Viewing Implementation Results

As mentioned earlier, the Foundation Project Manager maintains control over all of your design implementation versions and revisions. You can directly view and analyze these implementations from the Project Manager.

1. Click the Versions tab on the left-hand side of the Project Manager. You should see a hierarchical display of the implementation you just ran. The revision that is most current is displayed in bold.
   
   

   Figure 7.7 Versions Tab (Schematic Design)

   Figure 7.8 Versions Tab (HDL Design)

2. With the current revision selected, click the Reports tab in the right-hand side of the Project Manager. The Reports tab displays reports and logs for the selected revision of the design.
   
   
3. Double click the report entitled Implementation Report Files. This displays the Xilinx Report Browser, which contains all of the implementation reports. You have the option to browse through any of these reports at this time.
   
   
4. From within the Xilinx Report Browser, double click the Logic Level Timing Report. Inspect this report to find the maximum system frequency specified. Remember this frequency.
   
   
5. Again, from within the Xilinx Report Browser, double click the Post-Layout Timing Report. Inspect this report to find what the maximum frequency is. Compare this with the delay you found in the Logic Level Timing Report.
   
   The difference in the two reports' delays can be accounted for by the actual routing delays. The routing delays which are assumed in the Logic Level Timing Report are best-case, which is why they are generally smaller than the actual delays after placement and routing. Logic Level timing is useful because it gives you a preliminary look at how realistic your timing goals are, given the design's current mapped state.
   
   A rough guideline (known as the 50/50 rule) is that the logical block delays in any particular path will make up about 50% of the total path delay once the design is routed. This is, of course, just a guideline, and designs vary from case to case. But, this gives you some estimate to determine whether the design's timing is even close to your goals before the design is completely placed and routed.
   
   
6. After you have perused the timing reports, close the reports and close the Report Browser.
   
   
7. Return to the Flow tab on the right-hand side of the Project Manager by clicking on it.