chore: release v0.5.0

refactor: complete hsmc conversion and add debug-checkpoint feature
Finishes the hsmc migration that was staged across the prior two commits: - Radio task is now a single `machine.run().await`; all I/O lives in state-scoped `during:` activities (`next_command`, `next_packet`, `perform_tx`). The old `push/drain` helpers, the imperative top-level `select`, `handle_cmd`, `handle_rx_result`, and `execute_transmit` are gone. `StartingRx` / `ResumingRx` intermediate states model the host-visible difference between a responding and a silent RX re-arm. - Host/USB task is now an hsmc statechart (Disconnected/Connected) with entry/exit actions handling display wake, radio StopRx, and display reset — replacing the open-coded `was_connected` edge detector. The `protocol_loop` keeps its imperative read path because `read_packet` blocks. - New `debug-checkpoint` cargo feature ships a dedicated `debug_blink.rs` task and a shared atomic counter that code along the boot/dispatch/TX path bumps at notable points. A ladder-latching write policy preserves the deepest TX phase reached on the first attempt until reboot — diagnostic output for UART-only boards where defmt would corrupt the host protocol. Zero footprint when the feature is off. - Silence a stray `clippy::unit_arg` on `led_off` / `led_blip` in the display task for boards with `LedDriver = ()`.
2026-04-16 13:30:52 -06:00 · 2026-04-16 13:28:44 -06:00 · 2026-04-16 13:26:23 -06:00 · 2026-04-16 13:26:04 -06:00 · 2026-04-16 13:25:20 -06:00 · 2026-04-16 13:25:19 -06:00
37 changed files with 5780 additions and 1517 deletions
@@ -11,3 +11,10 @@ rustflags = [
    "-C", "link-arg=-Tdefmt.x",
    "-C", "opt-level=z",
 ]
+
+[target.thumbv6m-none-eabi]
+rustflags = [
+    "-C", "link-arg=-Tlink.x",
+    "-C", "link-arg=-Tdefmt.x",
+    "-C", "opt-level=z",
+]
@@ -5,6 +5,117 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/),
 and this project adheres to [Semantic Versioning](https://semver.org/).

+## [Unreleased]
+
+## [0.5.0] - 2026-04-16
+
+### Added
+
+- BLE soft-mesh multiplexer design document (`BLE_MUX_DESIGN_DOC.md`) —
+  specification for turning a dongle from a 1:1 USB device into a shared
+  near-field radio gateway for multiple BLE-attached phones. Three-phase
+  rollout (v1 MVP, v2 hardening, v3 multi-dongle mesh) with regulatory
+  duty-cycle and TX-access-control enforcement from v1. Targets nRF52840
+  first; ESP32-S3 reserved for v2.
+- `debug-checkpoint` cargo feature with a dedicated `debug_blink` task and
+  a latching atomic checkpoint — LED-pattern diagnostic for UART-only
+  boards where defmt output would corrupt the host protocol. Zero
+  footprint when the feature is off.
+
+### Changed
+
+- Radio task rewritten as an `hsmc` statechart (`Unconfigured` /
+  `Configured.{Idle, StartingRx, Receiving, ResumingRx,
+  Transmitting.{FromIdle, FromRx}}`). The main loop is now a single
+  `machine.run().await`; command reading, packet RX, and TX are
+  state-scoped `during:` activities. Post-TX RX re-arm is modeled as
+  state identity (`TransmittingFromRx` → `ResumingRx`) instead of a
+  `was_receiving` flag.
+- Display task rewritten as an `hsmc` statechart (`Off` /
+  `On.{Splash.{LearnMore, Info}, Dashboard.{Listening, Transmitting}}`).
+  The 5 s splash alternation and 1 s sparkline tick use `on(after …)` /
+  `on(every …)` transitions — no external timer task.
+- USB host task now carries a small `hsmc` statechart (`Disconnected` /
+  `Connected`) whose entry/exit actions handle display wake, radio
+  `StopRx`, and display reset — replacing the open-coded `was_connected`
+  edge detector.
+- Radio → Display channel switched from a `RadioStatus` watch to a typed
+  `RadioEvent` queue. The radio emits discrete `EnteredRx` / `EnteredTx`
+  / `Idle` / `PacketRx` / `PacketTx` / `ConfigChanged` events; downstream
+  consumers observe transitions directly rather than diffing snapshots.
+- Wire protocol types and COBS framing moved out of firmware into the
+  shared `donglora-protocol` crate (path dep on `../protocol`). Firmware
+  `src/protocol.rs` is now a re-export shim preserving every call site;
+  `src/host/framing.rs` keeps only the embassy-specific `route_command`.
+
+### Fixed
+
+- USB disconnect recovery: on a read error the DTR-edge-detect branch
+  now runs unconditionally (was early-continuing in some paths, starving
+  the display-reset / radio-stop handoff).
+
+## [0.4.0] - 2026-04-11
+
+### Added
+
+- ELECROW ThinkNode-M2 board support (ESP32-S3 + SX1262 + 1.3" SH1106 OLED
+  via CP2102 UART bridge, 1000 mAh Li-Po handheld)
+  - Pin map verified against Meshtastic's
+    `variants/esp32s3/ELECROW-ThinkNode-M2`
+  - DIO3 TCXO driven at 3.3 V (not 1.8 V like Heltec)
+  - Dedicated `LORA_POWER_EN` (GPIO48) sequenced HIGH before SPI init
+  - `VEXT_ENABLE` (GPIO46) is active HIGH — opposite polarity from Heltec
+  - Reuses the existing async SH1106 driver at I2C address 0x3C
+
+### Changed
+
+- `hal::esp32s3::{init_spi, init_i2c}` and `board::esp32s3::init_radio` are
+  now generic over GPIO type, so ESP32-S3 boards with different pin
+  assignments can share the helpers.
+- `board::esp32s3::init_radio` takes a `TcxoCtrlVoltage` parameter instead
+  of hardcoding `Ctrl1V8` — needed for ThinkNode-M2's 3.3 V TCXO.
+- SSD1306 display items in `board::esp32s3` are now cfg-gated to Heltec
+  boards (ThinkNode-M2 supplies its own SH1106 `create_display`).
+- `justfile` uses `cargo +esp` for Xtensa targets instead of `cargo +nightly`
+  with a `RUSTC=esp` override — the self-contained esp toolchain keeps its
+  cargo, rustc, and rust-src versions aligned. Public nightly's rust-src
+  had drifted ahead of the esp fork, breaking `-Zbuild-std`.
+- Migrated to embassy-executor 0.10 and embassy-rp 0.10
+- ESP crates (esp-hal, esp-rtos, esp-backtrace, esp-println) patched from
+  esp-rs/esp-hal main branch until esp-rtos publishes with 0.10 support
+- Adapted to embassy-executor 0.10 SpawnToken API (task functions now return
+  `Result<SpawnToken, SpawnError>`, `Spawner::spawn` no longer returns Result)
+- Adapted to esp-hal main branch API changes: `efuse::base_mac_address()`,
+  `esp_rtos::start` now requires `SoftwareInterrupt`, embassy-rp SPI
+  constructor now requires DMA interrupt bindings
+- `just check` now runs clippy with `-D warnings` instead of plain `cargo check`
+- Rust toolchain bumped to 1.94 in mise.toml
+
+### Fixed
+
+- `core::mem::forget(output)` pattern in ESP32-S3 board files is now
+  `let _vext = Output::new(...)` — current esp-hal makes `Output` non-Drop,
+  which made `forget` a no-op and tripped clippy's `forget_non_drop` lint.
+- UART boards (heltec_v3_uart) display stuck on splash screen after boot.
+  Host task sent `DisplayCommand::Reset` (which sets disconnected=true) instead
+  of `DisplayCommand::On`. UART has no DTR, so nothing ever cleared it.
+
+## [0.3.0] - 2026-04-10
+
+### Added
+
+- Waveshare RP2040-LoRa board support (RP2040 + SX1262, no OLED, LED on GPIO25)
+  - First RP2040 board — third MCU family after ESP32-S3 and nRF52840
+  - New `hal/rp2040.rs` module with MCU primitives (SPI, USB, flash unique ID)
+  - USB-C via FPC ribbon cable to adapter board
+  - PE4259 antenna switch on GPIO17, 850-930 MHz (HF)
+
+### Changed
+
+- `cortex-m-rt/set-vtor` moved from global dependency to per-board feature
+  (Cortex-M0+ has no VTOR register)
+- `build.rs` memory.x selection is now target-aware (thumbv6m vs thumbv7em)
+
 ## [0.2.1] - 2026-04-07

 ### Fixed
@@ -72,7 +183,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/).
 - Config validation against per-board hardware limits
 - `TX_POWER_MAX` sentinel (`-128`): auto-use the board's maximum TX power
 - Board support: Heltec V3, Heltec V4, RAK WisBlock 4631
- Python host library (`clients/python/`) with `pip install` and `donglora-mux` CLI
+- Python host library (`donglora` on PyPI) with `pip install` and `donglora-mux` CLI
 - USB multiplexer for sharing one dongle with multiple applications
 - Two-way LoRa bridge over TCP (`examples/lora_bridge.py`)

@@ -3,7 +3,7 @@ members = ["."]

 [package]
 name = "donglora"
-version = "0.2.1"
+version = "0.5.0"
 edition = "2021"
 build = "build.rs"
 authors = ["Stephen Waits <steve@waits.net>"]
@@ -13,10 +13,8 @@ repository = "https://github.com/swaits/donglora"
 keywords = ["lora", "radio", "embedded", "usb", "firmware"]
 categories = ["embedded", "hardware-support", "no-std"]

-# UPGRADE BLOCKED: embassy-executor 0.10 and ucobs 0.3 need Rust >= 1.93
-# stable. The ESP Xtensa toolchain (espup) is a nightly fork that may not
-# support the required language features or pass MSRV gating. Revisit when
-# espup catches up. Check: rustup run esp rustc --version
+# NOTE: esp-rtos patched from GitHub main (see [patch.crates-io] below).
+# Remove patches once esp-rtos publishes with embassy-executor 0.10 support.
 [dependencies]
 cfg-if = "1.0"
 critical-section = "1.2"
@@ -24,14 +22,17 @@ defmt = "1.0"
 embedded-hal = "1.0"
 embedded-hal-async = "1.0"
 embassy-embedded-hal = "0.6"
-embassy-executor = "0.9"
+embassy-executor = "0.10"
 embassy-sync = "0.8"
 embassy-time = "0.5"
 embassy-usb = { version = "0.6", features = ["defmt"] }
 embassy-usb-driver = "0.2"
 ucobs = { version = "0.3", features = ["legacy-msrv"] }
 heapless = "0.9"
+donglora-protocol = { path = "../protocol" }
+hsmc = { path = "../../hsmc/hsmc", default-features = false, features = ["embassy"] }
 lora-phy = "3.0"
+portable-atomic = { version = "1", optional = true, default-features = false, features = ["critical-section"] }
 static_cell = "2.1"

 # Display rendering
@@ -63,8 +64,10 @@ esp-rtos = { version = "0.2", optional = true, features = [
 ] }

 # nRF52840 (RAK 4631)
-cortex-m = { version = "0.7", optional = true, features = ["critical-section-single-core"] }
-cortex-m-rt = { version = "0.7", optional = true, features = ["set-vtor"] }
+cortex-m = { version = "0.7", optional = true, features = [
+  "critical-section-single-core",
+] }
+cortex-m-rt = { version = "0.7", optional = true }
 defmt-rtt = { version = "1.0", optional = true }
 embassy-nrf = { version = "0.10", optional = true, features = [
  "nrf52840",
@@ -74,47 +77,103 @@ embassy-nrf = { version = "0.10", optional = true, features = [
 ] }
 panic-probe = { version = "1.0", optional = true, features = ["print-defmt"] }

+# RP2040 (Waveshare RP2040-LoRa)
+embassy-rp = { version = "0.10", optional = true, features = [
+  "rp2040",
+  "time-driver",
+  "defmt",
+] }
+
 [build-dependencies]
 minijinja = "2.18"
 owo-colors = "4.3"

 [features]
+# The `embassy` feature gates the async-actions codepath inside the `hsmc`
+# statechart macro. Its `#[cfg(feature = "embassy")]` attributes are
+# evaluated in *this* crate's context (a proc-macro cfg quirk), so every
+# board feature must enable it. `tokio` is declared only to silence the
+# macro's `#[cfg(feature = "tokio")]` checks.
+embassy = []
+tokio = []
+# When enabled, replaces the display task with a LED-based diagnostic
+# blinker driven by `crate::debug_blink::CHECKPOINT`. Used for diagnosing
+# the firmware on UART-only boards where defmt output would corrupt the
+# host protocol on the same UART. The LED flashes N times then pauses —
+# a human watches the pattern and reports N to determine where execution
+# reached / stopped.
+debug-checkpoint = []
 heltec_v3 = [
+  "embassy",
  "dep:esp-backtrace",
  "dep:esp-hal",
  "dep:esp-println",
  "dep:esp-rtos",
 ]
 heltec_v3_uart = [
+  "embassy",
  "dep:esp-backtrace",
  "dep:esp-hal",
  "dep:esp-println",
  "dep:esp-rtos",
 ]
 heltec_v4 = [
+  "embassy",
+  "dep:esp-backtrace",
+  "dep:esp-hal",
+  "dep:esp-println",
+  "dep:esp-rtos",
+]
+elecrow_thinknode_m2 = [
+  "embassy",
  "dep:esp-backtrace",
  "dep:esp-hal",
  "dep:esp-println",
  "dep:esp-rtos",
 ]
 rak_wisblock_4631 = [
+  "embassy",
  "dep:cortex-m",
  "dep:cortex-m-rt",
+  "cortex-m-rt/set-vtor",
  "dep:defmt-rtt",
  "dep:embassy-nrf",
  "dep:panic-probe",
-  "embassy-executor/arch-cortex-m",
+  "embassy-executor/platform-cortex-m",
  "embassy-executor/executor-thread",
 ]
 wio_tracker_l1 = [
+  "embassy",
  "dep:cortex-m",
  "dep:cortex-m-rt",
+  "cortex-m-rt/set-vtor",
  "dep:defmt-rtt",
  "dep:embassy-nrf",
  "dep:panic-probe",
-  "embassy-executor/arch-cortex-m",
+  "embassy-executor/platform-cortex-m",
  "embassy-executor/executor-thread",
 ]
+waveshare_rp2040_lora = [
+  "embassy",
+  "dep:cortex-m",
+  "dep:cortex-m-rt",
+  "dep:defmt-rtt",
+  "dep:embassy-rp",
+  "dep:panic-probe",
+  "dep:portable-atomic",
+  "embassy-executor/platform-cortex-m",
+  "embassy-executor/executor-thread",
+]
+
+# REVISIT: esp-rtos 0.2.0 on crates.io pins embassy-executor ^0.9. The
+# esp-rs/esp-hal main branch already supports 0.10. Remove these patches once
+# esp-rtos publishes a release with embassy-executor 0.10 support. Track:
+#   https://github.com/esp-rs/esp-hal/tree/main/esp-rtos
+[patch.crates-io]
+esp-hal       = { git = "https://github.com/esp-rs/esp-hal.git", branch = "main" }
+esp-rtos      = { git = "https://github.com/esp-rs/esp-hal.git", branch = "main" }
+esp-backtrace = { git = "https://github.com/esp-rs/esp-hal.git", branch = "main" }
+esp-println   = { git = "https://github.com/esp-rs/esp-hal.git", branch = "main" }

 [lints.clippy]
 undocumented_unsafe_blocks = "deny"
@@ -122,6 +181,6 @@ undocumented_unsafe_blocks = "deny"
 [profile.release]
 codegen-units = 1
 lto = "fat"
-opt-level = 3  # "s"/"z" break Xtensa (l32r literal range exceeded)
+opt-level = 3     # "s"/"z" break Xtensa (l32r literal range exceeded)
 panic = "abort"
 strip = true
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 Stephen Waits <steve@waits.net>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
@@ -23,7 +23,9 @@ All commands are run from the `firmware/` directory.
 | Heltec V3 | `heltec_v3` | ESP32-S3 | SX1262 | Native CDC-ACM | xtensa-esp32s3-none-elf |
 | Heltec V3 (UART) | `heltec_v3_uart` | ESP32-S3 | SX1262 | CP2102 bridge | xtensa-esp32s3-none-elf |
 | Heltec V4 | `heltec_v4` | ESP32-S3 | SX1262 | Native CDC-ACM | xtensa-esp32s3-none-elf |
+| ELECROW ThinkNode-M2 | `elecrow_thinknode_m2` | ESP32-S3 | SX1262 | CP2102 bridge | xtensa-esp32s3-none-elf |
 | RAK WisBlock 4631 | `rak_wisblock_4631` | nRF52840 | SX1262 | Native CDC-ACM | thumbv7em-none-eabihf |
+| Waveshare RP2040-LoRa | `waveshare_rp2040_lora` | RP2040 | SX1262 | Native CDC-ACM | thumbv6m-none-eabi |
 | Wio Tracker L1 | `wio_tracker_l1` | nRF52840 | SX1262 | Native CDC-ACM | thumbv7em-none-eabihf |

 ### Heltec V3 USB Note
@@ -108,14 +108,19 @@ fn main() {
    println!("cargo:rerun-if-changed=src/board/mod.rs.j2");
    println!("cargo:rerun-if-changed={}", board_dir);

-    // cortex-m-rt's link.x does `INCLUDE memory.x`. Copy our nRF layout into
-    // OUT_DIR so it's only visible to ARM builds.
+    // cortex-m-rt's link.x does `INCLUDE memory.x`. Copy the correct layout
+    // into OUT_DIR based on the target MCU family.
    let target = std::env::var("TARGET").unwrap_or_default();
-    if !target.starts_with("xtensa") {
+    let memory_x = match target.as_str() {
+        "thumbv7em-none-eabihf" => Some("ld/nrf52840-memory.x"),
+        "thumbv6m-none-eabi" => Some("ld/rp2040-memory.x"),
+        _ => None,
+    };
+    if let Some(src) = memory_x {
        let out_dir = std::env::var("OUT_DIR").unwrap();
-        fs::copy("ld/nrf52840-memory.x", format!("{out_dir}/memory.x"))
-            .expect("failed to copy ld/nrf52840-memory.x");
+        fs::copy(src, format!("{out_dir}/memory.x")).expect("failed to copy memory.x");
        println!("cargo:rustc-link-search={out_dir}");
    }
    println!("cargo:rerun-if-changed=ld/nrf52840-memory.x");
+    println!("cargo:rerun-if-changed=ld/rp2040-memory.x");
 }
@@ -1,19 +1,24 @@
 set shell := ["bash", "-c"]

 # Board definitions: feature target chip
-# Xtensa targets use nightly cargo + esp rustc + -Zbuild-std=core.
+# Xtensa targets use the self-contained esp toolchain (espup-installed) with
+# `-Zbuild-std=core,alloc`. Using `+esp` rather than `+nightly` keeps the
+# compiler and rust-src versions aligned — the public nightly drifts ahead of
+# the esp fork and breaks core-stdlib compilation otherwise.
 # Tool versions are pinned in mise.toml; run `just setup` to install everything.
 heltec_v3      := "heltec_v3 xtensa-esp32s3-none-elf esp32s3"
 heltec_v3_uart := "heltec_v3_uart xtensa-esp32s3-none-elf esp32s3"
 heltec_v4      := "heltec_v4 xtensa-esp32s3-none-elf esp32s3"
+elecrow_thinknode_m2 := "elecrow_thinknode_m2 xtensa-esp32s3-none-elf esp32s3"
 rak_wisblock_4631  := "rak_wisblock_4631 thumbv7em-none-eabihf nRF52840_xxAA"
 wio_tracker_l1     := "wio_tracker_l1 thumbv7em-none-eabihf nRF52840_xxAA"
+waveshare_rp2040_lora := "waveshare_rp2040_lora thumbv6m-none-eabi rp2040"

 builds_dir := "builds"
 version := `sed -n 's/^version = "\(.*\)"/\1/p' Cargo.toml`

 # All known boards
-boards := "heltec_v3 heltec_v3_uart heltec_v4 rak_wisblock_4631 wio_tracker_l1"
+boards := "heltec_v3 heltec_v3_uart heltec_v4 elecrow_thinknode_m2 rak_wisblock_4631 waveshare_rp2040_lora wio_tracker_l1"

 # Install all required tools and toolchains
 setup:
@@ -28,7 +33,8 @@ setup:
    @if ! rustup component list --toolchain nightly --installed 2>/dev/null | grep -q "^rust-src"; then \
        rustup component add rust-src --toolchain nightly; \
    fi
-    @# ARM target
+    @# ARM targets
+    @rustup target list --installed | grep -q "^thumbv6m-none-eabi$" || rustup target add thumbv6m-none-eabi
    @rustup target list --installed | grep -q "^thumbv7em-none-eabihf$" || rustup target add thumbv7em-none-eabihf

 # Build release firmware for all boards, installing toolchains as needed
@@ -55,12 +61,8 @@ check-all:
        fi; \
    done

-# Check a single board compiles
+# Check a single board compiles (clippy with warnings as errors)
 check board:
-    @just _cargo {{board}} "check --release"
-
-# Run clippy on a single board
-clippy board:
    @just _cargo {{board}} "clippy --release" "-- -D warnings"

 # Build release firmware and copy to builds/ with a readable name
@@ -103,10 +105,7 @@ test:

 # Check for outdated dependencies
 outdated:
-    @# embassy-executor 0.10 renamed arch-* → platform-* features.
-    @# esp-rtos 0.2 still pins embassy-executor ^0.9, blocking the upgrade.
-    @# cargo-outdated crashes trying to resolve 0.10 with the old feature name.
-    cargo outdated --exclude embassy-executor
+    cargo outdated

 # ── Private helpers ───────────────────────────────────────────────────

@@ -116,18 +115,18 @@ _ensure_tools:
    @mise trust --yes . 2>/dev/null; mise install --quiet

 # Run a cargo command for a board.
-# Xtensa: nightly cargo + esp rustc (via RUSTC override) + -Zbuild-std=core
+# Xtensa: esp toolchain (cargo + rustc + rust-src together) + -Zbuild-std=core
 [private]
 _cargo board cmd extra_args="":
    @just _ensure_tools
    @read -r feat target chip <<< "$(just _info {{board}})"; \
-    env=""; extra=""; \
+    extra=""; buildstd=""; \
    case "$target" in xtensa-*) \
        just _require_esp_toolchain; \
        [ -f "$HOME/export-esp.sh" ] && . "$HOME/export-esp.sh"; \
-        env="RUSTC=$(rustup which rustc --toolchain esp)"; extra="+nightly"; buildstd="-Zbuild-std=core,alloc";; \
+        extra="+esp"; buildstd="-Zbuild-std=core,alloc";; \
    esac; \
-    eval $env cargo $extra {{cmd}} --target "$target" --features "$feat" $buildstd {{extra_args}}
+    cargo $extra {{cmd}} --target "$target" --features "$feat" $buildstd {{extra_args}}

 # Ensure a board's toolchain is available, auto-installing if needed
 [private]
@@ -138,17 +137,15 @@ _can_build board:
        *) rustup target list --installed | grep -q "^$target$" || rustup target add "$target" ;; \
    esac

-# Ensure the ESP Xtensa toolchain is installed (espup installed via mise)
+# Ensure the ESP Xtensa toolchain is installed (espup installed via mise).
+# The esp toolchain ships with its own cargo, rustc, and rust-src — no extra
+# components are needed on top.
 [private]
 _require_esp_toolchain:
    @just _ensure_tools
    @if ! rustup toolchain list | grep -q "^esp"; then \
        echo "ESP toolchain not found, installing via espup (this may take a while)..." >&2; \
        espup install || { echo "error: espup install failed" >&2; exit 1; }; \
-    fi; \
-    if ! rustup component list --toolchain nightly --installed 2>/dev/null | grep -q "^rust-src"; then \
-        echo "Installing nightly rust-src (needed for -Zbuild-std)..." >&2; \
-        rustup component add rust-src --toolchain nightly || { echo "error: failed to install rust-src" >&2; exit 1; }; \
    fi

 # Find a serial port matching any of the given VID:PID pairs (checked in order)
@@ -176,6 +173,16 @@ _copy_firmware board profile:
    if [ -f "$src" ]; then \
        cp "$src" "$dst.elf"; echo "→ $dst.elf"; \
        case "$target" in \
+            xtensa-*) \
+                mise exec -- espflash save-image --chip "$chip" --merge --skip-padding "$src" "$dst.bin"; \
+                echo "→ $dst.bin"; \
+                ;; \
+            thumbv6m-*) \
+                mise exec -- rust-objcopy -O ihex "$src" "$dst.hex"; \
+                mise exec -- cargo-hex-to-uf2 hex-to-uf2 --input-path "$dst.hex" --output-path "$dst.uf2" --family rp2040; \
+                rm "$dst.hex"; \
+                echo "→ $dst.uf2"; \
+                ;; \
            thumbv7em-*) \
                mise exec -- rust-objcopy -O ihex "$src" "$dst.hex"; \
                mise exec -- cargo-hex-to-uf2 hex-to-uf2 --input-path "$dst.hex" --output-path "$dst.uf2" --family nrf52840; \
@@ -206,6 +213,8 @@ _info name:
    @if [ "{{name}}" == "heltec_v3" ]; then echo "{{heltec_v3}}"; \
     elif [ "{{name}}" == "heltec_v3_uart" ]; then echo "{{heltec_v3_uart}}"; \
     elif [ "{{name}}" == "heltec_v4" ]; then echo "{{heltec_v4}}"; \
+     elif [ "{{name}}" == "elecrow_thinknode_m2" ]; then echo "{{elecrow_thinknode_m2}}"; \
     elif [ "{{name}}" == "rak_wisblock_4631" ]; then echo "{{rak_wisblock_4631}}"; \
+     elif [ "{{name}}" == "waveshare_rp2040_lora" ]; then echo "{{waveshare_rp2040_lora}}"; \
     elif [ "{{name}}" == "wio_tracker_l1" ]; then echo "{{wio_tracker_l1}}"; \
     else echo "Unknown board: {{name}}" >&2; exit 1; fi
@@ -0,0 +1,24 @@
+/* RP2040 memory layout — UF2 bootloader (ROM boot2)
+ *
+ *   0x10000000 – 0x10000100   boot2 (second-stage bootloader, 256 bytes)
+ *   0x10000100 – 0x10200000   Application  <- we live here
+ *
+ * Flash: 2MB (W25Q16JV on Waveshare RP2040-LoRa)
+ * RAM: 264KB SRAM (two 256KB banks + 2x 4KB scratch)
+ */
+
+MEMORY
+{
+  BOOT2 : ORIGIN = 0x10000000, LENGTH = 0x100
+  FLASH : ORIGIN = 0x10000100, LENGTH = 2048K - 0x100
+  RAM   : ORIGIN = 0x20000000, LENGTH = 264K
+}
+
+EXTERN(BOOT2_FIRMWARE)
+
+SECTIONS {
+    .boot2 ORIGIN(BOOT2) :
+    {
+        KEEP(*(.boot2));
+    } > BOOT2
+} INSERT BEFORE .text;
@@ -1,5 +1,5 @@
 [tools]
-rust = "1.93"
+rust = "1.94"
 just = "latest"

 "cargo:cargo-binutils" = "latest"   # `cargo size`, `cargo objdump`, etc.
@@ -7,6 +7,7 @@
 Create `src/board/your_board.rs`. Use an existing board as a template:
 - ESP32-S3 boards: copy `heltec_v4.rs` (uses shared helpers from `board/esp32s3.rs` and `hal/esp32s3.rs`)
 - nRF52840 boards: copy `rak_wisblock_4631.rs` (uses shared helpers from `hal/nrf52840.rs`)
+- RP2040 boards: copy `waveshare_rp2040_lora.rs` (uses shared helpers from `hal/rp2040.rs`)
 - New MCU family: create a new `hal/<mcu>.rs` with MCU primitives first

 `build.rs` auto-discovers your board file — any `.rs` file in `src/board/` that
@@ -0,0 +1,141 @@
+//! ELECROW ThinkNode-M2 — ESP32-S3 Meshtastic handset with SH1106 OLED.
+//!
+//! Tamagotchi-form-factor handheld: ESP32-S3-WROOM-1-N4 + SX1262 + 1.3" SH1106
+//! OLED + CP2102 UART bridge + 1000 mAh Li-Po. Sold pre-loaded with Meshtastic;
+//! this firmware turns it into a DongLoRa radio bridge.
+//!
+//! Pin map (verified from Meshtastic's variants/esp32s3/ELECROW-ThinkNode-M2
+//! and PR meshtastic/firmware#6354):
+//!   LoRa SPI: SCK=12, MOSI=11, MISO=13, CS=10
+//!   LoRa ctl: RESET=21, BUSY=14, DIO1=3
+//!   LoRa pwr: GPIO48 (must be HIGH before any SPI traffic)
+//!   OLED:     I2C0 SDA=16, SCL=15, SH1106 @ 0x3C
+//!   VEXT:     GPIO46 (active HIGH — gates OLED supply)
+//!   UART:     TX=43, RX=44 via CP2102 bridge
+//!   LED:      GPIO6 (active HIGH indicator)
+//!
+//! Notable differences from the Heltec ESP32-S3 boards:
+//!   * Display is SH1106 (not SSD1306) — uses the existing sh1106 driver.
+//!   * VEXT_ENABLE polarity is reversed (active HIGH here, active LOW on Heltec).
+//!   * Dedicated LoRa power enable on GPIO48 — must be sequenced before SPI init.
+//!   * TCXO is driven at 3.3 V via DIO3 (Heltec uses 1.8 V).
+
+use esp_hal::gpio::{Level, Output, OutputConfig};
+
+use super::esp32s3;
+use super::traits::{BoardParts, LoRaBoard};
+use crate::driver::sh1106::Sh1106;
+use crate::driver::simple_led::SimpleLed;
+use crate::hal::esp32s3 as mcu;
+
+pub use super::esp32s3::{DisplayI2c, RadioDriver, RadioParts};
+
+// ── Concrete peripheral types ───────────────────────────────────────
+
+pub type DisplayDriver = Sh1106<DisplayI2c>;
+pub type UartDriver = esp_hal::uart::Uart<'static, esp_hal::Async>;
+pub type LedDriver = SimpleLed<Output<'static>>;
+
+// ── Peripheral bundles ──────────────────────────────────────────────
+
+pub struct UartParts {
+    pub driver: UartDriver,
+}
+
+pub struct DisplayParts {
+    pub i2c: DisplayI2c,
+}
+
+// ── Display init ────────────────────────────────────────────────────
+
+pub async fn create_display(i2c: DisplayI2c) -> Option<DisplayDriver> {
+    let mut display = Sh1106::new(i2c, 0x3C);
+
+    embassy_time::Timer::after_millis(100).await;
+    if display.init().await.is_err() {
+        defmt::error!("SH1106 display init failed");
+        return None;
+    }
+    let _ = display.set_brightness(0xFF).await;
+    Some(display)
+}
+
+// ── Board init ──────────────────────────────────────────────────────
+
+pub struct Board {
+    p: esp_hal::peripherals::Peripherals,
+}
+
+impl LoRaBoard for Board {
+    const NAME: &'static str = "ELECROW ThinkNode-M2";
+    const TX_POWER_RANGE: (i8, i8) = (-9, 22);
+
+    type RadioParts = RadioParts;
+    type CommParts = UartParts;
+    type DisplayParts = DisplayParts;
+    type DisplayDriver = DisplayDriver;
+    type LedDriver = LedDriver;
+
+    fn init() -> Self {
+        let p = esp_hal::init(esp_hal::Config::default());
+        Self { p }
+    }
+
+    fn mac_address() -> [u8; 6] {
+        mcu::mac_address()
+    }
+
+    fn into_parts(self) -> BoardParts<RadioParts, UartParts, DisplayParts, LedDriver> {
+        let p = self.p;
+
+        mcu::start_timer(p.TIMG0, p.SW_INTERRUPT);
+
+        // VEXT_ENABLE: GPIO46, active HIGH — powers OLED rail (opposite of Heltec).
+        // Output has no Drop impl, so the pin stays HIGH for program lifetime.
+        let _vext = Output::new(p.GPIO46, Level::High, OutputConfig::default());
+        esp_hal::delay::Delay::new().delay_millis(10);
+
+        // LORA_POWER_EN: GPIO48, active HIGH — must be HIGH before any SPI traffic.
+        let _lora_pwr = Output::new(p.GPIO48, Level::High, OutputConfig::default());
+        esp_hal::delay::Delay::new().delay_millis(10);
+
+        // SPI2 for SX1262: SCK=12, MOSI=11, MISO=13
+        let spi_bus = mcu::init_spi(p.SPI2, p.DMA_CH0, p.GPIO12, p.GPIO11, p.GPIO13);
+
+        // SX1262: CS=10, RESET=21, DIO1=3, BUSY=14, TCXO driven at 3.3 V via DIO3.
+        let radio = esp32s3::init_radio(
+            spi_bus,
+            p.GPIO10,
+            p.GPIO21,
+            p.GPIO3,
+            p.GPIO14,
+            lora_phy::sx126x::TcxoCtrlVoltage::Ctrl3V3,
+        );
+
+        // UART0 via CP2102 bridge: TX=43, RX=44
+        use esp_hal::uart::{Config as UartConfig, Uart};
+        let host = UartParts {
+            driver: Uart::new(p.UART0, UartConfig::default())
+                .expect("UART init")
+                .with_tx(p.GPIO43)
+                .with_rx(p.GPIO44)
+                .into_async(),
+        };
+
+        // I2C0 for SH1106 OLED: SDA=16, SCL=15
+        let i2c = mcu::init_i2c(p.I2C0, p.GPIO16, p.GPIO15);
+        let display = Some(DisplayParts { i2c });
+
+        // LED on GPIO6 (active HIGH)
+        let led_pin = Output::new(p.GPIO6, Level::Low, OutputConfig::default());
+        let led = SimpleLed(led_pin);
+
+        BoardParts {
+            radio,
+            host,
+            display,
+            led,
+            mac: Self::mac_address(),
+        }
+    }
+}
@@ -7,7 +7,7 @@
 use embassy_embedded_hal::shared_bus::asynch::spi::SpiDevice;
 use embassy_sync::blocking_mutex::raw::NoopRawMutex;
 use embassy_time::Delay;
-use esp_hal::gpio::{Input, InputConfig, Level, Output, OutputConfig, Pull};
+use esp_hal::gpio::{Input, InputConfig, InputPin, Level, Output, OutputConfig, OutputPin, Pull};

 use lora_phy::iv::GenericSx126xInterfaceVariant;
 use lora_phy::sx126x::{self, Sx1262, Sx126x};
@@ -32,12 +32,25 @@ pub struct RadioParts {
    pub delay: Delay,
 }

+// SSD1306 display support is Heltec-specific. ESP32-S3 boards that use a
+// different controller (e.g. ThinkNode-M2 uses SH1106) provide their own
+// DisplayParts / DisplayDriver / create_display directly.
+#[cfg(any(
+    feature = "heltec_v3",
+    feature = "heltec_v3_uart",
+    feature = "heltec_v4"
+))]
 pub struct DisplayParts {
    pub i2c: DisplayI2c,
 }

 // ── Display driver ──────────────────────────────────────────────────

+#[cfg(any(
+    feature = "heltec_v3",
+    feature = "heltec_v3_uart",
+    feature = "heltec_v4"
+))]
 pub type DisplayDriver = ssd1306::Ssd1306Async<
    ssd1306::prelude::I2CInterface<DisplayI2c>,
    ssd1306::size::DisplaySize128x64,
@@ -45,6 +58,11 @@ pub type DisplayDriver = ssd1306::Ssd1306Async<
 >;

 /// Construct and initialize an SSD1306 display from raw I2C.
+#[cfg(any(
+    feature = "heltec_v3",
+    feature = "heltec_v3_uart",
+    feature = "heltec_v4"
+))]
 pub async fn create_display(i2c: DisplayI2c) -> Option<DisplayDriver> {
    use ssd1306::mode::DisplayConfigAsync;
    use ssd1306::prelude::{Brightness, DisplayRotation};
@@ -67,12 +85,17 @@ pub async fn create_display(i2c: DisplayI2c) -> Option<DisplayDriver> {
 // ── Shared peripheral init helpers ──────────────────────────────────

 /// Construct SX1262 radio from an initialized SPI bus.
+///
+/// Generic over GPIO type so boards with different radio pin assignments can
+/// share this helper. `tcxo_voltage` selects the DIO3-driven TCXO supply:
+/// Heltec boards use `Ctrl1V8`, the ELECROW ThinkNode-M2 uses `Ctrl3V3`, etc.
 pub fn init_radio(
    spi_bus: &'static embassy_sync::mutex::Mutex<NoopRawMutex, SpiBus>,
-    nss_pin: esp_hal::peripherals::GPIO8<'static>,
-    reset_pin: esp_hal::peripherals::GPIO12<'static>,
-    dio1_pin: esp_hal::peripherals::GPIO14<'static>,
-    busy_pin: esp_hal::peripherals::GPIO13<'static>,
+    nss_pin: impl OutputPin + 'static,
+    reset_pin: impl OutputPin + 'static,
+    dio1_pin: impl InputPin + 'static,
+    busy_pin: impl InputPin + 'static,
+    tcxo_voltage: sx126x::TcxoCtrlVoltage,
 ) -> RadioParts {
    let nss = Output::new(nss_pin, Level::High, OutputConfig::default());
    let spi_device = SpiDevice::new(spi_bus, nss);
@@ -86,7 +109,7 @@ pub fn init_radio(

    let sx_config = sx126x::Config {
        chip: Sx1262,
-        tcxo_ctrl: Some(sx126x::TcxoCtrlVoltage::Ctrl1V8),
+        tcxo_ctrl: Some(tcxo_voltage),
        use_dcdc: true,
        rx_boost: false,
    };
@@ -14,9 +14,7 @@ use super::traits::{BoardParts, LoRaBoard};
 use crate::driver::simple_led::SimpleLed;
 use crate::hal::esp32s3 as mcu;

-pub use super::esp32s3::{
-    create_display, DisplayDriver, DisplayParts, RadioDriver, RadioParts,
-};
+pub use super::esp32s3::{create_display, DisplayDriver, DisplayParts, RadioDriver, RadioParts};

 pub type UsbDriver = esp_hal::otg_fs::asynch::Driver<'static>;
 pub type LedDriver = SimpleLed<Output<'static>>;
@@ -51,14 +49,21 @@ impl LoRaBoard for Board {
    fn into_parts(self) -> BoardParts<RadioParts, UsbParts, DisplayParts, LedDriver> {
        let p = self.p;

-        mcu::start_timer(p.TIMG0);
+        mcu::start_timer(p.TIMG0, p.SW_INTERRUPT);

-        // Vext power: GPIO36, active LOW to enable peripherals
-        let vext = Output::new(p.GPIO36, Level::Low, OutputConfig::default());
-        core::mem::forget(vext);
+        // Vext power: GPIO36, active LOW to enable peripherals.
+        // Output has no Drop impl, so the pin stays configured for program lifetime.
+        let _vext = Output::new(p.GPIO36, Level::Low, OutputConfig::default());

        let spi_bus = mcu::init_spi(p.SPI2, p.DMA_CH0, p.GPIO9, p.GPIO10, p.GPIO11);
-        let radio = esp32s3::init_radio(spi_bus, p.GPIO8, p.GPIO12, p.GPIO14, p.GPIO13);
+        let radio = esp32s3::init_radio(
+            spi_bus,
+            p.GPIO8,
+            p.GPIO12,
+            p.GPIO14,
+            p.GPIO13,
+            lora_phy::sx126x::TcxoCtrlVoltage::Ctrl1V8,
+        );

        // Note: switches internal USB PHY from Serial-JTAG to OTG.
        let usb_inst = esp_hal::otg_fs::Usb::new(p.USB0, p.GPIO20, p.GPIO19);
@@ -72,12 +77,12 @@ impl LoRaBoard for Board {
            ),
        };

-        // SSD1306 display reset: pulse GPIO21 low->high before I2C init
+        // SSD1306 display reset: pulse GPIO21 low->high before I2C init.
+        // Output has no Drop impl; pin stays HIGH after this block.
        let mut display_rst = Output::new(p.GPIO21, Level::Low, OutputConfig::default());
        esp_hal::delay::Delay::new().delay_millis(10);
        display_rst.set_high();
        esp_hal::delay::Delay::new().delay_millis(10);
-        core::mem::forget(display_rst);

        let i2c = mcu::init_i2c(p.I2C0, p.GPIO17, p.GPIO18);
        let display = Some(DisplayParts { i2c });
@@ -13,9 +13,7 @@ use super::traits::{BoardParts, LoRaBoard};
 use crate::driver::simple_led::SimpleLed;
 use crate::hal::esp32s3 as mcu;

-pub use super::esp32s3::{
-    create_display, DisplayDriver, DisplayParts, RadioDriver, RadioParts,
-};
+pub use super::esp32s3::{create_display, DisplayDriver, DisplayParts, RadioDriver, RadioParts};

 pub type UartDriver = esp_hal::uart::Uart<'static, esp_hal::Async>;
 pub type LedDriver = SimpleLed<Output<'static>>;
@@ -50,14 +48,21 @@ impl LoRaBoard for Board {
    fn into_parts(self) -> BoardParts<RadioParts, UartParts, DisplayParts, LedDriver> {
        let p = self.p;

-        mcu::start_timer(p.TIMG0);
+        mcu::start_timer(p.TIMG0, p.SW_INTERRUPT);

-        // Vext power: GPIO36, active LOW to enable peripherals
-        let vext = Output::new(p.GPIO36, Level::Low, OutputConfig::default());
-        core::mem::forget(vext);
+        // Vext power: GPIO36, active LOW to enable peripherals.
+        // Output has no Drop impl, so the pin stays configured for program lifetime.
+        let _vext = Output::new(p.GPIO36, Level::Low, OutputConfig::default());

        let spi_bus = mcu::init_spi(p.SPI2, p.DMA_CH0, p.GPIO9, p.GPIO10, p.GPIO11);
-        let radio = esp32s3::init_radio(spi_bus, p.GPIO8, p.GPIO12, p.GPIO14, p.GPIO13);
+        let radio = esp32s3::init_radio(
+            spi_bus,
+            p.GPIO8,
+            p.GPIO12,
+            p.GPIO14,
+            p.GPIO13,
+            lora_phy::sx126x::TcxoCtrlVoltage::Ctrl1V8,
+        );

        use esp_hal::uart::{Config as UartConfig, Uart};
        let host = UartParts {
@@ -68,12 +73,12 @@ impl LoRaBoard for Board {
                .into_async(),
        };

-        // SSD1306 display reset: pulse GPIO21 low->high before I2C init
+        // SSD1306 display reset: pulse GPIO21 low->high before I2C init.
+        // Output has no Drop impl; pin stays HIGH after this block.
        let mut display_rst = Output::new(p.GPIO21, Level::Low, OutputConfig::default());
        esp_hal::delay::Delay::new().delay_millis(10);
        display_rst.set_high();
        esp_hal::delay::Delay::new().delay_millis(10);
-        core::mem::forget(display_rst);

        let i2c = mcu::init_i2c(p.I2C0, p.GPIO17, p.GPIO18);
        let display = Some(DisplayParts { i2c });
@@ -6,9 +6,7 @@ use super::traits::{BoardParts, LoRaBoard};
 use crate::driver::simple_led::SimpleLed;
 use crate::hal::esp32s3 as mcu;

-pub use super::esp32s3::{
-    create_display, DisplayDriver, DisplayParts, RadioDriver, RadioParts,
-};
+pub use super::esp32s3::{create_display, DisplayDriver, DisplayParts, RadioDriver, RadioParts};

 pub type UsbDriver = esp_hal::otg_fs::asynch::Driver<'static>;

@@ -44,14 +42,21 @@ impl LoRaBoard for Board {
    fn into_parts(self) -> BoardParts<RadioParts, UsbParts, DisplayParts, LedDriver> {
        let p = self.p;

-        mcu::start_timer(p.TIMG0);
+        mcu::start_timer(p.TIMG0, p.SW_INTERRUPT);

-        // Vext power: GPIO36, active LOW to enable peripherals
-        let vext = Output::new(p.GPIO36, Level::Low, OutputConfig::default());
-        core::mem::forget(vext);
+        // Vext power: GPIO36, active LOW to enable peripherals.
+        // Output has no Drop impl, so the pin stays configured for program lifetime.
+        let _vext = Output::new(p.GPIO36, Level::Low, OutputConfig::default());

        let spi_bus = mcu::init_spi(p.SPI2, p.DMA_CH0, p.GPIO9, p.GPIO10, p.GPIO11);
-        let radio = esp32s3::init_radio(spi_bus, p.GPIO8, p.GPIO12, p.GPIO14, p.GPIO13);
+        let radio = esp32s3::init_radio(
+            spi_bus,
+            p.GPIO8,
+            p.GPIO12,
+            p.GPIO14,
+            p.GPIO13,
+            lora_phy::sx126x::TcxoCtrlVoltage::Ctrl1V8,
+        );

        // Note: switches internal USB PHY from Serial-JTAG to OTG.
        let usb_inst = esp_hal::otg_fs::Usb::new(p.USB0, p.GPIO20, p.GPIO19);
@@ -65,12 +70,12 @@ impl LoRaBoard for Board {
            ),
        };

-        // SSD1315 display reset: pulse GPIO21 low->high before I2C init
+        // SSD1315 display reset: pulse GPIO21 low->high before I2C init.
+        // Output has no Drop impl; pin stays HIGH after this block.
        let mut display_rst = Output::new(p.GPIO21, Level::Low, OutputConfig::default());
        esp_hal::delay::Delay::new().delay_millis(10);
        display_rst.set_high();
        esp_hal::delay::Delay::new().delay_millis(10);
-        core::mem::forget(display_rst);

        let i2c = mcu::init_i2c(p.I2C0, p.GPIO17, p.GPIO18);
        let display = Some(DisplayParts { i2c });
@@ -129,7 +129,12 @@ impl LoRaBoard for Board {
        // ── Display (optional RAK1921 SSD1306 OLED on I2C) ─────
        let twim_buf = mcu::alloc_i2c_buffer();
        let i2c = embassy_nrf::twim::Twim::new(
-            p.TWISPI0, mcu::Irqs, p.P0_13, p.P0_14, twim::Config::default(), twim_buf,
+            p.TWISPI0,
+            mcu::Irqs,
+            p.P0_13,
+            p.P0_14,
+            twim::Config::default(),
+            twim_buf,
        );
        let display = Some(DisplayParts { i2c });

@@ -48,7 +48,9 @@ pub trait LoRaBoard: Sized {
    fn mac_address() -> [u8; 6];

    /// Decompose initialized board into peripheral bundles for each task.
-    fn into_parts(self) -> BoardParts<Self::RadioParts, Self::CommParts, Self::DisplayParts, Self::LedDriver>;
+    fn into_parts(
+        self,
+    ) -> BoardParts<Self::RadioParts, Self::CommParts, Self::DisplayParts, Self::LedDriver>;
 }

 /// Peripheral bundles for each firmware task, produced by [`LoRaBoard::into_parts`].
@@ -0,0 +1,150 @@
+use embassy_embedded_hal::shared_bus::asynch::spi::SpiDevice;
+use embassy_rp::gpio::{Input, Level, Output, Pull};
+use embassy_rp::spi;
+use embassy_sync::blocking_mutex::raw::NoopRawMutex;
+use embassy_time::Delay;
+
+use lora_phy::iv::GenericSx126xInterfaceVariant;
+use lora_phy::sx126x::{self, Sx1262, Sx126x};
+
+use super::traits::{BoardParts, LoRaBoard};
+use crate::hal::rp2040 as mcu;
+
+// ── Concrete peripheral types ──────────────────────────────────────
+
+type Nss = Output<'static>;
+type Iv = GenericSx126xInterfaceVariant<Output<'static>, Input<'static>>;
+type RadioSpiDevice = SpiDevice<'static, NoopRawMutex, mcu::SpiBus, Nss>;
+pub type RadioDriver = Sx126x<RadioSpiDevice, Iv, Sx1262>;
+pub type UsbDriver = mcu::UsbRpDriver;
+pub type LedDriver = crate::driver::simple_led::SimpleLed<Output<'static>>;
+
+// Display types — never instantiated (no OLED on this board), but the
+// trait requires concrete associated types that satisfy the bounds.
+pub type DisplayI2c =
+    embassy_rp::i2c::I2c<'static, embassy_rp::peripherals::I2C0, embassy_rp::i2c::Async>;
+pub type DisplayDriver = ssd1306::Ssd1306Async<
+    ssd1306::prelude::I2CInterface<DisplayI2c>,
+    ssd1306::size::DisplaySize128x64,
+    ssd1306::mode::BufferedGraphicsModeAsync<ssd1306::size::DisplaySize128x64>,
+>;
+
+// ── Peripheral bundles ─────────────────────────────────────────────
+
+pub struct RadioParts {
+    pub driver: RadioDriver,
+    pub delay: Delay,
+}
+
+pub struct UsbParts {
+    pub driver: UsbDriver,
+}
+
+pub struct DisplayParts {
+    pub i2c: DisplayI2c,
+}
+
+// ── Display init ───────────────────────────────────────────────────
+
+pub async fn create_display(_i2c: DisplayI2c) -> Option<DisplayDriver> {
+    None
+}
+
+// ── Board init ─────────────────────────────────────────────────────
+
+pub struct Board {
+    p: embassy_rp::Peripherals,
+}
+
+impl LoRaBoard for Board {
+    const NAME: &'static str = "Waveshare RP2040-LoRa";
+    const TX_POWER_RANGE: (i8, i8) = (-9, 22);
+
+    type RadioParts = RadioParts;
+    type CommParts = UsbParts;
+    type DisplayParts = DisplayParts;
+    type DisplayDriver = DisplayDriver;
+    type LedDriver = LedDriver;
+
+    fn init() -> Self {
+        let p = embassy_rp::init(Default::default());
+        Self { p }
+    }
+
+    fn mac_address() -> [u8; 6] {
+        mcu::mac_address()
+    }
+
+    fn into_parts(self) -> BoardParts<RadioParts, UsbParts, DisplayParts, LedDriver> {
+        let p = self.p;
+
+        // ── MAC address from flash unique ID ───────────────────
+        let mut flash =
+            embassy_rp::flash::Flash::<_, _, { 2 * 1024 * 1024 }>::new_blocking(p.FLASH);
+        mcu::init_mac(&mut flash);
+
+        // ── SPI1 bus for SX1262 ────────────────────────────────
+        //
+        // Pin mapping from Meshtastic & MeshCore firmware (confirmed working):
+        //   SCK = GPIO14, MOSI = GPIO15, MISO = GPIO24, CS = GPIO13
+        //
+        // The Waveshare wiki (https://www.waveshare.com/wiki/RP2040-LoRa) lists
+        // different pins (MOSI=11, MISO=8, CS=9) but those don't work in practice.
+        // Both sets are valid SPI1 alternate functions on RP2040.
+        let mut spi_cfg = spi::Config::default();
+        spi_cfg.frequency = 1_000_000;
+        let spi = spi::Spi::new(
+            p.SPI1,
+            p.PIN_14,
+            p.PIN_15,
+            p.PIN_24,
+            p.DMA_CH0,
+            p.DMA_CH1,
+            mcu::Irqs,
+            spi_cfg,
+        );
+        let spi_bus = mcu::share_spi_bus(spi);
+
+        let nss = Output::new(p.PIN_13, Level::High);
+        let spi_device = SpiDevice::new(spi_bus, nss);
+
+        let reset = Output::new(p.PIN_23, Level::High);
+        let dio1 = Input::new(p.PIN_16, Pull::Down);
+        let busy = Input::new(p.PIN_18, Pull::Down);
+
+        // PE4259 antenna switch: GPIO17 = !CTRL (rx_enable).
+        // DIO2 is internally wired as CTRL (tx_enable), managed by the SX1262.
+        let rx_enable = Output::new(p.PIN_17, Level::Low);
+        let iv = GenericSx126xInterfaceVariant::new(reset, dio1, busy, Some(rx_enable), None)
+            .expect("SX1262 interface init");
+
+        let sx_config = sx126x::Config {
+            chip: Sx1262,
+            tcxo_ctrl: None, // No TCXO on this board
+            use_dcdc: true,
+            rx_boost: false,
+        };
+
+        let radio = RadioParts {
+            driver: Sx126x::new(spi_device, iv, sx_config),
+            delay: Delay,
+        };
+
+        // ── USB ────────────────────────────────────────────────
+        let host = UsbParts {
+            driver: embassy_rp::usb::Driver::new(p.USB, mcu::Irqs),
+        };
+
+        // ── LED on GPIO25 ──────────────────────────────────────
+        let led_pin = Output::new(p.PIN_25, Level::Low);
+        let led = crate::driver::simple_led::SimpleLed(led_pin);
+
+        BoardParts {
+            radio,
+            host,
+            display: None,
+            led,
+            mac: Self::mac_address(),
+        }
+    }
+}
@@ -128,7 +128,12 @@ impl LoRaBoard for Board {
        // ── Display (SH1106 OLED on I2C) ────────────────────────
        let twim_buf = mcu::alloc_i2c_buffer();
        let i2c = embassy_nrf::twim::Twim::new(
-            p.TWISPI0, mcu::Irqs, p.P0_06, p.P0_05, twim::Config::default(), twim_buf,
+            p.TWISPI0,
+            mcu::Irqs,
+            p.P0_06,
+            p.P0_05,
+            twim::Config::default(),
+            twim_buf,
        );
        let display = Some(DisplayParts { i2c });

@@ -1,14 +1,12 @@
 //! Inter-task communication channels.
 //!
-//! Each channel connects exactly two tasks:
 //! - [`CommandChannel`]: USB → Radio (host commands)
 //! - [`ResponseChannel`]: Radio → USB (firmware responses)
 //! - [`DisplayCommandChannel`]: USB → Display (on/off/reset)
-//! - [`StatusWatch`]: Radio → Display (observable radio state)
+//! - [`RadioEventChannel`]: Radio → Display (typed events from the radio)

 use embassy_sync::blocking_mutex::raw::CriticalSectionRawMutex;
 use embassy_sync::channel::Channel;
-use embassy_sync::watch::Watch;

 use crate::protocol::{Command, RadioConfig, Response};

@@ -17,6 +15,7 @@ use crate::protocol::{Command, RadioConfig, Response};
 pub enum DisplayCommand {
    On,
    Off,
+    #[allow(dead_code)] // only used by USB host task, not UART
    Reset,
 }

@@ -29,39 +28,27 @@ pub type CommandChannel = Channel<CriticalSectionRawMutex, Command, 16>;
 /// Radio-to-host response channel (depth 32: buffer RX packets while USB writes).
 pub type ResponseChannel = Channel<CriticalSectionRawMutex, Response, 32>;

-/// Observable radio status for the display task (2 receivers max).
-/// Display always sees the latest state — intermediate updates may be
-/// skipped, which is fine for a status display.
-pub type StatusWatch = Watch<CriticalSectionRawMutex, RadioStatus, 2>;
-
-/// Current radio state exposed to observers (e.g. display).
+/// Radio → downstream typed events. The radio task emits one of these at
+/// every mode transition and every RF packet. Mode events and data events
+/// are separate: `EnteredRx` / `EnteredTx` / `Idle` describe what the radio
+/// is *doing now*, while `PacketRx` / `PacketTx` describe *what just
+/// happened* without implying a mode change.
 #[derive(Debug, Clone, defmt::Format)]
-pub struct RadioStatus {
-    pub state: RadioState,
-    pub config: Option<RadioConfig>,
-    pub rx_count: u32,
-    pub tx_count: u32,
-    pub last_rssi: Option<i16>,
-    pub last_snr: Option<i16>,
-}
-
-/// Radio state machine states.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, defmt::Format)]
-pub enum RadioState {
+pub enum RadioEvent {
+    /// Radio is now in RX mode.
+    EnteredRx,
+    /// Radio is now in TX mode.
+    EnteredTx,
+    /// Radio is now idle.
    Idle,
-    Receiving,
-    Transmitting,
+    /// A packet was received with these link metrics.
+    PacketRx { rssi: i16, snr: Option<i16> },
+    /// A packet was transmitted successfully.
+    PacketTx,
+    /// `SetConfig` applied a new validated config.
+    ConfigChanged(RadioConfig),
 }

-impl Default for RadioStatus {
-    fn default() -> Self {
-        Self {
-            state: RadioState::Idle,
-            config: None,
-            rx_count: 0,
-            tx_count: 0,
-            last_rssi: None,
-            last_snr: None,
-        }
-    }
-}
+/// Radio → Display event stream (depth 32: buffer RX bursts while the
+/// display drains slowly).
+pub type RadioEventChannel = Channel<CriticalSectionRawMutex, RadioEvent, 32>;
@@ -0,0 +1,229 @@
+//! LED-based diagnostic blinker (opt-in via the `debug-checkpoint` cargo
+//! feature).
+//!
+//! On boards whose UART is also the host protocol (heltec_v3_uart, any
+//! UART-only variant), defmt output would corrupt the COBS-framed host
+//! protocol. We can't use `defmt::info!` for live debugging on those
+//! boards while the host is connected. Instead we expose a single global
+//! atomic checkpoint; code sets it at interesting points in the boot /
+//! dispatch flow, and a dedicated task continuously flashes the board
+//! LED N times, pauses, and repeats — so a human can count the flashes
+//! and report "it got to N."
+//!
+//! Blink pattern:
+//! * Each flash: 400 ms ON, 400 ms OFF.
+//! * After N flashes: 2000 ms pause (LED held OFF).
+//! * Repeat indefinitely with the current `CHECKPOINT` value.
+//!
+//! Usage:
+//! ```ignore
+//! #[cfg(feature = "debug-checkpoint")]
+//! crate::debug_blink::set(3);  // "we reached checkpoint 3"
+//! ```
+//!
+//! The task replaces `display_task` when the `debug-checkpoint` feature is
+//! enabled — it takes the board LED and drives it exclusively.
+//!
+//! # Current checkpoint map
+//!
+//! Defined by the `crate::radio` module. Updated here any time the
+//! numbering changes there.
+//!
+//! | Flashes | Meaning                                                |
+//! |--------:|--------------------------------------------------------|
+//! |   1     | `radio_task` entered (pre-`LoRa::new`)                  |
+//! |   2     | `LoRa::new` succeeded                                   |
+//! |   3     | Machine constructed; about to enter `run()`             |
+//! |   4     | In `Idle` state                                         |
+//! |   5     | In `Receiving` state                                    |
+//! |   6     | TX phase 1: entered `perform_tx` (engages latch)        |
+//! |   7     | TX phase 2: in CAD                                      |
+//! |   8     | TX phase 3: in `prepare_for_tx`                         |
+//! |   9     | TX phase 4: awaiting `tx()`                             |
+//! |  10     | TX phase 5: `do_tx` returned OK                         |
+//! |  11     | TX phase 6: `respond_tx_done` handler entered           |
+//! |  12     | TX phase 7: `responses.send(TxDone)` returned           |
+//! |  13     | TX phase 8: `host_task` received the response from chan |
+//! |  14     | TX phase 9: `host_task` wrote response bytes to UART — TERMINAL SUCCESS |
+//! |  15     | TX errored somewhere — TERMINAL ERROR                   |
+//! |  16     | Boot error: `LoRa::new` failed                          |
+//! |  17     | Boot error: `start_rx` failed inside `start_rx_hw`      |
+//!
+//! # Latching
+//!
+//! * Latch engages **only** on `set(6)` (entry to `perform_tx`).
+//! * While latched, only TX-phase values (6–15) can update `CHECKPOINT`,
+//!   and only if strictly deeper than the current value.
+//! * Terminals (14 success, 15 error) freeze the latch until reboot.
+//! * `set(13)` and `set(14)` called from `host_task` are **no-ops before
+//!   the latch engages** — this prevents unrelated SetConfig/Ok responses
+//!   from polluting the display before any TX has happened.
+//!
+//! # Diagnostic logic
+//!
+//! If ai-bot reports a timeout but the LED shows:
+//! * **10** → `do_tx` ok, but `TransmitDone` event never dispatched.
+//! * **11** → handler entered, but `responses.send(...)` hung.
+//! * **12** → send pushed to channel, but `host_task` never picked it up.
+//! * **13** → `host_task` picked it up, but `tx.write_all` to UART hung.
+//! * **14** → full end-to-end firmware success. Hang is on the host side
+//!   of the UART (mux or wire).
+//! * **15** → TX errored somewhere along the way.
+//!
+//! # Building with the feature
+//!
+//! The `just` build/flash recipes pass a fixed feature list and don't
+//! surface an `extra-features` argument. To build a debug image:
+//!
+//! ```sh
+//! cd firmware
+//! . ~/export-esp.sh   # if building for xtensa (esp32s3)
+//! cargo +esp build --release \
+//!     --target xtensa-esp32s3-none-elf \
+//!     --features heltec_v3_uart,debug-checkpoint \
+//!     -Zbuild-std=core,alloc
+//! cp target/xtensa-esp32s3-none-elf/release/donglora \
+//!    builds/donglora-heltec_v3_uart-v$(sed -n 's/^version = "\(.*\)"/\1/p' \
+//!    Cargo.toml).elf
+//! espflash flash -p /dev/ttyUSB0 builds/donglora-heltec_v3_uart-v0.4.0.elf
+//! ```
+//!
+//! The normal `just flash heltec_v3_uart` command builds without the
+//! feature, so the debug code has zero footprint on release firmware.
+
+use core::sync::atomic::{AtomicBool, AtomicU8, Ordering};
+
+use embassy_executor::task;
+use embassy_time::{Duration, Timer};
+
+use crate::board::{LedDriver, RgbLed};
+
+/// Current diagnostic checkpoint — read by the blinker task. Zero means
+/// "no checkpoint set yet."
+///
+/// Write policy (see [`set`]): once a TX-phase value (6, 11, 12, 13) is
+/// stored, the latch engages and:
+/// * subsequent TX-phase writes update the value only if strictly deeper,
+/// * non-TX-phase writes (including the 7/10 terminal markers and the
+///   steady-state 4/5 post-TX writes) are **ignored** so the deepest phase
+///   reached on the FIRST TX attempt persists.
+///
+/// Rationale: a stuck-then-recovered TX attempt would normally flicker
+/// through the display too quickly to count. Latching preserves the
+/// evidence until reboot.
+pub static CHECKPOINT: AtomicU8 = AtomicU8::new(0);
+
+/// Has the TX-phase latch engaged yet? Written by [`set`], checked by
+/// [`set`]. Not intended for external inspection.
+static HAS_LATCHED: AtomicBool = AtomicBool::new(false);
+
+#[inline]
+fn is_host_phase(n: u8) -> bool {
+    // Values set only from `host_task` — meaningless before a TX has
+    // started, so we refuse to overwrite with them when the latch is
+    // not yet engaged.
+    n == 13 || n == 14
+}
+
+/// Ordered depth of each TX-related checkpoint. Returns `0` for values
+/// that are NOT TX phases (e.g. boot / steady-state / error indicators).
+///
+/// Value 18 ("next_command received CmdTransmit") is intentionally the
+/// SHALLOWEST TX phase — it fires before `perform_tx` entry (value 6)
+/// but is numerically higher because it was added last. The latch uses
+/// `phase_depth` rather than raw numeric comparison so 18 can engage
+/// the latch at depth 1 and later TX phases (6..=15) deepen over it.
+#[inline]
+fn phase_depth(n: u8) -> u8 {
+    match n {
+        18 => 1,  // pre-TX: CmdTransmit just read from commands channel
+        6 => 2,   // perform_tx entered
+        7 => 3,   // in CAD
+        8 => 4,   // in prepare_for_tx
+        9 => 5,   // in tx().await
+        10 => 6,  // do_tx returned Ok
+        11 => 7,  // respond_tx_done entered
+        12 => 8,  // respond_tx_done: responses.send returned
+        13 => 9,  // host_task received response from channel
+        14 => 10, // host_task wrote response to UART (terminal success)
+        15 => 11, // TX errored (terminal error)
+        _ => 0,   // not a TX phase
+    }
+}
+
+#[inline]
+fn is_tx_phase(n: u8) -> bool {
+    phase_depth(n) > 0
+}
+
+#[inline]
+fn is_tx_terminal(n: u8) -> bool {
+    n == 14 || n == 15
+}
+
+/// Record that we reached checkpoint `n`. A no-op in terms of visible
+/// behavior unless the blinker task is spawned; the store itself is very
+/// cheap so leaving these calls in non-debug builds is harmless.
+///
+/// Latch semantics:
+/// * `set(18)` (CmdTransmit received by `next_command`) or `set(6)`
+///   (entry to `perform_tx`) engage the latch.
+/// * While latched, only strictly-deeper TX phases (by `phase_depth`)
+///   update the checkpoint.
+/// * Terminal values (14 success, 15 error) freeze the latch until
+///   reboot.
+/// * Host-phase values (13, 14) called from `host_task` are ignored
+///   before the latch engages, so unrelated `Response::Ok` writes from
+///   SetConfig don't pollute the LED reading before any TX.
+#[inline]
+pub fn set(n: u8) {
+    if HAS_LATCHED.load(Ordering::Relaxed) {
+        let cur = CHECKPOINT.load(Ordering::Relaxed);
+        if is_tx_terminal(cur) {
+            return;
+        }
+        if phase_depth(n) > phase_depth(cur) {
+            CHECKPOINT.store(n, Ordering::Relaxed);
+        }
+        return;
+    }
+
+    // Latch not yet engaged.
+    if is_host_phase(n) {
+        // `host_task` is draining the response channel before any TX —
+        // these values would be misleading. Skip them.
+        return;
+    }
+
+    CHECKPOINT.store(n, Ordering::Relaxed);
+    if is_tx_phase(n) {
+        HAS_LATCHED.store(true, Ordering::Relaxed);
+    }
+}
+
+/// Dedicated task that continuously flashes the LED to show the current
+/// checkpoint. Owns the board's LED driver exclusively — on boards where
+/// the display task would normally own the LED for RX/TX blips, spawn
+/// *either* this task *or* `display_task`, not both.
+#[task]
+pub async fn debug_blink_task(mut led: LedDriver) {
+    // Start with the LED off so the first flash is unambiguous.
+    led.set_rgb(0, 0, 0).await;
+
+    loop {
+        let n = CHECKPOINT.load(Ordering::Relaxed);
+        if n == 0 {
+            // No checkpoint yet — wait and re-check.
+            Timer::after(Duration::from_millis(200)).await;
+            continue;
+        }
+        for _ in 0..n {
+            led.set_rgb(255, 255, 255).await;
+            Timer::after(Duration::from_millis(400)).await;
+            led.set_rgb(0, 0, 0).await;
+            Timer::after(Duration::from_millis(400)).await;
+        }
+        // Long pause to separate cycles so the human can count.
+        Timer::after(Duration::from_millis(2000)).await;
+    }
+}
@@ -1,5 +1,12 @@
-#[cfg(feature = "wio_tracker_l1")]
+#[cfg(any(feature = "wio_tracker_l1", feature = "elecrow_thinknode_m2"))]
 pub mod sh1106;

-#[cfg(any(feature = "heltec_v3", feature = "heltec_v3_uart", feature = "heltec_v4", feature = "wio_tracker_l1"))]
+#[cfg(any(
+    feature = "heltec_v3",
+    feature = "heltec_v3_uart",
+    feature = "heltec_v4",
+    feature = "elecrow_thinknode_m2",
+    feature = "wio_tracker_l1",
+    feature = "waveshare_rp2040_lora"
+))]
 pub mod simple_led;
@@ -73,9 +73,9 @@ impl<I: I2c> Sh1106<I> {
        for page in 0..PAGES {
            // Set page address and column start (with SH1106 2-column offset).
            self.cmd(&[
-                0xB0 | page as u8,          // page address
-                COL_OFFSET & 0x0F, // column low nibble
-                0x10 | (COL_OFFSET >> 4),   // column high nibble
+                0xB0 | page as u8,        // page address
+                COL_OFFSET & 0x0F,        // column low nibble
+                0x10 | (COL_OFFSET >> 4), // column high nibble
            ])
            .await?;

@@ -90,7 +90,6 @@ impl<I: I2c> Sh1106<I> {
    pub async fn set_brightness(&mut self, value: u8) -> Result<(), I::Error> {
        self.cmd(&[0x81, value]).await
    }
-
 }

 impl<I: I2c> DrawTarget for Sh1106<I> {
@@ -6,6 +6,7 @@

 use embassy_sync::blocking_mutex::raw::NoopRawMutex;
 use esp_hal::dma::{DmaRxBuf, DmaTxBuf};
+use esp_hal::gpio::interconnect::{PeripheralInput, PeripheralOutput};
 use esp_hal::i2c::master::{Config as I2cConfig, I2c};
 use esp_hal::spi::master::{Config as SpiConfig, Spi, SpiDmaBus};
 use esp_hal::spi::Mode as SpiMode;
@@ -21,20 +22,28 @@ pub type I2cBus = I2c<'static, esp_hal::Async>;
 // ── Timer ───────────────────────────────────────────────────────────

 /// Start the ESP-RTOS scheduler and Embassy time driver.
-pub fn start_timer(timg0: esp_hal::peripherals::TIMG0<'static>) {
+pub fn start_timer(
+    timg0: esp_hal::peripherals::TIMG0<'static>,
+    sw_int: esp_hal::peripherals::SW_INTERRUPT<'static>,
+) {
    let timg0 = TimerGroup::new(timg0);
-    esp_rtos::start(timg0.timer0);
+    let sw_ints = esp_hal::interrupt::software::SoftwareInterruptControl::new(sw_int);
+    esp_rtos::start(timg0.timer0, sw_ints.software_interrupt0);
 }

 // ── SPI bus ─────────────────────────────────────────────────────────

 /// Initialize SPI2 with DMA and wrap in a shared bus (StaticCell + Mutex).
+///
+/// Generic over pin type so boards with different SPI pin assignments can
+/// share this helper. Any GPIO that implements the esp-hal interconnect
+/// traits (which is every GPIO on the ESP32-S3) can be passed directly.
 pub fn init_spi(
    spi2: esp_hal::peripherals::SPI2<'static>,
    dma_ch0: esp_hal::peripherals::DMA_CH0<'static>,
-    sck: esp_hal::peripherals::GPIO9<'static>,
-    mosi: esp_hal::peripherals::GPIO10<'static>,
-    miso: esp_hal::peripherals::GPIO11<'static>,
+    sck: impl PeripheralOutput<'static>,
+    mosi: impl PeripheralOutput<'static>,
+    miso: impl PeripheralInput<'static>,
 ) -> &'static embassy_sync::mutex::Mutex<NoopRawMutex, SpiBus> {
    let spi = Spi::new(
        spi2,
@@ -62,10 +71,13 @@ pub fn init_spi(
 // ── I2C bus ─────────────────────────────────────────────────────────

 /// Initialize I2C0 for peripherals (display, sensors, etc.).
+///
+/// Generic over pin type. I2C lines are bidirectional (open-drain), so both
+/// `PeripheralInput` and `PeripheralOutput` bounds are required.
 pub fn init_i2c(
    i2c0: esp_hal::peripherals::I2C0<'static>,
-    sda: esp_hal::peripherals::GPIO17<'static>,
-    scl: esp_hal::peripherals::GPIO18<'static>,
+    sda: impl PeripheralInput<'static> + PeripheralOutput<'static>,
+    scl: impl PeripheralInput<'static> + PeripheralOutput<'static>,
 ) -> I2cBus {
    I2c::new(i2c0, I2cConfig::default())
        .expect("I2C init")
@@ -78,5 +90,8 @@ pub fn init_i2c(

 /// Read the factory-programmed MAC address from eFuse.
 pub fn mac_address() -> [u8; 6] {
-    esp_hal::efuse::Efuse::mac_address()
+    esp_hal::efuse::base_mac_address()
+        .as_bytes()
+        .try_into()
+        .expect("MAC is 6 bytes")
 }
@@ -3,8 +3,16 @@
 //! Each submodule provides low-level bus and peripheral init for one MCU family.
 //! Board files call these with specific pins and construct higher-level drivers.

-#[cfg(any(feature = "heltec_v3", feature = "heltec_v3_uart", feature = "heltec_v4"))]
+#[cfg(any(
+    feature = "heltec_v3",
+    feature = "heltec_v3_uart",
+    feature = "heltec_v4",
+    feature = "elecrow_thinknode_m2"
+))]
 pub mod esp32s3;

 #[cfg(any(feature = "rak_wisblock_4631", feature = "wio_tracker_l1"))]
 pub mod nrf52840;
+
+#[cfg(feature = "waveshare_rp2040_lora")]
+pub mod rp2040;
@@ -25,9 +25,7 @@ pub type UsbNrfDriver =
 // ── SPI bus sharing ─────────────────────────────────────────────────

 /// Wrap an initialized SPI peripheral in a shared bus (StaticCell + Mutex).
-pub fn share_spi_bus(
-    spi: SpiBus,
-) -> &'static embassy_sync::mutex::Mutex<NoopRawMutex, SpiBus> {
+pub fn share_spi_bus(spi: SpiBus) -> &'static embassy_sync::mutex::Mutex<NoopRawMutex, SpiBus> {
    static SPI_BUS: StaticCell<embassy_sync::mutex::Mutex<NoopRawMutex, SpiBus>> =
        StaticCell::new();
    SPI_BUS.init(embassy_sync::mutex::Mutex::new(spi))
@@ -0,0 +1,80 @@
+//! RP2040 MCU initialization primitives.
+//!
+//! Provides shared boilerplate for RP2040 boards: interrupt bindings,
+//! type aliases, StaticCell bus wrapping, USB init, and MAC address reading.
+
+use embassy_rp::bind_interrupts;
+use embassy_sync::blocking_mutex::raw::NoopRawMutex;
+use static_cell::StaticCell;
+
+// ── Interrupts (shared by all RP2040 boards) ──────────────────────
+
+bind_interrupts!(pub struct Irqs {
+    USBCTRL_IRQ => embassy_rp::usb::InterruptHandler<embassy_rp::peripherals::USB>;
+    DMA_IRQ_0 => embassy_rp::dma::InterruptHandler<embassy_rp::peripherals::DMA_CH0>,
+        embassy_rp::dma::InterruptHandler<embassy_rp::peripherals::DMA_CH1>;
+});
+
+// ── MCU-level types ────────────────────────────────────────────────
+
+pub type SpiBus =
+    embassy_rp::spi::Spi<'static, embassy_rp::peripherals::SPI1, embassy_rp::spi::Async>;
+pub type UsbRpDriver = embassy_rp::usb::Driver<'static, embassy_rp::peripherals::USB>;
+
+// ── SPI bus sharing ────────────────────────────────────────────────
+
+/// Wrap an initialized SPI peripheral in a shared bus (StaticCell + Mutex).
+pub fn share_spi_bus(spi: SpiBus) -> &'static embassy_sync::mutex::Mutex<NoopRawMutex, SpiBus> {
+    static SPI_BUS: StaticCell<embassy_sync::mutex::Mutex<NoopRawMutex, SpiBus>> =
+        StaticCell::new();
+    SPI_BUS.init(embassy_sync::mutex::Mutex::new(spi))
+}
+
+// ── MAC address ────────────────────────────────────────────────────
+
+/// Store for the MAC address derived from flash unique ID.
+/// Populated once during `init_mac()`, read by `mac_address()`.
+static MAC: StaticCell<[u8; 6]> = StaticCell::new();
+static mut MAC_REF: Option<&'static [u8; 6]> = None;
+
+/// Read the flash chip's unique ID and derive a 6-byte MAC address.
+///
+/// Must be called once during board init before `mac_address()`.
+pub fn init_mac<const FLASH_SIZE: usize>(
+    flash: &mut embassy_rp::flash::Flash<
+        '_,
+        embassy_rp::peripherals::FLASH,
+        embassy_rp::flash::Blocking,
+        FLASH_SIZE,
+    >,
+) {
+    let mut uid = [0u8; 8];
+    flash.blocking_unique_id(&mut uid).expect("flash unique ID");
+
+    // XOR the first 2 bytes into bytes 2..8 to fold 8 bytes into 6,
+    // then set the locally-administered bit (byte 0, bit 1).
+    let mac = [
+        uid[2] ^ uid[0] | 0x02,
+        uid[3] ^ uid[1],
+        uid[4],
+        uid[5],
+        uid[6],
+        uid[7],
+    ];
+
+    let stored = MAC.init(mac);
+    // SAFETY: Written once during single-threaded init, before the executor
+    // starts. All subsequent reads are from &'static reference.
+    unsafe {
+        MAC_REF = Some(stored);
+    }
+}
+
+/// Return the MAC address derived from the flash unique ID.
+///
+/// Panics if `init_mac()` has not been called.
+pub fn mac_address() -> [u8; 6] {
+    // SAFETY: MAC_REF is set once during init before the executor starts,
+    // and only read (never written) after that.
+    unsafe { *MAC_REF.expect("init_mac() must be called before mac_address()") }
+}
@@ -2,87 +2,16 @@
 //!
 //! Both `usb_task` and `uart_task` use these helpers for frame
 //! accumulation, response encoding, and command routing.
+//!
+//! The actual codec lives in `donglora-protocol` so host crates can
+//! reuse it; this module re-exports the codec and owns the
+//! firmware-only [`route_command`] (which touches embassy channels).

-use defmt::warn;
+pub use donglora_protocol::framing::{cobs_encode_response, CobsDecoder, MAX_FRAME};

 use crate::channel::{CommandChannel, DisplayCommand, DisplayCommandChannel, ResponseChannel};
 use crate::protocol::{Command, ErrorCode, Response};

-/// Maximum COBS frame size (bytes).
-pub const MAX_FRAME: usize = 512;
-
-// Worst case: tag(1) + rssi(2) + snr(2) + len(2) + payload(256) = 263 bytes.
-// COBS adds ceil(263/254)+1 = 3 bytes. 266 < 512. Plenty of room.
-const _: () = assert!(
-    MAX_FRAME >= crate::protocol::MAX_PAYLOAD + 64,
-    "MAX_FRAME too small for max payload + COBS overhead"
-);
-
-/// Decodes COBS-framed commands from a byte stream.
-pub struct CobsDecoder {
-    buf: [u8; MAX_FRAME],
-    len: usize,
-}
-
-impl CobsDecoder {
-    pub const fn new() -> Self {
-        Self {
-            buf: [0u8; MAX_FRAME],
-            len: 0,
-        }
-    }
-
-    /// Reset the accumulator (discard partial frame).
-    pub fn reset(&mut self) {
-        self.len = 0;
-    }
-
-    /// Feed a chunk of bytes, calling `on_command` for each decoded command.
-    pub fn feed(&mut self, data: &[u8], mut on_command: impl FnMut(Command)) {
-        for &byte in data {
-            if byte == 0x00 {
-                // End of COBS frame — decode and dispatch
-                if self.len > 0 {
-                    let mut decode_buf = [0u8; MAX_FRAME];
-                    if let Some(decoded_len) =
-                        ucobs::decode(&self.buf[..self.len], &mut decode_buf)
-                    {
-                        if let Some(cmd) = Command::from_bytes(&decode_buf[..decoded_len]) {
-                            on_command(cmd);
-                        }
-                    }
-                }
-                self.len = 0;
-            } else if self.len < MAX_FRAME {
-                self.buf[self.len] = byte;
-                self.len += 1;
-            } else {
-                // Frame too large — discard
-                self.len = 0;
-            }
-        }
-    }
-}
-
-/// COBS-encode a response into `encode_buf` with trailing 0x00 sentinel.
-///
-/// Returns the slice to send (encoded frame + sentinel), or `None` on overflow.
-pub fn cobs_encode_response<'a>(
-    response: Response,
-    write_buf: &mut [u8; MAX_FRAME],
-    encode_buf: &'a mut [u8; MAX_FRAME],
-) -> Option<&'a [u8]> {
-    let raw_len = response.write_to(write_buf);
-    let encoded_len = ucobs::encode(&write_buf[..raw_len], encode_buf).unwrap_or(0);
-    if encoded_len < encode_buf.len() {
-        encode_buf[encoded_len] = 0x00;
-        Some(&encode_buf[..encoded_len + 1])
-    } else {
-        warn!("COBS encode buffer overflow");
-        None
-    }
-}
-
 /// Route a parsed command to the appropriate handler.
 ///
 /// Display and MAC commands are handled locally (response sent immediately).
@@ -6,7 +6,7 @@
 pub mod framing;

 cfg_if::cfg_if! {
-    if #[cfg(feature = "heltec_v3_uart")] {
+    if #[cfg(any(feature = "heltec_v3_uart", feature = "elecrow_thinknode_m2"))] {
        mod uart;
        pub use uart::host_task;
    } else {
@@ -6,8 +6,8 @@ use defmt::warn;
 use embassy_executor::task;
 use embedded_io_async::Write;

-use crate::channel::{CommandChannel, DisplayCommand, DisplayCommandChannel, ResponseChannel};
 use super::framing::{self, CobsDecoder, MAX_FRAME};
+use crate::channel::{CommandChannel, DisplayCommand, DisplayCommandChannel, ResponseChannel};

 #[task]
 pub async fn host_task(
@@ -20,9 +20,9 @@ pub async fn host_task(
 ) {
    let (mut rx, mut tx) = parts.driver.split();

-    // UART has no DTR — signal the display that a host is present at boot.
+    // UART has no DTR — assume a host is always present.
    if has_display {
-        display_commands.send(DisplayCommand::Reset).await;
+        display_commands.send(DisplayCommand::On).await;
    }

    let mut read_buf = [0u8; 64];
@@ -56,17 +56,27 @@ pub async fn host_task(
                });
                for cmd in cmds {
                    framing::route_command(
-                        cmd, commands, responses, display_commands, has_display, mac,
+                        cmd,
+                        commands,
+                        responses,
+                        display_commands,
+                        has_display,
+                        mac,
                    )
                    .await;
                }
            }
            Either::Second(response) => {
+                #[cfg(feature = "debug-checkpoint")]
+                crate::debug_blink::set(13);
                if let Some(frame) =
                    framing::cobs_encode_response(response, &mut write_buf, &mut cobs_encode_buf)
                {
                    if tx.write_all(frame).await.is_err() {
                        warn!("UART write failed, response dropped");
+                    } else {
+                        #[cfg(feature = "debug-checkpoint")]
+                        crate::debug_blink::set(14);
                    }
                }
            }
@@ -1,18 +1,112 @@
 //! USB CDC-ACM host task: COBS-framed fixed-size LE command/response protocol.
+//!
+//! ```text
+//! Host
+//! ├── Disconnected   (default)   no DTR
+//! └── Connected                  host attached
+//!     entry: wake_display
+//!     exit:  stop_radio, reset_display
+//! ```
+//!
+//! The statechart tracks exactly one thing: DTR. Entry/exit actions
+//! replace the old `was_connected` edge-detector and emit the display
+//! wake / radio-stop / display-reset side-effects that used to be open
+//! coded around the `select3` loop.
+//!
+//! The data plane (COBS decoding, command routing, response encoding)
+//! stays imperative in `protocol_loop` for the same reason the radio's
+//! `rx_once` stayed out of its chart: `read_packet` blocks and can't
+//! live inside a statechart action. Host-contract lifecycle (one
+//! outstanding command, unsolicited `RxPacket`, synchronous local
+//! responses) is deliberately *not* modeled — any finer chart here
+//! would desynchronise from the concurrent `select3` reality and lie
+//! about what the firmware is actually doing.

 use defmt::warn;
 use embassy_executor::task;
 use embassy_futures::join::join;
 use embassy_usb::class::cdc_acm::{CdcAcmClass, Receiver, Sender, State};
 use embassy_usb::Builder;
+use hsmc::{statechart, Duration};
 use static_cell::StaticCell;

+use super::framing::{self, CobsDecoder, MAX_FRAME};
 use crate::channel::{CommandChannel, DisplayCommand, DisplayCommandChannel, ResponseChannel};
 use crate::protocol::Command;
-use super::framing::{self, CobsDecoder, MAX_FRAME};

 const MAX_PACKET: usize = 64;

+/// Internal events driving `Host` state transitions.
+#[derive(Debug, Clone)]
+pub enum HostInput {
+    /// DTR rose: host opened the serial port.
+    DtrRaised,
+    /// DTR fell: host closed or disconnected.
+    DtrDropped,
+}
+
+/// Machine context — channel handles the actions need to broadcast
+/// DTR-edge side-effects. The COBS decoder, read/write scratch, and
+/// USB endpoints stay local to `protocol_loop` because their async
+/// operations can't live inside statechart actions.
+pub struct HostContext {
+    commands: &'static CommandChannel,
+    display_commands: &'static DisplayCommandChannel,
+    has_display: bool,
+}
+
+impl HostContext {
+    async fn wake_display_if_present(&self) {
+        if self.has_display {
+            self.display_commands.send(DisplayCommand::On).await;
+        }
+    }
+
+    async fn reset_display_if_present(&self) {
+        if self.has_display {
+            self.display_commands.send(DisplayCommand::Reset).await;
+        }
+    }
+
+    fn stop_radio_best_effort(&self) {
+        if self.commands.try_send(Command::StopRx).is_err() {
+            warn!("host DTR-drop: StopRx dropped (command channel full)");
+        }
+    }
+}
+
+statechart! {
+    Host {
+        context: HostContext;
+        events: HostInput;
+        default(Disconnected);
+
+        state Disconnected {
+            on(DtrRaised) => Connected;
+        }
+
+        state Connected {
+            entry: wake_display;
+            exit: stop_radio, reset_display;
+            on(DtrDropped) => Disconnected;
+        }
+    }
+}
+
+impl HostActions for HostActionContext<'_> {
+    async fn wake_display(&mut self) {
+        self.wake_display_if_present().await;
+    }
+
+    async fn stop_radio(&mut self) {
+        self.stop_radio_best_effort();
+    }
+
+    async fn reset_display(&mut self) {
+        self.reset_display_if_present().await;
+    }
+}
+
 #[task]
 pub async fn host_task(
    parts: crate::board::UsbParts,
@@ -59,7 +153,15 @@ pub async fn host_task(

    join(
        usb_dev.run(),
-        protocol_loop(sender, receiver, commands, responses, display_commands, has_display, mac),
+        protocol_loop(
+            sender,
+            receiver,
+            commands,
+            responses,
+            display_commands,
+            has_display,
+            mac,
+        ),
    )
    .await;
 }
@@ -75,11 +177,18 @@ async fn protocol_loop<'d, D: embassy_usb_driver::Driver<'d>>(
 ) {
    use embassy_futures::select::{select3, Either3};

+    let mut machine = Host::new_local(HostContext {
+        commands,
+        display_commands,
+        has_display,
+    });
+    // Enter the default: Disconnected.
+    machine.step(Duration::ZERO).await;
+
    let mut read_buf = [0u8; MAX_PACKET];
    let mut write_buf = [0u8; MAX_FRAME];
    let mut cobs_encode_buf = [0u8; MAX_FRAME];
    let mut decoder = CobsDecoder::new();
-    let mut was_connected = false;

    loop {
        match select3(
@@ -89,28 +198,32 @@ async fn protocol_loop<'d, D: embassy_usb_driver::Driver<'d>>(
        )
        .await
        {
-            Either3::First(result) => {
-                let n = match result {
-                    Ok(0) => continue,
-                    Ok(n) => n,
-                    Err(_) => {
-                        decoder.reset();
-                        embassy_time::Timer::after_millis(100).await;
-                        continue;
-                    }
-                };
-
+            Either3::First(Ok(0)) => {}
+            Either3::First(Ok(n)) => {
                let mut cmds = heapless::Vec::<_, 4>::new();
                decoder.feed(&read_buf[..n], |cmd| {
                    let _ = cmds.push(cmd);
                });
                for cmd in cmds {
                    framing::route_command(
-                        cmd, commands, responses, display_commands, has_display, mac,
+                        cmd,
+                        commands,
+                        responses,
+                        display_commands,
+                        has_display,
+                        mac,
                    )
                    .await;
                }
            }
+            Either3::First(Err(_)) => {
+                // Read errored — usually a USB disconnect. Drop decoder
+                // scratch and back off briefly so we don't spin at I/O
+                // rate. Do NOT `continue`: the DTR check below must
+                // still run so the machine's exit action fires.
+                decoder.reset();
+                embassy_time::Timer::after_millis(100).await;
+            }
            Either3::Second(response) => {
                if let Some(frame) =
                    framing::cobs_encode_response(response, &mut write_buf, &mut cobs_encode_buf)
@@ -126,16 +239,27 @@ async fn protocol_loop<'d, D: embassy_usb_driver::Driver<'d>>(
            Either3::Third(()) => {}
        }

+        // Edge-detect DTR against the machine's current state. The
+        // machine's entry/exit actions own the side-effects. dispatch()
+        // pushes the event AND drains the internal queue, so
+        // current_state() reflects the post-dispatch state before we
+        // loop back around.
        let connected = receiver.dtr();
-        if was_connected && !connected {
-            let _ = commands.try_send(Command::StopRx);
-            if has_display {
-                display_commands.send(DisplayCommand::Reset).await;
+        let was_connected = matches!(machine.current_state(), HostState::Connected);
+        match (was_connected, connected) {
+            (false, true) => {
+                let _ = machine.dispatch(HostInput::DtrRaised).await;
            }
+            (true, false) => {
+                // Belt-and-braces: reset decoder here too. The error
+                // arm above typically fires on disconnect and already
+                // resets it, but this makes intent explicit and
+                // survives embassy-usb behavior changes where a
+                // disconnect doesn't surface as a read error.
+                decoder.reset();
+                let _ = machine.dispatch(HostInput::DtrDropped).await;
+            }
+            _ => {}
        }
-        if !was_connected && connected && has_display {
-            display_commands.send(DisplayCommand::On).await;
-        }
-        was_connected = connected;
    }
 }
@@ -19,6 +19,8 @@
 mod board;
 #[cfg(not(test))]
 mod channel;
+#[cfg(all(not(test), feature = "debug-checkpoint"))]
+mod debug_blink;
 #[cfg(not(test))]
 mod display;
 #[cfg(not(test))]
@@ -37,14 +39,14 @@ use embassy_executor::Spawner;
 #[cfg(not(test))]
 use crate::board::LoRaBoard;
 #[cfg(not(test))]
-use crate::channel::{CommandChannel, DisplayCommandChannel, ResponseChannel, StatusWatch};
+use crate::channel::{CommandChannel, DisplayCommandChannel, RadioEventChannel, ResponseChannel};

 #[cfg(not(test))]
 cfg_if::cfg_if! {
-    if #[cfg(any(feature = "rak_wisblock_4631", feature = "wio_tracker_l1"))] {
+    if #[cfg(any(feature = "rak_wisblock_4631", feature = "wio_tracker_l1", feature = "waveshare_rp2040_lora"))] {
        use defmt_rtt as _;
        use panic_probe as _;
-    } else if #[cfg(any(feature = "heltec_v3", feature = "heltec_v3_uart", feature = "heltec_v4"))] {
+    } else if #[cfg(any(feature = "heltec_v3", feature = "heltec_v3_uart", feature = "heltec_v4", feature = "elecrow_thinknode_m2"))] {
        use esp_backtrace as _;
        use esp_println as _;
    }
@@ -55,18 +57,18 @@ static COMMANDS: CommandChannel = CommandChannel::new();
 #[cfg(not(test))]
 static RESPONSES: ResponseChannel = ResponseChannel::new();
 #[cfg(not(test))]
-static STATUS: StatusWatch = StatusWatch::new();
+static RADIO_EVENTS: RadioEventChannel = RadioEventChannel::new();
 #[cfg(not(test))]
 static DISPLAY_COMMANDS: DisplayCommandChannel = DisplayCommandChannel::new();

 #[cfg(not(test))]
 cfg_if::cfg_if! {
-    if #[cfg(any(feature = "rak_wisblock_4631", feature = "wio_tracker_l1"))] {
+    if #[cfg(any(feature = "rak_wisblock_4631", feature = "wio_tracker_l1", feature = "waveshare_rp2040_lora"))] {
        #[embassy_executor::main]
        async fn main(spawner: Spawner) {
            run(spawner).await;
        }
-    } else if #[cfg(any(feature = "heltec_v3", feature = "heltec_v3_uart", feature = "heltec_v4"))] {
+    } else if #[cfg(any(feature = "heltec_v3", feature = "heltec_v3_uart", feature = "heltec_v4", feature = "elecrow_thinknode_m2"))] {
        #[esp_rtos::main]
        async fn main(spawner: Spawner) {
            run(spawner).await;
@@ -79,24 +81,39 @@ async fn run(spawner: Spawner) {
    let board = <board::Board as LoRaBoard>::init();
    let parts = board.into_parts();

-    spawner
-        .spawn(radio::radio_task(parts.radio, &COMMANDS, &RESPONSES, &STATUS))
-        .expect("spawn radio_task");
+    spawner.spawn(
+        radio::radio_task(parts.radio, &COMMANDS, &RESPONSES, &RADIO_EVENTS)
+            .expect("spawn radio_task"),
+    );

-    spawner
-        .spawn(host::host_task(
+    spawner.spawn(
+        host::host_task(
            parts.host,
            &COMMANDS,
            &RESPONSES,
            &DISPLAY_COMMANDS,
            parts.display.is_some(),
            parts.mac,
-        ))
-        .expect("spawn host_task");
+        )
+        .expect("spawn host_task"),
+    );

    if let Some(dp) = parts.display {
-        spawner
-            .spawn(display::display_task(dp, parts.led, &STATUS, &DISPLAY_COMMANDS))
-            .expect("spawn display_task");
+        #[cfg(feature = "debug-checkpoint")]
+        {
+            // LED is taken over by the checkpoint blinker; the display
+            // init struct is dropped unused for this debug build.
+            let _ = dp;
+            spawner
+                .spawn(debug_blink::debug_blink_task(parts.led).expect("spawn debug_blink_task"));
+        }
+        #[cfg(not(feature = "debug-checkpoint"))]
+        {
+            #[allow(clippy::unit_arg)] // LedDriver is () for boards without LEDs
+            spawner.spawn(
+                display::display_task(dp, parts.led, &RADIO_EVENTS, &DISPLAY_COMMANDS)
+                    .expect("spawn display_task"),
+            );
+        }
    }
 }
@@ -1,707 +1,12 @@
-//! Wire protocol types and fixed-size little-endian serialization.
+//! Wire protocol types.
 //!
-//! Every integer is fixed-width LE. No varints, no zigzag.
-//! See `docs/PROTOCOL.md` for the complete specification.
-
-use heapless::Vec;
-
-/// Maximum LoRa payload size in bytes.
-pub const MAX_PAYLOAD: usize = 256;
-
-/// RadioConfig wire size (fixed).
-pub const RADIO_CONFIG_SIZE: usize = 13;
-
-/// Sentinel value for `tx_power_dbm`: use the board's maximum TX power.
-pub const TX_POWER_MAX: i8 = i8::MIN; // -128 on the wire
-
-/// Sentinel value for `preamble_len`: use the firmware default (16 symbols).
-pub const PREAMBLE_DEFAULT: u16 = 0;
-
-/// LoRa signal bandwidth.
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[cfg_attr(not(test), derive(defmt::Format))]
-#[repr(u8)]
-pub enum Bandwidth {
-    Khz7 = 0,
-    Khz10 = 1,
-    Khz15 = 2,
-    Khz20 = 3,
-    Khz31 = 4,
-    Khz41 = 5,
-    Khz62 = 6,
-    Khz125 = 7,
-    Khz250 = 8,
-    Khz500 = 9,
-}
-
-impl Bandwidth {
-    fn from_u8(v: u8) -> Option<Self> {
-        match v {
-            0 => Some(Self::Khz7),
-            1 => Some(Self::Khz10),
-            2 => Some(Self::Khz15),
-            3 => Some(Self::Khz20),
-            4 => Some(Self::Khz31),
-            5 => Some(Self::Khz41),
-            6 => Some(Self::Khz62),
-            7 => Some(Self::Khz125),
-            8 => Some(Self::Khz250),
-            9 => Some(Self::Khz500),
-            _ => None,
-        }
-    }
-}
-
-/// Complete LoRa radio configuration.
-///
-/// Wire layout (13 bytes, all little-endian):
-/// ```text
-/// [freq_hz:4] [bw:1] [sf:1] [cr:1] [sync_word:2] [tx_power_dbm:1] [preamble_len:2] [cad:1]
-/// ```
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[cfg_attr(not(test), derive(defmt::Format))]
-pub struct RadioConfig {
-    /// Frequency in Hz (150_000_000 - 960_000_000 for SX1262).
-    pub freq_hz: u32,
-    pub bw: Bandwidth,
-    /// Spreading factor (5-12).
-    pub sf: u8,
-    /// Coding rate denominator (5-8). E.g. 5 = CR 4/5, 8 = CR 4/8.
-    pub cr: u8,
-    pub sync_word: u16,
-    /// Transmit power in dBm. Set to [`TX_POWER_MAX`] (-128) for the
-    /// board's maximum.
-    pub tx_power_dbm: i8,
-    /// Preamble length in symbols. Set to [`PREAMBLE_DEFAULT`] (0) for
-    /// the firmware default (16 symbols). Valid range: 6–65535.
-    pub preamble_len: u16,
-    /// Channel Activity Detection (listen-before-talk) before TX.
-    /// 0 = disabled, non-zero = enabled. Default: 1 (enabled).
-    pub cad: u8,
-}
-
-impl RadioConfig {
-    /// Validate fields against hardware limits.
-    pub fn validate(&self, power_range: (i8, i8)) -> Result<(), &'static str> {
-        if !(150_000_000..=960_000_000).contains(&self.freq_hz) {
-            return Err("frequency out of range (150-960 MHz)");
-        }
-        if !(5..=12).contains(&self.sf) {
-            return Err("spreading factor out of range (5-12)");
-        }
-        if !(5..=8).contains(&self.cr) {
-            return Err("coding rate out of range (5-8)");
-        }
-        if self.tx_power_dbm != TX_POWER_MAX
-            && !(power_range.0..=power_range.1).contains(&self.tx_power_dbm)
-        {
-            return Err("TX power out of range for this board");
-        }
-        if self.preamble_len != PREAMBLE_DEFAULT && self.preamble_len < 6 {
-            return Err("preamble length too short (min 6)");
-        }
-        Ok(())
-    }
-
-    /// Resolve sentinel values to concrete defaults.
-    pub fn resolve(mut self, power_range: (i8, i8)) -> Self {
-        if self.tx_power_dbm == TX_POWER_MAX {
-            self.tx_power_dbm = power_range.1;
-        }
-        if self.preamble_len == PREAMBLE_DEFAULT {
-            self.preamble_len = 16;
-        }
-        self
-    }
-
-    /// Whether CAD (listen-before-talk) is enabled.
-    pub fn cad_enabled(&self) -> bool {
-        self.cad != 0
-    }
-
-    /// Serialize to fixed-size LE bytes. Returns number of bytes written (always 13).
-    pub fn write_to(self, buf: &mut [u8]) -> usize {
-        buf[0..4].copy_from_slice(&self.freq_hz.to_le_bytes());
-        buf[4] = self.bw as u8;
-        buf[5] = self.sf;
-        buf[6] = self.cr;
-        buf[7..9].copy_from_slice(&self.sync_word.to_le_bytes());
-        buf[9] = self.tx_power_dbm as u8;
-        buf[10..12].copy_from_slice(&self.preamble_len.to_le_bytes());
-        buf[12] = self.cad;
-        RADIO_CONFIG_SIZE
-    }
-
-    /// Deserialize from fixed-size LE bytes.
-    pub fn from_bytes(buf: &[u8]) -> Option<Self> {
-        if buf.len() < RADIO_CONFIG_SIZE {
-            return None;
-        }
-        Some(Self {
-            freq_hz: u32::from_le_bytes(buf[0..4].try_into().ok()?),
-            bw: Bandwidth::from_u8(buf[4])?,
-            sf: buf[5],
-            cr: buf[6],
-            sync_word: u16::from_le_bytes(buf[7..9].try_into().ok()?),
-            tx_power_dbm: buf[9] as i8,
-            preamble_len: u16::from_le_bytes(buf[10..12].try_into().ok()?),
-            cad: buf[12],
-        })
-    }
-}
-
-/// Host → firmware commands.
-#[allow(clippy::large_enum_variant)]
-#[derive(Debug, PartialEq)]
-pub enum Command {
-    Ping,
-    GetConfig,
-    SetConfig(RadioConfig),
-    StartRx,
-    StopRx,
-    Transmit {
-        config: Option<RadioConfig>,
-        payload: Vec<u8, MAX_PAYLOAD>,
-    },
-    DisplayOn,
-    DisplayOff,
-    GetMac,
-}
-
-impl Command {
-    /// Deserialize from a COBS-decoded frame.
-    pub fn from_bytes(buf: &[u8]) -> Option<Self> {
-        let tag = *buf.first()?;
-        let rest = &buf[1..];
-        match tag {
-            0 => Some(Self::Ping),
-            1 => Some(Self::GetConfig),
-            2 => Some(Self::SetConfig(RadioConfig::from_bytes(rest)?)),
-            3 => Some(Self::StartRx),
-            4 => Some(Self::StopRx),
-            5 => {
-                // Transmit: has_config:u8 + [RadioConfig if 1] + len:u16 LE + payload
-                if rest.is_empty() {
-                    return None;
-                }
-                let (config, pos) = if rest[0] == 0 {
-                    (None, 1)
-                } else if rest[0] == 1 && rest.len() > RADIO_CONFIG_SIZE {
-                    (
-                        Some(RadioConfig::from_bytes(&rest[1..])?),
-                        1 + RADIO_CONFIG_SIZE,
-                    )
-                } else {
-                    return None;
-                };
-                if rest.len() < pos + 2 {
-                    return None;
-                }
-                let len = u16::from_le_bytes(rest[pos..pos + 2].try_into().ok()?) as usize;
-                let data_start = pos + 2;
-                if rest.len() < data_start + len {
-                    return None;
-                }
-                let mut payload = Vec::new();
-                let _ = payload.extend_from_slice(&rest[data_start..data_start + len]);
-                Some(Self::Transmit { config, payload })
-            }
-            6 => Some(Self::DisplayOn),
-            7 => Some(Self::DisplayOff),
-            8 => Some(Self::GetMac),
-            _ => None,
-        }
-    }
-}
-
-/// Firmware → host responses.
-#[allow(clippy::large_enum_variant)]
-#[derive(Debug, PartialEq)]
-pub enum Response {
-    Pong,
-    Config(RadioConfig),
-    RxPacket {
-        rssi: i16,
-        snr: i16,
-        payload: Vec<u8, MAX_PAYLOAD>,
-    },
-    TxDone,
-    Ok,
-    Error(ErrorCode),
-    MacAddress([u8; 6]),
-}
-
-impl Response {
-    /// Serialize to fixed-size LE bytes. Returns number of bytes written.
-    pub fn write_to(self, buf: &mut [u8]) -> usize {
-        match self {
-            Self::Pong => {
-                buf[0] = 0;
-                1
-            }
-            Self::Config(cfg) => {
-                buf[0] = 1;
-                1 + cfg.write_to(&mut buf[1..])
-            }
-            Self::RxPacket { rssi, snr, payload } => {
-                buf[0] = 2;
-                buf[1..3].copy_from_slice(&rssi.to_le_bytes());
-                buf[3..5].copy_from_slice(&snr.to_le_bytes());
-                buf[5..7].copy_from_slice(&(payload.len() as u16).to_le_bytes());
-                buf[7..7 + payload.len()].copy_from_slice(&payload);
-                7 + payload.len()
-            }
-            Self::TxDone => {
-                buf[0] = 3;
-                1
-            }
-            Self::Ok => {
-                buf[0] = 4;
-                1
-            }
-            Self::Error(code) => {
-                buf[0] = 5;
-                buf[1] = code as u8;
-                2
-            }
-            Self::MacAddress(mac) => {
-                buf[0] = 6;
-                buf[1..7].copy_from_slice(&mac);
-                7
-            }
-        }
-    }
-}
-
-/// Error codes reported to the host.
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[cfg_attr(not(test), derive(defmt::Format))]
-#[repr(u8)]
-pub enum ErrorCode {
-    InvalidConfig = 0,
-    RadioBusy = 1,
-    TxTimeout = 2,
-    // 3 reserved (was CrcError — SX1262 silently drops bad-CRC packets)
-    NotConfigured = 4,
-    NoDisplay = 5,
-}
-
-// ── Tests ───────────────────────────────────────────────────────────
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    fn make_config() -> RadioConfig {
-        RadioConfig {
-            freq_hz: 915_000_000,
-            bw: Bandwidth::Khz125,
-            sf: 7,
-            cr: 5,
-            sync_word: 0x3444,
-            tx_power_dbm: 22,
-            preamble_len: 16,
-            cad: 1,
-        }
-    }
-
-    // ── RadioConfig roundtrip ───────────────────────────────────────
-
-    #[test]
-    fn radio_config_roundtrip() {
-        let cfg = make_config();
-        let mut buf = [0u8; RADIO_CONFIG_SIZE];
-        let n = cfg.write_to(&mut buf);
-        assert_eq!(n, RADIO_CONFIG_SIZE);
-        assert_eq!(RadioConfig::from_bytes(&buf), Some(cfg));
-    }
-
-    #[test]
-    fn radio_config_roundtrip_all_bandwidths() {
-        for bw_val in 0u8..=9 {
-            let bw = Bandwidth::from_u8(bw_val).unwrap();
-            let cfg = RadioConfig {
-                freq_hz: 433_000_000,
-                bw,
-                sf: 12,
-                cr: 8,
-                sync_word: 0x1234,
-                tx_power_dbm: -9,
-                preamble_len: 16,
-                cad: 1,
-            };
-            let mut buf = [0u8; RADIO_CONFIG_SIZE];
-            cfg.write_to(&mut buf);
-            assert_eq!(RadioConfig::from_bytes(&buf), Some(cfg));
-        }
-    }
-
-    #[test]
-    fn radio_config_roundtrip_negative_power() {
-        let cfg = RadioConfig {
-            tx_power_dbm: TX_POWER_MAX,
-            ..make_config()
-        };
-        let mut buf = [0u8; RADIO_CONFIG_SIZE];
-        cfg.write_to(&mut buf);
-        assert_eq!(RadioConfig::from_bytes(&buf), Some(cfg));
-    }
-
-    #[test]
-    fn radio_config_from_short_buffer() {
-        let buf = [0u8; RADIO_CONFIG_SIZE - 1];
-        assert!(RadioConfig::from_bytes(&buf).is_none());
-    }
-
-    #[test]
-    fn radio_config_from_empty_buffer() {
-        assert!(RadioConfig::from_bytes(&[]).is_none());
-    }
-
-    #[test]
-    fn radio_config_invalid_bandwidth() {
-        let mut buf = [0u8; RADIO_CONFIG_SIZE];
-        make_config().write_to(&mut buf);
-        buf[4] = 255; // invalid bandwidth
-        assert!(RadioConfig::from_bytes(&buf).is_none());
-    }
-
-    // ── RadioConfig::validate ───────────────────────────────────────
-
-    #[test]
-    fn validate_freq_boundaries() {
-        let power_range = (-9, 22);
-        let base = make_config();
-
-        let mut cfg = RadioConfig {
-            freq_hz: 150_000_000,
-            ..base
-        };
-        assert!(cfg.validate(power_range).is_ok());
-
-        cfg.freq_hz = 960_000_000;
-        assert!(cfg.validate(power_range).is_ok());
-
-        cfg.freq_hz = 149_999_999;
-        assert!(cfg.validate(power_range).is_err());
-
-        cfg.freq_hz = 960_000_001;
-        assert!(cfg.validate(power_range).is_err());
-    }
-
-    #[test]
-    fn validate_sf_boundaries() {
-        let power_range = (-9, 22);
-        let base = make_config();
-
-        for sf in 5..=12 {
-            assert!(RadioConfig { sf, ..base }.validate(power_range).is_ok());
-        }
-        assert!(RadioConfig { sf: 4, ..base }.validate(power_range).is_err());
-        assert!(RadioConfig { sf: 13, ..base }
-            .validate(power_range)
-            .is_err());
-    }
-
-    #[test]
-    fn validate_cr_boundaries() {
-        let power_range = (-9, 22);
-        let base = make_config();
-
-        for cr in 5..=8 {
-            assert!(RadioConfig { cr, ..base }.validate(power_range).is_ok());
-        }
-        assert!(RadioConfig { cr: 4, ..base }.validate(power_range).is_err());
-        assert!(RadioConfig { cr: 9, ..base }.validate(power_range).is_err());
-    }
-
-    #[test]
-    fn validate_tx_power_max_sentinel() {
-        let cfg = RadioConfig {
-            tx_power_dbm: TX_POWER_MAX,
-            ..make_config()
-        };
-        assert!(cfg.validate((-9, 22)).is_ok());
-    }
-
-    #[test]
-    fn validate_tx_power_out_of_range() {
-        let cfg = RadioConfig {
-            tx_power_dbm: 23,
-            ..make_config()
-        };
-        assert!(cfg.validate((-9, 22)).is_err());
-
-        let cfg = RadioConfig {
-            tx_power_dbm: -10,
-            ..make_config()
-        };
-        assert!(cfg.validate((-9, 22)).is_err());
-    }
-
-    #[test]
-    fn validate_preamble_default_sentinel() {
-        let cfg = RadioConfig {
-            preamble_len: PREAMBLE_DEFAULT,
-            ..make_config()
-        };
-        assert!(cfg.validate((-9, 22)).is_ok());
-    }
-
-    #[test]
-    fn validate_preamble_boundaries() {
-        let power_range = (-9, 22);
-        let base = make_config();
-
-        assert!(RadioConfig {
-            preamble_len: 6,
-            ..base
-        }
-        .validate(power_range)
-        .is_ok());
-        assert!(RadioConfig {
-            preamble_len: 5,
-            ..base
-        }
-        .validate(power_range)
-        .is_err());
-    }
-
-    // ── RadioConfig::resolve ──────────────────────────────────────
-
-    #[test]
-    fn resolve_power_max_sentinel() {
-        let cfg = RadioConfig {
-            tx_power_dbm: TX_POWER_MAX,
-            ..make_config()
-        };
-        assert_eq!(cfg.resolve((-9, 22)).tx_power_dbm, 22);
-    }
-
-    #[test]
-    fn resolve_power_explicit_unchanged() {
-        let cfg = RadioConfig {
-            tx_power_dbm: 10,
-            ..make_config()
-        };
-        assert_eq!(cfg.resolve((-9, 22)).tx_power_dbm, 10);
-    }
-
-    #[test]
-    fn resolve_preamble_default() {
-        let cfg = RadioConfig {
-            preamble_len: PREAMBLE_DEFAULT,
-            ..make_config()
-        };
-        assert_eq!(cfg.resolve((-9, 22)).preamble_len, 16);
-    }
-
-    #[test]
-    fn resolve_preamble_explicit_unchanged() {
-        let cfg = RadioConfig {
-            preamble_len: 32,
-            ..make_config()
-        };
-        assert_eq!(cfg.resolve((-9, 22)).preamble_len, 32);
-    }
-
-    // ── Command::from_bytes ─────────────────────────────────────────
-
-    #[test]
-    fn command_ping() {
-        assert_eq!(Command::from_bytes(&[0]), Some(Command::Ping));
-    }
-
-    #[test]
-    fn command_get_config() {
-        assert_eq!(Command::from_bytes(&[1]), Some(Command::GetConfig));
-    }
-
-    #[test]
-    fn command_set_config() {
-        let cfg = make_config();
-        let mut buf = [0u8; 1 + RADIO_CONFIG_SIZE];
-        buf[0] = 2;
-        cfg.write_to(&mut buf[1..]);
-        assert_eq!(Command::from_bytes(&buf), Some(Command::SetConfig(cfg)));
-    }
-
-    #[test]
-    fn command_start_stop_rx() {
-        assert_eq!(Command::from_bytes(&[3]), Some(Command::StartRx));
-        assert_eq!(Command::from_bytes(&[4]), Some(Command::StopRx));
-    }
-
-    #[test]
-    fn command_transmit_no_config() {
-        let payload = b"hello";
-        let mut buf = [0u8; 64];
-        buf[0] = 5; // tag
-        buf[1] = 0; // has_config = false
-        buf[2..4].copy_from_slice(&(payload.len() as u16).to_le_bytes());
-        buf[4..9].copy_from_slice(payload);
-
-        match Command::from_bytes(&buf[..9]).unwrap() {
-            Command::Transmit { config, payload: p } => {
-                assert!(config.is_none());
-                assert_eq!(p.as_slice(), b"hello");
-            }
-            _ => panic!("expected Transmit"),
-        }
-    }
-
-    #[test]
-    fn command_transmit_with_config() {
-        let cfg = make_config();
-        let mut buf = [0u8; 64];
-        buf[0] = 5; // tag
-        buf[1] = 1; // has_config = true
-        cfg.write_to(&mut buf[2..]);
-        let payload = b"test";
-        let pos = 2 + RADIO_CONFIG_SIZE;
-        buf[pos..pos + 2].copy_from_slice(&(payload.len() as u16).to_le_bytes());
-        buf[pos + 2..pos + 6].copy_from_slice(payload);
-
-        match Command::from_bytes(&buf[..pos + 6]).unwrap() {
-            Command::Transmit { config, payload: p } => {
-                assert_eq!(config, Some(cfg));
-                assert_eq!(p.as_slice(), b"test");
-            }
-            _ => panic!("expected Transmit"),
-        }
-    }
-
-    #[test]
-    fn command_transmit_empty_payload() {
-        let mut buf = [0u8; 4];
-        buf[0] = 5; // tag
-        buf[1] = 0; // has_config = false
-        buf[2..4].copy_from_slice(&0u16.to_le_bytes());
-
-        match Command::from_bytes(&buf).unwrap() {
-            Command::Transmit { config, payload } => {
-                assert!(config.is_none());
-                assert!(payload.is_empty());
-            }
-            _ => panic!("expected Transmit"),
-        }
-    }
-
-    #[test]
-    fn command_transmit_truncated() {
-        // Tag only — missing has_config byte
-        assert!(Command::from_bytes(&[5]).is_none());
-
-        // has_config=1 but no config bytes
-        assert!(Command::from_bytes(&[5, 1]).is_none());
-
-        // has_config=0 but no length bytes
-        assert!(Command::from_bytes(&[5, 0]).is_none());
-
-        // has_config=0, length says 5 but only 2 bytes of payload
-        let mut buf = [0u8; 6];
-        buf[0] = 5;
-        buf[1] = 0;
-        buf[2..4].copy_from_slice(&5u16.to_le_bytes());
-        buf[4] = 0xAA;
-        buf[5] = 0xBB;
-        assert!(Command::from_bytes(&buf).is_none());
-    }
-
-    #[test]
-    fn command_display_and_mac() {
-        assert_eq!(Command::from_bytes(&[6]), Some(Command::DisplayOn));
-        assert_eq!(Command::from_bytes(&[7]), Some(Command::DisplayOff));
-        assert_eq!(Command::from_bytes(&[8]), Some(Command::GetMac));
-    }
-
-    #[test]
-    fn command_invalid_tag() {
-        assert!(Command::from_bytes(&[9]).is_none());
-        assert!(Command::from_bytes(&[255]).is_none());
-    }
-
-    #[test]
-    fn command_empty_buffer() {
-        assert!(Command::from_bytes(&[]).is_none());
-    }
-
-    // ── Response::write_to ──────────────────────────────────────────
-
-    #[test]
-    fn response_pong() {
-        let mut buf = [0u8; 1];
-        assert_eq!(Response::Pong.write_to(&mut buf), 1);
-        assert_eq!(buf[0], 0);
-    }
-
-    #[test]
-    fn response_config() {
-        let cfg = make_config();
-        let mut buf = [0u8; 1 + RADIO_CONFIG_SIZE];
-        let n = Response::Config(cfg).write_to(&mut buf);
-        assert_eq!(n, 1 + RADIO_CONFIG_SIZE);
-        assert_eq!(buf[0], 1);
-        assert_eq!(RadioConfig::from_bytes(&buf[1..]), Some(cfg));
-    }
-
-    #[test]
-    fn response_rx_packet() {
-        let mut payload = Vec::new();
-        let _ = payload.extend_from_slice(b"data");
-        let mut buf = [0u8; 64];
-        let n = Response::RxPacket {
-            rssi: -80,
-            snr: 10,
-            payload,
-        }
-        .write_to(&mut buf);
-        assert_eq!(n, 7 + 4); // tag(1) + rssi(2) + snr(2) + len(2) + "data"(4)
-        assert_eq!(buf[0], 2);
-        assert_eq!(i16::from_le_bytes([buf[1], buf[2]]), -80);
-        assert_eq!(i16::from_le_bytes([buf[3], buf[4]]), 10);
-        assert_eq!(u16::from_le_bytes([buf[5], buf[6]]), 4);
-        assert_eq!(&buf[7..11], b"data");
-    }
-
-    #[test]
-    fn response_tx_done() {
-        let mut buf = [0u8; 1];
-        assert_eq!(Response::TxDone.write_to(&mut buf), 1);
-        assert_eq!(buf[0], 3);
-    }
-
-    #[test]
-    fn response_ok() {
-        let mut buf = [0u8; 1];
-        assert_eq!(Response::Ok.write_to(&mut buf), 1);
-        assert_eq!(buf[0], 4);
-    }
-
-    #[test]
-    fn response_error_codes() {
-        let mut buf = [0u8; 2];
-        for (code, val) in [
-            (ErrorCode::InvalidConfig, 0),
-            (ErrorCode::RadioBusy, 1),
-            (ErrorCode::TxTimeout, 2),
-            (ErrorCode::NotConfigured, 4),
-            (ErrorCode::NoDisplay, 5),
-        ] {
-            let n = Response::Error(code).write_to(&mut buf);
-            assert_eq!(n, 2);
-            assert_eq!(buf[0], 5);
-            assert_eq!(buf[1], val);
-        }
-    }
-
-    #[test]
-    fn response_mac_address() {
-        let mac = [0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF];
-        let mut buf = [0u8; 7];
-        let n = Response::MacAddress(mac).write_to(&mut buf);
-        assert_eq!(n, 7);
-        assert_eq!(buf[0], 6);
-        assert_eq!(&buf[1..7], &mac);
-    }
-}
+//! The definitions live in the `donglora-protocol` crate so host-side
+//! Rust projects (client-rs, mux-rs, bridge) can share them with the
+//! firmware without duplicating wire layouts. This module re-exports
+//! them unchanged for existing `crate::protocol::*` call sites.
+
+#[allow(unused_imports)]
+pub use donglora_protocol::{
+    Bandwidth, Command, ErrorCode, RadioConfig, Response, MAX_PAYLOAD, PREAMBLE_DEFAULT,
+    RADIO_CONFIG_SIZE, TX_POWER_MAX,
+};
@@ -1,272 +1,593 @@
-//! LoRa radio task: SX1262 state machine driven by host commands.
-//!
-//! Owns the radio peripheral exclusively. Receives [`Command`]s from the USB
-//! task, drives the SX1262 via [`lora_phy`], and sends [`Response`]s back.
-//! Publishes [`RadioStatus`] to the display task via a watch channel.
-//!
-//! # State machine
+//! LoRa radio task: SX1262 statechart driven by host commands.
 //!
 //! ```text
-//! Idle ──StartRx──► Receiving ──StopRx──► Idle
-//!   │                    │
-//!   └──Transmit──► Transmitting ──TxDone──► (previous state)
+//! Radio
+//! ├── Unconfigured   (default)   no config cached → no RF ops possible
+//! └── Configured
+//!     ├── Idle          (default)  ready, waiting
+//!     ├── StartingRx               brief: HW init in response to host
+//!     │                            CmdStartRx; sends Ok/Error then →
+//!     │                            Receiving (Ok) or Idle (Err)
+//!     ├── Receiving                continuous RX
+//!     ├── ResumingRx               brief: post-TX HW re-arm; silently
+//!     │                            → Receiving (Ok) or Idle (Err)
+//!     └── Transmitting
+//!         ├── FromIdle  (default)  TxDone/TxFailed → Idle
+//!         └── FromRx                TxDone → ResumingRx, TxFailed → Idle
 //! ```
 //!
-//! # Invariants
+//! The task body is a single `machine.run().await`. All I/O lives inside
+//! state-scoped `during:` activities:
 //!
-//! - This task never panics. All errors are reported to the host or logged.
-//! - Config is validated before use (see [`RadioConfig::validate`]).
+//! * Root-level `during: next_command(commands)` continuously reads the
+//!   host CommandChannel and converts each command into a `RadioInput`
+//!   event.
+//! * `Receiving.during: next_packet(lora, rx_buf)` runs the SX1262 RX
+//!   and yields `PacketReceived` events.
+//! * `TransmittingFromIdle/FromRx.during: perform_tx(lora, pending_tx)`
+//!   drives `do_tx` and yields `TransmitDone`/`TransmitFailed`.

 use defmt::{error, info, warn};
 use embassy_executor::task;
-use embassy_futures::select::{select, Either};
+use embassy_sync::blocking_mutex::raw::CriticalSectionRawMutex;
+use embassy_sync::channel::Channel;
 use embassy_time::Delay;
+use hsmc::statechart;
 use lora_phy::mod_params::RadioError;
 use lora_phy::{LoRa, RxMode};

 use crate::board::{Board, LoRaBoard, RadioDriver, RadioParts};
-use crate::channel::{CommandChannel, RadioState, RadioStatus, ResponseChannel, StatusWatch};
+use crate::channel::{CommandChannel, RadioEvent, RadioEventChannel, ResponseChannel};
 use crate::protocol::{self, Command, ErrorCode, RadioConfig, Response};

 const MAX_PAYLOAD: usize = protocol::MAX_PAYLOAD;
-// TX power range comes from the board trait: Board::TX_POWER_RANGE

-type Radio = LoRa<RadioDriver, Delay>;
+type LoRaDriver = LoRa<RadioDriver, Delay>;

 // ── Fixed LoRa radio parameters ─────────────────────────────────────
-//
-// These are intentionally not host-configurable. They are sensible
-// defaults for a general-purpose LoRa pipe. Making them configurable
-// would add protocol complexity for marginal benefit.
-
-/// Explicit header mode (variable-length packets).
 const IMPLICIT_HEADER: bool = false;
-
-/// Enable CRC on received/transmitted packets.
 const CRC_ON: bool = true;
-
-/// Standard IQ polarity (not inverted).
 const IQ_INVERTED: bool = false;

-// ── Task entry point ────────────────────────────────────────────────
+/// A pending TX request staged by an incoming `Transmit` command, consumed
+/// by the `perform_tx` during activity when the machine enters a
+/// `Transmitting.*` state. `config` is `None` when the command asked to
+/// reuse the cached config; the `stage_tx` handler resolves the effective
+/// config.
+#[derive(Debug, Clone)]
+pub struct PendingTx {
+    pub config: Option<RadioConfig>,
+    pub payload: heapless::Vec<u8, MAX_PAYLOAD>,
+}
+
+/// Events driving the radio statechart. Host commands arrive as `Cmd*`
+/// variants via the `next_command` during; low-level I/O results arrive
+/// as internal variants via the `next_packet` / `perform_tx` durings.
+#[derive(Debug, Clone)]
+pub enum RadioInput {
+    // Commands flowing in from the host via CommandChannel:
+    CmdPing,
+    CmdGetConfig,
+    CmdSetConfig(RadioConfig),
+    CmdStartRx,
+    CmdStopRx,
+    CmdTransmit(PendingTx),
+
+    // Internal events from the RX during activity:
+    PacketReceived {
+        rssi: i16,
+        snr: i16,
+        len: u8,
+        data: heapless::Vec<u8, MAX_PAYLOAD>,
+    },
+    RxFailed(&'static str),
+
+    // Internal events from `try_start_rx_hw` (the entry action of
+    // StartingRx and ResumingRx). Two distinct states consume these,
+    // and their differing transitions are how the chart encodes whether
+    // the original trigger was a host CmdStartRx (must respond) or a
+    // post-TX RX re-arm (must NOT respond).
+    StartRxOk,
+    StartRxFailed(&'static str),
+
+    // Internal events from the TX during activity:
+    TransmitDone,
+    TransmitFailed(&'static str),
+}
+
+/// Root context. Owns the LoRa driver, the RX scratch buffer, the cached
+/// configuration, the outbound event + response channels, and a staging
+/// slot for pending TX requests.
+pub struct RadioContext {
+    pub commands: &'static CommandChannel,
+    pub responses: &'static ResponseChannel,
+    pub events: &'static RadioEventChannel,
+    pub lora: LoRaDriver,
+    pub rx_buf: [u8; MAX_PAYLOAD],
+    pub config: Option<RadioConfig>,
+    pub pending_tx: Option<PendingTx>,
+}
+
+impl RadioContext {
+    fn announce(&self, ev: RadioEvent) {
+        if self.events.try_send(ev).is_err() {
+            warn!("radio event dropped: downstream queue full");
+        }
+    }
+}
+
+statechart! {
+    Radio {
+        context: RadioContext;
+        events: RadioInput;
+        default(Unconfigured);
+
+        // Commands handled the same way in every state. The actual command
+        // read — `during: next_command(commands)` — is placed only on states
+        // where commands are safe to interleave (NOT on Transmitting.*:
+        // canceling perform_tx mid-flight would abort a LoRa TX).
+        on(CmdPing) => respond_pong;
+        on(CmdGetConfig) => respond_get_config;
+
+        state Unconfigured {
+            during: next_command(commands);
+            on(CmdSetConfig(cfg: RadioConfig)) => cache_config;
+            on(CmdSetConfig) => Configured;
+            // Pre-configuration, only Ping/GetConfig make sense.
+            on(CmdStartRx) => respond_not_configured;
+            on(CmdStopRx) => respond_not_configured;
+            on(CmdTransmit) => respond_not_configured;
+        }
+
+        state Configured {
+            on(CmdSetConfig(cfg: RadioConfig)) => cache_config;
+            default(Idle);
+
+            state Idle {
+                entry: announce_idle;
+                during: next_command(commands);
+                on(CmdStartRx) => StartingRx;
+                on(CmdTransmit(p: PendingTx)) => stage_tx;
+                on(CmdTransmit) => TransmittingFromIdle;
+                on(CmdStopRx) => respond_ok;
+            }
+
+            // Brief intermediate state: a host `StartRx` is in flight,
+            // hardware is being configured. `try_start_rx_hw` (entry)
+            // emits `StartRxOk` or `StartRxFailed`; the transitions from
+            // here are what tell the host whether RX actually started.
+            // No `during: next_command` — this state is self-driven and
+            // we don't want to interleave other commands with the ack.
+            state StartingRx {
+                entry: try_start_rx_hw;
+                on(StartRxOk) => respond_ok, Receiving;
+                on(StartRxFailed(err: &'static str)) => respond_start_rx_error;
+                on(StartRxFailed) => Idle;
+            }
+
+            state Receiving {
+                entry: announce_entered_rx;
+                during: next_command(commands);
+                during: next_packet(lora, rx_buf, config);
+                // Idempotent ack: a redundant StartRx (same client re-issuing,
+                // or another client's request that mux still chose to forward)
+                // gets `Ok` without re-touching hardware.
+                on(CmdStartRx) => respond_ok;
+                on(PacketReceived {
+                    rssi: i16,
+                    snr: i16,
+                    len: u8,
+                    data: heapless::Vec<u8, MAX_PAYLOAD>,
+                }) => record_packet;
+                on(RxFailed(err: &'static str)) => announce_rx_failed;
+                on(RxFailed) => Idle;
+                on(CmdStopRx) => stop_rx_hw, respond_ok;
+                on(CmdStopRx) => Idle;
+                on(CmdTransmit(p: PendingTx)) => stage_tx;
+                on(CmdTransmit) => TransmittingFromRx;
+            }
+
+            // Brief intermediate state: a TX from `Receiving` just
+            // finished and the radio needs to be put back into RX mode.
+            // Same `try_start_rx_hw` entry as `StartingRx`, but the
+            // transitions DO NOT send a response — `respond_tx_done` was
+            // already sent by the TransmittingFromRx → here transition.
+            state ResumingRx {
+                entry: try_start_rx_hw;
+                on(StartRxOk) => Receiving;
+                on(StartRxFailed) => Idle;
+            }
+
+            // Transmitting.* deliberately has no `next_command` during: the
+            // TX operation inside `perform_tx` cannot be safely cancelled
+            // by an incoming host command. Commands arriving during TX
+            // queue on the CommandChannel and are processed by the next
+            // state that reads them (Idle or Receiving).
+            state Transmitting {
+                entry: announce_entered_tx;
+                exit: announce_packet_tx;
+                default(TransmittingFromIdle);
+
+                state TransmittingFromIdle {
+                    during: perform_tx(lora, pending_tx);
+                    on(TransmitDone) => respond_tx_done;
+                    on(TransmitDone) => Idle;
+                    on(TransmitFailed(err: &'static str)) => respond_tx_failed;
+                    on(TransmitFailed) => Idle;
+                }
+
+                state TransmittingFromRx {
+                    during: perform_tx(lora, pending_tx);
+                    on(TransmitDone) => respond_tx_done;
+                    on(TransmitDone) => ResumingRx;
+                    on(TransmitFailed(err: &'static str)) => respond_tx_failed;
+                    on(TransmitFailed) => Idle;
+                }
+            }
+        }
+    }
+}
+
+// ── during: activities ──────────────────────────────────────────────
+
+/// Bridges the host's `CommandChannel` (typed `Command`) into the
+/// machine's event stream. Each awaited command becomes one `RadioInput`.
+async fn next_command(commands: &mut &'static CommandChannel) -> RadioInput {
+    let cmd = commands.receive().await;
+    match cmd {
+        Command::Ping => RadioInput::CmdPing,
+        Command::GetConfig => RadioInput::CmdGetConfig,
+        Command::SetConfig(cfg) => RadioInput::CmdSetConfig(cfg),
+        Command::StartRx => RadioInput::CmdStartRx,
+        Command::StopRx => RadioInput::CmdStopRx,
+        Command::Transmit { config, payload } => {
+            // Mark the moment we learned about the Transmit command.
+            // This runs before the latch engages, so it's visible as a
+            // distinct LED value (18) when the firmware is sitting in
+            // Receiving (5) waiting for something to process — if LED
+            // stays on 5, the command never arrived at the firmware
+            // (mux / UART delay); if LED flashes through 18 then deeper,
+            // the command arrived normally.
+            #[cfg(feature = "debug-checkpoint")]
+            crate::debug_blink::set(18);
+            // The `stage_tx` handler resolves the effective config from
+            // either the inline `config` or the cached one.
+            RadioInput::CmdTransmit(PendingTx { config, payload })
+        }
+        Command::DisplayOn | Command::DisplayOff | Command::GetMac => {
+            // These are dispatched elsewhere in the host; if they land
+            // here it's a routing bug. Map to Ping → Pong for minimum
+            // harm (better: surface an error; there's no "unknown
+            // command" variant today).
+            RadioInput::CmdPing
+        }
+    }
+}
+
+/// Runs one iteration of continuous RX. Produces a `PacketReceived` event
+/// on success or `RxFailed` on error. The radio was configured for
+/// continuous RX by `try_start_rx_hw` (entry action of `StartingRx` /
+/// `ResumingRx`) before the chart entered `Receiving`; each iteration
+/// of this during awaits the next packet.
+async fn next_packet(
+    lora: &mut LoRaDriver,
+    rx_buf: &mut [u8; MAX_PAYLOAD],
+    config: &mut Option<RadioConfig>,
+) -> RadioInput {
+    let Some(cfg) = config.as_ref() else {
+        return RadioInput::RxFailed("no cached config");
+    };
+    let mdltn = match modulation_params(lora, cfg) {
+        Ok(m) => m,
+        Err(_) => return RadioInput::RxFailed("mdltn"),
+    };
+    let pkt = match lora.create_rx_packet_params(
+        cfg.preamble_len,
+        IMPLICIT_HEADER,
+        MAX_PAYLOAD as u8,
+        CRC_ON,
+        IQ_INVERTED,
+        &mdltn,
+    ) {
+        Ok(p) => p,
+        Err(_) => return RadioInput::RxFailed("pkt_params"),
+    };
+    match lora.rx(&pkt, rx_buf).await {
+        Ok((len, status)) => {
+            let copy_len = (len as usize).min(MAX_PAYLOAD);
+            let mut data: heapless::Vec<u8, MAX_PAYLOAD> = heapless::Vec::new();
+            let _ = data.extend_from_slice(&rx_buf[..copy_len]);
+            RadioInput::PacketReceived {
+                rssi: status.rssi,
+                snr: status.snr,
+                len,
+                data,
+            }
+        }
+        Err(_e) => RadioInput::RxFailed("rx"),
+    }
+}
+
+/// Drives one TX operation using a staged `PendingTx`. Produces
+/// `TransmitDone` on success or `TransmitFailed` on error.
+async fn perform_tx(lora: &mut LoRaDriver, pending: &mut Option<PendingTx>) -> RadioInput {
+    #[cfg(feature = "debug-checkpoint")]
+    crate::debug_blink::set(6);
+    let Some(tx) = pending.take() else {
+        #[cfg(feature = "debug-checkpoint")]
+        crate::debug_blink::set(15);
+        return RadioInput::TransmitFailed("no pending tx");
+    };
+    let Some(cfg) = tx.config.as_ref() else {
+        #[cfg(feature = "debug-checkpoint")]
+        crate::debug_blink::set(15);
+        return RadioInput::TransmitFailed("no effective config");
+    };
+    match do_tx(lora, cfg, &tx.payload).await {
+        Ok(()) => {
+            #[cfg(feature = "debug-checkpoint")]
+            crate::debug_blink::set(10);
+            RadioInput::TransmitDone
+        }
+        Err(_) => {
+            #[cfg(feature = "debug-checkpoint")]
+            crate::debug_blink::set(15);
+            RadioInput::TransmitFailed("tx")
+        }
+    }
+}
+
+// ── Actions ─────────────────────────────────────────────────────────
+
+impl RadioActions for RadioActionContext<'_> {
+    // ── responses ────────────────────────────────────────────────────
+    async fn respond_pong(&mut self) {
+        self.responses.send(Response::Pong).await;
+    }
+
+    async fn respond_get_config(&mut self) {
+        match self.config {
+            Some(cfg) => self.responses.send(Response::Config(cfg)).await,
+            None => {
+                self.responses
+                    .send(Response::Error(ErrorCode::NotConfigured))
+                    .await;
+            }
+        }
+    }
+
+    async fn respond_ok(&mut self) {
+        // try_send: StopRx after RX with full response channel is
+        // tolerable — host is disconnected.
+        let _ = self.responses.try_send(Response::Ok);
+    }
+
+    async fn respond_not_configured(&mut self) {
+        self.responses
+            .send(Response::Error(ErrorCode::NotConfigured))
+            .await;
+    }
+
+    async fn respond_tx_done(&mut self) {
+        #[cfg(feature = "debug-checkpoint")]
+        crate::debug_blink::set(11);
+        self.responses.send(Response::TxDone).await;
+        #[cfg(feature = "debug-checkpoint")]
+        crate::debug_blink::set(12);
+    }
+
+    async fn respond_tx_failed(&mut self, _err: &'static str) {
+        self.responses
+            .send(Response::Error(ErrorCode::TxTimeout))
+            .await;
+    }
+
+    // ── state bookkeeping ─────────────────────────────────────────────
+    async fn cache_config(&mut self, cfg: RadioConfig) {
+        if let Err(reason) = cfg.validate(Board::TX_POWER_RANGE) {
+            warn!("SetConfig rejected: {}", reason);
+            self.responses
+                .send(Response::Error(ErrorCode::InvalidConfig))
+                .await;
+            return;
+        }
+        let resolved = cfg.resolve(Board::TX_POWER_RANGE);
+        self.config = Some(resolved);
+        self.announce(RadioEvent::ConfigChanged(resolved));
+        self.responses.send(Response::Ok).await;
+    }
+
+    async fn stage_tx(&mut self, p: PendingTx) {
+        let effective = p.config.or(self.config);
+        let Some(cfg) = effective else {
+            self.responses
+                .send(Response::Error(ErrorCode::NotConfigured))
+                .await;
+            return;
+        };
+        if let Err(reason) = cfg.validate(Board::TX_POWER_RANGE) {
+            warn!("TX config rejected: {}", reason);
+            self.responses
+                .send(Response::Error(ErrorCode::InvalidConfig))
+                .await;
+            return;
+        }
+        let resolved = cfg.resolve(Board::TX_POWER_RANGE);
+        self.pending_tx = Some(PendingTx {
+            config: Some(resolved),
+            payload: p.payload,
+        });
+    }
+
+    // ── RX hardware ──────────────────────────────────────────────────
+
+    /// Entry action for `StartingRx` and `ResumingRx`. Performs HW init
+    /// and emits `StartRxOk` on success or `StartRxFailed` on failure.
+    /// Whether the host receives a Response::Ok / Response::Error is
+    /// decided by the parent state (StartingRx responds; ResumingRx is
+    /// silent — `respond_tx_done` already went out).
+    async fn try_start_rx_hw(&mut self) {
+        let Some(cfg) = self.config else {
+            error!("try_start_rx_hw: no config cached — state invariant broken");
+            let _ = self.emit(RadioInput::StartRxFailed("no config"));
+            return;
+        };
+        match start_rx(&mut self.lora, &cfg).await {
+            Ok(()) => {
+                let _ = self.emit(RadioInput::StartRxOk);
+            }
+            Err(e) => {
+                warn!("start_rx failed: {}", e);
+                #[cfg(feature = "debug-checkpoint")]
+                crate::debug_blink::set(17);
+                let _ = self.emit(RadioInput::StartRxFailed("start_rx"));
+            }
+        }
+    }
+
+    async fn respond_start_rx_error(&mut self, _err: &'static str) {
+        self.responses
+            .send(Response::Error(ErrorCode::InvalidConfig))
+            .await;
+    }
+
+    async fn stop_rx_hw(&mut self) {
+        let _ = self.lora.enter_standby().await;
+    }
+
+    // ── announcements ────────────────────────────────────────────────
+    async fn announce_idle(&mut self) {
+        #[cfg(feature = "debug-checkpoint")]
+        crate::debug_blink::set(4);
+        self.announce(RadioEvent::Idle);
+    }
+    async fn announce_entered_rx(&mut self) {
+        #[cfg(feature = "debug-checkpoint")]
+        crate::debug_blink::set(5);
+        self.announce(RadioEvent::EnteredRx);
+    }
+    async fn announce_entered_tx(&mut self) {
+        self.announce(RadioEvent::EnteredTx);
+    }
+    async fn announce_packet_tx(&mut self) {
+        self.announce(RadioEvent::PacketTx);
+    }
+    async fn announce_rx_failed(&mut self, _err: &'static str) {
+        self.announce(RadioEvent::Idle);
+    }
+
+    // ── packet bookkeeping ────────────────────────────────────────────
+    async fn record_packet(
+        &mut self,
+        rssi: i16,
+        snr: i16,
+        _len: u8,
+        data: heapless::Vec<u8, MAX_PAYLOAD>,
+    ) {
+        self.announce(RadioEvent::PacketRx {
+            rssi,
+            snr: Some(snr),
+        });
+        let response = Response::RxPacket {
+            rssi,
+            snr,
+            payload: data,
+        };
+        if self.responses.try_send(response).is_err() {
+            warn!("RX packet dropped: response channel full");
+        }
+    }
+}
+
+// ── Debug-checkpoint mapping (see `crate::debug_blink`) ─────────────
+//
+// Boot / steady states (latch is INACTIVE — values overwrite normally):
+//   1  boot: radio_task entered
+//   2  boot: LoRa::new ok (driver is live)
+//   3  boot: machine constructed, about to enter run()
+//   4  in Idle state (announce_idle ran)
+//   5  in Receiving state (announce_entered_rx ran — HW is in RX)
+//
+// TX phases 6–15 (linear; latch ENGAGES only on `set(6)`; only deeper
+// TX-phase writes can update; 14/15 are terminal and freeze the latch):
+//   6  TX phase 1: entered perform_tx
+//   7  TX phase 2: in CAD (prepare_for_cad / cad loop)
+//   8  TX phase 3: in prepare_for_tx (SPI config write)
+//   9  TX phase 4: awaiting tx() completion (on-air transmit)
+//  10  TX phase 5: do_tx returned Ok (back in perform_tx)
+//  11  TX phase 6: respond_tx_done handler entered
+//  12  TX phase 7: responses.send(TxDone) completed (radio side done)
+//  13  TX phase 8: host_task received the response from channel (set in host/uart.rs)
+//  14  TX phase 9: host_task wrote response to UART — TERMINAL success
+//  15  TX errored somewhere — TERMINAL error
+//
+// Boot-time errors (can only be seen before any TX engages the latch):
+//  16  LoRa::new failed at boot (degraded_loop branch)
+//  17  try_start_rx_hw failed (radio HW init returned Err)

 #[task]
 pub async fn radio_task(
    parts: RadioParts,
    commands: &'static CommandChannel,
    responses: &'static ResponseChannel,
-    status: &'static StatusWatch,
+    events: &'static RadioEventChannel,
 ) {
-    let mut state = RadioStatus::default();
-    status.sender().send(state.clone());
+    #[cfg(feature = "debug-checkpoint")]
+    crate::debug_blink::set(1);

-    let mut lora = match LoRa::new(parts.driver, false, parts.delay).await {
-        Ok(l) => l,
+    // Init the radio BEFORE the machine exists in any meaningful way —
+    // a failure here never touches the statechart; we just run a
+    // Ping-only loop forever.
+    let lora = match LoRa::new(parts.driver, false, parts.delay).await {
+        Ok(l) => {
+            info!("radio initialized");
+            #[cfg(feature = "debug-checkpoint")]
+            crate::debug_blink::set(2);
+            l
+        }
        Err(e) => {
            error!("radio init failed: {}", e);
+            #[cfg(feature = "debug-checkpoint")]
+            crate::debug_blink::set(16);
            responses
                .send(Response::Error(ErrorCode::InvalidConfig))
                .await;
-            // Radio is non-functional — respond to commands but can't do RF.
-            loop {
-                let cmd = commands.receive().await;
-                if let Command::Ping = cmd {
-                    responses.send(Response::Pong).await;
-                } else {
-                    responses
-                        .send(Response::Error(ErrorCode::InvalidConfig))
-                        .await;
-                }
-            }
+            degraded_loop(commands, responses).await;
+            return;
        }
    };

-    info!("radio initialized");
-    let mut rx_buf = [0u8; MAX_PAYLOAD];
+    let ctx = RadioContext {
+        commands,
+        responses,
+        events,
+        lora,
+        rx_buf: [0u8; MAX_PAYLOAD],
+        config: None,
+        pending_tx: None,
+    };

-    loop {
-        if state.state == RadioState::Receiving {
-            // Defensive: config must be Some when Receiving. If not, recover.
-            let cfg = match state.config {
-                Some(c) => c,
-                None => {
-                    warn!("BUG: receiving without config, returning to idle");
-                    state.state = RadioState::Idle;
-                    status.sender().send(state.clone());
-                    continue;
-                }
-            };
-
-            match select(rx_once(&mut lora, &cfg, &mut rx_buf), commands.receive()).await {
-                Either::First(rx_result) => match rx_result {
-                    Ok((len, pkt_status)) => {
-                        state.rx_count = state.rx_count.wrapping_add(1);
-                        state.last_rssi = Some(pkt_status.rssi);
-                        state.last_snr = Some(pkt_status.snr);
-                        status.sender().send(state.clone());
-
-                        let copy_len = (len as usize).min(MAX_PAYLOAD);
-                        if (len as usize) > copy_len {
-                            warn!("RX payload truncated: {} > {}", len, MAX_PAYLOAD);
-                        }
-                        let mut payload = heapless::Vec::new();
-                        // copy_len <= MAX_PAYLOAD == Vec capacity, so this cannot fail.
-                        let _ = payload.extend_from_slice(&rx_buf[..copy_len]);
-
-                        if responses
-                            .try_send(Response::RxPacket {
-                                rssi: pkt_status.rssi,
-                                snr: pkt_status.snr,
-                                payload,
-                            })
-                            .is_err()
-                        {
-                            warn!("RX packet dropped: response channel full");
-                        }
-
-                        if let Err(e) = start_rx(&mut lora, &cfg).await {
-                            warn!("restart RX failed: {}", e);
-                            state.state = RadioState::Idle;
-                            status.sender().send(state.clone());
-                            let _ = responses.try_send(Response::Error(ErrorCode::RadioBusy));
-                        }
-                    }
-                    Err(e) => {
-                        warn!("RX error: {}", e);
-                        if start_rx(&mut lora, &cfg).await.is_err() {
-                            state.state = RadioState::Idle;
-                            status.sender().send(state.clone());
-                            let _ = responses.try_send(Response::Error(ErrorCode::RadioBusy));
-                        }
-                    }
-                },
-                Either::Second(cmd) => {
-                    handle_cmd(cmd, &mut lora, &mut state, responses, status).await;
-                }
-            }
-        } else {
-            let cmd = commands.receive().await;
-            handle_cmd(cmd, &mut lora, &mut state, responses, status).await;
-        }
-    }
+    // `run()` under the embassy feature requires a bound channel even when
+    // no external task injects events. Radio inputs come from the root
+    // `during: next_command(commands)` activity and from internal durings;
+    // this static is kept solely to satisfy the constructor.
+    static RADIO_INTERNAL_CH: Channel<CriticalSectionRawMutex, RadioInput, 8> = Channel::new();
+    let mut machine = Radio::new(ctx, &RADIO_INTERNAL_CH);
+    #[cfg(feature = "debug-checkpoint")]
+    crate::debug_blink::set(3);
+    let _ = machine.run().await;
 }

-// ── Command handler ─────────────────────────────────────────────────
-
-async fn handle_cmd(
-    cmd: Command,
-    lora: &mut Radio,
-    state: &mut RadioStatus,
-    responses: &ResponseChannel,
-    status: &StatusWatch,
-) {
-    match cmd {
-        Command::Ping => {
+/// Init-failure fallback. Answers Ping; everything else errors.
+async fn degraded_loop(commands: &CommandChannel, responses: &ResponseChannel) {
+    loop {
+        let cmd = commands.receive().await;
+        if let Command::Ping = cmd {
            responses.send(Response::Pong).await;
-        }
-        Command::GetConfig => {
-            if let Some(cfg) = state.config {
-                responses.send(Response::Config(cfg)).await;
-            } else {
-                responses
-                    .send(Response::Error(ErrorCode::NotConfigured))
-                    .await;
-            }
-        }
-        Command::SetConfig(cfg) => {
-            if let Err(reason) = cfg.validate(Board::TX_POWER_RANGE) {
-                warn!("SetConfig rejected: {}", reason);
-                responses
-                    .send(Response::Error(ErrorCode::InvalidConfig))
-                    .await;
-            } else {
-                // Resolve TX_POWER_MAX sentinel to board's actual max
-                state.config = Some(cfg.resolve(Board::TX_POWER_RANGE));
-                status.sender().send(state.clone());
-                responses.send(Response::Ok).await;
-            }
-        }
-        Command::StartRx => {
-            if let Some(cfg) = state.config {
-                match start_rx(lora, &cfg).await {
-                    Ok(()) => {
-                        state.state = RadioState::Receiving;
-                        status.sender().send(state.clone());
-                        responses.send(Response::Ok).await;
-                    }
-                    Err(e) => {
-                        warn!("StartRx failed: {}", e);
-                        responses
-                            .send(Response::Error(ErrorCode::InvalidConfig))
-                            .await;
-                    }
-                }
-            } else {
-                responses
-                    .send(Response::Error(ErrorCode::NotConfigured))
-                    .await;
-            }
-        }
-        Command::StopRx => {
-            // Best-effort: if standby fails, radio is in unknown state
-            // but there's nothing useful we can do except continue.
-            let _ = lora.enter_standby().await;
-            state.state = RadioState::Idle;
-            status.sender().send(state.clone());
-            // try_send: StopRx may be sent internally on USB disconnect
-            // when the host isn't draining responses.
-            let _ = responses.try_send(Response::Ok);
-        }
-        Command::DisplayOn | Command::DisplayOff | Command::GetMac => {}
-        Command::Transmit { config, payload } => {
-            let tx_config = config
-                .map(|c| c.resolve(Board::TX_POWER_RANGE))
-                .or(state.config);
-            if let Some(cfg) = tx_config {
-                if let Err(reason) = cfg.validate(Board::TX_POWER_RANGE) {
-                    warn!("TX config rejected: {}", reason);
-                    responses
-                        .send(Response::Error(ErrorCode::InvalidConfig))
-                        .await;
-                    return;
-                }
-
-                let was_receiving = state.state == RadioState::Receiving;
-                state.state = RadioState::Transmitting;
-                status.sender().send(state.clone());
-
-                match do_tx(lora, &cfg, &payload).await {
-                    Ok(()) => {
-                        state.tx_count = state.tx_count.wrapping_add(1);
-                        responses.send(Response::TxDone).await;
-                    }
-                    Err(e) => {
-                        warn!("TX failed: {}", e);
-                        responses.send(Response::Error(ErrorCode::TxTimeout)).await;
-                    }
-                }
-
-                // Restore previous state. If we were receiving, restart RX
-                // using the stored config — NOT the per-packet TX override.
-                state.state = if was_receiving {
-                    // state.config is always Some when was_receiving (invariant).
-                    let rx_cfg = state.config.unwrap_or(cfg);
-                    match start_rx(lora, &rx_cfg).await {
-                        Ok(()) => RadioState::Receiving,
-                        Err(e) => {
-                            warn!("post-TX RX restart failed: {}", e);
-                            RadioState::Idle
-                        }
-                    }
-                } else {
-                    RadioState::Idle
-                };
-                status.sender().send(state.clone());
-            } else {
-                responses
-                    .send(Response::Error(ErrorCode::NotConfigured))
-                    .await;
-            }
+        } else {
+            responses
+                .send(Response::Error(ErrorCode::InvalidConfig))
+                .await;
        }
    }
 }
@@ -321,15 +642,14 @@ fn to_cr(cr: u8) -> lora_phy::mod_params::CodingRate {
    }
 }

-/// Create modulation parameters from a validated config.
 fn modulation_params(
-    lora: &mut Radio,
+    lora: &mut LoRaDriver,
    cfg: &RadioConfig,
 ) -> Result<lora_phy::mod_params::ModulationParams, RadioError> {
    lora.create_modulation_params(to_sf(cfg.sf), to_bw(cfg.bw), to_cr(cfg.cr), cfg.freq_hz)
 }

-async fn start_rx(lora: &mut Radio, cfg: &RadioConfig) -> Result<(), RadioError> {
+async fn start_rx(lora: &mut LoRaDriver, cfg: &RadioConfig) -> Result<(), RadioError> {
    let mdltn = modulation_params(lora, cfg)?;
    let pkt = lora.create_rx_packet_params(
        cfg.preamble_len,
@@ -342,37 +662,19 @@ async fn start_rx(lora: &mut Radio, cfg: &RadioConfig) -> Result<(), RadioError>
    lora.prepare_for_rx(RxMode::Continuous, &mdltn, &pkt).await
 }

-async fn rx_once(
-    lora: &mut Radio,
-    cfg: &RadioConfig,
-    buf: &mut [u8],
-) -> Result<(u8, lora_phy::mod_params::PacketStatus), RadioError> {
-    let mdltn = modulation_params(lora, cfg)?;
-    let pkt = lora.create_rx_packet_params(
-        cfg.preamble_len,
-        IMPLICIT_HEADER,
-        MAX_PAYLOAD as u8,
-        CRC_ON,
-        IQ_INVERTED,
-        &mdltn,
-    )?;
-    lora.rx(&pkt, buf).await
-}
-
-/// Maximum CAD attempts before transmitting anyway.
 const CAD_MAX_RETRIES: u8 = 10;

-async fn do_tx(lora: &mut Radio, cfg: &RadioConfig, payload: &[u8]) -> Result<(), RadioError> {
+async fn do_tx(lora: &mut LoRaDriver, cfg: &RadioConfig, payload: &[u8]) -> Result<(), RadioError> {
    let mdltn = modulation_params(lora, cfg)?;

-    // Listen-before-talk: check channel is clear before transmitting.
    if cfg.cad_enabled() {
+        #[cfg(feature = "debug-checkpoint")]
+        crate::debug_blink::set(7);
        lora.prepare_for_cad(&mdltn).await?;
        for _ in 0..CAD_MAX_RETRIES {
            if !lora.cad(&mdltn).await? {
-                break; // Channel is clear
+                break;
            }
-            // Channel busy — wait briefly and retry
            embassy_time::Timer::after_millis(10).await;
            lora.prepare_for_cad(&mdltn).await?;
        }
@@ -385,7 +687,11 @@ async fn do_tx(lora: &mut Radio, cfg: &RadioConfig, payload: &[u8]) -> Result<()
        IQ_INVERTED,
        &mdltn,
    )?;
+    #[cfg(feature = "debug-checkpoint")]
+    crate::debug_blink::set(8);
    lora.prepare_for_tx(&mdltn, &mut tx_pkt, cfg.tx_power_dbm as i32, payload)
        .await?;
+    #[cfg(feature = "debug-checkpoint")]
+    crate::debug_blink::set(9);
    lora.tx().await
 }
Author	SHA1	Message	Date
swaits	a0b15ddcaa	chore: release v0.5.0	2026-04-16 13:30:52 -06:00
swaits	388d07e90f	refactor: complete hsmc conversion and add debug-checkpoint feature Finishes the hsmc migration that was staged across the prior two commits: - Radio task is now a single `machine.run().await`; all I/O lives in state-scoped `during:` activities (`next_command`, `next_packet`, `perform_tx`). The old `push/drain` helpers, the imperative top-level `select`, `handle_cmd`, `handle_rx_result`, and `execute_transmit` are gone. `StartingRx` / `ResumingRx` intermediate states model the host-visible difference between a responding and a silent RX re-arm. - Host/USB task is now an hsmc statechart (Disconnected/Connected) with entry/exit actions handling display wake, radio StopRx, and display reset — replacing the open-coded `was_connected` edge detector. The `protocol_loop` keeps its imperative read path because `read_packet` blocks. - New `debug-checkpoint` cargo feature ships a dedicated `debug_blink.rs` task and a shared atomic counter that code along the boot/dispatch/TX path bumps at notable points. A ladder-latching write policy preserves the deepest TX phase reached on the first attempt until reboot — diagnostic output for UART-only boards where defmt would corrupt the host protocol. Zero footprint when the feature is off. - Silence a stray `clippy::unit_arg` on `led_off` / `led_blip` in the display task for boards with `LedDriver = ()`.	2026-04-16 13:28:44 -06:00
swaits	c6ef9559ec	refactor: drive radio task via hsmc statechart Replaces the imperative Mode enum + if-branches in the radio loop with a declarative hsmc statechart mirroring the display: Radio ├── Unconfigured └── Configured ├── Idle ├── Receiving └── Transmitting ├── FromIdle └── FromRx The `TransmittingFrom{Idle,Rx}` substates encode "where to return after TX" as state identity, killing the `was_receiving` bookkeeping. Entry actions announce `RadioEvent`s on the display channel; RF I/O stays in the task loop because `rx_once` blocks indefinitely and cannot live inside an action. Radio-init failure runs a Ping-only degraded loop without ever instantiating the machine.	2026-04-16 13:26:23 -06:00
swaits	596bc3ed96	refactor: drive display via hsmc statechart Replaces the ad-hoc display loop with a declarative hsmc statechart (Off/On.{Splash.{LearnMore,Info}, Dashboard.{Listening,Transmitting}}) and swaps the Radio→Display channel from a RadioStatus watch to a typed RadioEvent queue. The radio task now emits discrete mode and packet events instead of publishing full status snapshots; the display consumes them through the statechart, which also handles the 5 s splash alternation and 1 s sparkline tick via `on(after …)` / `on(every …)` transitions. Also: - Add hsmc dep and embassy/tokio feature shims (hsmc proc macro evaluates `cfg(feature = "embassy")` in this crate). - Fix USB disconnect path in `host/usb.rs` so the DTR branch always runs on read error (was early-continuing, starving display/radio reset).	2026-04-16 13:26:04 -06:00
swaits	272abceedb	refactor: consume donglora-protocol as a path dep Pulls the wire protocol types and COBS framing out of firmware and into the sibling ../protocol crate so client-rs, mux-rs, and bridge can share them. Firmware's src/protocol.rs is now a thin re-export shim preserving every crate::protocol::\* call site; src/host/framing.rs drops the in-tree CobsDecoder / cobs_encode_response and re-exports the codec, keeping only route_command (which needs embassy channels). All seven board features still build clean, cargo fmt clean, cargo test green.	2026-04-16 13:25:20 -06:00
swaits	f9582c0b94	style: cargo fmt	2026-04-16 13:25:19 -06:00
swaits	649c29218c	docs: add BLE soft-mesh multiplexer design doc	2026-04-16 13:24:37 -06:00
swaits	fd4e180879	chore: release v0.4.0	2026-04-11 22:35:33 -06:00
swaits	8b549d49a9	feat: add ELECROW ThinkNode-M2 board support ESP32-S3 + SX1262 + 1.3" SH1106 OLED + CP2102 UART bridge + 1000 mAh Li-Po. Pin map verified against Meshtastic's variants/esp32s3/ELECROW-ThinkNode-M2. DIO3 TCXO at 3.3 V (vs 1.8 V on Heltec), VEXT_ENABLE active HIGH (opposite polarity), dedicated LORA_POWER_EN on GPIO48 sequenced before SPI init. Reuses the existing async SH1106 driver at I2C address 0x3C. Refactors hal::esp32s3::{init_spi,init_i2c} and board::esp32s3::init_radio to accept generic GPIO bounds so ESP32-S3 boards with different pin assignments can share the helpers. init_radio now takes a TcxoCtrlVoltage parameter instead of hardcoding Ctrl1V8. Incidental cleanups needed to make `just check-all` green: - Replace the core::mem::forget(output) pattern with let _foo = ...; current esp-hal makes Output non-Drop, so forget is a no-op that trips clippy's forget_non_drop lint. - Switch justfile xtensa builds from `cargo +nightly` with a RUSTC override to `cargo +esp` so the compiler and rust-src versions stay aligned. Public nightly's rust-src had drifted two months ahead of the esp fork and broke -Zbuild-std on core.	2026-04-11 22:29:04 -06:00
swaits	7184610eea	feat: migrate to embassy-executor 0.10 Bump embassy-executor 0.9 -> 0.10 and embassy-rp 0.9 -> 0.10 from crates.io. Patch esp-hal, esp-rtos, esp-backtrace, esp-println from esp-rs/esp-hal main branch (esp-rtos 0.2.0 on crates.io pins embassy-executor ^0.9). API migrations: - embassy-executor: arch-cortex-m -> platform-cortex-m feature rename - embassy-executor: SpawnToken now returned as Result from task functions - esp-hal main: efuse::Efuse::mac_address() -> efuse::base_mac_address() - esp-hal main: esp_rtos::start() now requires SoftwareInterrupt<0> - embassy-rp 0.10: SPI constructor requires DMA interrupt bindings Also fixes UART display stuck on splash (sent Reset instead of On at boot) and switches just check to clippy -D warnings.	2026-04-11 02:34:04 -06:00
swaits	46822c182c	feat: add Waveshare RP2040-LoRa board support First RP2040 board and third MCU family (after ESP32-S3 and nRF52840). Hardware: RP2040 + SX1262 radio, 850-930 MHz HF, PE4259 antenna switch, LED on GPIO25, no OLED, USB-C via FPC ribbon cable to adapter board. New files: - src/hal/rp2040.rs: MCU primitives (SPI bus, USB driver, flash unique ID MAC) - src/board/waveshare_rp2040_lora.rs: board implementation - ld/rp2040-memory.x: linker memory layout Also fixes cortex-m-rt/set-vtor (moved from global dep to per-board feature, since Cortex-M0+ has no VTOR register) and makes build.rs memory.x selection target-aware.	2026-04-10 16:05:08 -06:00
swaitsandClaude Opus 4.6	2b7aacdb99	docs: fix stale path reference in changelog clients/python/ → donglora on PyPI Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>	2026-04-08 13:46:12 -06:00
swaitsandClaude Opus 4.6	cabc8c1cc0	feat: add espflash save-image for Xtensa boards Generate .bin firmware images for ESP32 boards alongside .elf, matching the existing .hex/.uf2 flow for nRF52840 boards. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>	2026-04-08 13:34:25 -06:00
swaits	0cbf59765c	docs: add missing LICENSE file	2026-04-07 19:52:52 -06:00