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Altera_Forum's avatar
Altera_Forum
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14 years ago

Extension cable for PCIe

Hi,

I have a Arria II GX dev kit and want to use the PCIe interface. I am planning to connect it using an extension cable instead of connecting it directly on the mother board. Any suggestions in finding the extension cables would be of great help.

Also, will there be any timing related issues if I use a long (1m) extension cable?

Thanks,

San

6 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    Internal PCIe interfaces are using a common Refclk architecture, as far as I understand. By specification, the data/clock transport delay delta t1 must not exceed 12 ns (see PCIe Base-Specification V2.0, 4.3.7.2.2. Common Refclk Architecture). Considering various on chip and motherboard wiring delays, a 1 m extension cable can't keep it. I don't know however, if the parameter is critical. Apart from this problem, I'm only aware of short (0.1 - 0.2 m extension cables) available as retail products.

    In addition, you have to keep the attenuation and other signal quality parameters.
  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    I have used PE-FLEX from http://www.adexelec.com - they have 1, 4, 8, and 16 lane versions, in lengths up to 15 inches (~38cm). I think we have ordered even longer 1 lane cables.

    There are more robust solutions that may support longer lengths, but will probably cost more.

    \chuck
  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    For testing my Stratix IV GX development kit from my laptop, I use the following setup:

    1. HP Elitebook laptop with ExpressCard slot.

    2. OneStopSystems ExpressCard-to-PCIe x1 cable

    (the ExpressCard only has a x1 lane in it)

    OSS-PCIe-HIB2-EC-x1

    http://www.onestopsystems.com/pcie_over_cable_z6.php

    3. OSS-PCIe-CBL-x1/x4-2M Two meter x1 to x4 PCIe cable

    http://www.onestopsystems.com/pciex1tox4cable.php

    4. OneStopSystems 3 slot PCIe motherboard

    OSS-PCIe-uATX-BP-2018

    http://www.onestopsystems.com/pcie_atx_bp.php

    The motherboard uses a PLX PEX8533 PCIe bridge. The datasheet is available under NDA from PLX.

    Cheers,

    Dave
  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    And somewhat less robust than the nice OneStopSystems solution, the low budget equivalent would be:

    2. http://www.hwtools.net/adapter/pe3.html PE3 adapter from hwtools.net

    3. the aforementioned PE-FLEX cable from Adec.

    And newegg has resonably priced PCIe cards with expresscard slots, so if you are using a desktop system, you can have a PCIe connection without leaving the cover off the system.