DBC_File_Format_Documentation(7)

Vector 公司的 DBC 文件格式说明。这类DBC文件可以作为整车CAN网络的描述文件,可以描述各个CAN message(包括ID、传递参数的物理含义等)。

multiplexer_indicator = ' ' | 'M' | m multiplexer_switch_value ;

The multiplexer indicator defines whether the signal is a normal signal, a multi-plexer switch for multiplexed signals, or a multiplexed signal. A 'M' (uppercase) character defines the signal as the multiplexer switch. Only one signal within a

single message can be the multiplexer switch. A 'm' (lowercase) character followed by an unsigned integer defines the signal as being multiplexed by the multiplexer switch. The multiplexed signal is transferred in the message if the switch value of the multiplexer signal is equal to its multiplexer_switch_value.

start_bit = unsigned_integer ;

The start_bit value specifies the position of the signal within the data field of the frame. For signals with byte order Intel (little endian) the position of the least-

significant bit is given. For signals with byte order Motorola (big endian) the posi-tion of the most significant bit is given. The bits are counted in a sawtooth manner. The startbit has to be in the range of 0 to (8 * message_size - 1).

signal_size = unsigned_integer ;

The signal_size specifies the size of the signal in bits

byte_order = '0' | '1' ; (* 0=little endian, 1=big endian *)

The byte_format is 0 if the signal's byte order is Intel (little endian) or 1 if the byte order is Motorola (big endian).

value_type = '+' | '-' ; (* +=unsigned, -=signed *)

The value_type defines the signal as being of type unsigned (-) or signed (-).

factor = double ;

offset = double ;

The factor and offset define the linear conversion rule to convert the signals raw value into the signal's physical value and vice versa:

physical_value = raw_value * factor + offset

raw_value = (physical_value – offset) / factor

As can be seen in the conversion rule formulas the factor must not be 0.

minimum = double ;

maximum = double ;

The minimum and maximum define the range of valid physical values of the signal.

unit = char_string ;

receiver = node_name | 'Vector__XXX' ;

The receiver name specifies the receiver of the signal. The receiver name has to be defined in the set of node names in the node section. If the signal shall have no receiver, the string 'Vector__XXX' has to be given here.

Signals with value types 'float' and 'double' have additional entries in the sig-nal_valtype_list section.