21cacf8c54
Some explanations of CAN byte order and bit numbering: openxcplatform-bitnumbering Mathworks-Side CAN frame data is either in big endian or little endian byte format. The bits are numbered by the file format either using MSB first (MSB0) or LSB first (LSB0). With "consistent" format/numbering, bit numbering follows the byte format. MSB0 for big endian, LSB0 for little endian. ietf-endianess Usually the start bit referenced by the file formats reference the start of the signal data within the message independent of the endianess of the signal. With some formats (DBF), the startbit may always reference the LSB of the signal data. Common formats: KCD, SYM (consistent bit numbering) little,LSB0 big,MSB0 DBC, ARXML (OSEK bit numbering) little,LSB0 big,LSB0 (inconsistent) DBF (startBit=LSB, startByte and startBit specified separately) little,LSB0 big,LSB0,startBit=LSB (inconsistent) Legacy canmatrix (yaml, json) (Note: internally canmatrix now uses consistent bit numbering) little,LSB0 big,LSB0,startBit=LSB (inconsistent) ###First Example: Frame with two 32-bit signals in motorola one can-frame 7 6 5 4 3 2 1 0 0>msb----- 1 signal1 2 3 ----lsb> 4>msb----- 5 signal2 6 7 ----lsb> DBC: BO_ 291 newFrameMotorola: 8 Vector__XXX SG_ signal1 : 7|32@0- (1,0) [0|0] "" Vector__XXX (most significant bit) SG_ signal2 : 39|32@0- (1,0) [0|0] "" Vector__XXX (most significant bit) candb++ views: signal1: 24 (least significant bit?) signal2: 56 (least significant bit?) Dbf: byte 4 bit 0 byte 8 bit 0 ###Second Example: 7 6 5 4 3 2 1 0 0 >msb--- 1---------lsb> 2 3 4 5 6 7 DBC: startbit 3 length 11 candb++ views: Startbit 9 (least significant bit?) dbf: length 11 byte 2 (counting starts with byte 1) bit 1 ##found docs about kcd "Least significant bit offset of the signal relative to the least significant bit of the messages data payload." least significant bit? estimation about dbf least significant bit? new formulars from dmahurin Note the basic operations used. convert from lsb0 bit numbering to msb0 bit numbering (or msb0 to lsb0) b = b - (b % 8) + 7 - (b % 8) convert from lsbit of signal data to msbit of signal data, when bit numbering is msb0 b = b + 1 - length convert from msbit of signal data to lsbit of signal data, when bit numbering is msb0 b = b + length - 1 So conversion from msbit in lsb0 bit numbering to msbit in lsb0 bit numbering is: b = b - (b % 8) + 7 - (b % 8) b = b + length - 1 b = b - (b % 8) + 7 - (b % 8) byte order names little endian == Intel == MOST-SIGNIFICANT-BYTE-LAST big endian == Motorola == MOST-SIGNIFICANT-BYTE-FIRST |
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| .github/workflows | ||
| .run | ||
| ext | ||
| gradle/wrapper | ||
| opendbc@098ba88138 | ||
| output | ||
| playback | ||
| random | ||
| reader | ||
| .gitignore | ||
| .gitmodules | ||
| README.md | ||
| build.gradle | ||
| dependencies.gradle | ||
| example-nick.bat | ||
| gradle.properties | ||
| gradlew | ||
| gradlew.bat | ||
| have_fun.bat | ||
| settings.gradle | ||
README.md
CAN file processing
- split trace file by packet ID
- per-ID comparison of multiple trace files
- counter bit region detection
- charting using MegaLogViewer
gradlew :reader:shadowJar
java -jar reader/build/libs/reader-all.jar "C:\stuff\rusefi_documentation\OEM-Docs\VAG\2006-Passat-B6" -filter passat-back-and-forth-60-seconds -dbc opendbc/vw_golf_mk4.dbc
CAN playback
CAN playback using PCAN on Windows or SocketCAN on Linux.
gradlew :playback:shadowJar
java -jar playback/build/libs/playback-all.jar playback/src/main/resources/atlas.trc
CAN decoding hints
CAN log file utilities to help me work with https://github.com/brent-stone/CAN_Reverse_Engineering and https://github.com/HeinrichG-V12/E65_ReverseEngineering
- turning ignition on (wake up)
- OEM ECU remove, turning ignition on (wake up)
- turning ignition off (shutdown)
- from ignition ON cranking and idling
- just idling
- ignition on, engine not running, press clutch four times
- ignition on, engine not running, brake pedal three times
- ignition on, engine not running, throttle pedal from 0% to 50%, to 0%, to 100%, to 0%
- engine running, rev from 1500 rpm to 3000 rpm