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AR# 39601

12.x Route - How can I generate an intermediate NCD for analysis before routing completes?


The router can take a long time trying to reduce the timing errors in the design. How can I generate an intermediate NCD before routing completes so that I can analyze the design in Timing Analyzer or FPGA Editor?


You can use the Smart-Preview option to capture a snapshot of the design once it is fully routed but has not yet completed routing due to timing errors.

From Project Navigator:

1. Right click on Place & Route process and select "stop".
2. In the pop-up window, select "Preserve most recent SmartPreview and continue processing"

3. PAR willwrite an intermediate NCD anda timing summary in <project directory>/SmartPreview folder. After capturing the Smart-Preview design, PAR will return torouting in order to improve timing.

From the command line:

1. Wait until the router has completed all connections and reported "o unrouted"
2. Type Control-C
3. Select option 3 to capture a Smart-Preview snapshot of the current routing results
4. Examine the Smart-Preview design and timing report in the SmartPreview directory

Phase 5 : 0 unrouted; (Setup:48694, Hold:0, Component Switching Limit:0) REAL time: 1 mins 23 secs

Ctrl-C interrupt detected.
| Most recent SmartPreview on disk: | test.ncd |
| Fully placed: | YES |
| Fully routed: | YES |
| SmartPreview status: | ready for bitgen |
| Timing score: | 21332 |
| Timing errors: | 73 |
| Number of failing constraints: | 1 |
Option 3 in the menu below will save the SmartPreview design
file and a timing summary in ./SmartPreview.
MENU: Please choose one of the following options:
1. Ignore interrupt and continue processing.
2. Exit program immediately.
3. Preserve most recent SmartPreview and continue (see STATUS above).

Enter choice --> 3

Copying SmartPreview design file: ./SmartPreview/test_21332.ncd
Creating SmartPreview timing report: ./SmartPreview/smartpreview_21332.twr

Phase 6 : 0 unrouted; (Setup:45310, Hold:0, Component Switching Limit:0) REAL time: 1 mins 44 secs


AR# 39601
Date Created 01/25/2011
Last Updated 12/15/2012
Status Active
Type General Article
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