I am trying to map some functionality on the PRU subsystem. To implement these functions I will need at least two timers.
In the am335x_tech-ref_c.pdf (where the PRU is still described in detail) some timers are mentioned: one in the ECAP module, and one in the IEP module.
I have managed to implement the APWM function present in the ECAP module, so that is one timer taken care of.
Now one timer left.
I am aware that the PRU can reach the DMTIMER subsystem, but polling a DMTIMER on a regular basis has not a good feel, because this will create additional load on the L3/L4 bus.
So I am searching for one more timer. The IEP timer seems to be present only on the AM3359, so I cannot use that timer.
Is there another timer that can be used or trick to implement? For instance, I do not plan to use the UART present in the PRU, but could I use the receiver timeout interrupt? – see 4.7.2.5.3.1 of the pdf.