> -----Original Message-----
> From: Michael Rigby-Jones [mailto:Michael.Rigby-Jones@BOOKHAM.COM]
> Sent: 23 September 2003 15:38
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: ] (automotive) frequency trigger
> Yes, this seems like a reasonable method to implement this,
> if you are happy to use a PIC with a CCP module.  20Hz is
> slow enough that you could easily measure this purely in
> software if you wanted to.
>

How did you do this? Just polling an input pin & using a timer? Or using the
interupt pin and a timer?


> I have recently used a small PIC to de-restrict my Japanese
> import MR2 by intercepting the signal from the speedo head to
> the ECU.  The PIC had to measure the incomming pulse and
> generate an output pulse at the same frequency up to a
> maximum limit, beyond which the output frequency remained at
> this maximum.  You are welcome to the code if you wish,
> although it does not use the CCP module.

The code could be interesting, I'd like a look please. What form was the
signal on the MR2 ? My car is a skyline, and they are very likely to be very
similar. Was is 12v square frequency/speed proportional? (like I am
assuming/guessing) ?

Thanks

jon

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