Cheap protection...

[Bernd Felsche]

Scotty Grover writes:

>> I don't think the 74C14 Schmitt trigger would like 12V input if it's
>> running from a 5V supply rail. The Schmitt trigger connects to the
>> inputs of the uC, which shares the regulated 5V supply.

>'Scuse me for butting in, but a CD4049 (Inverting) or CD4050
>(Non-inverting) may work better than a 74C14.  The CD's (Powered by
>5V) accept 15V at their inputs.

Thanks.

You're excused for butting in. :-)

That brings the parts count down nicely; just a series resistor
required ahead of the buffer for minimal protection.

-- 
Real Name: Bernd Felsche
    Email: nospam.bernie at perth.DIALix.com.au
     http://www.perth.dialix.com.au/~bernie - Private HP
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