Thread: CoAP Server

The Thread CoAP Server sample demonstrates controlling light resources within an OpenThread network. This sample exposes resources in the network and requires another sample that is compatible with the OpenThread network to access them. The recommended sample referenced on this page is Thread: CoAP Client.

Overview

This sample demonstrates how to expose resources that can be accessed by other devices in the same Thread network. You can use this sample application as a starting point to implement a CoAP application.

The following CoAP resources are exposed on the network by this sample:

  • /light - used to control LED 4

  • /provisioning - used to perform provisioning

This sample uses the native OpenThread CoAP API for communication. For new application development, use Zephyr’s CoAP API. For example usage of the Zephyr CoAp API, see the Thread: CoAP Client sample.

Requirements

The sample supports the following development kits:

Hardware platforms

PCA

Board name

Build target

nRF52840 DK

PCA10056

nrf52840dk_nrf52840

nrf52840dk_nrf52840

nRF52833 DK

PCA10010

nrf52833dk_nrf52833

nrf52833dk_nrf52833

You can use one or more of the development kits listed above as the Thread CoAP Server. You also need one or more compatible development kits programmed with the Thread: CoAP Client sample.

User interface

Button 4:

Pressing results in entering the pairing mode for a limited period of time.

LED 1:

On when the OpenThread connection is established.

LED 3:

Blinks when the pairing mode is enabled.

LED 4:

Turned on and off by messages sent from the client nodes.

Building and running

Make sure to enable the OpenThread stack before building and testing this sample. See Working with Thread for more information.

This sample can be found under samples/openthread/coap_server in the nRF Connect SDK folder structure.

See Building and programming a sample application for information about how to build and program the application.

Testing

After building the sample and programming it to your development kit, test it by performing the following steps:

  1. Program at least one development kit with the Thread: CoAP Client sample and reset it.

  2. Turn on the Simple CoAP Client node. This node becomes the Thread network Leader.

  3. Turn on all the other nodes, including the Simple CoAP Server nodes. They enter the network as Children, and will gradually become Routers.

    Note

    It can take up to 15 seconds for Thread to establish network.

  4. Press Button 2 on the client node to control LED 4 on all server nodes.

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

    1. Press Button 4 on a server node to enable pairing.

    2. Press Button 3 on a client node to pair it with the server node in the pairing mode.

  6. Press Button 1 on the client node to control the LED 4 on paired server node.

Running OpenThread CLI commands

You can connect to any of the Simple CoAP Server or Simple CoAP Client nodes through a serial port. For more details, see How to connect with PuTTY.

Note

Thread samples have Hardware Flow Control mechanism enabled by default in serial communication. When enabled, it allows devices to manage transmission by informing each other about their current state, and ensures more reliable connection in high-speed communication scenarios.

Once the serial connection is ready, you can run OpenThread CLI commands. For complete CLI documentation, refer to OpenThread CLI Reference.

Note

In Zephyr shell, every OpenThread command needs to be preceded with the ot keyword. For example, ot channel 20.

Dependencies

This sample uses the following nRF Connect SDK libraries:

In addition, it uses the following Zephyr libraries:

OpenThread CoAP API is used in this sample: