IDC Sequence File Syntax
IDC can read sequence files with the following general syntax:
[channel specifier-]<ECU id> <Diagnostic request bytes>;[wait];[ECU name and request description];[subnode id];[PIN=code];[AREA=code]
where channel specifier, if specified, is an integer specifying a can channel number followed by a hyphen, ECU id is the ECU identifier of a diagnostic request, Diagnostic request bytes are the hexadecimal codes of the diagnostic request, wait is the time in milliseconds to wait after a request until the next, ECU name and request description is a textual description of the target ECU and the diagnostic request, subnode id is the subnode address of the ECU, if used, PIN code is the secret code used for security access, if required, and AREA is the security access area code.
An example sequence like would be:
0-7E0 22 F4 0D;;ECM Bosch EDC16C_Y286 I5D Bosch EDC16C Diesel\Read Data By Identifier\Vehicle speed
Sequence file lines starting with # or // are treated as comments and ignored.
Sequence file lines starting with > are treated as commands.
Variables
Variables can be assigned values. The only valid data types are integers and diagnostic responses. This sets the variable 'foo' to the value 1:
> set foo 1
When referencing a variable, the '$' symbol before the name gives the variable's value, i.e. to set variable 'x' to the value or variable 'foo' is done as follows:
> set x $foo
To set a variable to a diagnostic response use the special keyword '$$' as follows:
> set foo $$
This will set the variable 'foo' to the response to the diagnostic request on the line following immediately after the directive.
Variables containing diagnostic responses can be used in subsequent diagnostic requests, as the following example illustrates.
> set x $$
1001 22 20 07
1001 2E A2 20 $x[3] $x[4]
Note how the individual bytes of the variable 'x' are referenced in the second request using '$x[n]' where n is the byte offset of the response starting at 0.
Integer variables can be increased or decreased by a value, as follows:
> set x 1
> set y 2
> incr x 2
> decr x $y
This would increase variable 'x' from 1 to 3, and then decrease it by 2 (the value of y).
Multiplication and division by a value is as follows:
> mult x 1000
>div x 100
There are a number of built-in special purpose variables, as listed in Table 1.
| Name | Meaning | Type |
|---|---|---|
| start | Time in milliseconds since start of idc | Integer |
| epoch | Time in seconds since the unix epoch | Integer |
| resplen | Length in bytes of last diagnostic response | Integer |
| majver | Major version number of idc | Integer |
| minver | Minor version number of idc | Integer |
Labels
Lebels define positions in the sequence file that can be jumped to by the 'jnz', 'jz' and 'goto' commands.
>label name
This defines a label with the name "name".
Control Flow
The control flow of a sequence file can be altered by jumping to a label, using 'jnz', 'jz' and 'goto' commands. The 'jnz' and 'jz' takes a variable name as first parameter and a label as the second. If the value of the variable is zero (0), 'jz' will jump to the specified label, whereas 'jnz' will jump if it is not zero. The 'goto' command takes just a label as argument. For example:
> jz foo name
> jnz foo name
> goto name
The 'quit' command finishes execution of the sequence file.
Timing
The execution of the sequence file can be paused for a specified time using the 'wait' command. For example:
> wait 100
> set foo 1000
> wait $foo
The first of the above commands waits for 100 milliseconds, and the second waits for one second (the value of integer variable 'foo').
The time in milliseconds to wait for diagnostic responses after a request can be changed by the 'timeout' command.
> timeout 5000
This sets the timeout to 5 seconds.
The special variable name 'epoch' can be used to get the time in seconds since the unix epoch. The special variable name 'start' can be used to get the time in milliseconds since the start of the sequence file execution.
Printing
To print strings, including values of variables, to the output result file, use the 'print' command. For instance:
> print "Time since start is $start milliseconds. Value of foo is $foo"
To print debug output to the logfile, use instead the 'debug' command, with a debug level from 1 to 5 as first argument.
> debug 2 "This is a debug message"