DDR2 High Performance Controller multidriver error

Dear All,

I am finding below compilation error in DDR2 memory controller.

I am using stratix III device.

Error: Illegal connection found on I/O input buffer primitive DDR_2_top:dut|DDR_2:R_2_inst|DDR_2_controller_phy:R_2_controller_phy_inst|DDR_2_phy:R_2_phy_inst|DDR_2_phy_alt_mem_phy:R_2_phy_alt_mem_phy_inst|DDR_2_phy_alt_mem_phy_clk_reset:clk|gen_mimic_diff_ibuf.fb_clk_ibuf. Source IO FATEC_DDR_2_top:dut|DDR_2:R_2_inst|DDR_2_controller_phy:R_2_controller_phy_inst|DDR_2_phy:R_2_phy_inst|DDR_2_phy_alt_mem_phy:R_2_phy_alt_mem_phy_inst|DDR_2_phy_alt_mem_phy_clk_reset:clk|DDR_CLK_OUT[0].mem_clk_obuf~0 also drives out to other destination than the buffer.

Any idea about the error?

Best Regards,

Cheevu