Setting Up the Embedded Linux development environment

Kurva Prashanth · January 28, 2022

Embedded Linux   System Installation setup tools

The procedure for setting up a GNU/Linux host development environment to build the embedded linux application.

  • There are two ways to start with embedded Linux
    • Use tools provided and supported by vendors like MontaVista, Wind River or TimeSys. These tools comes with their own development and environment. These are mix of open-source components and proprietary tools.
    • Use community tools. These are completely open, supported by the community.
  • I prefer using community developed tools which are free softwares where we have access to source code or browse it moreover it respect user data.
    • However, knowing the concepts, switching to proprietary tools will be easy

OS for Linux development

I strongly recommend to use GNU/Linux as the desktop operating system to embedded Linux development, for multiple reasons.

  • All community tools are developed and designed to run on Linux. Trying to use them on other operating systems (Windows, Mac OS X) will lead to trouble.
  • As Linux also runs on the embedded device, all the knowledge gained from using Linux on the desktop will apply similarly to the embedded device.
  • If you are stuck with a Windows desktop, at least you should use GNU/Linux in avirtual machine (such as VirtualBox which is open source), though there could be a small performance penalty. With Windows 10, you can also run your favorite native Linux distro through Windows Subsystem for Linux (WSL2)

Desktop Linux distribution

  • To get started you need to download any good and sufficiently recent Linux desktop distribution that can be used for the development workstation
    • Debian, Fedora, openSUSE, Trisquel, etc.
  • I prefer Debian, it’s a free operating system, used by a wide range of organizations, large and small, as well as thousands of volunteers around the world work together on the Debian operating system, prioritizing Free and Open Source Software. .
  • make sure that you obtain a Linux distribution that is compatible with your hardware. For example, you might select a 32-bit i386 image or a 64-bit amd64 image.

For example, if you want to start with the Debian distribution, you can download an ISO-formatted image that you would use to install Debian Linux from https://www.debian.org/distrib/

Linux root and non-root users

Linux is a multi-user operating system. The root user is the administrator, and it can do privileged operations such as mounting filesystems, configuring the network, creating device files, changing thesystem configuration, installing or removing software. All other users are unprivileged, and cannot perform these administrator-level operations and the system has been configured so that the user account created first is allowed to run privileged operations through a program called sudo.

  • Example: sudo mount /dev/sda1 /mnt/disk

Software packages

The distribution mechanism for software in GNU/Linux is different from the onein Windows. Linux distributions provides a central and coherent way of installing, updating and removing applications and libraries: packages

  • Packages contains the application or library files, and associatedmeta-information, such as the version and the dependencies
    • .deb on Debian,.rpm on Red Hat, Fedora, openSUSE

Packages are stored in repositories, usually on HTTP or HTTPS servers. We should only use packages from official repositories for our distribution, unless strictly required.

Managing software packages

Instructions for Debian based GNU/Linux systems

  • Package repositories are specified in /etc/apt/sources.list and in files under /etc/apt/sources.list.d/

  • To update package repository lists:

    sudo apt update

  • To find the name of a package to install, the best is to use the search engine on https://packages.debian.org. You mayalso use:

    apt-cache search <keyword>

  • To install a given package:

    sudo apt install <package>

  • To remove a given package:

    sudo apt remove <package>

  • To install all available package updates:

    sudo apt dist-upgrade

  • Get information about a package:

    apt show <package>
  • Graphical interfaces
    • Synaptic for GNOME
    • KPackageKit for KDE

Further details on package management: https://www.debian.org/doc/manuals/debian-reference/ch02.en.html

Host vs. target

When doing embedded development, there is always a split between the host, the development workstation, which is typically a powerful PC. The target, which is the embedded system under development. These are connected by various means: almost always a serial line for debuggingpurposes, frequently a networking connection, sometimes a JTAG interface forlow-level debugging.

Serial line communication program

An essential tool for embedded development is a serial line communicationprogram, like HyperTerminal in Windows. There are multiple options available in Linux: Minicom,Picocom,Gtkterm,Putty,screen and the new tio(https://github.com/tio/tio).

  • we recommend using the simplest of them:Picocom
    • Installation with sudo apt install picocom
    • Run with picocom -b BAUD_RATE /dev/SERIAL_DEVICE.
    • Exit with [Ctrl][a] [Ctrl][x]
  • SERIAL_DEVICE is typically
    • ttyUSBx for USB to serial converters
    • ttySx for real serial ports
  • Most frequent command: picocom -b 115200 /dev/ttyUSB0

Command line

Using the command line is mandatory for many operations needed for embeddedLinux development. It is a very powerful way of interacting with the system, with which we can save a lot of time.

  • Some useful tips
    • We can use several tabs in the Gnome Terminal
    • Remember that you can use relative paths (for example:../../linux) in additionto absolute paths (for example: /home/user)
    • In a shell, hit [Control] [r], then a keyword, will search through the commandhistory. Hit [Control] [r] again to search backwards in the history
    • We can directly copy/paste paths from the file manager to Gnome Terminal by drag-and-drop.

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