> Before it's suggested, yes, I _could_ handle it with a minor PIC, I
> may even protoype it with one anyway to verify the rest of the circuit
> and to quickly prove the logic. Due to some arcane rules, there's a
> ton of red tape to get a microprossesor based product installed at
> some of the end user sites. It's agravating, but that's the world I
> live in.

Presumably you and the red tape producers have asked the questions:

- What do we want this to do or achieve that a properly designed
processor based solution cannot achieve?

- Is the proposed solution really free of the issues which causes us
to reject a properly designed processor based solution?

- Why do we believe that?

- Do we genuinely believe that answer?

- Iterate the prior two questions until the answer to the prior
question is "Of course not! Are you mad? This is just "political"
expediency!"

- Do it, but properly.

If you are handling crucial human safety and/or big dollars (eg
nuclear station shutdown sequences, launchpad umbilical detachment,
pyro sdafing, interlocks to life threatening system, Tokamac run up /
shut down cycling  etc) do people really think that the "programming"
which goes into a logic replacement system, and/or the risk of
marginal conditions (undetected race condition, lock into forbidden
state, go mad on glitch, ...) really make it inherently safer than a
properly designed, fail safe, redundant processor based system? Do you
believe their answwer? Iterate ... :-) .



  Russell
--=20
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