User Guide

Whenasymbolisdefined,apinisplacedatacertainposition.
PIN'GND'PWRNONESHORTR180(0.20.4);
Youdrawarectangularforbiddenareainlayer41 tRestrict:
LAYERTRESTRICT;
RECT(0.50.5)(2.54);
5.3 Gridsandthe CurrentUnit
EAGLEperformsitsinternalcalculationsusingabasicgridsizeof
1/10 000 mm (0.1 micron). Any multiple of that can be set as the work
-
inggrid.
Microns, mils, inches and mm can be used for the unit. The current unit
assetwiththeGRIDcommandappliestoallvalues.
You should always use the pre-set 0.1 inch grid for schematic diagrams.
This grid should also be used when defining schematic diagram symbols
intheLibraryEditor.
When starting the design of circuit boards or libraries it pays to give
prior thought to the question of which grid size (or sizes) will be used
as a basis. For example, it is only the origin of a package that will be
pulled onto the board’s placement grid. All other objects constituting
the package (such as pads) are placed relative to that point on the board,
justasitwasdefinedinthelibrary.
The basic rule for boards is: always make the grid as big as possible and
assmallasnecessary.
Various grid sizes can be preset in the eagle.scr file for different types of
editorwindows(seepage 79).
TheGridMenu
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PrinciplesforWorkingwithEAGLE