Why does the PCI Express example design fail to simulate in the Synopsys VCS simultion tool? - Why does the PCI Express example design fail to simulate in the Synopsys VCS simultion tool? Description Due to a problem in the Quartus ® II Software version 12.1, errors may be seen when simulating the PCI Express Qsys example design using the autogenerated simulation scripts for the Synopsys VCS_MX tools. One of the following errors may be seen: Error-[MPD] Module previously declared The module was previously declared at: "./../..//pcie_de_gen1_x4_ast64_tb/simulation/submodules/altpcietb_bfm_rp_gen2_x8.v", 47 It is redeclared later at: "./../..//pcie_de_gen1_x4_ast64_tb/simulation/submodules/altpcietb_bfm_rp_gen2_x8.v", Error-[URMI] Unresolved modules ./../..//pcie_de_gen1_x4_ast64_tb/simulation/submodules/altpcietb_bfm_top_rp.v, 454 "altpcietb_bfm_log_common bfm_log_common( .dummy_out (bfm_log_common_dummy_out));" Module definition of above instance is not found in the design. Resolution To workaround this problem in the Quartus II Software version 12.1 follow the steps below: Open the generated simulation script <path>/testbench/simulaiton/vcsmx/vcsmx_setup.sh in a text editor Update USER_DEFINED_ELAB_OPTIONS to add in the required library include path: USER_DEFINED_ELAB_OPTIONS="-y ../../<design name>_tb/simulation/submodules/" Open the following file in a text editor: <path>/testbench/<design name>_tb/simulation/submodules/altpcietb_bfm_rp_gen2_x8.v Locate the dupicate module definition by searching for module altpcietb_bfm_log_common and comment out the second instance (Lines 888-1247) Re-run the simulation script ./vcsmx_setup.sh This problem is scheduled to be fixed in a future version of the Quartus II software Custom Fields values: ['novalue'] Troubleshooting novalue False ['novalue'] ['FPGA Dev Tools Quartus II Software'] novalue 12.1 ['Arria® V GT FPGA', 'Arria® V GX FPGA', 'Arria® V GZ FPGA', 'Arria® V ST FPGA', 'Arria® V SX FPGA', 'Cyclone® V GT FPGA', 'Cyclone® V GX FPGA', 'Cyclone® V ST FPGA', 'Cyclone® V SX FPGA', 'Stratix® V GS FPGA', 'Stratix® V GT FPGA', 'Stratix® V GX FPGA'] ['novalue'] ['novalue'] ['novalue']