vxlInstSpacingRule Property

vxlInstSpacingRule float f_value

Description

Defines a spacing offset when pins are on a different net.

Symbol master Add Property form
Name	`vxlInstSpacingRule`
Type	float
Value	f_value

Add CDF Parameter form
Add After Parameter	As First Parameter
paramType	float
name	`vxlInstSpacingRule`
defValue	f_value

A user-defined function, called abutFunction, can be used to define a spacing offset when pins are on a different net. When you set the vxlInstSpacingRule to float, two pins of the same abutment class and different nets are pushed apart a distance equal to the maximum values of the two vxlInstSpacingRule pins. To control the abutment spacing set the vxlInstSpacingRule to abutFunction.

abutFunction is not the name of your custom abutment function, but is the property that is set to the name of your abutment function.

dbReplaceProp(sObj~>dbId "abutFunction" "string" "myCustomAbutmentFunction")

dbReplaceProp(sObj~>dbId "vxlInstSpacingRule" "string" "abutFunction")

You can write your own spacing function for the two instances involved. For example, myCustomSpacingFunc ( )is to be called in the body of the user defined abutment function (abutFunction). The myCustomSpacingFunc ( ) must return a float value to be effective.

There are two numbers passed to the abutment function, the connection condition (1, 2, or 3)and the abutment event (1, 2, 3, or 4). The connection condition (3) is for different nets. The sequence for nonabuttable pins should be the same as for abuttable. The calling of the abutment function for adjusting the Pcells (Event 2) and then one to calculate the spacing of the resultant reference edges (Event 4). This allows you to adjust the well or isolation on the Pcell and then space the devices based on the reference edges.

To get the spacing offset when pins are on different nets add the following case in your custom abutment function.

(4
   if(instA~>w > 3.0 && instB~>w > 3.0
   then
      result = 3
   else
      result = 1
   )
);; end of case 4

You can use the layout editor user interface to enter properties on the pins in the same way that you enter the permuteRule properties.

If you need to add a variable spacing rule to the pin, set the vxlInstSpacingRule to abutFunction as shown below:

dbReplaceProp(sObj~>dbId "vxlInstSpacingRule" "string" "abutFunction")

The properties to set automatic spacing are listed below.

Virtuoso Layout Suite XL: Connectivity Driven Editing User Guide
Product Version IC23.1, November 2023