MentorGraphics ModelSim SE 6.6d error: Fatal: Unexpected signal: 11.

Description

During simulation of a Qsys-generated VHDL design that includes DDR2 or DDR3 external memory cores with ALTMEMPHY, the 64-bit version of Mentor Graphics ModelSim SE 6.6d may issue a fatal error similar to the following:

#**Note: (vsim-3812) Design is being optimized... #**Fatal: Unexpected signal: 11.

Resolution

Use the 32-bit version of Mentor Graphics ModelSim SE 6.6d or use the -novopt option with the vsim command.