Are you loading any overlays? The device tree loaded during system startup
does not enable PRU. You have to switch the subsystem on by loading an
overlay, which will load the driver and take care of all the operations
necessary to switch PRUSS on. If you don't have your own overlay yet, try
the NIXIE overlay from Angstrom distro or use this example:
https://github.com/piranha32/IOoo/blob/master/dts/tlc5946-00A0.dts
Before you load the example overlay you have to compile it:
dtc -O dtb -o ../bin/gpio_hd44780-00A0.dtbo -b 0 -@
gpio_hd44780-00A0.dts
Copy the .dtbo file to /lib/firmware and load it:
echo tlc5946 > /sys/devices/bone_capemgr.*/slots
After loading the overlay you should see PRU kernel module loaded and
device files in /dev.
j.
On Tue, Oct 1, 2013 at 9:36 PM, Bit Pusher <[email protected]> wrote:
> Thanks Jacek, this is very helpful; is there any chance you canalso point
> me to a link re:
>
> Make sure that you loaded overlay enabling PRU and that the PRU driver is
> loaded? Thanks again.
>
> Bit Pusher
>
> On Tuesday, October 1, 2013 6:45:16 PM UTC-4, Jacek Radzikowski wrote:
>
>> On Tue, Oct 1, 2013 at 6:13 PM, Bit Pusher <[email protected]> wrote:
>>
>>> /boot/dtbs\> sudo dtc -I dtb -O dts am335x-boneblack.dtb >
>>> am335x-boneblack.dts_orig
>>>
>>> -bash: am335x-boneblack.dts_orig: Permission denied
>>>
>>> any ideas? Thanks.
>>>
>>>
>> sudo dtc -I dtb -O dts am335x-boneblack.dtb >
>> /tmp/am335x-boneblack.dts_orig
>>
>> Instead of /tmp you can use any other directory in which you can write.
>> Sudo executes only dtc with root privileges, redirection is done by your
>> own shell.
>>
>>
>> On a separate issue (that I am also stuck on),
>>> in ~/pru/am335x_pru_package/**pru_sw/example_apps\>
>>>
>>> I copied pasm to pasm_2 in ~/pru/am335x_pru_package/**pru_sw/utils and
>>> was able to assemble and make example; did a modprobe uio_pruss as
>>> recommended by boxysean, but am now stuck at:
>>>
>>> ~/pru/am335x_pru_package/pru_**sw/example_apps/bin\> sudo
>>> ./PRU_memAccessPRUDataRam
>>>
>>> INFO: Starting PRU_memAccessPRUDataRam example.
>>> prussdrv_open open failed
>>> ~/pru/am335x_pru_package/pru_**sw/example_apps/bin\>
>>>
>>
>> Make sure that you loaded overlay enabling PRU and that the PRU driver is
>> loaded. You can also use strace to see where the program fails. If the
>> driver is not loaded it will fail on opening device file from /dev/ or a
>> file from /sys (don't remember exactly).
>>
>> I tried Radzikowski’s magical hack. Create /usr/local/src/pruss_**magic_jr,
>>> but this didn't work.
>>>
>>
>> This bug has been fixed a long time ago and PRU works fine without doing
>> magical tricks.
>>
>> j.
>>
>> --
>> Given a choice between two theories, take the one which is funnier
>>
> --
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