Hi John, Another thing to check for is a missing or incorrect timing constraint - Vivado constraints wizard may pick up something (tsu, th, tco).
Best HK On Wed, Feb 19, 2020 at 12:09 PM Borsenberger Jean < jean.borsenber...@obspm.fr> wrote: > Hello > > Incorrect cabling would lead to force to dowgrade giga to fast, or no > connection at all. > With that hi level of CRC, I would first address a connector weakness > (contact not complete), or a lack of shielding in a perturbated area, and > most unlikely false pairing inside the cable ( all pairs are individualy > twisted, an if you mix two pairs...) > Try a cat 7 cable ( thick shielding of each pair, thick shielding of the > whole), and see what happens. > Regards > Jean > Le Mercredi, Février 19, 2020 03:33 CET, Ross Martin <ross.mar...@ieee.org> > a écrit: > > > Hi John, > > I'll throw out a possibility. Perhaps the cabling isn't correct and > you're only getting connectivity on one of the two wires in the > differential pair. This would work *sometimes*, which is about what you're > seeing. > > This might happen if you wired your own cables or connectors and laid them > out logically. Cat5 connectors have an unusual pinout that's not exactly > logical. (At least not logical to me.) > > Regards, > > Ross > > On Tue, Feb 18, 2020, 5:47 PM John Ford <jmfor...@gmail.com> wrote: > >> >> >> I did some more testing, and I wanted to share the results. I have done >> reverse loopback testing, sending the packets from the host to the PHY, >> where it loops back inside the PHY, and is returned to the host. This >> shows packet loss on the order of the total packets being lost. So this >> bit of information leads me back to the analog side of things. Power >> supply? oscillator? PCB layout? Our board house did 100 ohm >> differential, and tested it, and it is better than 10%. The traces in the >> pairs are matched to a couple of mils. Here's a drawing of the testing >> that's been done first the digital and analog forwarded loopback, then the >> reverse loopback. >> >> >> >> On Fri, Feb 14, 2020 at 12:52 AM Henno Kriel <he...@ska.ac.za> wrote: >> >>> Hi John, >>> >>> I have a few questions / remarks / suggestions: >>> >>> Do you observer CRC errors in both directions or is it only from FPGA to >>> PC? >>> >>> In RGMII, the TX and RX clocks are not synced, but in loopback mode it >>> is, which might point to a metastability issue when you connect to the PC. >>> >>> Is the PCB a custom board or a DEV-KIT? The length matching of the >>> traces is important, but the TX clock skew to the PHY is also important, >>> since DDR is used. >>> >>> Best, >>> HK >>> >>> On Thu, Feb 13, 2020 at 11:50 PM John Ford <jmfor...@gmail.com> wrote: >>> >>>> Hi all. >>>> >>>> I'm designing an FPGA based instrument control system with a gigabit >>>> Ethernet port. It should be easy to make this work, but alas, it's giving >>>> me fits. >>>> >>>> I have a Xilinx Artix-7 FPGA on the board, driving a TI PHY using the >>>> RGMII interface from the Xilinx tri-mode Ethernet MAC core. It mostly >>>> works, but not completely reliably. >>>> >>>> If I setup the PHY in analog loopback mode, which loops the packets >>>> back to the FPGA, I can run packets at full line rate all day with no >>>> errors. So I'm somewhat convinced that the RGMII link is good between the >>>> FPGA and the PHY. >>>> >>>> If I link the board up to a computer (I've tried a couple different >>>> ones,) I get ~5 to 10% of the packets being received with CRC errors. >>>> >>>> Is there anyone on the list that's designed Gigabit Ethernet hardware >>>> that could give me a hand with this? Any ideas that jump out? I've run >>>> our of ideas. >>>> >>>> Thanks for any advice. If you are or know a good Gigabit Ethernet guru >>>> for hire, let me know! >>>> >>>> John >>>> >>>> >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "casper@lists.berkeley.edu" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to casper+unsubscr...@lists.berkeley.edu. >>>> To view this discussion on the web visit >>>> https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CABmH8B-suUrcdbRYvUpCqF5NuqSE8mboYxFcGj0Mv%3DGMjDoVcQ%40mail.gmail.com >>>> <https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CABmH8B-suUrcdbRYvUpCqF5NuqSE8mboYxFcGj0Mv%3DGMjDoVcQ%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>> . >>> >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "casper@lists.berkeley.edu" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to casper+unsubscr...@lists.berkeley.edu. >>> To view this discussion on the web visit >>> https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CAOjx93idJY1qjbN7HNcJuwPeTz5uFz5%3Dr64eaG3cnyBdd6DU1w%40mail.gmail.com >>> <https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CAOjx93idJY1qjbN7HNcJuwPeTz5uFz5%3Dr64eaG3cnyBdd6DU1w%40mail.gmail.com?utm_medium=email&utm_source=footer> >>> . >> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "casper@lists.berkeley.edu" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to casper+unsubscr...@lists.berkeley.edu. >> To view this discussion on the web visit >> https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CABmH8B9%2BnfqPmG-zsjj%2BPTuz5PHD3ZqnjGytUP6N%2BYRZOktvig%40mail.gmail.com >> <https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CABmH8B9%2BnfqPmG-zsjj%2BPTuz5PHD3ZqnjGytUP6N%2BYRZOktvig%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . > > > -- > You received this message because you are subscribed to the Google Groups " > casper@lists.berkeley.edu" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to casper+unsubscr...@lists.berkeley.edu. > To view this discussion on the web visit > https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CAG4nf73E7ObLJ_khOL_sD8xVK_SEy%3D2ETD7KEuCYXBp-To5WVA%40mail.gmail.com > <https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CAG4nf73E7ObLJ_khOL_sD8xVK_SEy%3D2ETD7KEuCYXBp-To5WVA%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > > > > > > > -- > You received this message because you are subscribed to the Google Groups " > casper@lists.berkeley.edu" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to casper+unsubscr...@lists.berkeley.edu. > To view this discussion on the web visit > https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/354-5e4d0980-89-639bf200%40266659316 > <https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/354-5e4d0980-89-639bf200%40266659316?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "casper@lists.berkeley.edu" group. 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