At  3:32 PM 5/25/96 -0700, James Musselman wrote:
>Doug Manzer wrote:
>> Originally my client wanted to use a PIC for this application but
>> after discussing the complexity of the math involved we decided to
>> use a processer for which a compiler was available with floating
>> point built in.

>So what processor and compiler did you go with?

We haven't decided; the NEC V25 looks interesting, especially
as it's available off the shelf on a controller board from
various vendors. A big advantage is that it's PC compatible
and we can use Borland C for programming. The firmware would
also be reasonably portable if we had to change vendors.

There's also a family of RISC controllers put out by Hitachi that
we're considering. A version of the Gnu C compiler is available
for them but I'm not sure how well it supports floating point.
Product availability may be another questionable issue.

Both of these alternatives are in a higher price range than is
(theoretically) necessary. However the client is willing to accept
the extra component cost in exchange for faster development as
time to market is critical. Although I could perhaps use the PIC
with CCS C, dropping into assembler and including some of the f/p
routines from AN575 -- assuming I could find an algorithm for
ln(x) -- this is more awkward and time consuming than using a
compiler with math.lib and the float data type built in. In fact
it turns out that future versions of the product may use
plug-in components requiring all sorts of math functions
including sin(x), etc.

I believe the PIC's have the computing power for the application,
especially the 16-bit core family which should be able handle all
this math quite easily. The problem is insufficient programming tool
support. I suppose that will improve with time. For instance there
are compilers already available for the HC11 with f/p math. I don't
know exactly how the 17Cxx stacks up against the HC11 but I presume
it's at least as powerful if not more so.

Regards, D.M.