Let's try developing GUI applications with TorizonOS + Verdin iMX95.

Introduction

This article describes how to develop a GUI application using Docker containers on Torizon OS, using Toradex's Verdin iMX95 SOM and Mallow carrier board.

The Verdin iMX95 SOM is a system-on-module (SOM) equipped with the NXP i.MX95 processor. Leveraging Toradex's software support and long-term supply chain, you can continuously use the same platform from proof-of-concept (PoC) and prototype development to mass production.

Furthermore, in recent years, regulatory movements such as the Cyber Resilience Act (CRA) have led to a growing demand for continuous vulnerability countermeasures and software updates in industrial equipment. Against this backdrop, Torizon OS, which provides OTA updates and long-term software maintenance, is attracting attention.

The specific details are as follows:

• Installing Torizon OS on Verdin iMX95
• Enabling a 10.1-inch LVDS-connected DISPLAY
• Running a GUI application using Python and GTK within a Docker container
• Editing applications from within a container

This article is intended for users who are familiar with basic terminal operations on Ubuntu. While it explains the process without prior knowledge of Docker or Device Tree Overlay, please review the commands before executing them.

Precautions

• This article will use a Verdin iMX95 SOM in combination with a Mallow carrier board.
• Please use a USB serial conversion CABLES that supports 1.8V, which is compatible with the UART voltage of the target board.
• For UART connections, ensure that TX, RX, and GND are correctly connected. Do not connect the VCC pin.
• Connecting a USB serial conversion CABLES designed for 3.3V may damage the target board.
• An internet connection is required to download OS images, Docker images, and packages.
• After your initial login, please be sure to change your initial password.

System Configuration

From now on, the PC running Ubuntu 22.04 will be referred to as the host PC, and the device combining the Verdin iMX95 SOM and the Mallow carrier board will be referred to as the target board.

This article will utilize DISPLAY 's built-in functionality; TOUCH PANELS functionality will not be covered.

Verdin iMX95 SOM and Carrier Board

The Verdin iMX95 SOM is a System on Module (SOM) that modularizes components such as the CPU, memory, POWER SUPPLIES circuitry, and high-speed interfaces.

By using SOM, you can reduce the design burden of SoC peripheral circuits, allowing you to focus on carrier board design and application development. As a result, you can expect shorter development times and reduced design risks.

Overview of Torizon OS

A carrier board is a circuit board that extracts interfaces such as USB, Ethernet, DISPLAY, camera, and GPIO from the SOM and uses them according to the product application. Separating the SOM and carrier board makes it easier to design I/O configurations and CONNECTORS placements according to the application.

Torizon OS is a Linux platform for embedded devices provided by Toradex.

Overview of Torizon OS

Torizon OS is based on embedded Linux using the Yocto Project. Because applications can be developed and run as Docker containers, it's easier to separate application dependencies from the OS itself.

This article will guide you through setting up a Python and GTK execution environment within a Docker container and running a GUI application.

The main advantages of using containers are as follows:

• Easy to share development environments as Dockerfiles and Compose files.
• Easy to manage applications and dependent packages together.
• Easy to update and switch application images.
• It is easy to standardize the development and execution environment within the team.
• It is easy to separate the dependencies between the OS itself and applications.

Installing Torizon OS

Writing the OS image

We will install Torizon OS on the Verdin iMX95 (hereinafter referred to as the development board) using Toradex Easy Installer (hereinafter referred to as Tezi).

1. Install the necessary tools on the host PC.

Execute the following command on the host PC.

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sudo apt update
sudo apt install tigervnc-viewer minicom

2. Connect to the target board.

Connect the host PC and the target board using a USB CABLES.
With the target board running Tezi, execute the following command from the host PC:

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vncviewer 192.168.11.1

If a certificate verification screen appears during your initial connection, please review the information before continuing the connection.
The Tezi screen will appear.

If you cannot connect to 192.168.11.1, please check if your USB CABLES supports data communication and if a USB network interface has been created on the host PC.

3. Check the Tezi version

Check the version displayed at the bottom of the Tezi screen.
The Torizon OS image you use must be compatible with the Tezi version.

4. Download the Torizon OS image.

Download the Torizon OS image for Verdin iMX95 from the Toradex download page.

When selecting an image, please check at least the following:

• This is an image for Verdin iMX95.
• Ensure it is compatible with the version of Tezi you are using.
• This article uses Torizon OS 7.7.0 as the testing environment.
• If your Tezi version is older, please select the corresponding image from "Torizon OS 7 older quarterly releases" on the download page.

5. Deploy the OS image to the SD card.

Connect the SD card to the host PC and check the mount point.

In the following example, we assume that the SD card is mounted at /media/$USER/SDCARD.

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tar -xvf torizon-docker-verdin-imx95-Tezi_7.7.0+build.40.tar -C /media/$USER/SDCARD

After extraction, please verify that the image file is located in the root directory of the SD card.

6. Install Torizon OS

Insert the SD card into the target board.

Once the OS images are displayed on the Tezi screen, select the desired image and click "Install" in the upper left corner.

Once the license terms are displayed, review them and click "I Accept".

The OS image writing process will begin.

Once the installation complete screen appears, close VNC Viewer and turn off POWER SUPPLIES to the target board.

This completes the installation of Torizon OS on the Verdin iMX95.

Torizon OS initial setup

After the initial startup, log in using the serial console.

Connect the USB serial conversion CABLES.

Prepare a 1.8V compatible USB serial conversion CABLES.

Connect TX, RX, and GND to the Debug UART on the Mallow carrier board. TX and RX should be cross-connected.

Refer to the hardware documentation for your Mallow carrier board to find the location and pin numbers of the pins to connect.

1. Set serial port Access permissions on the host PC.

Execute the following command on the host PC.

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sudo usermod -aG dialout $USER

After executing the command, please log out and then log back in.

2. Check the serial device.

With the USB serial conversion CABLES connected, check the device file on the host PC.

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ls /dev/ttyUSB0
/dev/ttyUSB0

Depending on your environment, the device name may be displayed as /dev/ttyUSB1 or /dev/ttyACM0. In that case, use the displayed device name in the following commands.

3. Connect to the serial console using minicom

Execute the following command:

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minicom -D /dev/ttyUSB0 115200

Once you've started up minicom, POWER SUPPLIES on the target board.

Wait until the login prompt appears.

4. Log in for the first time.

When the login prompt appears, log in using the following initial credentials.

• Username: torizon
• Initial password: torizon

You will be prompted to change your password upon your first login.
Please enter "torizon" as your current password, then set a new password. Characters will not be displayed on the screen while you are entering your password; this is normal behavior.

To shut down the target board, execute the following command:

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sudo shutdown now

Enabling LVDS DISPLAY

This article uses a Capacitive Touch Display - 10 inch LVDS as DISPLAY for the Verdin iMX95.

In typical embedded Linux development using the Yocto Project, enabling new hardware may require modifying the Device Tree or rebuilding the OS image.

Torizon OS allows you to add settings for DISPLAY and peripheral devices using the Device Tree Overlay.

Since we will be using a Toradex original DISPLAY this time, we will enable the Device Tree Overlay that we have prepared.

sudo tdx-info -dt
Password:

Device tree
------------------------------------------------------------
Device tree enabled:      imx95-verdin-wifi-dev.dtb
Compatible string:        toradex,verdin-imx95-wifi-devtoradex,verdin-imx95-wifitoradex,verdin-imx95fsl,imx95
Device trees available:
                          imx95-verdin-nonwifi-dahlia.dtb
                          imx95-verdin-nonwifi-dev.dtb
                          imx95-verdin-nonwifi-ivy.dtb
                          imx95-verdin-nonwifi-mallow.dtb
                          imx95-verdin-nonwifi-yavia.dtb
                          imx95-verdin-nonwifi-zinnia.dtb
                          imx95-verdin-wifi-dahlia.dtb
                          imx95-verdin-wifi-dev.dtb
                          imx95-verdin-wifi-ivy.dtb
                          imx95-verdin-wifi-mallow.dtb
                          imx95-verdin-wifi-yavia.dtb
                          imx95-verdin-wifi-zinnia.dtb
------------------------------------------------------------

Device tree overlays
------------------------------------------------------------
Overlays enabled:         fdt_overlays=verdin-imx95_dsi-to-hdmi_overlay.dtbo verdin-imx95_spidev_overlay.dtbo
Overlays available:
                          verdin-imx95_dsi-to-hdmi_overlay.dtbo
                          verdin-imx95_dsi-to-lvds_panel-cap-touch-10inch-lvds_overlay.dtbo
                          verdin-imx95_mezzanine_panel-cap-touch-10inch-lvds_overlay.dtbo
                          verdin-imx95_mezzanine_panel-lvds-dual-channel-1080p_overlay.dtbo
                          verdin-imx95_nau8822-btl_overlay.dtbo
                          verdin-imx95_ov5640-27mhz_overlay.dtbo
                          verdin-imx95_ov5640_overlay.dtbo
                          verdin-imx95_panel-cap-touch-10inch-dsi_overlay.dtbo
                          **verdin-imx95_panel-cap-touch-10inch-lvds_overlay.dtbo**
                          verdin-imx95_panel-cap-touch-7inch-dsi_overlay.dtbo
                          verdin-imx95_reserve-cm7-uart_overlay.dtbo
                          verdin-imx95_spidev_overlay.dtbo
------------------------------------------------------------

verdin-imx95_panel-cap-touch-10inch-lvds_overlay.dtbo

sudo tdx-info -dt | grep panel-cap-touch-10inch-lvds

sudo find /sysroot/boot/ostree -path '*/dtb/overlays.txt'

sudo nano /sysroot/boot/ostree/torizon-<deployment-id>/dtb/overlays.txt

- fdt_overlays=verdin-imx95_dsi-to-hdmi_overlay.dtbo verdin-imx95_spidev_overlay.dtbo
+ fdt_overlays=verdin-imx95_panel-cap-touch-10inch-lvds_overlay.dtbo verdin-imx95_spidev_overlay.dtbo

sync
sudo reboot

Setting up a GUI application development environment

From here, we will run a GUI application that uses Python and GTK within a Docker container.

1. Connect the target board to the network.

Connect the network CABLES to the Ethernet port on the target board.

Log in to the target board using a USB serial conversion CABLES.

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minicom -D /dev/ttyUSB0 -b 115200

2. Check the IP address of the target board.

Execute the following command:

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ip addr

In the environment described in this article, ethernet0 was displayed as the wired LAN interface.

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ip addr show ethernet0

An example of the output is shown below.

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5: ethernet0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 00:11:22:33:44:55 brd ff:ff:ff:ff:ff:ff
    altname enP1p0s0f0
    altname end0
    inet 192.168.1.123/24 brd 192.168.1.255 scope global dynamic noprefixroute ethernet0
        valid_lft 63523sec preferred_lft 63523sec

In this example, the IP address of the target board is 192.168.1.123.

In the following commands, please replace the displayed IPv4 address with the actual one.

Depending on your network environment, the interface name may not be ethernet0. In that case, check the output of ip addr to identify the wired LAN interface that is UP and has an IPv4 address assigned to it.

3. Create a working directory on the target board.

Perform the following on the target board:

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mkdir ~/docker/nexty-gui/app
cd docker/nexty-gui

The following steps will be performed on the host PC.

Please save the following files to any directory on your host PC.

• Dockerfile
• build.sh (zip file)
• hello_button.py
• docker-compose.yml
• entrypoint.sh (zip file)

4. Copy the files from the host PC to the target board.

On the host PC's terminal, navigate to the directory where the saved file is located.
Execute the following command to copy the file to the target board.

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scp Dockerfile entrypoint.sh build.sh docker-compose.yml \
torizon@<ターゲットボードのIPアドレス>:/home/torizon/docker/nexty-gui

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scp hello_button.py \
  torizon@<ターゲットボードのIPアドレス>:/home/torizon/docker/nexty-gui/app

Upon initial connection, you may be prompted to verify your SSH host key. Please confirm that the connection destination is correct before proceeding.

If prompted for a password, enter the password you set on the target board.

5. Build the container image.

Return to the target board and grant execute permissions to the copied script file.

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cd ~/docker/nexty-gui
chmod +x build.sh entrypoint.sh

Next, run the build script.

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./build.sh

Container images and packages are downloaded from the network, and a container image for the GUI application is created.

6. Launch the GUI application.

Execute the following command:

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docker compose up

If the GUI application window appears on the LCD, it's a success.

Connect a mouse to the development board and click a button to display a dialog box.

To exit the container, press Ctrl + C in the terminal.

In the docker-compose.yml file, we configure the container to share Wayland SOCKETS and related devices so that GUI applications within the container can Access the target board's display functionality.

Editing the application

For full-fledged application development, you can use the Torizon IDE Extension for Visual Studio Code.

This article introduces a simple method for directly editing Python files within a container and checking the changes.

cd ~/docker/nexty-gui
docker compose run --rm --name nexty-gui-dev \
  -v "$PWD/app:/opt/nexty-gui" \
  nexty-gui bash

ls /opt/nexty-gui

__pycache__  hello_button.py

python3 /opt/nexty-gui/hello_button.py

nano /opt/nexty-gui/hello_button.py

class HelloWindow(Gtk.Window):
    def __init__(self) -> None:
        super().__init__(title="Nexty GUI")
        self.set_default_size(360, 200)
        self.set_border_width(32)

+       box = Gtk.Box(orientation=Gtk.Orientation.VERTICAL, spacing=12)
+       self.add(box)

        button = Gtk.Button(label="押してください")
        button.set_hexpand(True)
        button.set_vexpand(True)
        button.connect("clicked", self.on_clicked)
-       self.add(button)
+       box.pack_start(button, True, True, 0)

+       button2 = Gtk.Button(label="もう一つのボタン")
+       button2.set_hexpand(True)
+       button2.set_vexpand(True)
+       button2.connect("clicked", self.on_clicked)
+       box.pack_start(button2, True, True, 0)

        self.connect("destroy", Gtk.main_quit)

5. Run the modified application.

Execute the following command:

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python3 /opt/nexty-gui/hello_button.py

If two buttons appear, the change was successful.

exit

~/docker/nexty-gui/app/hello_button.py

Summary

This article described the procedure for developing GUI applications on Torizon OS using a Verdin iMX95 SOM and a Mallow carrier board.

The following was covered in this article:

• I installed Torizon OS on a Verdin iMX95.
• Device Tree Overlay for LVDS DISPLAY has been enabled.
• I ran a GUI application using Python and GTK inside a Docker container.
• I edited the application code from within the container using bind mount.
• Rerun the modified application and check the displayed content.

Using Docker containers makes it easier to manage the application's execution environment and dependencies. In embedded Linux development using Torizon OS, separating the OS itself from the application makes it easier to proceed through the development, testing, and operation stages.

ネクスティ エレクトロニクスでは、NXP社のi.MXシリーズを使用した製品開発や技術サポートを行っています。

お客さまの要望に合わせたさまざまな製品のご紹介ができますので、お気軽にお問い合わせください。