next up previous contents index
Next: MinSpaceTo Rule Up: Edge Rules Previous: MinWidth Rule   Contents   Index


MinSpace Rule

Syntax: MinSpace [EdgeArgs] space_in_microns | SpacingTable table definition [Diagonal diag_space] [SameNet snet_space] [string]

For the parts of each edge of the source that are not coincident or overlapping with source-compatible figures, a rectangle extending normally from the edge out of the source figure by the given dimension is constructed. The test fails if the constructed rectangle has nonzero intersection area with source-compatible figures. Note that the angle formed by two adjacent edges of a figure measured outside the figure must be 90 degrees or greater, i.e., this rule prevents acute notches in polygons, and acute bends in wires. Figure 15.9 illustrates the test performed under this keyword, for no Region.

If a spacing table (see 15.4) is specified and active, the dimension used is computed from the spacing table, for Manhattan edges. An inactive table will still supply the default spacing, which is taken as the space_in_microns.

If the Diagonal clause is given with positive diag_space, then the diag_space value will be used when the edge being tested is nonorthogonal.

The SameNet clause is currently not implemented, and its presence has no effect.

The MinSpace test also fails if the space from a corner of a source figure to another non-touching compatible figure is less than the dimension.

When importing Virtuoso technology data, the minSpacing single-layer constraint maps directly to this rule.

The Diagonal and SameNet clauses are set by minDiagonalSpacing and minSameNetSpacing single-layer constraints when importing virtuoso technology data. These may have their own reference strings. To keep these distinguishable, the string can actually be three double-quoted strings, e.g., the form is

"# rule description" "minDiagonalSpacing string" "minSameNetSpacing string"

This guarantees that the original reference strings are regenerated when the !dumpcds command is used to generate a Virtuoso technology file. If a component string doesn't exist, one can use "" (two double-quote marks) as a placeholder. Strings to the right that don't exist can be skipped entirely.

Figure 15.9: The MinSpace test. The edge-to-edge spacing between regions on the present layer must not be less than the given dimension.
\begin{figure}
\vspace{1.5ex}
\begin{center}
\epsfbox{images/minspace.eps}
\end{center}\end{figure}


next up previous contents index
Next: MinSpaceTo Rule Up: Edge Rules Previous: MinWidth Rule   Contents   Index
Stephen R. Whiteley 2019-11-22