have you looked at Turnkey PRU deskclock application for BBB ?
I ‘published’ it exactly for those wanting to get started with the PRU… it uses mucho IPC (2 ring buffers)…
you would just need to get the ILI9341 device ($15 amazon), a bread board, some jumpers and an optional but highly recommended oscilloscope.
or if you prefer a simpler derivative, I have also published an image which drives the WS2812B led panel (mine was 16x16, but any smaller size could easily be driven). WS2812B support (neopixel)
both of these images use the PRU turnkey, using remoteproc and run fine from a uSD card. they both show how you can set up pins at boot time and drive the device from text, rather than ‘c’ calls. They also include ‘asm’ libraries for stack processing and IPC
details in the links that I provided
gomer