Hardware capture on 16F876

[MaxiBoost]

hello again friends ,
I want make a fast rpm meter ,you understand me ofcourse ,

now I just trying on my car ,its my first dynamic test for this.
Im connect pic`s (portc.2) to car ecu rpm out .
(its same to dash board tacho in )

pic is 16F876-20
osc is 4 mhz ,I can easly rise up but I thing its not enough ..
when I use count 1000 command ,I can read on the lcd "35" every second .

then I change setting ..
35*60/2=1050 rpm ..
its near real rpm ..
I read on the tacho 1000 rpm ..
1000/60 =16.6
16.6*2 =~33.2 I think

So ,count command is very slow .

@skimask ,
Its very easy for me ,
I can try with 20 mhz osc .
Can I try ?

@Acetronics ,
Yes ,
I must write my hardware capture command ,
but question is HOW
I understand your comment ,
if I write that codes and If I use 4mhz osc ,
I can easly and faster read on my lcd 1000 to 9000 rpm ?

Tonight Im read 16F876 pdf file and work some new codes .

[Acetronics2]

[QUOTE=MaxiBoost;Yes ,
I must write my hardware capture command ,
but question is HOW
I understand your comment ,
if I write that codes and If I use 4mhz osc ,
I can easly and faster read on my lcd 1000 to 9000 rpm ?

[/QUOTE]

How ...

Take 876 Datasheet on $ 8.0, 8.1 ... CCP modules ...

an see which registers you have to deal with ...

For a first trial ... i suggest you to poll the interrupt flag rather than use an interrupt ...

for speed ... Haha ... the time is that of 1 rotation or time between two sparks ( half a rotation ...if i'm right !!! )

Alain

[skimask]

the time is that of 1 rotation or time between two sparks
Alain

What if I've got a diesel?

[Acetronics2]

Hi Skimask

You get the right to come back for 2nd week challenge !!! ...

1 rotation ... fits Diesel ALSO !!!

Ok ... can try to get the 3 phases from alternator ... but I read somewhere in this thread : ECU rpm output ...

France : 2 more points !!!

LOL !!!