>>>Can anyone suggest what they think the best way is to use a PIC as a
>>>tachometer-like sensor with a very low frequency input, (0-70 Hz) that
would work >>>in the background of an application?  Any suggestions and/or
code samples >>>would be GREATLY appreciated!


>>I recently finished code for an alarm/carstarter project for my car. I
found it much >>easier to measure time between pulses of my ignition coil
signal to determine >>engine speed (about 33 Hz at 1000 rpms). I just used an
interrupt to detect it, >>because of all the other things the program was
doing and the fact that the positive >>going pulse is very short and I didn't
want to scatter the code with polling snippets. >>And I used the prescaled
RTCC to do the timing. It worked very well. It just stores >>the value in a
known register, avalible at any time. If you'd like I can post the
>>interrupt handler I wrote. Good luck.


>I'd like to see this routine if you don't mind.

    Here it is. Sorry about the use of Parallax mnemonics, its all I've ever
learned. Its not optimized yet either, so uses many varibles. It is however
very flexible and easy to use. Its part of a large multitasking OS, so it may
seem kind'a over done, but it had to be this way.

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