VintageNetCan adds support to VintageNet for CAN bus connections, through IP and Socketcand commands.

Assuming that your device has a CAN bus hardware and drivers, all you need to do is add :vintage_net_can to your mix dependencies like this:

def deps do
  [
    {:vintage_net_can, github: "valiot/vintage_net_can", targets: @all_targets}
  ]
end

The CAN bus overlays and drivers are not shipped by default in the official Nerves Targets, you can follow the next slides to add all requirements or check the following Nerves Custom System.

Basically, the following options were added:

# linux-xxx.defconfig
CONFIG_CAN=y
CONFIG_CAN_MCP251X=y

# nerves_defconfig 
BR2_PACKAGE_LIBSOCKETCAN=y
BR2_PACKAGE_CAN_UTILS=y
BR2_PACKAGE_IPROUTE2=y
BR2_PACKAGE_SOCKETCAND=y

CAN bus interfaces typically have names like "can0", "can1", etc. when using Nerves.

An example of the most basic CAN bus configuration is:

config :vintage_net,
  config: [
    {
      "can0",
      %{
        type: VintageNetCan,
        can: %{bitrate: 500_000}
      }
    }
  ]

You can also set the configuration at runtime:

iex> VintageNet.configure("can0", %{type: VintageNetCan, can: %{bitrate: 500_000}})
:ok

Depending on your hardware this mode may or may not be available. An example of a CAN FD configuration is:

config :vintage_net,
  config: [
    {
      "can0",
      %{
        type: VintageNetCan,
        can: %{
            bitrate: 500_000,
            fd: "on",
            dbitrate: 1_000_000,
            berr_reporting: "on"
          }
      }
    }
  ]

VintageNetCan also provides access to CAN interfaces on a machine via a network interface by using [socketcand] deamon The communication protocol uses a TCP/IP connection and a specific protocol to transfer CAN frames and control commands.

Here's a CAN & Socketcand configuration:

iex> VintageNet.configure("can0", %{
    type: VintageNetCan,
    can: %{bitrate: 500_000},
    socket: %{
      port: 29536,
      can_interfaces: ["can0"],
      linked_interface: "lo",
    }
  })
:ok

In the above, the CAN interface is exposed by link it to the Local Loopback interface (lo) using the 29536 port.

To see all possible parameters, please refer to the following references:

• SocketCand.
• VintageNetCan.SocketCanConfig.
• VintageNetCan.CanConfig.

There are CAN-specific properties. See vintage_net for the default set of properties for all interface types.