Assurance Process for Complex Electronics
Purpose of this site
This web
site provides details on an assurance process
for complex electronics. This process is part of a research project
that will help determine what assurance activities NASA organizations
may be required to perform for complex electronics.
This web
site also functions as an education tool for managers, systems
engineers, and assurance engineers who are looking to learn more about
complex electronics. The Getting
Started link on the left will take you to a page that suggests what
parts of the web site to look at, depending on your interest and
experience.
What are complex electronics?
Complex
electronics are Programmable Logic Devices (PLD) that can be used to implement
specific hardware circuits. The devices that are included under the
label of complex electronics are:
- Complex Programmable
Logic Device (CPLD)
- Field Programmable Gate
Array (FPGA)
- Application Specific
Integrated Circuit (ASIC)
- System-on-Chip (SOC)
- Field Programmable System
Chip (FPSC)
- Variations of FPGAs and
ASICs
The CE Background section provides more
information on these devices.
Site Overview
This
web-site will help assurance engineers of all types create a
comprehensive assurance plan for complex electronics. The assurance
plan includes analyses, reviews, and techniques to use at each phase of
the project life cycle. The individual tasks are provided under the Assurance Process tab.
The set
of activities for a particular project will be a subset of the total
list. Each project phase in the Assurance
Process section will contain guidance on how to tailor the
activities to projects with various levels of safety and mission risk.
While
the assurance plan is the final result, the process of creating that
plan requires trade-offs and tailoring. Therefore, this site also
provides:
- Information on the roles
involved in creating and assuring complex electronics. This
information can be used to assign responsibility for particular
activities to individual team members.
- Ideas for how to
integrate the assurance plan with other project plans, and how to
“sell” the project on the idea of complex electronics
assurance.
- An overview of complex
electronics (CE Background).
- Information on the design process for complex electronics,
and a mapping from that process
to the project life cycle.
Site Navigation
The
horizontal navigation bar at the top has tabs for each major section in
this web site. For each major section, there is a vertical navigation
bar on the left side that links to sub-sections and pages within the
major section.
The
major sections (tabs) are:
- Home.
The home section contains general overview information,
references, and general guidance. Getting
Started suggests what parts of the web site to look at,
depending on your interest and level of knowledge. Roles-Responsibilities describe the various
roles, and associated responsibilities, for complex electronics. Training provides suggestions, with
links, for types of training an assurance engineer should consider
when working with complex electronics. Process Assurance briefly
describes process and product assurance. The
Links page has pointers to additional information that might
be of interest. The Acronyms and Glossary links should be
self-explanatory.
- CE
Background. The section main page provides an overview of the
various types of complex electronics. Other pages describe the
design process for the devices and map the complex electronics
design activities to the project life cycle.
- Assurance
Process. This section is where you will find details on the
assurance process. The section has sub-sections for each life
cycle phase. Each phase sub-section has an overview, development,
and assurance page.
- Techniques.
Most techniques included in the Assurance Process are referenced
in their life cycle phase and also under the Techniques tab. If a
technique is well documented within a NASA site, a link to the
description is provided instead of a separate write-up. This
section currently contains many techniques, but it does not
contain all the possible techniques that can be used.
- Checklists.
Checklists can be used as an aid while performing the assurance
process activities. The checklists need to be tailored to the
project and the assurance classification of the complex
electronics. Two types of checklists are included in this
assurance plan:
- Process
checklists, used to verify a sequence of steps or activities was
completed.
- Review
checklists, for various types of information (e.g. documents,
code).
- Site
Map. The Site Map lists all the pages in this web site and
provides a brief description of each page.
Each
major section has a Print this Section link
(left side navigation bar) that brings up a new window with a printer
friendly page containing all the information in the section. The
Assurance Process is an exception. Print this Section
pages in the Assurance Process sub-sections contain all the information
for a particular phase (e.g. planning or detailed design).
Motivation for a New Assurance Process
There
are currently few specific, NASA-wide requirements or processes for
assurance of complex electronics. Complex electronics are often
overlooked when a comprehensive assurance strategy and plan are created
for a project. Often, these devices are treated the same as any other
electronic component, such as an off-the-shelf microprocessor or simple
logic integrated circuit. However, such an approach does not address
the design aspects, and associated errors, of complex electronics.
Programmable
logic devices are now blurring the hardware/software boundary. FPGAs
can have from 30,000 to over a million logic gates. System-on-Chip
(SoC) devices combine a microprocessor, input and output channels, and
sometimes an FPGA for programmability. These devices can now be
programmed to perform tasks that were previously handled in software,
such as communication protocols. With increased complexity, the
possibility of “software-like” bugs (incorrect design and
logic) and unexpected interactions is greater. It is vital to be able
to assure that the systems are designed and implemented correctly,
tested fully, and reliable.
Besides
problems with testing and verifying the designs and implementations of
complex electronics, quality assurance is struggling with how to
adequately deal with the “software-like” aspects of these
devices. Some problems and concerns are:
- ASICs and FPGAs have
been used to avoid the rigors of the software assurance process.
This results in fundamental verification matters being bypassed.
- Complex Electronic
devices are designed and programmed by electronic engineers
(designers), often without quality assurance oversight or
configuration management control of the designs. In addition, the
development process may not be well defined or followed.
- ASICs, FPGAs, and
System-on-Chip (SoC) can contain embedded microprocessor cores
with user-supplied software. They combine electronics and firmware
into one chip. The presence of this firmware (i.e. software) is
not always obvious to assurance personnel.
- High-level languages
(e.g. C, C++) are now being used to define complex electronic
designs (in whole or in part).
- Hardware quality
assurance personnel may not be fully cognizant of the functions,
potential problems, and issues with these devices.
- Meaningful verification
efforts require the person performing the verification to be
knowledgeable about the complex electronic device and the tool
suite used to create and implement the design.
Based on
these perceived problems, NASA Headquarters is interested in defining
assurance requirements for complex electronics. The assurance process
developed by this research project will be validated by applying it to
existing projects. The results will be provided to NASA Headquarters as
one input into the decision process.
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