CAN bus Linux driver
From ArmadeusWiki
The current CAN bus driver uses SocketCAN API which is now the official CAN API for Linux. SocketCAN is based on the Linux socket. Further details can be found on the links at the bottom of this page.
Warning: Please ensure that you use the trunk version of armadeus (kernel linux-2.6.38.1 is required) before effectuate the operations described on this page! |
Driver installation
$ make linux26-menuconfig
Networking support ---> <M> CAN bus subsystem support ---> --- CAN bus subsystem support <M> Raw CAN Protocol (raw access with CAN-ID filtering) <M> Broadcast Manager CAN Protocol (with content filtering) CAN Device Drivers ---> <M> Virtual Local CAN Interface (vcan) <M> Microchip 251x series SPI CAN Controller
$ make
- Reflash kernel and rootfs
Usage
- Load all the needed drivers:
modprobe can modprobe can-dev # if > armadeus-3.4 modprobe candev # if <= armadeus-3.4 modprobe can-raw modprobe mcp251x
- Set the bitrate before all operations (if > armadeus-3.4 only)
Example: Set the bitrate of the can interface can0 on 125kbps
ip link set can0 up type can bitrate 125000
If your version of armadeus is down or equal to the 3.4 version, the baudrate is fixed to 250kbps. To change this value, please upgrade your armadeus version.
Quick test
Once the driver installed, the CAN interface has to be started like a standard net interface
# ifconfig can0 up
and can be stopped like that:
# ifconfig can0 down
The socketCAN version can be retrieved like that:
# cat /proc/net/can/version
The socketCAN statistics can be retrieved like that:
# cat /proc/net/can/stats
Userspace tools
- Several tools are provided by socketCAN:
- candump: dump traffic on a CAN network
- cansend: simple command line tool to send CAN-frames via CAN_RAW sockets
- cangen: CAN frames generator for testing purpose
- canplayer: send CAN frames from a file to a CAN interface
- These tools can be compiled and installed on the target by means of the Buildroot menuconfig:
$ make menuconfig
Package Selection for the target ---> Networking ---> [*] Socket CAN [*] install test tools
$ make
then, reflash your rootfs.
Links
- https://www.ridgerun.com/developer/wiki/index.php/How_to_configure_and_use_CAN_bus (How to configure and use CAN bus)
- http://developer.berlios.de/projects/socketcan/ (CAN Linux Driver)
- http://ww1.microchip.com/downloads/en/DeviceDoc/21801e.pdf (MCP2515 datasheet)
- http://www.kvaser.com/can/protocol/index.htm (CAN introduction)