Effectiveness of RAM induction? (AFM replacement)

[Huw Scourfield]

I've built a complete ignition and FI controller based on a 16f877 pic, it
took about a week to get into pics assembly language. The difficult bit
would be testing but there is a very cheap development board available, also
the pic has so many built in features that have to be code generated in the
stamp. - Depends what is your thing really I suppose.
    Huw
----- Original Message -----
From: Diehl, Jeffrey <jdiehl at sandia.gov>
To: 'Brian Dessent ' <brian at dessent.net>; <diy_efi at diy-efi.org>
Sent: 15 October 2001 08:15
Subject: RE: Effectiveness of RAM induction? (AFM replacement)


> Ok, you give me a choice:
>
> 1. Initial complexity and improved versitility in the fomr of the
PIC-driven
> circuit.
>
> 2. Simple circuit and lots of trial and error.
>
> That's a tough call.
>
> I am a programmer by trade.  I do mostly perl, but I can do BASIC, C, 68K
> and i386 code.  I could probably learn to program a PIC.  <grin>
>
> Stamp Basic...  Sounds almost turn-key.  Is it really that easy?  I have
> built simple descrete logic circuits.  Which would be easier, PIC or
Stamp?
>
> Thanx,
> Mike Diehl.
>
> -----Original Message-----
> From: Brian Dessent
> To: diy_efi at diy-efi.org
> Sent: 10/13/2001 1:55 AM
> Subject: Re: Effectiveness of RAM induction? (AFM replacement)
>
>
> > signal, I'll convert it to voltage.  Then I'll adjust the scale with
> an
> > op-amp.  Then I'll have to plot volt v. rpm to see what kind of
> > (non)linearity I have.  I believe chips exist which will do log and
> exponent
> > functions on analog signals.  I'll bet they can be tuned to produce
> > different functions.  When the MAP looks like the AFM, the AFM is
> GONE!
> >
> > Hey, talk is cheep, but this is what I'm thinking anyway.
> >
> > Comments?
>
> You can certainly do nonlinear stuff directly in analog (there exist
> chips to do exponential, log, 4 quadrant divide, multiply) but if *I*
> were doing it I would definitely use a PIC or some other
> microcontroller.  The PIC is perfect for this job, they are designed to
> be cheap, complete, and powerful.  You could probably do the whole thing
> with a single chip.  It could probably do the freq->voltage (or a/d if
> you want to do f->v externally), loopup table conversion, and d/a (via
> PWM), as well as storing your program code in flash or eprom, clock
> generation, and automatic power-on reset, all on the one chip.  They can
> be programmed with cheap (or build-it-yourself) hardware -- if you
> choose a flash variety you don't need a UV source to erase and you can
> make a programmer with your computer's serial or parallel port for about
> $20.  Look at the 16F87X family for a start:
>
> http://www.microchip.com/14010/lit/pline/picmicro/families/16f87x/index.
> htm
>
> If assembly language isn't your thing then look at the Basic Stamp.  It
> really doesn't get much easier than these -- you write your program on
> your PC in a BASIC-like language, hit the download button, take the chip
> out to the car, and drive away.  (the stamp usues the PIC as its guts so
> that's why I mention them together.)
>
> This would surely seem easier than cobbling something together with
> various analog chips.
>
> Brian
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