You do not have to declare all output pins as ports.Any undeclared outputs become no-connects or redundant nodes.
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The Board of Directors are the representatives of the Shareholders, i.e.
they are selected by the Shareholders of the company.
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To identify I/O ports in the lower-level source: You identify an ABEL-HDL source's input and output ports with an Interface declaration directly following the Module statement.
The Interface statement defines the ports in the lower-level source that are used by the top-level source.The referencing of a logic description is called "instantiation." In a hierarchical design, you can't instantiate a top-level source from a source instantiated below that source.You use hierarchy declarations in an upper-level ABEL-HDL source to refer to (instantiate) another ABEL-HDL source.Buried nodes in lower-level sources are handled as follows: Lower-level nodes that do not fanout are propagated to the higher-level source and become dangling nodes.Optimization may remove dangling nodes from the lower-level source.Redundant nodes can later be removed from the designs during post-link optimization.