Programmable Realtime Unit. http://processors.wiki.ti.com/index.php/Programmable_Realtime_Unit_Subsystem
You can use this processors for realtime tasks. On Mon, Apr 7, 2014 at 10:14 AM, Stacy Cottles <fm3...@gmail.com> wrote: > Eric, I apologize for my ignorance but what is the pru? > > On Sunday, April 6, 2014 6:18:27 PM UTC-5, Eric wrote: >> >> I might be inclined to use the pru for this and just setup the pru as >> escentially a hardware counter. There are likely ways to do so with timers >> and interrupts and such but being more of a hardware guy than software I'm >> inclined to use a more hardware approach and use the pru as a counter that >> gets read every so often. the software for that then is escentially a >> driver that creates /dev/rpm. >> >> Eric >> >> >> On Sun, Apr 6, 2014 at 3:43 PM, Stacy Cottles <fm3...@gmail.com> wrote: >> >>> Thanks Eric for the suggestion. I'll have to figure out the inductive >>> circuit to use. Do I have to use interrupts or is there something better >>> for capturing the signal from the pickup? >>> >>> >>> On Sunday, April 6, 2014 1:51:07 PM UTC-5, Eric wrote: >>> >>>> an inductive pickup around the sparkplug wire should get you a nice >>>> pulse each time the spark plug fires but remember the phases of a 4 stroke >>>> engine (intake - piston down intake valve open, compression - piston up >>>> valves closed, power - piston down valves closed, exhaust - piston up >>>> exhaust valve open). The spark plug only fires every other revolution. >>>> Once you have the pulse from the inductive pickup it should be buffered to >>>> provide a nice square wave pulse of uniform voltage such that it's easy for >>>> the processor to use and not a potential hazard to the processor due to >>>> spurious high voltages (cooking the buffer circuit while in development, >>>> sorta ok.... cooking the processor, well not so much!) >>>> . from there it's just software and the incrementing of a counter with >>>> each pulse. >>>> >>>> >>>> >>>> >>>> On Sun, Apr 6, 2014 at 6:33 AM, Stacy Cottles <fm3...@gmail.com> wrote: >>>> >>>>> I am building a web-controlled lawn-mower. I would like to be able to >>>>> read the RPM off the gas-engine. I would prefer to piggy-back off of the >>>>> spark-plug if possible since it fires faster as the engine spins faster. >>>>> Just started on this but would love suggestions. I have a Beaglebone Black >>>>> running Angstrom and I am using NodeJS to control GPIOs. >>>>> >>>>> -- >>>>> 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...@googlegroups.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 beagleboard+unsubscr...@googlegroups.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 beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
