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Problem with un-mapped elements

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Hi,
I am trying to run Conformal on RTL vs gate-level netlist. I have noticed that synthesis removed a FF in netlist due to that fact that its D input has been tied to 0. Howver while flattening the netlist the FF is not removed and is reported as unmapped element. As a result some comapre points fail due to the fact that this FF is in the logic cone.
By looking at schematic of golden netlist and tracing back the D input of the FF it looks like this pin is connected to other elementes named DC which shows as connection due to constraint. How can I identify which is the offendign constraitn that originated the problem. report_pin_constraint and report_dynamic_constraint command do no report any constraint.

Thanks
Maurizio Spadari  
Principal Design Engineer
NemeriX SA


Originally posted in cdnusers.org by maurizios
Parents

  • I am having a similar problem. In the RTL I have an 8 bit counter, but the logic never counts up beyond 16, so bits 5, 6, and 7 are removed during synthesis. For some reason, conformal will not remove bits 5, 6, and 7 when it reads in the RTL.

    I've tried 'set flatten model -all_seq_merge', but still when I run 'unmapped points -notmapped' it still reports these as unmapped. I've used '-nokeep_unreach' when reading the design, but it still keeps bits 6, and 7 around. How do I get conformal to do the same optimization that the synthesis tool performed?

    I've tried what is suggested above, but I get a ton of mismatches (don't know why yet). Is there something I can do?

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  • I am having a similar problem. In the RTL I have an 8 bit counter, but the logic never counts up beyond 16, so bits 5, 6, and 7 are removed during synthesis. For some reason, conformal will not remove bits 5, 6, and 7 when it reads in the RTL.

    I've tried 'set flatten model -all_seq_merge', but still when I run 'unmapped points -notmapped' it still reports these as unmapped. I've used '-nokeep_unreach' when reading the design, but it still keeps bits 6, and 7 around. How do I get conformal to do the same optimization that the synthesis tool performed?

    I've tried what is suggested above, but I get a ton of mismatches (don't know why yet). Is there something I can do?

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