= Add PRU-ICSS loader/driver to RTEMS =

'''Student:''' Nils Hölscher

'''Mentors:''' Amaan Cheval, Kuan-Hsun Chen, Chris Johns, Sarvesh Patkar

'''Ticket:''' https://devel.rtems.org/ticket/3730

''' Development Blog:''' TBA

== Introduction ==
This Project intends to add the PRU support to RTEMS, using the Beaglebone Black (BBB). The BBB has an Texas Instruments AM3358 SoC [3][4] with an Programmable Real-Time Unit (PRU).
The PRU is able to connect to the SoC s i/o within one cycle.
This will enable the RTEMS community to develop heavily i/o dependent tasks on the Texas Instruments SoC s with PRUs.
For more Information about PRU see [5].

== Starting Point ==
Since the Beagle Board community already uses the PRU, I will start by trying out their drivers.[1][2]
After reproducing these results with the Linux, the drivers have to be ported to RTEMS to reproduce these Results on RTEMS.

== Proof of Concept ==
Since the PRU is designed to be more predictable than your normal CPU, it is able to access I/O peripherals in a deterministic manner.
This behavior will be used to demonstrate that code is running on the PRU and not the CPU.
The PRU is able to output a square wave with constant small wavelength on the BBB s Pins.
The SOC s CPU is not capable of this, due to pre-emptive behaviour of most OS s.

== References ==
[1] Drivers - https://github.com/beagleboard/am335x_pru_package

[2] PRU guide for BBB - http://www.righto.com/2016/08/pru-tips-understanding-beaglebones.html

[3] AM3358 TI Documentation - https://www.ti.com/lit/ds/symlink/am3358.pdf

[4] AM335x TI Technical Reference Manual - https://www.ti.com/lit/ug/spruh73p/spruh73p.pdf

[5] eLinux Pru Documentation - https://elinux.org/Ti_AM33XX_PRUSSv2