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Thread CoAP Client

Overview

This section of the documentation explains how to set up a basic OpenThread network composed of the Thread CoAP Client and Server:

  • Thread CoAP Client demonstrates how to use Zephyr CoAP API for communication to access resources available on a Thread server node. The client supports Multiprotocol Bluetooth LE extension which uses the Nordic UART Service (NUS) library to control the LED states over Bluetooth® LE in a Thread network.

  • Thread CoAP Server demonstrates how to expose resources that can be accessed by other devices in the same Thread network. The following CoAP resources are exposed on the network by this sample:

    • /light - used to control Green LED
    • /provisioning - used to perform provisioning

After the Thread network is established, the client node can control the state of Green LED on server nodes. It can turn on the LED either on every server node in the network with a multicast message, or on a single specific server node that is paired with the client node.

Sniffing packets from a Thread network

You can use nRF Sniffer for 802.15.4 to capture and analyze packets exchanged on a Thread network.

Requirements

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

Building the sample

Before you start building, remember to set up the environment first.

Use the following steps to build the samples on the command line.

  1. Open a terminal window.

  2. Go to my-workspace/ncs-playground directory created in the Setting up the environment section.

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    cd my-workspace/ncs-playground

  3. Build each sample using the west command, specifying the board (following the -b option) as connectkit_nrf52840:

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    west build -p always -b connectkit_nrf52840 samples/openthread/coap_client -- -DOVERLAY_CONFIG=overlay-multiprotocol_ble.conf

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    west build -p always -b connectkit_nrf52840 samples/openthread/coap_server

    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 running the west build command, the build files can be found in build/zephyr.

Flashing the firmware

The samples are designed to work with the UF2 Bootloader, so that you can easily flash the sample using the UF2 Bootloader. The firmware can be found in build/zephyr with the name zephyr.uf2.

To flash the firmware, complete the following steps:

  1. Push and hold the USER button and plug your board into the USB port of your computer. Release the USER button after your board is connected. The RGB LED turns green.

  2. It will mount as a Mass Storage Device called UF2BOOT.

  3. Drag and drop zephyr.uf2 onto the UF2BOOT volume. The RGB LED blinks red fast during flashing.

  4. Reset the board and the sample will start running.

  5. Repeat the steps above to flash the client and server board.

Testing

After flashing the firmware to your boards, complete the following steps to test it:

  1. Turn on the board that runs the Thread CoAP Server sample. Wait until the server's RGB LED turns Green. It will create a Thread network and this node becomes the Thread network Leader.
  2. Turn on the board that runs the Thread CoAP Client sample.
  3. Wait until the client's RGB LED turns Green. The client enters the network as a Child, and gradually becomes a Router.
  4. Start the nRF Toolbox app, tap UART to open the UART application.
  5. Connect to the device with the name NUS_CoAP_client discovered in the UART application.

  6. Tap the blank buttons to create new commands. The following command assignments are configured with EOL set to LF :

    • u - Send a unicast CoAP message over Thread.
    • m - Send a multicast CoAP message over Thread.
    • p - Send a pairing request as CoAP message over Thread.

  7. Tap the m command button to send a multicast LIGHT_ON or LIGHT_OFF message (alternatively) to the /light resource. Observe that the Green LED on the server node turns on or off.

  8. Pair a client with a server by completing the following steps:

    1. Press USER button on a server node to enable pairing.
    2. Tap the p command button to pair the client with the server node in the pairing mode.

  9. Tap the u command button to send a unicast LIGHT_TOGGLE message to the /light resource on the paired server node.