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uni-directional routing with EDI

Agustino

Hi all, 

I am wondering how to force EDI router to strictly use the uni-directional routing only?

 Although the routing directions are already defined in the LEF file, the router still create jogs, staircase line... I looked though the manuals (EDI, nanoroute...), but cannot figure it out. 

I am very appreciated if anyone could help me. Thanks a lot. 

  • What's your objection to jogs / staircase routing ?

    If you can get your initial preCTS trial route relatively straight,  optDesign and routeDesign will naturally follow.

    The only time I have EVER needed to remove trialroute staircase is for wide bus routing during top level assembly.
    Imagine one main channel, nets  A[0:4096]  point to 4x multi-point in a crossbar with B[0:4096]  point to 4x multi-point.
    All 8192 source pins on one one side of the channel and all 32768 sink pins on the other side.
    preCTS trialroute sees this 1:4 sink to source ratio and will naturally tend to "hug" the sink side.
    optDesign -preCTS max cap, tran and distance, buffer insert routine then completely botches it up the channel route-ability .

    The solution was to try and get a nice inital planar river route with net A on M3vert, M4horz and B on M5vert. M4horz.
    I was able to accomplish this by guiding the trial route with temporary preplaced routing targets.
    After optDesign -preCTS the routing targets were removed and the flow continues normally..
    routing target = addInst -cell buf -inst A_4096i ; attachTerm A_4096i ip A_4096 ; placeInstance A_4096i x y -fixed ;

    This was in 1998, now there are probably much better ways to accomplish the same thing  ie busGuide.

    Again the questions remain. What's your objection to jogs / staircase routing ?  What specifically are you trying to accomplish ?

    Shawn

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