Lpc2000

----- Original Message ----- 
From: "Tom Walsh" <tom@...>
To: <lpc2000@yahoogroups.com>
Sent: Friday, February 03, 2006 3:19 PM
Subject: Re: [lpc2000] Rise and fall time of capture inputs


> widescreen03608 wrote:
>
>>Hi all,
>>
>>On the CAP0.3 input I have pulses from an encoder and I want detect
>>both edges and generate interrupts. The signal is filtered so the rise
>>and fall time are slow (don't know exactly how long, but surely within
>>1ms). Is it possible that no interrupt is generated on CAP0.3, because
>>the signal is to slow?
>>
>>I didn't found any datasheets from Philips which this is described.
>>
>>
>>
> Aside from the datasheet thing, wouldn't it be possible to use a schmidt
> gate to drive the capture intput?  Or some op-amp crossing-detector with
> hysteresis?

I've done that in the past with that sort of input. I then had a problem 
with multiple signals (like contact bounce) which I eliminated with 
software.

Leon
--
Leon Heller, G1HSM
leon.heller@...
http://www.geocities.com/leon_heller