Impact of Hardware/Software Partitioning and MicroBlaze FPGA Configurations on the Embedded Systems Performances - Complex System Modelling and Control Through Intelligent Soft Computations - page 699

2.1 Design Methodologies, Challenges

Embedded applications require increasingly sophisticated functionalities and severe
constraints. They incorporate many application areas such as telecommunication,
avionics, automotive, medical implants, domestic appliances, etc. These increasing
complexities require functional constraints (computation capacities, reduced power
consumption, miniaturization of the implementation area, etc.) and non-functional
constraints (minimum time-to-market, reduced cost, maximum life, growth in the
amount of productions, etc.). To increase the embedded systems performances,
researchers and industry have focused on two areas of research. First, technological
area that is based on the evolution of the integration level of integrated circuits.
Second, methodological area, which is based on re nement of design methodolo-

gies. Faced with the physical limits of technical evolution, manufacturers of
embedded systems had to demonstrate a different reactivity. They had to continu-
ously improve their techniques and design approaches to increase the embedded
systems performances.
In our study, we examine different design architectures of complex embedded
systems. Our contribution lies in the hardware/software partitioning step starting
from high level speci

cation. Also, a new step has been added to the hardware/
software partitioning which is the selection of the best con guration of the used

soft-core processor.

2.1.1 Design Implementation Architectures

Traditional hardware FPGA design approaches are complex. This reduces FPGA
productivity. Hardware implementation uses a low-level speci cation, VHDL or

Verilog languages or combination of both, to implement embedded applications.
Their implementation process consists of the (a) de

nition of application at a low-
level specification (b) synthesis, (c) implementation, (d) simulation and (e) tests and
veri

cation steps. With the integration of soft-cores processors into FPGA,
designers become able to implement complex systems on software architecture. As
input, they employ a high-level speci cation, compile it and implement it into soft-

cores processors.
Several researches demonstrate that software implementation of embedded
systems allows

cations), ease of integration,
reduction of design time and bad performances. However, hardware implementa-
tion of the same application greatly achieves high performance constraints in a long
design time.
Now, FPGA offers many advantages. It can be used in all embedded systems

fl flexibility (ability to modify speci

fields (image processing, aerospace systems, security and industrial applications,
etc.). It can be implemented on different architectures (hardware, software or both
hardware/software) using different design methodologies (Joven et al. 2011 )as
illustrated on Fig. 1 .