Massimo Talia is an electronic engineer whose website is http://www.taliawebs.com. The document discusses different layers of embedded system design including application, middleware, operating system, firmware, system design, logic design, and PCB design layers. It also discusses embedded software design, firmware based design, system based design, logic based design, PCB based design, and verification and validation processes.

1. Massimo Talia
Electronic Engineer
Web address: http://www.taliawebs.com

2. Summary
The Embedded Systems
Layer based Embedded Design
Embedded Software design
Firmware based design
System based design
Logic based design
PCB based design
Verification and Validation

3. The embedded systems
“Embedded system” is a generic
term for a broad range of systems
which are based on electronic
microprocessors. Nevertheless, all
embedded systems have a
common feature in that they
interact with the real physical
world, controlling some specific
hardware or plants.

4. Layer based Embedded Design
The design of an «embedded system » can be divided in
different layers or grained levels, so that it’s easier the
design flow and the work-group management .
Layer based design
(TOP-DOWN)
Application
Middleware SDK
RTOS (OS )
Firmware
System Design
Embedded
Software
Logic Design
PCB Design
Embedded
Hardware

5. Embedded software design
The embedded software design begin from the high level
software requirements in compliance with the industrial
standards and it ends with the verification and validation.
Every design layer is connected each other from one or
more requirements by the tracebility matrices. Every
requirement describes one or more functionalities, which
must be implemented in software or it can be a not
functional requirement. In the Safety critical software you
need respect the «SIL» (software integrity level),
guarantee high reliability, availability, mantainability and
safety. The embedded software code is developed for a real
time operating system (RTOS) which is inside the target
(Hardware equipment).

6. Firmware based design
The firmware design is the last layer before the System
design and identification. The firmware contains the
main functionalities for accessing to the hardware
board. An example is the MAC level access algorithm
(medium access control). The firmware can be
implemented by an high level programming language
or low level language as assembly . It’s most common
use implementing the firmware under the operating
system layer.

7. System based design
The system based design is the high level hardware design
process, which identifies a part or the whole hardware. It’s
part of the hardware prototyping , requirements and HDL
generation. Every hardware system communicates with one
or more external sources or a plant. The design process is
similar to the embedded software design, but with different
standards and tools.

8. Logic based design
This hardware design process provides for the use of
FPGA simulators in order to implement in RTL and
VHDL or Verilog the logical circuits, optimize the
clock time constraints, the power consumption and
dowload the bytecode on the prototyping board. The
typical process flow depends on the industrial
standards or FPGA vendor process flow. In the
Aerospace industry for example, there is the «V» flow
in compliance with military standards.

9. PCB based design
In this case the design process flow concerns the
hardware layout and schematic design. It’s the lowest
level possible in the hardware design, because you
print on the fiber glass board the electronic layout
tracks and the position of the electronic parts.

10. Verification and Validation
For every design flow there is always one o more
phases of verification and validation as it’s possible to
read below.