Stats

  • Locked Locked
  • Replies 7
  • Subscribers 62
  • Views 21326
  • 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

How to synthesize without scan cell replacement

Maso

Hi,

 I synthesize RTL with RTL Compiler.

I have setup below options.

set_attr dft_connect_scan_data_pins_during_mapping ground [find / -design *]
set_attr dft_connect_shift_enable_during_mapping tie_off [find / -design *]
set_attr dft_scan_map_mode preserve [find / -design *]

But when I finished synthesis, I always get my netlist with scan cells replacement.

How can I avoid the scan cells replacement ?

 Thanks a lot.

Parents

  • Maso,

    I think the best way is to simply NOT run "check_dft_rules".  During "check_dft_rules", RC will mark every flop as scannable, or not.  All flops that are scannable will be mapped to scan.  If you don't run check_dft_rules, all flops will be considered non-scan.  I suggest leaving dft_scan_map_mode set to tdrc_pass.

     Another option, I suppose, is to set dft_dont_scan attribute to "true" on all flops.  This would also work, but simply not running check_dft_rules is probably the simplest solution.

     FYI... if you want to prevent RC from using scan flops for non-DFT purposes, you will want to set this attribute:
          set_attr use_scan_seqs_for_non_dft false /

    I am curious, why do you not want to map to scan flops?   Usually this is desired to account for the extra mux delay and extra load on the flop Q pin.

    Brad

     

     

Reply

  • Maso,

    I think the best way is to simply NOT run "check_dft_rules".  During "check_dft_rules", RC will mark every flop as scannable, or not.  All flops that are scannable will be mapped to scan.  If you don't run check_dft_rules, all flops will be considered non-scan.  I suggest leaving dft_scan_map_mode set to tdrc_pass.

     Another option, I suppose, is to set dft_dont_scan attribute to "true" on all flops.  This would also work, but simply not running check_dft_rules is probably the simplest solution.

     FYI... if you want to prevent RC from using scan flops for non-DFT purposes, you will want to set this attribute:
          set_attr use_scan_seqs_for_non_dft false /

    I am curious, why do you not want to map to scan flops?   Usually this is desired to account for the extra mux delay and extra load on the flop Q pin.

    Brad

     

     

Children
No Data

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.