docs/wiki/geda-gnetlist_ug-slotting.html

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  14 <div class="table sectionedit2165"><table class="inline">
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  16                 <td class="col0 leftalign"> « <a href="geda-gnetlist_ug-hierarchy.html" class="wikilink1" title="geda-gnetlist_ug-hierarchy.html">Hierarchy</a>  </td><td class="col1 centeralign">  <strong><a href="geda-gnetlist_ug.html" class="wikilink1" title="geda-gnetlist_ug.html">gEDA gnetlist User Guide</a></strong>     </td><td class="col2 rightalign">  <a href="geda-gnetlist_ug-implicit_pins.html" class="wikilink1" title="geda-gnetlist_ug-implicit_pins.html">Implicit pins</a> » </td>
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  19 <!-- EDIT2165 TABLE [1-103] -->
  20 <h2 class="sectionedit2166"><a name="slots_and_slotting" id="slots_and_slotting">Slots and slotting</a></h2>
  21 <div class="level2">
  22
  23 <p>
  24 Some integrated circuits provide several identical and interchangeable devices in a single package.  The classic “4000” series of logic devices is a good example of this; for example, each 4001 package contains four 2-input NOR gates.  <a href="geda-gschem_ug.html" class="wikilink1" title="geda-gschem_ug.html">gschem</a> and gnetlist provide support for working with these by using <em>slots</em>.
  25 </p>
  26
  27 <p>
  28 <p><div class="notetip">Check the “4001-1.sym” symbol in the “4000-series logic” symbol library for an example of how to use slotting and <a href="geda-gnetlist_ug-implicit_pins.html" class="wikilink1" title="geda-gnetlist_ug-implicit_pins.html">implicit pins</a>.
  29 </p>
  30
  31 <p>
  32 Detailed information on slotting attributes can be found in the <a href="geda-master_attributes_list.html" class="wikilink1" title="geda-master_attributes_list.html">Master Attributes List</a>.
  33 </div></p>
  34 </p>
  35
  36 <p>
  37 gnetlist uses several symbol attributes to enable slotting.  All must be present for gnetlist to process a slotted component correctly.
  38 </p>
  39 <ol>
  40 <li class="level1"><div class="li"> Every pin must have a ”<code>pinseq=</code>” attribute and a ”<code>pinnumber=</code>” attribute.</div>
  41 </li>
  42 <li class="level1"><div class="li"> The ”<code>numslots=</code>” attribute indicates how many slots a component has.</div>
  43 </li>
  44 <li class="level1"><div class="li"> There must be one ”<code>slotdef=</code>” attribute for each slot.  This contains information about the pin numbers of the pins associated with each slot.</div>
  45 </li>
  46 <li class="level1"><div class="li"> A ”<code>slot=</code>” attribute attached to each component in the schematic indicates which particular slot to use.</div>
  47 </li>
  48 </ol>
  49
  50 <p>
  51 When processing a slotted component, gnetlist first looks for a ”<code>slotdef=</code>” attribute matching the value of the ”<code>slot=</code>” attribute.  It uses the value of the ”<code>slotdef=</code>” attribute to renumber the pins for the correct slot.  It then merges the component with other components with the same “refdes”.
  52 </p>
  53
  54 <p>
  55 <p><div class="noteimportant">gnetlist does not currently support slotting across hierarchy.  The slots in a package cannot be split between different subcircuits.
  56 </div></p>
  57 </p>
  58
  59 </div>
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