188.8.131.52. Using Incremental Compilation with the Signal Tap Logic Analyzer
The Signal Tap Logic Analyzer uses the incremental compilation flow by default. For all signals that you want to connect to the Signal Tap Logic Analyzer from the post-fit netlist:
- In the Design Partitions window, set the netlist type of the partition that contains the signals to Post-Fit, with a Fitter Preservation Level of Placement and Routing.
- In the Node Finder, use the Signal Tap: post-fitting filter to add the signals of interest to your Signal Tap configuration file.
- If you want to add signals from the pre-synthesis netlist, set the netlist type to Source File and use the Signal Tap: pre-synthesis filter in the Node Finder. Do not use the netlist type Post-Synthesis with the Signal Tap Logic Analyzer.
- Read all incremental compilation guidelines to ensure the proper partitioning of a project.
- To speed up compile time, use only post-fit nodes for partitions specified as preservation-level post-fit.
- Do not mix pre-synthesis and post-fit nodes in any partition. If you must tap pre-synthesis nodes for a particular partition, make all tapped nodes in that partition pre-synthesis nodes and change the netlist type to source in the design partitions window.
Node names can differ between a pre-synthesis netlist and a post-fit netlist. In general, registers and user input signals share common names between the two netlists. During compilation, certain optimizations change the names of combinational signals in your RTL. If the type of node name chosen does not match the netlist type, the compiler may not be able to find the signal to connect to your Signal Tap Logic Analyzer instance for analysis. The compiler issues a critical warning to alert you of this scenario. The signal that is not connected is tied to ground in the Signal Tap data tab.
If you do use incremental compilation flow with the Signal Tap Logic Analyzer and source file changes are necessary, be aware that you may have to remove compiler-generated post-fit net names. Source code changes force the affected partition to go through resynthesis. During synthesis, the compiler cannot find compiler-generated net names from a previous compilation.
Both registered and user-supplied input signals share common node names in the pre-synthesis and post-fit netlist. As a result, using only registered and user-supplied input signals in your .stp limits the changes you need to make to your Signal Tap Logic Analyzer configuration.
You can check the nodes that are connected to each Signal Tap instance using the In-System Debugging compilation reports. These reports list each node name you selected to connect to a Signal Tap instance, the netlist type used for the particular connection, and the actual node name used after compilation. If the incremental compilation flow is not used, the In-System Debugging reports are located in the Analysis & Synthesis folder. If the incremental compilation flow is used, this report is located in the Partition Merge folder.
To verify that your original design was not modified, examine the messages in the Partition Merge section of the Compilation Report.
Unless you make changes to your design partitions that require recompilation, only the Signal Tap design partition is recompiled. If you make subsequent changes to only the .stp, only the Signal Tap design partition must be recompiled, reducing your recompilation time.
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