SOLUTION - Missing /dev/rpmsg_pru30 and /dev/rpmsg_pru31

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Bruce Chidester

May 27, 2021, 1:00:11 PM5/27/21
to BeagleBoard
I am in the middle of struggling while introducing myself to the PRU. I want to contribute to the world to help some other struggling individual and this seems like the right place to post a solution.

I am using Beaglebone Black Rec C. 
Running the uboot_overlay_pru=AM335X-PRU-RPROC-4-19-TI-00A0.dtbo defined in /boot/uEnv.txt

If you do not see the /dev/rpmsg_pru3* devices and you expect them, the zip file I have attached has a working solution to make them show up. I believe the solution has a lot to do with the right resource file and the PRU code. They will not simply just show because you have 2 PRU's. This may seem obvious to the more advanced PRU people, but took me a couple of weeks to figure this (and other things) out.

Here are my results after days of trying to figure out the magic to get the devices to show up:

root@beaglebone:/home/debian/rpmsg_pru# ./

Once the devices show for you:

echo "test30" > /dev/rpmsg_pru30
echo "test31" > /dev/rpmsg_pru31

cat /dev/rpmsg_pru30
<Ctrl> - c

cat /dev/rpmsg_pru31
<Ctrl> - c

Mark Lazarewicz

May 27, 2021, 1:13:59 PM5/27/21
Very helpful post Bruce thanks. I am just a PRU observer. The resource file is discussed in some TI documents it's a way to let Linux understand what resources the PRU will need is what I understood.

I'm guessing the SDK examples I played with had this all set up.

My guess this file will be important if you use any DDR to store you're samples.

Great to know you are on the  path to success!!!!


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Bruce Chidester

May 28, 2021, 12:32:24 PM5/28/21
to BeagleBoard
Where's the "like" button?

Here it is -> LIKE

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