Author Topic: OCuLink ambiguity  (Read 134 times)

pocock

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OCuLink ambiguity
« on: June 01, 2020, 02:05:08 am »

When I look at the ordering pages on the Raptor site, it offers various OCuLink products:

  • 4x OCuLink PCIe Expander (Gen 3)
  • OCuLink to U.2 Cable

The manual:
https://wiki.raptorcs.com/w/images/e/e3/T2P9D01_users_guide_version_1_0.pdf

includes errata stating that

ER0001
╬╝PCIe connector (J10108) is incorrectly identified as OCuLink (SFF-8621) due to errors that were discovered post-production in IBM OpenPOWER reference designs.  While the physical connector is the same as OCuLink ports, the wiring is different, notably in the presence detect / clocking pins.  As such, while an OCuLink peripheral is unlikely to be damaged by being plugged in to the ╬╝PCIe port, it will not function while attached.


If that is the case, buyers selecting the OCuLink products will not be able to use them - or has the board design been changed somehow to make OCuLink work?
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pocock

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Re: OCuLink ambiguity
« Reply #1 on: June 17, 2020, 06:02:02 am »

From the Thunderbolt 3 thread...

The only thing I can say is that a working OCuLink adapter is listed in the RCSwiki.

but it is odd that the ordering page includes an option to select an OCuLink PCIe Expander but the form doesn't include any of the OCuLink adapters.  When I noticed that, it left me wondering if there is OCuLink support on the motherboard.  It would be no use for somebody to order the expander and motherboard without also ordering one of the OCuLink adapter cards.
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