RIOT/tests/conn_can

tests/conn_can

Demo application for the CAN stack with conn_can interface.

Native prerequisites

For using the can stack on top of socketCAN, available for linux, you need:

• socketCAN (part of kernel starting from 2.6.25)
• install the 32bit version of libsocketcan:

if you're on a 64bit system:

sudo dpkg --add-architecture i386
sudo apt-get update
sudo apt-get install libsocketcan-dev:i386

On 32 bit you can just do the following:

sudo apt-get install libsocketcan-dev

Alternatively, you can compile from source:

wget http://www.pengutronix.de/software/libsocketcan/download/libsocketcan-0.0.11.tar.bz2

$ tar xvjf libsocketcan-0.0.11.tar.bz2

$ rm -rf libsocketcan-0.0.11.tar.bz2

$ cd libsocketcan-0.0.11

$ ./configure

compile in 32bits

./configure --build=i686-pc-linux-gnu "CFLAGS=-m32" "CXXFLAG

$ make

$ sudo make install


sudo ldconfig
/usr/local/lib

The default native configuration defines two virtual can ifaces to be used. Before running this test on native, you should create those:

sudo modprobe vcan
sudo ip link add dev vcan0 type vcan
sudo ip link add dev vcan1 type vcan
sudo ip link set vcan0 up
sudo ip link set vcan1 up

Usage

Adapt pin configuration in Makefile to match the used CAN transceiver (e.g. TJA1042_STB_PIN)

Build, flash and start the application:

export BOARD=your_board
make
make flash
make term

To initialize a CAN transceiver device (trx_id = 0)

init 0

To set a CAN transceiver device's (trx_id = 0) mode to TRX_NORMAL_MODE

set_mode 0 0

The CAN interfaces are registered at startup to the dll. The list of registered interfaces and their RIOT names can be retrieved with:

test_can list

To send a raw CAN frame, id 0x100 with 2 bytes of data 01 02 on interface 0:

test_can send 0 100 01 02

To send a raw CAN remote request frame, id 0x100 on interface 0 and datalenght 7:

test_can sendrtr 0 100 7

A remote request frame has a NULL payload but can have a specific data length code (DLC). Valid DLC val: 0..8

Two threads are launched to enable receiving frames. To receive raw CAN frames, ids 0x100 and 0x500 with thread 0 on interface 1, with 10s timeout:

test_can recv 1 0 10000000 100 500

A connection can be closed with its thread id, for instance:

test_can close 0

To send an ISO-TP datagram, first bind a connection with one of the threads, source id 700, dest id 708, thread 1 and interface 0:

test_can bind_isotp 0 1 700 708

Then send the data 01 02 03 04 05 0a 0b 0c:

test_can send_isotp 1 01 02 03 04 05 0a 0b 0c

To receive from an ISO-TP channel, it must be bound, then with the previous channel, and 10s timeout:

test_can recv_isotp 1 10000000

An ISO-TP channel can be closed with:

test_can close_isotp 1

You can also set a bitrate (this won't work on native with vcan, only with real interfaces, but then root access are needed), for instance 250000 bit/s with sampling point 87.5%:

test_can set_bitrate 250000 875

Linux CAN basic commands

Once the interfaces are set up, can-utils commands provide a way to send and receive raw CAN frames and ISO-TP datagrams.

For ISO-TP, an experimental module for linux can be found here. It needs to be loaded before trying to use ISO-TP protocol.

Here are some basics examples.

Send a raw CAN frame, id 0x100, data 00 11 22:

cansend vcan0 100#001122

Dump the traffic on a CAN interface:

candump vcan0

Send an ISO-TP datagram, source id 700, dest id 708, data 00 11 22 33 aa bb cc dd:

echo 00 11 22 33 aa bb cc dd | isotpsend -s 700 -d 708 vcan0

Receive ISO-TP datagram:

isotprecv -s 708 -d 700 vcan0

Please read commands help for more details on usage.