Ken Shirriff writes, “The BeagleBone Black is an inexpensive, credit-card sized computer that has two built-in microcontrollers called PRUs. While the PRUs provide the real-time processing capability lacking in Linux, using these processors has a learning curve. In this article, I show how to run a simple program on the PRU, and then dive into the libraries and device drivers to show what is happening behind the scenes.”
More details at Ken Shirriff’s blog.