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Pattern Rules

Ane of Eagle'due south more of import but less flashy features is its back up for blueprint rule sets. These are sets of rules for things like spacing between board features and minimum sizes that all correspond to the tolerances and capabilities of a board manufacturer. Setting these pattern rules will help you lot design your board in a way that volition fit the requirements and capabilities of your lath manufacturer.

The lath house volition specify these tolerances similar on this page for OSH Park and you lot can manually create your own design dominion sets based on these requirements, even so in our instance we're going to download and use the design rule files that OSH Park provides.

Go on in mind that these design rules are for theminimum size that a manufacturer volition produce, not the only size! In nigh cases, it is wise to apply larger sizes than the minimum every bit the closer, smaller and tighter your design, the more than "fragile" your design will exist, meaning it will be susceptible to issues occurring from the normal and expected variances that occur during manufacturing.

Using Design Dominion Files

Go to the OSH Park Eagle blueprint rule page and download the "oshpark-2layer.dru" design rule file. One time downloaded, while in the board window, open theEdit carte du jour  and selectBlueprint rules...
In the window that opens, click Load, select the OSH Park design rule file you just downloaded, and clickOK.

Once you have loaded the new blueprint dominion file, let's run a blueprint rule cheque to meet if the lath as information technology is now has any design rule errors.

By default Eagle will continuously bank check for Design Dominion errors. You can plow this behavior on or off using the "Live DRC" checkbox under Options>Prepare..>DRC tab

Click theDRC button to open the DRC window, and clickCheck

This will pop up a dialog that will list any current board characteristic that violates the blueprint rules.

When yous run the design dominion check, it volition highlight several errors; the starting time isAirwires which are connections from nets that accept non been completed using traces. This is to exist expected because we have not created any traces however.

The second course that might announced aredimension errors that come from the pads for the headers beingness too close to the outline of the lath. One of the design rules that OSH Park and other board houses specify is how much clearance there must be between the board outline and anything on the copper layers.

We can use themovement tool to adjust the position of the board outline and headers to provide an appropriate amount of clearance.

Make sure Not to move the individual Trinket headers by themselves! Use the group>move command to preserve their spacing

You will likely notice however that you can only brand relatively coarse movements

The movement flexibility, in steps, is due to the default size of thegrid.

Grid

Eagle allows you to specify a filigree that board features volition snap to when beingness moved or created. The units you specify volition also determine the units used for measurements throughout Eagle. When routing a board I prefer to prepare the filigree size somewhere betwixt ii.5 to 10 mils. This allows for a fair corporeality of flexibility and, since design rules are often in mils, using mils for the units helps me make sure I'm keeping the design rules in mind while working on the board.

Open it by clicking the Grid icon. It will ask y'all to specify the filigree size value and units like millimeters or mils (1/1000th of an inch). Set up the size to 10 and the units tomils and theAlt totwo.5.

Now that you take adjusted the size of the filigree, select theMotility tool once more and movement the position of the board outline to remove the dimension errors. If y'all holdAlt (Option on a mac) while moving something, you will temporarily change to the alternate filigree that y'all've set to a finer pitch, assuasive you to make even effectively adjustments. After working working in Eagle for a bit y'all'll likely develop your own preferences and tin can set the grid accordingly.

This guide was commencement published on Feb 05, 2019. It was last updated on Feb 05, 2019.

This folio (Working with Design Rules) was last updated on Apr 14, 2022.

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