From: Bob Stout 

On Mon, 5 Apr 2004, Bruce D. Wedding wrote:

> > Hey, this is the first firmware project this company has ever done
> > that had a real honest-to-goodness functional spec of any sort!
>
> Having cut my teeth in the oil patch, I know how that goes.  "Spec?
> What's a spec?  You start coding, I'll go see what they want!"  LOL!

You got it! ;-)

> Speaking of firmware, have you seen the new Zilog Encore chips?  $39.95
> will get you a development board with 20MHz chip, flash, 10-bit ADC,
> several timers, lots of IO.  The best part is it comes with an
> uncrippled ANSI C compiler!  I ordered mine from Digikey Friday night.
> 

Sounds interesting - I'll have to check it out. For doing downhole work,
though, the choice of CPU's is quite limited. Next to satellites or some
DoD apps, downhole operation places some of the most extreme demands on the
chips. Typical operating temperatures are well in excess of even most
MIL-spec parts, as are the mechanical operating conditions. Unit testing is
done in a chamber that can go up to 500 degrees with a 100+ G shake table.
This also means only ceramic PGA packages - surface mounting a typically
large CPU will cause it to break loose within ten minutes on the shake
table. Then, of course, there's power which is at a premium running off of
batteries a mile or two below the surface.

This was probably the company's last project using the venerable 68332.
It's obsolescent, but works well in the environment. We're even using a
*lot* of FP math and it's still quite speedy for a CPU without an internal
FPU (although we are using the special 32-bit FP library - no 8-byte doubles).

> I also like the new 8051 series stuff from Silicon Labs for a bit higher
> end stuff.  

I've gotten some literature for those. Although I've used them before, I've
never really warmed up to the 8051 family or its derivatives. They're
obviously OK and often cost-competitive, but I've never been able to work
up much excitement over them. With downhole work, they're mostly a non-
issue since very very vendors make chips which will work in the downhole
environment.

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