On Mon, 9 Feb 2004 08:17:18 -0500, you wrote:

>First, I want to thank everyone for their valuable inputs on converting
>PIC outputs to CMOS.  Now, I have found a need to go the other way.
>
>I'd like to convert the output of a 12V 4000 Series CMOS IC to the
>digital input of my PIC16C76 which is running at 5V.
>
>Again, your help is greatly appreciated.  Thanks
>
>Dan

There are several answers...

A 47K series resistor will work, as the PIC input diodes will clamp it. =
However there can be issues
with relying on the input diodes (discussed at length in the past).
You could use a simple resistive divider - 33K and 22K would be about =
right (4.8V out at 12V in).

With both of these methods, you will be drawing some current all the time=
 the CMOS output is high.
If this is an issue, and signals are slow, you could use higher value =
resistors, up to the limit
imposed by the PIC input leakage current.=20

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