can-bus-reverse-engineering-skills

Authoritative reference for the CSS Electronics CANsub product family (CANsub.2 and CANsub.4 CAN / CAN FD streaming interfaces). Use whenever a task needs accurate CANsub facts: hardware specs, the REST / WebSocket API, bit-timing, hardware filters, transmit sequences, connectors / pin-outs, firmware, certificate install; higher-layer protocols (OBD2, UDS, J1939, NMEA 2000, CANopen, CCP/XCP); the software tools (webCAN, SavvyCAN, PlotJuggler); or the python-can-cansub Python integration. Also consult it when another skill (e.g. cansub-reverse-engineering) needs CANsub context. Bundled doc snapshots live in assets/.

Reverse engineer / decode CAN bus signals: find which CAN ID, byte and bit encode a real-world quantity (vehicle speed, engine RPM, state-of-charge, coolant temp, throttle, door lock, ...) and derive its start-bit, length, endianness, scale and offset into a DBC. A deterministic chain of Python scripts (survey -> correlate -> bitsearch -> build_dbc -> verify) replaces "a human watches the screen to spot correlations". Works three ways: (1) OFFLINE - decode a signal from an EXISTING recorded log the user already has (a CAN + OBD2 log, an MF4/CANedge log, or a webCAN CSV) using a separately decodable reference such as an OBD2 PID (engine RPM, vehicle speed, coolant temp) or a CSS Electronics GPS source (CANmod.gps, or a CANedge's internal GPS/IMU on CAN9 - bundled DBCs, e.g. GPS speed as a reference for proprietary vehicle speed) - NO hardware needed; (2) LIVE - capture from a CSS Electronics CANsub interface with a human-supplied reference; or (3) VISION - the user has a CAN log plus a VIDEO of a display (dash

Combine multiple individual single-signal DBC files into one combined DBC at the application level. Use whenever the user wants to merge/combine/assemble several per-signal .dbc files (e.g. produced by the cansub-reverse-engineering skill under decoding-output/<application>/<signal>/<signal>.dbc) into a single application-wide DBC such as decoding-output/<application>/<application>.dbc. Re-runnable at any time as more signals are decoded. Triggers on phrasings like "combine the DBCs", "merge my signal DBCs", "build the combined/application DBC", "make one DBC from these".