Pelion Device Ready example - Cellular Custom

Overview

This is a cellular application to showcase device management capabilities via SK telecom and LGU+. Each telecoms are providing LTE Cat.M1(SKT) and NB-IoT(LGU plus) service in S.Korea.

• For your information; here is mbed-os-example-cellular for BG96(Cat.M1) and TPB23(NB-IoT).

  1. LGU plus with NB-IoT
  2. SKT with Cat.M1

• This codes are based on below versions.

  1. Mbed OS 5.13.1
  2. Mbed-Cloud-Client 2.2.1

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This is a template application to showcase device management capabilities. It demonstrates how to create a simple application that can connect to the Pelion IoT Platform service, register resources and get ready to receive a firmware update.

It's intended to be forked and customized to add platform-specific features (such as sensors and actuators) and configure the connectivity and storage to work out-of-the-box. The template application works in developer mode by default.

There is a mirror version of the stable (master) template application on this location to facilitate the fork and publish on https://os.mbed.com.

Board specific example applications

There are a number of applications that make usage of the Simple Pelion DM Client library.

The Pelion Quick-Start is an initiative to support Mbed Partner's platforms while delivering a great User Experience to Mbed Developers.

In terms of cellular, operation tested with DISCO-L475VG-IOT01A

Getting started with the application

This is a summary of the process for developers to get started and get a device connected to Pelion Device Management.

Using Mbed Online IDE

1. Import the application into the Online IDE.
2. Add the API key to establish connection.
3. Install the developer certificate.
4. Compile and program.

Using Mbed CLI

1. Import the application into your desktop:

   mbed import https://github.com/DanielDmlee/pelion-ready-example.git
   cd pelion-ready-example
   

   • Choose dedicate cellulare configuration:

   cp mbed_app_LGU_NBIoT.json mbed_app.json
   

   or

   cp mbed_app_SKT_CatM1.json mbed_app.json
   

2. Configure the API key for your Pelion Portal account.

   If you don't have an API key available, then login in Pelion IoT Platform portal, navigate to 'Access Management', 'API keys' and create a new one. Then specify the API key as global mbed configuration:

   mbed config -G CLOUD_SDK_API_KEY <your-api-key>
   

3. Install the device management certificate:

   mbed dm init -d "company.com" --model-name "product-model" -q --force
   

4. Compile and program:

   mbed compile -t <toolchain> -m <target> -f
   

Update the application logic

The template example uses a ticker object to periodically fire a software interrupt to simulate button presses. Let’s say you want to make an actual button press.

By default, there is a Ticker object, which fires every five seconds and invokes a callback function:

Ticker timer;
timer.attach(eventQueue.event(&fake_button_press), 5.0);

This callback function changes the button_res resource:

void fake_button_press() {
    int v = button_res->get_value_int() + 1;

    button_res->set_value(v);

    printf("Simulated button clicked %d times\n", v);
}

If you want to change this to an actual button, here is how to do it:

1. Remove:

   Ticker timer;
   timer.attach(eventQueue.event(&fake_button_press), 5.0);

2. Declare an InterruptIn object on the button, and attach the callback function to the fall handler:

   InterruptIn btn(BUTTON1);
   btn.fall(eventQueue.event(&fake_button_press), 5.0);

3. Rename fake_button_press to real_button_press.

Enabling firmware updates

Mbed OS 5.10 and Mbed CLI 1.9 simplifies the process to enable and perform Firmware Updates. Here is a summary on how to configure the device and verify its correct behaviour.

For full documentation about bootloaders and firmware update, read the following documents:

• Introduccion to bootloaders
• Creating and using a bootloader
• Bootloader configuration in Mbed OS
• Mbed Bootloader for Pelion Device Management Client
• Updating devices with Arm Mbed CLI

This is a summary to use Arm Mbed OS managed bootloaders.

Verifying that firmware update works

Follow these steps to generate a manifest, compile and perform a firmware update of your device:

1. Configure the API key for your Pelion account.

   If you don't have an API key available, then login in Pelion IoT Platform portal, navigate to 'Access Management', 'API keys' and create a new one. Then specify the API key as global mbed configuration:

   mbed config -G CLOUD_SDK_API_KEY <your-api-key>
   

2. Initialize the device management feature:

   mbed dm init -d "company.com" --model-name "product-model" -q --force
   

3. Compile the application, include the firware update credentials generated before, merge with the bootloader and program the device:

   mbed compile -t <toolchain> -m <target> -c -f
   

4. Open a serial terminal, verify the application boots and is able to register to the Device Management service. Write down the <endpoint ID>, as it's required to identify the device to perform a firmware update.

5. Update the firmware of the device through Mbed CLI:

   mbed dm update device -D <device ID> -t <toolchain> -m <target>
   

   Inspect the logs on the device to see the update progress. It should look similar to:

   Firmware download requested
   Authorization granted
   Downloading: [+++- ] 6 %
   

   When the download completes, the firmware is verified. If everything is OK, the firmware update is applied, the device reboots and attemps to connect to the Device Management service again. The <endpoint ID> should be preserved.

Automated testing

The Simple Pelion Client provides Greentea tests to confirm your platform works as expected. The network and storage configuration is already defined in Mbed OS 5.10, but you may want to override the configuration in mbed_app.json.

For details on Simple Pelion Client testing, refer to the documentation here.

This template application contains a working application and tests passing for the K64F and K66F platforms.