DCM问题

我使用DCM管理时钟，产生时钟后想用planAhead。报错如下：
ERROR: [HDL-25] Module <DCM> does not have a port named <CLK_IN1>. [F:\WorkPlace_Spartan6\Gsmatt_4point_Sram2\Gsmatt\main\main.v:65]
ERROR: [HDL-25] Module <DCM> does not have a port named <CLK_OUT1>. [F:\WorkPlace_Spartan6\Gsmatt_4point_Sram2\Gsmatt\main\main.v:67]
ERROR: [HDL-25] Module <DCM> does not have a port named <CLK_OUT2>. [F:\WorkPlace_Spartan6\Gsmatt_4point_Sram2\Gsmatt\main\main.v:68]