From: Jesse W. <jes...@gm...> - 2007-02-15 19:45:36
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Is this a production model (ie cost sensitive) or prototype/research? If cost isn't a issue I would go with a robostix because the development environment is already there with the gumstix. But I agree. For a 5000Hz sampling rate I would use more hardware. But I'm an armature and often wrong...... On 2/15/07, EXT-McGhehey, Mark J <Mar...@bo...> wrote: > > > Elliot, > I find that to be a very intriguing concept and I have also begun to > persue such an implementation. I am working on a system that requires > sensor sample rates as high as 5000Hz and so far I have not been able to > achieve this with only a single 400xm BT Gumstix. > > I would be very interested in hearing more from you about this and > hopefully maybe I can contribute something also. > > Thanks. > > Mark > > ________________________________ > From: G Elliott [mailto:gel...@gm...] > Sent: Thursday, February 15, 2007 2:36 AM > To: General mailing list for gumstix users. > Subject: Re: [Gumstix-users] Critical Real Time on the gumstix > > > can i offer a different way of going about this? i had a very similar > problem, though i'm only reading at 140hz (but very time critical). > > > my solution was to offload that processing to a pic chip that communicates > via serial. i also offloaded some algorithms onto the pic so that much of > the heavy lifting was done in outside of the gumstix, then the pic would > send relevant data to the gumstix as needed. its cheap, robust, and fast. > > > if you're interested in pursuing this type of solution, i'd be happy to let > you know how i worked it out. > > > > greg.elliott > arts.computation.engineeringuniversity.of.california.irvine > > > > > > > On Feb 13, 2007, at 6:33 AM, Brendan Maguire wrote: > > Hey, > > Still looking for help with the below if anyone has any info? > > >Does anyone have any simple example C code for using the one of the timer > >interrupts? I've been looking around for ages and I'm not getting anywhere > >with this! I'd be very grateful if someone could just post up the code that > >would enable the interrupt to execute a small isr function. > > I also tried changing the HZ value in > /gumstix-buildroot/build_arm_nofpu/linux-2.6.18gum/arch/arm/Kconfig > to 1000 to see if I could make the scheduler swap tasks faster and therefore > run my code often enough but when I compiled the new filesystem and > reflashed the device it still seems to be running with the HZ value of 100. > Heres the output of this program: > > int main() > { > struct sched_param sp; > int periods; > int ms; > long i; > > struct timespec ts; > struct timeval tv; > > ts.tv_sec = 0; > ts.tv_nsec = 10; > > sp.sched_priority = sched_get_priority_max( SCHED_FIFO ) - 1; > > if( sched_setscheduler( 0, SCHED_FIFO, &sp ) == -1 ) > { > printf("Cannot set scheduler\n" ); > return(1); > } > > for(i = 0; i < 10000000; i++) > { > nanosleep(&ts, NULL); > gettimeofday(&tv, NULL); > printf("%d\n", tv.tv_usec); > } > > return(0); > } > > Output: > > 870000 > 880000 > 890000 > 900000 > 910000 > 920000 > 930000 > 940000 > 950000 > 960000 > 970000 > > As can be seen it is still loosing processor time for 10ms at a time. Any > ideas? > > Thanks, > Brendan > > ------------------------------------------------------------------------- > Using Tomcat but need to do more? Need to support web services, security? > Get stuff done quickly with pre-integrated technology to make your job > easier. > Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo > http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642_______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys-and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > > |