Starting from the HiLeS formalism elements, one can use HiLeS to make a high level description of a system. The structures specifications permit to detail the system mechanism (Figure 1a). The Control Net – Blocks interaction describes the behavior of the system, the control instruction execution and the activities scaling on a hierarchic structure. Multiple hierarchical levels (Figure 1 b) allow to represent the system at different levels of detail.

Figure 1. HiLes hierarchies.

Multiple Architecture Principle

This principle defines the structural construction of blocks by the  way of using one or multiple architectures. The principle allows the  designer to define different solutions for a given functionality without changing the interface. This principle is inherent to the classic
VHDL entity-architecture construction and it has been already suggested by the “paradigm of reconfigurable models” [Her02] for the systems conception.  To better show the principle, the block Structural_1 (Figure 2 a) has 4 inputs (In_01, In_02, In_03, In_04) and an output (Out_01). The icon at the top-right corner of the block indicates the presence of at least one architecture. The block’s Inputs/Outputs are kept, and we propose two possible solutions at Figure 2 b and c.

Figure 2. Different architectures for the same Structural Block