You also might find accessing the timers from PRU is more accurate
On Fri, Jul 18, 2014 at 12:10 AM, <[email protected]> wrote: > Hello, John, > Excuse me, may I ask that PRU can be used beyond linux system clock? > Because I need to synchronize my BBB with ourter PTP(precision time > protocol) message , if PRU using its clock, then the BBB will become > asynchronized device.. > > Thanks. > > > > > > John Stampfl於 2014年7月17日星期四UTC+8下午11時02分32秒寫道： >> >> Try the "cycle counter" in the pru. >> >> look in the pru section of the forum >> >> >> On Thu, Jul 17, 2014 at 10:35 PM, <[email protected]> wrote: >> >>> I use BeagleboneBlack with Debian, kernel v3.15, and I want to implement >>> an accurate timer on my BBB. >>> I use clock_nanosleep() to wait for 1 second. However, it always turns >>> to be 1 second and 100~120 microsecond delay. (I measured clock_nanosleep() >>> between clock_gettime() and with oscilloscope.) >>> >>> I also run linuxPTP (a software that adjusts system clock, >>> CLOCK_REALTIME, to synchronize linux system with PTP.) to synchronize my >>> BBB. >>> >>> I have no idea how to improve it, should I change linux to real-time >>> linux? (Xenomai or RobertCNelson's patch for linux) >>> or is there another way (such as software, codes, etc) to get more >>> accuracy timer? (under 1us delay.) >>> >>> 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. >>> >> >> >> >> -- >> John Stampfl >> > -- > 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. > -- John Stampfl -- 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.
