Why do I get a java.lang.NullPointerException error when I change the width of my Altera DSP Builder Input block in Simulink?

Description

You will receive an error message similar to the one below when changing the parameters of certain Altera® DSP Builder blocks, including the Input block, if the Simulink® model is using the .SLX format - <filename>.slx.

Error reported by S-function 'sInOut' in <model_name>/Input':
java.lang.NullPointerException at
com.altera.dspbuilder.simulation.Model.getAbsoluteTestbenchPath(Unknown
Source) at come.altera.dspbuilder.simulation.Model.getValidIOFile....

Resolution

To workaround this issue save the Simulink model as an MDL format model - <filename>.mdl.  At this point you should be able to make the parameter changes without the error.

This issue will be fixed in a future release of the DSP Builder / Quartus® II software.