CAN bus sniffer and SAE J1939 protocol analyzer. Reads CAN frames (candump format or native SocketCAN), decodes them via a J1939 Digital Annex (xlsx/csv), and shows the result in an interactive TUI or as JSON.
- TUI — interactive terminal UI; per-CAN-ID modes:
brief,verbose,charts,manual - Live charts — per-SPN scatter plot with auto-scaled Y axis
- Manual / reverse-engineering — build custom SPNs over a live CAN ID by picking byte/bit ranges
- Regex filter — over CAN ID / PGN label
- Headless — stream decoded values as NDJSON to stdout
- Discover — one pass over the bus, dump a JSON tree of all PGNs/SPNs
- Record — capture every frame to SQLite (delta-encoded, rotating)
- Playback — replay received frames or your own config
Requires clang++ (C++20), CMake ≥ 3.13, Ninja, and system libs: boost, sqlite3, zlib, icu. Other deps are fetched automatically.
make build # native (dynamic). Also: build_static, build_arm64, install
make list # all targetsBinary: build/native/canscope. See make list for static / arm64 / Docker targets.
Modes are mutually exclusive; default is TUI.
# TUI
canscope -e "candump can0" -j1939-csv thirdparty/j1939da_2018.csv
# Native SocketCAN (Linux), or read from stdin
canscope -can can0 -j1939-csv thirdparty/j1939da_2018.csv
candump can0 | canscope -j1939-csv thirdparty/j1939da_2018.csv| Mode | Flag | Description |
|---|---|---|
| TUI | (default) | Interactive full-screen UI |
| Discover | -discover |
Dump PGN/SPN structure to stdout or -of <file> |
| Headless | -hl |
Stream decoded values as NDJSON |
| Record | -rec -db <file> |
Write decoded values + timestamps to SQLite |
Source: -e <cmd> (e.g. "candump can0"), -can <list> (native, e.g. can0,can1 or any), or stdin. J1939 DA: -j1939-csv (faster) or -j1939-xlsx. Run canscope -h for all flags.
Tested with the J1939 Digital Annex 2018 edition.
NMEA 2000 and CANopen decoding, plus assorted UI/perf improvements.