On 14-Feb-11 15:48, Andre Abelian wrote:
> Hi all,
>
> this is for VW bug engine.
> I have square wave pulse. I use function generator to generate it. every =
4th
> pulse is
> 1 cycle. I am using pic12f683 capture input to read this pulse and I setu=
p to
> read every 4th pulse. some thing
> basic I am not picturing right. I need to find out how fast this engine (=
pulse)
> is running so engine is based on RPM
> revolution per minute. in this case I have to setup a time and count puls=
es to
> determine the speed. Since it is RPM
> counting 1 minute makes no sense so my question is how fast I should coun=
t
> pulses to determine RPM? another words
> lets say RPM shows 1000 revolution per minute if break it down will be  i=
n 1
> second 16.666 revolution so
> should I count for 1 second and expect 16 or 17 counts?
>
> I do not know for some reason I am not picturing  it right...
>
> any suggestion ?
>
>
> thanks
>
> Andre
>

         Just measuring the time between pulses and doing the math, perhaps=
?

         MJ


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