Hi,


I’m completely new to both Beaglebone and Embedded Linux, but I decided to 
learn both in order to use Beaglebone Black as a development environment 
for a project which needs to include Can Bus interface. This forum and 
Molloy’s book are huge help of course, but some topics do require more info 
to complete the picture.

In order to enable CanBus on Beaglebone, I did all the steps described in 
various places including the book – 


a) GPIO configuration using BB-CAN1-00A0.dtbo device tree overlay,

b) LKM deployment using modprobe and finally

c) Interface enabling using the ip link set and ifconfig <> up command.


This all makes sense, but I still have a few questions:


a) In order to do these three steps automatically on bootup, it is 
necessary to edit uBoot.txt (which I did) and that will take care of GPIO 
configuration. Editing /etc/network/interfaces will take care of interface 
enabling, but I still don’t understand what is the way to automatically 
load necessary Kernel modules.


b) Also, my understanding at the moment is that these modules are a part of 
SocketCan network protocol base driver, but I would appreciate if someone 
can confirm (or not) this.


c) Right after power-up, lsmod tells me that c_can_platform is loaded, 
together with it’s dependancies – c_can and can_dev. What is the reason 
these two were loaded but not the can_raw which is mentioned as required in 
every tutorial? Loading of can_raw also causes it’s dependency – can module 
to load. How come this one was not loaded automatically with others?


d) Finally, same as some previous posters I see a problem with pins. After 
enabling the can0 interface I can see it being loaded using ifconfig 
command. I can use it in the loopback mode using /can-utils/candump can0 & 
followed by /can-utils/cansend can0 123#123456.

Howeveer, it can’t be uses for the actual physical connection as all 
relevant pins are reported as not configured: for pins 19, 20, 24, 26, I 
get: config-pin -q P9_26 à P9_26 pinmux file not found! And Pin has no 
cape: P9_26.  I do have Waveshare RS485/Can Cape connected to the BBB.

Thanks a lot,


Nick

 

 

 

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