Batch Mode Utility to Extract Clock Trees: nClockTree
The Verdi™ Automated Debug System with the nAnalyzer™ Design Analysis module provides full functions for extracting clock trees and qualifying CTS (Clock Tree Synthesis) settings. However, the clock tree extraction has to be processed in the Verdi system with the nAnalyzer module so the debug time may be occupied especially if the gate level netlist is vast.
To reduce the effort of extracting clock trees every time (especially when there aren’t any changes to the design), the Verdi system provides a batch mode utility nClockTree to do the clock tree extraction in batch mode and save the results in a loadable file. With this one-time effort, users can load the extraction results and all settings into the Verdi system with nAnalyzer for further CTS qualification.
The following steps demonstrate how to extract clock trees, save the extracted results as a loadable database (or an Astro format ASCII report), and then load the loadable database into the Verdi system for further qualifications:
1. Execute the nClockTree utility to extract clock trees:
Use the utility nClockTree under <Novas_install>/bin to read the design and generate the clock tree extraction results. SDC and CTS settings can also be imported and converted to nAnalyzer settings, just like importing these settings in the Verdi system with the nAnalyzer module.
a. To extract clock trees and save the results as a loadable database execute the following example:
% nClockTree -f run.f -sdcFile sdc_system.sdc -outputFormat Database -output CTS.db
b. To extract clock trees and save the results as an Astro format file execute the following example:
% nClockTree -f run.f -sdcFile sdc_system.sdc -outputFormat Astro -output CTS.astro
2. Load the extraction results into the Verdi system for further qualification:
The extraction results and settings can be loaded into the Verdi system through the Save As form. The form can be invoked in one of three ways:
a. In nTrace, invoke the File > Load Clock
Tree Data Base command.
b. In nSchema, invoke the File > Load Clock
Tree Data Base command.
c. In the Clock Tree Browser, invoke the File > Load Clock Tree Data Base command.
3. Save the clock tree extraction and settings to a loadable database from within the Verdi system:
You may make modifications or add more settings for the clock trees after qualifying the extracted clock tree, and then save all of these modifications and settings into the database again. In the Clock Tree Browser window, invoke the File > Save Clock Tree > Save Clock Tree Database command and then specify a file name for saving another ASCII file. A <filename>.log will be automatically generated and all CTS settings are stored in this file. The command File > Save Clock Tree > Save as Astro Format is also available in the Clock Tree Browser window for saving the clock tree as an Astro format in the ASCII file.
