EGO Output

[peter paul fenske]

Hi Wayne

Well a bit of filtering as the pink book is ok..

Using one of the O2 sensor chips available will help
to prevent voltage differentials from blowing the A/D.

Generally O2 is amplified by 5 to take full advantage of
A/D resolution.

yup you gotta look after overflow ie the counter is
free running and think when it reaches ffff

I posted an example a while back how to handle this
so look in the archives

gl with project:peter

At 11:54 AM 6/12/98 +1000, you wrote:
>
>Is it OK to connect the EGO sensor directly to the A/D input of a 68HC11
>processor or do I need some filtering/conditioning circuitry ?.
>I am also getting very odd readings for the injector pulse width, I am
>using a 4N25 to pull down one of the TIC inputs then changing the trigger
>for the TIC to interupt on the rising edge when the injector is turned off,
>I then calculate the pulse length from the difference in the 2 values. The
>numbers I get from this are all over the place, I do not cater for the
>timer overflow but as the timer overflow is 32.77 MS I would assume that
>the pulse length should be much less than that. Do I need some sort of
>filtering on the signal from the ECU ?.
>
>     TIA
>          Wayne
>
>
>
>