Grid and Edge Snapping

These keywords define the grid and edge snapping parameters. These can be reset from within Xic from the Snapping page of the Grid Setup panels associated with the drawing windows. The parameters given in the technology file apply to the main window, which are inherited by sub-windows when created. The parameters can subsequently be changed with the panel on a per-window basis.

For the main drawing window, the Main Window sub-menu of the Attributes Menu provides the Set Grid button, which brings up the Grid Setup panel. Sub-windows have the Grid Setup panel available from the Attributes menu in the sub-window. Pressing Ctrl-g while a drawing window has focus will also bring up the panel.

MfgGrid delta
If set nonzero, the actual SnapGridSpacing used will be constrained to be a multiple of this value. This applies in physical mode only.

This can be considered to be the ``pixel'' size of the mask. The SpotSize variable is related, see this topic in E.11 for more information.

SnapGridSpacing spacing
The spacing is a floating point number which represents the spacing, in microns, between snap points. This applies to physical mode only.
Default: 1.0 microns

The electrical grid is set to spacing value 1.0 with unit snap per grid on program startup, which can't be changed from the technology file. The electrical grid can be changed within Xic from the Grid Parameters pop-up, in the unusual circumstance that non-default values are needed.

$\parbox{4in}{{\tt SnapPerGrid} {\it num}\\ {\tt GridPerSnap} {\it num}}$
At most one of these keywords should be given. The num is an integer 1-10. These apply to physical mode only.

If SnapPerGrid is given, then the fine grid lines will be spaced num*SnapGridSpacing apart. If GridPerSnap is given, fine grid lines will appear at SnapGridSpacing/num intervals.
Default: 1

$\parbox{6in}{{\tt EdgeSnapping} [{\tt none}$\vert${\tt some}$\vert${... ...] [{\tt +}$\vert${\tt -edge\_of\_wire}] [{\tt +}$\vert${\tt -path\_of\_wire}]}$
This keyword sets the initial state of the controls of the Edge Snapping group in the Snapping page of the main window Grid Setup panel. All fields are optional, with the effective default being

EdgeSnapping some -off_grid -non_manh +edge_of_wires -path_of_wires

Only the first letter of the keywords is needed, and recognition is case-insensitive.

The first word specifies when edge snapping is enabled:

none	not enabled
some	enabled in some commands (the default)
all	always enabled

The remaining items are flags that must start with a + or - character. The + turns the option on, the - turns the option off. These have obvious correspondence to the check boxes in the Edge Snapping control group in the Grid Setup panel, and set the initial state of the check boxes for the main window.

$\parbox{6.5in}{{\tt RulerEdgeSnapping} [{\tt none}$\vert${\tt some}... ...] [{\tt +}$\vert${\tt -edge\_of\_wire}] [{\tt +}$\vert${\tt -path\_of\_wire}]}$
This keyword uses the same syntax as the EdgeSnapping keyword, and species the initial edge snapping mode when the Rulers command in the View Menu is in effect. This command has its own settings, with the default being that all flags are enabled.

RulerSnapToGrid [y| n]
This boolean keyword specifies the initial state of grid snapping in the Rulers command in the View Menu In the command, the mode can be toggled by presing the period (`.') key. By default, grid snapping is asserted.