CanDbc

Purpose:

Provide CANBus communications between Can Devices using basic can messages. It reads a *.dbc which provides the information on the parameters to monitor and creates the CyFlex variables to store the data. See Notes for a description of how the .dbc file is composed.

Enter:

CanDbc <filename.dbc> [usbpath1] [baud1=usbbaud1] <filename2.dbc>
[usbpath2] [baud2=usbbaud2] [time=clock_time]
[name=reg_name] [seed=<hexvalue>] [cpu=CPU_bit] [priority] [debug]

Where:

filename	Specify the name of the DBC file describing the data monitor. The DBC file describes the communications on a single CAN Network.
usbpath1	Optional. Specify a USB device as desired.
baud1	Optional. Specify a baud rate for a connected USB device.
filename2	Optional. Specify the name of a second DBC file to use to send a channel on an AC2 card. If specified, specify a second USB device.
usbpath2	Optional. Specify a second USB device.
baud2	Optional. Specify the baud rate for a second connected USB device.
time	Optional. Specify the update time. The default is 10.
name	Optional. Specify the desired register name. The default name is CanDbc.
seed	Optional. Specify a seed hex value for CCP protocol.
cpu	Optional. Specify a bit mask value to set on which CPU to function.
priority	Optional. Specify the task priority.
debug	Optional. Used to display incoming messages to the console

Example:

CanDbc /specs/cyflex.dbc 12 &
The above command starts the task at priority 12 reading the /specs/cyflex.dbc.

CanDbc /specs/cyflex.dbc time=10 12 &
The above changes update time to 10, task at priority 12, reading the /specs/cyflex.dbc.

CanDbc /specs/cyflex.dbc /specs/cyflex2.dbc 12 &
The above command starts the task at priority 12 reading the /specs/cyflex.dbc on one bus and reading /specs/cyflex2.dbc on a second bus.

CanDbc /specs/cyflex.dbc /dev/pcanusb0 12 &
The above uses USB can device /dev/pcanusb0 with priority 12

CanDbc /specs/cyflex.dbc /dev/pcanusb0 baud1=250000 12 &
The above uses USB can device /dev/pcanusb0 with priority 12 at baudrate 250000

CanDbc /specs/cyflex.dbc /dev/pcanusb0 cyflex2.dbc /dev/pcanusb1 12 &
The above uses USB can device /dev/pcanusb0 with priority 12 reading the /specs/cyflex.dbc on one bus and reading /specs/cyflex2.dbc on a second bus.

CanDbc /specs/cyflex.dbc /dev/pcanusb0 baud1=250000
/specs/cyflex2.dbc /dev/pcanusb1 baud2=125000 12 &
The above uses USB can device /dev/pcanusb0 with priority 12 reading the /specs/cyflex.dbc at baudrate 250000 on one bus and reading /specs/cyflex2.dbc on a second bus at baudrate 125000.

Candbc /specs/cyflex.dbc 12 seed=0x1234568 &
The above command starts the task at priority 12 reading the /specs/cyflex.dbc using a seed key of 12345678.

Candbc /specs/cyflex.dbc 12 cpu=8 &
The above command starts the task at priority 12 reading the /specs/cyflex.dbc running on CPU 3.

Notes:

Acceptable baud rates for USB are:
1000000
500000
250000
125000
50000
20000
10000
5000

Acceptable baud rates for cards:
1000000
800000
500000
250000
125000
100000
50000
20000
10000

Bit mask for a 4 core CPU:

0,1 = CPU 0
2,3,6,7,10 = CPU 1
4,5 = CPU 2
8,9 = CPU3

Can restart the bus connection by setting the event candbc_reset

If you are having the problem: error while loading shared libraries: libpcan.so, then you may be missing a library. Check whether you have the library with the command: rpm -qa | grep pcandriver. If nothing shows up the you are missing the library. Install with: sudo yum install pcandriver

Example .dbc file:
Normally the .dbc is generated by another application or already exists. Once the files exists, there are a few parameters that can be changed to determine what message is being sent or read. Here is a sample message from a .dbc, the carrots denote the number format and are not actually in the .dbc file:

   <1> <2>       <3>: <4> <5>
   BO_ 3221225472 MSG_NAME: 0 Vector__XXX
     <6> <7> :<8>|<9>@<10><11> (<12>,<13>) [<14>|<15>]”<16>” <17>
     SG_ Var1 : 48|16@1+      (1,0) [0|65000] “%”     Vector__XXX
     SG_ Var2 : 32|16@1+      (1,0) [0|65000] “none”  Vector__XXX
     SG_ Var3 : 16|16@1+      (1,0) [0|65000] “none”  Vector__XXX
     SG_ Var4 :  0|16@1+      (1,0)  [0|65000] “none” Vector__XXX

The BO_ indicates that this is a message
The number after the BO_ is the message ID in base 10. When making changes to the .dbc, most devices and manuals give the ID in hex. You need to manually convert that.
This is the message name
This does nothing in CyFlex.
This is just used as a brief description of the message and does 0nothing in CyFlex.
The SG_ indicates this is a signal for a variable
Is the variable name
the offest of bits at the start of a message. This indicates what bits to use when setting the cyflex variables. (This is normally stated in the device manual)
The size of the signal in bits. This indicates how many bits you use for the cyflex variable. (This is normally stated in the device manual)
This value indicates if the device and message being sent is LITTLE_ENDIAN or BIG_ENDIAN. 1 is LITTLE_ENDIAN, 0 is BIG_ENDIAN
The 10 is the ‘+’ sin above. – is for signed value, + is for unsigned.
This value is the factor used when calculating the value. It takes the raw value and multiples by the factor.
This value is the offset that is added after the factor has been multiplied.
physical_value = raw_value * factor + offset
Minimum value. The physical_value can not be lower than this
Maximum value. The physical_value can not be higher than this
This is the units to use in CyFlex
Just a description, not useful

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