AVR-Chat

At 12:33 AM 7/9/06 -0500, Thomas J Keller wrote:
>   Best bet is to diode protect (for polarity) the input to an
>opto-isoltor on each GPIO.  This will protect you against
>static discharge, excessive positive or negative inout, etc, etc., at
>very little cost.  Cost of  a single diode, and a $0.25 (US) opto-isolator.

A question, where do you get a good linear opto for $0.25?  Especially if 
you are not dealing with a low impedance signal source.

Robert

" 'Freedom' has no meaning of itself.  There are always restrictions,   be 
they legal, genetic, or physical.  If you don't believe me, try to chew a 
radio signal. "  -- Kelvin Throop, III
http://www.aeolusdevelopment.com/