Have y'all seen the latest "Circuit Cellar" magazine?  There's an article in
there that makes an interesting case study, WRT to the ASM vs compiler (and
related) questions.  It'a about a simulated candle (for use on-stage) using
an LED.  The simulation is based on some flame science, and includes a
random number ("White noise") generator and a floating point SW
implementation of a low pass filter, samples a self-heated thermistor to get
air current info, and drives a single PWM output.  It's done on an atmel
AT90S8535, which is a somewhat sizeable AVR (8K memory, 40pin device) to
support the single input, single output, and of course a good deal of
floating point support and compiler library support for the PWM and A-D
peripherals on the chip.

It's hard to argue with the design choices here, for a one-piece item where
the designer's time undoubtably cost a lot more than the parts.  But it's
also a design that just cries out for a "cost reduction effort"; there's no
reason I can think of that it wouldn't run in an 8-pin PIC, given some
attention to size and clever use of fixed point math.  (OTOH, Bob Pease or
other analog expert could probably convert it to a code-less design based
around a $0.30 quad op-amp, but that's another issue entirely :-)

BillW

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listserv@mitvma.mit.edu with SET PICList DIGEST in the body