pico-node

A Rust firmware for the Raspberry Pi Pico W (RP2040) that brings a packet-radio node to feature parity with the C# node host in m0lte/packet.net, built on the AX.25 v2.2 SDL state machine from m0lte/ax25sdl.

Four capabilities, mirroring the C# node:

1. AXUDP — AX.25-over-UDP, node↔node over WiFi (BPQ-compatible AXIP/AXUDP).
2. KISS-over-TCP — to net-sim (the emulated RF channel) over WiFi.
3. KISS-over-serial — to a NinoTNC, over a direct UART link.
4. Telnet command console over WiFi.

Read first

docs/PLAN.md is the living plan: architecture, the module breakdown mapping to the four capabilities, the SDL integration story, the hands-free dev cycle (build → flash via probe-rs → defmt/RTT logs), the host-side test strategy, the package-approval gate, and the "when the hardware arrives" checklist + blockers.

Layout

• crates/ax25-node-core — portable, no_std-able, zero-dependency logic (KISS, AXUDP, AX.25 codec, CRC, console, SDL glue). Host-tested with cargo test today.
• crates/ax25-node-fw — the thin RP2040 / Embassy firmware binary (standalone, workspace-excluded; built once the embedded toolchain is in place).

Build + test the portable core (works now, offline, no hardware)

cargo test                                                   # host unit tests (default std feature)
cargo build -p ax25-node-core --no-default-features --features alloc   # prove the no_std posture

Build the firmware (requires the toolchain in docs/PLAN.md §8)

cargo build --manifest-path crates/ax25-node-fw/Cargo.toml --release
cargo run   --manifest-path crates/ax25-node-fw/Cargo.toml --release   # flash + stream defmt over SWD