VHDL component placement In VHDL, in which declaration region is a COMPONENT typically declared before it is instantiated and port-mapped?

Introduction / Context:
Structural VHDL allows designers to build larger systems by wiring together component instances. A component declaration introduces the interface of a reusable block so that it can be instantiated and connected within an architecture. Knowing where to place this declaration is critical for correct coding style and tool compatibility.

Given Data / Assumptions:

• We are using component instantiation (as opposed to direct entity instantiation).
• The design unit includes an entity and an architecture.
• Libraries and packages are already made visible via library/use clauses.

Concept / Approach:
A COMPONENT is declared in the declarative region of an architecture (or in a package for broader reuse). The declaration specifies the component's generics and ports so that later, within the same architecture, you can create labeled instances with port map associations. The LIBRARY clause merely makes libraries visible; it does not host component declarations. The ENTITY describes the external interface of the current design unit, not third-party component declarations. A port map is part of an instantiation statement, not a declaration region.

Step-by-Step Solution:

Verification / Alternative check:
Tool templates and vendor examples show component declarations inside architectures or packages, followed by instantiations referencing those declarations.

Why Other Options Are Wrong:

• Library: Used for visibility and referencing, not for component declarations.
• Entity: Declares the interface of the current module, not external components for instantiation.
• Port map: Part of the instantiation statement, not a declaration section.

Common Pitfalls:
Confusing component instantiation with direct entity instantiation; placing the declaration after use; or omitting needed packages that define subtypes used in the component ports.

Final Answer:
Architecture