sedsm ctgen hierarchy problem

Discussion in 'Cadence' started by Eric, May 1, 2005.

  1. Eric

    Eric Guest

    Hello,

    We've been trying to improve our clock tree generation since it bit us
    on
    our last tapeout and limited our clock speed. We're to the point now
    where
    we have primetime/syn2tlf generate a .tlf for our macro blocks. At the
    top
    level, we need to specify the insertion delays for the clock tree in
    each
    macro block so it can balanace from the top level clk root to macro
    block gates.
    information into the tlf. primetime doesn't appear to want to do that.
    It's writing out 0's for the clk tree delays. The second method is to
    specify each block's clock's min and max insertion delay in the ctgen

    constraints file. The same place you specifiy the top level clock tree
    requirements. These are mutually exclusive options according to the
    manuals.

    When I try to do this second option, ctgen then croaks trying to read
    the
    (unchanged) tlfs. I get:

    #---{22:33:43 * clockRoute : Extract Lpin insertion delay: begin}
    #---{22:33:44 tcuWarning: Incompatible format in ctlf library
    '/wims/apr/tlf/dsp.tlf'.}
    #---{22:33:44 Reading timing library "/wims/apr/tlf/dsp.tlf" ...}
    #---{22:33:44 *ERROR* Unable to read timing library file
    /wims/apr/tlf/dsp.tlf.}
    #---{22:33:44 * clockRoute : Extract Lpin insertion delay: end }

    I have no problems running ctgen with no insertion delay commands in
    either
    the tlfs or ctgen constraints files.

    So then I tried manually adding Insertion_Delay() statements into the
    tlfs
    with or without the set_insertion_delays statements in the ctgen
    constraints. I get the same error either way. I'm following syntax
    exactly
    as it is in the cadence ctgen and tlf manuals.

    We're using cadence-dsme-5.4 and a combination of version 3.1 tlfs for

    macros and 4.1 tlfs for std cells/memories.

    Any help would be greatly appreciated.
    Eric
     
    Eric, May 1, 2005
    #1
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