SBCD-AN-001: Using the CAN interface

Info Box Applies to SBC DIVA

History

Version	Date	Divelk version	Notes
1.0.0	November 2018	DIVELK 3.0.0

Introduction

SBC Diva has two CAN interface available on J40 connector. In order to enable the CAN interface, the correct device tree configuration must be passed to the kernel. The SBCD comes with both CAN interface enabled into its devicetree configuration.

CAN

The CAN peripherals are enabled on the device tree and it can be verified on the kernel dmesg

root@diva:~# dmesg | grep -i can
[    1.357744] CAN device driver interface
[    1.363041] c_can_platform 481cc000.can: c_can_platform device registered (regs=fa1cc000, irq=165)
[    1.373138] c_can_platform 481d0000.can: c_can_platform device registered (regs=fa1d0000, irq=166)
[    1.963737] can: controller area network core (rev 20120528 abi 9)
[    1.974626] can: raw protocol (rev 20120528)
[    1.978919] can: broadcast manager protocol (rev 20120528 t)
[  140.878039] c_can_platform 481cc000.can can0: setting BTR=1c02 BRPE=0000
root@diva:~#

The interfaces are also listed by the ifconfig command

root@diva:~# ifconfig -a
can0      Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
          NOARP  MTU:16  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:10
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
          Interrupt:165

can1      Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
          NOARP  MTU:16  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:10
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
          Interrupt:166

eth0      Link encap:Ethernet  HWaddr D0:FF:50:B3:5E:84
          inet addr:192.168.0.95  Bcast:192.168.0.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:62216 errors:0 dropped:0 overruns:0 frame:0
          TX packets:27598 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:75304059 (71.8 MiB)  TX bytes:4214320 (4.0 MiB)
          Interrupt:177

eth1      Link encap:Ethernet  HWaddr D0:FF:50:B3:5E:86
          BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:123 errors:0 dropped:0 overruns:0 frame:0
          TX packets:123 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:208530 (203.6 KiB)  TX bytes:208530 (203.6 KiB)

root@diva:~#

For enabling the CAN interface, it must be properly configured, for example:

root@diva:~# ip link set can0 type can bitrate 500000 triple-sampling on
root@diva:~# ifconfig can0 up
[  140.878039] c_can_platform 481cc000.can can0: setting BTR=1c02 BRPE=0000
root@diva:~#

cansend/candump

These SocketCAN utilities are present on DIVELK 3.0.0 root file system, so it is possible to send and receive packet simply via console commands:

Send packets example:

root@diva:~# cansend can0 -i 0x10 0x11 0x22 0x33 0x44 0x55 0x66 0x77 0x88
interface = can0, family = 29, type = 3, proto = 1
root@diva:~#

Receive packets example:

root@diva:~# candump can0
interface = can0, family = 29, type = 3, proto = 1
<0x001> [8] 01 02 03 04 05 06 07 08
<0x001> [8] 01 02 03 04 05 06 07 08
<0x001> [8] 01 02 03 04 05 06 07 08
<0x001> [8] 01 02 03 04 05 06 07 08
<0x001> [8] 01 02 03 04 05 06 07 08
<0x001> [8] 01 02 03 04 05 06 07 08
<0x001> [8] 01 02 03 04 05 06 07 08
<0x001> [8] 01 02 03 04 05 06 07 08