25Hz for PRU? :) hope its for educational purposes 22 нояб. 2013 г. 15:09 пользователь "Ozan Çağlayan" <[email protected]> написал:
> On Thu, Nov 21, 2013 at 10:49 PM, Charles Steinkuehler > <[email protected]> wrote: > > On 11/20/2013 9:30 AM, Ozan Çağlayan wrote: > >> I enabled the virtual PRU cape using device tree overlay and > >> successfully compiled and launched the blink code I found on the > >> internet but I'm quite confused in finding out which GPIO pins are > >> accessible/available from PRU. There are a lot of documents, specs, > >> pin names, gpio offsets, pinmuxes, etc. Do I need to apply a dtbo for > >> having 2xGPIO or are there already available ones that the PRU can > >> access? > > > > The PRU can control all GPIO pins, just write directly to the set and > > clear registers. > > So are the pr_pru[01]_* modes for some pins are just for faster GPI/GPO > access? > > > > > There are many ways to create a delay. The easiest would just be a > > software loop, or you can use the IEP timer documented in the latest PRU > > reference manual, or many other options. More detail about exactly what > > you're trying to do, what you've tried, and your design constraints will > > probably get you more useful help. > > Thanks for the pointers. A timer will be much easy if it is easy to > implement :) > > What I'm trying to do is to flicker 2 LEDs with different flickering > rates, say 15Hz and 18Hz or 18Hz and 19Hz (but not much than ~25Hz). > A userspace code will trigger this flickering and do another stuff. > Once it decides to stop the flickerings, it will notify the PRU and > the PRU will stop flickering/driving the LEDs. > But after some while the userspace code may again decide to start > flickering. So one possibility is to launch and terminate the firmware > each time but I don't know if loading the firmware and executing it > has a big overhead or not. Another is to use some busy waiting in the > firmware so that the code just does nothing unless the userspace code > tells him to start flickering. > > I don't know which one is easier though. > > Thanks again. > > > > -- > Ozan Çağlayan > Research Assistant > Galatasaray University - Computer Engineering Dept. > http://www.ozancaglayan.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]. > For more options, visit https://groups.google.com/groups/opt_out. > -- 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/groups/opt_out.
