Now all submodules must be merged into one design, the complete camera controller. So all modules have to be connected on a new level of hierarchy. This is called structural modelling.
Structural modelling means the use (instantiation) and wiring of components resulting in a net list. VHDL provides the following means for structural modelling:
Before you can use an object in VHDL you have to declare it. As in VHDL'87 only components can be instantiated these have to be declared first. This is done in the declarative part of an architecture or within a package which then has to be referenced.
The actual instantiation is the integration and wiring of the component. The component configuration determines which entity has to be used for a specific component instantiation. If the name of the component instantiated and the name of the entity to be used are identical (mandatory for synthesis!) then no specific component configuration has to be given.
The interface of the top module is shown in the following picture:
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