Moxa TC-SW04-M12-4P-T [27/43] Tc cp02 db t configuring the socket can interface

TC-6000 Series Expansion Modules Software Installation and Programming Guide

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extends the Berkeley sockets API in Linux by introducing a new protocol family, PF_CAN, that coexists with

other protocol families like PF_INET for the Internet Protocol.

You can use the file control interface to read, write or control the CAN interface as a file for easy CAN

programming.

TC-CP02-DB-T: Driver Installation

The drivers for Moxa TC-SP04-DB44-T module include can.ko, can_raw.ko, can_bcm.ko, can_dev.ko,

sja1000.ko, and plx-pci.ko . These have all been pre-installed under:

/lib/modules/3.2.0-4-686-pae/updates/drivers/net/can

Some drivers will be loaded by the boot process when modules are inserted; others must be loaded manually,

using modprobe:

Moxa:~# modprobe can

Moxa:~# modprobe can_raw

Moxa:~# modprobe can_bcm

You may set modules to load automatically at boot by listing them in the /etc/modules file.

TC-CP02-DB-T: Configuring the Socket CAN Interface

After the modules have been loaded, the next step is to configure the CAN interface and start it as a standard

net interface. Here’s an example with bitrate 12500:

# ip link set can0 up type can bitrate 12500

# ip link set can1 up type can bitrate 12500

The SocketCAN information is stored under /proc/net/can; you can determine what version is being used by

using the cat command:

Moxa~:# cat /proc/net/can/version

and return usage/operating statistics thus:

Moxa~:# cat /proc/net/can/stats

TC-CP02-DB-T: Sample Script for the SocketCAN API

The following code is a working example of the SocketCAN API in use; this code sends a CAN packet using the

raw interface. It is based on the notes documented in the Linux Kernel

(https://www.kernel.org/doc/Documentation/networking/can.txt).

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <string.h>

#include <net/if.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <sys/ioctl.h>

#include <linux/can.h>

#include <linux/can/raw.h>

int

main(void)

{

int s;