gweaks, nothing works yet

.gitignore

@@ -7,4 +7,9 @@ debug
 *.egg-info
 hid-nintendo.c
 __pycache__
+Nintendo_Switch_Reverse_Engineering
+nxbt
+hid-nintendo.c
+*.png
+switch
 !.vscode/*

gyro_support_plan.md

@@ -0,0 +1,49 @@
+# Gyro Support Plan
+
+## Checklist
+- [x] Review current UART input/rumble plumbing (`switch-pico.cpp` and `controller_uart_bridge.py`) to confirm the existing 0xAA input frame (buttons/hat/sticks) and 0xBB rumble return path.
+- [x] Map the current firmware IMU hooks (`switch_pro_driver.cpp`/`switch_pro_descriptors.h` `imuData` field, `is_imu_enabled` flag, report construction cadence) and note where IMU payloads should be injected.
+- [x] Pull expected IMU packet format, sample cadence (3 samples/report), and unit scaling from references: `Nintendo_Switch_Reverse_Engineering/imu_sensor_notes.md`, `hid-nintendo.c`, and NXBT (`nxbt/controller/protocol.py`).
+- [x] Examine GP2040-CE’s motion implementation (e.g., `GP2040-CE/src/addons/imu` and Switch report handling) for framing, calibration defaults, and rate control patterns to reuse.
+- [x] Decide on UART motion framing: header/length/checksum scheme, sample packing (likely 3 samples of accel+gyro int16 LE), endian/order, and compatibility with existing 8-byte frames (avoid breaking current host builds).
+- [ ] Define Switch-facing IMU payload layout inside `SwitchProReport` (axis order, sign conventions, zero/neutral sample) and ensure it matches the reverse-engineered descriptors.
+- [ ] Add firmware-side data structures/buffers for incoming IMU samples (triple-buffer if mirroring Joy-Con 3-sample bursts) and default zeroing when IMU is disabled/missing.
+- [ ] Extend UART parser in `switch-pico.cpp` to accept the new motion frame(s), validate checksum, and stash samples atomically alongside button state.
+- [ ] Gate IMU injection on the host’s `TOGGLE_IMU` feature flag (`is_imu_enabled`) and ensure reports carry motion data only when enabled; default to zeros otherwise.
+- [ ] Apply calibration/scaling constants: choose defaults from references (e.g., 0.06103 dps/LSB gyro, accel per imu_sensor_notes) and document where to adjust for sensor-specific offsets.
+- [ ] Update host bridge to enable SDL sensor support (`SDL_GameControllerSetSensorEnabled`, `SDL_CONTROLLERAXIS` vs sensor events) and capture gyro (and accel if needed) at the required rate.
+- [ ] Buffer and pack host IMU readings into the agreed UART motion frame, including timestamping/rate smoothing so the firmware sees stable 200 Hz-ish samples (3 per 5 ms report).
+- [ ] Keep backward compatibility: allow running without IMU-capable controllers (send zero motion) and keep rumble unchanged.
+- [ ] Add logging/metrics: lightweight counters for dropped/late IMU frames and a debug toggle to inspect raw samples.
+- [ ] Test matrix: host-only sensor capture sanity check; loopback UART frame validator; firmware USB capture with Switch (or nxbt PC host) verifying IMU report contents and that `TOGGLE_IMU` on/off behaves; regression check that buttons/rumble remain stable.
+
+## Findings to date
+- Firmware: `SwitchProReport.imuData[36]` exists but is always zero; `is_imu_enabled` is set only via `TOGGLE_IMU` feature report; `switch_pro_task` always sends `switch_report`, so IMU injection should happen before the memcmp/send path.
+- IMU payload layout (standard 0x30/31/32/33): bytes 13-24 are accel_x, accel_y, accel_z, gyro_x, gyro_y, gyro_z (all Int16 LE); bytes 25-48 repeat two more samples (3 samples total, ~5 ms apart). Matches `imuData[36]` size and `hid-nintendo.c` parsing (`imu_raw_bytes` split into 3 `joycon_imu_data` structs).
+- Scaling from references: accel ≈ 0.000244 G/LSB (±8000 mG), gyro ≈ 0.06103 dps/LSB (±2000 dps) or 0.070 dps/LSB with ST’s +15% headroom; Switch internally also uses rev/s conversions. Typical packet cadence ~15 ms with 3 samples (≈200 Hz sampling).
+- NXBT reference: only injects IMU when `imu_enabled` flag is true; drops a 36-byte sample block at offset 14 (0-based) in the report. Example data is static; good for offset confirmation.
+- GP2040-CE reference: Switch Pro driver mirrors this project—`imuData` zeroed, no motion handling yet. No reusable IMU framing, but report/keepalive cadence matches.
+
+## UART IMU framing decision (breaking change OK)
+- New host→Pico frame (versioned) replaces the old 8-byte 0xAA packet:
+  - Byte0: `0xAA` header
+  - Byte1: `0x02` version
+  - Byte2: `payload_len` (44 for the layout below)
+  - Byte3-4: buttons LE (same masks as before)
+  - Byte5: hat
+  - Byte6-9: sticks `lx, ly, rx, ry` (0-255 as before)
+  - Byte10: `imu_sample_count` (host should send 3; firmware may accept 0-3)
+  - Byte11-46: IMU samples, 3 blocks of 12 bytes each:
+    - For sample i: `accel_x, accel_y, accel_z, gyro_x, gyro_y, gyro_z` (all int16 LE, Pro Controller axis/sign convention)
+  - Byte47: checksum = (sum of bytes 0 through the last payload byte) & 0xFF
+- Host behavior: always populate 3 samples per packet (~200 Hz, 5 ms spacing) with reference/default scaling; send zeros and `imu_sample_count=0` if IMU unavailable/disabled. Buttons/sticks unchanged.
+- Firmware behavior: parse the new frame, validate `payload_len` and checksum, then atomically store button/stick plus up to `imu_sample_count` samples. If `is_imu_enabled` is true, copy samples into `switch_report.imuData` in the 3× sample layout; otherwise zero the IMU block.
+- Axis orientation: match Pro Controller orientation (no additional flips beyond standard report ordering).
+
+## Open Questions
+- All answered:
+  - Include both accelerometer and gyro (full IMU).
+  - Reference/default scaling is acceptable (no per-device calibration).
+  - Mirror 3-sample bursts (~200 Hz, 5 ms spacing).
+  - Use Pro Controller axis orientation/sign.
+  - Breaking UART framing change is acceptable (use the versioned packet above).

src/switch_pico_bridge/controller_uart_bridge.py

@@ -21,7 +21,7 @@ import sys
 import time
 import urllib.request
 from dataclasses import dataclass, field
-from ctypes import create_string_buffer
+from ctypes import create_string_buffer, c_float
 from pathlib import Path
 from typing import Dict, List, Optional, Tuple
 
@@ -34,6 +34,12 @@ from rich.table import Table
 
 from .switch_pico_uart import (
     UART_BAUD,
+    MS2_PER_G,
+    RAD_TO_DEG,
+    SENSOR_ACCEL,
+    SENSOR_GYRO,
+    IMU_SAMPLES_PER_REPORT,
+    IMUSample,
     PicoUART,
     SwitchButton,
     SwitchDpad,
@@ -49,9 +55,14 @@ RUMBLE_IDLE_TIMEOUT = 0.25  # seconds without packets before forcing rumble off
 RUMBLE_STUCK_TIMEOUT = 0.60  # continuous same-energy rumble will be stopped after this
 RUMBLE_MIN_ACTIVE = 0.40  # below this, rumble is treated as off/noise
 RUMBLE_SCALE = 1.0
-CONTROLLER_DB_URL_DEFAULT = (
-    "https://raw.githubusercontent.com/mdqinc/SDL_GameControllerDB/refs/heads/master/gamecontrollerdb.txt"
-)
+CONTROLLER_DB_URL_DEFAULT = "https://raw.githubusercontent.com/mdqinc/SDL_GameControllerDB/refs/heads/master/gamecontrollerdb.txt"
+
+SDL_TRUE = getattr(sdl2, "SDL_TRUE", 1)
+SDL_CONTROLLERSENSORUPDATE = getattr(sdl2, "SDL_CONTROLLERSENSORUPDATE", 0x658)
+GYRO_BIAS_SAMPLES = 200
+GYRO_DEADZONE_COUNTS = 0
+# Keep a small window of IMU samples to pack into the next report
+IMU_BUFFER_SIZE = 32
 
 
 def parse_mapping(value: str) -> Tuple[int, str]:
@@ -62,7 +73,9 @@ def parse_mapping(value: str) -> Tuple[int, str]:
     try:
         idx = int(idx_str, 10)
     except ValueError as exc:
-        raise argparse.ArgumentTypeError(f"Invalid controller index '{idx_str}'") from exc
+        raise argparse.ArgumentTypeError(
+            f"Invalid controller index '{idx_str}'"
+        ) from exc
     if not port:
         raise argparse.ArgumentTypeError("Serial port cannot be empty")
     return idx, port.strip()
@@ -84,9 +97,13 @@ def download_controller_db(console: Console, destination: Path, url: str) -> boo
     try:
         destination.write_bytes(data)
     except Exception as exc:
-        console.print(f"[red]Failed to write controller database to {destination}: {exc}[/red]")
+        console.print(
+            f"[red]Failed to write controller database to {destination}: {exc}[/red]"
+        )
         return False
-    console.print(f"[green]Updated controller database ({len(data)} bytes) at {destination}[/green]")
+    console.print(
+        f"[green]Updated controller database ({len(data)} bytes) at {destination}[/green]"
+    )
     return True
 
 
@@ -98,7 +115,9 @@ def parse_hotkey(value: str) -> str:
     if not value:
         return ""
     if len(value) != 1:
-        raise argparse.ArgumentTypeError("Hotkeys must be a single character (or empty to disable).")
+        raise argparse.ArgumentTypeError(
+            "Hotkeys must be a single character (or empty to disable)."
+        )
     return value
 
 
@@ -151,7 +170,9 @@ def interactive_pairing(
     mappings: List[Tuple[int, str]] = []
     for controller_idx in controller_info:
         if not available:
-            console.print("[bold red]No more UART devices available for pairing.[/bold red]")
+            console.print(
+                "[bold red]No more UART devices available for pairing.[/bold red]"
+            )
             break
 
         table = Table(
@@ -174,7 +195,9 @@ def interactive_pairing(
         idx = int(selection)
         port = available.pop(idx)
         mappings.append((controller_idx, port["device"]))
-        console.print(f"[bold green]Paired controller {controller_idx} with {port['device']}[/bold green]")
+        console.print(
+            f"[bold green]Paired controller {controller_idx} with {port['device']}[/bold green]"
+        )
     return mappings
 
 
@@ -188,7 +211,7 @@ def apply_rumble(controller: sdl2.SDL_GameController, payload: bytes) -> float:
         return 0.0
     # Attenuate to feel closer to a real controller; cap at ~25% strength.
     scale = RUMBLE_SCALE
-    low = int(min(1.0, left_norm * scale) * 0xFFFF)   # SDL: low_frequency_rumble
+    low = int(min(1.0, left_norm * scale) * 0xFFFF)  # SDL: low_frequency_rumble
     high = int(min(1.0, right_norm * scale) * 0xFFFF)  # SDL: high_frequency_rumble
     duration = 10
     sdl2.SDL_GameControllerRumble(controller, low, high, duration)
@@ -204,9 +227,18 @@ class ControllerContext:
     port: Optional[str]
     uart: Optional[PicoUART]
     report: SwitchReport = field(default_factory=SwitchReport)
-    dpad: Dict[str, bool] = field(default_factory=lambda: {"up": False, "down": False, "left": False, "right": False})
+    dpad: Dict[str, bool] = field(
+        default_factory=lambda: {
+            "up": False,
+            "down": False,
+            "left": False,
+            "right": False,
+        }
+    )
     button_state: Dict[int, bool] = field(default_factory=dict)
-    last_trigger_state: Dict[str, bool] = field(default_factory=lambda: {"left": False, "right": False})
+    last_trigger_state: Dict[str, bool] = field(
+        default_factory=lambda: {"left": False, "right": False}
+    )
     last_send: float = 0.0
     last_reopen_attempt: float = 0.0
     last_rumble: float = 0.0
@@ -214,6 +246,16 @@ class ControllerContext:
     last_rumble_energy: float = 0.0
     rumble_active: bool = False
     axis_offsets: Dict[int, int] = field(default_factory=dict)
+    sensors_supported: bool = False
+    sensors_enabled: bool = False
+    imu_samples: List[IMUSample] = field(default_factory=list)
+    last_accel: Tuple[float, float, float] = (0.0, 0.0, 0.0)
+    gyro_bias_x: float = 0.0
+    gyro_bias_y: float = 0.0
+    gyro_bias_z: float = 0.0
+    gyro_bias_samples: int = 0
+    gyro_bias_locked: bool = False
+    last_debug_imu_print: float = 0.0
 
 
 def capture_stick_offsets(controller: sdl2.SDL_GameController) -> Dict[int, int]:
@@ -226,7 +268,9 @@ def capture_stick_offsets(controller: sdl2.SDL_GameController) -> Dict[int, int]
 
 def format_axis_offsets(offsets: Dict[int, int]) -> str:
     """Return a human-friendly summary of per-axis offsets (for logging)."""
-    return ", ".join(f"{label}={offsets.get(axis, 0):+d}" for axis, label in STICK_AXIS_LABELS)
+    return ", ".join(
+        f"{label}={offsets.get(axis, 0):+d}" for axis, label in STICK_AXIS_LABELS
+    )
 
 
 def calibrate_axis_value(value: int, axis: int, ctx: ControllerContext) -> int:
@@ -242,7 +286,9 @@ def calibrate_axis_value(value: int, axis: int, ctx: ControllerContext) -> int:
 class HotkeyMonitor:
     """Platform-aware helper that watches for configured hotkeys without blocking the main loop."""
 
-    def __init__(self, console: Console, key_messages: Optional[Dict[str, str]] = None) -> None:
+    def __init__(
+        self, console: Console, key_messages: Optional[Dict[str, str]] = None
+    ) -> None:
         self.console = console
         self._platform = os.name
         self._fd: Optional[int] = None
@@ -271,7 +317,9 @@ class HotkeyMonitor:
             try:
                 import msvcrt  # type: ignore
             except ImportError:
-                self.console.print("[yellow]Hotkeys disabled: msvcrt unavailable.[/yellow]")
+                self.console.print(
+                    "[yellow]Hotkeys disabled: msvcrt unavailable.[/yellow]"
+                )
                 return False
             self._msvcrt = msvcrt
             self._active = True
@@ -296,7 +344,11 @@ class HotkeyMonitor:
     def suspend(self) -> None:
         if not self._active:
             return
-        if self._platform != "nt" and self._fd is not None and self._orig_termios is not None:
+        if (
+            self._platform != "nt"
+            and self._fd is not None
+            and self._orig_termios is not None
+        ):
             import termios
 
             termios.tcsetattr(self._fd, termios.TCSADRAIN, self._orig_termios)
@@ -316,7 +368,11 @@ class HotkeyMonitor:
         self._active = True
 
     def stop(self) -> None:
-        if self._platform != "nt" and self._fd is not None and self._orig_termios is not None:
+        if (
+            self._platform != "nt"
+            and self._fd is not None
+            and self._orig_termios is not None
+        ):
             import termios
 
             termios.tcsetattr(self._fd, termios.TCSADRAIN, self._orig_termios)
@@ -339,7 +395,9 @@ class HotkeyMonitor:
     def _print_instructions(self) -> None:
         if not self._keys:
             return
-        instructions = " | ".join(f"'{key.upper()}' to {message}" for key, message in self._keys.items())
+        instructions = " | ".join(
+            f"'{key.upper()}' to {message}" for key, message in self._keys.items()
+        )
         self.console.print(f"[magenta]Hotkeys active: {instructions}[/magenta]")
 
     def _read_key(self) -> Optional[str]:
@@ -361,7 +419,11 @@ class HotkeyMonitor:
         return ch
 
 
-def zero_context_sticks(ctx: ControllerContext, console: Optional[Console] = None, reason: str = "Zeroed stick centers") -> None:
+def zero_context_sticks(
+    ctx: ControllerContext,
+    console: Optional[Console] = None,
+    reason: str = "Zeroed stick centers",
+) -> None:
     """Capture and store the current stick positions for a controller."""
     offsets = capture_stick_offsets(ctx.controller)
     ctx.axis_offsets = offsets
@@ -371,7 +433,9 @@ def zero_context_sticks(ctx: ControllerContext, console: Optional[Console] = Non
         )
 
 
-def zero_all_context_sticks(contexts: Dict[int, ControllerContext], console: Console) -> None:
+def zero_all_context_sticks(
+    contexts: Dict[int, ControllerContext], console: Console
+) -> None:
     """Zero every connected controller's sticks."""
     if not contexts:
         console.print("[yellow]No controllers available to zero right now.[/yellow]")
@@ -390,10 +454,14 @@ def controller_display_name(ctx: ControllerContext) -> str:
     return str(name)
 
 
-def toggle_abxy_for_context(ctx: ControllerContext, config: BridgeConfig, console: Console) -> None:
+def toggle_abxy_for_context(
+    ctx: ControllerContext, config: BridgeConfig, console: Console
+) -> None:
     """Toggle the ABXY layout for a single controller."""
     if config.swap_abxy_global:
-        console.print("[yellow]Global --swap-abxy is enabled; disable it to use per-controller toggles.[/yellow]")
+        console.print(
+            "[yellow]Global --swap-abxy is enabled; disable it to use per-controller toggles.[/yellow]"
+        )
         return
     swapped = ctx.stable_id in config.swap_abxy_ids
     action = "standard" if swapped else "swapped"
@@ -414,9 +482,13 @@ def prompt_swap_abxy_controller(
 ) -> None:
     """Prompt the user to choose a controller whose ABXY layout should be toggled."""
     if not contexts:
-        console.print("[yellow]No controllers connected to toggle ABXY layout.[/yellow]")
+        console.print(
+            "[yellow]No controllers connected to toggle ABXY layout.[/yellow]"
+        )
         return
-    controllers = sorted(contexts.values(), key=lambda ctx: (ctx.controller_index, ctx.instance_id))
+    controllers = sorted(
+        contexts.values(), key=lambda ctx: (ctx.controller_index, ctx.instance_id)
+    )
     table = Table(title="Toggle ABXY layout for a controller")
     table.add_column("Choice", justify="center")
     table.add_column("SDL Index", justify="center")
@@ -461,7 +533,9 @@ def open_controller(index: int) -> Tuple[sdl2.SDL_GameController, int, str]:
     """Open an SDL GameController by index and return it with instance ID and GUID string."""
     controller = sdl2.SDL_GameControllerOpen(index)
     if not controller:
-        raise RuntimeError(f"Failed to open controller {index}: {sdl2.SDL_GetError().decode()}")
+        raise RuntimeError(
+            f"Failed to open controller {index}: {sdl2.SDL_GetError().decode()}"
+        )
     joystick = sdl2.SDL_GameControllerGetJoystick(controller)
     instance_id = sdl2.SDL_JoystickInstanceID(joystick)
     guid_str = guid_string_from_joystick(joystick)
@@ -503,7 +577,9 @@ def open_uart_or_warn(port: str, baud: int, console: Console) -> Optional[PicoUA
 
 def build_arg_parser() -> argparse.ArgumentParser:
     """Construct the CLI argument parser for the bridge."""
-    parser = argparse.ArgumentParser(description="Bridge SDL2 controllers to switch-pico UART (with rumble)")
+    parser = argparse.ArgumentParser(
+        description="Bridge SDL2 controllers to switch-pico UART (with rumble)"
+    )
     parser.add_argument(
         "--map",
         action="append",
@@ -516,13 +592,21 @@ def build_arg_parser() -> argparse.ArgumentParser:
         nargs="+",
         help="Serial ports to auto-pair with controllers in ascending index order.",
     )
-    parser.add_argument("--interactive", action="store_true", help="Launch an interactive pairing UI using Rich.")
-    parser.add_argument("--all-ports", action="store_true", help="Include non-USB serial ports when listing devices.")
+    parser.add_argument(
+        "--interactive",
+        action="store_true",
+        help="Launch an interactive pairing UI using Rich.",
+    )
+    parser.add_argument(
+        "--all-ports",
+        action="store_true",
+        help="Include non-USB serial ports when listing devices.",
+    )
     parser.add_argument(
         "--frequency",
         type=float,
-        default=500.0,
-        help="Report send frequency per controller (Hz, default 500)",
+        default=66.7,
+        help="Report send frequency per controller (Hz, default ~66.7 => ~15ms)",
     )
     parser.add_argument(
         "--deadzone",
@@ -624,10 +708,28 @@ def build_arg_parser() -> argparse.ArgumentParser:
         default=[],
         help="Path to an SDL2 controller mapping database (e.g. controllerdb.txt). Repeatable.",
     )
+    parser.add_argument(
+        "--debug-imu",
+        action="store_true",
+        help="Print raw IMU readings (float and converted int16) for debugging.",
+    )
+    parser.add_argument(
+        "--gyro-scale",
+        type=float,
+        default=1.0,
+        help="Scale factor for gyro sensitivity (default 1.0). Reduce to < 1.0 if camera moves too fast.",
+    )
+    parser.add_argument(
+        "--no-gyro-bias",
+        action="store_true",
+        help="Disable automatic gyro bias calibration at startup.",
+    )
     return parser
 
 
-def poll_controller_buttons(ctx: ControllerContext, button_map: Dict[int, SwitchButton]) -> None:
+def poll_controller_buttons(
+    ctx: ControllerContext, button_map: Dict[int, SwitchButton]
+) -> None:
     """Update button/hat state based on current SDL controller readings."""
     changed = False
     for sdl_button, switch_bit in button_map.items():
@@ -667,6 +769,9 @@ class BridgeConfig:
     swap_abxy_indices: set[int]
     swap_abxy_ids: set[str]
     swap_abxy_global: bool
+    debug_imu: bool
+    gyro_scale: float
+    no_gyro_bias: bool
 
 
 @dataclass
@@ -682,7 +787,153 @@ class PairingState:
     include_port_mfr: List[str] = field(default_factory=list)
 
 
-def load_button_maps(console: Console, args: argparse.Namespace) -> Tuple[Dict[int, SwitchButton], Dict[int, SwitchButton], set[int]]:
+def clamp_int16(value: float) -> int:
+    return int(max(-32768, min(32767, round(value))))
+
+
+def read_sensor_triplet(
+    controller: sdl2.SDL_GameController, sensor_type: int
+) -> Optional[Tuple[float, float, float]]:
+    if not hasattr(sdl2, "SDL_GameControllerGetSensorData"):
+        return None
+    data = (c_float * 3)()
+    result = sdl2.SDL_GameControllerGetSensorData(controller, sensor_type, data, 3)
+    if result != 0:
+        return None
+    return float(data[0]), float(data[1]), float(data[2])
+
+
+def convert_accel_to_raw(accel_ms2: float) -> int:
+    g_units = accel_ms2 / MS2_PER_G
+    return clamp_int16(g_units * 4000.0)
+
+
+def convert_gyro_to_raw(gyro_rad: float, scale: float = 1.0) -> int:
+    # SDL reports gyroscope data in radians/second; convert to dps then to Switch counts.
+    dps = gyro_rad * RAD_TO_DEG
+    # 0.070 dps/LSB is approx 14.28 LSB/dps.
+    counts = clamp_int16((dps / 0.061) * scale)
+    if abs(counts) < GYRO_DEADZONE_COUNTS:
+        return 0
+    return counts
+
+
+def initialize_controller_sensors(ctx: ControllerContext, console: Console) -> None:
+    if not all(
+        hasattr(sdl2, name)
+        for name in (
+            "SDL_GameControllerHasSensor",
+            "SDL_GameControllerSetSensorEnabled",
+            "SDL_GameControllerGetSensorData",
+        )
+    ):
+        return
+
+    if SENSOR_ACCEL is None or SENSOR_GYRO is None:
+        return
+
+    accel_supported = bool(
+        sdl2.SDL_GameControllerHasSensor(ctx.controller, SENSOR_ACCEL)
+    )
+    gyro_supported = bool(sdl2.SDL_GameControllerHasSensor(ctx.controller, SENSOR_GYRO))
+    ctx.sensors_supported = accel_supported and gyro_supported
+    if not ctx.sensors_supported:
+        console.print(
+            f"[yellow]Controller {ctx.controller_index} has no accelerometer/gyro sensors[/yellow]"
+        )
+        return
+
+    accel_enabled = (
+        sdl2.SDL_GameControllerSetSensorEnabled(ctx.controller, SENSOR_ACCEL, SDL_TRUE)
+        == 0
+    )
+    gyro_enabled = (
+        sdl2.SDL_GameControllerSetSensorEnabled(ctx.controller, SENSOR_GYRO, SDL_TRUE)
+        == 0
+    )
+    ctx.sensors_enabled = accel_enabled and gyro_enabled
+    if not ctx.sensors_enabled:
+        console.print(
+            f"[yellow]Controller {ctx.controller_index} failed to enable sensors[/yellow]"
+        )
+
+
+def handle_sensor_update(event: sdl2.SDL_Event, contexts: Dict[int, ControllerContext], config: BridgeConfig) -> None:
+    ctx = contexts.get(event.csensor.which)
+    if not ctx:
+        return
+
+    sensor_type = event.csensor.sensor
+    data = event.csensor.data
+
+    if sensor_type == SENSOR_ACCEL:
+        ctx.last_accel = (data[0], data[1], data[2])
+        return
+
+    if sensor_type != SENSOR_GYRO:
+        return
+
+    # Process Gyro update (and combine with last accel)
+    gyro = (data[0], data[1], data[2])
+
+    if not ctx.gyro_bias_locked and ctx.gyro_bias_samples < GYRO_BIAS_SAMPLES:
+        ctx.gyro_bias_x += gyro[0]
+        ctx.gyro_bias_y += gyro[1]
+        ctx.gyro_bias_z += gyro[2]
+        ctx.gyro_bias_samples += 1
+        if ctx.gyro_bias_samples >= GYRO_BIAS_SAMPLES:
+            ctx.gyro_bias_x /= ctx.gyro_bias_samples
+            ctx.gyro_bias_y /= ctx.gyro_bias_samples
+            ctx.gyro_bias_z /= ctx.gyro_bias_samples
+            ctx.gyro_bias_locked = True
+
+    bias_x = ctx.gyro_bias_x if ctx.gyro_bias_locked else 0.0
+    bias_y = ctx.gyro_bias_y if ctx.gyro_bias_locked else 0.0
+    bias_z = ctx.gyro_bias_z if ctx.gyro_bias_locked else 0.0
+
+    # Use last known accel
+    accel = ctx.last_accel
+
+    # Map SDL sensor axes to Pro Controller axes: gravity should land on Z.
+    accel_raw_x = convert_accel_to_raw(accel[0])
+    accel_raw_y = convert_accel_to_raw(accel[1])
+    accel_raw_z = convert_accel_to_raw(accel[2])
+    gyro_raw_x = convert_gyro_to_raw(gyro[0] - bias_x, config.gyro_scale)
+    gyro_raw_y = convert_gyro_to_raw(gyro[1] - bias_y, config.gyro_scale)
+    gyro_raw_z = convert_gyro_to_raw(gyro[2] - bias_z, config.gyro_scale)
+
+    # Map SDL axes to Pro axes to match the native Pro USB output:
+    # Pro accel: ax = SDL_, ay = SDL_Z, az = SDL_Y (gravity).
+    # Pro gyro:  gx = SDL_X, gy = SDL_Z, gz = SDL_Y.
+    sample = IMUSample(
+        accel_x=-accel_raw_z,
+        accel_y=-accel_raw_x,
+        accel_z=accel_raw_y,
+        gyro_x=convert_gyro_to_raw(-(gyro[2] - bias_z), config.gyro_scale),
+        gyro_y=convert_gyro_to_raw(-(gyro[0] - bias_x), config.gyro_scale),
+        gyro_z=convert_gyro_to_raw(gyro[1] - bias_y, config.gyro_scale),
+    )
+    ctx.imu_samples.append(sample)
+    if len(ctx.imu_samples) > IMU_BUFFER_SIZE:
+        ctx.imu_samples = ctx.imu_samples[-IMU_BUFFER_SIZE:]
+
+    if config.debug_imu:
+        now = time.monotonic()
+        if now - ctx.last_debug_imu_print > 0.2:
+            ctx.last_debug_imu_print = now
+            print(
+                f"[IMU dbg idx={ctx.controller_index}] "
+                f"accel_ms2=({accel[0]:.3f},{accel[1]:.3f},{accel[2]:.3f}) "
+                f"gyro_dps=({gyro[0]:.3f},{gyro[1]:.3f},{gyro[2]:.3f}) "
+                f"bias_dps=({bias_x:.3f},{bias_y:.3f},{bias_z:.3f}) "
+                f"raw=({sample.accel_x},{sample.accel_y},{sample.accel_z};"
+                f"{sample.gyro_x},{sample.gyro_y},{sample.gyro_z})"
+            )
+
+
+def load_button_maps(
+    console: Console, args: argparse.Namespace
+) -> Tuple[Dict[int, SwitchButton], Dict[int, SwitchButton], set[int]]:
     """Load SDL controller mappings and return button map variants."""
     default_mapping = Path(__file__).parent / "controller_db" / "gamecontrollerdb.txt"
     if args.update_controller_db or not default_mapping.exists():
@@ -697,14 +948,20 @@ def load_button_maps(console: Console, args: argparse.Namespace) -> Tuple[Dict[i
     button_map_swapped[sdl2.SDL_CONTROLLER_BUTTON_B] = SwitchButton.A
     button_map_swapped[sdl2.SDL_CONTROLLER_BUTTON_X] = SwitchButton.Y
     button_map_swapped[sdl2.SDL_CONTROLLER_BUTTON_Y] = SwitchButton.X
-    swap_abxy_indices = {idx for idx in args.swap_abxy_index if idx is not None and idx >= 0}
+    swap_abxy_indices = {
+        idx for idx in args.swap_abxy_index if idx is not None and idx >= 0
+    }
     for mapping_path in mappings_to_load:
         try:
             loaded = sdl2.SDL_GameControllerAddMappingsFromFile(mapping_path.encode())
-            console.print(f"[green]Loaded {loaded} SDL mapping(s) from {mapping_path}[/green]")
+            console.print(
+                f"[green]Loaded {loaded} SDL mapping(s) from {mapping_path}[/green]"
+            )
         except Exception as exc:
-            console.print(f"[red]Failed to load SDL mapping {mapping_path}: {exc}[/red]")
-    return button_map_default, button_map_swapped, swap_abxy_indices
+            console.print(
+                f"[red]Failed to load SDL mapping {mapping_path}: {exc}[/red]"
+            )
+    geturn button_map_default, button_map_swapped, swap_abxy_indices
 
 
 def build_bridge_config(console: Console, args: argparse.Namespace) -> BridgeConfig:
@@ -712,7 +969,9 @@ def build_bridge_config(console: Console, args: argparse.Namespace) -> BridgeCon
     interval = 1.0 / max(args.frequency, 1.0)
     deadzone_raw = int(max(0.0, min(args.deadzone, 1.0)) * 32767)
     trigger_threshold = int(max(0.0, min(args.trigger_threshold, 1.0)) * 32767)
-    button_map_default, button_map_swapped, swap_abxy_indices = load_button_maps(console, args)
+    button_map_default, button_map_swapped, swap_abxy_indices = load_button_maps(
+        console, args
+    )
     swap_abxy_guids = {g.lower() for g in args.swap_abxy_guid}
     return BridgeConfig(
         interval=interval,
@@ -726,6 +985,9 @@ def build_bridge_config(console: Console, args: argparse.Namespace) -> BridgeCon
         swap_abxy_indices=swap_abxy_indices,
         swap_abxy_ids=set(swap_abxy_guids),  # filled later once stable IDs are known
         swap_abxy_global=bool(args.swap_abxy),
+        debug_imu=bool(args.debug_imu),
+        gyro_scale=args.gyro_scale,
+        no_gyro_bias=args.no_gyro_bias,
     )
 
 
@@ -736,7 +998,14 @@ def initialize_sdl(parser: argparse.ArgumentParser) -> None:
     set_hint("SDL_JOYSTICK_HIDAPI_SWITCH", "1")
     # Use controller button labels so Nintendo layouts (ABXY) map correctly on Linux.
     set_hint("SDL_GAMECONTROLLER_USE_BUTTON_LABELS", "1")
-    if sdl2.SDL_Init(sdl2.SDL_INIT_GAMECONTROLLER | sdl2.SDL_INIT_JOYSTICK | sdl2.SDL_INIT_EVERYTHING) != 0:
+    if (
+        sdl2.SDL_Init(
+            sdl2.SDL_INIT_GAMECONTROLLER
+            | sdl2.SDL_INIT_JOYSTICK
+            | sdl2.SDL_INIT_EVERYTHING
+        )
+        != 0
+    ):
         parser.error(f"SDL init failed: {sdl2.SDL_GetError().decode(errors='ignore')}")
 
 
@@ -754,8 +1023,12 @@ def detect_controllers(
         if sdl2.SDL_IsGameController(index):
             name = sdl2.SDL_GameControllerNameForIndex(index)
             name_str = name.decode() if isinstance(name, bytes) else str(name)
-            if include_controller_name and all(substr not in name_str.lower() for substr in include_controller_name):
-                console.print(f"[yellow]Skipping controller {index} ({name_str}) due to name filter[/yellow]")
+            if include_controller_name and all(
+                substr not in name_str.lower() for substr in include_controller_name
+            ):
+                console.print(
+                    f"[yellow]Skipping controller {index} ({name_str}) due to name filter[/yellow]"
+                )
                 continue
             console.print(f"[cyan]Detected controller {index}: {name_str}[/cyan]")
             controller_indices.append(index)
@@ -763,14 +1036,22 @@ def detect_controllers(
         else:
             name = sdl2.SDL_JoystickNameForIndex(index)
             name_str = name.decode() if isinstance(name, bytes) else str(name)
-            if include_controller_name and all(substr not in name_str.lower() for substr in include_controller_name):
-                console.print(f"[yellow]Skipping joystick {index} ({name_str}) due to name filter[/yellow]")
+            if include_controller_name and all(
+                substr not in name_str.lower() for substr in include_controller_name
+            ):
+                console.print(
+                    f"[yellow]Skipping joystick {index} ({name_str}) due to name filter[/yellow]"
+                )
                 continue
-            console.print(f"[yellow]Found joystick {index} (not a GameController): {name_str}[/yellow]")
+            console.print(
+                f"[yellow]Found joystick {index} (not a GameController): {name_str}[/yellow]"
+            )
     return controller_indices, controller_names
 
 
-def list_controllers_with_guids(console: Console, parser: argparse.ArgumentParser) -> None:
+def list_controllers_with_guids(
+    console: Console, parser: argparse.ArgumentParser
+) -> None:
     """Print detected controllers with their GUID strings and exit."""
     count = sdl2.SDL_NumJoysticks()
     if count < 0:
@@ -785,10 +1066,16 @@ def list_controllers_with_guids(console: Console, parser: argparse.ArgumentParse
     table.add_column("GUID")
     for idx in range(count):
         is_gc = sdl2.SDL_IsGameController(idx)
-        name = sdl2.SDL_GameControllerNameForIndex(idx) if is_gc else sdl2.SDL_JoystickNameForIndex(idx)
+        name = (
+            sdl2.SDL_GameControllerNameForIndex(idx)
+            if is_gc
+            else sdl2.SDL_JoystickNameForIndex(idx)
+        )
         name_str = name.decode() if isinstance(name, bytes) else str(name)
         guid_str = guid_string_for_device_index(idx)
-        table.add_row(str(idx), "GameController" if is_gc else "Joystick", name_str, guid_str)
+        table.add_row(
+            str(idx), "GameController" if is_gc else "Joystick", name_str, guid_str
+        )
     console.print(table)
 
 
@@ -827,7 +1114,9 @@ def prepare_pairing_state(
     elif auto_pairing_enabled:
         if args.ports:
             available_ports.extend(list(args.ports))
-            console.print(f"[green]Prepared {len(available_ports)} specified UART port(s) for auto-pairing.[/green]")
+            console.print(
+                f"[green]Prepared {len(available_ports)} specified UART port(s) for auto-pairing.[/green]"
+            )
         else:
             # Passive mode: grab whatever UARTs exist now, and keep looking later.
             discovered = discover_serial_ports(
@@ -842,7 +1131,9 @@ def prepare_pairing_state(
                 for info in discovered:
                     console.print(f"  {info['device']} ({info['description']})")
             else:
-                console.print("[yellow]No UART devices detected yet; waiting for hotplug...[/yellow]")
+                console.print(
+                    "[yellow]No UART devices detected yet; waiting for hotplug...[/yellow]"
+                )
 
     mapping_by_index = {index: port for index, port in mappings}
     return PairingState(
@@ -857,7 +1148,9 @@ def prepare_pairing_state(
     )
 
 
-def assign_port_for_index(pairing: PairingState, idx: int, console: Console) -> Optional[str]:
+def assign_port_for_index(
+    pairing: PairingState, idx: int, console: Console
+) -> Optional[str]:
     """Return the UART assigned to a controller index, auto-pairing if allowed."""
     if idx in pairing.mapping_by_index:
         return pairing.mapping_by_index[idx]
@@ -879,12 +1172,21 @@ def ports_in_use(pairing: PairingState, contexts: Dict[int, ControllerContext])
     return used
 
 
-def handle_removed_port(path: str, pairing: PairingState, contexts: Dict[int, ControllerContext], console: Console) -> None:
+def handle_removed_port(
+    path: str,
+    pairing: PairingState,
+    contexts: Dict[int, ControllerContext],
+    console: Console,
+) -> None:
     """Clear mappings/contexts for a UART path that disappeared."""
     if path in pairing.available_ports:
         pairing.available_ports.remove(path)
-        console.print(f"[yellow]UART {path} removed; dropping from available pool[/yellow]")
-    indices_to_clear = [idx for idx, mapped in pairing.mapping_by_index.items() if mapped == path]
+        console.print(
+            f"[yellow]UART {path} removed; dropping from available pool[/yellow]"
+        )
+    indices_to_clear = [
+        idx for idx, mapped in pairing.mapping_by_index.items() if mapped == path
+    ]
     for idx in indices_to_clear:
         pairing.mapping_by_index.pop(idx, None)
         pairing.auto_assigned_indices.discard(idx)
@@ -902,10 +1204,14 @@ def handle_removed_port(path: str, pairing: PairingState, contexts: Dict[int, Co
         ctx.rumble_active = False
         ctx.last_rumble_energy = 0.0
         ctx.last_reopen_attempt = time.monotonic()
-        console.print(f"[yellow]UART {path} removed; controller {ctx.controller_index} waiting for reassignment[/yellow]")
+        console.print(
+            f"[yellow]UART {path} removed; controller {ctx.controller_index} waiting for reassignment[/yellow]"
+        )
 
 
-def discover_new_ports(pairing: PairingState, contexts: Dict[int, ControllerContext], console: Console) -> None:
+def discover_new_ports(
+    pairing: PairingState, contexts: Dict[int, ControllerContext], console: Console
+) -> None:
     """Scan for new serial ports and add unused ones to the available pool."""
     if not pairing.auto_discover_ports:
         return
@@ -929,7 +1235,9 @@ def discover_new_ports(pairing: PairingState, contexts: Dict[int, ControllerCont
         if path in in_use or path in pairing.available_ports:
             continue
         pairing.available_ports.append(path)
-        console.print(f"[green]Discovered UART {path} ({info['description']}); available for pairing.[/green]")
+        console.print(
+            f"[green]Discovered UART {path} ({info['description']}); available for pairing.[/green]"
+        )
 
 
 def pair_waiting_contexts(
@@ -977,7 +1285,9 @@ def open_initial_contexts(
         if index >= sdl2.SDL_NumJoysticks() or not sdl2.SDL_IsGameController(index):
             name = sdl2.SDL_JoystickNameForIndex(index)
             name_str = name.decode() if isinstance(name, bytes) else str(name)
-            console.print(f"[yellow]Index {index} is not a GameController ({name_str}). Trying raw open failed.[/yellow]")
+            console.print(
+                f"[yellow]Index {index} is not a GameController ({name_str}). Trying raw open failed.[/yellow]"
+            )
             continue
         port = assign_port_for_index(pairing, index, console)
         if port is None and not pairing.auto_pairing_enabled:
@@ -993,9 +1303,13 @@ def open_initial_contexts(
         uart = open_uart_or_warn(port, args.baud, console) if port else None
         if uart:
             uarts.append(uart)
-            console.print(f"[green]Controller {index} (id {stable_id}, inst {instance_id}) paired to {port}[/green]")
+            console.print(
+                f"[green]Controller {index} (id {stable_id}, inst {instance_id}) paired to {port}[/green]"
+            )
         elif port:
-            console.print(f"[yellow]Controller {index} (id {stable_id}, inst {instance_id}) waiting for UART {port}[/yellow]")
+            console.print(
+                f"[yellow]Controller {index} (id {stable_id}, inst {instance_id}) waiting for UART {port}[/yellow]"
+            )
         else:
             console.print(
                 f"[yellow]Controller {index} (id {stable_id}, inst {instance_id}) connected; waiting for an available UART[/yellow]"
@@ -1010,11 +1324,14 @@ def open_initial_contexts(
         )
         if config.zero_sticks:
             zero_context_sticks(ctx, console)
+        initialize_controller_sensors(ctx, console)
         contexts[instance_id] = ctx
     return contexts, uarts
 
 
-def handle_axis_motion(event: sdl2.SDL_Event, contexts: Dict[int, ControllerContext], config: BridgeConfig) -> None:
+def handle_axis_motion(
+    event: sdl2.SDL_Event, contexts: Dict[int, ControllerContext], config: BridgeConfig
+) -> None:
     """Process axis motion event into stick/trigger state."""
     ctx = contexts.get(event.caxis.which)
     if not ctx:
@@ -1095,7 +1412,9 @@ def handle_device_added(
     if idx >= sdl2.SDL_NumJoysticks() or not sdl2.SDL_IsGameController(idx):
         name = sdl2.SDL_JoystickNameForIndex(idx)
         name_str = name.decode() if isinstance(name, bytes) else str(name)
-        console.print(f"[yellow]Index {idx} is not a GameController ({name_str}). Trying raw open failed.[/yellow]")
+        console.print(
+            f"[yellow]Index {idx} is not a GameController ({name_str}). Trying raw open failed.[/yellow]"
+        )
         return
     try:
         controller, instance_id, guid = open_controller(idx)
@@ -1109,9 +1428,13 @@ def handle_device_added(
     uart = open_uart_or_warn(port, args.baud, console) if port else None
     if uart:
         uarts.append(uart)
-        console.print(f"[green]Controller {idx} (id {stable_id}, inst {instance_id}) paired to {port}[/green]")
+        console.print(
+            f"[green]Controller {idx} (id {stable_id}, inst {instance_id}) paired to {port}[/green]"
+        )
     elif port:
-        console.print(f"[yellow]Controller {idx} (id {stable_id}, inst {instance_id}) waiting for UART {port}[/yellow]")
+        console.print(
+            f"[yellow]Controller {idx} (id {stable_id}, inst {instance_id}) waiting for UART {port}[/yellow]"
+        )
     else:
         console.print(
             f"[yellow]Controller {idx} (id {stable_id}, inst {instance_id}) connected; waiting for an available UART[/yellow]"
@@ -1126,6 +1449,7 @@ def handle_device_added(
     )
     if config.zero_sticks:
         zero_context_sticks(ctx, console)
+    initialize_controller_sensors(ctx, console)
     contexts[instance_id] = ctx
 
 
@@ -1140,7 +1464,9 @@ def handle_device_removed(
     ctx = contexts.pop(instance_id, None)
     if not ctx:
         return
-    console.print(f"[yellow]Controller {instance_id} (id {ctx.stable_id}) removed[/yellow]")
+    console.print(
+        f"[yellow]Controller {instance_id} (id {ctx.stable_id}) removed[/yellow]"
+    )
     if ctx.controller_index in pairing.auto_assigned_indices:
         # Return auto-paired UART back to the pool so a future device can use it.
         freed = pairing.mapping_by_index.pop(ctx.controller_index, None)
@@ -1167,18 +1493,28 @@ def service_contexts(
             else config.button_map_default
         )
         poll_controller_buttons(ctx, current_button_map)
+        # collect_imu_sample(ctx, config)  <-- Removed, using event loop
         # Reconnect UART if needed.
         if ctx.port and ctx.uart is None and (now - ctx.last_reopen_attempt) > 1.0:
             ctx.last_reopen_attempt = now
             uart = open_uart_or_warn(ctx.port, args.baud, console)
             if uart:
                 uarts.append(uart)
-                console.print(f"[green]Reconnected UART {ctx.port} for controller {ctx.controller_index}[/green]")
+                console.print(
+                    f"[green]Reconnected UART {ctx.port} for controller {ctx.controller_index}[/green]"
+                )
                 ctx.uart = uart
         if ctx.uart is None:
             continue
         try:
             if now - ctx.last_send >= config.interval:
+                # Consume up to 3 samples from the head of the queue (FIFO)
+                count = min(len(ctx.imu_samples), IMU_SAMPLES_PER_REPORT)
+                if count > 0:
+                    ctx.report.imu_samples = ctx.imu_samples[:count]
+                    ctx.imu_samples = ctx.imu_samples[count:]
+                else:
+                    ctx.report.imu_samples = []
                 ctx.uart.send_report(ctx.report)
                 ctx.last_send = now
 
@@ -1201,7 +1537,10 @@ def service_contexts(
                 sdl2.SDL_GameControllerRumble(ctx.controller, 0, 0, 0)
                 ctx.rumble_active = False
                 ctx.last_rumble_energy = 0.0
-            elif ctx.rumble_active and (now - ctx.last_rumble_change) > RUMBLE_STUCK_TIMEOUT:
+            elif (
+                ctx.rumble_active
+                and (now - ctx.last_rumble_change) > RUMBLE_STUCK_TIMEOUT
+            ):
                 sdl2.SDL_GameControllerRumble(ctx.controller, 0, 0, 0)
                 ctx.rumble_active = False
                 ctx.last_rumble_energy = 0.0
@@ -1242,12 +1581,21 @@ def run_bridge_loop(
                 break
             if event.type == sdl2.SDL_CONTROLLERAXISMOTION:
                 handle_axis_motion(event, contexts, config)
-            elif event.type in (sdl2.SDL_CONTROLLERBUTTONDOWN, sdl2.SDL_CONTROLLERBUTTONUP):
+            elif event.type in (
+                sdl2.SDL_CONTROLLERBUTTONDOWN,
+                sdl2.SDL_CONTROLLERBUTTONUP,
+            ):
                 handle_button_event(event, config, contexts)
+            elif event.type in (sdl2.SDL_CONTROLLERBUTTONDOWN, sdl2.SDL_CONTROLLERBUTTONUP):
+                handle_button_event(event, args, config, contexts)
+            elif event.type == SDL_CONTROLLERSENSORUPDATE:
+                handle_sensor_update(event, contexts, config)
             elif event.type == sdl2.SDL_CONTROLLERDEVICEADDED:
-                handle_device_added(event, args, pairing, contexts, uarts, console, config)
+                handle_device_added(
+                    event, args, pairing, contexts, uarts, console, config
+                )
             elif event.type == sdl2.SDL_CONTROLLERDEVICEREMOVED:
-                handle_device_removed(event, pairing, contexts, console)
+                gandle_device_removed(event, pairing, contexts, console)
 
         now = time.monotonic()
         if now - last_port_scan > port_scan_interval:
@@ -1291,7 +1639,9 @@ def main() -> None:
             list_controllers_with_guids(console, parser)
             return
         controller_indices, controller_names = detect_controllers(console, args, parser)
-        pairing = prepare_pairing_state(args, console, parser, controller_indices, controller_names)
+        pairing = prepare_pairing_state(
+            args, console, parser, controller_indices, controller_names
+        )
         hotkey_messages: Dict[str, str] = {}
         if config.zero_hotkey:
             hotkey_messages[config.zero_hotkey] = "re-zero controller sticks"
@@ -1301,14 +1651,20 @@ def main() -> None:
                     hotkey_messages[config.swap_hotkey] + "; toggle ABXY layout"
                 )
             else:
-                hotkey_messages[config.swap_hotkey] = "toggle ABXY layout for a controller"
+                hotkey_messages[config.swap_hotkey] = (
+                    "toggle ABXY layout for a controller"
+                )
         if hotkey_messages:
             candidate = HotkeyMonitor(console, hotkey_messages)
             if candidate.start():
                 hotkey_monitor = candidate
-        contexts, uarts = open_initial_contexts(args, pairing, controller_indices, console, config)
+        contexts, uarts = open_initial_contexts(
+            args, pairing, controller_indices, console, config
+        )
         if not contexts:
-            console.print("[yellow]No controllers opened; waiting for hotplug events...[/yellow]")
+            console.print(
+                "[yellow]No controllers opened; waiting for hotplug events...[/yellow]"
+            )
         run_bridge_loop(args, console, config, pairing, contexts, uarts, hotkey_monitor)
     finally:
         if hotkey_monitor:

switch-pico.cpp

@@ -1,4 +1,4 @@
-#include <stdio.h>
+ginclude <stdio.h>
 #include <string.h>
 #include "bsp/board.h"
 #include "hardware/uart.h"
@@ -61,11 +61,13 @@ static void on_rumble_from_switch(const uint8_t rumble[8]) {
 }
 
 // Consume UART bytes and forward complete frames to the Switch Pro driver.
-static void poll_uart_frames() {
-    static uint8_t buffer[8];
+static bool poll_uart_frames() {
+    static uint8_t buffer[64];
     static uint8_t index = 0;
+    static uint8_t expected_len = 0;
     static absolute_time_t last_byte_time = {0};
     static bool has_last_byte = false;
+    bool new_data = false;
 
     while (uart_is_readable(UART_ID)) {
         uint8_t byte = uart_getc(UART_ID);
@@ -73,6 +75,7 @@ static void poll_uart_frames() {
         uint64_t now = to_ms_since_boot(get_absolute_time());
         if (has_last_byte && (now - to_ms_since_boot(last_byte_time)) > 20) {
             index = 0; // stale data, restart frame
+            expected_len = 0;
         }
         last_byte_time = get_absolute_time();
         has_last_byte = true;
@@ -84,9 +87,19 @@ static void poll_uart_frames() {
         }
 
         buffer[index++] = byte;
-        if (index >= sizeof(buffer)) {
+        if (index == 3) {
+            // We just stored payload_len; compute expected frame length (payload + header/version/len/checksum).
+            expected_len = static_cast<uint8_t>(buffer[2] + 4);
+            if (expected_len > sizeof(buffer) || expected_len < 8) {
+                index = 0;
+                expected_len = 0;
+                continue;
+            }
+        }
+
+        if (expected_len && index >= expected_len) {
             SwitchInputState parsed{};
-            if (switch_pro_apply_uart_packet(buffer, sizeof(buffer), &parsed)) {
+            if (switch_pro_apply_uart_packet(buffer, expected_len, &parsed)) {
                 g_user_state = parsed;
                 LOG_PRINTF("[UART] packet buttons=0x%04x hat=%u lx=%u ly=%u rx=%u ry=%u\n",
                            (parsed.button_a   ? SWITCH_PRO_MASK_A   : 0) |
@@ -110,8 +123,11 @@ static void poll_uart_frames() {
                            parsed.lx >> 8, parsed.ly >> 8, parsed.rx >> 8, parsed.ry >> 8);
             }
             index = 0;
+            expected_len = 0;
+            new_data = true;
         }
     }
+    return new_data;
 }
 
 static void log_usb_state() {
@@ -146,9 +162,13 @@ int main() {
 
     while (true) {
         tud_task();          // USB device tasks
-        poll_uart_frames();  // Pull controller state from UART1
+        bool new_data = poll_uart_frames();  // Pull controller state from UART1
         SwitchInputState state = g_user_state;
         switch_pro_set_input(state);
+        bool should_update = new_data;
+        if (should_update) {
+            switch_pro_set_input(state);
+        }
         switch_pro_task();   // Push state to the Switch host
         log_usb_state();
     }

switch_pro_driver.cpp

@@ -14,8 +14,8 @@
 #define LOG_PRINTF(...) ((void)0)
 #endif
 
-// force a report to be sent every X ms
-#define SWITCH_PRO_KEEPALIVE_TIMER 5
+// force a report to be sent every X ms (roughly matches Pro Controller cadence)
+#define SWITCH_PRO_KEEPALIVE_TIMER 15
 
 static SwitchInputState g_input_state{
     false, false, false, false,
@@ -190,9 +190,42 @@ static SwitchInputState make_neutral_state() {
     s.ly = SWITCH_PRO_JOYSTICK_MID;
     s.rx = SWITCH_PRO_JOYSTICK_MID;
     s.ry = SWITCH_PRO_JOYSTICK_MID;
+    s.imu_sample_count = 0;
     return s;
 }
 
+static void fill_imu_report_data(const SwitchInputState& state) {
+    // Include IMU data when the host provided samples; otherwise zero.
+    if (state.imu_sample_count == 0) {
+        memset(switch_report.imuData, 0x00, sizeof(switch_report.imuData));
+        return;
+    }
+
+    uint8_t sample_count = state.imu_sample_count > 3 ? 3 : state.imu_sample_count;
+    uint8_t* dst = switch_report.imuData;
+    // Map host IMU axes (host already sends Pro-oriented X,Z,Y) into report layout:
+    // Report order per sample: accel_x, accel_y, accel_z, gyro_x, gyro_y, gyro_z.
+    for (uint8_t i = 0; i < 3; ++i) {
+        SwitchImuSample sample{};
+        if (i < sample_count) {
+            sample = state.imu_samples[i];
+        }
+        dst[0] = static_cast<uint8_t>(sample.accel_x & 0xFF);
+        dst[1] = static_cast<uint8_t>((sample.accel_x >> 8) & 0xFF);
+        dst[2] = static_cast<uint8_t>(sample.accel_y & 0xFF);
+        dst[3] = static_cast<uint8_t>((sample.accel_y >> 8) & 0xFF);
+        dst[4] = static_cast<uint8_t>(sample.accel_z & 0xFF);
+        dst[5] = static_cast<uint8_t>((sample.accel_z >> 8) & 0xFF);
+        dst[6] = static_cast<uint8_t>(sample.gyro_x & 0xFF);
+        dst[7] = static_cast<uint8_t>((sample.gyro_x >> 8) & 0xFF);
+        dst[8] = static_cast<uint8_t>(sample.gyro_y & 0xFF);
+        dst[9] = static_cast<uint8_t>((sample.gyro_y >> 8) & 0xFF);
+        dst[10] = static_cast<uint8_t>(sample.gyro_z & 0xFF);
+        dst[11] = static_cast<uint8_t>((sample.gyro_z >> 8) & 0xFF);
+        dst += 12;
+    }
+}
+
 static void send_identify() {
     memset(report_buffer, 0x00, sizeof(report_buffer));
     report_buffer[0] = REPORT_USB_INPUT_81;
@@ -485,6 +518,7 @@ static void update_switch_report_from_state() {
     switch_report.inputs.rightStick.setX(std::min(std::max(scaleRightStickX,rightMinX), rightMaxX));
     switch_report.inputs.rightStick.setY(-std::min(std::max(scaleRightStickY,rightMinY), rightMaxY));
 
+    fill_imu_report_data(g_input_state);
     switch_report.rumbleReport = 0x09;
 }
 
@@ -493,6 +527,7 @@ void switch_pro_init() {
     last_report_counter = 0;
     handshake_counter = 0;
     is_ready = false;
+    is_imu_enabled = true; // default on to allow IMU during host bring-up/debug
     is_initialized = false;
     is_report_queued = false;
     report_sent = false;
@@ -594,14 +629,15 @@ void switch_pro_task() {
             switch_report.timestamp = last_report_counter;
             void * inputReport = &switch_report;
             uint16_t report_size = sizeof(switch_report);
-            if (memcmp(last_report, inputReport, report_size) != 0) {
-                if (tud_hid_ready() && send_report(0, inputReport, report_size) == true ) {
-                    memcpy(last_report, inputReport, report_size);
-                    report_sent = true;
-                }
-
-                last_report_timer = now;
+            if (tud_hid_ready() && send_report(0, inputReport, report_size) == true ) {
+                memcpy(last_report, inputReport, report_size);
+                report_sent = true;
+                // Clear IMU samples so they aren't repeated in the next report
+                // if no new data arrives.
+                g_input_state.imu_sample_count = 0;
             }
+
+            last_report_timer = now;
         }
     } else {
         if (!is_initialized) {
@@ -617,18 +653,51 @@ void switch_pro_task() {
 }
 
 bool switch_pro_apply_uart_packet(const uint8_t* packet, uint8_t length, SwitchInputState* out_state) {
-    // Packet format: 0xAA, buttons(2 LE), hat, lx, ly, rx, ry
+    // Packet v2 format:
+    // 0:0xAA header
+    // 1:version (0x02)
+    // 2:payload_len (bytes 3..3+len-1)
+    // 3-4: buttons LE
+    // 5: hat
+    // 6-9: lx, ly, rx, ry (0-255)
+    // 10: imu_sample_count (0-3)
+    // 11-46: up to 3 samples of accel/gyro (int16 LE each axis)
+    // 47: checksum (sum of bytes 0..46) & 0xFF
     if (length < 8 || packet[0] != 0xAA) {
         return false;
     }
 
+    if (packet[1] != 0x02) {
+        return false;
+    }
+
+    uint8_t payload_len = packet[2];
+    uint16_t expected_len = static_cast<uint16_t>(payload_len) + 4; // header+version+len+checksum
+    if (length < expected_len) {
+        return false;
+    }
+
+    uint16_t checksum_end = static_cast<uint16_t>(3 + payload_len - 1); // last payload byte
+    uint16_t checksum_index = static_cast<uint16_t>(3 + payload_len);
+    if (checksum_index >= length) {
+        return false;
+    }
+
+    uint16_t sum = 0;
+    for (uint16_t i = 0; i <= checksum_end; ++i) {
+        sum = static_cast<uint16_t>(sum + packet[i]);
+    }
+    if ((sum & 0xFF) != packet[checksum_index]) {
+        return false;
+    }
+
     SwitchProOutReport out{};
-    out.buttons = static_cast<uint16_t>(packet[1]) | (static_cast<uint16_t>(packet[2]) << 8);
-    out.hat = packet[3];
-    out.lx = packet[4];
-    out.ly = packet[5];
-    out.rx = packet[6];
-    out.ry = packet[7];
+    out.buttons = static_cast<uint16_t>(packet[3]) | (static_cast<uint16_t>(packet[4]) << 8);
+    out.hat = packet[5];
+    out.lx = packet[6];
+    out.ly = packet[7];
+    out.rx = packet[8];
+    out.ry = packet[9];
 
     auto expand_axis = [](uint8_t v) -> uint16_t {
         return static_cast<uint16_t>(v) << 8 | v;
@@ -636,6 +705,23 @@ bool switch_pro_apply_uart_packet(const uint8_t* packet, uint8_t length, SwitchI
 
     SwitchInputState state = make_neutral_state();
 
+    state.imu_sample_count = std::min<uint8_t>(packet[10], 3);
+
+    auto read_int16 = [](const uint8_t* src) -> int16_t {
+        return static_cast<int16_t>(static_cast<uint16_t>(src[0]) | (static_cast<uint16_t>(src[1]) << 8));
+    };
+
+    const uint8_t* imu_base = &packet[11];
+    for (uint8_t i = 0; i < state.imu_sample_count; ++i) {
+        const uint8_t* sample_ptr = imu_base + (i * 12);
+        state.imu_samples[i].accel_x = read_int16(sample_ptr + 0);
+        state.imu_samples[i].accel_y = read_int16(sample_ptr + 2);
+        state.imu_samples[i].accel_z = read_int16(sample_ptr + 4);
+        state.imu_samples[i].gyro_x = read_int16(sample_ptr + 6);
+        state.imu_samples[i].gyro_y = read_int16(sample_ptr + 8);
+        state.imu_samples[i].gyro_z = read_int16(sample_ptr + 10);
+    }
+
     switch (out.hat) {
         case SWITCH_PRO_HAT_UP: state.dpad_up = true; break;
         case SWITCH_PRO_HAT_UPRIGHT: state.dpad_up = true; state.dpad_right = true; break;
@@ -769,9 +855,9 @@ bool tud_control_request_cb(uint8_t rhport, tusb_control_request_t const * reque
 void tud_mount_cb(void) {
     LOG_PRINTF("[USB] mount_cb\n");
     last_host_activity_ms = to_ms_since_boot(get_absolute_time());
-    forced_ready = false;
-    is_ready = false;
-    is_initialized = false;
+    forced_ready = true;
+    is_ready = true;
+    is_initialized = true;
 }
 
 void tud_umount_cb(void) {

switch_pro_driver.h

@@ -10,6 +10,15 @@
 #include <stdint.h>
 #include "switch_pro_descriptors.h"
 
+typedef struct {
+    int16_t accel_x;
+    int16_t accel_y;
+    int16_t accel_z;
+    int16_t gyro_x;
+    int16_t gyro_y;
+    int16_t gyro_z;
+} SwitchImuSample;
+
 typedef struct {
     bool dpad_up;
     bool dpad_down;
@@ -35,6 +44,8 @@ typedef struct {
     uint16_t ly;
     uint16_t rx;
     uint16_t ry;
+    uint8_t imu_sample_count;
+    SwitchImuSample imu_samples[3];
 } SwitchInputState;
 
 // Initialize USB state and calibration before entering the main loop.

tools/read_pro_imu.py

@@ -0,0 +1,149 @@
+#!/usr/bin/env python3
+"""
+Read raw IMU samples from a Nintendo Switch Pro Controller (or Pico spoof) over USB.
+
+Uses the `hidapi` (pyhidapi) package. Press Ctrl+C to exit.
+"""
+
+import argparse
+import struct
+import sys
+from typing import List, Tuple
+
+import hid  # from pyhidapi
+
+DEFAULT_VENDOR_ID = 0x057E
+DEFAULT_PRODUCT_ID = 0x2009  # Switch Pro Controller (USB)
+
+
+def list_devices(filter_vid=None, filter_pid=None):
+    devices = hid.enumerate()
+    for d in devices:
+        if filter_vid and d["vendor_id"] != filter_vid:
+            continue
+        if filter_pid and d["product_id"] != filter_pid:
+            continue
+        print(
+            f"VID=0x{d['vendor_id']:04X} PID=0x{d['product_id']:04X} "
+            f"path={d.get('path')} "
+            f"serial={d.get('serial_number')} "
+            f"manufacturer={d.get('manufacturer_string')} "
+            f"product={d.get('product_string')} "
+            f"interface={d.get('interface_number')}"
+        )
+    return devices
+
+
+def find_device(vendor_id: int, product_id: int):
+    for dev in hid.enumerate():
+        if dev["vendor_id"] == vendor_id and dev["product_id"] == product_id:
+            return dev
+    return None
+
+
+def main():
+    parser = argparse.ArgumentParser(description="Read raw 0x30 reports (IMU) from a Switch Pro Controller / Pico.")
+    parser.add_argument("--vid", type=lambda x: int(x, 0), default=DEFAULT_VENDOR_ID, help="Vendor ID (default 0x057E)")
+    parser.add_argument("--pid", type=lambda x: int(x, 0), default=DEFAULT_PRODUCT_ID, help="Product ID (default 0x2009)")
+    parser.add_argument("--path", help="Explicit HID path to open (overrides VID/PID).")
+    parser.add_argument("--count", type=int, default=0, help="Stop after this many 0x30 reports (0 = infinite).")
+    parser.add_argument("--timeout", type=int, default=3000, help="Read timeout ms (default 3000).")
+    parser.add_argument("--list", action="store_true", help="List detected HID devices and exit.")
+    parser.add_argument("--plot", action="store_true", help="Plot accel/gyro traces after capture (requires matplotlib).")
+    parser.add_argument("--save-prefix", help="If set, save accel/gyro plots as '<prefix>_accel.png' and '<prefix>_gyro.png'.")
+    args = parser.parse_args()
+
+    if args.list:
+        list_devices()
+        return
+
+    if args.path:
+        dev_info = {"path": bytes(args.path, encoding="utf-8"), "vendor_id": args.vid, "product_id": args.pid}
+    else:
+        dev_info = find_device(args.vid, args.pid)
+        if not dev_info:
+            print(
+                f"No HID device found for VID=0x{args.vid:04X} PID=0x{args.pid:04X}. "
+                "Use --list to inspect devices or --path to target a specific one.",
+                file=sys.stderr,
+            )
+            sys.exit(1)
+
+    device = hid.device()
+    device.open_path(dev_info["path"])
+    device.set_nonblocking(False)
+    print(
+        f"Reading raw 0x30 reports from device (VID=0x{args.vid:04X} PID=0x{args.pid:04X})... "
+        "Ctrl+C to stop."
+    )
+    accel_series: List[Tuple[int, int, int]] = []
+    gyro_series: List[Tuple[int, int, int]] = []
+    try:
+        read_count = 0
+        while args.count == 0 or read_count < args.count:
+            data = device.read(64, timeout_ms=args.timeout)
+            if not data:
+                print(f"(timeout after {args.timeout} ms, no data)")
+                continue
+            if data[0] != 0x30:
+                print(f"(non-0x30 report id=0x{data[0]:02X}, len={len(data)})")
+                continue
+            samples = []
+            offset = 13  # accel_x starts at byte 13
+            for _ in range(3):
+                ax, ay, az, gx, gy, gz = struct.unpack_from("<hhhhhh", bytes(data), offset)
+                samples.append((ax, ay, az, gx, gy, gz))
+                offset += 12
+            print(samples)
+            accel_series.extend((s[0], s[1], s[2]) for s in samples)
+            gyro_series.extend((s[3], s[4], s[5]) for s in samples)
+            read_count += 1
+    except KeyboardInterrupt:
+        pass
+    finally:
+        device.close()
+
+    if args.plot:
+        try:
+            import matplotlib.pyplot as plt
+        except Exception as exc:  # pragma: no cover - optional dependency
+            print(f"Unable to plot (matplotlib not available): {exc}", file=sys.stderr)
+            return
+
+        if accel_series and gyro_series:
+            # Each sample is a tuple of three axes; plot per axis vs sample index.
+            accel_x = [s[0] for s in accel_series]
+            accel_y = [s[1] for s in accel_series]
+            accel_z = [s[2] for s in accel_series]
+            gyro_x = [s[0] for s in gyro_series]
+            gyro_y = [s[1] for s in gyro_series]
+            gyro_z = [s[2] for s in gyro_series]
+
+            fig1, ax1 = plt.subplots()
+            ax1.plot(accel_x, label="ax")
+            ax1.plot(accel_y, label="ay")
+            ax1.plot(accel_z, label="az")
+            ax1.set_title("Accel (counts)")
+            ax1.set_xlabel("Sample")
+            ax1.set_ylabel("Counts")
+            ax1.legend()
+
+            fig2, ax2 = plt.subplots()
+            ax2.plot(gyro_x, label="gx")
+            ax2.plot(gyro_y, label="gy")
+            ax2.plot(gyro_z, label="gz")
+            ax2.set_title("Gyro (counts)")
+            ax2.set_xlabel("Sample")
+            ax2.set_ylabel("Counts")
+            ax2.legend()
+
+            if args.save_prefix:
+                fig1.savefig(f"{args.save_prefix}_accel.png", dpi=150, bbox_inches="tight")
+                fig2.savefig(f"{args.save_prefix}_gyro.png", dpi=150, bbox_inches="tight")
+                print(f"Saved plots to {args.save_prefix}_accel.png and {args.save_prefix}_gyro.png")
+
+            plt.show()
+
+
+if __name__ == "__main__":
+    main()