Over-the-air firmware update using MQTT

This code example showcases how to perform an MQTT over-the-air (OTA) update using the CYW955913EVK-01 Evaluation Kit. The device establishes a connection with a specified MQTT broker, which is used as the means of transferring the update. In this example, an AWS MQTT broker is utilized.

The evaluation kit runs an LED blinky task and an OTA agent in the background. The OTA agent allows for remote updates to push to devices, which is a useful feature for IoT applications where physical access to devices is limited. The LED blinky task can continue to run even while an OTA download is happening, meaning that the device can still function normally while updates are taking place.

View this README on GitHub.

Provide feedback on this code example.

Requirements

ModusToolbox™ software v3.2 or later (tested with v3.2) with ModusToolbox™.
Board support package (BSP) minimum required version for : v1.0.0.
Programming language: C
Associated parts: CYW955913EVK-01

Supported toolchains (make variable 'TOOLCHAIN')

GNU Arm® Embedded Compiler v11.3.1 (GCC_ARM) – Default value of TOOLCHAIN

Supported kits (make variable 'TARGET')

CYW955913EVK-01 Wi-Fi Bluetooth® Prototyping Kit (CYW955913EVK-01)

Hardware setup

This example uses the kit’s default configuration. See the respective kit guide to ensure that the kit is configured correctly.

Note: The CYW955913EVK-01 Wi-Fi Bluetooth® Prototyping Kit ships with KitProg3 version 2.30 installed. ModusToolbox™ requires KitProg3 with the latest version 2.50. Before using this code example, make sure that the board is upgraded to KitProg3 version 2.50. The tool and instructions are available in the Firmware Loader GitHub repository. If you do not upgrade, you will see an error like "unable to find CMSIS-DAP device" or "KitProg firmware is out of date".

Software setup

See the ModusToolbox™ tools package installation guide for information about installing and configuring the tools package.

Using the code example

Create the project

The ModusToolbox™ tools package provides the Project Creator as both a GUI tool and a command line tool.

Use Project Creator GUI

Open the Project Creator GUI tool.

There are several ways to do this, including launching it from the dashboard or from inside the Eclipse IDE. For more details, see the Project Creator user guide (locally available at {ModusToolbox™ install directory}/tools_{version}/project-creator/docs/project-creator.pdf).
On the Choose Board Support Package (BSP) page, select a kit supported by this code example. See Supported kits.

Note: To use this code example for a kit not listed here, you may need to update the source files. If the kit does not have the required resources, the application may not work.
On the Select Application page:

a. Select the Applications(s) Root Path and the Target IDE.

Note: Depending on how you open the Project Creator tool, these fields may be pre-selected for you.

b. Select this code example from the list by enabling its check box.

Note: You can narrow the list of displayed examples by typing in the filter box.

c. (Optional) Change the suggested New Application Name and New BSP Name.

d. Click Create to complete the application creation process.

Use Project Creator CLI

The 'project-creator-cli' tool can be used to create applications from a CLI terminal or from within batch files or shell scripts. This tool is available in the {ModusToolbox™ install directory}/tools_{version}/project-creator/ directory.

Use a CLI terminal to invoke the 'project-creator-cli' tool. On Windows, use the command-line 'modus-shell' program provided in the ModusToolbox™ installation instead of a standard Windows command-line application. This shell provides access to all ModusToolbox™ tools. You can access it by typing "modus-shell" in the search box in the Windows menu. In Linux and macOS, you can use any terminal application.

The following example clones the "mtb-example-threadx-wifi-ota-mqtt" application with the desired name "Threadx_wifi_ota_mqtt" configured for the CYW955913EVK-01 BSP into the specified working directory, C:/mtb_projects:

project-creator-cli --board-id CYW955913EVK-01 --app-id mtb-example-threadx-wifi-ota-mqtt --user-app-name Threadx_wifi_ota_mqtt --target-dir "C:/mtb_projects"

The 'project-creator-cli' tool has the following arguments:

Argument	Description	Required/optional
`--board-id`	Defined in the field of the BSP manifest	Required
`--app-id`	Defined in the field of the CE manifest	Required
`--target-dir`	Specify the directory in which the application is to be created if you prefer not to use the default current working directory	Optional
`--user-app-name`	Specify the name of the application if you prefer to have a name other than the example's default name	Optional

Note: The project-creator-cli tool uses the git clone and make getlibs commands to fetch the repository and import the required libraries. For details, see the "Project creator tools" section of the ModusToolbox™ tools package user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mtb_user_guide.pdf).

Open the project

After the project has been created, you can open it in your preferred development environment.

Eclipse IDE

If you opened the Project Creator tool from the included Eclipse IDE, the project will open in Eclipse automatically.

For more details, see the Eclipse IDE for ModusToolbox™ user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mt_ide_user_guide.pdf).

Visual Studio (VS) Code

Launch VS Code manually, and then open the generated {project-name}.code-workspace file located in the project directory.

For more details, see the Visual Studio Code for ModusToolbox™ user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mt_vscode_user_guide.pdf).

Command line

If you prefer to use the CLI, open the appropriate terminal, and navigate to the project directory. On Windows, use the command-line 'modus-shell' program; on Linux and macOS, you can use any terminal application. From there, you can run various make commands.

For more details, see the ModusToolbox™ tools package user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mtb_user_guide.pdf).

Operation

Connect the board to your PC using the provided USB cable through the KitProg3 USB connector.
Configure the following MACROS in ota_app_config.h file:
- Wi-Fi configuration: Modify the WIFI_SSID, WIFI_PASSWORD, and WIFI_SECURITY macros to match with the Wi-Fi network that you want to connect.
- MQTT configuration are as follows:
  
  MQTT_BROKER_URL: Hostname of the MQTT broker
  
  MQTT_SERVER_PORT: Port number for the MQTT connection. As specified by the Internet Assigned Numbers Authority (IANA), port numbers assigned for the MQTT protocol are 1883 for non-secure connections and 8883 for secure connections. However, MQTT brokers can use other ports. Configure this macro as specified by the MQTT broker. (for AWS MQTT broker port number: 8883)
  
  CLIENT_CERTIFICATE and CLIENT_KEY: Certificate and private key of the MQTT client used for client authentication. Note that these macros are applicable only when ENABLE_TLS is set to true.
  
  ROOT_CA_CERTIFICATE: Root CA certificate of the MQTT broker
See the Setting up the MQTT broker section to learn how to configure these macros for AWS IoT MQTT broker.

Save your certificates with the following name in the scripts folder:

 Amazon RootCA file as *amazon_ca.crt*
 Amazon Device certificate as *amazon_client.crt*
 Amazon Device private key as *amazon_private_key.pem*

Edit the job document (/scripts/ota_update.json):

Modify the value of the broker to match the MQTT broker address.

Modify the value of the board to match the kit you are using.

If the code example has been configured to work in non-TLS mode: Set the port value to 1883.
Setup the MQTT publisher script by following Setting up the MQTT publisher subsection under Setting up the MQTT broker section.
Program the board using one of the following:
Using Eclipse IDE
```
      1. Select the application project in the Project Explorer.

      2. In the **Quick Panel**, scroll down, and click **\<Application Name> Program**.
```
In other IDEs

Follow the instructions in your preferred IDE.
Using CLI

From the terminal, execute the make program command to build and program the application using the default toolchain to the default target. The default toolchain is specified in the application's Makefile but you can override this value manually:
```
make program TOOLCHAIN=<toolchain>
```
Example:
```
make program TOOLCHAIN=GCC_ARM
```
The job document placed in the <OTA Application>/scripts/ folder has a value of Version as 1.0.0. Because the OTA application version and the available update version are the same, the update will not happen.
Modify the value of the BLINKY_DELAY_MS macro to (100) in the <OTA Application>/source/led_task.c file and change the app version in the <OTA Application>/Makefile by setting APP_VERSION_MAJOR to '2'.
Build the app (Do not program it to the kit). This new image will be published to the MQTT broker in the following steps to demonstrate the OTA update.

Figure 1. Connection to the MQTT broker
After a successful build, locate the mtb-example-threadx-wifi-ota-mqtt.bin file in the /build//Debug directory. Copy the mtb-example-threadx-wifi-ota-mqtt.bin file to the /scripts directory and rename it to the ota-update.bin file.
Edit the <OTA Application>/scripts/ota_update.json file to modify the value of Version to 2.0.0.
The OTA application now finds the updated Job document, downloads the new image, and places it in the secondary slot. Once the download is complete, issues a soft reset.

Figure 2. Image download
After the image upgrade is successfully complete, observe that the user LED is blinks at 10 Hz.

Debugging

You can debug the example to step through the code.

In Eclipse IDE

Use the <Application Name> Debug (KitProg3_MiniProg4) configuration in the Quick Panel. For details, see the "Program and debug" section in the Eclipse IDE for ModusToolbox™ user guide.

In other IDEs

Follow the instructions in your preferred IDE.

Design and implementation

This example implements two RTOS tasks: OTA client and LED blink. Both these tasks are independent and do not communicate with each other. The OTA client task initializes the dependent middleware and starts the OTA agent. The LED task blinks the user LED at a specified delay.

All the source files related to the two tasks are placed under the <OTA Application>/source/ directory:

File	Description
ota_task.c	Contains the task and functions related to the OTA client.
ota_task.h	Contains the public interfaces for the OTA client task.
led_task.c	Contains the task and functions related to LED blinking.
led_task.h	Contains the public interfaces for the LED blink task.
main.c	Initializes the BSP and the retarget-io library, and creates the OTA client and LED blink tasks.
ota_app_config.h	Contains the OTA and Wi-Fi configuration macros such has SSID, password, MQTT broker details, certificates, and key.

File	Description
publisher.py	Python script to communicate with the client and to publish the OTA images.
ota_update.json	OTA job document.
format_cert_key.py	Python script to convert certificate/key to string format.

Figure 3 shows the flow of the OTA update process using MQTT. The application that needs OTA updates should run the OTA agent. The OTA agent spawns threads to receive OTA updates when available, without intervening with the application's core functionality.

Figure 3. Overview of OTA update using MQTT

Setting up the MQTT broker

AWS IoT MQTT

Set up the MQTT device (also known as a Thing) in the AWS IoT core as described in the Getting started with AWS IoT Core.

Note: While setting up your device, ensure that the policy associated with this device permits all MQTT operations (iot:Connect, iot:Publish, iot:Receive, and iot:Subscribe) for the resource used by this device. For testing purposes, it is recommended to have the following policy document which allows all MQTT Policy Actions on all Amazon Resource Names (ARNs).
```
{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": "iot:*",
            "Resource": "*"
        }
    ]
}
```
In the configs/mqtt_client_config.h file, set MQTT_BROKER_ADDRESS to your custom endpoint on the Settings page of the AWS IoT console. This has the format ABCDEFG1234567.iot.<region>.amazonaws.com.
Set the macros MQTT_PORT to 8883 and MQTT_SECURE_CONNECTION to 1 in the configs/mqtt_client_config.h file.
Download the following certificates and keys that are created and activated in Step 3.
- A certificate for the AWS IoT Thing: xxxxxxxxxx.cert.pem
- A public key: xxxxxxxxxx.public.key
- A private key: xxxxxxxxxx.private.key
- Root CA "RSA 2048 bit key: Amazon Root CA 1 for AWS IoT from CA certificates for server authentication.
Using these certificates and keys, enter the following parameters in the mqtt_client_config.h file in Privacy-Enhanced Mail (PEM) format:
- CLIENT_CERTIFICATE - xxxxxxxxxx.cert.pem
- CLIENT_PRIVATE_KEY - xxxxxxxxxx.private.key
- ROOT_CA_CERTIFICATE - Root CA certificate
You can either convert the values to strings manually following the format shown in mqtt_client_config.h file or you can use the HTML utility available from Infineon GitHub to convert the certificates and keys from PEM format to C string format. Clone the repository from GitHub to use the utility.

Setting up the MQTT publisher script

Open a CLI terminal.

On Linux and macOS, you can use any terminal application. On Windows, open the modus-shell app from the Start menu.
Navigate to the <OTA Application>/scripts/ folder.
Run the following command to ensure that the required Python modules are installed or already present (Requirement already satisfied: is printed on the terminal).
```
pip install -r requirements.txt
```
Edit the <OTA Application>/scripts/publisher.py file and change the value of the variable AMAZON_BROKER_ADDRESS to the MQTT broker address.
Run the publisher.py Python script.

The scripts take arguments such as kit name, broker URL, and file path. For details on the supported arguments and their usage, execute the following command:
```
python publisher.py --help
```
To start the publisher script for the default settings of this example, execute the following command:
```
python publisher.py tls -b amazon
```

Other resources

Infineon provides a wealth of data at www.infineon.com to help you select the right device, and quickly and effectively integrate it into your design.

Related resources

Resources	Links
Device documentation	Contact Infineon Support for device documentation
Development kits	Contact Infineon Support for kit samples
Libraries on GitHub	mtb-pdl-cat5 – CYW55913 Peripheral Driver Library (PDL) mtb-hal-cat5 – Hardware Abstraction Layer (HAL) library retarget-io – Utility library to retarget STDIO messages to a UART port
Tools	ModusToolbox™ – ModusToolbox™ software is a collection of easy-to-use libraries and tools enabling rapid development with Infineon MCUs for applications ranging from wireless and cloud-connected systems, edge AI/ML, embedded sense and control, to wired USB connectivity using PSoC™ Industrial/IoT MCUs, AIROC™ Wi-Fi and Bluetooth® connectivity devices, XMC™ Industrial MCUs, and EZ-USB™/EZ-PD™ wired connectivity controllers. ModusToolbox™ incorporates a comprehensive set of BSPs, HAL, libraries, configuration tools, and provides support for industry-standard IDEs to fast-track your embedded application development.

Other resources

Infineon provides a wealth of data at www.infineon.com to help you select the right device, and quickly and effectively integrate it into your design.

Document history

Document title: CE239613 – Over-the-air firmware update using MQTT

Version	Description of change
1.0.0	New code example

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mtb-example-threadx-wifi-ota-mqtt/README.md

Over-the-air firmware update using MQTT

Requirements

Supported toolchains (make variable 'TOOLCHAIN')

Supported kits (make variable 'TARGET')

Hardware setup

Software setup

Using the code example

Create the project

Open the project

Operation

Debugging

Design and implementation

Setting up the MQTT broker

Other resources

Related resources

Other resources

Document history