Stats

  • Locked Locked
  • Replies 2
  • Subscribers 63
  • Views 13363
  • 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

Gate mapping in RC

gchalive

 Hi there.

 Is there any attribute to set in cadence RC which prevents from mapping a function to a different gate implementing a different function.

For example I dont want it to program a nand gate to implement an inverter by tying one of the inputs to 1. 

Thanks

gchalive

  •  Hi gchalive,

     I am curious what your exact requirement. What your describing on combinational cells makes limited sense since ultimately your HDL would have to be excruciatingly detailed to ensure 1:1 correspondance exist to every combo structure in your design. Say

     

    assign a = b || c || d || e && f && !g

    could map to a large number of permutations hence why you let the synthesis tools decide the optimal one

    There are controls in RC for exact mapping of flops and to limit mapping of specific HDL constructs but ultimately the question is why should you need to do any of that. RC will only map an inverter the way you described earlier if it provided a QoR benefit. Otherwise, there is no reason RC would not pick the inverter.

     regards,

    gh-

  • Hi..
     
    I would want RC to retain only few logic gates in my design.
    It may map the rest of the logic optimally. I have found the attribute to set this to happen. It is, set_attribute preserve true <cell_name>
     
    Thanks for your response.
     
    Thanks
    gchalive

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.