VIA

Function

Adds vias to a board.

Syntax

VIA ['signal_name'] [diameter] [shape] [layers] [flags] *..

When the VIA command is active, a via symbol is attached to the cursor. Pressing the left mouse button places a via at the current position. When vias are added to a signal, a short circuit test is performed. If you try to connect different signals, EAGLE will ask you if you really want to connect them.

Signal name

The signal_name parameter is intended mainly to be used in script files that read in generated data. If a signal_name is given, all subsequent vias will be added to that signal, and no automatic checks will be performed.
This feature should be used with great care because it could result in short circuits, if a via is placed in a way that it would connect wires belonging to different signals. Please run a Design Rule Check after using the VIA command with the signal_name parameter!

Via diameter

Entering a number changes the diameter of the via (in the actual unit) and the value remains in use for further vias. Via diameters can be up to 0.51602 inch (13.1 mm).

The drill diameter of the via is the same as the diameter set for pads. It can be changed with

CHANGE DRILL diameter *

Shape

A via can have one of the following shapes:

Square
Round
Octagon

Vias generate drill symbols in the Drills layer and the solder stop mask in the tStop/bStop layers.

Like the diameter, the via shape can be entered while the VIA command is active, or it can be changed with the CHANGE command. The shape then remains valid for the next vias and pads.

Note that the actual shape and diameter of a via will be determined by the Design Rules of the board the via is used in.

Layers

The layers parameter defines the layers this via shall cover. The syntax is from-to, where 'from' and 'to' are the layer numbers that shall be covered. For instance 2-7 would create a via that goes from layer 2 to layer 7 (7-2 would have the same meaning). If that exact via is not available in the layer setup of the Design Rules, the next longer via will be used (or an error message will be issued in case no such via can be set).

Flags

The following flags can be used to control the appearance of a via:

STOP	always generate solder stop mask

By default a via with a drill diameter that is less than or equal to the value of the Design Rules parameter "Masks/Limit" will not have a solder stop mask. The above STOP flag can be used to force a solder stop mask for a via.