On 12/18/2014 3:39 PM, Charles Kerr wrote: > Was curious how many PRU pins (on each PRU) would be available for direct > mapping to R30/R31 of the PRU? One of the drawbacks I have with the BBB is > the limited direct access pins for output on both PRUs (after you use the > FLASH and a few peripherals).
I've got a pinout spreadsheet color-coded with PRU I/O (and GPIO bank numbers and other useful info) in github: https://github.com/cdsteinkuehler/beaglebone-black-pinmux/blob/hal_pru_generic/pinmux.ods If you're wanting to do output, you can use standard GPIO pins (accessed via the internal SoC L4_PERport1 bus) for all but the most timing sensitive applications. The writes get posted so they don't stall the PRU unless you do a bunch of them back-to-back, and the total latency is only around 100 ns. I've got timing details from tests I ran in some code comments: https://github.com/machinekit/machinekit/blob/master/src/hal/drivers/hal_pru_generic/pru_generic.p#L135-L163 For inputs, you really *DO* want to use the direct PRU pins, as it takes about 165 nS to read from a GPIO register via the SoC fabric, vs one 5 nS PRU clock for the direct inputs. -- Charles Steinkuehler char...@steinkuehler.net -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
