我在调试DCM时出现如下错误：

• [NgdBuild 770] IBUFGDS 'ibufgds_1' and BUFG 'clkout1_buf' on net 'CLK_N' are lined up in series. Buffers of the same direction cannot be placed in series.
• NgdBuild 924] input pad net 'CLK_N' is driving non-buffer primitives:   pin O on block dcm/clkout1_buf with type BUFG

• [NgdBuild 770] IBUFGDS 'ibufgds_1' and BUFG 'clkout2_buf' on net 'CLK_P' are lined up in series. Buffers of the same direction cannot be placed in series.

• [NgdBuild 924] input pad net 'CLK_P' is driving non-buffer primitives:   pin O on block dcm/clkout2_buf with type BUFG

源码：

dcm  dcm(  .CLK_IN1(CLK),

                   .CLK_OUT1( CLK_N),

                   .CLK_OUT2(CLK_P),  

                   .RESET(!RESET)

 );

使用DCM截图：

 改怎么解决呢？