> > *or by using pin(s) the PRU's can switch modes for fast. For something > like say a buffer<->external memory. This way would also be far more > complex, but should be vastly faster than using universal-io.* >
SO what I mean by being far more complex. Is that you would have to write an external Linux binary, that would communicate with the PRU(s). Then, you would also need to write code for the PRU(s), so the programmable real time unit(s) could communicate with your Linux binary. Typically, I would think this would be fairly useless, unless done for demonstration purposes. As the PRUs are really meant for high speed "applications", where speed is paramount - to a point ( 200Mhz ). Adding Linux to the mix alone would slow things down considerably, let alone Nodejs. As non real time Linux flavors only have around a 10ms timing resolution, and sometimes it can be far higher ( 100ms + ). Anyway, probably moot for your case anyhow . . . On Tue, Jan 6, 2015 at 6:07 PM, William Hermans <[email protected]> wrote: > *The function digitalRead returns the value of the pin does it not?* >> > > This I do not know first hand as I have never used bonescript. What I can > say is that typically, when calling an executable directly from Nodejs ( > which is what bonescript uses - Nodejs ), you need to use a callback to > capture the output of that executable *if* you wish to use that value from > within the script. > > What I do imagine, as far as how bonescript works. Is that it directly > calls an executable of some sort ( custom, or Linux command ), which then > returns a value depending on which mode the pin is set as. Jason Kridner > should know for sure since he wrote the library, and I could be wrong. I > never really examined his code all that well, before I decided it was not > for me. > > *Basically what I ask is, if reading the return value of the digitalRead >> is enough, of should I capture the value of the pin via a callback >> function.* >> > > Ok, so if bonescript does in fact return a value, and if correct ( > without a callback ), then there should be no problem. You could / should > test the value to make sure it is correct though. > > *I am writing a small program where I interchange the mode of a pin as >> input and output. I am having difficulties doing that. I am a newbie in >> javascript, but I am wondering if that is possible at all.* >> * Thanks in advance* >> > > I have read on these groups from various people that using a single pin ( > GPIO - read / write ) is possible. However, I am left wondering in which > case that would be useful. Whatever the case, digitalRead would only work > when the pin is configured as GPIO -> IN. > > Two ways I *think* you may be able to do this is using . . . > > https://github.com/cdsteinkuehler/beaglebone-universal-io - This would be > slow-ish, but you could call config-pin directly from Nodejs. > > or by using pin(s) the PRU's can switch modes for fast. For something like > say a buffer<->external memory. This way would also be far more complex, > but should be vastly faster than using universal-io. > > > > On Tue, Jan 6, 2015 at 3:29 PM, Vasilis Iliadis < > [email protected]> wrote: > >> The function digitalRead returns the value of the pin does it not? >> Basically what I ask is, if reading the return value of the digitalRead is >> enough, of should I capture the value of the pin via a callback function. >> I am writing a small program where I interchange the mode of a pin as >> input and output. I am having difficulties doing that. I am a newbie in >> javascript, but I am wondering if that is possible at all. >> Thanks in advance >> >> On Jan 6, 2015 2:44 AM, "William Hermans" <[email protected]> wrote: >> > >> > How would you plan on getting the information back from digitalRead if >> not by using a javascript callback ? >> > >> > Also, more information is needed. e.g. what is your program goal ? >> > >> > On Mon, Jan 5, 2015 at 2:38 PM, 'Vasilis Iliadis' via BeagleBoard < >> [email protected]> wrote: >> >> >> >> I am playing with GPIO and digitalRead in bonescript. I noticed that >> although digitalRead is fairly fast the callback function takes a while. I >> am asking the group if I should wait for the callback to be triggered or >> just calling digitalRead is enough!. >> >> >> >> Thanks >> >> >> >> -- >> >> 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 a topic in the >> Google Groups "BeagleBoard" group. >> > To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/beagleboard/ro7_iOAKamM/unsubscribe. >> > To unsubscribe from this group and all its topics, 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. >> > > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. 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