Home > Community > Forums > Digital Implementation > About Encounter Warning 'TA-549'

Email

* Required Fields

Recipients email * (separate multiple addresses with commas)

Your name *

Your email *

Message *

Contact Us

* Required Fields
First Name *

Last Name *

Email *

Company / Institution *

Comments: *

 About Encounter Warning 'TA-549' 

Last post Tue, Feb 26 2008 6:55 PM by archive. 2 replies.
Started by archive 26 Feb 2008 06:55 PM. Topic has 2 replies and 1099 views
Page 1 of 1 (3 items)
Sort Posts:
  • Tue, Feb 26 2008 6:55 PM

    • archive
    • Top 75 Contributor
    • Joined on Fri, Jul 4 2008
    • Posts 88
    • Points 4,930
    About Encounter Warning 'TA-549' Reply

    hi All:

    I get the following message when run timing analysis:

    --> WARNING: Pin 'msd_ddr_phy/ddr_sstl/dll_ato_io125/AE' is driven 'ZERO' and
                 'X' simultaneously, preserving 'X.' .
    --> WARNING: Pin 'msd_ddr_phy/ddr_sstl/dll_dto_0_io121/OJ' is driven 'ZERO' and
                 'X' simultaneously, preserving 'X.' .


    Why? Does it relate to constant propagation? where comes the 'X'?


    Originally posted in cdnusers.org by eminemshow
    • Post Points: 0
  • Thu, Mar 27 2008 3:14 PM

    • archive
    • Top 75 Contributor
    • Joined on Fri, Jul 4 2008
    • Posts 88
    • Points 4,930
    RE: About Encounter Warning 'TA-549' Reply

    If there a different drivers on a net, and they are not driving the same signal state (0,1,X) on to the
    net, then system has to resolve which state the signal is in in order to propagate forward.

    The Warning you see indicates that there is such a conflict - in the case between a X (unknown) state and 0 (ZERO)
    state. The timer resolves this "conservatively" by keeping the X. All signals have a state value of X in the timer
    unless some explicit state assertion is made (set_case_analysis), and propagated forward.

    Other tools (PT I think) resolve the above scenario to ZERO rather than X. There is a CTE global to provide a similar
    resolution policy:

    set_global timing_resolve_driver_conflicts {conservative | aggressive}

    default: conservative

    (Note: for some reason this global is not in the current doc set. We'll look into getting that added)


    Originally posted in cdnusers.org by ejm
    • Post Points: 0
  • Thu, Mar 27 2008 7:40 PM

    • archive
    • Top 75 Contributor
    • Joined on Fri, Jul 4 2008
    • Posts 88
    • Points 4,930
    RE: About Encounter Warning 'TA-549' Reply

    Many thanks. EJM!

    If there is a X state, what does this stand for? Does X means '0' or '1'? Or X means 'high resistance state'?


    Originally posted in cdnusers.org by eminemshow
    • Post Points: 0
Page 1 of 1 (3 items)
Sort Posts:
Started by archive at 26 Feb 2008 06:55 PM. Topic has 2 replies.