There is an eCAP module in the processor that *perhaps* could be controlled via a PRU . . . but I have limited knowledge of that peripheral module, and no hands on . . .
On Sat, Sep 10, 2016 at 6:25 PM, Dennis Lee Bieber <[email protected]> wrote: > On Sat, 10 Sep 2016 15:04:23 -0700 (PDT), beezerlm > <[email protected]> declaimed the following: > > > > > I have a fairly simple motion control project I was planning on using > >an Arduino for, but my understanding is that the arduino's 16Mhz clock > >won't keep up with my encoder pulses. I will need to process a max of > >10,000 pulses per second. The project is to control 1 reciprocating > >pneumatic cylinder and to simply monitor the position and change direction > >at a programmable in/out position. Is this within the capabilities of the > >BBB? > > Rather fast for a motion encoder... I think my Kenwood transceivers > only produce 1000 pulses per rotation (well, maybe twice that to account > for direction), and spinning that dial faster than 1 rotation per second is > difficult. > > Using the /sys filesystem access is highly unlikely to keep up. > Memory > mapping the GPIO block might, or writing code for the PRUs (200MHz -- an > input loop using 100 instructions is still around 2MHz vs 10kHz) > > > OTOH: you may be looking at the matter from the wrong side. > > If you need to catch just a position to command some valves... > Perhaps > all you need is a simple hardware counter using the pulse stream as an > input. Full counter range scaled to the full encoder range, trigger set for > the specific count at the position to activate. Hardware counter is > probably much faster than a software loop. Getting to the counter from > plain Arduino may take some experimenting (I've not looked for a preset > library function) > https://sites.google.com/site/qeewiki/books/avr-guide/counter-atmega328 -> > CTC mode on counter 1 (16-bit) might be the type of operation you need. > > The BBB may have something similar, but a quick Google didn't > blind me > with anything obvious. Granted, to date the most ambitious thing I've done > is to prove that a DHT-11 humidity/temp sensor can not be read from Python > using the /sys filesystem access, nor from a C program using that mode > either. [Oh... And running the old HINT benchmark -- which, contrary to the > authors' expectations, didn't really scale well over 20 years: had to cut > the RUNTM parameter from 1.0 seconds to 0.001 seconds, and still got a > warning that the 16-bit integer benchmark was too fast for precision] > > -- > Wulfraed Dennis Lee Bieber AF6VN > [email protected] HTTP://wlfraed.home.netcom.com/ > > -- > 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]. > To view this discussion on the web visit https://groups.google.com/d/ > msgid/beagleboard/1la9tbpq2l2aui29c235hsndm6ik8eleun%404ax.com. > 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]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CALHSORob_C-bmhDKQ3LzJVH%2B6J5TginQ%3Ds2zAhZQ%3DOkf2ogk3w%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
