如何约束DCM的位置

打开PlanAhead，找到dcm器件，手动拖动到理想位置，保存ucf文件。

    You can select using mouse in PACE or PlanAhead.. and then save the .ucf... job done.. But you should be aware of the location of DCMs in the chip.. you can see that in Datasheet

类似：
INST "U_pll_adv" LOC = "PLL_ADV_X0Y1";