize their time with the server. These critical tasks are done
during session setup.
Class A devices must periodically send uplinks to open downlink windows making the time required to complete an
operation setup directly tied to the frequency of device uplinks. For each device involved in the operation, some
extra time should be added to the total setup time to account for latency in queuing each device’s message.
Setup messages are sent up to 3 times. Worst-case timing for operation setup would be ((3 * device_uplink_period
* 2) + (overhead * number_of_devices)).
The included diagram illustrates the events that occur during a best-case setup with no messages missed and well-
timed device uplinks. Each device follows these steps:
1. FOTA operation queues Multicast setup message with network server.
2. Device sends an uplink.
3. Multicast setup message is downlinked to the device.
4. Device sends a multicast setup response.
5. FOTA operation queues fragmentation setup message.
6. Device sends an uplink.
7. Fragmentation setup is downlinked to the device.
8. Device sends a fragmentation setup response from device.

FOTA
16 xDot®Developer Guide for Japan
Fragmentation
During this stage, the device should only send uplinks as necessary, too many can cause excessive fragment loss.
Applications on the device should not perform heavy processing activities during FOTA. Doing so can cause
fragments to overlap and excessive fragment loss. The number of fragments required to send a file depends on the
Data Rate. The device clears the file system to ensure enough free space to save update firmware and a backup
copy of the current firmware saved by the bootloader. User files are removed when the fragmentation session is
set up.
Parity
Multicast messages are unconfirmed meaning some loss of fragments is expected. The device can recover a certain
number of fragments though parity.

FOTA
xDot®Developer Guide for Japan 17
The xDot can tolerate up to 150 lost fragments.
Verification
Once a device completes its fragmented file, it calculates a CRC64 and sends a request to the server to verify the
CRC. The server sends a response indicating if the CRC matches or not. If the CRC is verified the device reboots and
performs the upgrade. If the CRC does not match, the downloaded file is discarded.
Potential Problems
If the Dot misses either setup message, the FOTA session will not be successful. The Dot attempts to receive
both messages multiple times. If the Dot is unsuccessful, it resets the fragmentation sessions and multicast
session.
If the Dot does not receive a CRC response from the Conduit, it resets the fragmentation and multicast
sessions and deletes the fragmentation file.
The Dot can reset the multicast/fragmentation session at any time using AT+FOTA=2.
When using AT+SLEEP, make sure to wake up the Dot before a scheduled FOTA session. Using AT+FOTA=3
will return the time in seconds before the FOTA session is scheduled to start.
If AT+SLEEP is used during the FOTA session, the Dot will miss packets and the session will likely fail.
The FOTA session sends down packets every 1.5 seconds (assuming no duty cycle) and parity packets every
3 seconds by default. For best results, Multitech recommends users suspend all normal Dot operations until
the FOTA session is complete.
Troubleshooting FOTA
Troubleshooting FOTA on the Dot
Problem: Dot does not receive any file fragments.
Troubleshooting:
The Dot must receive two setup messages for the FOTA session to work, fragmentation setup request
and multicast setup request.
Verify if the Dot received the fragmentation setup request. This comes down on port 201. When the
Dot receives this request, it sends an answer. Check the Dot debug log for Sending Fragmentation
Response.
After sending the fragmentation response, the Dot receives a multicast setup request. Check for this
message on port 201. The Dot responds with a multicast setup answer. Check the Dot debug log for
Sending Multicast Response.
Make sure the Dot is in Class C at the start of the FOTA session (AT+DC). The Dot must also be awake
and will not wake up to start the FOTA/Multicast session. The command AT+FOTA=3 displays the time
before a FOTA session starts.
Make sure the Conduit is sending the fragments by checking the Conduit logs in /var/log/log_fota*.
Problem: Dot cannot complete the FOTA session.
Troubleshooting:
If the Dot misses too many packets, the FOTA session cannot be completed.

FOTA
18 xDot®Developer Guide for Japan
If the Dot was able to reconstruct the file using parity fragments, it sends a CRC check to the Conduit.
Check the Dot debug log for Sending CRC. If the Dot does not receive a response or the Conduit
responds with CRC not correct, the Dot discards the file.
Problem: Dot fails to process parity fragments.
Troubleshooting:
If the Conduit sends parity fragments faster than the Dot can process them, the Dot starts failing to
properly receive the fragments. This results in failed MIC checks or wrong address, which is noted in the
Dot debug log.
To correct this, increase the delay between parity fragments on the Conduit.
Problem: Dot is unexpected state.
Troubleshooting:
If the Dot is in a bad or unknown state, use ATZ to reset the Dot and clear the multicast and FOTA
states. AT+FOTA=2 also resets FOTA and Multicast states.
Troubleshooting FOTA on the Conduit
Problem: FOTA Session not starting.
Troubleshooting:
Verify that there is not a current FOTA session. If there is no current FOTA session and a FOTA session
will not start, reboot the Conduit.
If the Conduit does not receive at least one response from an Dot, the FOTA session will not start. The
process will go from SETUP (10%) to TEARDOWN (90%). Check the log (/var/log/log_fota*) to make sure
the Conduit is receiving the setup answers.
Problem: FOTA Session not successful.
Troubleshooting:
For a FOTA Session to be successful, the Dot has to be able to reconstruct the file. If the Dot misses too
many packets, the FOTA session will not be successful and the Dot will not send a CRC to the Conduit.
If the Conduit receives a CRC from an Dot check the FOTA log (/var/log/log_fota*) to make sure the CRC
matches the Conduit and the CRC correct answer is sent back to the Dot. Check the Dot debug log to
verify if the device received the CRC answer.
Problem: Stop FOTA Session / FOTA Session won’t start (FOTA in progress) / Stop Multicast Session
Troubleshooting:
To end a FOTA session that is in progress, send 'ps -A | grep fota'. Find the PID associated with lora-fota
(not lora-fota-demo). Then send 'kill (pid of lora-fota)'.
Also send 'rm -r -f ~/.fota/'. Devices may be in Class C or Class A depending on the FOTA session status
before it ended. Make sure to change the devices back to their appropriate class. Make sure the FOTA
daemon is running by '/etc/init.d/fotad restart'.

FOTA
xDot®Developer Guide for Japan 19
To end a Multicast session that is in progress, use 'ps -A | grep mcm'. Find the PID associated with lora-
mcm. Then use 'kill (pid of lora-mcm)'. Also send 'rm -r -f ~/.fota/'.
Wiping out the .fota directory removes any future FOTA/multicast sessions scheduled that have not
setup.

MECHANICAL DRAWINGS WITH PINOUTS
20 xDot®Developer Guide for Japan
Chapter 4 – Mechanical Drawings with Pinouts
xDot
Note: The xDot development board uses a land pattern that matches the xDot land pattern in the previous
image. All pads are 0.028 inches square except the large one, which is 0.098 inches x 0.028 inches.