J1939

= SAE J1939 in Linux =

overview
See also on Wikipedia.

SAE J1939 defines a higher layer protocol on CAN. It implements a more sophisticated addressing scheme and extends the maximum packet size above 8 bytes. Several derived specifications exists, which differ from the original j1939 on the application level, like MilCAN, NMEA2000 and especially ISO-11783 (ISOBUS). This last one specifies the so-called ETP (Extended Transport Protocol) which is has been included in this implementation. This inclusion results in a maximum packet size of ((2^24)-1)*7 bytes

Specifications

 * SAE J1939-21 : data link layer
 * SAE J1939-81 : network management
 * ISO 11783-6 : Virtual Terminal (Extended Transport Protocol)

Build the kernel (necessary)
$ git clone linux $ cd linux $ git remote add j1939 git://github.com/kurt-vd/linux $ git remote update j1939 $ git merge j1939/j1939-vX.X   $ make etc.

With j1939-vX.X the branch that matches the closest, but not higher, with your linux version.

Build can-j1939-utils (recommended)
$ git clone git://github.com/kurt-vd/can-utils $ cd can-utils $ make etc.

Or you may merge the j1939 changes into any other can-utils version. This should be fairly simple.

If the branch of linux-can-j1939 that you merged into your kernel was for version 3.7 or higher, use the j1939-v6 branch of can-j1939-utils.

Build iproute2-j1939 (recommended)
$ git clone git://github.com/kurt-vd/iproute2 $ cd iproute2 $ git checkout j1939-vX.X   $ make etc.

With j1939-vX.X the branch that matches the closest, but not higher, with your linux version.

Or you may merge the j1939 changes into any other iproute2 version. This may be a little more complicated.

Getting Started with J1939
First get a can0 bus on your system.

$ modprobe vcan $ ip link add can0 type vcan $ ip link set can0 up

Now start j1939.

$ modprobe can-j1939 $ ip link set can0 j1939 on

Now you should be able to use can0 as a j1939 CAN device.