# Pastebin Nzx47rR5
clk100 = Signal()
pcie_pads = platform.request("pcie_x1")
self.specials += Instance("IBUFDS_GTE4",
   p_REFCLK_HROW_CK_SEL = 0,
   i_CEB = 0,
   i_I   = pcie_pads.clk_p,
   i_IB  = pcie_pads.clk_n,
   o_O   = clk100)