Hi Alex, some guile line that I follow during my debug sessions:
- Are you using a good cable-delay estimation for your cable? (Consider ~5ns/m for classical eth cables) I suggest you to physically measure the delay and place it as Dcable cell in Calnex configuration. - Have you checked about any asymmetry between RX and TX paths? Can you short-circuit your timestamper to check? You need to ask your FPGA and HW experts. - How is the 1PPS driven? Is there any reclocking logic? You need to ask your FPGA-experts. ciao luigi Il giorno gio 8 set 2022 alle ore 13:44 Hamilton Alex < alexzanda...@gmail.com> ha scritto: > Hi: > I got an issue that linuxptp result doesn't match 1PPS measurement. > my board is acting as a slave, the calnex is acting as a master with > reference clock. > after ptp4l runs, result is below, looks pretty good: > > ptp4l[130166.661]: rms 1 max 2 freq -50 +/- 4 delay 9059 +/- > 0 > ptp4l[130167.661]: rms 1 max 1 freq -50 +/- 2 delay 9058 +/- > 0 > ptp4l[130168.662]: rms 1 max 2 freq -52 +/- 3 delay 9058 +/- > 1 > ptp4l[130169.661]: rms 1 max 3 freq -49 +/- 4 delay 9058 +/- > 0 > ptp4l[130170.661]: rms 1 max 2 freq -50 +/- 4 delay 9059 +/- > 0 > ptp4l[130171.662]: rms 1 max 2 freq -49 +/- 3 delay 9058 +/- > 0 > > my board has 1PPS output, I connect it to the master and compared with > reference PPS. > however, the 1pps time error is around 40 NS, which means my board is > ahead of the reference for about 40NS, which doesn't match the result > dumped by ptp4l. > > anyone has met similar issue before? how to debug such issue? > > - > > 1ppsTE = (T1ppsMeasIngress – Dcable) - TRef > > > https://calnexsolutions.atlassian.net/wiki/spaces/KB/pages/71991334/T-BC+Time+Error+Metrics > > Thanks > Alex > > _______________________________________________ > Linuxptp-devel mailing list > Linuxptp-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linuxptp-devel > -- *Luigi 'Comio' Mantellini* My Professional Profile <http://www.linkedin.com/in/comio> *"UNIX is very simple, it just needs a genius to understand its simplicity." [cit.]*
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