knx-pico

A no_std KNXnet/IP protocol implementation for embedded systems, designed for the Embassy async runtime.

Features

• 🚀 no_std compatible - Runs on bare metal embedded systems
• ⚡ Zero-copy parsing - Efficient memory usage for resource-constrained devices
• 🔄 Async/await - Full Embassy async runtime integration
• 🎯 Type-safe addressing - Strong types for Individual and Group addresses
• 🔌 KNXnet/IP tunneling - Reliable point-to-point communication
• 📊 Datapoint Types (DPT) - Support for DPT 1, 3, 5, 7, 9, 13
• 🔍 Gateway auto-discovery - Automatic KNX gateway detection via multicast
• 🛡️ Production-ready - Thoroughly tested with hardware and simulator

Quick Start

Installation

Add to your Cargo.toml:

[dependencies]
knx-pico = "0.1"

Basic Example

use knx_pico::{GroupAddress, protocol::cemi::CemiFrame, dpt::{Dpt1, DptEncode}};

// Create a group address
let light = GroupAddress::new(1, 2, 3)?;

// Encode a boolean value (DPT 1 - Switch)
let value = Dpt1::new(true);
let encoded = value.encode();

// Create a write request frame
let frame = CemiFrame::write_request(light.into(), &encoded)?;

// The frame can now be sent over KNXnet/IP tunnel
// (requires Embassy runtime and network stack - see examples on GitHub)

For complete examples with Embassy runtime and Raspberry Pi Pico 2 W, see the examples directory on GitHub:

• pico_knx_async.rs - Complete working example for Pico 2 W
• knx_sniffer.rs - Interactive testing tool with convenience macros

Hardware Support

Tested Platforms

• ✅ Raspberry Pi Pico 2 W (RP2350) - Primary development platform
• 🔜 ESP32-C3/C6 - Planned support via embassy-esp

Required Hardware

For physical KNX testing:

• Raspberry Pi Pico 2 W (or compatible RP2350 board)
• KNX/IP Gateway (e.g., Gira X1, MDT SCN-IP000.03)
• WiFi network

For testing without hardware: Use the included Python KNX simulator (see Testing).

Architecture

Layer Overview

KNX communication uses three nested protocol layers:

┌─────────────────────────────────────────────────┐
│  KNXnet/IP FRAME (UDP transport)                │
│  ┌───────────────────────────────────────────┐  │
│  │ CEMI (KNX command)                        │  │
│  │  ┌─────────────────────────────────────┐ │  │
│  │  │ DPT (encoded value)                 │ │  │
│  │  │ e.g., true → [0x01]                 │ │  │
│  │  └─────────────────────────────────────┘ │  │
│  └───────────────────────────────────────────┘  │
└─────────────────────────────────────────────────┘

Module Structure

knx-pico/
├── addressing/          # KNX addressing (Individual & Group)
├── protocol/            # KNXnet/IP protocol implementation
│   ├── frame.rs         # Layer 1: KNXnet/IP frames
│   ├── cemi.rs          # Layer 2: CEMI messages
│   ├── services.rs      # Tunneling service builders
│   ├── tunnel.rs        # Typestate tunneling client
│   └── async_tunnel.rs  # Async wrapper for Embassy
├── dpt/                 # Layer 3: Datapoint Types (DPT)
│   ├── dpt1.rs          # Boolean (switches, buttons)
│   ├── dpt3.rs          # 3-bit control (dimming, blinds)
│   ├── dpt5.rs          # 8-bit unsigned (percentage, angle)
│   ├── dpt7.rs          # 16-bit unsigned (counter, brightness)
│   ├── dpt9.rs          # 2-byte float (temperature, humidity)
│   └── dpt13.rs         # 32-bit signed (energy, flow)
├── knx_discovery.rs     # Gateway auto-discovery
├── knx_client.rs        # High-level client API
├── error.rs             # Comprehensive error types
└── lib.rs               # Public API

Convenience Macros

The library provides macros to simplify common operations:

use knx_pico::{ga, knx_write, knx_read, KnxValue};

// Create group addresses with readable notation
let light = ga!(1/2/3);
let temp_sensor = ga!(1/2/10);

// Write values with inline address notation
knx_write!(client, 1/2/3, KnxValue::Bool(true)).await?;
knx_write!(client, 1/2/10, KnxValue::Temperature(21.5)).await?;

// Read values
knx_read!(client, 1/2/10).await?;

// Register multiple DPT types at once
register_dpts! {
    client,
    1/2/3  => Bool,
    1/2/5  => Percent,
    1/2/10 => Temperature,
}?;

Building and Flashing

For Raspberry Pi Pico 2 W

Option 1: USB Logger (Recommended - No probe needed)

# Configure WiFi in src/configuration.rs
# Build and flash in one command
cargo flash-example-usb

# Monitor logs via USB serial
screen /dev/tty.usbmodem* 115200

Option 2: defmt Logger (Requires debug probe)

# Build with defmt-rtt
cargo build --release --example pico_knx_async \
    --target thumbv8m.main-none-eabihf \
    --features embassy-rp

# Flash with probe-rs
probe-rs run --chip RP2350 \
    target/thumbv8m.main-none-eabihf/release/examples/pico_knx_async

Available Commands

See .cargo/config.toml for all commands:

# Examples
cargo flash-example-usb          # Flash pico_knx_async (USB logger)
cargo flash-sniffer-usb-release  # Flash knx_sniffer (USB logger)

# Library checks
cargo check-rp2040              # Check for RP2040 target
cargo test-host-release         # Run host tests (optimized)

# Full verification
./check-all.sh                  # Run all checks

Testing

Without Physical Hardware

Use the included Python KNX simulator for development and testing:

# Start simulator
python3 knx_simulator.py

# Run integration tests
python3 test_runner.py

# Or use Make
make test              # All tests
make test-unit         # Unit tests only

With Physical Hardware

1. Configure WiFi credentials in src/configuration.rs:

   pub const CONFIG: &str = r#"
   WIFI_NETWORK=Your_WiFi_SSID
   WIFI_PASSWORD=Your_WiFi_Password
   "#;
   

2. Flash to hardware:

   cargo flash-example-usb
   

3. Monitor logs:

   screen /dev/tty.usbmodem* 115200
   

See TESTING.md for detailed testing guide.

Gateway Auto-Discovery

The library automatically discovers KNX gateways using multicast SEARCH_REQUEST:

use knx_pico::knx_discovery;
use embassy_time::Duration;

// Discover gateway (3 second timeout)
let gateway = knx_discovery::discover_gateway(&stack, Duration::from_secs(3))
    .await
    .expect("No KNX gateway found");

println!("Found gateway at {}:{}", gateway.ip, gateway.port);

No manual IP configuration needed! See KNX_DISCOVERY.md for details.

Supported Datapoint Types (DPT)

See src/dpt/ for implementation details.

Documentation

• TESTING.md - Testing guide with simulator setup
• KNX_DISCOVERY.md - Gateway discovery details
• PRE_PUBLISH_GUIDE.md - Pre-publish checklist
• examples/README.md - Example documentation
• API Documentation - Full API reference

Project Status

✅ Production Ready

All core features implemented and tested:

• ✅ KNXnet/IP protocol (Frame, CEMI, Services)
• ✅ Datapoint Types (DPT 1, 3, 5, 7, 9, 13)
• ✅ Tunneling client with typestate pattern
• ✅ Embassy + RP2040 integration (Pico 2 W)
• ✅ Gateway auto-discovery via multicast
• ✅ High-level client API with macros
• ✅ Comprehensive testing (unit, integration, hardware)
• ✅ CI/CD automation (GitHub Actions)

Contributing

Contributions are welcome! Please:

1. Fork the repository
2. Create a feature branch
3. Add tests for new functionality
4. Run ./check-all.sh to verify all checks pass
5. Submit a pull request

Performance

Optimized for embedded systems:

• Zero-copy parsing - Minimal memory allocations
• Inline hot paths - Critical functions marked #[inline]
• Unsafe optimizations - Bounds checks eliminated where safe (documented with // SAFETY: comments)
• ~10% performance gain on parsing hot paths
• Fire-and-forget pattern - Optimized command sending for stability

Benchmarked on Raspberry Pi Pico 2 W (RP2350, 150 MHz).

Troubleshooting

Gateway not found during discovery

1. Verify gateway is powered on and connected to network
2. Check that multicast is enabled on your WiFi network
3. Increase discovery timeout to 5 seconds
4. Ensure your WiFi network allows multicast traffic (224.0.23.12)

Connection timeouts

1. Verify gateway IP and port (usually 3671)
2. Check firewall settings (UDP port 3671 must be open)
3. Ensure only one client connects to gateway at a time

Compilation errors

1. Update Rust toolchain: rustup update
2. Install RP2040 target: rustup target add thumbv8m.main-none-eabihf
3. For USB logger: ensure picotool is installed
4. For defmt: ensure probe-rs is installed

See TESTING.md for detailed troubleshooting guide.

License

Licensed under either of:

• Apache License, Version 2.0 (LICENSE-APACHE)
• MIT license (LICENSE-MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.