AVR-Chat

Or use a schmitt trigger..

--- In AVR-Chat@yahoogroups.com, "Mark Jordan" <mark@c...> wrote:
> On 7 May 2004 at 0:32, Graham Davies wrote:
> 
> > --- In AVR-Chat@yahoogroups.com, "Phil" <phil1960us@y...> wrote:
> > 
> > > with a photo transistor, you simply
> > > pull it low and take the output 
> > > from the emitter.
> > 
> > I would think you'd need a comparator so that the input to the 
MCU 
> > was a proper logic level and not some analog signal that could 
spend 
> > a lot of time floating around between the thresholds.  Especially 
if 
> > you're expecting it to generate an interrupt.
> > 
> > Graham.
> > 
> 
> 	So use the AVR internal analog comparator. It can even 
> generate a direct interrupt or a timer capture interrupt.
> 
> 	Mark Jordan