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Schematic terminals location and position for automated routing.

KishanVNs

Hi,

 I am trying to create a testchip schematic from a inputfile. But i am facing a small problem.

i.e when i am trying to find the loaction of the terminals whether they are  top , bottom, left , right .. some times it is working . but some times it is giving nil. which i don't understand at all. Instead of beating around the bush i am trying to find an alternate solution.

 Here is the sample code that i am trying to creat for a single instance.

 /**

SchConnectivity("Marvel8_testchips" "SingleCell" "padlib_m6p50derclrev18" "PGB_CSEA_CMGPxA_DxAA_BxL")

**/

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; Procedure 1 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
procedure( SchConnectivity(templibName tempcellName sourcelibName sourcecellName "tt")
  let( (masterId x y cvId instTermBbox instTermBboxInCv
        instTermLLX instTermLLY instTermURX instTermURY
        wireOriginX wireOriginY wireSpace wireWidth wireLength
        deltaX deltaY wireLabel wireOrientation wireJustification
        wireEndX wireEndY termWire Loc_x Loc_y Inst_num  cells  direction
        accessdirection 
  )

;; Opening the Created Cell View ;;

cvSinglecell = dbOpenCellViewByType(templibName tempcellName "schematic" "" "a")
geOpen(    ?lib   "Marvel8_testchips"
        ?cell  "SingleCell"
        ?view  "schematic"
        ?mode  "a"
        )

/*************************************************************************
; symbolId = dbOpenCellViewByType( "ifxbasic" "c_term" "symbol" "" 'r )
; instId = schCreateInst( cvSinglecell  symbolId "I23" -10:5 "R0" )
*************************************************************************/

;; Deleting all the content in the present Cell View
schSelectAllFig( cvSinglecell )
schHiDelete()

Loc_x = 0
Loc_y = 0

cells = 1000
Inst_num = sprintf(nil "IN%d" cells)
symbolId2 = dbOpenCellViewByType( sourcelibName sourcecellName "symbol" "" 'r )
instId2 = schCreateInst( cvSinglecell  symbolId2  Inst_num   Loc_x:Loc_y "R0" )
dbClose(symbolId2)
dbSave(cvSinglecell)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

    x=1
    y=1
    wireSpace=0.0625
    wireWidth=0
    wireLength=0.6
    cterm_num = 0

Instance_BBox = cvSinglecell~>instances~>bBox
println(Instance_BBox )
foreach( inst cvSinglecell~>instances
      printf( "Instance : %s\n" inst~>name )
      ; Print all the Instance terminals for each instance found
      ; in the CV.
      foreach( instTerm inst~>instTerms
          ; For each instance terminal, i.e D-S-B-G, get the bbox
          ; of the  terminal's little square then use dbTransformBBox
          ; to transform the pin bbox to the cellview
          instTermBbox=car(instTerm~>term~>pins~>fig~>bBox)
          instTermBboxInCv=dbTransformBBox(instTermBbox
                           inst~>transform)
          printf( " Instance Terminal= %s : absBbox=%L :
                  relBbox=%L\n" instTerm~>name
          instTermBbox instTermBboxInCv)
          ; get the X/Y coordinates from the BBOX
          instTermLLX=xCoord(lowerLeft(instTermBboxInCv))
          instTermLLY=yCoord(lowerLeft(instTermBboxInCv))
          instTermURX=xCoord(upperRight(instTermBboxInCv))
          instTermURY=yCoord(upperRight(instTermBboxInCv))
          wireOriginX=(instTermLLX+instTermURX)/2
          wireOriginY=(instTermLLY+instTermURY)/2
       
    ;; Reading the lable

direction =    instTerm~>term~>pins~>accessDir
    accessdirection = caar(direction)
     println(accessdirection)

        case(lowerCase(accessdirection)
            ("top"
              deltaX=0
              deltaY=wireLength
              wireLabel="Drain"
              wireOrientation="R270"
              wireJustification="lowerRight"
            )
            ("bottom"
              deltaX=0
              deltaY=-wireLength
              wireLabel="Source"
              wireOrientation="R90"
              wireJustification="lowerLeft"
            )
            ("right"
              deltaX=wireLength
              deltaY=0
              wireLabel="Bulk"
              wireOrientation="R180"
              wireJustification="lowerRight"
            )
            ("left"
              deltaX=-wireLength
              deltaY=0
              wireLabel="Gate"
              wireOrientation="R0"
              wireJustification="lowerLeft"
            )
            ("nil"
              printf("cannot access direction !!! \n")
            )
          )

        wireEndX=wireOriginX+deltaX
        wireEndY=wireOriginY+deltaY

        ; Create the wire
          termWire=schCreateWire(cvSinglecell "draw" "full"
          list(wireOriginX:wireOriginY wireEndX:wireEndY)
          wireSpace wireSpace wireWidth)
        ; Create the Label
        schCreateWireLabel(cvSinglecell car(termWire)
                             wireEndX:wireEndY wireLabel
                              wireJustification wireOrientation
                              "fixed"  wireSpace nil)

        ; Create the c_term
        cterm_num = cterm_num  +1
        ctermInst_num = sprintf(nil "IN%d" cterm_num)
        ctermid = dbOpenCellViewByType( "ifxbasic" "c_term" "symbol" "" 'r )
        ctermID2 = schCreateInst( cvSinglecell  ctermid   ctermInst_num  wireEndX:wireEndY wireOrientation )
        dbClose(ctermid)

       
        ) ; foreach
    ) ; foreach

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
dbSave(cvSinglecell)
dbClose(cvSinglecell)
)
)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; END OF Procedure 1 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 

 If you see the above script ther is a line

 

direction =    instTerm~>term~>pins~>accessDir

 

from where i get which side the terminal is located.

But it doesn't work for every thing. Please let me know if you know any other way.

 

With Regards

Kishan VNs

  • Andrew Beckett

    I'd say it's fairly unusual for symbol pins to have the accessDir attribute set. I just looked at a handful of symbols, and the access direction is not set. It was originally intended that this attribute was used for layout pins, to tell routers which direction(s) to approach them from. It can actually be a list of up to four strings, "left" "right" "bottom" and "top" - in your case you're just looking at the first access direction in the list. If no access direction is set, then it will be nil, as you're finding.

    Usually when writing code to route symbols, you look at the position of the centre of the pin figure, and see which edge it is nearest to - often looking at the "instance" box (the "selection box") on the symbol to decide which edge is nearest.

    Here's a snippet of code I've used tor that - given a point, and a bBox - probably the location of the instance box:

        /***************************************************************
    *                                                              *
    *                   (getClosestEdge xy bBox)                   *
    *                                                              *
    *  INTERNAL function to return one of the symbols left, right  *
    *   bottom or top to indicate whether the specified point is   *
    *  closest to which edge - given a bBox of the symbol - prior  *
    *  to adding pins or labels. Helpful to determine orientation  *
    *                       of labels, etc.                        *
    *                                                              *
    ***************************************************************/
    (defun getClosestEdge (xy bBox)
      (let (edgeData distances)
	(setq edgeData
	      (list
		(list (xCoord (lowerLeft bBox)) (xCoord xy) 'left)
		(list (yCoord (lowerLeft bBox)) (yCoord xy) 'bottom)
		(list (xCoord (upperRight bBox)) (xCoord xy) 'right)
		(list (yCoord (upperRight bBox)) (yCoord xy) 'top)
		))
	(setq distances 
	      (foreach mapcar edge edgeData
		       (list (abs (difference (car edge) (cadr edge)))
			     (caddr edge))))
	(cadar (sortcar distances 'lessp))
	)
      )

    Regards,

    Andrew.

     

  • vijay_arm
    Please note there is a typo in the above script, which can result in false returns.

    (list (yCoord (upperRight bBox)) (yCoord xy) 'top)

    thanks
    Vijay
  • Andrew Beckett

    Thanks Vijay - it was a deliberate mistake to see if anyone was paying attention! Seriously - thanks for finding it (I fixed it in the post above for convenience too). I guess it didn't show up as a problem in my test data!

    Andrew

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