CANDY

Candy is a can frame viewer that can show live can frames, at a reasonable speed.

epx is used to diplay the can frames in a format that look something like

+--+----+ +-+-+-+-+ +--+--+--+--+--+--+--+--+
|ID|Freq| |X|R|E|L| |01|02|03|04|05|06|07|08|
+--+----+ +-+-+-+-+ +--+--+--+--+--+--+--+--+

The ID field is in hex and is 3 hex digits wide (11 bits) if the basic frame format is used. If the frame is in extended frame format (X flag) then 8 hex digits are used (29 bits). The X flag signals extended frame format and R is the request for transmission flag. E is the error frame marker, error frames are always produced by the local can stack it self. L is a length indication in range 0-8.

The rest of the fields are grouped into 8 groups of 8 bits each. Clicking on the group will toggle the base from 16->10->2->8->16. This make it simple to change format when looking for patterns among the CAN frames.

Internally you can change the order of bits and combine them into bigger groups etc. Editing the groups graphically on in the window is on the TODO list.

The easiest way to start candy is:

erl -s candy

This will show a blank window with a cyan background. candy initialize the can_udp backend by default. In the shell you may add other can backends at will. Or backends may be added by configuration file (README can)

Commands

Key commands used on selected elements:

X              Hexa decimal format
D              Decimal format
B              Binary format
O              Octal format
C              Color format	
---
G              Group selected bits
Shift+G        Ungroup selected bits
H              Sort Low -> High frames by frame id
Ctrl+H         Sort High -> Low frames by frame id	
1-8            Split in groups of 1 to 8 bits
Ctrl+S         Save information to $HOME/candy.txt

Other key commands

Q              Quit application
Up             Arrow up, scroll up
Down           Arrow down, scroll down
PageUp         Page up, scroll one page up
PageDown       Page down, scroll one page down
Alt-Up         circulate bitrate up  (125K,250K,500K)
Alt-Down       circulate bitrate down (500K,250K,125K)

candy.txt format

The candy.txt file is generate with hitting Ctrl-S, if a bit group is selected then that bit will be saved in the following format.

single selection

<frame-id> <byte-index> <byte-mask> <match-on> <match-off>

Example

0x123 4 0x20 0x20 0x00

Lines not starting with a digit are assumed to be comments and are ignores. A decent choice of leading characters for comments could be a space or a ';'.

multiple selection

<frame-id1> <byte-index> <byte-mask> <match-on> <match-off> ...
<frame-id2> <byte-index> <byte-mask> <match-on> <match-off> ...
...

make AppImage

erl -config candy.config -s candy -s servator make_appimage candy
[close candy window]
strip candy.AppDir/bin/*
appimagetool -n candy.AppDir