docs/wiki/geda-gschem_ug-pins_nets_buses.html

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  12 <a href=.>start</a>&nbsp;=>&nbsp;<a href=geda-gschem_ug.html>gschem_ug</a></br>
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  18 <!-- EDIT1 TABLE [1-92] -->
  19 <h2 id="pinsnetsandbuses">Pins, nets and buses</h2>
  20 <div class="level2">
  21
  22 <p>
  23 Connectivity in gEDA schematics and symbols is shown using pins, nets and buses.
  24 </p>
  25 <ul>
  26 <li class="level1"><div class="li"> Pins are used in symbols, and represent either a physical pin on an electronic component, or a logical connection to a subcircuit schematic.</div>
  27 </li>
  28 <li class="level1"><div class="li"> Nets are used in schematics.  They represent individual wires, and are used to connect together the pins of <a href="geda-gschem_ug-components.html" class="wikilink1" title="geda-gschem_ug-components.html">components</a>.</div>
  29 </li>
  30 <li class="level1"><div class="li"> Buses are also used in schematics, and represent &quot;bundles&quot; of multiple nets.</div>
  31 </li>
  32 </ul>
  33
  34 <p>
  35 Nets, pins and buses can have <a href="geda-gschem_ug-attributes.html" class="wikilink1" title="geda-gschem_ug-attributes.html">attributes</a> attached to them to control how they are interpreted by <a href="geda-gnetlist_ug.html" class="wikilink1" title="geda-gnetlist_ug.html">gnetlist</a>.
  36 </p>
  37
  38 </div>
  39
  40 <h3 id="addingandeditingpins">Adding and editing pins</h3>
  41 <div class="level3">
  42
  43 <p>
  44 Pins have a <em>connectible end</em>, which is highlighted with a colored swatch, and a static end.  Nets can only be connected at the highlighted end.
  45 </p>
  46 <div class="notetip">If you are designing a symbol, see also the <a href="geda-gschem_symbol_creation.html" class="wikilink1" title="geda-gschem_symbol_creation.html">Symbol Creation Guide</a>.
  47 </div>
  48 <p>
  49 To begin adding pins, use <strong>Add→Pin</strong>.  Left-click once to position the connectible end of the new pin, and left-click again for the other end.  To finish placing pins, right-click.
  50 </p>
  51
  52 <p>
  53 If you <a href="geda-gschem_ug-selecting.html" class="wikilink1" title="geda-gschem_ug-selecting.html">select</a> a pin, handles will appear for each of its endpoints.  You can left-click and drag these with the mouse to change the position of the pin&#039;s endpoints.
  54 </p>
  55
  56 </div>
  57
  58 <h3 id="addingandeditingnets">Adding and editing nets</h3>
  59 <div class="level3">
  60
  61 <p>
  62 Nets are made up of straight <em>net segments</em>, and net connections are formed either where two net segment ends meet, or where a net segment end meets a net segment midpoint.  If two net segments cross, they do not form a connection.  A net connection is marked by a circular cue, and a disconnected (or &quot;floating&quot;) net end with a square cue.
  63 </p>
  64
  65 <p>
  66 To add a net segment, use <strong>Add→Net</strong>.  There are two modes for adding nets: normal mode, and magnetic mode (the default).  To switch between them, use <strong>Options→Toggle Magnetic Net</strong>.
  67 </p>
  68 <ul>
  69 <li class="level1"><div class="li"> In <em>magnetic mode</em>, new nets snap onto nearby connectible points on pins and nets.  The target location that the next net point will snap to is highlighted with a circle.</div>
  70 </li>
  71 <li class="level1"><div class="li"> In <em>normal mode</em>, new nets snap to the grid like other newly-created objects.</div>
  72 </li>
  73 </ul>
  74
  75 <p>
  76 Nets will be added using only combinations of horizontal and vertical segments, unless you hold down the <kbd>Ctrl</kbd> key, in which case segments at any angle will be used.
  77 </p>
  78
  79 <p>
  80 Selected nets can be modified by dragging the handles on their endpoints in the same way as pins.
  81 </p>
  82
  83 </div>
  84
  85 <h3 id="addingandeditingbuses">Adding and editing buses</h3>
  86 <div class="level3">
  87 <div class="noteimportant">Since buses are not currently fully supported by <a href="geda-gnetlist_ug.html" class="wikilink1" title="geda-gnetlist_ug.html">gnetlist</a>, buses are commonly used only for documentation purposes.
  88 </div>
  89 <p>
  90 Like nets, buses are made up of <em>bus segments</em>, follow similar connectivity rules, and can be edited in the same way.
  91 </p>
  92
  93 <p>
  94 To add buses, use <strong>Add→Bus</strong>.  When adding buses, each new bus segment is constrained to be either horizontal or vertical, unless you hold down the <kbd>Ctrl</kbd> key.  Buses do not support magnetic mode.
  95 </p>
  96
  97 <p>
  98 When you connect a net to a bus, a &quot;bus ripper&quot; symbol is automatically inserted. This allows two nets to be attached to the same point on a bus from opposite sides without shorting together.
  99 </p>
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