| FreePCB User Guide | Version 1.2

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5. PCB Layout (continued)

5.12 Mounting Holes

Mounting holes are used to attach a PCB to an external structure such as a bracket or enclosure. In FreePCB, a mounting hole is a part which consists of a single through-hole pin. The padstack for the pin may include pads which can be used to connect the mounting hole to a net, just like any other pin. The actual hole in the padstack will be shown in the color for the drilled-hole layer. If the mounting hole has pads, they will be shown in the color for their copper layer.

Since the mounting hole is a part, it can be added to the partlist like any other part. It can be included in the netlist file, or it can be added using the A dd > Pa rt or Project > Parts... menu selections. Some mounting holes of different sizes are included in the library file th_mounting_hole.fpl.

Examples of mounting holes are shown below. H5 has no pad, H6 has a round pad and H7 has a square pad.

When using the mouse to select a mounting hole, you can select either the part or the pin. You would select the part if you wanted to move it, for example, while you would select the pin to add a connection to a net. The selection rectangles for the part and the pin are almost exactly the same size. Since the pad has priority, you will select the pad first when you click on it. You must click again to select the part. You can tell whether you have selected the pad or the part by looking at the selection rectangle or by checking the status bar.

In the examples below, the left image shows the pad for H6 selected. The right image shows the part for H6 selected, after clicking again.

Pad selected |  | Part selected

Selecting the reference designator for a mounting hole may be difficult if it overlaps the pad, since clicking on it with the mouse will select either the part or the pin. To get around this, you can use the selection mask to disable selection of parts and/or pins. Since the reference designator of a mounting hole is not very useful, you may want to make it invisible by selecting and it and using F1 ("Set Size") to make its character height zero. You can also set the character height by selecting the part and using Set Ref. Text Size from the right-click menu, which is how you would make the reference designator visible again if you wanted to.

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