altera pll应用报错

Error (176554): Can't place  PLL "ch0_pll:ch0_pll_inst|altpll:altpll_component|ch0_pll_altpll:auto_generated|pll1" -- I/O pin ch0_pclk (port type INCLK of the PLL) is assigned to a location which is not connected to port type INCLK of any PLL on the device
各位帮忙看下是什么问题，有点晕，谢谢
个人感觉应该是PLL的输入应该是一些专有的管脚，比如CLKn,CLKp，而不能随便去用,如通用IO或者DPCLK等。