Enabling the PRU -- Debian


I’m looking for how to enable the PRU on my beaglebone black, with pre-packaged Debian installed on it. To get it enabled on my Angstrom bone, I had simply manually edited the device tree file, am335x-boneblack.dtb, found in /boot. However, I can not find this file, or an obvious equivalent, on my Debian bone. Any ideas?

The error I get when trying to use the PRU now is “prussdrv_open open failed”


Check out Charles Steinkuehler's beaglebone-universal-io
Accessing the PRU functionality is just "config-pin overlay cape-universal" and to configure, for example, P8-15 as a GPI input, "config-pin P8-15 pruin". Choose pins that are not used by the hdmi or emmc, or disable the hdmi [and/or emmc] functionality by modifying /boot/uboot/uEnv.txt [look for cape_disable].
Depending upon the age of your version of Debian, you might need to download from the repository to get good versions of the cape-universal overlay and config-pin. If you download and install, Debian has it own version of the cape-universal overlay so rename the dtb before moving it to /lib/firmware. Also, config-pin might be located in several places. So when you install it in /usr/bin, be sure to start it with the complete path name "/usr/bin/config-pin".