File Organisation

Overview

Primary and secondary design units can be split into several files
Advantages of
- Several Packages
  - Modularisation and reuse aspects (IEEE, corporate, project packages)
  - Separation of synthesizable from simulation only VHDL
- Package / Package body Separation
  - No recompilation of the design hierarchy  if body (implementation) changed
- Entity / Architecture Separation
  - System design (top level, structural) independent from implementation
  - Several modelling alternatives (e.g. behavioral, RTL) possible
- Several top level configurations
  - Adjust design to goal of simulation
  - Comparison of alternative architectures

Notes

VHDL offers several possibilities of implementing hierarchy.

The language introduces the main hierarchy into the design with the philosophy of entity/architecture pairs and their instantiation as components. This leads to a strict separation of interface and implementation.

With the help of packages, libraries and concise naming conventions it is possible to manage huge designs with a plenty of files. Switching between the different implementations during simulation is done with the configuration mechanism.