Deep-analyze a single CAN message ID across all captured frames. Reports per-byte entropy, counter/checksum detection, and signal candidates.

Args: can_id: CAN message ID in decimal (e.g. 1234) or use int('0x4B0', 16).

Capture CAN frames for a fixed duration. Frames accumulate in the internal buffer for use by analysis tools.

Args: duration: Capture window in seconds. filter_ids: Optional list of decimal CAN IDs to capture. None = capture all.

Query OBD2 service 01 PID 00 to check if the vehicle supports OBD2 and which PIDs are available. Requires connection to the vehicle CAN bus (typically 500k or 250k baud on 11-bit ID bus).

Clear all captured frames from the internal buffer. Does not affect snapshots.

Diff two named snapshots to find which IDs and bytes changed.

Args: before_name: Label of the baseline snapshot. after_name: Label of the post-event snapshot.

Open a connection to a CAN interface.

Args: interface: Interface type ('pcan' for PEAK PCAN-USB, 'virtual' for testing). channel: Channel name (e.g. 'PCAN_USBBUS1'). baudrate: Bus speed in bps. Common: 500000, 250000, 1000000, 125000.

Decode a raw CAN frame against all known signal definitions for that CAN ID.

Args: can_id: CAN message ID. data_hex: Frame payload as a hex string, e.g. '0A1B2C3D4E5F6789'.

Define a named signal from a CAN message (bit-level precision). Physical value = (raw * scale) + offset.

Args: name: Signal name, e.g. 'engine_rpm' or 'throttle_pct'. can_id: CAN message ID. start_bit: LSB position (little_endian) or MSB position (big_endian), 0-based. length: Signal width in bits. byte_order: 'little_endian' (Intel/LSB-first) or 'big_endian' (Motorola/MSB-first). value_type: 'unsigned' or 'signed'. scale: Multiplier for raw→physical conversion. offset: Addend for raw→physical conversion. unit: Physical unit string, e.g. 'rpm', 'km/h', '%', '°C'. description: Human-readable description.

Auto-detect CAN bus baudrate by listening for valid frames at each common rate. Tries: 500k, 250k, 1M, 125k, 100k, 83.3k, 50k, 33.3k, 20k, 10k bps.

Requires live traffic on the bus. If the bus is idle, put the vehicle/ECU into a state that generates traffic (ignition on, engine running) before calling this.

Args: interface: CAN interface type. Use 'pcan' for PEAK PCAN-USB. channel: Interface channel. Default 'PCAN_USBBUS1' for first PCAN-USB device. timeout_per_rate: Seconds to listen at each baudrate before trying next.

Close the current CAN interface connection.

Export all current signal definitions to a DBC file. Can be opened in SavvyCAN, PEAK PCAN-Explorer, CANdb++, etc.

Args: file_path: Absolute path for the output .dbc file.

Summarize all captured message IDs: frame count, frequency, DLC, and category. High-frequency IDs (>100 Hz) are typically sensor loops. Low-frequency IDs (<5 Hz) are typically status or event-driven messages.

Import a DBC file and add its signal definitions to the current session. Signals are named as 'MessageName.SignalName'.

Args: file_path: Absolute path to the .dbc file.

List available CAN interface types, channels, and current connection status. Use this first to confirm what hardware/channels are available.

List all defined signals in the current session.

List all saved snapshots and their frame counts.

Send a raw OBD2 request and return the response bytes.

Args: service: OBD2 service number (e.g. 1 for current data, 3 for DTCs). pid: PID/subfunction number.

Query all known OBD2 PIDs (RPM, speed, throttle, temps, MAF, fuel level, etc.) and return decoded physical values.

Remove a signal definition by name.

Save the current capture buffer as a named snapshot.

Use this for before/after comparison:

1. Capture baseline traffic → take_snapshot('idle')

2. Trigger an action (press throttle, turn steering, etc.)

3. Capture again → take_snapshot('throttle_pressed')

4. compare_snapshots('idle', 'throttle_pressed') to find changed bytes

Args: name: Snapshot label.

Extract a byte range from captured frames and show how the value changes over time. Use this to observe a candidate signal while correlating with physical inputs.

Args: can_id: CAN message ID. start_byte: First byte index (0-based). num_bytes: How many consecutive bytes to read (1–4). signed: Interpret as signed integer. scale: Physical = raw * scale + offset. offset: Physical = raw * scale + offset. byte_order: 'little_endian' (Intel) or 'big_endian' (Motorola).