Module dbc 

DBC files: what the frames of a CAN bus mean.

A DBC file names each message by its id (BO_) and the signals packed in its data (SG_): start bit, length, byte order, sign, factor and offset, unit, and for a multiplexed message which value of the multiplexer selects each signal. VAL_ names a signal’s values, SIG_VALTYPE_ marks a float signal, and CM_ comments on messages and signals. Parsed by hand; every count and length is bounded.

DBC files are found on the format search path, as FIX dictionaries are: a .dbc file applies to every interface, and a TOML file of kind = "dbc" names a DBC file (file) and the interface it applies to ([match] interface = "can1"). --dict FILE is read over them. A later file’s message of an id takes the place of an earlier’s.

Structs

Dbc

One DBC file and what it applies to.

Message

One message.

Signal

A signal’s place in its message and what its value means.

Enums

Mux

How a signal takes part in multiplexing.

Constants

MAX_FILE

The largest DBC file read.

Functions

integer

signal’s value in data as an integer of its sign, before factor and offset.

is_dbc_toml

Whether a TOML file is a DBC reference (kind = "dbc") rather than a format spec.

load

Read the DBC file path, or the DBC a kind = "dbc" TOML file names. Ok(None) for a TOML file of another kind.

parse

Parse the text of a DBC file named name.

physical

signal’s physical value in data: factor and offset applied, a float signal read as one.

present

Whether signal is present in a frame whose multiplexer reads mux.

raw

The raw bits of signal in data, or None when the data is too short to hold them.