From: <sun19920...@gmail.com> Reply-To: "beagleboard@googlegroups.com" <beagleboard@googlegroups.com> Date: Thursday, July 17, 2014 at 9:10 AM To: "beagleboard@googlegroups.com" <beagleboard@googlegroups.com> Subject: Re: [beagleboard] inaccuracy issue of clock_nanosleep() with Debian
> 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.. You might find this helpful: http://processors.wiki.ti.com/index.php/TI81XX_PSP_Ethernet_Switch_User_Guid e#IEEE_1588.2F802.1AS_PTP_Support Regards, John > > > 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, <sun19...@gmail.com <javascript:> > 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 beagleboard...@googlegroups.com <javascript:> . >>> 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 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.
