EFI ignition pickup

[Scot Sealander]

David Chambers wrote:
> 
> Hi,
> I am currently building a fuel injection computer based on a 68HC11 and
> am having trouble getting a reliable pickup for RPM. I would like to
> design the circuit so that it can be triggered from any sort of 
> ignition pulse. ....

Instead of having a universal input, why not use an input optimized for 
each type?  You could then use a mux to select the input you want to use.
Either hardware or software selectable.

Scot Sealander   Sealand at clarityconnect.com