Cyclone V: PCIe x4 + XAUI.

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Cyclone V support FPLL as TX PLL feature.

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Yes, in the "Upcoming Cyclone V Device Features" it is written that

"PMA clock output (fPLL as transmit PLL)" is currently supported.

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Please check for the datasheet what is the MAX frequency the FPLL can support?

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Yes, fPLL Serial Data Range is from 0.611 Gbps to 3.125 Gbps.

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Maybe you can use 1 of the FPLL to create 1.5625GHz Fast clock for XAUI? :p

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The most important question is how to make it? :)

When I am generating XAUI Megacore function I can choose only CMU PLL type.