UCF文件修改

baobao697841

NET  "DQ[*]"  IOSTANDARD = SSTL2_I;
NET  "DQS[*]" IOSTANDARD = SSTL2_I;
NET "ADD[*]"  IOSTANDARD = SSTL2_I;
NET "RASN"  IOSTANDARD = SSTL2_I;
NET "CASN"  IOSTANDARD = SSTL2_I;
NET  "WEN"  IOSTANDARD = SSTL2_I;
NET  "CSN[*]"  IOSTANDARD = SSTL2_I;
NET  "CLK*"  IOSTANDARD = SSTL2_I;
NET  "CLK*_N"  IOSTANDARD =SSTL2_I;
NET  "RST_N"  IOSTANDARD =SSTL2_I;
NET  "CLK"   IOSTANDARD =SSTL2_I;
NET  "RST_N"       LOC = "A3" ;
NET  "CLK"    LOC = "H12" ;
NET  "CLK2"   LOC = "C19";
NET "CLK2_n"     LOC = "C18";
errorlace:897 - The following IOBs have been locked (LOC constraint) to the I/O bank 0.
   They require a voltage reference supply from the VREF pin(s) within the same I/O bank to be available.
   The following VREF pins are currently locked and can't be used to supply the necessary reference
   IO Standard: Name = SSTL2_I, VREF = 1.25, VCCO = NR, TERM = NONE
   List of locked IOB's:
    rst_n
    clk
   List of occupied VREF Sites:
   VREF site PAD80 is occupied by comp dq<3>
   VREF site PAD68 is occupied by comp dq<1>
请问各位怎么修改呢

baobao697841

修改成LVCOMS的就没有错误了，但是不知道对调试有没有影响呢