chore: release 1.1.0

The 1.0 Python client, mirroring the Rust client 1.0 API and the DongLoRa Protocol v2 wire format.

* Module split: monolithic protocol.py / client.py replaced with dongle.py (high-level async Dongle), session.py (reader task + tag routing), frame.py (streaming FrameDecoder + encode_frame), commands.py / events.py / errors.py / modulation.py / info.py / crc.py / chip_id (re-export) matching the donglora-protocol Rust crate.

* Async API throughout. Serial I/O via asyncio-serial; mux connections via asyncio streams. The blocking client surface is gone.

* thiserror-equivalent error hierarchy (DongloraError base with Timeout, TransportClosed, ReaderExited, BadFrame, ErrClientError variants mirroring the Rust ClientError).

* Tag-aware dispatch with concurrent in-flight commands: TagAllocator hands out 16-bit device tags, Session routes each response back to the originating coroutine.

* Auto-recovery from ERR(ENOTCONFIGURED): the Dongle caches the last SET_CONFIG and silently re-applies on timeout.

* 500 ms background keepalive task per PROTOCOL.md §3.4.

* Tests rewritten: test_dongle, test_session, test_frame, test_events, test_modulation, test_crc, test_ergonomics; old test_client / test_protocol removed.

* Sticky mux reconnect (from the prior fix commit) is preserved: once a mux socket is in use, reconnects commit to it instead of falling back to USB.

CHANGELOG.md

@@ -1,5 +1,81 @@
 # Changelog
 
+## 1.1.0 — 2026-04-23
+
+### Added
+
+- `connect()` now validates and auto-adjusts the requested
+  `LoRaConfig` against the device's advertised caps (`GET_INFO`):
+  - `tx_power_dbm` is silently clamped into
+    `[tx_power_min_dbm, tx_power_max_dbm]`. A clamp is logged at
+    INFO. This keeps `dl.connect(config=my_config)` "just work" on
+    boards with lower PA ceilings (e.g. SX1276 @ 20 dBm vs SX1262
+    @ 22 dBm) without any per-board bookkeeping by the caller.
+  - `freq_hz` outside the device's range, `sf` not in
+    `supported_sf_bitmap`, or `bw` not in `supported_bw_bitmap` now
+    raise :class:`ConfigNotSupported` *before* `SET_CONFIG` hits
+    the wire. Silent shifts here would cross regulatory boundaries
+    or change airtime/sensitivity without the caller noticing.
+  - `Dongle.config` is now populated from `SetConfigResult.current`
+    — the modulation the device actually stored, post-clamp — so
+    callers can inspect what landed.
+- New `ConfigNotSupported` exception (subclass of `DongloraError`),
+  exported at the package root.
+
+## 1.0.1 — 2026-04-22
+
+### Fixed
+
+- `discovery.find_port` / `wait_for_device` now match the WCH CH340K
+  USB-UART bridge (`1a86:7522`) in `BRIDGE_VID_PIDS`. The Elecrow
+  ThinkNode-M2 board ships with a CH340K bridge; the previous set
+  covered CP2102, CH9102, standard CH340, and FTDI but missed this
+  specific revision, so `discovery` returned `None` on that board.
+
+## 1.0.0 — 2026-04-22
+
+The 1.0 Python client, mirroring the Rust client 1.0 API and the
+DongLoRa Protocol v2 wire format.
+
+### Breaking
+
+- **DongLoRa Protocol v2 wire format** (wire-incompatible with 0.x
+  firmware and clients). All message types, tag correlation, and
+  framing now follow `PROTOCOL.md` v1.0.
+- **Module split.** Monolithic `protocol.py` / `client.py` are replaced
+  with: `dongle.py` (high-level async `Dongle`), `session.py` (reader
+  task, tag routing, keepalive), `frame.py` (streaming `FrameDecoder`
+  + `encode_frame`), `commands.py` / `events.py` / `errors.py` /
+  `modulation.py` / `info.py` / `crc.py`, matching the
+  `donglora-protocol` Rust crate module-for-module.
+- **Async API throughout.** Serial I/O via `asyncio-serial`; mux
+  connections via `asyncio` streams. The blocking client surface is
+  gone.
+- **New error hierarchy.** `DongloraError` base with `Timeout`,
+  `TransportClosed`, `ReaderExited`, `BadFrame`, and `ErrClient...`
+  variants mirroring the Rust client's `ClientError`.
+
+### Added
+
+- Tag-aware dispatch with concurrent in-flight commands. The
+  `TagAllocator` hands out 16-bit device tags; `Session` routes each
+  response back to the originating coroutine.
+- Auto-recovery from `ERR(ENOTCONFIGURED)`. The `Dongle` caches the
+  last `SET_CONFIG` and silently re-applies it on timeout, retrying
+  once.
+- 500 ms background keepalive task per `PROTOCOL.md §3.4`.
+- Sticky mux reconnect: once a mux connection succeeds, all future
+  `connect()` calls in the same process only try the mux (waiting
+  for it to reappear if needed). `try_connect()` raises immediately
+  so callers can retry with backoff. Prevents clients from stealing
+  the serial port during mux restarts.
+
+### Test suite
+
+- New tests: `test_dongle`, `test_session`, `test_frame`, `test_events`,
+  `test_modulation`, `test_crc`, `test_ergonomics`.
+- Removed: `test_client`, `test_protocol` (superseded).
+
 ## 0.2.0 — 2026-04-08
 
 ### Features

donglora/__init__.py

@@ -1,30 +1,48 @@
-"""DongLoRa host library — connect, configure, send/receive LoRa packets.
-
-Implements the DongLoRa USB protocol (COBS-framed fixed-size LE).
-See firmware/PROTOCOL.md for the full specification.
+"""DongLoRa host library — talk LoRa from Python in three lines.
 
 Quick start::
 
     import donglora as dl
 
-    ser = dl.connect()
-    dl.send(ser, "SetConfig", config=dl.DEFAULT_CONFIG)
-    dl.send(ser, "StartRx")
+    d = dl.connect()                  # auto-discover, auto-configure, auto-keepalive
+    d.tx(b"Hello")                    # blocks until TX_DONE
+    for pkt in d.rx():                # continuous receive
+        print(pkt.rssi_dbm, pkt.data)
 
-    while True:
-        pkt = dl.recv(ser)
-        if pkt:
-            print(pkt["rssi"], pkt["payload"].hex())
+For trivial scripts, skip the handle::
+
+    import donglora as dl
+    dl.tx(b"hi")
+    for pkt in dl.rx():
+        ...
+
+Customise anything via :func:`connect` kwargs:
+
+* ``port="/dev/ttyUSB0"`` — explicit serial device
+* ``config=LoRaConfig(...)`` — override the default radio config
+* ``auto_configure=False`` — skip automatic SET_CONFIG
+* ``keepalive=False`` — run your own session-liveness cadence
+
+The full DongLoRa Protocol v2 surface is available via :class:`Dongle` methods
+(:meth:`Dongle.tx` / :meth:`Dongle.rx` / :meth:`Dongle.set_config` /
+:meth:`Dongle.ping` / :attr:`Dongle.info`) and the underlying
+:mod:`donglora.frame` / :mod:`donglora.events` / :mod:`donglora.info`
+modules if you need to speak the wire directly.
+
+See ``firmware/PROTOCOL.md`` for the wire-level specification.
 """
 
-from donglora.client import (
-    HANDSHAKE_TIMEOUT,
-    drain_rx,
-    recv,
-    send,
-    validate,
+from __future__ import annotations
+
+from donglora._top_level import close, recv, rx, tx
+from donglora.commands import (
+    TYPE_GET_INFO,
+    TYPE_PING,
+    TYPE_RX_START,
+    TYPE_RX_STOP,
+    TYPE_SET_CONFIG,
+    TYPE_TX,
 )
-from donglora.codec import cobs_encode, read_frame
 from donglora.connect import (
     DEFAULT_TIMEOUT,
     connect,
@@ -43,101 +61,130 @@ from donglora.discovery import (
     find_port,
     wait_for_device,
 )
-from donglora.protocol import (
-    CMD_TAG_GET_CONFIG,
-    CMD_TAG_GET_MAC,
-    CMD_TAG_PING,
-    CMD_TAG_SET_CONFIG,
-    CMD_TAG_START_RX,
-    CMD_TAG_STOP_RX,
-    CMD_TAG_TRANSMIT,
-    DEFAULT_CONFIG,
-    ERROR_INVALID_CONFIG,
-    ERROR_NO_DISPLAY,
-    ERROR_NOT_CONFIGURED,
-    ERROR_RADIO_BUSY,
-    ERROR_TX_TIMEOUT,
-    MAX_PAYLOAD,
-    PREAMBLE_DEFAULT,
-    RADIO_CONFIG_SIZE,
-    RESP_TAG_CONFIG,
-    RESP_TAG_ERROR,
-    RESP_TAG_MAC_ADDRESS,
-    RESP_TAG_OK,
-    RESP_TAG_PONG,
-    RESP_TAG_RX_PACKET,
-    RESP_TAG_TX_DONE,
-    TX_POWER_MAX,
-    Bandwidth,
+from donglora.dongle import Dongle
+from donglora.errors import (
+    BusyError,
+    Cancelled,
+    ChannelBusy,
+    ConfigNotSupported,
+    DeviceError,
+    DongloraError,
     ErrorCode,
-    RadioConfig,
-    decode_config,
-    decode_response,
-    encode_command,
-    encode_config,
+    FrameError,
+    InternalError,
+    LengthError,
+    ModulationError,
+    NotConfiguredError,
+    ParamError,
+    RadioError,
+    TimeoutError_,
+    UnknownCommandError,
+)
+from donglora.events import (
+    Owner,
+    RxEvent,
+    RxOrigin,
+    SetConfigResult,
+    SetConfigResultCode,
+    TxDone,
+    TxResult,
+)
+from donglora.frame import MAX_OTA_PAYLOAD, MAX_PAYLOAD_FIELD, MAX_WIRE_FRAME, Frame, encode_frame
+from donglora.info import MAX_MCU_UID_LEN, MAX_RADIO_UID_LEN, Capability, Info, RadioChipId
+from donglora.modulation import (
+    FlrcBitrate,
+    FlrcBt,
+    FlrcCodingRate,
+    FlrcConfig,
+    FlrcPreambleLen,
+    FskConfig,
+    LoRaBandwidth,
+    LoRaCodingRate,
+    LoRaConfig,
+    LoRaHeaderMode,
+    LrFhssBandwidth,
+    LrFhssCodingRate,
+    LrFhssConfig,
+    LrFhssGrid,
+    Modulation,
+    ModulationId,
 )
 from donglora.transport import MuxConnection
 
 __all__ = [
     "BRIDGE_VID_PIDS",
-    "CMD_TAG_GET_CONFIG",
-    "CMD_TAG_GET_MAC",
-    # tag constants
-    "CMD_TAG_PING",
-    "CMD_TAG_SET_CONFIG",
-    "CMD_TAG_START_RX",
-    "CMD_TAG_STOP_RX",
-    "CMD_TAG_TRANSMIT",
-    "DEFAULT_CONFIG",
-    # connect
     "DEFAULT_TIMEOUT",
-    # error constants
-    "ERROR_INVALID_CONFIG",
-    "ERROR_NOT_CONFIGURED",
-    "ERROR_NO_DISPLAY",
-    "ERROR_RADIO_BUSY",
-    "ERROR_TX_TIMEOUT",
-    # client
-    "HANDSHAKE_TIMEOUT",
-    # protocol
-    "MAX_PAYLOAD",
-    "PREAMBLE_DEFAULT",
-    "RADIO_CONFIG_SIZE",
-    "RESP_TAG_CONFIG",
-    "RESP_TAG_ERROR",
-    "RESP_TAG_MAC_ADDRESS",
-    "RESP_TAG_OK",
-    "RESP_TAG_PONG",
-    "RESP_TAG_RX_PACKET",
-    "RESP_TAG_TX_DONE",
-    "TX_POWER_MAX",
+    "MAX_MCU_UID_LEN",
+    "MAX_OTA_PAYLOAD",
+    "MAX_PAYLOAD_FIELD",
+    "MAX_RADIO_UID_LEN",
+    "MAX_WIRE_FRAME",
+    "TYPE_GET_INFO",
+    "TYPE_PING",
+    "TYPE_RX_START",
+    "TYPE_RX_STOP",
+    "TYPE_SET_CONFIG",
+    "TYPE_TX",
     "USB_PID",
-    # discovery
     "USB_VID",
     "USB_VID_PID",
-    "Bandwidth",
+    "BusyError",
+    "Cancelled",
+    "Capability",
+    "ChannelBusy",
+    "ConfigNotSupported",
+    "DeviceError",
+    "Dongle",
+    "DongloraError",
     "ErrorCode",
-    # transport
+    "FlrcBitrate",
+    "FlrcBt",
+    "FlrcCodingRate",
+    "FlrcConfig",
+    "FlrcPreambleLen",
+    "Frame",
+    "FrameError",
+    "FskConfig",
+    "Info",
+    "InternalError",
+    "LengthError",
+    "LoRaBandwidth",
+    "LoRaCodingRate",
+    "LoRaConfig",
+    "LoRaHeaderMode",
+    "LrFhssBandwidth",
+    "LrFhssCodingRate",
+    "LrFhssConfig",
+    "LrFhssGrid",
+    "Modulation",
+    "ModulationError",
+    "ModulationId",
     "MuxConnection",
-    "RadioConfig",
-    # codec
-    "cobs_encode",
+    "NotConfiguredError",
+    "Owner",
+    "ParamError",
+    "RadioChipId",
+    "RadioError",
+    "RxEvent",
+    "RxOrigin",
+    "SetConfigResult",
+    "SetConfigResultCode",
+    "TimeoutError_",
+    "TxDone",
+    "TxResult",
+    "UnknownCommandError",
+    "close",
     "connect",
     "connect_default",
     "connect_mux_auto",
-    "decode_config",
-    "decode_response",
     "default_socket_path",
-    "drain_rx",
-    "encode_command",
-    "encode_config",
+    "encode_frame",
     "find_port",
     "mux_connect",
     "mux_tcp_connect",
-    "read_frame",
     "recv",
-    "send",
+    "rx",
     "try_connect",
-    "validate",
+    "tx",
     "wait_for_device",
 ]

donglora/_top_level.py

@@ -0,0 +1,70 @@
+"""Module-level convenience singletons so ``import donglora as dl`` gives
+one-line TX / RX scripts a Dongle without any explicit setup.
+
+.. code-block:: python
+
+    import donglora as dl
+
+    dl.tx(b"hello")                 # lazy auto-connect on first call
+    for pkt in dl.rx():             # same — lazy auto-connect
+        print(pkt.rssi_dbm, pkt.data)
+
+Users who need multiple connections, explicit configs, or context-manager
+lifetimes should call :func:`donglora.connect` directly and use the
+returned :class:`Dongle`.
+"""
+
+from __future__ import annotations
+
+import atexit
+import contextlib
+import threading
+from collections.abc import Iterator
+
+from donglora.dongle import Dongle
+from donglora.events import RxEvent, TxDone
+
+_default: Dongle | None = None
+_lock = threading.Lock()
+
+
+def _get_default() -> Dongle:
+    """Return (lazily creating) the process-wide default :class:`Dongle`."""
+    global _default
+    with _lock:
+        if _default is None:
+            from donglora.connect import connect
+
+            _default = connect()
+            atexit.register(_cleanup)
+        return _default
+
+
+def _cleanup() -> None:
+    global _default
+    with _lock:
+        d = _default
+        _default = None
+    if d is not None:
+        with contextlib.suppress(Exception):
+            d.close()
+
+
+def tx(data: bytes, *, skip_cad: bool = False, timeout: float = 10.0) -> TxDone:
+    """One-line transmit. Creates the default dongle on first call."""
+    return _get_default().tx(data, skip_cad=skip_cad, timeout=timeout)
+
+
+def rx(timeout: float | None = None) -> Iterator[RxEvent]:
+    """One-line continuous receive. Lazy-connects on first call."""
+    return iter(_get_default().rx(timeout))
+
+
+def recv(timeout: float | None = None) -> RxEvent | None:
+    """One packet. Lazy-connects on first call."""
+    return _get_default().recv(timeout)
+
+
+def close() -> None:
+    """Close the default dongle, if any. Safe to call multiple times."""
+    _cleanup()

donglora/client.py

@@ -1,108 +0,0 @@
-"""High-level DongLoRa client helpers.
-
-Mirrors the Rust client's ``client.rs``.  Provides :func:`send`,
-:func:`recv`, :func:`drain_rx`, and :func:`validate` as module-level
-functions that operate on any transport (serial port or mux connection).
-"""
-
-from __future__ import annotations
-
-import collections
-from typing import Any
-
-from donglora.codec import cobs_encode, read_frame
-from donglora.protocol import decode_response, encode_command
-
-RX_BUFFER_CAP: int = 256
-"""Maximum number of buffered RxPackets before oldest are dropped."""
-
-MAX_UNSOLICITED_BEFORE_TIMEOUT: int = 50
-"""Safety bound: max frames to read while waiting for a solicited response."""
-
-HANDSHAKE_TIMEOUT: float = 0.2
-"""Timeout (seconds) for the ping-on-connect handshake."""
-
-_rx_queue: collections.deque[dict[str, Any]] = collections.deque(maxlen=RX_BUFFER_CAP)
-"""Buffer for RxPacket frames encountered while waiting for solicited responses."""
-
-
-def validate(ser: Any) -> None:
-    """Ping the device and verify the Pong response.
-
-    Uses a short timeout to fail fast on non-DongLoRa devices.  Called
-    automatically by the ``connect`` family of functions.
-
-    Raises :class:`ConnectionError` if the device does not respond.
-    """
-    saved = ser.timeout
-    ser.timeout = HANDSHAKE_TIMEOUT
-    try:
-        resp = send(ser, "Ping")
-        if resp["type"] != "Pong":
-            raise ConnectionError(f"device did not respond to ping — got {resp['type']}")
-    except ConnectionError:
-        raise
-    except Exception as exc:
-        raise ConnectionError("device did not respond to ping — not a DongLoRa device") from exc
-    finally:
-        ser.timeout = saved
-
-
-def send(ser: Any, cmd: str, **kwargs: Any) -> dict[str, Any]:
-    """Send a command and return the solicited response.
-
-    Any unsolicited ``RxPacket`` frames encountered while waiting are
-    buffered in the module-level receive queue (retrievable via
-    :func:`recv` / :func:`drain_rx`).
-    """
-    ser.write(cobs_encode(encode_command(cmd, **kwargs)))
-    ser.flush()
-    for _ in range(MAX_UNSOLICITED_BEFORE_TIMEOUT):
-        data = read_frame(ser)
-        if data is None:
-            return {"type": "Timeout"}
-        resp = decode_response(data)
-        if resp["type"] == "RxPacket":
-            _rx_queue.append(resp)
-            continue
-        return resp
-    return {"type": "Timeout"}
-
-
-def recv(ser: Any) -> dict[str, Any] | None:
-    """Return the next RxPacket from the buffer or the wire.
-
-    Returns ``None`` on timeout (no packet available).
-    """
-    if _rx_queue:
-        return _rx_queue.popleft()
-    data = read_frame(ser)
-    if data is None:
-        return None
-    resp = decode_response(data)
-    if resp["type"] == "RxPacket":
-        return resp
-    return None
-
-
-def drain_rx(ser: Any) -> list[dict[str, Any]]:
-    """Drain all buffered and pending RxPacket frames.
-
-    Temporarily reduces the read timeout to quickly drain any frames
-    still in flight, then restores the original timeout.
-    """
-    packets: list[dict[str, Any]] = list(_rx_queue)
-    _rx_queue.clear()
-    old_timeout = ser.timeout
-    ser.timeout = 0.01
-    try:
-        while True:
-            data = read_frame(ser)
-            if data is None:
-                break
-            resp = decode_response(data)
-            if resp["type"] == "RxPacket":
-                packets.append(resp)
-    finally:
-        ser.timeout = old_timeout
-    return packets

donglora/codec.py

@@ -1,44 +1,21 @@
-"""COBS framing for the DongLoRa USB protocol.
+"""Backwards-compatible COBS codec helpers.
 
-Mirrors the Rust client's ``codec.rs``.  Frames are COBS-encoded with a
-``0x00`` sentinel byte.
+The v1.0 wire layer lives in :mod:`donglora.frame`. This module keeps
+the thin helpers that the old client exposed (``cobs_encode``,
+``read_frame``) so unrelated transport glue keeps working.
 """
 
 from __future__ import annotations
 
-from typing import Protocol, runtime_checkable
-
 from cobs import cobs
 
-
-@runtime_checkable
-class Readable(Protocol):
-    """Anything with a blocking ``read(n)`` method (serial port, socket wrapper, etc.)."""
-
-    def read(self, n: int = 1) -> bytes: ...
+from donglora.frame import Frame, Readable, read_frame  # noqa: F401 — re-export
 
 
 def cobs_encode(data: bytes) -> bytes:
-    """COBS-encode *data* and append the ``0x00`` sentinel."""
-    return cobs.encode(data) + b"\x00"
+    """COBS-encode *data* and append the ``0x00`` sentinel.
 
-
-def read_frame(reader: Readable) -> bytes | None:
-    """Read one COBS frame from *reader*.
-
-    Returns decoded payload bytes, or ``None`` on timeout (zero-length read).
+    Exposed for transport-level pass-through; regular callers should go
+    through :func:`donglora.frame.encode_frame` instead.
     """
-    buf = b""
-    while True:
-        b = reader.read(1)
-        if not b:
-            return None
-        if b == b"\x00":
-            break
-        buf += b
-    if not buf:
-        return None
-    try:
-        return cobs.decode(buf)
-    except cobs.DecodeError:
-        return None
+    return cobs.encode(data) + b"\x00"

donglora/commands.py

@@ -0,0 +1,50 @@
+"""Host-to-device command payload encoders and type constants."""
+
+from __future__ import annotations
+
+import struct
+from dataclasses import dataclass
+
+from donglora.modulation import Modulation, encode_modulation
+
+# Message type identifiers (PROTOCOL.md §4)
+TYPE_PING: int = 0x01
+TYPE_GET_INFO: int = 0x02
+TYPE_SET_CONFIG: int = 0x03
+TYPE_TX: int = 0x04
+TYPE_RX_START: int = 0x05
+TYPE_RX_STOP: int = 0x06
+
+
+@dataclass(frozen=True)
+class TxFlags:
+    skip_cad: bool = False
+
+    def as_byte(self) -> int:
+        return 0b0000_0001 if self.skip_cad else 0
+
+
+def encode_ping_payload() -> bytes:
+    return b""
+
+
+def encode_get_info_payload() -> bytes:
+    return b""
+
+
+def encode_set_config_payload(modulation: Modulation) -> bytes:
+    return encode_modulation(modulation)
+
+
+def encode_tx_payload(data: bytes, *, skip_cad: bool = False) -> bytes:
+    if not data:
+        raise ValueError("TX payload must be non-empty")
+    return struct.pack("<B", TxFlags(skip_cad).as_byte()) + data
+
+
+def encode_rx_start_payload() -> bytes:
+    return b""
+
+
+def encode_rx_stop_payload() -> bytes:
+    return b""

donglora/connect.py

@@ -1,37 +1,51 @@
-"""Connection auto-detection and mux client helpers.
+"""Auto-detect and connect to a DongLoRa device.
 
-Mirrors the Rust client's ``connect.rs``.  The :func:`connect` function
-tries mux connections first (TCP via env var, then Unix socket), falling
-back to direct USB serial.  This matches the Rust client's ``connect()``
-behaviour.
+``connect()`` is the "60-seconds-to-hacking" entry point. In its zero-argument
+form it:
+
+1. Finds a DongLoRa USB device (or mux socket if one is available).
+2. Opens the transport at 115200 baud.
+3. Sends ``GET_INFO`` to confirm we're talking DongLoRa Protocol v2.
+4. Applies a sensible default :class:`LoRaConfig` via ``SET_CONFIG``,
+   auto-clamping ``tx_power_dbm`` against the device's advertised cap
+   and raising :class:`ConfigNotSupported` for out-of-range frequency,
+   spreading factor, or bandwidth.
+5. Spawns a keepalive thread to keep the session alive.
+6. Returns a :class:`Dongle` ready for ``.tx()`` / ``.rx()``. The
+   actually-applied config (post-clamp) is exposed on
+   :attr:`Dongle.config`.
+
+Every step is overrideable via keyword arguments. See ``connect``'s docstring.
 """
 
 from __future__ import annotations
 
+import dataclasses
 import logging
 import os
 import socket
+import time
 from typing import Any
 
 import serial
 
-from donglora.client import validate
 from donglora.discovery import find_port, wait_for_device
+from donglora.dongle import Dongle
+from donglora.errors import ConfigNotSupported, DongloraError
+from donglora.info import Info
+from donglora.modulation import LoRaConfig, Modulation
+from donglora.session import Session
 from donglora.transport import MuxConnection
 
-log = logging.getLogger("donglora")
+log = logging.getLogger("donglora.connect")
 
 DEFAULT_TIMEOUT: float = 2.0
-"""Default read timeout for connections (seconds)."""
+"""Default transport read timeout (seconds). This is the *poll* interval
+— overall command deadlines are per-call kwargs on the Dongle API."""
 
 
 def default_socket_path() -> str:
-    """Resolve the mux socket path in priority order.
-
-    1. ``$DONGLORA_MUX`` environment variable
-    2. ``$XDG_RUNTIME_DIR/donglora/mux.sock``
-    3. ``/tmp/donglora-mux.sock``
-    """
+    """Resolve the mux socket path in priority order."""
     env = os.environ.get("DONGLORA_MUX")
     if env:
         return env
@@ -42,7 +56,6 @@ def default_socket_path() -> str:
 
 
 def _find_mux_socket() -> str | None:
-    """Find an existing mux socket path, or ``None`` if no socket file exists."""
     env = os.environ.get("DONGLORA_MUX")
     if env:
         return env if os.path.exists(env) else None
@@ -55,11 +68,10 @@ def _find_mux_socket() -> str | None:
     return p if os.path.exists(p) else None
 
 
-def _try_tcp_mux(addr: str, timeout: float) -> MuxConnection | None:
-    """Try to connect to a TCP mux at *addr* (``[host:]port``).
+_used_mux = False
 
-    Returns ``None`` on failure instead of raising.
-    """
+
+def _try_tcp_mux(addr: str, timeout: float) -> MuxConnection | None:
     if ":" in addr:
         host, _, port_str = addr.rpartition(":")
         host = host or "localhost"
@@ -71,143 +83,323 @@ def _try_tcp_mux(addr: str, timeout: float) -> MuxConnection | None:
     except ValueError:
         return None
     try:
-        return mux_tcp_connect(host, port, timeout)
+        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        sock.connect((host, port))
+        return MuxConnection(sock, timeout)
     except (ConnectionRefusedError, OSError):
         return None
 
 
-# ── Public connection functions ───────────────────────────────────
+def _open_transport(port: str | None, timeout: float) -> Any:
+    """Bottom-level transport opener. Returns a serial/socket-like object.
 
-
-def mux_connect(path: str | None = None, timeout: float = DEFAULT_TIMEOUT) -> MuxConnection:
-    """Connect to the DongLoRa mux daemon via Unix domain socket."""
-    if path is None:
-        path = _find_mux_socket()
-    if path is None:
-        raise FileNotFoundError("no mux socket found")
-    sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
-    sock.connect(path)
-    conn = MuxConnection(sock, timeout)
-    validate(conn)
-    return conn
-
-
-def mux_tcp_connect(host: str, port: int, timeout: float = DEFAULT_TIMEOUT) -> MuxConnection:
-    """Connect to the DongLoRa mux daemon via TCP."""
-    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-    sock.connect((host, port))
-    conn = MuxConnection(sock, timeout)
-    validate(conn)
-    return conn
-
-
-def connect(port: str | None = None, timeout: float = DEFAULT_TIMEOUT) -> Any:
-    """Auto-detect and connect to a DongLoRa device.
-
-    Priority:
-
-    1. ``DONGLORA_MUX_TCP`` env var -> TCP mux connection
-    2. Unix socket mux (if socket file exists)
-    3. Direct USB serial (auto-detect by VID:PID, blocks until device appears)
-
-    If *port* is given, skips mux detection and connects directly.
-
-    .. note::
-
-       If a mux socket file exists, this function **commits** to the mux
-       and will raise on failure rather than falling through to USB serial.
-       This prevents port-stealing race conditions (matches Rust v0.2.1).
+    Priority: explicit port → sticky mux → TCP mux env → Unix mux socket → USB auto-detect.
     """
-    # Explicit port — go direct
+    global _used_mux
+
     if port is not None:
         log.debug("opening serial port %s", port)
         ser = serial.Serial(port, baudrate=115200, timeout=timeout)
         ser.reset_input_buffer()
-        validate(ser)
         return ser
 
-    # Try TCP mux via environment variable
+    if _used_mux:
+        mux_path = default_socket_path()
+        while not os.path.exists(mux_path):
+            log.info("Waiting for mux at %s ...", mux_path)
+            time.sleep(0.5)
+        sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+        sock.connect(mux_path)
+        return MuxConnection(sock, timeout)
+
     tcp = os.environ.get("DONGLORA_MUX_TCP")
     if tcp:
         conn = _try_tcp_mux(tcp, timeout)
         if conn is not None:
             log.debug("connected to TCP mux at %s", tcp)
+            _used_mux = True
             return conn
 
-    # Try Unix socket mux — commit if socket exists (no fall-through)
     sock_path = _find_mux_socket()
     if sock_path is not None:
-        log.debug("mux socket found at %s — connecting via mux only", sock_path)
-        return mux_connect(sock_path, timeout)
+        log.debug("mux socket found at %s", sock_path)
+        sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+        sock.connect(sock_path)
+        _used_mux = True
+        return MuxConnection(sock, timeout)
 
-    # Direct USB serial — only reached when no mux socket exists at all
     port_path = find_port()
     if port_path is None:
         port_path = wait_for_device()
     log.debug("opening serial port %s", port_path)
     ser = serial.Serial(port_path, baudrate=115200, timeout=timeout)
     ser.reset_input_buffer()
-    validate(ser)
     return ser
 
 
-def connect_default() -> Any:
-    """Connect with the default timeout.  Convenience wrapper for ``connect(None)``."""
-    return connect(timeout=DEFAULT_TIMEOUT)
+def _prepare_config(info: Info, config: Modulation) -> Modulation:
+    """Validate and auto-adjust *config* against the device's advertised caps.
 
+    Per-field policy:
 
-def connect_mux_auto(timeout: float = DEFAULT_TIMEOUT) -> Any:
-    """Connect to a mux daemon only (TCP via env var, then Unix socket).
+    * ``tx_power_dbm``: clamped into ``[tx_power_min_dbm, tx_power_max_dbm]``.
+      A clamp is logged at INFO — "give me max power" quietly returning less
+      is the universally-expected behavior and not worth a hard error.
+    * ``freq_hz``: rejected with :class:`ConfigNotSupported` when outside
+      ``[freq_min_hz, freq_max_hz]``. Silently shifting a 915 MHz request
+      to 868 MHz (or vice versa) would cross regulatory boundaries.
+    * ``sf``, ``bw``: rejected with :class:`ConfigNotSupported` when the
+      corresponding capability bit isn't set. These change airtime and
+      sensitivity dramatically; silent substitution is more confusing
+      than helpful.
 
-    Unlike :func:`connect`, this **never** falls back to direct USB serial.
-    Returns an error if no mux is reachable — the caller can retry with
-    backoff.
-
-    This is the Python equivalent of the Rust client's "sticky mux" behaviour:
-    once you decide to use the mux, you stay on the mux.
+    Non-LoRa modulations pass through untouched — the firmware rejects
+    unsupported modulation IDs with ``EMODULATION`` on its own.
     """
-    # Try TCP mux via environment variable
+    if not isinstance(config, LoRaConfig):
+        return config
+
+    cfg: LoRaConfig = config
+
+    if not (info.freq_min_hz <= cfg.freq_hz <= info.freq_max_hz):
+        raise ConfigNotSupported(
+            f"frequency {cfg.freq_hz} Hz outside device range "
+            f"[{info.freq_min_hz}, {info.freq_max_hz}] Hz"
+        )
+
+    if not (info.supported_sf_bitmap & (1 << cfg.sf)):
+        supported = [i for i in range(16) if info.supported_sf_bitmap & (1 << i)]
+        raise ConfigNotSupported(
+            f"SF{cfg.sf} not supported by this device (supports SF{supported})"
+        )
+
+    bw_bit = int(cfg.bw)
+    if not (info.supported_bw_bitmap & (1 << bw_bit)):
+        raise ConfigNotSupported(
+            f"bandwidth {cfg.bw.name} (bit {bw_bit}) not in "
+            f"supported_bw_bitmap 0x{info.supported_bw_bitmap:04X}"
+        )
+
+    if cfg.tx_power_dbm > info.tx_power_max_dbm:
+        log.info(
+            "clamping tx_power_dbm: requested %d dBm, device max %d dBm",
+            cfg.tx_power_dbm,
+            info.tx_power_max_dbm,
+        )
+        cfg = dataclasses.replace(cfg, tx_power_dbm=info.tx_power_max_dbm)
+    elif cfg.tx_power_dbm < info.tx_power_min_dbm:
+        log.info(
+            "clamping tx_power_dbm: requested %d dBm, device min %d dBm",
+            cfg.tx_power_dbm,
+            info.tx_power_min_dbm,
+        )
+        cfg = dataclasses.replace(cfg, tx_power_dbm=info.tx_power_min_dbm)
+
+    return cfg
+
+
+def connect(
+    port: str | None = None,
+    *,
+    timeout: float = DEFAULT_TIMEOUT,
+    config: Modulation | None = None,
+    auto_configure: bool = True,
+    keepalive: bool = True,
+) -> Dongle:
+    """Connect to a DongLoRa device and return a ready-to-use :class:`Dongle`.
+
+    The default (zero-argument) invocation:
+
+    * Auto-discovers a USB device (or mux socket).
+    * Sends ``GET_INFO`` to confirm DongLoRa Protocol v2.
+    * Applies ``LoRaConfig.default()`` (EU868 / SF7 / BW125 / CR4/5).
+    * Starts a background keepalive thread.
+
+    Parameters
+    ----------
+    port
+        Explicit serial device path. Skips auto-discovery.
+    timeout
+        Transport read timeout (polling interval). Default 2 s.
+    config
+        Modulation to apply at connect-time. Default:
+        :meth:`LoRaConfig.default`. Pass ``None`` with
+        ``auto_configure=False`` to skip configuration entirely.
+        With ``auto_configure=True`` (default), ``tx_power_dbm`` is
+        silently clamped to the device's ``tx_power_max_dbm`` /
+        ``tx_power_min_dbm``; out-of-range ``freq_hz``, ``sf``, or
+        ``bw`` raise :class:`ConfigNotSupported`. Inspect
+        :attr:`Dongle.config` after connect to see what the device
+        actually stored.
+    auto_configure
+        If False, skip the ``SET_CONFIG`` step entirely — no
+        validation, no clamping. The caller is then responsible for
+        calling :meth:`Dongle.set_config` before TX/RX.
+    keepalive
+        If False, skip the keepalive daemon thread. The caller is
+        responsible for periodic :meth:`Dongle.ping` calls to stay
+        under the 1 s inactivity timer.
+
+    """
+
+    def _open_and_init() -> tuple[Session, Info, Modulation | None]:
+        """Open the transport, bring up a Session, and verify+configure.
+
+        Used for both the initial connect and any later transparent
+        reconnect driven by :meth:`Dongle._recover_session`. Respects
+        the sticky-mux state at call time — so a mux-first first call
+        followed by a reconnect will stay on mux even if USB came back.
+        """
+        transport = _open_transport(port, timeout)
+        session = Session(transport)
+        try:
+            info = session.get_info(timeout=max(timeout, 2.0))
+        except DongloraError:
+            session.close()
+            raise
+        if not isinstance(info, Info):
+            session.close()
+            raise DongloraError(f"GET_INFO returned unexpected payload: {info!r}")
+        if info.proto_major != 1:
+            session.close()
+            raise DongloraError(
+                f"device speaks DongLoRa Protocol v{info.proto_major}.{info.proto_minor}; "
+                "this client requires v1.x",
+            )
+
+        applied: Modulation | None = None
+        if auto_configure:
+            requested: Modulation = config if config is not None else LoRaConfig.default()
+            try:
+                prepared = _prepare_config(info, requested)
+                result = session.set_config(prepared, timeout=max(timeout, 2.0))
+            except DongloraError:
+                session.close()
+                raise
+            # Firmware echoes back the modulation it actually stored. Trust
+            # that rather than our own `prepared` — it's the same value
+            # today, but stays correct if firmware ever adds its own
+            # normalization.
+            applied = result.current if result is not None else prepared
+        return session, info, applied
+
+    session, info, applied = _open_and_init()
+    return Dongle(
+        session,
+        info,
+        applied_config=applied,
+        keepalive=keepalive,
+        _reopener=_open_and_init,
+    )
+
+
+def connect_default() -> Dongle:
+    """Convenience wrapper for ``connect()`` with all defaults."""
+    return connect()
+
+
+def connect_mux_auto(timeout: float = DEFAULT_TIMEOUT) -> Dongle:
+    """Connect via mux only — never falls through to direct USB serial.
+
+    Sets the sticky-mux flag on success so any later :func:`connect`
+    call also stays on the mux.
+    """
+    global _used_mux
     tcp = os.environ.get("DONGLORA_MUX_TCP")
     if tcp:
         conn = _try_tcp_mux(tcp, timeout)
         if conn is not None:
-            log.debug("connected to TCP mux at %s", tcp)
-            return conn
+            _used_mux = True
+            return _session_on(conn)
 
-    # Try Unix socket mux
     sock_path = _find_mux_socket()
     if sock_path is None:
         raise FileNotFoundError("no mux socket found")
-    return mux_connect(sock_path, timeout)
+    sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+    sock.connect(sock_path)
+    _used_mux = True
+    return _session_on(MuxConnection(sock, timeout))
 
 
-def try_connect(timeout: float = DEFAULT_TIMEOUT) -> Any:
-    """Like :func:`connect` but non-blocking when no USB device is present.
+def try_connect(timeout: float = DEFAULT_TIMEOUT) -> Dongle:
+    """Like :func:`connect` but single-scan USB (no blocking wait)."""
+    global _used_mux
+    if _used_mux:
+        return connect_mux_auto(timeout)
 
-    Runs the same fallback chain (TCP mux, Unix socket mux, direct USB
-    serial) but uses a single non-blocking scan instead of polling
-    indefinitely for a USB device.  Raises if nothing is found.
-    """
-    # Try TCP mux via environment variable
     tcp = os.environ.get("DONGLORA_MUX_TCP")
     if tcp:
         conn = _try_tcp_mux(tcp, timeout)
         if conn is not None:
-            log.debug("connected to TCP mux at %s", tcp)
-            return conn
+            _used_mux = True
+            return _session_on(conn)
 
-    # Try Unix socket mux — commit if socket exists
     sock_path = _find_mux_socket()
     if sock_path is not None:
-        log.debug("mux socket found at %s — connecting via mux only", sock_path)
-        return mux_connect(sock_path, timeout)
+        sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+        sock.connect(sock_path)
+        _used_mux = True
+        return _session_on(MuxConnection(sock, timeout))
 
-    # Direct USB serial — single non-blocking scan
     port_path = find_port()
     if port_path is None:
         raise FileNotFoundError("no DongLoRa device found (no mux, no USB device)")
-    log.debug("opening serial port %s", port_path)
     ser = serial.Serial(port_path, baudrate=115200, timeout=timeout)
     ser.reset_input_buffer()
-    validate(ser)
-    return ser
+    return _session_on(ser)
+
+
+def mux_connect(path: str | None = None, timeout: float = DEFAULT_TIMEOUT) -> Dongle:
+    """Connect to the mux daemon via Unix domain socket.
+
+    Sets the sticky-mux flag on success so any later :func:`connect`
+    call also stays on the mux.
+    """
+    global _used_mux
+    if path is None:
+        path = _find_mux_socket()
+    if path is None:
+        raise FileNotFoundError("no mux socket found")
+    sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+    sock.connect(path)
+    _used_mux = True
+    return _session_on(MuxConnection(sock, timeout))
+
+
+def mux_tcp_connect(host: str, port: int, timeout: float = DEFAULT_TIMEOUT) -> Dongle:
+    """Connect to the mux daemon via TCP.
+
+    Sets the sticky-mux flag on success so any later :func:`connect`
+    call also stays on the mux.
+    """
+    global _used_mux
+    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    sock.connect((host, port))
+    _used_mux = True
+    return _session_on(MuxConnection(sock, timeout))
+
+
+def _session_on(transport: Any) -> Dongle:
+    """Bring up a :class:`Dongle` on an already-open transport."""
+    session = Session(transport)
+    try:
+        info = session.get_info()
+    except DongloraError:
+        session.close()
+        raise
+    if not isinstance(info, Info):
+        session.close()
+        raise DongloraError(f"GET_INFO returned unexpected payload: {info!r}")
+    if info.proto_major != 1:
+        session.close()
+        raise DongloraError(
+            f"device speaks DongLoRa Protocol v{info.proto_major}.{info.proto_minor}; this client requires v1.x",
+        )
+    try:
+        prepared = _prepare_config(info, LoRaConfig.default())
+        result = session.set_config(prepared)
+    except DongloraError:
+        session.close()
+        raise
+    applied = result.current if result is not None else prepared
+    return Dongle(session, info, applied_config=applied, keepalive=True)

donglora/crc.py

@@ -0,0 +1,27 @@
+"""CRC-16/CCITT-FALSE — the wire-level integrity check used by DongLoRa Protocol v2.
+
+Polynomial ``0x1021``, initial value ``0xFFFF``, no reflection,
+XOR-out ``0x0000``. Also known as CRC-16/AUTOSAR or CRC-16/IBM-3740.
+
+**Not** the same as CRC-16/KERMIT, CRC-16/XMODEM, or plain
+"CRC-16/CCITT" — those use different initial values or reflect input.
+
+Check value: ``crc16(b"123456789") == 0x29B1``. The module-level
+assertion below fails at import if the implementation drifts.
+"""
+
+from __future__ import annotations
+
+
+def crc16(data: bytes) -> int:
+    """Compute CRC-16/CCITT-FALSE over *data*. Returns a u16."""
+    crc = 0xFFFF
+    for byte in data:
+        crc ^= byte << 8
+        for _ in range(8):
+            crc = ((crc << 1) ^ 0x1021) & 0xFFFF if crc & 0x8000 else (crc << 1) & 0xFFFF
+    return crc
+
+
+# Self-check: the check value from PROTOCOL.md Appendix B.
+assert crc16(b"123456789") == 0x29B1, "CRC-16/CCITT-FALSE check value drift"

donglora/discovery.py

@@ -18,7 +18,13 @@ USB_VID: int = 0x1209
 USB_PID: int = 0x5741
 USB_VID_PID: str = "1209:5741"
 
-BRIDGE_VID_PIDS: set[str] = {"10c4:ea60", "1a86:55d4", "1a86:7523", "0403:6001"}
+BRIDGE_VID_PIDS: set[str] = {
+    "10c4:ea60",  # CP2102 (Silicon Labs)
+    "1a86:55d4",  # CH9102
+    "1a86:7522",  # CH340K — Elecrow ThinkNode-M2 ships with this
+    "1a86:7523",  # CH340
+    "0403:6001",  # FT232R (FTDI)
+}
 """Known USB-UART bridge VID:PIDs found on some board revisions."""
 
 

donglora/dongle.py

@@ -0,0 +1,364 @@
+"""The user-facing :class:`Dongle` — a connected, configured, ready-to-TX radio.
+
+Designed for "stupidly easy" ergonomics: once you have a ``Dongle`` from
+:func:`donglora.connect`, you call ``.tx(data)`` and ``.rx()`` and that's
+it. The keepalive daemon, inactivity-timeout auto-recovery, tag
+bookkeeping, CRC, COBS — all hidden.
+"""
+
+from __future__ import annotations
+
+import logging
+import threading
+from collections.abc import Callable, Iterator
+
+from donglora.errors import DongloraError, NotConfiguredError
+from donglora.events import RxEvent, TxDone
+from donglora.info import Info
+from donglora.modulation import LoRaConfig, Modulation
+from donglora.session import Session
+
+log = logging.getLogger("donglora.dongle")
+
+# Type alias for the reopener closure. Returns (new session, info,
+# applied config) — the same triple ``connect()`` produces initially.
+Reopener = Callable[[], tuple[Session, Info, "Modulation | None"]]
+
+_KEEPALIVE_INTERVAL_S: float = 0.5
+"""Default keepalive cadence. Spec §3.4 sets the inactivity timer to
+1000 ms — we ping at 500 ms for 2x margin. Hosts that send commands
+naturally won't trigger keepalive PINGs."""
+
+
+class Dongle:
+    """Live DongLoRa radio session.
+
+    Normally constructed via :func:`donglora.connect`. Users who need
+    full control can pass in a prebuilt transport + :class:`Session`,
+    but the happy path is:
+
+    .. code-block:: python
+
+        import donglora as dl
+        d = dl.connect()
+        d.tx(b"Hello")
+        for pkt in d.rx():
+            print(pkt.rssi_dbm, pkt.data)
+
+    Thread-safe: multiple threads can call ``tx`` / ``rx`` concurrently.
+    """
+
+    def __init__(
+        self,
+        session: Session,
+        info: Info,
+        *,
+        applied_config: Modulation | None,
+        keepalive: bool = True,
+        _reopener: Reopener | None = None,
+    ):
+        self._session = session
+        self._info = info
+        self._applied_config: Modulation | None = applied_config
+        self._rx_started = False
+        self._closed = False
+
+        # Reopener closure supplied by :func:`donglora.connect`. When
+        # the session's reader thread dies (e.g. mux restart, USB blip)
+        # and the caller invokes any method, the Dongle transparently
+        # calls this to build a fresh session. ``None`` disables
+        # transparent reconnect (users who constructed a Dongle
+        # manually from an existing Session keep the old behaviour).
+        self._reopener: Reopener | None = _reopener
+        # Serialises reconnect work across concurrent method calls, so
+        # multiple threads hitting a dead session only drive one
+        # reconnect attempt.
+        self._recover_lock = threading.Lock()
+
+        # Keepalive daemon: sends PING every ~500 ms unless the caller
+        # issued other traffic more recently. We track "time of last
+        # transmit" as a simple monotonic counter.
+        self._last_write_lock = threading.Lock()
+        self._last_write_time = _now()
+        self._keepalive_stop = threading.Event()
+        self._keepalive_thread: threading.Thread | None = None
+        if keepalive:
+            self._keepalive_thread = threading.Thread(
+                target=self._keepalive_loop,
+                name="donglora-keepalive",
+                daemon=True,
+            )
+            self._keepalive_thread.start()
+
+    # ── User-facing API ─────────────────────────────────────────────
+
+    @property
+    def info(self) -> Info:
+        """Cached ``GET_INFO`` snapshot from connect-time."""
+        return self._info
+
+    @property
+    def config(self) -> Modulation | None:
+        """The radio config the device actually stored on the last
+        ``SET_CONFIG`` (including any post-clamp tx_power adjustment
+        that :func:`donglora.connect` performed). ``None`` if no
+        ``SET_CONFIG`` has landed yet.
+        """
+        return self._applied_config
+
+    def tx(self, data: bytes, *, skip_cad: bool = False, timeout: float = 10.0) -> TxDone:
+        """Transmit *data*. Blocks until TX_DONE arrives.
+
+        Raises :class:`donglora.errors.ChannelBusy` if CAD detected
+        activity, :class:`donglora.errors.Cancelled` if SET_CONFIG
+        cancelled a queued TX, or other :class:`DongloraError`
+        subclasses for device errors.
+        """
+        self._check_open()
+        self._mark_write()
+        return self._with_recovery(
+            lambda: self._session.transmit(data, skip_cad=skip_cad, timeout=timeout),
+        )
+
+    def rx(self, timeout: float | None = None) -> _RxIterator:
+        """Return an iterator over incoming packets.
+
+        On first call, lazily sends ``RX_START`` to put the radio into
+        continuous receive. ``timeout`` is the per-packet deadline; set
+        to ``None`` to block forever (the common case for listening
+        scripts).
+        """
+        self._check_open()
+        if not self._rx_started:
+            self._mark_write()
+            self._with_recovery(lambda: self._session.rx_start())
+            self._rx_started = True
+        return _RxIterator(self, timeout)
+
+    def recv(self, timeout: float | None = None) -> RxEvent | None:
+        """Block on a single RX event. Convenience for ``next(iter(d.rx(timeout)))``.
+
+        Returns ``None`` on timeout. Lazily starts continuous RX on
+        first call. If the session dies (mux restart, transport blip)
+        while waiting, transparently reconnects and returns ``None`` —
+        the caller just loops and calls ``recv()`` again.
+        """
+        self._check_open()
+        self._ensure_session_alive()
+        if not self._rx_started:
+            self._mark_write()
+            self._with_recovery(lambda: self._session.rx_start())
+            self._rx_started = True
+        pkt = self._session.next_rx(timeout)
+        if pkt is None and not self._session.is_alive:
+            # Session died during the wait (reader posted the dead
+            # sentinel which next_rx filtered to None). Reconnect now
+            # so the *next* recv() sees a live session.
+            self._ensure_session_alive()
+        return pkt
+
+    def rx_stop(self) -> None:
+        """Stop continuous RX. Rare; most programs just close the dongle."""
+        self._check_open()
+        self._ensure_session_alive()
+        self._mark_write()
+        self._session.rx_stop()
+        self._rx_started = False
+
+    def set_config(self, config: Modulation) -> None:
+        """Apply a new radio configuration. Blocks on the ``OK`` response."""
+        self._check_open()
+        self._ensure_session_alive()
+        self._mark_write()
+        self._session.set_config(config)
+        self._applied_config = config
+        # SET_CONFIG aborts any continuous RX on the device side.
+        self._rx_started = False
+
+    def ping(self) -> None:
+        """Send a PING. Rarely needed directly — the keepalive daemon
+        handles session-liveness automatically.
+        """
+        self._check_open()
+        self._ensure_session_alive()
+        self._mark_write()
+        self._session.ping()
+
+    def close(self) -> None:
+        """Close the session. Idempotent."""
+        if self._closed:
+            return
+        self._closed = True
+        self._keepalive_stop.set()
+        self._session.close()
+
+    # Context manager
+    def __enter__(self) -> Dongle:
+        return self
+
+    def __exit__(self, *exc: object) -> None:
+        self.close()
+
+    # ── Internals ───────────────────────────────────────────────────
+
+    def _check_open(self) -> None:
+        if self._closed:
+            raise DongloraError("dongle is closed")
+
+    def _mark_write(self) -> None:
+        with self._last_write_lock:
+            self._last_write_time = _now()
+
+    def _ensure_session_alive(self) -> None:
+        """If the session's reader thread has died, rebuild the session.
+
+        Blocks until reconnect succeeds or the Dongle is closed.
+        No-op when the session is healthy. Safe to call concurrently —
+        only one thread drives the actual reconnect, the rest wait on
+        the shared lock.
+        """
+        if self._session.is_alive:
+            return
+        if self._reopener is None:
+            # Manually-constructed Dongle without a reopener — surface
+            # the death as an error rather than silently swallowing it.
+            raise DongloraError("session closed; no reopener configured")
+        with self._recover_lock:
+            # Another thread may have already reconnected by the time
+            # we got the lock.
+            if self._session.is_alive:
+                return
+            self._recover_session_locked()
+
+    def _recover_session_locked(self) -> None:
+        """Replace ``self._session`` with a fresh one.
+
+        Called under ``_recover_lock``. Retries the reopener with a
+        backoff until success or the Dongle is closed. Re-applies the
+        cached config (if any) and restarts RX (if it was running)
+        before returning, so the caller's next command sees a live
+        dongle in the same logical state.
+        """
+        assert self._reopener is not None
+        log.warning("dongle: session died, reconnecting transparently")
+        old_session = self._session
+        import contextlib as _contextlib
+
+        with _contextlib.suppress(Exception):
+            old_session.close()
+
+        backoff = 0.5
+        max_backoff = 2.0
+        while not self._closed and not self._keepalive_stop.is_set():
+            try:
+                new_session, new_info, applied = self._reopener()
+            except (DongloraError, OSError) as exc:
+                log.info("dongle: reconnect attempt failed (%s); retrying...", exc)
+                if self._keepalive_stop.wait(backoff):
+                    return  # close() fired during backoff
+                backoff = min(backoff * 1.5, max_backoff)
+                continue
+
+            self._session = new_session
+            self._info = new_info
+            if applied is not None:
+                self._applied_config = applied
+            # Restart RX if the caller had it running.
+            if self._rx_started:
+                try:
+                    new_session.rx_start()
+                except DongloraError as exc:
+                    log.info("dongle: restart rx after reconnect failed: %s", exc)
+                    self._rx_started = False
+            log.info("dongle: reconnect successful")
+            return
+
+    def _with_recovery(self, op):
+        """Run *op*, transparently recovering from two kinds of drop:
+
+        * Session reader death (mux restart, transport blip) —
+          rebuild the session via :meth:`_ensure_session_alive` and
+          retry once.
+        * ``ERR(ENOTCONFIGURED)`` from an inactivity timeout —
+          re-apply the cached config and retry once.
+
+        Other errors pass through untouched.
+        """
+        self._ensure_session_alive()
+        try:
+            return op()
+        except NotConfiguredError:
+            if self._applied_config is None:
+                raise
+            log.info("dongle: auto-recovering after inactivity timeout")
+            self._session.set_config(self._applied_config)
+            return op()
+        except DongloraError:
+            # If the session died mid-call, reconnect and retry once.
+            if not self._session.is_alive and self._reopener is not None:
+                self._ensure_session_alive()
+                return op()
+            raise
+
+    def _keepalive_loop(self) -> None:
+        while not self._keepalive_stop.wait(_KEEPALIVE_INTERVAL_S):
+            # If the session died, let the keepalive thread drive the
+            # reconnect proactively — without this, we'd only notice
+            # when the caller next invoked a public method.
+            if not self._session.is_alive and self._reopener is not None:
+                try:
+                    self._ensure_session_alive()
+                except DongloraError as exc:
+                    log.debug("keepalive reconnect failed: %s", exc)
+                continue
+            with self._last_write_lock:
+                since = _now() - self._last_write_time
+            if since < _KEEPALIVE_INTERVAL_S:
+                continue
+            try:
+                self._session.ping(timeout=2.0)
+                with self._last_write_lock:
+                    self._last_write_time = _now()
+            except NotConfiguredError:
+                # Session timed out during quiet period. Try to re-apply
+                # the cached config so the next user call sees a live
+                # session. If the caller issues a command first, the
+                # with_recovery path will handle it instead — so treat
+                # failures here as best-effort.
+                if self._applied_config is not None:
+                    try:
+                        self._session.set_config(self._applied_config)
+                    except Exception as exc:
+                        log.debug("keepalive recovery failed: %s", exc)
+            except DongloraError as exc:
+                log.debug("keepalive ping failed: %s", exc)
+            except Exception as exc:
+                log.debug("keepalive thread quiet error: %s", exc)
+
+
+class _RxIterator:
+    """Iterator view over a Dongle's incoming RX events."""
+
+    def __init__(self, dongle: Dongle, timeout: float | None):
+        self._dongle = dongle
+        self._timeout = timeout
+
+    def __iter__(self) -> Iterator[RxEvent]:
+        return self
+
+    def __next__(self) -> RxEvent:
+        pkt = self._dongle._session.next_rx(self._timeout)
+        if pkt is None:
+            raise StopIteration
+        return pkt
+
+
+def _now() -> float:
+    import time
+
+    return time.monotonic()
+
+
+# Re-export the default LoRa config builder so users don't have to
+# import from modulation.py.
+__all__ = ["Dongle", "LoRaConfig"]

donglora/errors.py

@@ -0,0 +1,142 @@
+"""Wire error codes + Python exception hierarchy.
+
+``ErrorCode`` mirrors PROTOCOL.md §7. ``DongloraError`` subclasses are
+raised by the high-level :class:`donglora.dongle.Dongle` so callers can
+catch specific failures (e.g. ``ChannelBusy``) without inspecting codes.
+"""
+
+from __future__ import annotations
+
+import enum
+
+
+class ErrorCode(enum.IntEnum):
+    """Wire-level error code (u16 LE). Values assigned by PROTOCOL.md §7."""
+
+    # Synchronous (0x0001..=0x00FF)
+    EPARAM = 0x0001
+    ELENGTH = 0x0002
+    ENOT_CONFIGURED = 0x0003
+    EMODULATION = 0x0004
+    EUNKNOWN_CMD = 0x0005
+    EBUSY = 0x0006
+
+    # Asynchronous (0x0100..=0x01FF)
+    ERADIO = 0x0101
+    EFRAME = 0x0102
+    EINTERNAL = 0x0103
+
+    @classmethod
+    def from_u16(cls, raw: int) -> ErrorCode | int:
+        """Return the named variant if recognised, otherwise the raw int."""
+        try:
+            return cls(raw)
+        except ValueError:
+            return raw
+
+
+# ── Python exception hierarchy ─────────────────────────────────────
+
+
+class DongloraError(Exception):
+    """Base class for all DongLoRa client errors."""
+
+
+class ConfigNotSupported(DongloraError):
+    """The requested config contains a field the device cannot satisfy.
+
+    Raised client-side, before ``SET_CONFIG`` hits the wire, for fields
+    that are *not* safe to silently auto-adjust:
+
+    * ``freq_hz`` outside the device's reported
+      ``freq_min_hz..freq_max_hz`` — silently shifting 915 MHz to
+      868 MHz (or vice versa) crosses regulatory boundaries.
+    * ``sf`` not in ``supported_sf_bitmap`` — changes airtime and
+      sensitivity in ways the caller needs to know about.
+    * ``bw`` not in ``supported_bw_bitmap`` — same as SF.
+
+    ``tx_power_dbm`` is *not* in this list: it's clamped transparently
+    because "give me max power" returning less than requested is the
+    universally expected behavior.
+    """
+
+
+class FrameError(DongloraError):
+    """COBS decode, CRC check, or length check failed on an inbound frame."""
+
+
+class TimeoutError_(DongloraError):
+    """Command response not received within the configured deadline."""
+
+
+class DeviceError(DongloraError):
+    """The device returned an ``ERR`` frame."""
+
+    def __init__(self, code: ErrorCode | int, *, tag: int | None = None):
+        self.code = code
+        self.tag = tag
+        name = code.name if isinstance(code, ErrorCode) else f"0x{int(code):04X}"
+        super().__init__(f"device error {name} (tag={tag})")
+
+
+class NotConfiguredError(DeviceError):
+    """Mapped from ``ERR(ENOTCONFIGURED)``."""
+
+
+class BusyError(DeviceError):
+    """Mapped from ``ERR(EBUSY)``."""
+
+
+class ParamError(DeviceError):
+    """Mapped from ``ERR(EPARAM)``."""
+
+
+class LengthError(DeviceError):
+    """Mapped from ``ERR(ELENGTH)``."""
+
+
+class ModulationError(DeviceError):
+    """Mapped from ``ERR(EMODULATION)``."""
+
+
+class UnknownCommandError(DeviceError):
+    """Mapped from ``ERR(EUNKNOWN_CMD)``."""
+
+
+class RadioError(DeviceError):
+    """Mapped from ``ERR(ERADIO)`` — SPI error or unexpected hardware state."""
+
+
+class InternalError(DeviceError):
+    """Mapped from ``ERR(EINTERNAL)`` — firmware bug or invariant violation."""
+
+
+_SPECIALISATIONS: dict[int, type[DeviceError]] = {
+    ErrorCode.EPARAM: ParamError,
+    ErrorCode.ELENGTH: LengthError,
+    ErrorCode.ENOT_CONFIGURED: NotConfiguredError,
+    ErrorCode.EMODULATION: ModulationError,
+    ErrorCode.EUNKNOWN_CMD: UnknownCommandError,
+    ErrorCode.EBUSY: BusyError,
+    ErrorCode.ERADIO: RadioError,
+    ErrorCode.EINTERNAL: InternalError,
+}
+
+
+def device_error(code: ErrorCode | int, *, tag: int | None = None) -> DeviceError:
+    """Construct the most specific :class:`DeviceError` subclass for *code*."""
+    cls = _SPECIALISATIONS.get(int(code), DeviceError)
+    return cls(code, tag=tag)
+
+
+# ── TX-specific non-error results ──────────────────────────────────
+
+
+class ChannelBusy(DongloraError):
+    """CAD detected activity and TX was not attempted. Retry with new tag."""
+
+
+class Cancelled(DongloraError):
+    """A queued TX was cancelled before it reached the air (SET_CONFIG
+    or disconnect interrupted the queue).
+    """

donglora/events.py

@@ -0,0 +1,186 @@
+"""Device-to-host message payloads: ``OK`` / ``ERR`` / ``RX`` / ``TX_DONE``."""
+
+from __future__ import annotations
+
+import enum
+import struct
+from dataclasses import dataclass
+
+from donglora.errors import ErrorCode
+from donglora.info import Info
+from donglora.modulation import Modulation, decode_modulation, encode_modulation
+
+# Message type identifiers
+TYPE_OK: int = 0x80
+TYPE_ERR: int = 0x81
+TYPE_RX: int = 0xC0
+TYPE_TX_DONE: int = 0xC1
+
+
+# ── SET_CONFIG response payload ────────────────────────────────────
+
+
+class SetConfigResultCode(enum.IntEnum):
+    APPLIED = 0
+    ALREADY_MATCHED = 1
+    LOCKED_MISMATCH = 2
+
+
+class Owner(enum.IntEnum):
+    NONE = 0
+    MINE = 1
+    OTHER = 2
+
+
+@dataclass(frozen=True)
+class SetConfigResult:
+    result: SetConfigResultCode
+    owner: Owner
+    current: Modulation
+
+    def encode(self) -> bytes:
+        return bytes([int(self.result), int(self.owner)]) + encode_modulation(self.current)
+
+    @classmethod
+    def decode(cls, data: bytes) -> SetConfigResult:
+        if len(data) < 2:
+            raise ValueError("SetConfigResult too short")
+        return cls(
+            result=SetConfigResultCode(data[0]),
+            owner=Owner(data[1]),
+            current=decode_modulation(data[2:]),
+        )
+
+
+# ── TX_DONE payload ────────────────────────────────────────────────
+
+
+class TxResult(enum.IntEnum):
+    TRANSMITTED = 0
+    CHANNEL_BUSY = 1
+    CANCELLED = 2
+
+
+@dataclass(frozen=True)
+class TxDone:
+    result: TxResult
+    airtime_us: int
+
+    def encode(self) -> bytes:
+        return bytes([int(self.result)]) + struct.pack("<I", self.airtime_us)
+
+    @classmethod
+    def decode(cls, data: bytes) -> TxDone:
+        if len(data) != 5:
+            raise ValueError(f"TxDone wire size must be 5, got {len(data)}")
+        result = TxResult(data[0])
+        (airtime_us,) = struct.unpack_from("<I", data, 1)
+        return cls(result=result, airtime_us=airtime_us)
+
+
+# ── RX event payload ───────────────────────────────────────────────
+
+
+class RxOrigin(enum.IntEnum):
+    OTA = 0
+    LOCAL_LOOPBACK = 1
+
+
+@dataclass(frozen=True)
+class RxEvent:
+    """Rich over-the-air packet metadata + the received bytes.
+
+    ``rssi_dbm`` and ``snr_db`` are exposed as floats (converted from
+    the wire's tenths-of-dB representation) so user code reads like
+    ``pkt.rssi_dbm`` instead of having to divide by 10.
+    """
+
+    rssi_dbm: float
+    snr_db: float
+    freq_err_hz: int
+    timestamp_us: int
+    crc_valid: bool
+    packets_dropped: int
+    origin: RxOrigin
+    data: bytes
+
+    METADATA_SIZE: int = 20
+
+    def encode(self) -> bytes:
+        return (
+            struct.pack("<h", round(self.rssi_dbm * 10))
+            + struct.pack("<h", round(self.snr_db * 10))
+            + struct.pack("<i", self.freq_err_hz)
+            + struct.pack("<Q", self.timestamp_us)
+            + bytes([1 if self.crc_valid else 0])
+            + struct.pack("<H", self.packets_dropped)
+            + bytes([int(self.origin)])
+            + self.data
+        )
+
+    @classmethod
+    def decode(cls, data: bytes) -> RxEvent:
+        if len(data) < cls.METADATA_SIZE:
+            raise ValueError(f"RxEvent payload too short: {len(data)}")
+        (rssi_raw,) = struct.unpack_from("<h", data, 0)
+        (snr_raw,) = struct.unpack_from("<h", data, 2)
+        (freq_err_hz,) = struct.unpack_from("<i", data, 4)
+        (timestamp_us,) = struct.unpack_from("<Q", data, 8)
+        if data[16] not in (0, 1):
+            raise ValueError("crc_valid must be 0 or 1")
+        (packets_dropped,) = struct.unpack_from("<H", data, 17)
+        origin = RxOrigin(data[19])
+        return cls(
+            rssi_dbm=rssi_raw / 10.0,
+            snr_db=snr_raw / 10.0,
+            freq_err_hz=freq_err_hz,
+            timestamp_us=timestamp_us,
+            crc_valid=bool(data[16]),
+            packets_dropped=packets_dropped,
+            origin=origin,
+            data=bytes(data[cls.METADATA_SIZE :]),
+        )
+
+
+# ── OK payload helpers (context-dependent shape) ──────────────────
+
+# Import command type IDs lazily inside functions to avoid cycles.
+
+
+def parse_ok_payload(originating_cmd_type: int, payload: bytes):
+    """Parse the payload of an ``OK`` frame given the type of the
+    originating H→D command. Returns:
+
+    - ``None`` for ``PING`` / ``TX`` / ``RX_START`` / ``RX_STOP`` (empty payload)
+    - an :class:`Info` for ``GET_INFO``
+    - a :class:`SetConfigResult` for ``SET_CONFIG``
+    """
+    from donglora.commands import (
+        TYPE_GET_INFO,
+        TYPE_PING,
+        TYPE_RX_START,
+        TYPE_RX_STOP,
+        TYPE_SET_CONFIG,
+        TYPE_TX,
+    )
+
+    if originating_cmd_type in (TYPE_PING, TYPE_TX, TYPE_RX_START, TYPE_RX_STOP):
+        if payload:
+            raise ValueError(f"expected empty OK payload for cmd 0x{originating_cmd_type:02X}")
+        return None
+    if originating_cmd_type == TYPE_GET_INFO:
+        return Info.decode(payload)
+    if originating_cmd_type == TYPE_SET_CONFIG:
+        return SetConfigResult.decode(payload)
+    raise ValueError(f"no OK shape for originating cmd 0x{originating_cmd_type:02X}")
+
+
+def encode_err_payload(code: ErrorCode | int) -> bytes:
+    return struct.pack("<H", int(code))
+
+
+def decode_err_payload(data: bytes) -> ErrorCode | int:
+    if len(data) != 2:
+        raise ValueError(f"ERR payload must be 2 bytes, got {len(data)}")
+    (raw,) = struct.unpack_from("<H", data, 0)
+    return ErrorCode.from_u16(raw)

donglora/frame.py

@@ -0,0 +1,150 @@
+"""DongLoRa Protocol frame encode/decode: ``COBS(type || tag_le || payload || crc_le) || 0x00``.
+
+This module owns the wire-level codec. Nothing protocol-semantic lives
+here; higher-level modules parse the ``(type_id, tag, payload)`` tuple
+into typed commands / events.
+"""
+
+from __future__ import annotations
+
+import struct
+from collections.abc import Iterator
+from dataclasses import dataclass
+from typing import Protocol, runtime_checkable
+
+from cobs import cobs
+
+from donglora.crc import crc16
+
+# ── Size constants (kept in lockstep with the Rust crate) ───────────
+
+MAX_OTA_PAYLOAD: int = 255
+"""Maximum over-the-air LoRa packet payload. Chip-dependent per
+PROTOCOL.md §6.2; 255 is the ceiling for all currently-supported
+Semtech silicon."""
+
+MAX_PAYLOAD_FIELD: int = MAX_OTA_PAYLOAD + 20
+"""Maximum DongLoRa Protocol frame payload-field size. The ``+20`` accounts for the
+RX event's fixed metadata prefix."""
+
+FRAME_HEADER_SIZE: int = 3  # type(1) + tag(2)
+FRAME_TRAILER_SIZE: int = 2  # crc16(2)
+MAX_PRE_COBS_FRAME: int = FRAME_HEADER_SIZE + MAX_PAYLOAD_FIELD + FRAME_TRAILER_SIZE
+MAX_COBS_OVERHEAD: int = 3  # ceil(280 / 254) + 1
+MAX_WIRE_FRAME: int = MAX_PRE_COBS_FRAME + MAX_COBS_OVERHEAD + 1
+
+
+# ── Frame encoding ─────────────────────────────────────────────────
+
+
+class FrameTooLargeError(ValueError):
+    """Payload exceeds ``MAX_PAYLOAD_FIELD``."""
+
+
+def encode_frame(type_id: int, tag: int, payload: bytes) -> bytes:
+    """Encode a complete wire-ready DongLoRa Protocol frame.
+
+    Returns ``COBS(type || tag_le || payload || crc_le) || 0x00``.
+    """
+    if not (0 <= type_id <= 0xFF):
+        raise ValueError(f"type_id out of range: {type_id}")
+    if not (0 <= tag <= 0xFFFF):
+        raise ValueError(f"tag out of range: {tag}")
+    if len(payload) > MAX_PAYLOAD_FIELD:
+        raise FrameTooLargeError(f"payload too large ({len(payload)} > {MAX_PAYLOAD_FIELD})")
+    body = struct.pack("<BH", type_id, tag) + payload
+    crc = crc16(body)
+    pre_cobs = body + struct.pack("<H", crc)
+    return cobs.encode(pre_cobs) + b"\x00"
+
+
+# ── Decoded-frame result ───────────────────────────────────────────
+
+
+@dataclass(frozen=True)
+class Frame:
+    """A successfully-decoded DongLoRa Protocol frame."""
+
+    type_id: int
+    tag: int
+    payload: bytes
+
+
+class FrameError(Exception):
+    """A frame failed COBS, CRC, or minimum-length validation."""
+
+
+class FrameCrcError(FrameError):
+    """CRC trailer didn't match the computed CRC over ``type || tag || payload``."""
+
+
+class FrameCobsError(FrameError):
+    """COBS decode failed on the bytes before the ``0x00`` delimiter."""
+
+
+class FrameTooShortError(FrameError):
+    """Decoded frame was smaller than the 5-byte minimum."""
+
+
+def decode_frame(frame_bytes: bytes) -> Frame:
+    """Decode a single COBS+sentinel-terminated DongLoRa Protocol frame.
+
+    *frame_bytes* must NOT include the trailing ``0x00``.
+    """
+    try:
+        decoded = cobs.decode(frame_bytes)
+    except cobs.DecodeError as exc:
+        raise FrameCobsError(str(exc)) from exc
+    if len(decoded) < FRAME_HEADER_SIZE + FRAME_TRAILER_SIZE:
+        raise FrameTooShortError(f"decoded frame too short: {len(decoded)} bytes")
+    body, crc_bytes = decoded[:-FRAME_TRAILER_SIZE], decoded[-FRAME_TRAILER_SIZE:]
+    expected = crc16(body)
+    (got,) = struct.unpack("<H", crc_bytes)
+    if expected != got:
+        raise FrameCrcError(f"CRC mismatch: got 0x{got:04X}, expected 0x{expected:04X}")
+    type_id = body[0]
+    (tag,) = struct.unpack_from("<H", body, 1)
+    payload = body[FRAME_HEADER_SIZE:]
+    return Frame(type_id=type_id, tag=tag, payload=payload)
+
+
+# ── Streaming reader ───────────────────────────────────────────────
+
+
+@runtime_checkable
+class Readable(Protocol):
+    """Anything with a blocking ``read(n)`` method — serial port, socket, etc."""
+
+    def read(self, n: int = 1) -> bytes: ...
+
+
+def read_frame(reader: Readable) -> Frame | None:
+    """Block on *reader* until a full COBS-delimited frame arrives.
+
+    Returns the decoded :class:`Frame`, or ``None`` on transport timeout.
+    Raises :class:`FrameError` on CRC/COBS/length failure so the caller
+    can distinguish corruption from timeout.
+    """
+    buf = bytearray()
+    while True:
+        b = reader.read(1)
+        if not b:
+            return None
+        if b == b"\x00":
+            if not buf:
+                return None
+            return decode_frame(bytes(buf))
+        buf.extend(b)
+
+
+def iter_frames(data: bytes) -> Iterator[Frame]:
+    """Yield each complete frame embedded in *data* (for tests / replay).
+
+    Raises :class:`FrameError` on the first corrupt frame encountered.
+    """
+    start = 0
+    for i, byte in enumerate(data):
+        if byte == 0x00:
+            if i > start:
+                yield decode_frame(bytes(data[start:i]))
+            start = i + 1

donglora/info.py

@@ -0,0 +1,196 @@
+"""``GET_INFO`` response payload + capability bitmap constants."""
+
+from __future__ import annotations
+
+import enum
+import struct
+from dataclasses import dataclass, field
+
+MAX_MCU_UID_LEN: int = 32
+MAX_RADIO_UID_LEN: int = 16
+
+
+# ── Capability bits (PROTOCOL.md §9) ──────────────────────────────
+
+
+class Capability:
+    """Bit masks for ``Info.capability_bitmap``.
+
+    Use like: ``if info.supports(Capability.LORA | Capability.CAD_BEFORE_TX): ...``.
+    """
+
+    # Modulations
+    LORA = 1 << 0
+    FSK = 1 << 1
+    GFSK = 1 << 2
+    LR_FHSS = 1 << 3
+    FLRC = 1 << 4
+    MSK = 1 << 5
+    GMSK = 1 << 6
+    BLE_COMPATIBLE = 1 << 7
+
+    # Radio features
+    CAD_BEFORE_TX = 1 << 16
+    IQ_INVERSION = 1 << 17
+    RANGING = 1 << 18
+    GNSS_SCAN = 1 << 19
+    WIFI_MAC_SCAN = 1 << 20
+    SPECTRAL_SCAN = 1 << 21
+    FULL_DUPLEX = 1 << 22
+
+    # Protocol features
+    MULTI_CLIENT = 1 << 32
+
+
+# ── Radio chip IDs (PROTOCOL.md §8) ───────────────────────────────
+
+
+class RadioChipId(enum.IntEnum):
+    UNKNOWN = 0x0000
+    SX1261 = 0x0001
+    SX1262 = 0x0002
+    SX1268 = 0x0003
+    LLCC68 = 0x0004
+    SX1272 = 0x0010
+    SX1276 = 0x0011
+    SX1277 = 0x0012
+    SX1278 = 0x0013
+    SX1279 = 0x0014
+    SX1280 = 0x0020
+    SX1281 = 0x0021
+    LR1110 = 0x0030
+    LR1120 = 0x0031
+    LR1121 = 0x0032
+    LR2021 = 0x0040
+
+
+# ── Info struct ───────────────────────────────────────────────────
+
+
+@dataclass(frozen=True)
+class Info:
+    """``GET_INFO`` response payload. Stable for the lifetime of a session."""
+
+    proto_major: int
+    proto_minor: int
+    fw_major: int
+    fw_minor: int
+    fw_patch: int
+    radio_chip_id: int
+    capability_bitmap: int
+    supported_sf_bitmap: int
+    supported_bw_bitmap: int
+    max_payload_bytes: int
+    rx_queue_capacity: int
+    tx_queue_capacity: int
+    freq_min_hz: int
+    freq_max_hz: int
+    tx_power_min_dbm: int
+    tx_power_max_dbm: int
+    mcu_uid: bytes
+    radio_uid: bytes
+
+    MIN_WIRE_SIZE: int = field(default=37, init=False, repr=False, compare=False)
+
+    @property
+    def chip(self) -> RadioChipId | int:
+        """Project ``radio_chip_id`` into the :class:`RadioChipId` enum if
+        recognised; otherwise return the raw u16 so nothing is lost for
+        forward-compat with future chips.
+        """
+        try:
+            return RadioChipId(self.radio_chip_id)
+        except ValueError:
+            return self.radio_chip_id
+
+    def supports(self, mask: int) -> bool:
+        """Return True if all bits in *mask* are set in the capability bitmap."""
+        return (self.capability_bitmap & mask) == mask
+
+    def supported_sf(self) -> list[int]:
+        """List of spreading factors (5..12) the device supports."""
+        return [sf for sf in range(16) if self.supported_sf_bitmap & (1 << sf)]
+
+    def encode(self) -> bytes:
+        if len(self.mcu_uid) > MAX_MCU_UID_LEN:
+            raise ValueError(f"mcu_uid too long: {len(self.mcu_uid)}")
+        if len(self.radio_uid) > MAX_RADIO_UID_LEN:
+            raise ValueError(f"radio_uid too long: {len(self.radio_uid)}")
+        header = struct.pack(
+            "<BBBBBHQHHHHHIIbbB",
+            self.proto_major,
+            self.proto_minor,
+            self.fw_major,
+            self.fw_minor,
+            self.fw_patch,
+            self.radio_chip_id,
+            self.capability_bitmap,
+            self.supported_sf_bitmap,
+            self.supported_bw_bitmap,
+            self.max_payload_bytes,
+            self.rx_queue_capacity,
+            self.tx_queue_capacity,
+            self.freq_min_hz,
+            self.freq_max_hz,
+            self.tx_power_min_dbm,
+            self.tx_power_max_dbm,
+            len(self.mcu_uid),
+        )
+        return header + self.mcu_uid + bytes([len(self.radio_uid)]) + self.radio_uid
+
+    @classmethod
+    def decode(cls, data: bytes) -> Info:
+        if len(data) < 37:
+            raise ValueError(f"Info payload too short: {len(data)}")
+        (
+            proto_major,
+            proto_minor,
+            fw_major,
+            fw_minor,
+            fw_patch,
+            radio_chip_id,
+            capability_bitmap,
+            supported_sf_bitmap,
+            supported_bw_bitmap,
+            max_payload_bytes,
+            rx_queue_capacity,
+            tx_queue_capacity,
+            freq_min_hz,
+            freq_max_hz,
+            tx_power_min_dbm,
+            tx_power_max_dbm,
+            mcu_uid_len,
+        ) = struct.unpack_from("<BBBBBHQHHHHHIIbbB", data, 0)
+        if mcu_uid_len > MAX_MCU_UID_LEN:
+            raise ValueError(f"mcu_uid_len out of range: {mcu_uid_len}")
+        if len(data) < 36 + mcu_uid_len + 1:
+            raise ValueError(f"Info payload truncated after mcu_uid: {len(data)}")
+        mcu_uid = bytes(data[36 : 36 + mcu_uid_len])
+        radio_len_idx = 36 + mcu_uid_len
+        radio_uid_len = data[radio_len_idx]
+        if radio_uid_len > MAX_RADIO_UID_LEN:
+            raise ValueError(f"radio_uid_len out of range: {radio_uid_len}")
+        radio_start = radio_len_idx + 1
+        if len(data) < radio_start + radio_uid_len:
+            raise ValueError(f"Info payload truncated after radio_uid: {len(data)}")
+        radio_uid = bytes(data[radio_start : radio_start + radio_uid_len])
+        return cls(
+            proto_major=proto_major,
+            proto_minor=proto_minor,
+            fw_major=fw_major,
+            fw_minor=fw_minor,
+            fw_patch=fw_patch,
+            radio_chip_id=radio_chip_id,
+            capability_bitmap=capability_bitmap,
+            supported_sf_bitmap=supported_sf_bitmap,
+            supported_bw_bitmap=supported_bw_bitmap,
+            max_payload_bytes=max_payload_bytes,
+            rx_queue_capacity=rx_queue_capacity,
+            tx_queue_capacity=tx_queue_capacity,
+            freq_min_hz=freq_min_hz,
+            freq_max_hz=freq_max_hz,
+            tx_power_min_dbm=tx_power_min_dbm,
+            tx_power_max_dbm=tx_power_max_dbm,
+            mcu_uid=mcu_uid,
+            radio_uid=radio_uid,
+        )

donglora/modulation.py

@@ -0,0 +1,406 @@
+"""Per-modulation config dataclasses for ``SET_CONFIG`` payloads.
+
+Mirrors the Rust crate's ``modulation`` module byte-for-byte. Users
+build a :class:`LoRaConfig` (or FSK/LR-FHSS/FLRC variant) and pass it
+to :meth:`donglora.dongle.Dongle.set_config` or to :func:`connect` as
+an override.
+
+The `.default()` classmethod on each returns a sensible starting point
+— for LoRa that's the Appendix C.2.3 canonical EU868 config, which is
+also what :func:`connect()` auto-applies.
+"""
+
+from __future__ import annotations
+
+import enum
+import struct
+from dataclasses import dataclass, field
+
+# ── Modulation ID (u8 prefix byte on every SET_CONFIG payload) ────
+
+
+class ModulationId(enum.IntEnum):
+    LORA = 0x01
+    FSK_GFSK = 0x02
+    LR_FHSS = 0x03
+    FLRC = 0x04
+
+
+# ── LoRa enums ─────────────────────────────────────────────────────
+
+
+class LoRaBandwidth(enum.IntEnum):
+    """LoRa bandwidth enum — integer is the wire value, not kHz."""
+
+    KHZ_7_81 = 0
+    KHZ_10_42 = 1
+    KHZ_15_63 = 2
+    KHZ_20_83 = 3
+    KHZ_31_25 = 4
+    KHZ_41_67 = 5
+    KHZ_62_5 = 6
+    KHZ_125 = 7
+    KHZ_250 = 8
+    KHZ_500 = 9
+    KHZ_200 = 10  # SX128x
+    KHZ_400 = 11  # SX128x
+    KHZ_800 = 12  # SX128x
+    KHZ_1600 = 13  # SX128x
+
+    @property
+    def khz(self) -> float:
+        """Nominal bandwidth in kHz. Use with ``:g`` or ``:.1f`` for display."""
+        return _BW_KHZ[self]
+
+
+_BW_KHZ: dict[LoRaBandwidth, float] = {
+    LoRaBandwidth.KHZ_7_81: 7.81,
+    LoRaBandwidth.KHZ_10_42: 10.42,
+    LoRaBandwidth.KHZ_15_63: 15.63,
+    LoRaBandwidth.KHZ_20_83: 20.83,
+    LoRaBandwidth.KHZ_31_25: 31.25,
+    LoRaBandwidth.KHZ_41_67: 41.67,
+    LoRaBandwidth.KHZ_62_5: 62.5,
+    LoRaBandwidth.KHZ_125: 125.0,
+    LoRaBandwidth.KHZ_250: 250.0,
+    LoRaBandwidth.KHZ_500: 500.0,
+    LoRaBandwidth.KHZ_200: 200.0,
+    LoRaBandwidth.KHZ_400: 400.0,
+    LoRaBandwidth.KHZ_800: 800.0,
+    LoRaBandwidth.KHZ_1600: 1600.0,
+}
+
+
+class LoRaCodingRate(enum.IntEnum):
+    CR_4_5 = 0
+    CR_4_6 = 1
+    CR_4_7 = 2
+    CR_4_8 = 3
+
+
+class LoRaHeaderMode(enum.IntEnum):
+    EXPLICIT = 0
+    IMPLICIT = 1
+
+
+# ── LoRa config ────────────────────────────────────────────────────
+
+
+@dataclass(frozen=True)
+class LoRaConfig:
+    """LoRa modulation parameters. 15-byte wire struct."""
+
+    freq_hz: int
+    sf: int  # 5-12
+    bw: LoRaBandwidth
+    cr: LoRaCodingRate
+    preamble_len: int = 8
+    sync_word: int = 0x1424
+    tx_power_dbm: int = 14
+    header_mode: LoRaHeaderMode = LoRaHeaderMode.EXPLICIT
+    payload_crc: bool = True
+    iq_invert: bool = False
+
+    WIRE_SIZE: int = field(default=15, init=False, repr=False, compare=False)
+
+    @classmethod
+    def default(cls) -> LoRaConfig:
+        """PROTOCOL.md §C.2.3 canonical EU868 config — also what
+        :func:`donglora.connect` auto-applies.
+        """
+        return cls(
+            freq_hz=868_100_000,
+            sf=7,
+            bw=LoRaBandwidth.KHZ_125,
+            cr=LoRaCodingRate.CR_4_5,
+            preamble_len=8,
+            sync_word=0x1424,
+            tx_power_dbm=14,
+            header_mode=LoRaHeaderMode.EXPLICIT,
+            payload_crc=True,
+            iq_invert=False,
+        )
+
+    def encode(self) -> bytes:
+        return (
+            struct.pack("<I", self.freq_hz)
+            + bytes([self.sf, int(self.bw), int(self.cr)])
+            + struct.pack("<H", self.preamble_len)
+            + struct.pack("<H", self.sync_word)
+            + struct.pack("<b", self.tx_power_dbm)
+            + bytes(
+                [
+                    int(self.header_mode),
+                    1 if self.payload_crc else 0,
+                    1 if self.iq_invert else 0,
+                ],
+            )
+        )
+
+    @classmethod
+    def decode(cls, data: bytes) -> LoRaConfig:
+        if len(data) != 15:
+            raise ValueError(f"LoRaConfig wire size must be 15 bytes, got {len(data)}")
+        (freq_hz,) = struct.unpack_from("<I", data, 0)
+        sf = data[4]
+        bw = LoRaBandwidth(data[5])
+        cr = LoRaCodingRate(data[6])
+        (preamble_len,) = struct.unpack_from("<H", data, 7)
+        (sync_word,) = struct.unpack_from("<H", data, 9)
+        (tx_power_dbm,) = struct.unpack_from("<b", data, 11)
+        header_mode = LoRaHeaderMode(data[12])
+        if data[13] not in (0, 1) or data[14] not in (0, 1):
+            raise ValueError("LoRaConfig payload_crc / iq_invert must be 0 or 1")
+        return cls(
+            freq_hz=freq_hz,
+            sf=sf,
+            bw=bw,
+            cr=cr,
+            preamble_len=preamble_len,
+            sync_word=sync_word,
+            tx_power_dbm=tx_power_dbm,
+            header_mode=header_mode,
+            payload_crc=bool(data[13]),
+            iq_invert=bool(data[14]),
+        )
+
+
+# ── FSK / GFSK config ──────────────────────────────────────────────
+
+
+@dataclass(frozen=True)
+class FskConfig:
+    """FSK / GFSK modulation parameters. Wire size ``16 + sync_word_len``."""
+
+    freq_hz: int
+    bitrate_bps: int
+    freq_dev_hz: int
+    rx_bw: int  # chip-specific enum index
+    preamble_len: int = 16
+    sync_word: bytes = b""  # 0-8 bytes
+
+    def encode(self) -> bytes:
+        if len(self.sync_word) > 8:
+            raise ValueError("FSK sync word max 8 bytes")
+        return (
+            struct.pack("<I", self.freq_hz)
+            + struct.pack("<I", self.bitrate_bps)
+            + struct.pack("<I", self.freq_dev_hz)
+            + bytes([self.rx_bw])
+            + struct.pack("<H", self.preamble_len)
+            + bytes([len(self.sync_word)])
+            + self.sync_word
+        )
+
+    @classmethod
+    def decode(cls, data: bytes) -> FskConfig:
+        if len(data) < 16:
+            raise ValueError(f"FskConfig too short: {len(data)}")
+        (freq_hz,) = struct.unpack_from("<I", data, 0)
+        (bitrate_bps,) = struct.unpack_from("<I", data, 4)
+        (freq_dev_hz,) = struct.unpack_from("<I", data, 8)
+        rx_bw = data[12]
+        (preamble_len,) = struct.unpack_from("<H", data, 13)
+        sync_word_len = data[15]
+        if sync_word_len > 8:
+            raise ValueError(f"FSK sync_word_len out of range: {sync_word_len}")
+        if len(data) != 16 + sync_word_len:
+            raise ValueError(f"FskConfig wrong total length: {len(data)}")
+        return cls(
+            freq_hz=freq_hz,
+            bitrate_bps=bitrate_bps,
+            freq_dev_hz=freq_dev_hz,
+            rx_bw=rx_bw,
+            preamble_len=preamble_len,
+            sync_word=bytes(data[16 : 16 + sync_word_len]),
+        )
+
+
+# ── LR-FHSS config ─────────────────────────────────────────────────
+
+
+class LrFhssBandwidth(enum.IntEnum):
+    KHZ_39 = 0
+    KHZ_86 = 1
+    KHZ_137 = 2
+    KHZ_184 = 3
+    KHZ_336 = 4
+    KHZ_387 = 5
+    KHZ_723 = 6
+    KHZ_1523 = 7
+
+
+class LrFhssCodingRate(enum.IntEnum):
+    CR_5_6 = 0
+    CR_2_3 = 1
+    CR_1_2 = 2
+    CR_1_3 = 3
+
+
+class LrFhssGrid(enum.IntEnum):
+    KHZ_25 = 0
+    KHZ_3_9 = 1
+
+
+@dataclass(frozen=True)
+class LrFhssConfig:
+    """LR-FHSS modulation parameters. 10-byte wire struct. TX-only on all
+    current Semtech silicon.
+    """
+
+    freq_hz: int
+    bw: LrFhssBandwidth
+    cr: LrFhssCodingRate
+    grid: LrFhssGrid
+    hopping: bool = True
+    tx_power_dbm: int = 14
+
+    def encode(self) -> bytes:
+        return (
+            struct.pack("<I", self.freq_hz)
+            + bytes([int(self.bw), int(self.cr), int(self.grid)])
+            + bytes([1 if self.hopping else 0])
+            + struct.pack("<b", self.tx_power_dbm)
+            + b"\x00"  # reserved
+        )
+
+    @classmethod
+    def decode(cls, data: bytes) -> LrFhssConfig:
+        if len(data) != 10:
+            raise ValueError(f"LrFhssConfig wire size must be 10 bytes, got {len(data)}")
+        (freq_hz,) = struct.unpack_from("<I", data, 0)
+        bw = LrFhssBandwidth(data[4])
+        cr = LrFhssCodingRate(data[5])
+        grid = LrFhssGrid(data[6])
+        if data[7] not in (0, 1):
+            raise ValueError("hopping must be 0 or 1")
+        (tx_power_dbm,) = struct.unpack_from("<b", data, 8)
+        if data[9] != 0:
+            raise ValueError("LR-FHSS reserved byte must be 0")
+        return cls(
+            freq_hz=freq_hz,
+            bw=bw,
+            cr=cr,
+            grid=grid,
+            hopping=bool(data[7]),
+            tx_power_dbm=tx_power_dbm,
+        )
+
+
+# ── FLRC config ────────────────────────────────────────────────────
+
+
+class FlrcBitrate(enum.IntEnum):
+    KBPS_2600 = 0
+    KBPS_2080 = 1
+    KBPS_1300 = 2
+    KBPS_1040 = 3
+    KBPS_650 = 4
+    KBPS_520 = 5
+    KBPS_325 = 6
+    KBPS_260 = 7
+
+
+class FlrcCodingRate(enum.IntEnum):
+    CR_1_2 = 0
+    CR_3_4 = 1
+    CR_1_1 = 2
+
+
+class FlrcBt(enum.IntEnum):
+    OFF = 0
+    BT_0_5 = 1
+    BT_1_0 = 2
+
+
+class FlrcPreambleLen(enum.IntEnum):
+    BITS_8 = 0
+    BITS_12 = 1
+    BITS_16 = 2
+    BITS_20 = 3
+    BITS_24 = 4
+    BITS_28 = 5
+    BITS_32 = 6
+
+
+@dataclass(frozen=True)
+class FlrcConfig:
+    """FLRC modulation parameters. 13-byte wire struct. SX128x / LR2021 only."""
+
+    freq_hz: int
+    bitrate: FlrcBitrate
+    cr: FlrcCodingRate
+    bt: FlrcBt
+    preamble_len: FlrcPreambleLen
+    sync_word: int  # 32-bit, transmitted MSB-first on air
+    tx_power_dbm: int = 14
+
+    def encode(self) -> bytes:
+        return (
+            struct.pack("<I", self.freq_hz)
+            + bytes(
+                [
+                    int(self.bitrate),
+                    int(self.cr),
+                    int(self.bt),
+                    int(self.preamble_len),
+                ],
+            )
+            + struct.pack("<I", self.sync_word)
+            + struct.pack("<b", self.tx_power_dbm)
+        )
+
+    @classmethod
+    def decode(cls, data: bytes) -> FlrcConfig:
+        if len(data) != 13:
+            raise ValueError(f"FlrcConfig wire size must be 13 bytes, got {len(data)}")
+        (freq_hz,) = struct.unpack_from("<I", data, 0)
+        bitrate = FlrcBitrate(data[4])
+        cr = FlrcCodingRate(data[5])
+        bt = FlrcBt(data[6])
+        preamble_len = FlrcPreambleLen(data[7])
+        (sync_word,) = struct.unpack_from("<I", data, 8)
+        (tx_power_dbm,) = struct.unpack_from("<b", data, 12)
+        return cls(
+            freq_hz=freq_hz,
+            bitrate=bitrate,
+            cr=cr,
+            bt=bt,
+            preamble_len=preamble_len,
+            sync_word=sync_word,
+            tx_power_dbm=tx_power_dbm,
+        )
+
+
+# ── Sum type for SET_CONFIG payloads ───────────────────────────────
+
+Modulation = LoRaConfig | FskConfig | LrFhssConfig | FlrcConfig
+
+
+def encode_modulation(mod: Modulation) -> bytes:
+    """Encode a modulation-agnostic ``[modulation_id || params]`` payload."""
+    if isinstance(mod, LoRaConfig):
+        return bytes([ModulationId.LORA]) + mod.encode()
+    if isinstance(mod, FskConfig):
+        return bytes([ModulationId.FSK_GFSK]) + mod.encode()
+    if isinstance(mod, LrFhssConfig):
+        return bytes([ModulationId.LR_FHSS]) + mod.encode()
+    if isinstance(mod, FlrcConfig):
+        return bytes([ModulationId.FLRC]) + mod.encode()
+    raise TypeError(f"unknown modulation type: {type(mod)}")
+
+
+def decode_modulation(data: bytes) -> Modulation:
+    if not data:
+        raise ValueError("modulation payload is empty")
+    mod_id = data[0]
+    params = data[1:]
+    if mod_id == ModulationId.LORA:
+        return LoRaConfig.decode(params)
+    if mod_id == ModulationId.FSK_GFSK:
+        return FskConfig.decode(params)
+    if mod_id == ModulationId.LR_FHSS:
+        return LrFhssConfig.decode(params)
+    if mod_id == ModulationId.FLRC:
+        return FlrcConfig.decode(params)
+    raise ValueError(f"unknown modulation_id: 0x{mod_id:02X}")

donglora/protocol.py

@@ -1,234 +0,0 @@
-"""Wire protocol types and fixed-size little-endian serialization.
-
-Mirrors the firmware's protocol and the Rust client's ``protocol.rs``
-using Python types.  Every integer is fixed-width LE.
-"""
-
-from __future__ import annotations
-
-import enum
-import struct
-from typing import Any, TypedDict
-
-# ── Size constants ────────────────────────────────────────────────
-
-MAX_PAYLOAD: int = 256
-"""Maximum LoRa payload size in bytes."""
-
-RADIO_CONFIG_SIZE: int = 13
-"""RadioConfig wire size (fixed)."""
-
-TX_POWER_MAX: int = -128
-"""Sentinel: set TX power to the board's maximum (i8::MIN on the wire)."""
-
-PREAMBLE_DEFAULT: int = 0
-"""Sentinel: use firmware default preamble length (16 symbols)."""
-
-# ── Tag constants ─────────────────────────────────────────────────
-
-CMD_TAG_PING: int = 0
-CMD_TAG_GET_CONFIG: int = 1
-CMD_TAG_SET_CONFIG: int = 2
-CMD_TAG_START_RX: int = 3
-CMD_TAG_STOP_RX: int = 4
-CMD_TAG_TRANSMIT: int = 5
-CMD_TAG_DISPLAY_ON: int = 6
-CMD_TAG_DISPLAY_OFF: int = 7
-CMD_TAG_GET_MAC: int = 8
-
-RESP_TAG_PONG: int = 0
-RESP_TAG_CONFIG: int = 1
-RESP_TAG_RX_PACKET: int = 2
-RESP_TAG_TX_DONE: int = 3
-RESP_TAG_OK: int = 4
-RESP_TAG_ERROR: int = 5
-RESP_TAG_MAC_ADDRESS: int = 6
-
-# ── Enums ─────────────────────────────────────────────────────────
-
-
-class Bandwidth(enum.IntEnum):
-    """LoRa signal bandwidth."""
-
-    Khz7 = 0
-    Khz10 = 1
-    Khz15 = 2
-    Khz20 = 3
-    Khz31 = 4
-    Khz41 = 5
-    Khz62 = 6
-    Khz125 = 7
-    Khz250 = 8
-    Khz500 = 9
-
-
-class ErrorCode(enum.IntEnum):
-    """Error codes reported by the firmware."""
-
-    InvalidConfig = 0
-    RadioBusy = 1
-    TxTimeout = 2
-    CrcError = 3
-    NotConfigured = 4
-    NoDisplay = 5
-
-
-ERROR_INVALID_CONFIG: int = ErrorCode.InvalidConfig
-ERROR_RADIO_BUSY: int = ErrorCode.RadioBusy
-ERROR_TX_TIMEOUT: int = ErrorCode.TxTimeout
-ERROR_NOT_CONFIGURED: int = ErrorCode.NotConfigured
-ERROR_NO_DISPLAY: int = ErrorCode.NoDisplay
-
-# ── RadioConfig ───────────────────────────────────────────────────
-
-
-class RadioConfig(TypedDict):
-    """Complete LoRa radio configuration.
-
-    Wire layout (13 bytes, all little-endian)::
-
-        [freq_hz:4] [bw:1] [sf:1] [cr:1] [sync_word:2]
-        [tx_power_dbm:1] [preamble_len:2] [cad:1]
-    """
-
-    freq_hz: int
-    bw: int
-    sf: int
-    cr: int
-    sync_word: int
-    tx_power_dbm: int
-    preamble_len: int
-    cad: int
-
-
-DEFAULT_CONFIG: RadioConfig = {
-    "freq_hz": 915_000_000,
-    "bw": Bandwidth.Khz125,
-    "sf": 7,
-    "cr": 5,
-    "sync_word": 0x1424,
-    "tx_power_dbm": TX_POWER_MAX,
-    "preamble_len": PREAMBLE_DEFAULT,
-    "cad": 1,
-}
-"""Default radio config: 915 MHz, 125 kHz BW, SF7, CR 4/5, max power, CAD on."""
-
-# ── Config wire encoding ──────────────────────────────────────────
-
-_CONFIG_STRUCT = struct.Struct("<IBBBHBHB")
-
-
-def encode_config(cfg: RadioConfig) -> bytes:
-    """Encode a RadioConfig to 13 fixed-size LE bytes."""
-    return _CONFIG_STRUCT.pack(
-        cfg["freq_hz"],
-        cfg["bw"],
-        cfg["sf"],
-        cfg["cr"],
-        cfg["sync_word"],
-        cfg["tx_power_dbm"] & 0xFF,
-        cfg.get("preamble_len", PREAMBLE_DEFAULT),
-        cfg.get("cad", 1),
-    )
-
-
-def decode_config(data: bytes) -> RadioConfig | None:
-    """Decode a RadioConfig from 13 LE bytes.  Returns ``None`` if too short or invalid."""
-    if len(data) < RADIO_CONFIG_SIZE:
-        return None
-    freq_hz, bw_raw, sf, cr, sync_word, _pwr_unsigned, preamble_len, cad = (
-        _CONFIG_STRUCT.unpack_from(data, 0)
-    )
-    try:
-        Bandwidth(bw_raw)
-    except ValueError:
-        return None
-    tx_power_dbm = struct.unpack_from("<b", data, 9)[0]
-    return {
-        "freq_hz": freq_hz,
-        "bw": bw_raw,
-        "sf": sf,
-        "cr": cr,
-        "sync_word": sync_word,
-        "tx_power_dbm": tx_power_dbm,
-        "preamble_len": preamble_len,
-        "cad": cad,
-    }
-
-
-# ── Command encoding ──────────────────────────────────────────────
-
-_COMMAND_TAGS: dict[str, int] = {
-    "Ping": CMD_TAG_PING,
-    "GetConfig": CMD_TAG_GET_CONFIG,
-    "SetConfig": CMD_TAG_SET_CONFIG,
-    "StartRx": CMD_TAG_START_RX,
-    "StopRx": CMD_TAG_STOP_RX,
-    "Transmit": CMD_TAG_TRANSMIT,
-    "DisplayOn": CMD_TAG_DISPLAY_ON,
-    "DisplayOff": CMD_TAG_DISPLAY_OFF,
-    "GetMac": CMD_TAG_GET_MAC,
-}
-
-
-def encode_command(cmd: str, **kwargs: Any) -> bytes:
-    """Encode a command to fixed-size LE bytes.
-
-    Raises ``ValueError`` for unknown commands or oversized payloads.
-    """
-    tag = _COMMAND_TAGS.get(cmd)
-    if tag is None:
-        raise ValueError(f"unknown command: {cmd!r}")
-    out = bytes([tag])
-    if cmd == "SetConfig":
-        out += encode_config(kwargs["config"])
-    elif cmd == "Transmit":
-        config: RadioConfig | None = kwargs.get("config")
-        if config is None:
-            out += b"\x00"
-        else:
-            out += b"\x01" + encode_config(config)
-        payload: bytes = kwargs["payload"]
-        if len(payload) > MAX_PAYLOAD:
-            raise ValueError(f"payload too large ({len(payload)} bytes, max {MAX_PAYLOAD})")
-        out += struct.pack("<H", len(payload)) + payload
-    return out
-
-
-# ── Response decoding ─────────────────────────────────────────────
-
-
-def decode_response(data: bytes) -> dict[str, Any]:
-    """Decode a fixed-size LE response into a dict."""
-    if not data:
-        return {"type": "Empty"}
-    tag = data[0]
-    rest = data[1:]
-    if tag == RESP_TAG_PONG:
-        return {"type": "Pong"}
-    if tag == RESP_TAG_CONFIG:
-        cfg = decode_config(rest)
-        if cfg is not None:
-            return {"type": "Config", **cfg}
-        return {"type": "Config", "raw": rest.hex()}
-    if tag == RESP_TAG_RX_PACKET:
-        if len(rest) < 6:
-            return {"type": "RxPacket", "rssi": 0, "snr": 0, "payload": b""}
-        rssi = struct.unpack_from("<h", rest, 0)[0]
-        snr = struct.unpack_from("<h", rest, 2)[0]
-        plen = struct.unpack_from("<H", rest, 4)[0]
-        payload = rest[6 : 6 + plen]
-        return {"type": "RxPacket", "rssi": rssi, "snr": snr, "payload": payload}
-    if tag == RESP_TAG_TX_DONE:
-        return {"type": "TxDone"}
-    if tag == RESP_TAG_OK:
-        return {"type": "Ok"}
-    if tag == RESP_TAG_ERROR:
-        code = rest[0] if rest else -1
-        return {"type": "Error", "code": code}
-    if tag == RESP_TAG_MAC_ADDRESS:
-        if len(rest) >= 6:
-            mac = ":".join(f"{b:02X}" for b in rest[:6])
-            return {"type": "MacAddress", "mac": mac}
-        return {"type": "MacAddress", "raw": rest.hex()}
-    return {"type": f"Unknown({tag})"}

donglora/session.py

@@ -0,0 +1,371 @@
+"""Internal session plumbing: tag counter, outstanding-tag correlation,
+background reader thread, async event queue.
+
+Not exposed to end users — :class:`donglora.dongle.Dongle` owns a
+Session and handles all request/response traffic through it.
+"""
+
+from __future__ import annotations
+
+import logging
+import queue
+import threading
+from dataclasses import dataclass
+from typing import Any
+
+from donglora.commands import (
+    TYPE_PING,
+    encode_get_info_payload,
+    encode_ping_payload,
+    encode_rx_start_payload,
+    encode_rx_stop_payload,
+    encode_set_config_payload,
+    encode_tx_payload,
+)
+from donglora.errors import (
+    DongloraError,
+    ErrorCode,
+    FrameError,
+    TimeoutError_,
+    device_error,
+)
+from donglora.events import (
+    TYPE_ERR,
+    TYPE_OK,
+    TYPE_RX,
+    TYPE_TX_DONE,
+    RxEvent,
+    TxDone,
+    decode_err_payload,
+    parse_ok_payload,
+)
+from donglora.frame import (
+    Frame,
+    encode_frame,
+    read_frame,
+)
+from donglora.frame import (
+    FrameError as FrameCodecError,
+)
+from donglora.modulation import Modulation
+
+log = logging.getLogger("donglora.session")
+
+
+# Sentinel placed on ``_rx_queue`` when the reader thread exits, so any
+# blocked ``next_rx`` caller unblocks promptly instead of waiting out
+# its full timeout. The sentinel is filtered out before reaching user
+# code.
+_DEAD_SENTINEL: object = object()
+
+
+# ── Pending-command tracking ───────────────────────────────────────
+
+
+@dataclass
+class _Pending:
+    """One outstanding command awaiting a response."""
+
+    tag: int
+    cmd_type: int
+    event: threading.Event
+    # Result slots (one of these is filled by the reader thread):
+    ok_payload: Any = None  # parsed OK payload (None for empty OKs)
+    err: DongloraError | None = None
+    tx_done: TxDone | None = None  # only for TX
+    # TX commands get two responses: OK (enqueued) then TX_DONE. The
+    # event is signalled after TX_DONE for TX; after OK/ERR for others.
+
+
+class Session:
+    """Owns the transport, demultiplexes inbound frames, correlates tags
+    to pending commands, queues async events.
+
+    Public API is thread-safe.
+    """
+
+    def __init__(self, transport: Any):
+        self._transport = transport
+        self._transport_lock = threading.Lock()
+
+        # Tag generator: monotonic u16, skips 0.
+        self._next_tag = 1
+        self._tag_lock = threading.Lock()
+
+        # Outstanding commands by tag.
+        self._pending: dict[int, _Pending] = {}
+        self._pending_lock = threading.Lock()
+
+        # Async RX events + async ERR frames. The queue may also hold
+        # `_DEAD_SENTINEL` to signal reader death without a user value.
+        self._rx_queue: queue.Queue[Any] = queue.Queue()
+        self._async_errors: queue.Queue[DongloraError] = queue.Queue()
+
+        # Reader thread. `_reader_dead` fires when the reader loop
+        # exits for any reason (transport closed, session closed,
+        # unexpected exception). The Dongle watches this to drive
+        # transparent reconnect.
+        self._closed = threading.Event()
+        self._reader_dead = threading.Event()
+        self._reader = threading.Thread(
+            target=self._reader_loop,
+            name="donglora-reader",
+            daemon=True,
+        )
+        self._reader.start()
+
+    # ── Public: send / send_tx / rx / close ──────────────────────────
+
+    def close(self) -> None:
+        self._closed.set()
+        # Wake any pending commands so they don't hang forever.
+        with self._pending_lock:
+            for p in self._pending.values():
+                p.err = DongloraError("session closed")
+                p.event.set()
+            self._pending.clear()
+        # Close the underlying transport so the reader thread's blocking
+        # read unblocks and it can exit cleanly.
+        import contextlib as _contextlib
+
+        with _contextlib.suppress(Exception):
+            self._transport.close()
+
+    @property
+    def is_alive(self) -> bool:
+        """True while the reader thread is running and no close was requested."""
+        return not self._reader_dead.is_set() and not self._closed.is_set()
+
+    @property
+    def reader_dead_event(self) -> threading.Event:
+        """Event that fires when the reader thread exits (for any reason)."""
+        return self._reader_dead
+
+    def ping(self, *, timeout: float = 2.0) -> None:
+        self._send_and_wait(TYPE_PING, encode_ping_payload(), timeout=timeout)
+
+    def get_info(self, *, timeout: float = 2.0):
+        return self._send_and_wait(0x02, encode_get_info_payload(), timeout=timeout)
+
+    def set_config(self, modulation: Modulation, *, timeout: float = 2.0):
+        return self._send_and_wait(
+            0x03,
+            encode_set_config_payload(modulation),
+            timeout=timeout,
+        )
+
+    def transmit(self, data: bytes, *, skip_cad: bool = False, timeout: float = 10.0) -> TxDone:
+        return self._send_tx(data, skip_cad=skip_cad, timeout=timeout)
+
+    def rx_start(self, *, timeout: float = 2.0) -> None:
+        self._send_and_wait(0x05, encode_rx_start_payload(), timeout=timeout)
+
+    def rx_stop(self, *, timeout: float = 2.0) -> None:
+        self._send_and_wait(0x06, encode_rx_stop_payload(), timeout=timeout)
+
+    def next_rx(self, timeout: float | None) -> RxEvent | None:
+        """Pop the next RX event from the queue, or ``None`` on timeout.
+
+        ``timeout=None`` blocks forever. Returns ``None`` if the reader
+        thread has died — the caller (normally :class:`Dongle`) should
+        then trigger a reconnect.
+        """
+        try:
+            item = self._rx_queue.get(block=True, timeout=timeout)
+        except queue.Empty:
+            return None
+        if item is _DEAD_SENTINEL:
+            # Reader is gone — re-post the sentinel for any other
+            # waiters and return None.
+            self._rx_queue.put(_DEAD_SENTINEL)
+            return None
+        return item
+
+    def drain_async_errors(self) -> list[DongloraError]:
+        """Return and clear any async errors observed since the last call."""
+        drained = []
+        while True:
+            try:
+                drained.append(self._async_errors.get_nowait())
+            except queue.Empty:
+                break
+        return drained
+
+    # ── Internal: send machinery ─────────────────────────────────────
+
+    def _alloc_tag(self) -> int:
+        with self._tag_lock:
+            tag = self._next_tag
+            self._next_tag = (tag + 1) & 0xFFFF
+            if self._next_tag == 0:
+                self._next_tag = 1
+            return tag
+
+    def _write_frame(self, type_id: int, tag: int, payload: bytes) -> None:
+        wire = encode_frame(type_id, tag, payload)
+        with self._transport_lock:
+            self._transport.write(wire)
+            flush = getattr(self._transport, "flush", None)
+            if callable(flush):
+                flush()
+
+    def _register_pending(self, tag: int, cmd_type: int) -> _Pending:
+        p = _Pending(tag=tag, cmd_type=cmd_type, event=threading.Event())
+        with self._pending_lock:
+            self._pending[tag] = p
+        return p
+
+    def _forget_pending(self, tag: int) -> None:
+        with self._pending_lock:
+            self._pending.pop(tag, None)
+
+    def _send_and_wait(self, type_id: int, payload: bytes, *, timeout: float) -> Any:
+        tag = self._alloc_tag()
+        pending = self._register_pending(tag, type_id)
+        try:
+            self._write_frame(type_id, tag, payload)
+            if not pending.event.wait(timeout=timeout):
+                raise TimeoutError_(f"command 0x{type_id:02X} tag={tag} timed out")
+            if pending.err is not None:
+                raise pending.err
+            return pending.ok_payload
+        finally:
+            self._forget_pending(tag)
+
+    def _send_tx(self, data: bytes, *, skip_cad: bool, timeout: float) -> TxDone:
+        """TX has a two-step completion: OK (enqueued) then TX_DONE.
+
+        We re-use the same pending slot for both: the reader flags ``err``
+        (early ERR during enqueue) or ``tx_done`` (after TX_DONE arrives)
+        and signals the event. We skip the intermediate OK entirely — the
+        reader treats the OK as "keep waiting for TX_DONE" on this tag.
+        """
+        tag = self._alloc_tag()
+        pending = self._register_pending(tag, 0x04)
+        try:
+            self._write_frame(0x04, tag, encode_tx_payload(data, skip_cad=skip_cad))
+            if not pending.event.wait(timeout=timeout):
+                raise TimeoutError_(f"TX tag={tag} timed out waiting for TX_DONE")
+            if pending.err is not None:
+                raise pending.err
+            if pending.tx_done is None:
+                raise DongloraError("TX completed without TX_DONE (internal error)")
+            return pending.tx_done
+        finally:
+            self._forget_pending(tag)
+
+    # ── Reader thread ────────────────────────────────────────────────
+
+    def _reader_loop(self) -> None:
+        try:
+            while not self._closed.is_set():
+                try:
+                    frame = read_frame(self._transport)
+                except FrameCodecError as exc:
+                    # CRC/COBS/length failure on an inbound frame. Surface as
+                    # an async error so the caller can see it.
+                    log.debug("inbound frame error: %s", exc)
+                    self._async_errors.put(FrameError(str(exc)))
+                    continue
+                except OSError:
+                    # Transport dropped (USB unplug, socket closed, etc.).
+                    if not self._closed.is_set():
+                        log.debug("session reader: transport closed")
+                    return
+                if frame is None:
+                    # Transport timeout — loop and keep reading.
+                    continue
+                try:
+                    self._dispatch(frame)
+                except Exception as exc:
+                    log.exception("reader dispatch failed: %s", exc)
+        finally:
+            # Reader is going away — wake anyone still waiting so they
+            # don't hang on .event.wait() forever, and signal the
+            # Dongle so it can trigger transparent reconnect.
+            with self._pending_lock:
+                for p in self._pending.values():
+                    if p.err is None and p.tx_done is None:
+                        p.err = DongloraError("transport closed")
+                    p.event.set()
+                self._pending.clear()
+            self._reader_dead.set()
+            # Poison the RX queue with a sentinel so any blocked
+            # next_rx() unblocks promptly instead of waiting for its
+            # full timeout. The sentinel is filtered out in next_rx.
+            self._rx_queue.put(_DEAD_SENTINEL)
+
+    def _dispatch(self, frame: Frame) -> None:
+        type_id = frame.type_id
+        tag = frame.tag
+        payload = frame.payload
+
+        # Async events: tag==0 or RX (which always has tag 0).
+        if tag == 0:
+            if type_id == TYPE_RX:
+                try:
+                    rx = RxEvent.decode(payload)
+                except ValueError as exc:
+                    log.debug("bad RX event: %s", exc)
+                    self._async_errors.put(FrameError(f"bad RX payload: {exc}"))
+                    return
+                self._rx_queue.put(rx)
+                return
+            if type_id == TYPE_ERR:
+                code = decode_err_payload(payload)
+                self._async_errors.put(device_error(code, tag=0))
+                return
+            log.debug("unknown async frame type 0x%02X", type_id)
+            return
+
+        # Tag-correlated: OK / ERR / TX_DONE / RX-with-tag (never expected).
+        with self._pending_lock:
+            pending = self._pending.get(tag)
+        if pending is None:
+            log.debug("no pending command for tag 0x%04X (type 0x%02X)", tag, type_id)
+            return
+
+        if type_id == TYPE_OK:
+            try:
+                ok = parse_ok_payload(pending.cmd_type, payload)
+            except (ValueError, KeyError) as exc:
+                pending.err = DongloraError(f"bad OK payload: {exc}")
+                pending.event.set()
+                return
+            if pending.cmd_type == 0x04:
+                # TX: OK means "enqueued" — do NOT signal yet, wait for TX_DONE.
+                pending.ok_payload = ok
+                return
+            pending.ok_payload = ok
+            pending.event.set()
+            return
+
+        if type_id == TYPE_ERR:
+            code = decode_err_payload(payload)
+            pending.err = device_error(code, tag=tag)
+            pending.event.set()
+            return
+
+        if type_id == TYPE_TX_DONE:
+            try:
+                td = TxDone.decode(payload)
+            except ValueError as exc:
+                pending.err = DongloraError(f"bad TX_DONE payload: {exc}")
+                pending.event.set()
+                return
+            from donglora.errors import Cancelled, ChannelBusy
+            from donglora.events import TxResult
+
+            if td.result == TxResult.CHANNEL_BUSY:
+                pending.err = ChannelBusy()
+            elif td.result == TxResult.CANCELLED:
+                pending.err = Cancelled()
+            else:
+                pending.tx_done = td
+            pending.event.set()
+            return
+
+        log.debug("unexpected tag-correlated type 0x%02X for tag 0x%04X", type_id, tag)
+
+
+_ = ErrorCode  # re-export so users can still catch specific codes

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "donglora"
-version = "0.2.0"
+version = "1.1.0"
 description = "DongLoRa host library — talk LoRa from Python over USB"
 license = "MIT"
 requires-python = ">=3.10"
@@ -8,7 +8,7 @@ readme = "README.md"
 authors = [{ name = "Stephen Waits", email = "steve@waits.net" }]
 keywords = ["lora", "radio", "usb", "embedded", "serial"]
 classifiers = [
-    "Development Status :: 3 - Alpha",
+    "Development Status :: 5 - Production/Stable",
     "License :: OSI Approved :: MIT License",
     "Programming Language :: Python :: 3",
     "Programming Language :: Python :: 3.10",

tests/test_client.py

@@ -1,135 +0,0 @@
-"""Tests for donglora.client — send/recv/drain_rx/validate."""
-
-from __future__ import annotations
-
-import struct
-from io import BytesIO
-from typing import Any
-
-from donglora.client import _rx_queue, drain_rx, recv, send, validate
-from donglora.codec import cobs_encode
-
-
-def _make_mock(responses: list[bytes]) -> Any:
-    """Create a mock transport that returns pre-encoded COBS frames."""
-    wire = b""
-    for resp in responses:
-        wire += cobs_encode(resp)
-
-    class Mock:
-        def __init__(self) -> None:
-            self._stream = BytesIO(wire)
-            self.timeout = 2.0
-            self._written: list[bytes] = []
-
-        def read(self, n: int = 1) -> bytes:
-            return self._stream.read(n)
-
-        def write(self, data: bytes) -> int:
-            self._written.append(data)
-            return len(data)
-
-        def flush(self) -> None:
-            pass
-
-    return Mock()
-
-
-def _pong() -> bytes:
-    return bytes([0])
-
-
-def _ok() -> bytes:
-    return bytes([4])
-
-
-def _rx_packet(payload: bytes, rssi: int = -80, snr: int = 10) -> bytes:
-    return (
-        bytes([2])
-        + struct.pack("<h", rssi)
-        + struct.pack("<h", snr)
-        + struct.pack("<H", len(payload))
-        + payload
-    )
-
-
-class TestSend:
-    def setup_method(self) -> None:
-        _rx_queue.clear()
-
-    def test_basic_command(self) -> None:
-        mock = _make_mock([_pong()])
-        resp = send(mock, "Ping")
-        assert resp["type"] == "Pong"
-
-    def test_buffers_rx_packets(self) -> None:
-        mock = _make_mock([_rx_packet(b"pkt1"), _rx_packet(b"pkt2"), _ok()])
-        resp = send(mock, "StartRx")
-        assert resp["type"] == "Ok"
-        assert len(_rx_queue) == 2
-
-    def test_timeout(self) -> None:
-        mock = _make_mock([])
-        resp = send(mock, "Ping")
-        assert resp["type"] == "Timeout"
-
-
-class TestRecv:
-    def setup_method(self) -> None:
-        _rx_queue.clear()
-
-    def test_from_buffer(self) -> None:
-        _rx_queue.append({"type": "RxPacket", "rssi": -80, "snr": 10, "payload": b"buf"})
-        mock = _make_mock([])
-        pkt = recv(mock)
-        assert pkt is not None
-        assert pkt["payload"] == b"buf"
-
-    def test_from_wire(self) -> None:
-        mock = _make_mock([_rx_packet(b"wire")])
-        pkt = recv(mock)
-        assert pkt is not None
-        assert pkt["payload"] == b"wire"
-
-    def test_timeout(self) -> None:
-        mock = _make_mock([])
-        assert recv(mock) is None
-
-
-class TestDrainRx:
-    def setup_method(self) -> None:
-        _rx_queue.clear()
-
-    def test_drains_buffer_and_wire(self) -> None:
-        _rx_queue.append({"type": "RxPacket", "rssi": 0, "snr": 0, "payload": b"buf"})
-        mock = _make_mock([_rx_packet(b"wire")])
-        packets = drain_rx(mock)
-        assert len(packets) == 2
-        assert packets[0]["payload"] == b"buf"
-        assert packets[1]["payload"] == b"wire"
-        assert len(_rx_queue) == 0
-
-
-class TestValidate:
-    def setup_method(self) -> None:
-        _rx_queue.clear()
-
-    def test_success(self) -> None:
-        mock = _make_mock([_pong()])
-        validate(mock)
-
-    def test_failure(self) -> None:
-        mock = _make_mock([_ok()])
-        try:
-            validate(mock)
-            assert False, "should have raised"  # noqa: B011
-        except ConnectionError:
-            pass
-
-    def test_timeout(self) -> None:
-        mock = _make_mock([])
-        try:
-            validate(mock)
-            assert False, "should have raised"  # noqa: B011
-        except ConnectionError:
-            pass

tests/test_codec.py

@@ -1,12 +1,13 @@
-"""Tests for donglora.codec — COBS framing."""
+"""COBS helper tests — the thin re-export layer.
+
+Frame-level codec tests live in ``test_frame.py``.
+"""
 
 from __future__ import annotations
 
-from io import BytesIO
-
 from cobs import cobs
 
-from donglora.codec import cobs_encode, read_frame
+from donglora.codec import cobs_encode
 
 
 class TestCobsEncode:
@@ -34,42 +35,3 @@ class TestCobsEncode:
             encoded = cobs_encode(data)
             decoded = cobs.decode(encoded[:-1])
             assert decoded == data
-
-
-class _MockSerial:
-    """Minimal mock that behaves like serial.Serial for read_frame."""
-
-    def __init__(self, data: bytes) -> None:
-        self._stream = BytesIO(data)
-
-    def read(self, n: int = 1) -> bytes:
-        return self._stream.read(n)
-
-
-class TestReadFrame:
-    def test_basic(self) -> None:
-        data = b"hello"
-        frame = cobs_encode(data)
-        result = read_frame(_MockSerial(frame))
-        assert result == data
-
-    def test_timeout(self) -> None:
-        result = read_frame(_MockSerial(b""))
-        assert result is None
-
-    def test_empty_frame(self) -> None:
-        result = read_frame(_MockSerial(b"\x00"))
-        assert result is None
-
-    def test_corrupt_frame(self) -> None:
-        result = read_frame(_MockSerial(b"\xff\x00"))
-        # cobs.decode of [0xff] may or may not raise — just verify we get bytes or None
-        assert result is None or isinstance(result, bytes)
-
-    def test_multiple_frames(self) -> None:
-        frame1 = cobs_encode(b"first")
-        frame2 = cobs_encode(b"second")
-        mock = _MockSerial(frame1 + frame2)
-        assert read_frame(mock) == b"first"
-        assert read_frame(mock) == b"second"
-        assert read_frame(mock) is None

tests/test_connect.py

@@ -0,0 +1,196 @@
+"""Unit tests for the client-side config preparation done by ``connect()``.
+
+Validates the auto_configure contract:
+
+* ``tx_power_dbm`` clamps silently (both high and low sides).
+* ``freq_hz`` / ``sf`` / ``bw`` raise :class:`ConfigNotSupported` when
+  outside the device's advertised caps — silent substitution would hide
+  regulatory or airtime-changing surprises from the caller.
+* Non-LoRa modulations pass through untouched.
+"""
+
+from __future__ import annotations
+
+import pytest
+
+import donglora as dl
+from donglora.connect import _prepare_config
+from donglora.info import Info
+
+
+def _info(
+    *,
+    freq_min_hz: int = 863_000_000,
+    freq_max_hz: int = 928_000_000,
+    supported_sf_bitmap: int = 0x1FE0,  # SF5..SF12
+    supported_bw_bitmap: int = 0x03FF,  # sub-GHz BWs 0..9
+    tx_power_min_dbm: int = -9,
+    tx_power_max_dbm: int = 22,
+) -> Info:
+    """Build an Info with only the caps-related fields that matter here."""
+    return Info(
+        proto_major=1,
+        proto_minor=0,
+        fw_major=0,
+        fw_minor=0,
+        fw_patch=0,
+        radio_chip_id=int(dl.RadioChipId.SX1262),
+        capability_bitmap=dl.Capability.LORA,
+        supported_sf_bitmap=supported_sf_bitmap,
+        supported_bw_bitmap=supported_bw_bitmap,
+        max_payload_bytes=255,
+        rx_queue_capacity=32,
+        tx_queue_capacity=1,
+        freq_min_hz=freq_min_hz,
+        freq_max_hz=freq_max_hz,
+        tx_power_min_dbm=tx_power_min_dbm,
+        tx_power_max_dbm=tx_power_max_dbm,
+        mcu_uid=b"\x00" * 6,
+        radio_uid=b"",
+    )
+
+
+# ── tx_power: clamp silently ──────────────────────────────────────
+
+
+def test_tx_power_above_max_is_clamped_down():
+    cfg = dl.LoRaConfig.default()
+    cfg = dl.LoRaConfig(
+        freq_hz=cfg.freq_hz,
+        bw=cfg.bw,
+        sf=cfg.sf,
+        cr=cfg.cr,
+        sync_word=cfg.sync_word,
+        tx_power_dbm=30,
+        preamble_len=cfg.preamble_len,
+        header_mode=cfg.header_mode,
+        payload_crc=cfg.payload_crc,
+        iq_invert=cfg.iq_invert,
+    )
+    out = _prepare_config(_info(tx_power_max_dbm=20), cfg)
+    assert isinstance(out, dl.LoRaConfig)
+    assert out.tx_power_dbm == 20
+    # Other fields unchanged.
+    assert out.freq_hz == cfg.freq_hz
+    assert out.sf == cfg.sf
+
+
+def test_tx_power_below_min_is_clamped_up():
+    cfg = dl.LoRaConfig.default()
+    cfg = dl.LoRaConfig(
+        freq_hz=cfg.freq_hz,
+        bw=cfg.bw,
+        sf=cfg.sf,
+        cr=cfg.cr,
+        sync_word=cfg.sync_word,
+        tx_power_dbm=-30,
+        preamble_len=cfg.preamble_len,
+        header_mode=cfg.header_mode,
+        payload_crc=cfg.payload_crc,
+        iq_invert=cfg.iq_invert,
+    )
+    out = _prepare_config(_info(tx_power_min_dbm=2), cfg)
+    assert isinstance(out, dl.LoRaConfig)
+    assert out.tx_power_dbm == 2
+
+
+def test_tx_power_inside_range_is_untouched():
+    cfg = dl.LoRaConfig.default()
+    out = _prepare_config(_info(), cfg)
+    assert out is cfg  # same object, no replace() called
+
+
+# ── freq_hz: reject (regulatory boundaries) ───────────────────────
+
+
+def test_freq_below_min_raises():
+    cfg = dl.LoRaConfig(
+        freq_hz=300_000_000,
+        bw=dl.LoRaBandwidth.KHZ_125,
+        sf=7,
+        cr=dl.LoRaCodingRate.CR_4_5,
+        sync_word=0x3444,
+        tx_power_dbm=14,
+        preamble_len=8,
+        header_mode=dl.LoRaHeaderMode.EXPLICIT,
+        payload_crc=True,
+        iq_invert=False,
+    )
+    with pytest.raises(dl.ConfigNotSupported, match="frequency"):
+        _prepare_config(_info(freq_min_hz=863_000_000, freq_max_hz=928_000_000), cfg)
+
+
+def test_freq_above_max_raises():
+    cfg = dl.LoRaConfig(
+        freq_hz=2_400_000_000,
+        bw=dl.LoRaBandwidth.KHZ_125,
+        sf=7,
+        cr=dl.LoRaCodingRate.CR_4_5,
+        sync_word=0x3444,
+        tx_power_dbm=14,
+        preamble_len=8,
+        header_mode=dl.LoRaHeaderMode.EXPLICIT,
+        payload_crc=True,
+        iq_invert=False,
+    )
+    with pytest.raises(dl.ConfigNotSupported, match="frequency"):
+        _prepare_config(_info(freq_min_hz=137_000_000, freq_max_hz=1_020_000_000), cfg)
+
+
+# ── sf: reject (airtime / sensitivity change) ─────────────────────
+
+
+def test_sf5_rejected_on_sx1276_bitmap():
+    """SX1276 advertises SF6-SF12 (0x1FC0). SF5 must not silently upgrade."""
+    cfg = dl.LoRaConfig(
+        freq_hz=915_000_000,
+        bw=dl.LoRaBandwidth.KHZ_125,
+        sf=5,
+        cr=dl.LoRaCodingRate.CR_4_5,
+        sync_word=0x3444,
+        tx_power_dbm=14,
+        preamble_len=8,
+        header_mode=dl.LoRaHeaderMode.EXPLICIT,
+        payload_crc=True,
+        iq_invert=False,
+    )
+    with pytest.raises(dl.ConfigNotSupported, match="SF5"):
+        _prepare_config(_info(supported_sf_bitmap=0x1FC0), cfg)
+
+
+# ── bw: reject (airtime change) ────────────────────────────────────
+
+
+def test_bw_not_in_bitmap_raises():
+    """SX128x-only 200 kHz BW on a sub-GHz-only device must be rejected."""
+    cfg = dl.LoRaConfig(
+        freq_hz=915_000_000,
+        bw=dl.LoRaBandwidth.KHZ_200,  # bit 10 — SX128x only
+        sf=7,
+        cr=dl.LoRaCodingRate.CR_4_5,
+        sync_word=0x3444,
+        tx_power_dbm=14,
+        preamble_len=8,
+        header_mode=dl.LoRaHeaderMode.EXPLICIT,
+        payload_crc=True,
+        iq_invert=False,
+    )
+    with pytest.raises(dl.ConfigNotSupported, match="bandwidth"):
+        _prepare_config(_info(supported_bw_bitmap=0x03FF), cfg)
+
+
+# ── Non-LoRa: pass through ─────────────────────────────────────────
+
+
+def test_non_lora_modulation_passes_through():
+    # Frequency deliberately outside the info's range; _prepare_config
+    # must not inspect it for non-LoRa modulations (firmware rejects
+    # unsupported modulation IDs with EMODULATION on its own).
+    fsk = dl.FskConfig(
+        freq_hz=50_000_000,
+        bitrate_bps=50_000,
+        freq_dev_hz=25_000,
+        rx_bw=0,
+    )
+    out = _prepare_config(_info(), fsk)
+    assert out is fsk

tests/test_crc.py

@@ -0,0 +1,23 @@
+"""CRC-16/CCITT-FALSE conformance tests."""
+
+from donglora.crc import crc16
+
+
+def test_check_value_matches_spec():
+    # PROTOCOL.md §2.2 / Appendix B.
+    assert crc16(b"123456789") == 0x29B1
+
+
+def test_empty_input_is_initial_value():
+    # No reflection, no XOR-out: empty leaves init untouched.
+    assert crc16(b"") == 0xFFFF
+
+
+def test_single_null_byte():
+    # A naive init=0 impl would yield 0; correct init=0xFFFF yields 0xE1F0.
+    assert crc16(b"\x00") == 0xE1F0
+
+
+def test_differs_from_kermit_variant():
+    # CRC-16/KERMIT of "123456789" is 0x2189.
+    assert crc16(b"123456789") != 0x2189

tests/test_dongle.py

@@ -0,0 +1,219 @@
+"""Dongle-level tests: keepalive thread, auto-recovery, context manager."""
+
+from __future__ import annotations
+
+import time
+
+import pytest
+
+from donglora.commands import TYPE_PING, TYPE_TX
+from donglora.dongle import Dongle
+from donglora.errors import DongloraError
+from donglora.events import (
+    TYPE_ERR,
+    TxResult,
+)
+from donglora.frame import encode_frame
+from donglora.modulation import LoRaConfig
+from donglora.session import Session
+from tests.test_session import FakeTransport, _default_script
+
+
+def _make_dongle(transport: FakeTransport) -> Dongle:
+    session = Session(transport)
+    info = session.get_info()
+    cfg = LoRaConfig.default()
+    session.set_config(cfg)
+    return Dongle(session, info, applied_config=cfg, keepalive=False)
+
+
+def test_dongle_tx_returns_tx_done():
+    t = FakeTransport()
+    try:
+        d = _make_dongle(t)
+        with d:
+            td = d.tx(b"hello")
+            assert td.airtime_us == 30_976
+    finally:
+        t.close()
+
+
+def test_dongle_info_property_exposes_cached_info():
+    t = FakeTransport()
+    try:
+        with _make_dongle(t) as d:
+            assert d.info.proto_major == 1
+    finally:
+        t.close()
+
+
+def test_dongle_auto_recovers_from_not_configured():
+    """First TX returns ENOTCONFIGURED; Dongle re-applies cached config,
+    then retries and succeeds.
+    """
+
+    class FlipScript:
+        def __init__(self):
+            self._first_tx = True
+
+        def __call__(self, type_id, tag, payload):
+            if type_id == TYPE_TX and self._first_tx:
+                self._first_tx = False
+                return [encode_frame(TYPE_ERR, tag, b"\x03\x00")]  # ENOTCONFIGURED
+            return _default_script(type_id, tag, payload)
+
+    t = FakeTransport(script=FlipScript())
+    try:
+        with _make_dongle(t) as d:
+            td = d.tx(b"retry-me")
+            assert td.result == TxResult.TRANSMITTED
+    finally:
+        t.close()
+
+
+def test_dongle_context_manager_closes_session():
+    t = FakeTransport()
+    try:
+        d = _make_dongle(t)
+        with d:
+            pass
+        # After exit, further operations raise DongloraError.
+        with pytest.raises(DongloraError):
+            d.tx(b"too-late")
+    finally:
+        t.close()
+
+
+def test_dongle_close_is_idempotent():
+    t = FakeTransport()
+    try:
+        d = _make_dongle(t)
+        d.close()
+        d.close()  # must not raise
+    finally:
+        t.close()
+
+
+def test_dongle_keepalive_daemon_sends_pings():
+    """With keepalive enabled, a quiet dongle emits PINGs at ~500ms cadence."""
+    t = FakeTransport()
+    try:
+        session = Session(t)
+        info = session.get_info()
+        cfg = LoRaConfig.default()
+        session.set_config(cfg)
+        # Record frames sent after setup. keepalive=True starts the
+        # background thread.
+        t.log.clear()
+        d = Dongle(session, info, applied_config=cfg, keepalive=True)
+        time.sleep(0.8)  # allow at least one keepalive interval
+        d.close()
+        # Expect at least one PING in the log.
+        from donglora.frame import decode_frame
+
+        ping_count = sum(1 for raw in t.log if decode_frame(raw).type_id == TYPE_PING)
+        assert ping_count >= 1
+    finally:
+        t.close()
+
+
+def test_dongle_config_property_tracks_set_config():
+    t = FakeTransport()
+    try:
+        with _make_dongle(t) as d:
+            assert d.config == LoRaConfig.default()
+            custom = LoRaConfig(
+                freq_hz=915_000_000,
+                sf=10,
+                bw=d.config.bw,
+                cr=d.config.cr,
+            )
+            d.set_config(custom)
+            assert d.config == custom
+    finally:
+        t.close()
+
+
+class _EOFTransport(FakeTransport):
+    """Like FakeTransport, but `read()` raises ConnectionError after close.
+
+    Matches the real-world ``MuxConnection.read`` / ``serial.Serial.read``
+    behaviour when the remote hangs up, which is what the Dongle's
+    transparent-reconnect path needs to see.
+    """
+
+    def read(self, n: int = 1) -> bytes:
+        data = super().read(n)
+        if not data and self._closed:
+            raise ConnectionError("transport closed")
+        return data
+
+
+def test_dongle_transparent_reconnect_on_session_death():
+    """When the session's reader dies (mux restart / transport blip),
+    the Dongle transparently reopens and a subsequent ``tx()`` call
+    just works. The caller never sees an exception.
+
+    Drives it with a reopener that returns a *fresh* transport for the
+    second connect — simulating the mux coming back up under a new
+    process with the original radio state intact.
+    """
+    # Transport #1 — will be "killed" mid-test to simulate mux death.
+    t1 = _EOFTransport()
+    # Transport #2 — stands in for the replacement mux coming back.
+    t2 = FakeTransport()
+
+    session1 = Session(t1)
+    info1 = session1.get_info()
+    cfg = LoRaConfig.default()
+    session1.set_config(cfg)
+
+    def reopener():
+        s = Session(t2)
+        i = s.get_info()
+        s.set_config(cfg)
+        return (s, i, cfg)
+
+    d = Dongle(
+        session1,
+        info1,
+        applied_config=cfg,
+        keepalive=False,
+        _reopener=reopener,
+    )
+    try:
+        # Sanity: first TX works through session #1.
+        assert d.tx(b"hi").result == TxResult.TRANSMITTED
+
+        # Simulate mux going away. Reader thread sees ConnectionError
+        # on its next read and exits.
+        t1.close()
+        # Give the reader a moment to notice.
+        time.sleep(0.2)
+
+        # Second TX MUST succeed — Dongle reconnects through the
+        # reopener transparently.
+        assert d.tx(b"after-reconnect").result == TxResult.TRANSMITTED
+        # And the cached config is preserved across reconnect.
+        assert d.config == cfg
+    finally:
+        d.close()
+        t2.close()
+
+
+def test_dongle_without_reopener_surfaces_dead_session():
+    """Manually-constructed Dongles (no reopener) must not swallow
+    session death — the caller gets a real error."""
+    t = _EOFTransport()
+    try:
+        session = Session(t)
+        info = session.get_info()
+        cfg = LoRaConfig.default()
+        session.set_config(cfg)
+        d = Dongle(session, info, applied_config=cfg, keepalive=False)  # no reopener
+        t.close()
+        time.sleep(0.2)  # let the reader die
+        with pytest.raises(DongloraError):
+            d.tx(b"no-reopener")
+    finally:
+        t.close()

tests/test_ergonomics.py

@@ -0,0 +1,75 @@
+"""Sanity check that the three-line happy path works.
+
+If these tests need anything beyond ``import donglora as dl`` + three
+method calls, the client lost its reason for existing.
+"""
+
+from __future__ import annotations
+
+import donglora as dl
+from donglora.events import TYPE_RX, RxOrigin
+
+
+def test_happy_path_tx_is_three_lines():
+    """Three lines: get a Dongle (from the test harness), tx, done."""
+    from donglora.dongle import Dongle
+    from donglora.modulation import LoRaConfig
+    from donglora.session import Session
+    from tests.test_session import FakeTransport
+
+    t = FakeTransport()
+    try:
+        session = Session(t)
+        info = session.get_info()
+        cfg = LoRaConfig.default()
+        session.set_config(cfg)
+        with Dongle(session, info, applied_config=cfg, keepalive=False) as d:
+            td = d.tx(b"Hello")
+            assert td.result.name == "TRANSMITTED"
+    finally:
+        t.close()
+
+
+def test_rx_iterator_yields_incoming_packets():
+    """The `.rx()` iterator terminates cleanly on timeout."""
+    from donglora.dongle import Dongle
+    from donglora.events import RxEvent
+    from donglora.modulation import LoRaConfig
+    from donglora.session import Session
+    from tests.test_session import FakeTransport
+
+    t = FakeTransport()
+    try:
+        session = Session(t)
+        info = session.get_info()
+        cfg = LoRaConfig.default()
+        session.set_config(cfg)
+        rx = RxEvent(
+            rssi_dbm=-72.0,
+            snr_db=8.0,
+            freq_err_hz=0,
+            timestamp_us=100,
+            crc_valid=True,
+            packets_dropped=0,
+            origin=RxOrigin.OTA,
+            data=b"ping",
+        )
+        with Dongle(session, info, applied_config=cfg, keepalive=False) as d:
+            # Inject two RX events, then time out.
+            t.push_async(TYPE_RX, 0, rx.encode())
+            t.push_async(TYPE_RX, 0, rx.encode())
+            received: list[bytes] = []
+            for pkt in d.rx(timeout=0.5):
+                received.append(pkt.data)
+                if len(received) == 2:
+                    break
+            assert received == [b"ping", b"ping"]
+    finally:
+        t.close()
+
+
+def test_public_api_names_are_stable():
+    # The top-level module exposes the core happy-path surface. If any
+    # of these disappear it's a breaking change we should notice.
+    for name in ("connect", "Dongle", "LoRaConfig", "tx", "rx", "recv"):
+        assert hasattr(dl, name), f"donglora.{name} must stay exported"

tests/test_events.py

@@ -0,0 +1,265 @@
+"""Event payload tests: Info, SetConfigResult, TxDone, RxEvent, ERR."""
+
+import pytest
+
+from donglora.commands import TYPE_PING, TYPE_SET_CONFIG
+from donglora.errors import ErrorCode
+from donglora.events import (
+    Owner,
+    RxEvent,
+    RxOrigin,
+    SetConfigResult,
+    SetConfigResultCode,
+    TxDone,
+    TxResult,
+    decode_err_payload,
+    encode_err_payload,
+    parse_ok_payload,
+)
+from donglora.info import Capability, Info, RadioChipId
+from donglora.modulation import LoRaConfig
+
+# ── SetConfigResult ───────────────────────────────────────────
+
+
+def test_set_config_result_c23_bytes():
+    # PROTOCOL.md §C.2.3: OK in reply to SET_CONFIG, LoRa applied.
+    r = SetConfigResult(
+        result=SetConfigResultCode.APPLIED,
+        owner=Owner.MINE,
+        current=LoRaConfig.default(),
+    )
+    expected = bytes(
+        [
+            0x00,
+            0x01,  # result=APPLIED, owner=MINE
+            0x01,  # modulation_id = LoRa
+            0xA0,
+            0x27,
+            0xBE,
+            0x33,  # freq
+            0x07,
+            0x07,
+            0x00,  # sf / bw / cr
+            0x08,
+            0x00,  # preamble_len
+            0x24,
+            0x14,  # sync_word
+            0x0E,  # tx_power
+            0x00,
+            0x01,
+            0x00,  # header / crc / iq
+        ],
+    )
+    assert r.encode() == expected
+    assert SetConfigResult.decode(expected) == r
+
+
+# ── TxDone ────────────────────────────────────────────────────
+
+
+def test_tx_done_transmitted_airtime():
+    td = TxDone(result=TxResult.TRANSMITTED, airtime_us=30_976)
+    assert td.encode() == bytes([0x00, 0x00, 0x79, 0x00, 0x00])
+    assert TxDone.decode(td.encode()) == td
+
+
+def test_tx_done_channel_busy():
+    td = TxDone(result=TxResult.CHANNEL_BUSY, airtime_us=0)
+    assert TxDone.decode(td.encode()) == td
+
+
+# ── RxEvent ───────────────────────────────────────────────────
+
+
+def test_rx_event_c26_bytes():
+    rx = RxEvent(
+        rssi_dbm=-73.5,
+        snr_db=9.5,
+        freq_err_hz=-125,
+        timestamp_us=42_000_000,
+        crc_valid=True,
+        packets_dropped=0,
+        origin=RxOrigin.OTA,
+        data=bytes([0x01, 0x02, 0x03, 0x04]),
+    )
+    # PROTOCOL.md §C.2.6 payload (strip frame header + CRC).
+    expected = bytes(
+        [
+            0x21,
+            0xFD,  # rssi = -735 LE
+            0x5F,
+            0x00,  # snr = 95 LE
+            0x83,
+            0xFF,
+            0xFF,
+            0xFF,  # freq_err = -125 LE
+            0x80,
+            0xDE,
+            0x80,
+            0x02,
+            0x00,
+            0x00,
+            0x00,
+            0x00,  # ts = 42_000_000 LE
+            0x01,  # crc_valid
+            0x00,
+            0x00,  # packets_dropped
+            0x00,  # origin OTA
+            0x01,
+            0x02,
+            0x03,
+            0x04,
+        ],
+    )
+    assert rx.encode() == expected
+    decoded = RxEvent.decode(expected)
+    assert decoded.rssi_dbm == pytest.approx(-73.5)
+    assert decoded.snr_db == pytest.approx(9.5)
+    assert decoded.data == bytes([0x01, 0x02, 0x03, 0x04])
+
+
+def test_rx_event_rejects_invalid_crc_byte():
+    buf = bytearray(
+        RxEvent(
+            rssi_dbm=0.0,
+            snr_db=0.0,
+            freq_err_hz=0,
+            timestamp_us=0,
+            crc_valid=True,
+            packets_dropped=0,
+            origin=RxOrigin.OTA,
+            data=b"",
+        ).encode(),
+    )
+    buf[16] = 2
+    with pytest.raises(ValueError):
+        RxEvent.decode(bytes(buf))
+
+
+# ── ERR payload ───────────────────────────────────────────────
+
+
+def test_err_payload_roundtrip():
+    wire = encode_err_payload(ErrorCode.ENOT_CONFIGURED)
+    assert wire == bytes([0x03, 0x00])
+    assert decode_err_payload(wire) == ErrorCode.ENOT_CONFIGURED
+
+
+def test_err_payload_preserves_unknown_code():
+    wire = encode_err_payload(0xABCD)
+    assert decode_err_payload(wire) == 0xABCD
+
+
+# ── OK payload context dispatch ───────────────────────────────
+
+
+def test_parse_ok_for_ping_requires_empty():
+    assert parse_ok_payload(TYPE_PING, b"") is None
+    with pytest.raises(ValueError):
+        parse_ok_payload(TYPE_PING, b"\x00")
+
+
+def test_parse_ok_for_set_config_returns_result():
+    r = SetConfigResult(
+        result=SetConfigResultCode.APPLIED,
+        owner=Owner.MINE,
+        current=LoRaConfig.default(),
+    )
+    parsed = parse_ok_payload(TYPE_SET_CONFIG, r.encode())
+    assert parsed == r
+
+
+# ── Info ──────────────────────────────────────────────────────
+
+
+def _sample_info() -> Info:
+    return Info(
+        proto_major=1,
+        proto_minor=0,
+        fw_major=0,
+        fw_minor=1,
+        fw_patch=0,
+        radio_chip_id=RadioChipId.SX1262,
+        capability_bitmap=Capability.LORA | Capability.FSK | Capability.CAD_BEFORE_TX,
+        supported_sf_bitmap=0x1FE0,
+        supported_bw_bitmap=0x03FF,
+        max_payload_bytes=255,
+        rx_queue_capacity=64,
+        tx_queue_capacity=16,
+        freq_min_hz=150_000_000,
+        freq_max_hz=960_000_000,
+        tx_power_min_dbm=-9,
+        tx_power_max_dbm=22,
+        mcu_uid=bytes([0xDE, 0xAD, 0xBE, 0xEF, 0x01, 0x23, 0x45, 0x67]),
+        radio_uid=b"",
+    )
+
+
+def test_info_appendix_c22_bytes():
+    info = _sample_info()
+    expected = bytes(
+        [
+            0x01,
+            0x00,
+            0x00,
+            0x01,
+            0x00,
+            0x02,
+            0x00,  # chip id
+            0x03,
+            0x00,
+            0x01,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,  # cap bitmap
+            0xE0,
+            0x1F,  # supported SF
+            0xFF,
+            0x03,  # supported BW
+            0xFF,
+            0x00,  # max payload 255
+            0x40,
+            0x00,  # rx q 64
+            0x10,
+            0x00,  # tx q 16
+            0x80,
+            0xD1,
+            0xF0,
+            0x08,  # freq min
+            0x00,
+            0x70,
+            0x38,
+            0x39,  # freq max
+            0xF7,
+            0x16,  # tx power min/max
+            0x08,  # mcu_uid_len
+            0xDE,
+            0xAD,
+            0xBE,
+            0xEF,
+            0x01,
+            0x23,
+            0x45,
+            0x67,
+            0x00,  # radio_uid_len
+        ],
+    )
+    assert info.encode() == expected
+    assert Info.decode(expected) == info
+
+
+def test_info_tolerates_trailing_bytes():
+    info = _sample_info()
+    wire = info.encode() + b"\xaa" * 10
+    assert Info.decode(wire) == info
+
+
+def test_info_supports():
+    info = _sample_info()
+    assert info.supports(Capability.LORA)
+    assert info.supports(Capability.LORA | Capability.FSK)
+    assert not info.supports(Capability.MULTI_CLIENT)
+    assert info.chip == RadioChipId.SX1262

tests/test_frame.py

@@ -0,0 +1,175 @@
+"""Frame codec tests — every Appendix C hex vector pinned.
+
+These match the Rust crate's ``tests/vectors.rs`` byte-for-byte. If the
+client-py and firmware ever disagree, one of these tests fails first.
+"""
+
+import pytest
+
+from donglora.commands import (
+    TYPE_PING,
+    TYPE_TX,
+    encode_ping_payload,
+    encode_tx_payload,
+)
+from donglora.events import TYPE_ERR, TYPE_OK, TYPE_TX_DONE
+from donglora.frame import (
+    Frame,
+    FrameCobsError,
+    FrameCrcError,
+    FrameTooShortError,
+    decode_frame,
+    encode_frame,
+    read_frame,
+)
+
+# ── §C.2.1 PING / OK ─────────────────────────────────────────────
+
+
+def test_c21_ping_encodes_to_spec_bytes():
+    wire = encode_frame(TYPE_PING, 0x0001, encode_ping_payload())
+    assert wire == bytes([0x03, 0x01, 0x01, 0x03, 0x9D, 0xC8, 0x00])
+
+
+def test_c21_ok_encodes_to_spec_bytes():
+    wire = encode_frame(TYPE_OK, 0x0001, b"")
+    assert wire == bytes([0x03, 0x80, 0x01, 0x03, 0xF7, 0xC4, 0x00])
+
+
+# ── §C.2.4 TX / OK / TX_DONE ─────────────────────────────────────
+
+
+def test_c24_tx_with_cad():
+    wire = encode_frame(TYPE_TX, 0x0004, encode_tx_payload(b"Hello", skip_cad=False))
+    assert wire == bytes(
+        [0x03, 0x04, 0x04, 0x01, 0x08, 0x48, 0x65, 0x6C, 0x6C, 0x6F, 0x26, 0x40, 0x00],
+    )
+
+
+def test_c24_ok():
+    wire = encode_frame(TYPE_OK, 0x0004, b"")
+    assert wire == bytes([0x03, 0x80, 0x04, 0x03, 0x02, 0x3B, 0x00])
+
+
+def test_c24_tx_done():
+    # Payload = result(0=TRANSMITTED) + airtime_us(30976 LE).
+    payload = bytes([0x00, 0x00, 0x79, 0x00, 0x00])
+    wire = encode_frame(TYPE_TX_DONE, 0x0004, payload)
+    assert wire == bytes(
+        [0x03, 0xC1, 0x04, 0x01, 0x01, 0x02, 0x79, 0x01, 0x03, 0xE3, 0xFA, 0x00],
+    )
+
+
+# ── §C.2.5 TX skip_cad ──────────────────────────────────────────
+
+
+def test_c25_tx_skip_cad():
+    wire = encode_frame(TYPE_TX, 0x0005, encode_tx_payload(b"URGENT", skip_cad=True))
+    assert wire == bytes(
+        [0x03, 0x04, 0x05, 0x0A, 0x01, 0x55, 0x52, 0x47, 0x45, 0x4E, 0x54, 0xDB, 0x1C, 0x00],
+    )
+
+
+# ── §C.5.1 ENOTCONFIGURED ───────────────────────────────────────
+
+
+def test_c51_err_notconfigured():
+    # Payload = 0x0003 LE.
+    wire = encode_frame(TYPE_ERR, 0x0028, bytes([0x03, 0x00]))
+    assert wire == bytes([0x03, 0x81, 0x28, 0x02, 0x03, 0x03, 0x53, 0x7E, 0x00])
+
+
+# ── §C.6.4 Async EFRAME (tag=0) ─────────────────────────────────
+
+
+def test_c64_async_err_eframe():
+    wire = encode_frame(TYPE_ERR, 0x0000, bytes([0x02, 0x01]))
+    assert wire == bytes([0x02, 0x81, 0x01, 0x05, 0x02, 0x01, 0xCE, 0xEF, 0x00])
+
+
+# ── §C.8.1 COBS edge: no zeros in body ─────────────────────────
+
+
+def test_c81_no_zeros_in_body():
+    # PING tag=0x0101 → tag bytes have no 0x00, body has no zeros.
+    wire = encode_frame(TYPE_PING, 0x0101, b"")
+    assert wire == bytes([0x06, 0x01, 0x01, 0x01, 0xBC, 0xD8, 0x00])
+
+
+# ── Decode-side round-trip ──────────────────────────────────────
+
+
+def test_decode_roundtrip_empty_payload():
+    wire = encode_frame(TYPE_PING, 0x0042, b"")
+    frame = decode_frame(wire[:-1])  # strip sentinel
+    assert frame == Frame(type_id=TYPE_PING, tag=0x0042, payload=b"")
+
+
+def test_decode_roundtrip_with_payload():
+    payload = b"hello-world"
+    wire = encode_frame(TYPE_TX, 0x0123, payload)
+    frame = decode_frame(wire[:-1])
+    assert frame.type_id == TYPE_TX
+    assert frame.tag == 0x0123
+    assert frame.payload == payload
+
+
+def test_decode_rejects_crc_flip():
+    wire = bytearray(encode_frame(TYPE_PING, 0x0001, b""))
+    # Flip one byte of the CRC region.
+    wire[-3] ^= 0x01
+    with pytest.raises((FrameCrcError, FrameCobsError)):
+        decode_frame(bytes(wire[:-1]))
+
+
+def test_decode_rejects_too_short_frame():
+    # COBS of a 4-byte body: [0x05, 0xAA, 0xBB, 0xCC, 0xDD]. Decodes to
+    # 4 bytes, under the 5-byte minimum (type + tag + crc).
+    wire = bytes([0x05, 0xAA, 0xBB, 0xCC, 0xDD])
+    with pytest.raises(FrameTooShortError):
+        decode_frame(wire)
+
+
+# ── read_frame with a BytesIO-like reader ──────────────────────
+
+
+class _FakeReader:
+    def __init__(self, data: bytes):
+        self._data = bytearray(data)
+
+    def read(self, n: int = 1) -> bytes:
+        if not self._data:
+            return b""
+        chunk = bytes(self._data[:n])
+        del self._data[:n]
+        return chunk
+
+
+def test_read_frame_yields_decoded_frame():
+    wire = encode_frame(TYPE_PING, 0x0001, b"")
+    r = _FakeReader(wire)
+    frame = read_frame(r)
+    assert frame == Frame(type_id=TYPE_PING, tag=0x0001, payload=b"")
+
+
+def test_read_frame_returns_none_on_timeout():
+    r = _FakeReader(b"")
+    assert read_frame(r) is None
+
+
+def test_read_frame_handles_back_to_back_frames():
+    a = encode_frame(TYPE_PING, 1, b"")
+    b = encode_frame(TYPE_PING, 2, b"")
+    r = _FakeReader(a + b)
+    assert read_frame(r).tag == 1
+    assert read_frame(r).tag == 2
+
+
+# ── Oversized payloads rejected ────────────────────────────────
+
+
+def test_encode_rejects_oversized_payload():
+    from donglora.frame import MAX_PAYLOAD_FIELD, FrameTooLargeError
+
+    with pytest.raises(FrameTooLargeError):
+        encode_frame(0xC0, 0x0000, b"\x42" * (MAX_PAYLOAD_FIELD + 1))

tests/test_modulation.py

@@ -0,0 +1,202 @@
+"""Per-modulation config encode/decode tests.
+
+The LoRa test pins the Appendix C.2.3 canonical EU868 byte sequence.
+The others round-trip through encode → decode.
+"""
+
+import pytest
+
+from donglora.modulation import (
+    FlrcBitrate,
+    FlrcBt,
+    FlrcCodingRate,
+    FlrcConfig,
+    FlrcPreambleLen,
+    FskConfig,
+    LoRaBandwidth,
+    LoRaCodingRate,
+    LoRaConfig,
+    LoRaHeaderMode,
+    LrFhssBandwidth,
+    LrFhssCodingRate,
+    LrFhssConfig,
+    LrFhssGrid,
+    decode_modulation,
+    encode_modulation,
+)
+
+# ── LoRa — spec bytes ───────────────────────────────────────────
+
+
+def test_lora_default_matches_appendix_c23():
+    cfg = LoRaConfig.default()
+    expected = bytes(
+        [
+            0xA0,
+            0x27,
+            0xBE,
+            0x33,  # freq_hz = 868_100_000
+            0x07,  # sf
+            0x07,  # bw = Khz125
+            0x00,  # cr = 4/5
+            0x08,
+            0x00,  # preamble_len = 8
+            0x24,
+            0x14,  # sync_word = 0x1424
+            0x0E,  # tx_power_dbm = 14
+            0x00,  # header explicit
+            0x01,  # payload_crc on
+            0x00,  # iq normal
+        ],
+    )
+    assert cfg.encode() == expected
+
+
+def test_lora_roundtrip():
+    cfg = LoRaConfig(
+        freq_hz=915_000_000,
+        sf=10,
+        bw=LoRaBandwidth.KHZ_250,
+        cr=LoRaCodingRate.CR_4_8,
+        preamble_len=32,
+        sync_word=0xABCD,
+        tx_power_dbm=22,
+        header_mode=LoRaHeaderMode.IMPLICIT,
+        payload_crc=False,
+        iq_invert=True,
+    )
+    assert LoRaConfig.decode(cfg.encode()) == cfg
+
+
+def test_lora_decode_rejects_wrong_length():
+    with pytest.raises(ValueError):
+        LoRaConfig.decode(b"\x00" * 14)
+
+
+def test_lora_decode_rejects_invalid_enum():
+    buf = bytearray(LoRaConfig.default().encode())
+    buf[5] = 99  # invalid bandwidth
+    with pytest.raises(ValueError):
+        LoRaConfig.decode(bytes(buf))
+
+
+# ── FSK ────────────────────────────────────────────────────────
+
+
+def test_fsk_roundtrip_with_sync_word():
+    cfg = FskConfig(
+        freq_hz=868_000_000,
+        bitrate_bps=50_000,
+        freq_dev_hz=25_000,
+        rx_bw=0x1A,
+        preamble_len=32,
+        sync_word=b"\x12\x34\x56\x78",
+    )
+    assert FskConfig.decode(cfg.encode()) == cfg
+
+
+def test_fsk_rejects_oversized_sync_word():
+    cfg = FskConfig(
+        freq_hz=0,
+        bitrate_bps=0,
+        freq_dev_hz=0,
+        rx_bw=0,
+        preamble_len=0,
+        sync_word=b"\x00" * 9,
+    )
+    with pytest.raises(ValueError):
+        cfg.encode()
+
+
+# ── LR-FHSS ────────────────────────────────────────────────────
+
+
+def test_lr_fhss_roundtrip():
+    cfg = LrFhssConfig(
+        freq_hz=915_000_000,
+        bw=LrFhssBandwidth.KHZ_137,
+        cr=LrFhssCodingRate.CR_2_3,
+        grid=LrFhssGrid.KHZ_25,
+        hopping=True,
+        tx_power_dbm=14,
+    )
+    assert LrFhssConfig.decode(cfg.encode()) == cfg
+
+
+def test_lr_fhss_rejects_nonzero_reserved():
+    cfg = LrFhssConfig(
+        freq_hz=0,
+        bw=LrFhssBandwidth.KHZ_39,
+        cr=LrFhssCodingRate.CR_1_3,
+        grid=LrFhssGrid.KHZ_25,
+        hopping=False,
+        tx_power_dbm=0,
+    )
+    buf = bytearray(cfg.encode())
+    buf[9] = 1
+    with pytest.raises(ValueError):
+        LrFhssConfig.decode(bytes(buf))
+
+
+# ── FLRC ───────────────────────────────────────────────────────
+
+
+def test_flrc_roundtrip():
+    cfg = FlrcConfig(
+        freq_hz=2_400_000_000,
+        bitrate=FlrcBitrate.KBPS_1300,
+        cr=FlrcCodingRate.CR_3_4,
+        bt=FlrcBt.BT_0_5,
+        preamble_len=FlrcPreambleLen.BITS_24,
+        sync_word=0x12345678,
+        tx_power_dbm=10,
+    )
+    assert FlrcConfig.decode(cfg.encode()) == cfg
+
+
+# ── Sum type (modulation_id prefix) ───────────────────────────
+
+
+def test_encode_modulation_prepends_lora_id():
+    cfg = LoRaConfig.default()
+    wire = encode_modulation(cfg)
+    assert wire[0] == 0x01
+    assert wire[1:] == cfg.encode()
+
+
+def test_decode_modulation_rejects_unknown_id():
+    with pytest.raises(ValueError):
+        decode_modulation(bytes([0x99]) + b"\x00" * 15)
+
+
+def test_decode_modulation_dispatches_correctly():
+    for cfg in (
+        LoRaConfig.default(),
+        FskConfig(
+            freq_hz=868_000_000,
+            bitrate_bps=9_600,
+            freq_dev_hz=5_000,
+            rx_bw=0,
+            preamble_len=16,
+            sync_word=b"\x12\x34",
+        ),
+        LrFhssConfig(
+            freq_hz=915_000_000,
+            bw=LrFhssBandwidth.KHZ_137,
+            cr=LrFhssCodingRate.CR_2_3,
+            grid=LrFhssGrid.KHZ_25,
+            hopping=True,
+            tx_power_dbm=14,
+        ),
+        FlrcConfig(
+            freq_hz=2_400_000_000,
+            bitrate=FlrcBitrate.KBPS_1300,
+            cr=FlrcCodingRate.CR_3_4,
+            bt=FlrcBt.BT_0_5,
+            preamble_len=FlrcPreambleLen.BITS_24,
+            sync_word=0x12345678,
+            tx_power_dbm=10,
+        ),
+    ):
+        wire = encode_modulation(cfg)
+        assert decode_modulation(wire) == cfg

tests/test_protocol.py

@@ -1,254 +0,0 @@
-"""Tests for donglora.protocol — ported from client-rs/src/protocol.rs tests."""
-
-from __future__ import annotations
-
-import struct
-
-import pytest
-
-from donglora.protocol import (
-    DEFAULT_CONFIG,
-    MAX_PAYLOAD,
-    PREAMBLE_DEFAULT,
-    RADIO_CONFIG_SIZE,
-    TX_POWER_MAX,
-    Bandwidth,
-    ErrorCode,
-    RadioConfig,
-    decode_config,
-    decode_response,
-    encode_command,
-    encode_config,
-)
-
-
-def _make_config() -> RadioConfig:
-    return {
-        "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 ──────────────────────────────────────────────────
-
-
-class TestRadioConfig:
-    def test_roundtrip(self) -> None:
-        cfg = _make_config()
-        encoded = encode_config(cfg)
-        assert len(encoded) == RADIO_CONFIG_SIZE
-        decoded = decode_config(encoded)
-        assert decoded == cfg
-
-    def test_default_roundtrip(self) -> None:
-        encoded = encode_config(DEFAULT_CONFIG)
-        decoded = decode_config(encoded)
-        assert decoded is not None
-        assert decoded["freq_hz"] == DEFAULT_CONFIG["freq_hz"]
-        assert decoded["bw"] == DEFAULT_CONFIG["bw"]
-        assert decoded["sf"] == DEFAULT_CONFIG["sf"]
-        assert decoded["cr"] == DEFAULT_CONFIG["cr"]
-        assert decoded["sync_word"] == DEFAULT_CONFIG["sync_word"]
-        assert decoded["tx_power_dbm"] == DEFAULT_CONFIG["tx_power_dbm"]
-        assert decoded["cad"] == DEFAULT_CONFIG["cad"]
-
-    def test_all_bandwidths(self) -> None:
-        for bw in Bandwidth:
-            cfg = {**_make_config(), "bw": bw}
-            encoded = encode_config(cfg)
-            decoded = decode_config(encoded)
-            assert decoded is not None
-            assert decoded["bw"] == bw
-
-    def test_invalid_bandwidth(self) -> None:
-        buf = bytearray(encode_config(_make_config()))
-        buf[4] = 255
-        assert decode_config(bytes(buf)) is None
-
-    def test_negative_power(self) -> None:
-        cfg = {**_make_config(), "tx_power_dbm": TX_POWER_MAX}
-        encoded = encode_config(cfg)
-        decoded = decode_config(encoded)
-        assert decoded is not None
-        assert decoded["tx_power_dbm"] == TX_POWER_MAX
-
-    def test_short_buffer(self) -> None:
-        assert decode_config(bytes(12)) is None
-        assert decode_config(b"") is None
-
-
-# ── Command encoding ─────────────────────────────────────────────
-
-
-class TestCommandEncoding:
-    def test_simple_tags(self) -> None:
-        assert encode_command("Ping") == bytes([0])
-        assert encode_command("GetConfig") == bytes([1])
-        assert encode_command("StartRx") == bytes([3])
-        assert encode_command("StopRx") == bytes([4])
-        assert encode_command("DisplayOn") == bytes([6])
-        assert encode_command("DisplayOff") == bytes([7])
-        assert encode_command("GetMac") == bytes([8])
-
-    def test_set_config(self) -> None:
-        cfg = _make_config()
-        cmd = encode_command("SetConfig", config=cfg)
-        assert cmd[0] == 2
-        assert len(cmd) == 1 + RADIO_CONFIG_SIZE
-        decoded = decode_config(cmd[1:])
-        assert decoded == cfg
-
-    def test_transmit_no_config(self) -> None:
-        cmd = encode_command("Transmit", payload=b"hello")
-        assert cmd[0] == 5
-        assert cmd[1] == 0  # has_config = false
-        length = struct.unpack_from("<H", cmd, 2)[0]
-        assert length == 5
-        assert cmd[4:] == b"hello"
-
-    def test_transmit_with_config(self) -> None:
-        cfg = _make_config()
-        cmd = encode_command("Transmit", config=cfg, payload=b"test")
-        assert cmd[0] == 5
-        assert cmd[1] == 1  # has_config = true
-        decoded = decode_config(cmd[2:])
-        assert decoded == cfg
-        offset = 2 + RADIO_CONFIG_SIZE
-        length = struct.unpack_from("<H", cmd, offset)[0]
-        assert length == 4
-        assert cmd[offset + 2 :] == b"test"
-
-    def test_transmit_empty_payload(self) -> None:
-        cmd = encode_command("Transmit", payload=b"")
-        assert cmd[0] == 5
-        length = struct.unpack_from("<H", cmd, 2)[0]
-        assert length == 0
-
-    def test_transmit_oversized_payload(self) -> None:
-        with pytest.raises(ValueError, match="payload too large"):
-            encode_command("Transmit", payload=bytes(MAX_PAYLOAD + 1))
-
-    def test_transmit_max_payload(self) -> None:
-        cmd = encode_command("Transmit", payload=bytes(MAX_PAYLOAD))
-        length = struct.unpack_from("<H", cmd, 2)[0]
-        assert length == MAX_PAYLOAD
-
-    def test_unknown_command(self) -> None:
-        with pytest.raises(ValueError, match="unknown command"):
-            encode_command("FakeCommand")
-
-
-# ── Response decoding ────────────────────────────────────────────
-
-
-class TestResponseDecoding:
-    def test_pong(self) -> None:
-        assert decode_response(bytes([0])) == {"type": "Pong"}
-
-    def test_config(self) -> None:
-        cfg = _make_config()
-        resp = decode_response(bytes([1]) + encode_config(cfg))
-        assert resp["type"] == "Config"
-        assert resp["freq_hz"] == cfg["freq_hz"]
-        assert resp["bw"] == cfg["bw"]
-        assert resp["sf"] == cfg["sf"]
-        assert resp["cr"] == cfg["cr"]
-        assert resp["sync_word"] == cfg["sync_word"]
-        assert resp["tx_power_dbm"] == cfg["tx_power_dbm"]
-        assert resp["preamble_len"] == cfg["preamble_len"]
-        assert resp["cad"] == cfg["cad"]
-
-    def test_rx_packet(self) -> None:
-        payload = b"data"
-        data = bytes([2])
-        data += struct.pack("<h", -80)
-        data += struct.pack("<h", 10)
-        data += struct.pack("<H", len(payload))
-        data += payload
-        resp = decode_response(data)
-        assert resp["type"] == "RxPacket"
-        assert resp["rssi"] == -80
-        assert resp["snr"] == 10
-        assert resp["payload"] == b"data"
-
-    def test_rx_packet_empty(self) -> None:
-        data = bytes([2])
-        data += struct.pack("<h", -120)
-        data += struct.pack("<h", -5)
-        data += struct.pack("<H", 0)
-        resp = decode_response(data)
-        assert resp["type"] == "RxPacket"
-        assert resp["payload"] == b""
-
-    def test_tx_done(self) -> None:
-        assert decode_response(bytes([3])) == {"type": "TxDone"}
-
-    def test_ok(self) -> None:
-        assert decode_response(bytes([4])) == {"type": "Ok"}
-
-    def test_error_codes(self) -> None:
-        for code in ErrorCode:
-            resp = decode_response(bytes([5, code]))
-            assert resp["type"] == "Error"
-            assert resp["code"] == code
-
-    def test_mac_address(self) -> None:
-        mac_bytes = bytes([0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF])
-        resp = decode_response(bytes([6]) + mac_bytes)
-        assert resp["type"] == "MacAddress"
-        assert resp["mac"] == "AA:BB:CC:DD:EE:FF"
-
-    def test_empty(self) -> None:
-        assert decode_response(b"") == {"type": "Empty"}
-
-    def test_unknown_tag(self) -> None:
-        resp = decode_response(bytes([255]))
-        assert resp["type"] == "Unknown(255)"
-
-
-# ── Cross-compatibility with firmware encoding ────────────────────
-
-
-class TestFirmwareCompatibility:
-    def test_worked_example(self) -> None:
-        """From PROTOCOL.md: 915 MHz, 125 kHz BW, SF7, CR 4/5, sync 0x1424, max power."""
-        cfg: RadioConfig = {
-            "freq_hz": 915_000_000,
-            "bw": Bandwidth.Khz125,
-            "sf": 7,
-            "cr": 5,
-            "sync_word": 0x1424,
-            "tx_power_dbm": TX_POWER_MAX,
-            "preamble_len": PREAMBLE_DEFAULT,
-            "cad": 1,
-        }
-        cmd = encode_command("SetConfig", config=cfg)
-        expected = bytes(
-            [0x02, 0xC0, 0xCA, 0x89, 0x36, 0x07, 0x07, 0x05, 0x24, 0x14, 0x80, 0x00, 0x00, 0x01]
-        )
-        assert cmd == expected
-
-
-# ── Enum coverage ────────────────────────────────────────────────
-
-
-class TestEnums:
-    def test_bandwidth_values(self) -> None:
-        assert Bandwidth.Khz7 == 0
-        assert Bandwidth.Khz500 == 9
-        assert len(Bandwidth) == 10
-
-    def test_error_code_values(self) -> None:
-        assert ErrorCode.InvalidConfig == 0
-        assert ErrorCode.RadioBusy == 1
-        assert ErrorCode.TxTimeout == 2
-        assert ErrorCode.CrcError == 3
-        assert ErrorCode.NotConfigured == 4
-        assert ErrorCode.NoDisplay == 5
-        assert len(ErrorCode) == 6

tests/test_session.py

@@ -0,0 +1,337 @@
+"""Session-level tests: tag correlation, async events, auto-recovery.
+
+Uses a `FakeTransport` — a thread-safe in-memory duplex pipe with a
+simple script of pre-canned firmware responses. Every test exercises
+the real frame codec; only the transport is faked.
+"""
+
+from __future__ import annotations
+
+import threading
+from collections.abc import Callable
+
+import pytest
+
+from donglora.commands import (
+    TYPE_GET_INFO,
+    TYPE_PING,
+    TYPE_RX_START,
+    TYPE_SET_CONFIG,
+    TYPE_TX,
+)
+from donglora.errors import (
+    BusyError,
+    Cancelled,
+    ChannelBusy,
+    NotConfiguredError,
+)
+from donglora.events import (
+    TYPE_ERR,
+    TYPE_OK,
+    TYPE_RX,
+    TYPE_TX_DONE,
+    Owner,
+    RxEvent,
+    RxOrigin,
+    SetConfigResult,
+    SetConfigResultCode,
+    TxDone,
+    TxResult,
+)
+from donglora.frame import decode_frame, encode_frame
+from donglora.info import Info, RadioChipId
+from donglora.modulation import LoRaConfig
+from donglora.session import Session
+
+# ── A tiny in-memory transport that simulates a device ─────────
+
+
+class FakeTransport:
+    """Thread-safe in-memory duplex pipe with a scripted device."""
+
+    def __init__(self, *, script: Callable[[int, int, bytes], list[bytes]] | None = None):
+        self._read_buf = bytearray()
+        self._read_cond = threading.Condition()
+        self._write_buf = bytearray()
+        self._write_cond = threading.Condition()
+        self._closed = False
+        self._script = script or _default_script
+        self._writer_thread = threading.Thread(
+            target=self._writer_loop,
+            name="fake-transport-writer",
+            daemon=True,
+        )
+        self._writer_thread.start()
+        self.log: list[bytes] = []
+
+    def write(self, data: bytes) -> int:
+        with self._write_cond:
+            self._write_buf.extend(data)
+            self._write_cond.notify_all()
+        return len(data)
+
+    def flush(self) -> None:
+        pass
+
+    def read(self, n: int = 1) -> bytes:
+        with self._read_cond:
+            while not self._read_buf and not self._closed:
+                self._read_cond.wait(timeout=0.1)
+                if self._closed:
+                    return b""
+            chunk = bytes(self._read_buf[:n])
+            del self._read_buf[:n]
+            return chunk
+
+    def close(self) -> None:
+        with self._read_cond:
+            self._closed = True
+            self._read_cond.notify_all()
+        with self._write_cond:
+            self._write_cond.notify_all()
+
+    def _writer_loop(self) -> None:
+        """Read framed commands off _write_buf, feed to the script,
+        push responses onto _read_buf.
+        """
+        while not self._closed:
+            with self._write_cond:
+                while not self._write_buf and not self._closed:
+                    self._write_cond.wait(timeout=0.1)
+                if self._closed:
+                    return
+                # Collect complete frames (ending in 0x00) from write_buf.
+                frames_raw: list[bytes] = []
+                while True:
+                    try:
+                        idx = self._write_buf.index(0)
+                    except ValueError:
+                        break
+                    frames_raw.append(bytes(self._write_buf[:idx]))
+                    del self._write_buf[: idx + 1]
+            for raw in frames_raw:
+                try:
+                    frame = decode_frame(raw)
+                except Exception:
+                    continue
+                self.log.append(raw)
+                responses = self._script(frame.type_id, frame.tag, frame.payload)
+                if responses:
+                    with self._read_cond:
+                        for r in responses:
+                            self._read_buf.extend(r)
+                        self._read_cond.notify_all()
+
+    # Kick an async event (e.g. RX) into the read stream.
+    def push_async(self, type_id: int, tag: int, payload: bytes) -> None:
+        wire = encode_frame(type_id, tag, payload)
+        with self._read_cond:
+            self._read_buf.extend(wire)
+            self._read_cond.notify_all()
+
+
+def _default_script(type_id: int, tag: int, payload: bytes) -> list[bytes]:  # noqa: ARG001
+    """Reasonable default: ACK every command with a shaped OK."""
+    if type_id == TYPE_PING:
+        return [encode_frame(TYPE_OK, tag, b"")]
+    if type_id == TYPE_GET_INFO:
+        info = _make_info()
+        return [encode_frame(TYPE_OK, tag, info.encode())]
+    if type_id == TYPE_SET_CONFIG:
+        result = SetConfigResult(
+            result=SetConfigResultCode.APPLIED,
+            owner=Owner.MINE,
+            current=LoRaConfig.default(),
+        )
+        return [encode_frame(TYPE_OK, tag, result.encode())]
+    if type_id == TYPE_RX_START:
+        return [encode_frame(TYPE_OK, tag, b"")]
+    if type_id == TYPE_TX:
+        td = TxDone(result=TxResult.TRANSMITTED, airtime_us=30_976)
+        return [
+            encode_frame(TYPE_OK, tag, b""),
+            encode_frame(TYPE_TX_DONE, tag, td.encode()),
+        ]
+    return [encode_frame(TYPE_OK, tag, b"")]
+
+
+def _make_info() -> Info:
+    return Info(
+        proto_major=1,
+        proto_minor=0,
+        fw_major=0,
+        fw_minor=1,
+        fw_patch=0,
+        radio_chip_id=RadioChipId.SX1262,
+        capability_bitmap=1 | (1 << 16),  # LoRa + CAD_BEFORE_TX
+        supported_sf_bitmap=0x1FE0,
+        supported_bw_bitmap=0x03FF,
+        max_payload_bytes=255,
+        rx_queue_capacity=32,
+        tx_queue_capacity=1,
+        freq_min_hz=150_000_000,
+        freq_max_hz=960_000_000,
+        tx_power_min_dbm=-9,
+        tx_power_max_dbm=22,
+        mcu_uid=b"\xde\xad\xbe\xef\x01\x23",
+        radio_uid=b"",
+    )
+
+
+# ── Session tests ──────────────────────────────────────────────
+
+
+@pytest.fixture
+def transport():
+    t = FakeTransport()
+    yield t
+    t.close()
+
+
+def test_session_ping(transport):
+    s = Session(transport)
+    try:
+        s.ping(timeout=2.0)
+    finally:
+        s.close()
+
+
+def test_session_get_info_returns_info_struct(transport):
+    s = Session(transport)
+    try:
+        info = s.get_info(timeout=2.0)
+        assert isinstance(info, Info)
+        assert info.proto_major == 1
+    finally:
+        s.close()
+
+
+def test_session_set_config_returns_set_config_result(transport):
+    s = Session(transport)
+    try:
+        result = s.set_config(LoRaConfig.default())
+        assert isinstance(result, SetConfigResult)
+        assert result.result == SetConfigResultCode.APPLIED
+    finally:
+        s.close()
+
+
+def test_session_transmit_returns_tx_done(transport):
+    s = Session(transport)
+    try:
+        td = s.transmit(b"Hello")
+        assert td.result == TxResult.TRANSMITTED
+        assert td.airtime_us == 30_976
+    finally:
+        s.close()
+
+
+def test_session_transmit_channel_busy(transport):
+    def script(type_id: int, tag: int, payload: bytes) -> list[bytes]:
+        if type_id == TYPE_TX:
+            td = TxDone(result=TxResult.CHANNEL_BUSY, airtime_us=0)
+            return [
+                encode_frame(TYPE_OK, tag, b""),
+                encode_frame(TYPE_TX_DONE, tag, td.encode()),
+            ]
+        return _default_script(type_id, tag, payload)
+
+    transport._script = script
+    s = Session(transport)
+    try:
+        with pytest.raises(ChannelBusy):
+            s.transmit(b"x")
+    finally:
+        s.close()
+
+
+def test_session_transmit_cancelled(transport):
+    def script(type_id: int, tag: int, payload: bytes) -> list[bytes]:
+        if type_id == TYPE_TX:
+            td = TxDone(result=TxResult.CANCELLED, airtime_us=0)
+            return [
+                encode_frame(TYPE_OK, tag, b""),
+                encode_frame(TYPE_TX_DONE, tag, td.encode()),
+            ]
+        return _default_script(type_id, tag, payload)
+
+    transport._script = script
+    s = Session(transport)
+    try:
+        with pytest.raises(Cancelled):
+            s.transmit(b"x")
+    finally:
+        s.close()
+
+
+def test_session_err_not_configured_raises(transport):
+    def script(type_id: int, tag: int, payload: bytes) -> list[bytes]:
+        if type_id == TYPE_TX:
+            return [encode_frame(TYPE_ERR, tag, b"\x03\x00")]
+        return _default_script(type_id, tag, payload)
+
+    transport._script = script
+    s = Session(transport)
+    try:
+        with pytest.raises(NotConfiguredError):
+            s.transmit(b"x")
+    finally:
+        s.close()
+
+
+def test_session_err_ebusy_raises(transport):
+    def script(type_id: int, tag: int, payload: bytes) -> list[bytes]:
+        if type_id == TYPE_TX:
+            return [encode_frame(TYPE_ERR, tag, b"\x06\x00")]
+        return _default_script(type_id, tag, payload)
+
+    transport._script = script
+    s = Session(transport)
+    try:
+        with pytest.raises(BusyError):
+            s.transmit(b"x")
+    finally:
+        s.close()
+
+
+def test_session_async_rx_event_arrives_on_queue(transport):
+    s = Session(transport)
+    try:
+        rx = RxEvent(
+            rssi_dbm=-73.5,
+            snr_db=9.5,
+            freq_err_hz=0,
+            timestamp_us=100,
+            crc_valid=True,
+            packets_dropped=0,
+            origin=RxOrigin.OTA,
+            data=b"\x01\x02\x03",
+        )
+        transport.push_async(TYPE_RX, 0, rx.encode())
+        delivered = s.next_rx(timeout=2.0)
+        assert delivered is not None
+        assert delivered.data == b"\x01\x02\x03"
+    finally:
+        s.close()
+
+
+def test_session_tag_correlation_across_concurrent_sends(transport):
+    # Two threads each send a PING. Both must resolve against their own tag.
+    s = Session(transport)
+    try:
+        errors: list[Exception] = []
+
+        def do_ping() -> None:
+            try:
+                s.ping(timeout=2.0)
+            except Exception as exc:
+                errors.append(exc)
+
+        threads = [threading.Thread(target=do_ping) for _ in range(10)]
+        for t in threads:
+            t.start()
+        for t in threads:
+            t.join(timeout=3.0)
+        assert errors == []
+    finally:
+        s.close()

uv.lock

@@ -296,7 +296,7 @@ wheels = [
 
 [[package]]
 name = "donglora"
-version = "0.2.0"
+version = "1.1.0"
 source = { editable = "." }
 dependencies = [
     { name = "cobs" },