[Diy_efi] PC-laptop based efi

[Bevan Weiss]

I agree that WinNT or Win2k are stable enough for such a use, but have you
ever tried programming a driver on them??
You'll be hard pressed to be able to get an accurate timer, as well as
accurate control of the serial/parallel port to allow you to easily
communicate with the PIC processors.

It's a much better idea to stick with a system like the megasquirt, where
almost all the work has been done for you.  It can be tuned in-car using a
laptop, however importantly it doesn't _require_ the laptop to run.  ie if
you run out of laptop battery power, your car can continue running.

I think perhaps you're underestimating how much time dependant processing is
required for an ECU.  The time base that all action is based on should
ideally be synchronised to the engine itself.  As soon as you remove the
controller from direct interface with the timing device (ie reluctance
signal etc) then you start to get all kinds of synchronisation problems.

> I was thinking of probably using Win NT, or 2K, i have found it to be
quite
> stable, running for weeks or months at a time before needing a re-boot.


> >Why not ,make a unit that just has a PC interface to program and monitor
> >it, the unit runs it own microcode and is self contained and doesn't
> >need the laptop to operate, only for changes, the code and inputs could
> >be very basic.
>
> I could do this, but it would be another step. I can run a PIC(really
cheep
> and fast) to control each injector, which will maintain a fuel delivery
rate
> unless the pc tells it to change. Also, i have access to PIC's, a PIC
> programmer, and an older 486 notebook that is in need of a new life
purpose. I
> don't have motorolla microcontrollers, or 8051's etc.
> thanks for all your comments. Keep them comming!

A controller that runs the car autonomously (ie without laptop intervention)
is the best way.  It can be closely associated with the car itself without
having to worry about OS buffering and other such oddities.  If you require
hot-tuning then this can be included in the system so that the RAM values
the microcontroller uses for its calculations can be updated by the PC.  But
giving the PC total control over the engine control will be far too hard.

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