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Thread: CoAP

Overview

The Thread CoAP sample demonstrates how to use OpenThread CoAP API. It can be built to work as a server or as a client.

By running a client and server on two boards, a local Thread network can be created. To create the network, OpenThread uses the network key provided with Kconfig. Once the boards have been flashed, the network will be automatically created and configured.

Once the network is operational, then the client could start interacting with the server. Every time the user presses the button, the LED on server should toggle.

Requirements

Before you start, check that you have the required hardware and software:

  • 2x nRF54L15 Connect Kit with U.FL cabled 2.4 GHz Antenna
  • 2x USB-C Cable
  • A computer running macOS, Ubuntu, or Windows 10 or newer

Attaching the 2.4 GHz antenna

Before applying power to the board, ensure the U.FL cabled 2.4 GHz antenna is properly installed.

Building the sample

To build the sample, follow the instructions in Getting Started Guide to set up your preferred building environment.

Use the following steps to build the Thread CoAP sample on the command line.

  1. Open a terminal window.

  2. Go to NCS-Project/nrf54l15-connectkit repository cloned in the Getting Started Guide.

  3. Build the sample using the west build command, specifying the board (following the -b option) as nrf54l15_connectkit/nrf54l15/cpuapp.

    west build -p always -b nrf54l15_connectkit/nrf54l15/cpuapp samples/openthread/coap -- -DCONFIG_OT_COAP_SAMPLE_SERVER=y

    west build -p always -b nrf54l15_connectkit/nrf54l15/cpuapp samples/openthread/coap

    Tip

    The -p always option forces a pristine build, and is recommended for new users. Users may also use the -p auto option, which will use heuristics to determine if a pristine build is required, such as when building another sample.

  4. After building the sample successfully, the firmware with the name merged.hex can be found in the build directory.

Flashing the firmware

Connect the nRF54L15 Connect Kit to the computer with a USB-C cable:

Then flash the sample using west flash:

west flash

Tip

In case you wonder, the west flash will execute the following command:

pyocd load --target nrf54l --frequency 4000000 build/merged.hex

Testing

After both the server and the client are programmed, complete the following steps to test communication between boards:

  1. Connect to both boards with a terminal emulator, specifying the primary COM port that your computer uses to communicate with the nRF54L15:

    1. Start PuTTY.

    2. Configure the correct serial port and click Open:

    Open up a terminal and run:

    screen <serial-port-name> 115200

    Open up a terminal and run:

    screen <serial-port-name> 115200

  2. Press the DFU/RST button on both boards to reset the nRF54L15.

  3. The Thread network will be automatically created and configured. Invoke some of the OpenThread commands to obtain network-related details from each device:

    Terminal
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    server:~$ ot state
leader
Done
server:~$ ot networkname
OpenThreadDemo
Done
server:~$ ot ipaddr
fdde:ad00:beef:0:0:ff:fe00:fc00
fdde:ad00:beef:0:0:ff:fe00:2800
fdde:ad00:beef:0:7d78:d429:f3e4:3903
fe80:0:0:0:44b8:36d2:4cf7:cc9e
Done
    Terminal
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    client:~$ ot state
router
Done
client:~$ ot networkname
OpenThreadDemo
Done
client:~$ ot ipaddr
fdde:ad00:beef:0:0:ff:fe00:3000
fdde:ad00:beef:0:c53e:ecc0:e981:2524
fe80:0:0:0:88b6:3602:586b:9c37
Done

  4. Press USR button on the client and you should see the Green LED on the server toggling.

  5. The example also provides a shell command to control the LED on the server from the client. To toggle the LED:

    Terminal
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    client:~$ ot_coap led set 0 toggle

  6. You can also get the USR button state on the server from the client:

    Terminal
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    client:~$ ot_coap btn get 0
off
client:~$ ot_coap btn get 0
on

  7. The example uses the broadcast address by default. To control the LED of a specific server, we can use it IPv6 address:

    Terminal
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    client:~$ ot_coap led set 0 toggle fdde:ad00:beef:0:7d78:d429:f3e4:3903