chore: release 1.1.0

CHANGELOG.md

@@ -1,5 +1,27 @@
 # 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

donglora/__init__.py

@@ -66,6 +66,7 @@ from donglora.errors import (
     BusyError,
     Cancelled,
     ChannelBusy,
+    ConfigNotSupported,
     DeviceError,
     DongloraError,
     ErrorCode,
@@ -131,6 +132,7 @@ __all__ = [
     "Cancelled",
     "Capability",
     "ChannelBusy",
+    "ConfigNotSupported",
     "DeviceError",
     "Dongle",
     "DongloraError",

donglora/connect.py

@@ -6,15 +6,21 @@ 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``.
+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()``.
+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
@@ -25,7 +31,7 @@ import serial
 
 from donglora.discovery import find_port, wait_for_device
 from donglora.dongle import Dongle
-from donglora.errors import DongloraError
+from donglora.errors import ConfigNotSupported, DongloraError
 from donglora.info import Info
 from donglora.modulation import LoRaConfig, Modulation
 from donglora.session import Session
@@ -131,6 +137,67 @@ def _open_transport(port: str | None, timeout: float) -> Any:
     return ser
 
 
+def _prepare_config(info: Info, config: Modulation) -> Modulation:
+    """Validate and auto-adjust *config* against the device's advertised caps.
+
+    Per-field policy:
+
+    * ``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.
+
+    Non-LoRa modulations pass through untouched — the firmware rejects
+    unsupported modulation IDs with ``EMODULATION`` on its own.
+    """
+    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,
     *,
@@ -158,9 +225,16 @@ def connect(
         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. The caller is then
-        responsible for calling :meth:`Dongle.set_config` before TX/RX.
+        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
@@ -195,12 +269,18 @@ def connect(
 
         applied: Modulation | None = None
         if auto_configure:
-            applied = config if config is not None else LoRaConfig.default()
+            requested: Modulation = config if config is not None else LoRaConfig.default()
             try:
-                session.set_config(applied, timeout=max(timeout, 2.0))
+                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()
@@ -315,10 +395,11 @@ def _session_on(transport: Any) -> Dongle:
         raise DongloraError(
             f"device speaks DongLoRa Protocol v{info.proto_major}.{info.proto_minor}; this client requires v1.x",
         )
-    applied = LoRaConfig.default()
     try:
-        session.set_config(applied)
+        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/dongle.py

@@ -99,7 +99,11 @@ class Dongle:
 
     @property
     def config(self) -> Modulation | None:
-        """The most-recently-applied radio config, or ``None`` if 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:

donglora/errors.py

@@ -42,6 +42,25 @@ 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."""
 

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "donglora"
-version = "1.0.1"
+version = "1.1.0"
 description = "DongLoRa host library — talk LoRa from Python over USB"
 license = "MIT"
 requires-python = ">=3.10"

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

uv.lock

@@ -296,7 +296,7 @@ wheels = [
 
 [[package]]
 name = "donglora"
-version = "1.0.0"
+version = "1.1.0"
 source = { editable = "." }
 dependencies = [
     { name = "cobs" },