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Fifo information

Hai all,


I have some doubts about core generated fifos.


Whether it is possible to check a fifo is standard or FWFT by looking the xco file only.


How can I read Full threshold assert value from fifios xco file.


Whether it is possible to simulate core generated fifos in Xilinx Ise simulator



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Registered: ‎08-14-2007

The .xco file is a text document.  You can open it with any text editor.  If you have

a first-word fall-through FIFO, there should be a line like:


CSET performance_options=First_Word_Fall_Through


Programmable full thresholds look like:


CSET full_threshold_assert_value=1023
CSET full_threshold_negate_value=1022

also look at the value of:


CSET programmable_full_type=No_Programmable_Full_Threshold

which in this case shows that the programmable full feature is not enabled.


You can also open the .xco file with Coregen and page through the

customization screens to see all of the settings in a more user-friendly

display.  The best way to do this is to use the option of "recustomize under

original project settings" so you don't see anything that might change

if you were to use the current project settings.


Coregen FIFO's can be simulated with ISIM.  Note that there are two types of

models available for these FIFO's and only the "structural" models are cycle-

accurate.  I have also found that at least for the latest versions of FIFO generator

and Spartan 6, the "behavioral" model does not properly assert the programmable

flags in some circumstances.  In any case it is recommended to use the

structural model if you use Coregen FIFO's.




-- Gabor
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