Infineon

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Topic The Importance of Documentation
Date 23 October 2006
Infineon
Presenter Serrie-justine Chapman Company
Infineon Technologies Department Automotive,
Industrial and Multimarket Job Title Senior
Verification Engineer
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The Importance of Documentation
For uwe presentation use only

• The Company
• The Documentation Flow
• The problems
• Solutions

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An Overview of the Company

• Infineon is part of the Semi-conductor industry
  making chips for various commercial purposes.
• Within Infineon we have a communications group
  which is wireless and wireline, and the
  Automotive, Industrial and Multimarket group.
• The Automotive group, alongside other safety
  critical industries such as avionics and military
  have to work to a greater quality standard than
  other groups such as wireless
• Automotive chips also work at extreme
  temperatures and have to allow for single digit
  ppm (part per million) failure rates as well as
  having to take into account the cost of
  litigation should anything fail

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Note Business units assigned to segments
according to majority of business.
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Speed of production

• In wireless there is generally a 6 month to 2
  year project run from designing the chip to
  delivering it
• In Automotive this time is increased to be closer
  to 10 years. Therefore something that we are
  working on today may not reach the Mercedes that
  it is being designed for until 2016!!
• The reason for this difference in time is because
  of issues such as the higher temperatures, higher
  quality and lead time in new car development.
• Things such as engineers leaving and thus
  valuable information being lost is a very
  expensive cost, both in terms of quality of the
  product and Time to market.
• During the lifecycle communication is VERY
  important.

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The design process

• Okay, so on the face of it, it may appear a
  simple issue
• Theres a problem
• somone solves it
• it gets discussed
• The solution is
• agreed on the customer gets the product
• The item is produced

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Reality

• 1) The customer has a problem
• 2) The Company offers a solution
• 3) It gets agreed contractually
• 4) It then gets designed
• 5) The design gets implemented
• 6) The design gets verified
• 7) The customer changes their mind and nos 2 6
  gets repeated again (this may iterate a few
  times!!)
• 8) The chip gets produced
• 9) The cutomer gets the product

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Which part is the most expensive?

• The Fabrication process production of the chip
  is most important and most expensive
• Need to ensure
• No Respin (most expensive and probably the most
  common) each spin costs between .5 2 million
  dollars takes months
• Therefore need to ensure all functionality is
  well tested and meets the user requirements
  before it goes into silicon
• Time to market is also an expensive issue make
  something too slowly then you end up with no
  customer

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Complexity

• Within each product theres the application and
  software within it, the microprocesser (which
  itself is made up of many sub blocks) then the
  system peripherals and the system itself
• At present we are working on a chip where we have
  3 ip block teams working in Bristol, the
  microprocessor team also in Bristol, then theres
  the other ip block team in Xian and the overall
  systems team in Munich.
• Most people never get to speak to their
  counterparts on a project (other than in their
  teams) and most communication is done only via
  the documentation

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System design IS complex !!
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The documentation within a typical project

• User requirements
• Concept engineering
• 1 team at the top end, then there are subteams to
  produce overall concept of design and then
  separate teams for each part of the subsytem.
  From this the Architecture Specification is
  formed
• Design spec
• Many separate blocks
• Verification spec for each implementation spec
• Maybe more dependant on what verification
  methodology is being used, but for every design
  spec at least one verification spec exists.
• RTL
• Vhdl was originally seen as an implementable spec
  but in reality too complex to use in this way
  usually many thousands of lines of code
• Tests
• currently for TriCore over 10,000 directed tests,
  hundreds of properties and coverage points and
  100 random tests

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Problems

• Semantics
• Clarity Understanding
• Constant change
• Where the documentation is
• Lack of training
• Lack of time

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Semantics The meaning or the interpretation of
a word, sentence, or other language form

• Language Translation from German or secondary
  languages or the writers understanding of the
  language is an issue. Infineon has around 35000
  employees in many wordwide locations as an
  estimate 95 of these are not natural English
  speakers.
• Syntax The grammar and how things are
  understood the book eats, shoots and leaves
  is a good example of this
• Ambiguities Words that are commonly used in the
  industry may cause issues shall, must, will etc
  may have different understandings of their
  meanings
• Also just basically what a writer means by
  something abort..

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Clarity

• Saying that something is clear to you may not be
  as clear to someone else
• If you try to explain 4 functions in one sentence
  that may be unclear
• If you try to write 1 explanation in 4 pages,
  what is the reader looking to understand within
  this??
• Understanding Will somebody read a sentence in
  the same manner as you? Do you have some other
  understanding of the system which you are failing
  to notify the user about but that you are taking
  as general knowledge and to what level should
  you explain??

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.... And the rest

• When a document is changed how thoroughly do you
  consider the effects on other documentation?
• What Documents are you using - are they the
  correct ones?
• Training ...?
• Time 20 of the time spent in a project should be
  spent ensuring that youre getting the
  documentation right!
• However what we do know is ....
• Most engineers would rather bite off a limb
  rather than comment code or do documentation.

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Solutions

• Central version controlled documentation area
• A place where the documents are stored and when
  an update occurs it can overwrite the previous
  one so the user will always pick up the latest
  release
• Agreement on language and tools for writing
  documentation
• What language will all documents be written in
  (generally english) what tool shall we use
  word/framemaker??
• Documentation Templates
• Including spec writing guidelines Avionics
  standard for ambiguous words
• Enforcing Documentation Reviews
• Need to ensure that people put aside the time to
  actually read them
• Milestones
• Include essential documents are written for a
  release to be achieved

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Link the documents

• Traceability tools
• These link the documents and force them into
  making sense to allow them to be tagged

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