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AR# 62176

FIFO Generator v12.0 - Too many simulation warnings are generated from FIFO generator behavioral models during simulation. How safe is it to ignore these warnings?


When running behavioral simulation on the FIFO Generator, an excessive amount of warnings are being generated.  

Below is an example:

** Warning: (vsim-8684) No drivers exist on out port /fifo_generator_1p_tb/fifo_generator_1p_exdes_inst/fifo_generator_1p_inst/top_inst/U0/<protected>/<protected>/<protected>/<protected>/<protected>/<protected>/<protected>/<protected>, and its initial value is not used.
# Therefore, simulation behavior may occur that is not in compliance with
# the VHDL standard as the initial values come from the base signal /fifo_generator_1p_tb/fifo_generator_1p_exdes_inst/fifo_generator_1p_inst/top_inst/U0/<protected>/<protected>/<protected>/<protected>/<protected>/<protected>.

These warnings can get multiplied when the design has multiple instances of the FIFO Generator. 

Is there a way to stop these warnings from being generated?  

Is it safe to ignore them?


This is a known issue with FIFO Generator simulation models, and it is scheduled to be fixed in 2015.1 release.

If you observe this type of warning during simulation, it can be safely ignored.

AR# 62176
Date Created 09/25/2014
Last Updated 01/19/2015
Status Active
Type General Article
  • FIFO Generator