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</o:shapelayout></xml><![endif]--></head><body lang=FR link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Yeah, hardware limits to 1.5ns if we take in account the max frequency of the cortex. (That was the more or less 1ns =) )<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>De :</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Rehab Massoud [mailto:rehab.massoud@gmail.com] <br><b>Envoyé :</b> mardi 27 mars 2018 13:49<br><b>À :</b> BRIARD Sebastien; rtems-users@rtems.org<br><b>Objet :</b> Re: Interrupt latency in RTEMS (Zedboard)<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p>Hi, the smaller theoretical delay accuracy you can measure (without adding to an ASIC cascaded FF) is one clock cycle. I think the maximum frequency that could be achieved on zedboard is not more than 800 MHz, and the maximum Zync's Cortex freq per Zedboard's datasheet is 667 MHz, which means you can't achieve 1 nanosecond accuracy even with hardware measurements, right?<o:p></o:p></p><div><p class=MsoNormal>On Mar 27, 2018 13:30, "BRIARD Sebastien" <<a href="mailto:sebastien.briard@thalesaleniaspace.com">sebastien.briard@thalesaleniaspace.com</a>> wrote:<o:p></o:p></p><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-family:"Arial","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-family:"Arial","sans-serif";color:#1F497D'> </span><o:p></o:p></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>De :</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> BRIARD Sebastien <br><b>Envoyé :</b> mardi 27 mars 2018 11:42<br><b>À :</b> '<a href="mailto:users@rtems.org" target="_blank">users@rtems.org</a>'<br><b>Objet :</b> Interrupt latency in RTEMS (Zedboard)</span><o:p></o:p></p></div></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-family:"Arial","sans-serif"'>Hi,</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-family:"Arial","sans-serif"'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;margin-bottom:12.0pt'><span lang=EN-US style='font-family:"Arial","sans-serif"'>I was trying to measure the interrupt latency in RTEMS with a Xilinx Zynq Zedboard (cortex A9).<br>I modified the c file in classic_signal example to measure time in the main loop and right after entering the handler. <br>That might seem artificial but well, it gives me a value with a relatively simple code.<br><br>I used this code for 100, 10000, and one million ticks per second. I am trying to understand how the measure can quite equal with 100 ticks per second and a million.<br>(I obtained values between 500ns and 1000ns).<br>Is there another timer that is used for interrupt processing ?<br><br>A subsequent question, is it possible to use a larger value than a tick per microsecond ? Maybe I am confusing a little between frequency and tick clock in RTEMS but I would like to run test with more or less a tick per nanosecond.</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span lang=EN-US style='font-family:"Arial","sans-serif"'>Thank you,<br>Sébastien.</span><o:p></o:p></p></div></div><p class=MsoNormal><br>_______________________________________________<br>users mailing list<br><a href="mailto:users@rtems.org">users@rtems.org</a><br><a href="http://lists.rtems.org/mailman/listinfo/users" target="_blank">http://lists.rtems.org/mailman/listinfo/users</a><o:p></o:p></p></div></div></body></html>