Programmable real-time units – an introduction

Now it's time for hardware magic, for serious real time, and a shift away from mere software mods on the kernel.

It's time for Programmable Real-Time Units And Industrial Controller Subsystem, also known as PRU-ICSS, or PRUs. How's that for a mouthful? More techno-acronyms are always so helpful and delicious. OK. Let's deconstruct it.

PRUs are specialized chips on the BeagleBone Black that give you real time task control over your system. These two 32-bit microcontrollers are actually separate CPUs from the main CPU and the operating system. That's right: PRUs are separate hardware. This means they are not reliant on the core kernel and are more efficient at accessing I/O pins and driving real time events.

Having onboard PRUs is one of the BBB's big differentiators in the microcomputer market. Real-time hardware control typically requires adding on daughterboards such as FPGAs (another big scary acronym) that boost your system's mojo. Using PRUs...