Mbed OS Device Management example for various ST boards.


This example application is not maintained and not recommended. It uses an old version of Mbed OS, Pelion DM and Arm toolchain. It doesn't work with Mbed Studio.

Please use: https://os.mbed.com/teams/mbed-os-examples/code/mbed-os-example-pelion/

This example is known to work great on the following platforms:

  • DISCO_L475E_IOT01A - onboard WiFI and onboard QSPI flash. Board specific example using onboard sensors is available here.
  • DISCO_F413H - onboard WiFI and onboard QSPI flash.
  • DISCO_F469NI - WizFi310 WiFI shield and onboard QSPI flash (see WiFi shield instructions).
  • DISCO_F746NG - onboard Ethernet and using onboard QSPI flash.
  • DISCO_F769NI - onboard Ethernet and using onboard QSPI flash.
  • DISCO_L496AG - WizFi310 WiFI shield and onboard QSPI flash (see WiFi shield instructions).
  • NUCLEO_F207ZG - onboard Ethernet and wired SD card (SD card wiring instructions).
  • NUCLEO_F412ZG - WizFi310 WiFI shield and SD card shield (see WiFi shield instructions).
  • NUCLEO_F429ZI - onboard Ethernet and wired SD card (SD card wiring instructions).
  • NUCLEO_F746ZG - onboard Ethernet and wired SD card (SD card wiring instructions).
  • NUCLEO_F767ZI - onboard Ethernet and wired SD card (SD card wiring instructions).
  • NUCLEO_L476RG - WizFi310 WiFI shield and SD card shield (see WiFi shield instructions).
  • NUCLEO_L496ZG - WizFi310 WiFI shield and SD card shield (see WiFi shield instructions).
  • NUCLEO_L4R5ZI - WizFi310 WiFI shield and SD card shield (see WiFi shield instructions).

Follow the Quick-Start instructions: https://cloud.mbed.com/quick-start


Example functionality

This example showcases the following device functionality:

  • Read ADC temperature and ADC vref, and report them as Pelion LWM2M resources (see image below).
  • On user button click, increment Pelion LWM2M button resource.
  • Allow the user to change the state of the board LED from Pelion LWM2M led_state resource and PUT request.


SD card wiring

The ST Nucleo family of boards don't have storage onboard and therefore you will need an SD card. A limitation on ST Nucleo 144 boards is that there's a conflict between Ethernet and SPI pins on Arduino D11. Due to this, the SD card must be wired to different SPI bus that doesn't conflict with other functionality. The image below provide instructions on how to wire an SD card to a non-conflicting SPI instance.


If you are not a first-time Pelion Device Management user your device's SD card may already have connect and update certificates on it. If this is the case, remove and manually format your micro SD card, flash the binary to the device and then re-insert your micro SD card.

WiFi shield setup/wiring

Some ST Nucleo and Discovery boards don't have IP connectivity option, but bundled with a WiFi shield, they can take benefit of full device management capabilities. See links to reference images below on how to wire WizFI310 WiFi shield and/or SD card shield:

Use this example with Mbed CLI

1. Import the application into your desktop:

mbed import /teams/ST/code/pelion-example-common

cd pelion-example-common

2. Install the CLOUD_SDK_API_KEY


For instructions on how to generate your API key, please see the documentation.

3. Initialize firmware credentials (done once per repository). You can use the following command:

mbed dm init -d "<your company name in Pelion DM>" --model-name "<product model identifier>" -q --force

If above command do not work for your Mbed CLI, please consider upgrading Mbed CLI to version 1.8.x or above.

4. Compile and program:

mbed compile -t <toolchain> -m <TARGET_BOARD>

(supported toolchains : GCC_ARM / ARM / IAR)



File content as of revision 23:64f3f756acf6:

// ----------------------------------------------------------------------------
// Copyright 2016-2018 ARM Ltd.
// SPDX-License-Identifier: Apache-2.0
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//     http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.
// ----------------------------------------------------------------------------

#include "mbed.h"
#include "simple-mbed-cloud-client.h"
#include "FATFileSystem.h"
#include "LittleFileSystem.h"

// Default network interface object. Don't forget to change the WiFi SSID/password in mbed_app.json if you're using WiFi.
NetworkInterface *net = NetworkInterface::get_default_instance();

// Default block device available on the target board
BlockDevice *bd = BlockDevice::get_default_instance();

// Use FATFileSystem for SD card type blockdevices
FATFileSystem fs("fs");
// Use LittleFileSystem for non-SD block devices to enable wear leveling and other functions
LittleFileSystem fs("fs");

// Default User button for GET example
InterruptIn button(BUTTON1);
// Default LED to use for PUT/POST example
DigitalOut led(LED1);
// Temperature reading from microcontroller
AnalogIn adc_temp(ADC_TEMP);
// Voltage reference reading from microcontroller
AnalogIn adc_vref(ADC_VREF);


// Declaring pointers for access to Pelion Device Management Client resources outside of main()
MbedCloudClientResource *button_res;
MbedCloudClientResource *led_res;
MbedCloudClientResource *post_res;

MbedCloudClientResource *temp_res;
MbedCloudClientResource *volt_res;

// An event queue is a very useful structure to debounce information between contexts (e.g. ISR and normal threads)
// This is great because things such as network operations are illegal in ISR, so updating a resource in a button's fall() function is not allowed
EventQueue eventQueue;

 * PUT handler - sets the value of the built-in LED
 * @param resource The resource that triggered the callback
 * @param newValue Updated value for the resource
void put_callback(MbedCloudClientResource *resource, m2m::String newValue) {
    printf("PUT received. New value: %s\n", newValue.c_str());
    led = atoi(newValue.c_str());

 * POST handler - prints the content of the payload
 * @param resource The resource that triggered the callback
 * @param buffer If a body was passed to the POST function, this contains the data.
 *               Note that the buffer is deallocated after leaving this function, so copy it if you need it longer.
 * @param size Size of the body
void post_callback(MbedCloudClientResource *resource, const uint8_t *buffer, uint16_t size) {
    printf("POST received (length %u). Payload: ", size);
    for (size_t ix = 0; ix < size; ix++) {
        printf("%02x ", buffer[ix]);

 * Button handler
 * This function will be triggered either by a physical button press or by a ticker every 5 seconds (see below)
void button_press() {
    int v = button_res->get_value_int() + 1;
    printf("Button clicked %d times\n", v);

 * Notification callback handler
 * @param resource The resource that triggered the callback
 * @param status The delivery status of the notification
void button_callback(MbedCloudClientResource *resource, const NoticationDeliveryStatus status) {
    printf("Button notification, status %s (%d)\n", MbedCloudClientResource::delivery_status_to_string(status), status);

 * Registration callback handler
 * @param endpoint Information about the registered endpoint such as the name (so you can find it back in portal)
 * When the device is registered, this variable will be used to access various useful information, like device ID etc.

static const ConnectorClientEndpointInfo* endpointInfo;
void registered(const ConnectorClientEndpointInfo *endpoint) {
    printf("Registered to Pelion Device Management. Endpoint Name: %s\n", endpoint->internal_endpoint_name.c_str());
    endpointInfo = endpoint;

 * Update sensors and report their values.
 * This function is called periodically.
void sensors_update() {
    float temp = adc_temp.read()*100;
    float vref = adc_vref.read();
    printf("ADC temp:  %6.4f C,  vref: %6.4f %%\r\n", temp, vref);
    if (endpointInfo) {

int main(void) {
    printf("\nStarting Simple Pelion Device Management Client example\n");

    int storage_status = fs.mount(bd);
    if (storage_status != 0) {
        printf("Storage mounting failed.\n");

#if USE_BUTTON == 1
    // If the User button is pressed ons start, then format storage.
    bool btn_pressed = (button.read() == MBED_CONF_APP_BUTTON_PRESSED_STATE);
    if (btn_pressed) {
        printf("User button is pushed on start...\n");
    bool btn_pressed = FALSE;
#endif /* USE_BUTTON */

    if (storage_status || btn_pressed) {
        printf("Formatting the storage...\n");
        int storage_status = StorageHelper::format(&fs, bd);
        if (storage_status != 0) {
            printf("ERROR: Failed to reformat the storage (%d).\n", storage_status);
    } else {
        printf("You can hold the user button during boot to format the storage and change the device identity.\n");

    // Connect to the Internet (DHCP is expected to be on)
    printf("Connecting to the network using the default network interface...\n");
    net = NetworkInterface::get_default_instance();

    nsapi_error_t net_status = NSAPI_ERROR_NO_CONNECTION;
    while ((net_status = net->connect()) != NSAPI_ERROR_OK) {
        printf("Unable to connect to network (%d). Retrying...\n", net_status);

    printf("Connected to the network successfully. IP address: %s\n", net->get_ip_address());

    printf("Initializing Pelion Device Management Client...\n");

    // SimpleMbedCloudClient handles registering over LwM2M to Pelion Device Management
    SimpleMbedCloudClient client(net, bd, &fs);
    int client_status = client.init();
    if (client_status != 0) {
        printf("Pelion Client initialization failed (%d)\n", client_status);
        return -1;

    // Creating resources, which can be written or read from the cloud
    button_res = client.create_resource("3200/0/5501", "button_count");

    led_res = client.create_resource("3201/0/5853", "led_state");
    led_res->methods(M2MMethod::GET | M2MMethod::PUT);

    post_res = client.create_resource("3300/0/5605", "execute_function");

    // Sensor resources
    temp_res = client.create_resource("3303/0/5700", "temperature");

    volt_res = client.create_resource("3316/0/5700", "voltage");

    printf("Initialized Pelion Device Management Client. Registering...\n");

    // Callback that fires when registering is complete

    // Register with Pelion DM

    // The button fires on an interrupt context, but debounces it to the eventqueue, so it's safe to do network operations
    printf("Press the user button to increment the LwM2M resource value...\n");

    Ticker timer;
    timer.attach(eventQueue.event(&sensors_update), SENSORS_POLL_INTERVAL);

    // You can easily run the eventQueue in a separate thread if required

#endif /* MBED_TEST_MODE */