I do not know a lot about ST micro MCUs, but on the outside it seems to be slower than a single PRU. At 72Mhz. But sometimes operating frequency does not mean everything . . .
On Fri, Apr 17, 2015 at 12:00 PM, William Hermans <[email protected]> wrote: > Here, this is a link for some resources. > > http://elinux.org/Ti_AM33XX_PRUSSv2 > > My knowledge of the PRUs is rather limited, and I'd hate to give you bad > information. That link has external resource links where you can find lots > of projects / information. > > The "TRM" ( technical reference manual ) will probably be a big help. > > On Fri, Apr 17, 2015 at 11:49 AM, William Hermans <[email protected]> > wrote: > >> PRUs are 200Mhz with many single cycle instructions >> >> On Fri, Apr 17, 2015 at 9:45 AM, Frédéric <[email protected]> wrote: >> >>> Le Friday 17 April 2015, William a écrit : >>> >>> Thanks for your answer. >>> >>> > I think what you want to do is possible, but really depends largely >>> > on how fast you expect it to be. The PRUs have access to many pins on >>> > the board, a few of which can be accessed in a single cycle, if >>> > memory serves me correctly. Less than 32 total between both PRU's I >>> > think. >>> > >>> > For those who know much more than I on this subject to answer, I >>> > think you will have to provide a bit more information. At least how >>> > fast you expect your setup to be. >>> >>> Servos are driven with a 500µs-2500µs pulse width, every 20ms; the >>> pulse width gives the servo position (1500µs for neutral). >>> >>> For the sync. variation, I don't know exactly what speed I use. I may >>> send a new position to all legs (18 servos) every 0.1s (I think I'm >>> limited by the python side, as I have to recompute all positions). >>> >>> If we use 1000 intermediate points (which is huge), it will need a >>> refresh of pulses widths every 100µs, which allows thousands PRUs >>> intructions! >>> >>> > With that said however, I do not think the rPI can even come close to >>> > how fast this could be done on the BBB . . . >>> >>> Yes, the RPi solution way was to keep the Veyron servo controller, >>> which does the servo sync. >>> >>> BTW, this board uses a stm32F103; don't know how fast it is compared >>> to PRUs... >>> >>> -- >>> Frédéric >>> >>> -- >>> 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 [email protected]. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> > -- 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 [email protected]. For more options, visit https://groups.google.com/d/optout.
