Some reads on PRUs:

• https://hackaday.com/2014/06/22/an-introduction-to-the-beaglebone-pru/
• https://www.embeddedrelated.com/showarticle/603.php
• https://www.embeddedrelated.com/showarticle/586.php
• https://github.com/beagleboard/am335x_pru_package