Microcontroller shielding questions

[Intec Inoventures Inc.]

Hi All,

I am designing a small (2"x2") controller board for use in the automotive
and robotics industries.  The board is based on the MC68HC16Z1
microcontroller.  Since the engine compartment of a car is filled with EMI
we are attempting to make the board as resistant as possible to the effects
of the EMI.

Since I don't know the specifics of the sources of EMI a an automobile I
would appreciate anyone who could help me with the following questions and
maybe give some extra advice on things I have not asked about but are of
concern in this type of design.

What are the frequency and voltage levels of noise present in the typical
automobile (EFI, and carburettor type)?

What is the strength of the magnetic waves created by spark plugs and/or
distributors?  What is currently done to protect against it?

What type of wire is used to connect a controller to the rest of the system
(shielded, unshielded, twisted pair)?

Can anyone give me some information on how to determined the type of
shielding to use (box type and thickness, feed through type and value)?
What is necessary?  What is commonly used and what is affordable?

Thanks in advance,

Wade Barnes, Electronics Tech.
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