[Diy_efi] Timing

[maier_markus at t-online.de]

Hi,

I'm doing it the following way:

- at every interrupt of a rising edge of the tooth signal, generate an
interrupt. 
- read the elapsed time from the last postivie edge to this one from a
timer and reset the timer
- the tooth time will the be stored in a shift register, that has three
entries
- move the tooth time value to a shift register:
   shift register pseudo code
   SR[2] = SR[1]
   SR[1] = SR[0]
   SR[0] = new value
- then run the gap detection: 
  - if SR[2]+SR[0] < SR[1], the overlast tooth was the gap
  - if SR[1]+SR[0] < SR[2], the over-overlast tooth was the gap and you
need 
    to react, as the gap was earlier than expected
  - if SR[1]+SR[2] < SR[0], the over-overlast tooth was the gap and you
need 
    to react, as the gap was later than expected

Please note, that the above setup requires a gap, that is at least
three teeth long.

Best regards
Markus




john smith schrieb:
> 
> Hi All,
> 
> Any one with ideas on reading and indexing a missing
> tooth wheel?
> 
> Time gap and compare with previous. If more than say
> twice as big must be a gap?
> 
> (or the engine has seized)
> 
> Any comments much appreciated.
> 
> Thanks
> 
> 
> 
> ---------------------------------
> Do You Yahoo!?
> Yahoo! Health - Feel better, live better

_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
http://www.diy-efi.org/mailman/listinfo/diy_efi