The PRU compiler (clpru) is a TI proprietary compiler, free but licensed. It is pre-installed on BeagleBones. There's also a gcc compiler‡, but I don't know anything about it.

‡ https://github.com/dinuxbg/gnupru

I didn't know about this! My last experience messing around with compiling for the PRUs was really frustrating - I gave up after about three days' screwing around with freeware tools that didn't work.

Could you point to where the PRU compiler is located on the BeagleBone file tree? I'd like to try this out!

The TI PRU compiler is at /usr/bin/clpru on my BeagleBone (from Adafruit, with Debian). If it's not on your BeagleBone, you can download it here: http://elinux.org/Beagleboard:BeagleBoneBlack_Debian#TI_PRU_...

I'd recommend using the CCS IDE (as I describe in the article) rather than the command line compiler, but it's up to you. You'll still probably encounter frustration - it's not an Arduino experience for sure.

I think a lot of my frustration stemmed from NOT using CCS. Maybe I should just bite the bullet and do that...

Texas Instruments provides Code Composer Studio (CCS). It's about $800 a seat (version that I have) but there is a free version to use with the Beaglebone. See here http://processors.wiki.ti.com/index.php/Download_CCS

Also you don't necessarily need the IDE to compile with the PRU. The compiler itself is freeware, and is some sort of fork of the compiler line they developed for their DSPs.