What is instantiation in vhdl

This ability was intended to be used to map primitives from different vendor libraries to a standard component declaration. The perceived complexity involved in configuration was countered with portability libraries such as LPM Library of Parameterized Modules which add a different axis of complexity via he use of attributes and generics while standardizing interface names and reducing the number of library primitives.

Behavioral synthesis has advance to the point both methods of structural design specification have fallen the way side. FPGA vendor support for explicit configuration declarations has also historically lagged. I agree that component instantiation is painfully verbose, but it's more readable in case the entity is not declared on the same source file.

Also, on really big projects. It allows to separate the compilation of each entity. So changing one entity doesn't mean recompiling the whole project. And allows to easily swap with behavioral archs for simulation. Ie: a DRAM will just be a bunch of ports of your fpga. Or you may download a dram model and verify that your code is working as expected. You don't need to go back and change the instantiation each time you simulate something.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Asked 5 years, 7 months ago. Active 4 years, 7 months ago. Viewed 12k times. Related Article It seems to me that Entity Instantiation is always preferable unless you don't have an architecture implemented yet and you just want to define a black box.

Since it is possible to define both the generic map and the architecture for any entity: entity work. Improve this question. Community Bot 1 1 1 silver badge. With entity instantiation, you have to write the entity before you can compile this file With a component, you can defer that step until you link elaborate the design. Right, that's what I meant with "It seems to me that Entity Instantiation is always preferable unless you don't have an architecture implemented yet and you just want to define a black box".

I realize now that sentence wasn't very clear. What are other benefits though? The articles I listed claim that the component instantiation approach is more flexible and I can't see why.

IEEE Std 6. In such a direct instantiation, the component instantiation statement contains the design entity name and optionally the name of the architecture to be used for this design entity. The reserved word entity follows the declaration of this type of the component instantiation statement Example 3.

If architecture name is not specified in an instantiation of a design entity, the last compiled architecture associated with the entity will be taken. The structural specification of an arithmetic-logic unit ALU uses an instantiation of a HalfAdder component.

Note that the component is instantiated with signals of the ALU system. The signals are associated positionally. This structural architecture performs the same function as in the Example 1. The only difference lies in the way the association list is specified for the component ports - the signals are associated with named association. Show diagram after run.

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