Thanks for all the info. Well, it turns out that the clock chip was the culprit. Although it met the 50 PPM Ethernet frequency stability requirement, it had a LOT of jitter. I replaced it with a $1.98 ECS crystal oscillator (as opposed to the MEMS oscillator, and it Just Worked. I am amazed and very happy.
On Wed, Feb 19, 2020 at 7:23 AM Ross Martin <[email protected]> wrote: > Jean, > > You're right. Getting the pinout wrong on the ethernet connectors > probably leads to false pairing rather than to loss of one wire in the pair. > > Regards, > > Ross > > > On Wed, Feb 19, 2020, 3:09 AM Borsenberger Jean < > [email protected]> 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 < >> [email protected]> 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 <[email protected]> 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 <[email protected]> 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 <[email protected]> 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 "[email protected]" group. >>>>> To unsubscribe from this group and stop receiving emails from it, send >>>>> an email to [email protected]. >>>>> 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 "[email protected]" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to [email protected]. >>>> 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 "[email protected]" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> 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 >> "[email protected]" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> 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 >> "[email protected]" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> 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 " > [email protected]" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CAG4nf70X5qYCp5PhShGFFuEwxuuoDBwE72obaWOVfcCKu9fenw%40mail.gmail.com > <https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CAG4nf70X5qYCp5PhShGFFuEwxuuoDBwE72obaWOVfcCKu9fenw%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "[email protected]" group. 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