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fgfasfafgfdhagdszfea's avatar
fgfasfafgfdhagdszfea
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4 years ago
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Can I apply REFCLK to the FPGA while powered down?

I have a situation where it is possible that the PCIe system could be powered-up while the board with the FPGA could be completely powered-down. The board with the FPGA doesn't share any of the power...
  • skbeh's avatar
    skbeh
    4 years ago

    Hi

    Based on PCIe specification, REFCLK usually comes from rootport CPU via pcie edge connector, users have no control on the CPU side to turn-on/turn-off the REFCLK supply, this is a common scenario, it is okay to continue apply the REFCLK to the FPGA when it is completely unpowered. Similar to the Rx pins, it can be drive while unpowered.


skbeh's avatar
skbeh
Icon for Contributor rankContributor
4 years ago

Hi

Based on PCIe specification, REFCLK usually comes from rootport CPU via pcie edge connector, users have no control on the CPU side to turn-on/turn-off the REFCLK supply, this is a common scenario, it is okay to continue apply the REFCLK to the FPGA when it is completely unpowered. Similar to the Rx pins, it can be drive while unpowered.


  • fgfasfafgfdhagdszfea's avatar
    fgfasfafgfdhagdszfea
    Icon for New Contributor rankNew Contributor
    4 years ago

    Thanks for that information, this will be very helpful for the design.

    Is this information documented somewhere, if so, where is it? Or does it just require inside knowledge?