OpenThread CLI onReceive Callback Example

This example demonstrates how to use the OpenThread CLI callback mechanism to capture and process CLI responses asynchronously.
The application shows how to set up a callback function that processes CLI responses line by line, allowing non-blocking CLI interaction.

Supported Targets

Note on Thread Support:

• Thread support must be enabled in the ESP-IDF configuration (CONFIG_OPENTHREAD_ENABLED). This is done automatically when using the ESP32 Arduino OpenThread library.
• This example uses OpenThread.begin() which automatically starts a Thread network with default settings.

Features

• CLI response callback using OpenThreadCLI.onReceive()
• Asynchronous CLI response processing
• Non-blocking CLI command execution
• Demonstrates callback-based CLI interaction pattern
• Automatic Thread network startup with default settings
• Device role monitoring via CLI

Hardware Requirements

• ESP32 compatible development board with Thread support (ESP32-H2, ESP32-C6, or ESP32-C5)
• USB cable for Serial communication

Software Setup

Prerequisites

1. Install the Arduino IDE (2.0 or newer recommended)
2. Install ESP32 Arduino Core with OpenThread support
3. ESP32 Arduino libraries:
   • OpenThread

Configuration

No configuration is required before uploading the sketch. The example automatically starts a Thread network with default settings.

Building and Flashing

1. Open the onReceive.ino sketch in the Arduino IDE.
2. Select your ESP32 board from the Tools > Board menu (ESP32-H2, ESP32-C6, or ESP32-C5).
3. Connect your ESP32 board to your computer via USB.
4. Click the Upload button to compile and flash the sketch.

Expected Output

Once the sketch is running, open the Serial Monitor at a baud rate of 115200. You should see output similar to the following:

OpenThread CLI RESP===> disabled
OpenThread CLI RESP===> disabled
OpenThread CLI RESP===> detached
OpenThread CLI RESP===> child
OpenThread CLI RESP===> router
OpenThread CLI RESP===> router
...

The callback function processes each line of CLI response, showing the device state transitions from "disabled" to "detached" to "child" to "router" (or "leader").

Using the Device

Callback Mechanism

The example demonstrates the callback-based CLI interaction pattern:

1. Callback Registration: OThreadCLI.onReceive(otReceivedLine) registers a callback function
2. Command Execution: OThreadCLI.println("state") sends CLI commands
3. Response Processing: The callback function otReceivedLine() processes responses asynchronously
4. Non-blocking: The main loop continues while CLI responses are processed in the callback

Device State Monitoring

The example continuously monitors the device state:

• Sends "state" command every second
• Callback processes the response
• Shows state transitions as the device joins the Thread network

Customizing the Callback

You can modify the otReceivedLine() function to:

• Parse specific CLI responses
• Extract data from CLI output
• Trigger actions based on CLI responses
• Filter or process specific response patterns

Code Structure

The onReceive example consists of the following main components:

1. otReceivedLine() callback function:

   • Reads all available data from OpenThread CLI
   • Filters out empty lines (EOL sequences)
   • Prints non-empty lines with a prefix

2. setup():

   • Initializes Serial communication
   • Starts OpenThread stack with OpenThread.begin() (auto-start)
   • Initializes OpenThread CLI
   • Registers the callback function using OThreadCLI.onReceive(otReceivedLine)

3. loop():

   • Sends "state" CLI command every second using OThreadCLI.println("state")
   • The callback function processes the response asynchronously
   • Non-blocking operation allows other tasks to run

Troubleshooting

• No callback responses: Ensure the callback is registered in setup. Check that OpenThread CLI is initialized.
• Empty lines in output: The callback filters empty lines, which is normal behavior
• State not changing: Wait for the device to join the Thread network. First device becomes Leader, subsequent devices become Router or Child.
• No serial output: Check baudrate (115200) and USB connection

Related Documentation

• OpenThread CLI Helper Functions API
• OpenThread Core API
• OpenThread Overview

License

This example is licensed under the Apache License, Version 2.0.