On Tue, 27 Mar 2001, Graham North wrote:

> Hi,
>
> I have a +-15 Volt square wave that I want to interface to a pic. I am going
> to use the int on change to detect both the positive and negitive edges of
> the wave. The wave changes polarity approximatly every 4.5 ms.
>
> Please can someone help me, this is really holding up my project!

Do you need help with the interrupt on change part, or the voltage part?
If it's just clamping the voltage, could you not just use a couple of
diodes (like a 1N4148 and a 5V Zener), or maybe buffer it with a
transistor and then clamp with diodes?

Dale
---
The most exciting phrase to hear in science, the one that heralds new
discoveries, is not "Eureka!" (I found it!) but "That's funny ..."
                -- Isaac Asimov

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