...Clock input (from IBUFG,BUFG or DCM));BUFG_inst1 :BUFG...
BUFG_inst1 :BUFGport map (O => clk4,-- Clock buffer outputI => clk3 -- Clock buffer input);我用这个map的时候却总是报错DCM_SP symbol "DCM_SP_inst1" (output signal=clk3) has anequation that uses input pin I0,which no longer has a connected signal....