The Myriota FlexSense provides an off-the-shelf ready-to-go hardware solution for IoT sensing and monitoring applications with Myriota’s bi-directional, direct-to-orbit (D2O) satellite communications. The Myriota Flex SDK provides users with the necessary boilerplate to get started writing custom application firmware for the Myriota FlexSense. See the full docs here and find the source code here.

Remarks: Source code for reference applications using the Flex SDK can be found here. Pre-built binaries of the reference applications can be found here. N.B. These reference applications should be used for lab testing only and are not suitable for production environments.

Building applications

The Flex SDK currently supports building applications on Ubuntu 22.04. Other platforms can be supported through the use of DevContainer from within VSCode or via Github Codespaces.

Detailed setup instructions are outlined in the following sections:

Ubuntu 22.04
DevContainer on Windows
Github Codespaces

Programming devices

Myriota supports programming of the FlexSense from any version of Linux, Windows and Mac that support the installation of the 'python3.10' and it's corresponding version of 'pip'.

Build Environment Setup

Setting up Ubuntu 22.04

Install packages

Install these packages with apt:

sudo apt install \
  git \
  curl \
  xxd \
  meson \
  ninja-build \
  gcc \
  python3 \
  python3-pip \
  python-is-python3

Remarks

If you install these programs via other methods then make sure they meet these version requirements:

meson >= 0.61.2
ninja >= 1.10.1
python >= 3.10.12

You can ignore the gcc version as it is only installed as a requirement of meson native builds, but not actually used in the cross building process.

Install GNU ARM Toolchain

Myriota uses the GNU ARM Toolchain version 7.2.1 to compile user applications for the Myriota FlexSense. Myriota hosts its own copy of this toolchain and it can be installed in /opt/gcc-arm/ with the command:

sudo ./scripts/install_arm_toolchain.sh

Important: You must update your PATH variable to to include the toolchain. i.e. Add export PATH="${PATH}:/opt/gcc-arm-13_2_1/bin" to your ~/.profile or wherever you configure your environment variables for your given shell.

Install Python Requirements

Install the correct python environment with:

pip3 install -r requirements.txt

Remarks: For simplicity we install the python packages globally, but you can also use a python virtual environment. See here for details.

Downloading libflex and system_image binaries

The libflex.a and system_image.bin binaries must downloaded and installed in the correct location, in order to perform a build. This can be achieved by running the following command:

python scripts/download_binaries.py

Important: You require valid Myriota Device Manager credentials in order to download the binaries. The script will prompt you to supply them.

Setting Up DevContainer on Windows

To build applications using a DevContainer on Windows you should first install VSCode. When you open the Flex SDK folder in VSCode it should direct you through the steps that are required to setup your DevContainer. Once you have the DevContainer open in a terminal you will be able to perform the build instruction.

Setting Up Github Codespaces

Codespaces is a cloud development environment provided by Github. Further information on how to use Codespaces is available in the Github documentation.

Remarks: Note that using Codespaces may incur a cost. Refer to the Github documentation for details regarding pricing, storage, and usage.

Building The User Application

1. Setup

The following build instructions assume your current working directory is the project root. Configure the build with the following command (this only needs to be run once):

meson --cross-file ./flex-crossfile.ini build

Important: Make sure to provide the --cross-file ./flex-crossfile.ini otherwise the build will fail.

Setup Options

1. Skip GNSS

To assist development where a GPS signal is difficult to obtain, for example an indoor environment, the Flex SDK provides the skip_gnss option.
By default the skip_gnss option is disabled. To enable this option in the build, simply add -Dskip_gnss=true in the setup step, before building:

meson -Dskip_gnss=true --cross-file ./flex-crossfile.ini build

Important: During production builds, please validate that the skip_gnss option is disabled (set to false), to ensure correct operation of the FlexSense device.

2. Build

Then to perform the build simply run the command:

meson compile -C build

Important: After building the source the compiled user application will be available under the build/ directory as user_application.bin. You can also find compiled versions of examples under build/examples/.

Remarks: You can find the source code of the examples in the following directory examples.

Pristine Build

To perform a pristine build, delete the build folder before running the setup and build commands again.

Programming The FlexSense

Programming a FlexSense device requires the flashing of two separate images:

System Image or 'system_image.bin'
User Application or 'user_application.bin'

Important: The System Image only needs to be flashed once during development or on the release of a new Flex SDK. The User Application is what you will be developing so update it as you need. If you flash the System Image you must re-flash the User Application.

The instructions below outline how to program the System Image and User Application via the command line. Myriota also provides the DeviceAssist GUI tool for programming devices. The DeviceAssist tool is available from the Tools section of the Myriota Support Site.

Programming On Linux

The following programming instructions assume your current working directory is the project root. To program the System Image run:

./scripts/updater.py -f ./subprojects/libflex/system_image/system_image-*.bin

To program the User Application:

./scripts/updater.py -m ./build/user_application.bin

Programming On Windows

Install Python and Python Requirements

Programming the FlexSense requires Python version 3.10 or greater.

The following instructions can be used to install Python on a Windows platform.

Important: The following commands should be all performed from within a Windows Terminal Shell (CMD or PowerShell).

Install python:

winget install -e --id Python.Python.3.10

Then navigate the Flex SDK projects root directory, and run the following:

pip3 install -r requirements.txt

Programming instructions

The following programming instructions assume your current working directory is the project root. To program the System Image run:

python .\scripts\updater.py -f .\subprojects\libflex\system_image\system_image-*.bin

To program the User Application run:

python .\scripts\updater.py -m .\build\user_application.bin