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Altera_Forum's avatar
Altera_Forum
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7 years ago

Cyclone 10LP PCI clamp diode before configuration complete

Hello,

I've searched through the Cyclone 10 LP documentation and the forum and can't find out what the enable/disable state of the PCI clamp diodes is after power up and before configuration is complete.

Are the PCI clamp diodes enabled on device power up before FPGA configuration is complete?

Thanks, Chris

1 Reply

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    7 years ago

    I agree that the PCI clamp POR state is apparently not mentioned anywhere in the device handbook or data sheet.

    Reading that PCI clamp "should" or "must" be enabled for certain IO standards suggests that it's not enabled before user mode configuration takes effect. The same behavior is known with any other Altera FPGA providing PCI clamp diodes. In other words, they can't protect the FPGA against external signals already present during configuration phase.