top_level.ucf

Clock data recovery .........good example

NET clk PERIOD = 6.5 ns;


INST "CLK_P" LOC = J16;
INST "CLK_N" LOC = J17;

INST "DTE(0)" LOC = K18;
INST "CKE(0)" LOC = AF19;
INST "DTE(1)" LOC = AH15;
INST "CKE(1)" LOC = AG15;

NET "CLK_P" IOSTANDARD = "DIFF_SSTL2_I_DCI";
NET "CLK_N" IOSTANDARD = "DIFF_SSTL2_I_DCI";

#NET "CLK_P" IOSTANDARD = "LVDS_25";
#NET "CLK_N" IOSTANDARD = "LVDS_25";
NET "DTE(0)" IOSTANDARD = "LVCMOS25";
NET "CKE(0)" IOSTANDARD = "LVCMOS25";
NET "DTE(1)" IOSTANDARD = "LVCMOS25";
NET "CKE(1)" IOSTANDARD = "LVCMOS25";