Stats

  • Locked Locked
  • Replies 4
  • Subscribers 63
  • Views 15877
  • Members are here 0
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

RTL Compiler: how to get units for load

yongchen

Hi,

I have set units in RC as this way: set_units -time ps -capacitance pF, I just want to read it back for double check. But I failed on command: get_attr units ..... Can anybody tell me the right way to read back current units for time and capacitance? thanks.

  • Hi, You can try printing the units that has been applied in sdc as follows. The default units are in FemtoFarads and Picoseconds in RC. Based on the value being applied, the return value will include multiplier value for FemtoFarads for Capacitance and Picoseconds for time units. puts "[get_attr sdc_load_unit /designs/test_case ] fF puts "[get_attr sdc_time_unit /designs/test_case ] ps For you example (set_units -time ps -capacitance pF) , the return value from RC is rc:> puts "[get_attr sdc_load_unit /designs/test_case ] fF" 1000.0 fF rc:> puts "[get_attr sdc_time_unit /designs/test_case ] ps 1.0 ps Hope this helps.

  • Hi, thanks for your kind reply. I have tried the way you suggested and it works. Thank you very much.

    by the way, I have run "get_attr * * -h" and tried to find attribute for "sdc_time_unit/sdc_load_unit", but found nothing. How can you find these two attributes? Is there any hidden tips? thanks.

     

  • Hi, Yes, these are hidden attributes and hence no documentation is available. If you know the name of attribute, then you can query them in the release builds as well. Regards Jay

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.