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geda:gnetlist_ug:slotting [2012/11/17 09:46]
geda:gnetlist_ug:slotting [2012/11/17 10:25] (current)
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 ===== Slots and slotting ===== ===== Slots and slotting =====
 +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. ​ [[geda:​gschem_ug|gschem]] and gnetlist provide support for working with these by using //slots//.
 +<note tip>​Check the "​4001-1.sym"​ symbol in the "​4000-series logic" symbol library for an example of how to use slotting and [[implicit pins]].
 +Detailed information on slotting attributes can be found in the [[geda:​master_attributes_list|Master Attributes List]].</​note>​
 +gnetlist uses several symbol attributes to enable slotting. ​ All must be present for gnetlist to process a slotted component correctly.
 +  - Every pin must have a "''​pinseq=''"​ attribute and a "''​pinnumber=''"​ attribute.
 +  - The "''​numslots=''"​ attribute indicates how many slots a component has.
 +  - There must be one "''​slotdef=''"​ attribute for each slot.  This contains information about the pin numbers of the pins associated with each slot.
 +  - A "''​slot=''"​ attribute attached to each component in the schematic indicates which particular slot to use.
 +When processing a slotted component, gnetlist first looks for a "''​slotdef=''"​ attribute matching the value of the "''​slot=''"​ attribute. ​ It uses the value of the "''​slotdef=''"​ attribute to renumber the pins for the correct slot.  It then merges the component with other components with the same "​refdes"​.
 +<note important>​gnetlist does not currently support slotting across hierarchy. ​ The slots in a package cannot be split between different subcircuits.</​note>​
geda/gnetlist_ug/slotting.1353163605.txt.gz ยท Last modified: 2012/11/17 09:46 by peter-b