Why does Nios® V processor system simulation fail with no print-out message and multiple “x” values along the processor’s signals? - Why does Nios® V processor system simulation fail with no print-out message and multiple “x” values along the processor’s signals? Description This problem may be seen in the Synopsys* VCS* and VCS* MX simulators when simulating the Nios® V processor system generated from Intel® Quartus® Prime Pro Edition Software version 23.1 to 23.4, or Intel® Quartus® Prime Standard Edition Software version 23.1std This is due to the X-propagation support in the simulators. Resolution To workaround this problem, follow these steps : Switch off the X-propagation feature on the processor core, Generate testbench system from the Platform Designer. Navigate into the Synopsys* simulator directory. $ cd <Project>/sys_tb/sys_tb/sim/synopsys Append - xprop=xpropconfig into the shell script in the vcs or vcsmx folder. For example: USER_DEFINED_ELAB_OPTIONS=”-xprop=xpropconfig” Create a file named xpropconfig in the vcs or vcsmx folder (beside the shell script). Copy the following text into xpropconfig, and change the processor entity name. tree {<Nios V processor HDL entity name>} {xpropOff}; Run the simulator . This problem is currently scheduled to be resolved in Intel® Quartus® Prime Pro Edition Software version 24.1 and later. Custom Fields values: ['novalue'] Troubleshooting 13011291749 False ['novalue'] ['FPGA Dev Tools Quartus® Prime Software Standard'] 24.1 23.1 ['Programmable Logic Devices'] ['Simulation Development Tools'] ['novalue'] ['novalue']